CA2185399A1 - Mobile communication method and system - Google Patents
Mobile communication method and systemInfo
- Publication number
- CA2185399A1 CA2185399A1 CA002185399A CA2185399A CA2185399A1 CA 2185399 A1 CA2185399 A1 CA 2185399A1 CA 002185399 A CA002185399 A CA 002185399A CA 2185399 A CA2185399 A CA 2185399A CA 2185399 A1 CA2185399 A1 CA 2185399A1
- Authority
- CA
- Canada
- Prior art keywords
- code
- control channel
- base station
- mobile unit
- mobile
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
- H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
- H04B7/2628—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA]
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W48/00—Access restriction; Network selection; Access point selection
- H04W48/18—Selecting a network or a communication service
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/02—Terminal devices
- H04W88/06—Terminal devices adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/08—Access point devices
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
- H04W16/14—Spectrum sharing arrangements between different networks
- H04W16/16—Spectrum sharing arrangements between different networks for PBS [Private Base Station] arrangements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/02—Power saving arrangements
- H04W52/0209—Power saving arrangements in terminal devices
- H04W52/0212—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave
- H04W52/0216—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave using a pre-established activity schedule, e.g. traffic indication frame
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/02—Power saving arrangements
- H04W52/0209—Power saving arrangements in terminal devices
- H04W52/0212—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave
- H04W52/0219—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave where the power saving management affects multiple terminals
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
A mobile communication system in which a mobile unit of a mobile communication system operating under the CDMA system may be utilized indoors as a slave unit of the cordless telephone. The communication system operating under the CDMA system includes a plurality of fixed stations 3 connected to a subscriber network and designed to send a PN code shorter in period than a pilot PN code sent from a base station 1, and the identification information for the fixed stations 3, as a control channel, and a mobile unit 2 for receiving the identification information in the control channel received from the fixed station and for making or accepting a call via the fixed station 3 and via the base station 1 if the mobile unit 2 has identified the fixed station to be its own fixed station based on the identification information and otherwise, respectively.
Description
~ 2 ~ 8r~399 s,~?"~
TITLE OF THE INVENTION
Mobile Communication Method and System BACKGROUND OF TEIE INVENT:E~ON
Field of the Invention This invention relates to a method and a system for mobile communication, a fixed station and a mobile station. More particularly, it relates to a cellular system employing the code division multiple access (CDMA) system or a system for indoor utilization of a mobile station of a licensed PCS.
Description of the Relate~d Art The mobile communication employing the CDMA system, or a so-called cellular system, has a system capacity about ten times as large as that of the conventional analog mobile communication system, and is now coming into widespread use in the licensed personal communication service (PCS).
In a digital cellular employing the CDMf.~ system, a base station 1 and a plurality of mobile units are interconnected by a radio network of a pre-set band, as shown in Fig.1. As a so-called forward link from the base station 1 to the mobile units 2, a pilot channel, a sink channel, a paging channel and a traffics channel are used.
The pilot channel is a channel for repetitive transmission of a pilot PN code and is used for acquisition and maintenance of synchronization at the mobile unit 2 and for clock regeneration.
The sync channel is a ch~nnel used for matching the time and `-- 2 ~ rd 5399 the PN code, that is a 60-called long code, between the base station 1 and the mobile unit 2.
The paging channel is a channel used for transmLtting the in~ormation required for hand-off, calling information for the mobile unit 2 on termination or the information on trafficæ channel al location.
The traffics channel is a channel used for transmitting the actual speech information (speech data) or data.
Referring to Fig.2, the base station 1 includes a PN code generator 101 for generating the PN code, Walsh code generators 1020 to 102*, and multipliers 1030 to 103n for multiplying the PN
code from the PN code generator 101 with the Walsh codes from the Walsh code generators 1020 to 102n, where n may, for example, be equal to 63. The base station 1 also includes multipliers 1041 to 104n for multiplying outputs of the multipliers 1031 to 103n with the outputs of the multipliers 1031 to 103n and data, and a channel adder 105 for summing the outputs of the multipliers 1041 to 104n.
The multiplier 1030 multiplies the PN code from the PN code generator 101 with the Walsh code 0, i.e., all-zero, which is the orthogonal code from the Walsh code generator 1020, and routes the resulting PN code to the adder 105 as pilot channel data.
The multiplier 103~2 multiplies the PN code from the PN code generator 101 with the Walsh code 32 from the Walsh code generator 102~2, while the multiplier 104~2 multiplies an output of the mulelpller 103~, wlth d~t~ oh s tlme ~n~orm~tion, ~ul~plled vla ` ~ 2185399 terminal 106, and routes the resulting data to the adder lOS as sync channel data.
The multiplier 103l multiplies the PN code from the PN code generator 101 with the Walsh code 1 from the Walsh code generator 1021, while the multiplier 104l multiplies the output of the multiplier 103l with, for example, the allocation information for the paging channel supplied via a terminal 107, and routes the resulting data to the adder 105 as the paging channel data. It is possible to provide up to seven channels at the maximum for constituting the paging channel data.
The multiplier 103l multiplies the PN code from the PN code generator 101 with the Walsh code i from the Walsh code generator 102i, while the multiplier 104l multiplies an output of the multiplier 103l with, for example, speech data supplied via a terminal 108l, and routes the resulting data to the adder 105 as traffics channel data.
The adder 105 sums the pilot channel data from the multiplier 1030, sync channel data from the multiplier 104,~, paging channel data from the multiplier 104l and the traffics channel data from the multipliers 103l, and r.outes the resulting data via a terminal 109 to, for example, a two-phase phase shift keying modulator, not shown .
When the synchronization (timing) of the PN code of the mobile ætation 2 is maintained, using, for example, the pilot channel, and the shift quantity of the PN code is notified to the mobile station ~ 2 t 85399 2, using the sync channel, calling responsive to call acceptance and traffics channel allo.cation are performed, using the paging channel. That is, actual talk oYer the telephone is had by the CDMA
system, using the traffics channel. Meanwhile, an access channel for controlling making of a call or accepting a call, and a traffics channel for having a talk over the telephone, are used as a so-called reverse link from the mobile unit 2 to the base station 1. . .
In the cellular system or the licensed PCS, it would be highly convenient that, when the mobile unit (mobile terminal) is situated indoors, as shown in Fig.l, the mobile unit 2 can be used as a slave unit in the so-called cordless telephone, that is as a slave unit for a master unit connected to the subscriber network (home base station), in order to exploit the subscriber network for which the charging for the call is low. State differently, a demand has been raised for the mobile unit 2 and the home base station 3 having the above function.
The home base station is now coming into use insofar as time division multiple access (TDMA) system is concerned. The TDMA
system is in operation under the same system as the cellular system by searching for void channels not used as the cellular.
If, in the system employing the home base station of the CDMA
system, the cellular mode is automatically changed over to the cordless telephone mode, it is necessary for the mobile unit to search the home base station per;odically. In such case, however, the following problems arise.
In the cellular of the CDMA system, the mobile unit periodically receives the paging channel to check for the possible presence of termination without regard to system types. Thus it is necessary for the mobile unit to search the home base station in interstitial time periods.
E~owever, it is extremely difficult to reaLize synchronization between the base station and the home base station. Moreover, the pilot PN code period used in the CDMA system is extremely long, being 215, such that it takes prolonged time to find the correlation for all timings for detecting the pilot PN code. For example, if the length of correlation ls 64 chips, it takes time on the order of 2 seconds before arriving at the results of correlation for all timings. Since te length o:f correlation is several times as long as the above value, it takes an extremely long time before detecting the pilot PN code. Thus, i~ the home base station transmits the pilot PN signal (code) and the mobile unit attempts to detect the transmitted code, it is difficult to search the home base station during the above period.
If ~he home base station keeps on transmitting the pilot PN
signal, it may prove to be a hindrance to other systems in operation. It is desirable to reduce the transmission time ratio by burst-like transmission, i~ this is possible.
Sl~MMA~Y OF TE~E INVENTION
It is therefore an object of the present invention to provide -~ ` 2 ~ ~ ~399 a method and a system for mobile communication, a fixed station and a mobile station in which it is possible to utilize a mobile unit of the cellular system or licensed PCS employing the CDMA system as a slave unit of the cordless telephone if the mobile unit happens to be situated indoors.
In one aspect, the present invention provides a method for mobile transmission for having communication between a base station and a plurality of mobile units by a code division multiple connection system, there being a plurality of fixed stations connected to the subscriber network in association with the mobile units, wherein N periods of the PN codes shorter in period than a pilot PN code transmitted from the base station, N being not less than 1, and the i dent i f i~c at i on inf o rmat i on f o r i dent i f y i ng the fixed stations, are transmitted as a control channel, and wherein, if a fixed station has been confirmed by the mobile unit to be the fixed station associated with the mobile unit based on the identification information of the control channel received by the fixed station, a call is ~made or accepted via the fixed station and, if otherwise, a call is made or accepted via the base station. Thus the mobile unit can receive the control channel from the fixed station in a shorter time.
In another aspect, the present invention provides a system for mobile transmission for having communication between a base station and a plurality of mobile units by a code division multiple onneo~ion ~Y~tem noludin ~ plur~lity oi ed ~ti~n6 i~r .~` 21~5399 transmitting N periods of the a PN code, shorter in period than a pilot PN code transmltted from the base station, N being not less than 1, and for transmitting the identification information for identifying the fixed stations, as a control channel, and a plurality of mobile units which, if a fixed station has been confirmed by the mobile unit to be the fixed station associated with the mobile unit based on the identification information of the control channel received by the fixed station, malse or accept a call via the fixed station and, if otherwise, make or accept a call via the base station. The fixed stations are assoclated with the mobile units and are connected to a subscriber network.
In still another aspect, the present invention provides a fixed station in a mobile communication system designed for having communication between a base ~tation and a plurality of mobile units by a code division multiple connection system. The fixed station has a radio communication with the mobile unit. The fixed station has PN code generating means for generating a PN code shorter in period than a pilot PN code transmitted from the base station, identification information generating means for generating the identification information for identifying the fixed stations, and control channel transmitting means for transmitting N periods of the PN code from the PN code generating means, N being not less than 1, and the ldentification information from the identification information generating means, as a control channel.
In yet another aspect, th~ present invention provides a mobile 21 8~399 unit in a mobile communication system in which communication is had between a base station and a plurality of the mobile units by a code division multiple connection system. The mobile unit includes reception means for receiving a paging channel from the base station and for receivlng N periods, N being not less than 1, of PN codes shorter ln_per~iod than a pilot PN code, and the identification information for identifying a plurality of fixed stations associated with the mobile units as a control c!~annel, PN
code detection means for detecting the PN codes of the control channel received by the reception means, demodulation means for demodulating the identification information of the control channel based on the result of detection of the PN code detection means and control means managing control for making a call or acceptin~ a call via a fixed station if the fixed station has been confirmed by the mobile unit to be :the fixed station associated with the mobile unit based on the identification information from the demodulation means. Otherwise, the control means manages control for making or acceptin~ a call via the base station.
Preferably, the fixed station transmits the controL channel in a time interval shorter~ than the time which elapses since the end of a paging channel intermittently transmitted from the base station until the leading end of the next paging channel. Thus the mobile unit can receive the control channel in the interstitial period of reception of the paging channels.
Pr~fer~bl1 ~he fixe ~t~tlo~ v~ri~ the timing of ,~, .
transmitting the control channel based on random numbers. This makes it possible to avoid continuous collision of a control packet sent from a fixed station against a control packet transmitted by ano ther f ixed s tat i on .
Preferably, a plurality of the fixed stations transmit control channels of respectively different PN codes. This enables the mobile unit to use the Pn code of the control channel for identifying the associated fixed station.
Preferably, the mobile unit intermittently receives the paging channel transmitted from the base station, and the control channel from the fixed station is received during the period of not receiving the paging channel.
Preferably, the mobile unit may be adapted for receiving the control channel once for reception of one or more paging channel(s). This makes it possible to reduce power consumption otherwise increased by control channel reception.
According to the present invention, the fixed station connected to the subscriber line transmits N periods of the PN code shorter in period than the pilot PN code sent from the base station, and the identification information for identifying the fixed stations, as a control char,nel. If the mobile unit has identified a fixed station to be its own fixed station, based on the identification information of the control channel received from the fixed station, it makes or accepts a call via the fixed station. If otherwise, the mobile unit makes or accepts a call via ` ~` 21 85399 the base station.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig.1 s a conceptual view showing a home base station.
Fig.2 is a block diagram showing an illustrative arrangement of a transmission system of a base station.
Fig.3 is a block diagram showing an illustrative arrangement of a transmission system of a home base station embodying the present invention.
Figs.4A to 4D are timing charts showing the operating timing of a receiver oi~ a mobile~ unit embodying the present invention.
Fig.5 is a block diagram showing an illustrative arrangement of the receiver o~ the mobile unit.
Figs . 6A and 8B are timing charts for illustrating the transmission of the paging channel of the base station and the operation of the receiving unit.
Figs.7A to 7C are timing charts for illustrating timing charts for illustrating the relation between the paging channel, control channel and the recelver operation.
Fig.8 is a block diagram showing an illustrative arrangement of a PN detector of the mobile unit.
Fig.9 is a block diagram showing an illustrative arrangement of a PN code generator of a PN detector.
Fig. 10 is a flowchart for illustrating the operating mode switching operation oi~ a mobile unit.
Fig. 11 is another flowchart for 11 lustrating the operating . . 21 85399 mode switching operation of a mobile unit.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, preferred embodiments of the method and the system for mobile communication, a fixed station and a mobile gtation.
The mobile communication system according to the present invention performs communication between a base station 1, plural mobile units 2 and a home base station (BS) 3, as a fixed station, using the CDMA system, as shown in Fig.l. In this system, the HBS
TITLE OF THE INVENTION
Mobile Communication Method and System BACKGROUND OF TEIE INVENT:E~ON
Field of the Invention This invention relates to a method and a system for mobile communication, a fixed station and a mobile station. More particularly, it relates to a cellular system employing the code division multiple access (CDMA) system or a system for indoor utilization of a mobile station of a licensed PCS.
Description of the Relate~d Art The mobile communication employing the CDMA system, or a so-called cellular system, has a system capacity about ten times as large as that of the conventional analog mobile communication system, and is now coming into widespread use in the licensed personal communication service (PCS).
In a digital cellular employing the CDMf.~ system, a base station 1 and a plurality of mobile units are interconnected by a radio network of a pre-set band, as shown in Fig.1. As a so-called forward link from the base station 1 to the mobile units 2, a pilot channel, a sink channel, a paging channel and a traffics channel are used.
The pilot channel is a channel for repetitive transmission of a pilot PN code and is used for acquisition and maintenance of synchronization at the mobile unit 2 and for clock regeneration.
The sync channel is a ch~nnel used for matching the time and `-- 2 ~ rd 5399 the PN code, that is a 60-called long code, between the base station 1 and the mobile unit 2.
The paging channel is a channel used for transmLtting the in~ormation required for hand-off, calling information for the mobile unit 2 on termination or the information on trafficæ channel al location.
The traffics channel is a channel used for transmitting the actual speech information (speech data) or data.
Referring to Fig.2, the base station 1 includes a PN code generator 101 for generating the PN code, Walsh code generators 1020 to 102*, and multipliers 1030 to 103n for multiplying the PN
code from the PN code generator 101 with the Walsh codes from the Walsh code generators 1020 to 102n, where n may, for example, be equal to 63. The base station 1 also includes multipliers 1041 to 104n for multiplying outputs of the multipliers 1031 to 103n with the outputs of the multipliers 1031 to 103n and data, and a channel adder 105 for summing the outputs of the multipliers 1041 to 104n.
The multiplier 1030 multiplies the PN code from the PN code generator 101 with the Walsh code 0, i.e., all-zero, which is the orthogonal code from the Walsh code generator 1020, and routes the resulting PN code to the adder 105 as pilot channel data.
The multiplier 103~2 multiplies the PN code from the PN code generator 101 with the Walsh code 32 from the Walsh code generator 102~2, while the multiplier 104~2 multiplies an output of the mulelpller 103~, wlth d~t~ oh s tlme ~n~orm~tion, ~ul~plled vla ` ~ 2185399 terminal 106, and routes the resulting data to the adder lOS as sync channel data.
The multiplier 103l multiplies the PN code from the PN code generator 101 with the Walsh code 1 from the Walsh code generator 1021, while the multiplier 104l multiplies the output of the multiplier 103l with, for example, the allocation information for the paging channel supplied via a terminal 107, and routes the resulting data to the adder 105 as the paging channel data. It is possible to provide up to seven channels at the maximum for constituting the paging channel data.
The multiplier 103l multiplies the PN code from the PN code generator 101 with the Walsh code i from the Walsh code generator 102i, while the multiplier 104l multiplies an output of the multiplier 103l with, for example, speech data supplied via a terminal 108l, and routes the resulting data to the adder 105 as traffics channel data.
The adder 105 sums the pilot channel data from the multiplier 1030, sync channel data from the multiplier 104,~, paging channel data from the multiplier 104l and the traffics channel data from the multipliers 103l, and r.outes the resulting data via a terminal 109 to, for example, a two-phase phase shift keying modulator, not shown .
When the synchronization (timing) of the PN code of the mobile ætation 2 is maintained, using, for example, the pilot channel, and the shift quantity of the PN code is notified to the mobile station ~ 2 t 85399 2, using the sync channel, calling responsive to call acceptance and traffics channel allo.cation are performed, using the paging channel. That is, actual talk oYer the telephone is had by the CDMA
system, using the traffics channel. Meanwhile, an access channel for controlling making of a call or accepting a call, and a traffics channel for having a talk over the telephone, are used as a so-called reverse link from the mobile unit 2 to the base station 1. . .
In the cellular system or the licensed PCS, it would be highly convenient that, when the mobile unit (mobile terminal) is situated indoors, as shown in Fig.l, the mobile unit 2 can be used as a slave unit in the so-called cordless telephone, that is as a slave unit for a master unit connected to the subscriber network (home base station), in order to exploit the subscriber network for which the charging for the call is low. State differently, a demand has been raised for the mobile unit 2 and the home base station 3 having the above function.
The home base station is now coming into use insofar as time division multiple access (TDMA) system is concerned. The TDMA
system is in operation under the same system as the cellular system by searching for void channels not used as the cellular.
If, in the system employing the home base station of the CDMA
system, the cellular mode is automatically changed over to the cordless telephone mode, it is necessary for the mobile unit to search the home base station per;odically. In such case, however, the following problems arise.
In the cellular of the CDMA system, the mobile unit periodically receives the paging channel to check for the possible presence of termination without regard to system types. Thus it is necessary for the mobile unit to search the home base station in interstitial time periods.
E~owever, it is extremely difficult to reaLize synchronization between the base station and the home base station. Moreover, the pilot PN code period used in the CDMA system is extremely long, being 215, such that it takes prolonged time to find the correlation for all timings for detecting the pilot PN code. For example, if the length of correlation ls 64 chips, it takes time on the order of 2 seconds before arriving at the results of correlation for all timings. Since te length o:f correlation is several times as long as the above value, it takes an extremely long time before detecting the pilot PN code. Thus, i~ the home base station transmits the pilot PN signal (code) and the mobile unit attempts to detect the transmitted code, it is difficult to search the home base station during the above period.
If ~he home base station keeps on transmitting the pilot PN
signal, it may prove to be a hindrance to other systems in operation. It is desirable to reduce the transmission time ratio by burst-like transmission, i~ this is possible.
Sl~MMA~Y OF TE~E INVENTION
It is therefore an object of the present invention to provide -~ ` 2 ~ ~ ~399 a method and a system for mobile communication, a fixed station and a mobile station in which it is possible to utilize a mobile unit of the cellular system or licensed PCS employing the CDMA system as a slave unit of the cordless telephone if the mobile unit happens to be situated indoors.
In one aspect, the present invention provides a method for mobile transmission for having communication between a base station and a plurality of mobile units by a code division multiple connection system, there being a plurality of fixed stations connected to the subscriber network in association with the mobile units, wherein N periods of the PN codes shorter in period than a pilot PN code transmitted from the base station, N being not less than 1, and the i dent i f i~c at i on inf o rmat i on f o r i dent i f y i ng the fixed stations, are transmitted as a control channel, and wherein, if a fixed station has been confirmed by the mobile unit to be the fixed station associated with the mobile unit based on the identification information of the control channel received by the fixed station, a call is ~made or accepted via the fixed station and, if otherwise, a call is made or accepted via the base station. Thus the mobile unit can receive the control channel from the fixed station in a shorter time.
In another aspect, the present invention provides a system for mobile transmission for having communication between a base station and a plurality of mobile units by a code division multiple onneo~ion ~Y~tem noludin ~ plur~lity oi ed ~ti~n6 i~r .~` 21~5399 transmitting N periods of the a PN code, shorter in period than a pilot PN code transmltted from the base station, N being not less than 1, and for transmitting the identification information for identifying the fixed stations, as a control channel, and a plurality of mobile units which, if a fixed station has been confirmed by the mobile unit to be the fixed station associated with the mobile unit based on the identification information of the control channel received by the fixed station, malse or accept a call via the fixed station and, if otherwise, make or accept a call via the base station. The fixed stations are assoclated with the mobile units and are connected to a subscriber network.
In still another aspect, the present invention provides a fixed station in a mobile communication system designed for having communication between a base ~tation and a plurality of mobile units by a code division multiple connection system. The fixed station has a radio communication with the mobile unit. The fixed station has PN code generating means for generating a PN code shorter in period than a pilot PN code transmitted from the base station, identification information generating means for generating the identification information for identifying the fixed stations, and control channel transmitting means for transmitting N periods of the PN code from the PN code generating means, N being not less than 1, and the ldentification information from the identification information generating means, as a control channel.
In yet another aspect, th~ present invention provides a mobile 21 8~399 unit in a mobile communication system in which communication is had between a base station and a plurality of the mobile units by a code division multiple connection system. The mobile unit includes reception means for receiving a paging channel from the base station and for receivlng N periods, N being not less than 1, of PN codes shorter ln_per~iod than a pilot PN code, and the identification information for identifying a plurality of fixed stations associated with the mobile units as a control c!~annel, PN
code detection means for detecting the PN codes of the control channel received by the reception means, demodulation means for demodulating the identification information of the control channel based on the result of detection of the PN code detection means and control means managing control for making a call or acceptin~ a call via a fixed station if the fixed station has been confirmed by the mobile unit to be :the fixed station associated with the mobile unit based on the identification information from the demodulation means. Otherwise, the control means manages control for making or acceptin~ a call via the base station.
Preferably, the fixed station transmits the controL channel in a time interval shorter~ than the time which elapses since the end of a paging channel intermittently transmitted from the base station until the leading end of the next paging channel. Thus the mobile unit can receive the control channel in the interstitial period of reception of the paging channels.
Pr~fer~bl1 ~he fixe ~t~tlo~ v~ri~ the timing of ,~, .
transmitting the control channel based on random numbers. This makes it possible to avoid continuous collision of a control packet sent from a fixed station against a control packet transmitted by ano ther f ixed s tat i on .
Preferably, a plurality of the fixed stations transmit control channels of respectively different PN codes. This enables the mobile unit to use the Pn code of the control channel for identifying the associated fixed station.
Preferably, the mobile unit intermittently receives the paging channel transmitted from the base station, and the control channel from the fixed station is received during the period of not receiving the paging channel.
Preferably, the mobile unit may be adapted for receiving the control channel once for reception of one or more paging channel(s). This makes it possible to reduce power consumption otherwise increased by control channel reception.
According to the present invention, the fixed station connected to the subscriber line transmits N periods of the PN code shorter in period than the pilot PN code sent from the base station, and the identification information for identifying the fixed stations, as a control char,nel. If the mobile unit has identified a fixed station to be its own fixed station, based on the identification information of the control channel received from the fixed station, it makes or accepts a call via the fixed station. If otherwise, the mobile unit makes or accepts a call via ` ~` 21 85399 the base station.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig.1 s a conceptual view showing a home base station.
Fig.2 is a block diagram showing an illustrative arrangement of a transmission system of a base station.
Fig.3 is a block diagram showing an illustrative arrangement of a transmission system of a home base station embodying the present invention.
Figs.4A to 4D are timing charts showing the operating timing of a receiver oi~ a mobile~ unit embodying the present invention.
Fig.5 is a block diagram showing an illustrative arrangement of the receiver o~ the mobile unit.
Figs . 6A and 8B are timing charts for illustrating the transmission of the paging channel of the base station and the operation of the receiving unit.
Figs.7A to 7C are timing charts for illustrating timing charts for illustrating the relation between the paging channel, control channel and the recelver operation.
Fig.8 is a block diagram showing an illustrative arrangement of a PN detector of the mobile unit.
Fig.9 is a block diagram showing an illustrative arrangement of a PN code generator of a PN detector.
Fig. 10 is a flowchart for illustrating the operating mode switching operation oi~ a mobile unit.
Fig. 11 is another flowchart for 11 lustrating the operating . . 21 85399 mode switching operation of a mobile unit.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, preferred embodiments of the method and the system for mobile communication, a fixed station and a mobile gtation.
The mobile communication system according to the present invention performs communication between a base station 1, plural mobile units 2 and a home base station (BS) 3, as a fixed station, using the CDMA system, as shown in Fig.l. In this system, the HBS
3, connected to the subscriber network, transmits N periods, N
being not less than 1, of the PN code having a period shorter than that of the pilot PN code transmitted from the base station 1, and the identification information for identifying the HBS, as a control channel. The mobile unit 2 is resPOnsive to the identification information for the control channel received from the HBS 3 to make a call or ~accept a call via the HBS 3 if the HBS
3 has been identified to be its o~n HBS. If other~ise, the mobile unit makes a cal or accepts a call via the base station 1.
With the mobile communication system, the mobile unit 2 situated in an area capable of having communication with the BS
3 situated indoors can be used as a slave unit of the so-called cordless telephone. At this time, the mobile unit 2 operates under an HBS mode of making or accepting a call via HBS 3 equivalent to the master unit connected to the subscriber network. If the mobile unit 2 is situated in an are ncapable of having communication .` 21 85399 with the HBS3, it operates under a cellular mode of making or accepting a call via the base station 1.
Ei'ig.3 shows an example: of the constitution of a transmission system of the BS 3. T~e HBS 3 includes a transmission data generating circuit 11 for outputting the encoded speech data in a pre-set format and a control circuit 12 for generating the identification information for identifying the home base stations 3. The HBS 3 also includes a control pacl~et generating circuit 15 for outputting the identification from the control circuit 12 in a pre-set format and a PN code generator for generating a PN code having a period shorter than that of the pilot PN code of the paging channel transmitted from the base station. The HBS 3 also includes a plurality of, herein three, Walsh code generators 22 to 24 for generating respectively different Walsh codes and multiplier~s 25 to 27 for multiplying the PN codes from the PN code generator 21 with the Walsh codes from the Walsh code generators 22 to 24. The HBS 3 also includes a multiplier 28 for multiplYing the identification information generated by the control circuit 12 with an output of the multiplier 26 and a multiplier 29 for multiplying the speech data outputted by the transmissLon data generating circuit 11 with an output of the multiplier 27. The HBS
3 additionally includes an adder 30 for summing outputs of the multipliers 25, 28, 29 and a modulator 31 for modulating an output of the channel adder 30 in :accordance with a pre-set modulation system. The BS 3 further includ s a high freouency ampli/ier 32 . . 2185399 for amplifying the modulated signal from the modulator 31 and an antenna 33.
When a call has been accepted via subscriber network, the control circuit 12 generat~es the control information for network control, such as calling responsive to accepted call, while generating the identificatiDn information for identification of the respective home base stations allocated to the home base stations 3 at a time interval shorter than the time duration as from the end of a paging channel intermittently transmitted from the base station 1 until the leading end of the next paging channel. This control information is supplied to the transmission data generating circuit 11, while the identification information is supplicd to the control packet generating circuit 15.
During telephone talk, the transmission data generating circuit 11 is fed via a terminal 18 with speech data encoded by a pre-set coding rule (encoded speech data). The transmission data generating circuit 11 converts the encoded speech data and the control information for network control supplied from the control circuit 12, and routes the resulting format-converted data to a encoding circuit 13. The encoding circuit 13 encodes the format-converted encoded speech data using, for example, convolutional codes for making error correction in the mobile unit Z. An interleaving circuit 14 interleaves the ended speech data so that no burst error will be produced in the encoded speech data, and routes the encoded speech dat. to the multiplier 29.
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On the other hand, the control packet generating circuit 15 converts the identLfication information proper to the HBS 3 and routes the resulting packet to an encoding circuit 16. Similarly to the encoding circuit 13, the encoding circuit 16 encodes the identification information. Likewise, the interleaving circuit 17 interleaves the encoded identification ini~ormation, as in the case of the interleaving circuit 14, and routes the resulting interleaved encoded identification information to the multiplier 28 .
The PN code generator 21 generates the PN code with a period e~ual to, for e2~ample, 2~, which is shorter than the time which elapses since the end of the paging channel intermittently transmitted from the base station 1 until the lading end of the next paging channel, and sends the PN code to the multipliers 25 to 27.
The Walsh code generator 22 generates the Walsh codes O, i.e., all-zero, which is the orthogonal code. The multiplier 25 multiplies the Walsh code O with the PN code supplied from the PN
generator 21 and routes the resulting code to the channel adder 30.
The Walsh code generator 23 generates Walsh codes m, where m is a pre-selected integer from 1 to 63. The multiplier 26 multiplies the Walsh codes m with the PN code supplied from the PN
generator 21 and sends the resulting product data to the multiplier 28. The multiplier 28 is fed with the interleaved identiiication information from the interleaving circuit 17. The multiplier ~ . ~1 85399 multiplies the identification code with and output of the multiplier 26 and routes the resulting data to the channel adder 30 .
The Walsh code generator 24 generates Walsh codes k, where k is a pre-selected integer from 1 to 63. The multiplier 27 multiplies the Walsh codes k with the PN code supplied from the PN
generator 21 and sends the resulting product data to the multiplier 29. The multiplier 28 is fed with the interleaved identification information from the interleaving circuit 1~. The multiplier multiplies the identification code with an output of the multiplier 26 and routes the resulting data to the channel adder 30.
The channel adder 30 sums the outputs of the multipliers 25, 28, 29 and routes the resulting sum data as the transmission data to the modulator 31. Specifically, the channel adder 30 is continuously fed from the base station 1 with a paging message (paging channel) containing the pilot PN code having a period of 1.28 sec 2N, where N is not less than 1, as shown for example in Fig.4A. The channel adder 30 forms a control channel made up of a preamble containing the PN code and data containing the identification information, while outputting this control channel as a control packet at a period shorter than the period of the paging message. The transmission timing of the control packet (control channel) may be varied on the basis of random numbers for avoiding continuous collision of the control packets sent from the other home base station agaln~t ~e control packet transmitted by ~ 21 8~399 the HBS 3.
The modulator 31 is comprised of pre-set modulators, for example, a two-phase phase shift keying (PSK) modulator or a Quadrature phase shift keying (QPSK) modulator, and modulates two carrier waves having phase shift of ,~/2 from each other with the control channel supplied form the channel adder 30 and with encoded speech data if the mobile unit is belng used for talk. The resulting modulated signal is supplied to a high freQuency amplifier 32 which then amplifies the modulated signal and sends the amplified signal via antenna 33 to the high frequencY amplifier 32. Thus the BS 3 transmits the control channel at least once during the time since the end of the paging channel intermittently transmitted from the base station 1 until the leading end of the next paging channel.
l~eferring now to Fig.5, an illustrative structure of the mobile unit 2 is explained.
In Fig.5, the mobile unit 2 has, as its receiving portions, an antenna 41 for receivlng modulated signals from the base station 1 and the EIBS 3, and a high frequency amplifier 42 received by the antenna 41. The mobile unit 2 also includes an orthogonal detection circuit 43 for converting the high-freQuency modulated signal for converting the detected signal into the base-band signal and a PN detection unit 44 for detecting the pilot PN code from the base station 1 and the PN code from the HBS 3. The mobile unit 2 also includes a plurality of, herein three, demodulators 451, 45 ` ` 21 85399 and 45~ for demodulating the baseband signal from the orthogonal detection circuit 43 and a synthesis unit 46 for synthesizing the outputs of the demodulators 451 to 45~. The mobile unit 2 also includes a deinterleaver 47 for deinterleaving the decoded data and a decoder 48 for error-correcting the decoding data. The mobile unit 2 finally includes a receiver control circuit 49 controlling the PN detector 44 and so forth, and= a vocoder 50 for reproducing speech data.
In a so-called idling~state, the mobile unit 2 receives the paging channel from the base: station 1, while receiving the control channel from the HBS 3 in :the interstitial periods between the times of reception of the paging channel. If the mobile unit 2 has succeeded in identifying its own BS 3, it operates in the BS mode of making a call or accepting a call via this EBS 3, and otherwise operates in the cellular mode of making a call or accepting a call via the base station 1. Stated differently, the mobile unit 2 operates :~s a slave unit of the cordless telephone in an area capable of having telephone communic~tion with, for example, an indoor BS 3, that is, it makes a call or accepts a call via an HBS
3 connected to the subscriber network. In an area incapable of having telephone communication, the mobile unit 2 operates as a mobile terminal making a cal~ and accepting a call via the base station l.
Specifically, the high frequency amplifier 42 amplifies the modulated signal, received over an antenna 41, while the orthogonal 2f ~5399 detection circuit 43 orthogonally detects the modulated signal and routes the resulting base-band signal to the PN detector 44 and to the amplifiers 45~ to 45~.
In the idling state of the receiver of the mobile unit 2, the PN detector 44 monitors the paging channel, under control by the receiver controlling circuit 49, for detecting the pilot PN code.
Specifically, the base station 1 transmits a paging message (paging channel) for the mobile unit 2 at a pre-set period, for example, at a period of 1.28 sec 2N, where N is not less than 1, as shown for example in Fig. 6A. For monitoring the paging channel, the receiver controlling circuit 49 starts the circuits absolutely necessary for monitoring the paging channel, such as the high-frequency amplifier 42, orthogonal detection circuit 43 or the PN detector 44, shortly before each reception slot, as shown in Fig.6B. The PN
detector 44 detects the pilot PN codes of the paging channel. The receiver control circuit 49 performs paging message processing, such as accepting the call, based on the paging message received from a decoder 48 as later explained. If no processing is required, the receiver control circuit 49 makes preparations for receiving the next paging channel and halts the previously started circuits 42, 43 and 44. q`he receiver is in operation intermittentlY
responsive to the intermittent transmission of the paging message of the base station 1 for lowering the power consumption.
Moreover, the PN detector 44 detects the PN code of the control channel from the HBS, under control by the receiver control 21 ~5399 circuit 49, in the interstitial~periods of detection of the pilot PN code of the above-descrLbed paging channel. Specifically, for receiving the control channel once per reception of one or more of the paging channel(s), the receiver control circuit 49 starts the circuits absolutely necessary for receiving the control channel, such as the high frequency amplifier 42, orthogonal detection circuit 43 or the PN detector 44, each time the paging channel(s) are received a pre-set number of times, as shown for example in Fig. 4D . The PN detector 44 detects the PN code of the control channel, while the recelver control circuit 49 switches between actuation of the mobile unit 2 under the HBS mode and actuation of the unit under the cellular mode, based on the identification information supplied from a decoder 48, as later explained, and halts the circuits started previouslY.
That is, the mobile unit 2 performs reception of the control channel from the HBS 3 once every plural interstitial periods, instead of performing such reception in all of the interstitial periods of paging channel reception from the HBS 3, thereby enabling the power consumption otherwise increased by control channel reception. Since the ~BS 3 transmits the control channel at a time interval shorter than the time period which elapses since the end of the paging channel until the leading end of the next paging channel, the control channel can be received reliably despite the fact that the control channel is received once eVerY
plural receptions by the mobile unit 2. Meanwhile, in the mobile ~ 2185399 unit 2, the receiver is: in operation during the period of transmission of the paging channel and during the period of transmis6ion of the control channel for monitoring the paging channel from the base station 1 and the control channel from the HBS 3, as gho~n in Figs.4B and 4D. However, if the control channel is received, the control .channel may be continuously received without transiently halting the receiver after the end of reception of the paging channel, as shown in Fig . 7C .
The demodulator 45. to 453 demodulate the baseband signals, using the pilot PN code or the PN code, and sends the resulting demodulated signal, such as signals corresponding to the data of the pilot channel, data of the sync channel, data of the paging channel and data of the traffics channel, or signals corresponding to data of the control channel from the HBS 3 or the data of the traffics channel, to the synthesizer 46 The synthesizer 46 synthesizes outputs of the demodulators 451 to 453 and converts the demodulated signal into bi-level signal by, for example, viterbi decoding. The resulting decoded data is supplied to a deinterleaver 47. SpecificalIy, there exist multiple paths in the radio transmission channel in general and the PN codes are detected at plural timings. Therefore, if there exist multiple paths, the receiver control circuit 49 actuates plural demodulators having PN
codes different in phase or timing for demodulation. The synthesizer 46 synthesizes the demodulated signals supplied from the demodulator 451 to 453 and generates decoded data from the demodulated signal improved in the S/N ratio.
The deinterleaver 47 and the decoder 48 are counterpart devices of the interleaving circuits 14, 17 and the encoding circuits 13, 16 of the BS 3, respectively. The deinterleaver 47 deinterleaves the decoded data supplied from the synthesizer 46, while the decoder 48 corrects the decoded data for errors and routes the error-corrected data to the receiver control circuit 49.
The receiver control circuit 49 controls the operating mode of the mobile unit 2 or the acceptance of the call, while transmitting the decoded data from the decoder 48 to a vocoder 50.
The vocoder 50 is associated with the encoder of the base station 1 or the BS 3 and decodes the received encoded speech data during talk while routing the resulting speech data via a terminal 51 to, for example, a digital/analog converter, not shown. The speech data is converted by the digital/analog converter into speech signals which are supplied to a speaker in order to permit the user to have a talk over the telephone.
Referring to Fig.8, an illustrative arrangement of the PN
detector 44 is axplained.
In Fig.8, the PN detector 44 has a correlation unit 61 for detecting the pilot PN code from the base station 1 or the PN code of a shorter period from the base station 3, and a signal strength decision circuit 62 for comparing the relation of correlation irom the correlation unit 61 to a pre-set threshold. The PN decoder also includes a PN code generator 63 for generating the pilot PN code . ~ 2~5399 or the PN code for routing the generated codes to the correlation unit 61 and a PN detector control circuit 64 for controlling the PN code generator 63.
The PN detector control circuit 64 manages control for varying the timing of the pilot PN code or the PN code based on the control signal which is supplied from the receiver control circuit 49 and which specifies the timing of the previously received pilot PN code or PN code.
The PN code generator 63 switches between the pilot PN code and the PN code, under cont~rol by the PN detector control circuit 64, and varies the timings of generation of these codes~
Referrlng to Fig.9, the PN code generator 63 includes a PN
generator 71 for generating the PN code which is the same as the pilot PN code transmitted by the base station 1, and a PN gener~tor 72 for generating the PN code which is the same as the PN code transmitted by the HBS 3. The PN code generated by PN generator 71 is also termed the pilot PN code. The PN code generator 63 also includes a timing controller 73 for controlling the PN generators 71, 72, and a selection circuit 74 for making switching selecticn between the pilot PN code from the PN generator 71 and the PN ccde from the PN generator 72.
The timing control circuit 73 controls the PN generators 71 and 72 based on the timing control signal supplied from the PN
detector control circuit 64 via a terminal 70. Thus the PN
generator 71 generates the pilot PN code based on the timing of the 2 ~ 85399 previously received pilot PN code, while the PN generator 72 generates the PN codes b~ased on the timing of the previously received PN code. The selection circuit 74 makes switching selection between the pilot PN code from the PN generator 71 and the PN code from the PN generator 72, based on the switching si~nal supplied from the PN detector control circuit 64 via a terminal 76, and routes the selected PN code to the correction unit 61 via a terminal 77. The PN generator not in use may be halted based on the switching signal.
The correlation unit 61 takes the correlation between the baseband reception signals supplied from the orthogonal detection circuit 43 via a terminal 65 and the pilot PN code from the PN code generator 63 and routes the results of correlation to the signal strength decision circuit 62.
The signal strength decision circuit 62 compares the result of correlation to a pre-set threshold value. If the result of correlation is larger than the threshold value, it is assumed that the pilot PN code or the PN code has been detected, and the result of detection is routed to the PN detector control circuit 64. The PN detector control circuit 64 roùtes the result of detection and the detection timing of the pilot PN code or the PN code via a terminal 67 to the receiver control circuit 49 (Fig.5). The receiver control circuit 49 controls the demodulators 451 to 453 (Fig.5) based on this timing while controlling the operational mode of the mobile unit 2 based on the results of detection. The ~ 2 1 8~39q receiver control circuit 49 routes the timing of the pilot PN code or the PN code to the PN detector control circuit 64 at the time of detection of the next pilot PN code or the PN code. That is, by detecting the PN code based on the timing of the previously received PN code, the PN code can be detected in a shorter time.
The above is the manner of detecting the PN code by the PN
detector 44. Since the HBS 3 detects the PN code, while the L~BS 3 routes the PN code having a period shorter than the period of the pilot PN signal from the base station 1, the PN detector 44 can detect the PN code in a shorter time. Stated differently, the preamble length of the control channel (control packet) can be shortened, so that, if the mobile unit Z is situated in proximity to the HBS 3 situated indoors, the mobile unit 2 can reliably receive the control channel from the HBS 3 during the Interstitial time periods of reception.of the paging channel.
Referring to Fig.ll, switching between the cellular mode and the LIBS mode will be explained. The receiver control circuit 49 controls the operationaL mode of the mobile unit 2.
At step Sl, the receiver control circuit 49 starts the operation of the receiver for receiving the L~aging channel from the base station 1 or the control channel from the HBS 3. The control circuit 49 then proceeds to step S2.
At step S2, the rec-eiver control circuit 49 receives the paging channel before proceeding to step S3.
At step S3, the receiver control circuit 49 judges whether or 2 f 85399 not a call has been accepted on the basis of the paging channel control in:~ormation (paging message) supplied from the decoder 48.
If the result of judgment at step S3 is YES, processing transfers to step S4 and, if otherwise, processing transfers to step S5.
At step S~, the receiver control circuit 49 increments the value of the counter storing the number of received p~ging channels before proceeding to step S6.
At step S6, the receiver control circuit 49 judges, based on the counter value, whether the timing is that of receiving the control channel. Ii' ~he result of judgment at step S6 is YES, processing transfers to step S7 and, if otherwise, processing transfers to step S11.
At step S7, the recaiver control circuit 49 receives the control channel from the E~BS 3 before proceeding to step S8.
At step S8, the receiver control circuit 49 judges, based on the identification in~ormation o:E the control channel supplied from the decoder 48, whether or not the HBS 3 is that associated with the mobile unit 2, as will be explained subsequently. If the result of judgment at step S8 is~ YES, the receiver control circuit 49 proceeds to step S9 and, if otherwise, the control circuit 49 proceeds to step S10.
At step S9, the receiver control circuit 49 sets the BBS mode, that is a mode of making a call and accepting a call via the ElBS
3.
At step S10, the receiver control circuit 49 initializes, that . ~ ~1 8~399 is zeroes, the above-mentioned counter, before proceeding to step At step S11, the receiver control circuit 49 judges whether the timing is that of receiving the next paging channel. If the result of judgment is YES, the receiver control circuit 49 proceeds to step S2 and, if= otherwise, the receiver control circuit reiterates step Sll.
At step S21 shown in Fig.11, the recelver control circuit 49 starts the operation of the receiver and initializes the receiver, such as by controlling the PN detector control circuit 64 for generating the PN code. The receiver control circuit 19 then proceeds to step S22.
At step S22, the receiver control circuit 49 starts the detection of the PN code from the HBS 3, before proceeding to step S23 .
At step S23, the receiver circuit 49 judges whether or not the PN code has been detected. If the result of judgment at step S23 is YES, the control circuit proceeds to step S24 and, if otherwise, to step S28.
At step S24, the receiver control circuit 49 makes control operations, such as demodulation by the demodulators 4~1 to 453, using the PN code, before proceeding to step S2~.
At step S2~, the receiver control circuit 49 judges whether or not reception of a control message such as the control information, has come to a close. If the result of judgment at 21 8~399 . ~
step S25 is YES, the control circuit 49 proceeds to 5tep S26 and, if otherwise, to step S29.
At step S26, the receiver control circuit 49 decides whether or not the identification information ID supplied from the decoder 48 is its own identification information ID. If the result of judgment is YES, the receiver control circuit 49 proceeds to step S27 and otherwise to step S30.
At step S27, the receiver control circuit 49 sets a detection flag indicating that the associated HBS 3 has been confirmed.
At step S28, the receiver control circuit 9 judges whether or not the time period in which to receive the eontrol channel has elapsed. If the result of judgment at step S28 is YES, the reeeiver eontrol circuit 49 proeeeds to step S30 and, if otherwise, the reeeiver eontrol eircuit reverts to S25.
At step S30, the receiver control eireuit 49 sets a non-deteetion flag specifying that the associated HBS 3 has not been identified .
That is, at step S7 of Fig.10, the reeeiver control eireuit 49 sets the detection flag or the non-detected flag, and deteets the HBS 3 at step S8 based on these flags.
It will be seen from the foregoing that, with the mobile eommunieation system aeeording to the present invention, the HBS
3 eonneeted to the subseriber network transmits N periods of the PN eode having a period shorter than that of the pilot PN eode sent from the base station 1 and th; identifieation information for 2 ~ 85399 identifying the respectiYe home base stations 3, as the control ch~nnel. If, based on the identiiication information of the control channel received from the BS 3, ~he mobile unit 2 can identify the pertinent ~BS, it makes a call or accepts a call via the BS 3. If otherwise, the mobile unit 2 makes a call or accepts a call via the base station 1. Thus the mobile unit 2 can receive the control channel from the BS 3 in a short time.
Moreover, since the HBS 3 transmits the control channel in a time duration shorter than the time interval which elapses since the end of the paging channel intermittently transmitted i:'rom the base station 1 until the leading end of the next paging channel, it becomes possible for the mobile unit 2 to receive the control channel in the interstitial period between the reception operations of the paging channel.
Since the BS 3 varies the timing of transmission of the control channel based on the random number, it becomes possible to prevent continuous collision of a control packet transmitted by other home base stations in operation with a control packet transmitted by the BS 3.
In addition, since the mobile unit 2 intermittently receives the paging channel transmitted by the base station 1, while receiving the control channel from ~he BS 3 during the period in which it is not receiving the paging channel, the mobile station 2 can receive the control channel from the ~BS 3 reliably, while it becomes possible to reduce power consumption.
2 ~ ~5399 . ~
Since the mobile unit 2 receives the control channel each time i t receives plural pagin~ channels, the power consumption can be reduced correspondingly.
The present invention is not limited to the above-described embodiments. For example, the plural home base stations 3 can transmit control channels of respective different PN codes. In such case, the mobile unit 2 can identlfy the pertinent ED3S by referring to the PN code of the control channel.
.
being not less than 1, of the PN code having a period shorter than that of the pilot PN code transmitted from the base station 1, and the identification information for identifying the HBS, as a control channel. The mobile unit 2 is resPOnsive to the identification information for the control channel received from the HBS 3 to make a call or ~accept a call via the HBS 3 if the HBS
3 has been identified to be its o~n HBS. If other~ise, the mobile unit makes a cal or accepts a call via the base station 1.
With the mobile communication system, the mobile unit 2 situated in an area capable of having communication with the BS
3 situated indoors can be used as a slave unit of the so-called cordless telephone. At this time, the mobile unit 2 operates under an HBS mode of making or accepting a call via HBS 3 equivalent to the master unit connected to the subscriber network. If the mobile unit 2 is situated in an are ncapable of having communication .` 21 85399 with the HBS3, it operates under a cellular mode of making or accepting a call via the base station 1.
Ei'ig.3 shows an example: of the constitution of a transmission system of the BS 3. T~e HBS 3 includes a transmission data generating circuit 11 for outputting the encoded speech data in a pre-set format and a control circuit 12 for generating the identification information for identifying the home base stations 3. The HBS 3 also includes a control pacl~et generating circuit 15 for outputting the identification from the control circuit 12 in a pre-set format and a PN code generator for generating a PN code having a period shorter than that of the pilot PN code of the paging channel transmitted from the base station. The HBS 3 also includes a plurality of, herein three, Walsh code generators 22 to 24 for generating respectively different Walsh codes and multiplier~s 25 to 27 for multiplying the PN codes from the PN code generator 21 with the Walsh codes from the Walsh code generators 22 to 24. The HBS 3 also includes a multiplier 28 for multiplYing the identification information generated by the control circuit 12 with an output of the multiplier 26 and a multiplier 29 for multiplying the speech data outputted by the transmissLon data generating circuit 11 with an output of the multiplier 27. The HBS
3 additionally includes an adder 30 for summing outputs of the multipliers 25, 28, 29 and a modulator 31 for modulating an output of the channel adder 30 in :accordance with a pre-set modulation system. The BS 3 further includ s a high freouency ampli/ier 32 . . 2185399 for amplifying the modulated signal from the modulator 31 and an antenna 33.
When a call has been accepted via subscriber network, the control circuit 12 generat~es the control information for network control, such as calling responsive to accepted call, while generating the identificatiDn information for identification of the respective home base stations allocated to the home base stations 3 at a time interval shorter than the time duration as from the end of a paging channel intermittently transmitted from the base station 1 until the leading end of the next paging channel. This control information is supplied to the transmission data generating circuit 11, while the identification information is supplicd to the control packet generating circuit 15.
During telephone talk, the transmission data generating circuit 11 is fed via a terminal 18 with speech data encoded by a pre-set coding rule (encoded speech data). The transmission data generating circuit 11 converts the encoded speech data and the control information for network control supplied from the control circuit 12, and routes the resulting format-converted data to a encoding circuit 13. The encoding circuit 13 encodes the format-converted encoded speech data using, for example, convolutional codes for making error correction in the mobile unit Z. An interleaving circuit 14 interleaves the ended speech data so that no burst error will be produced in the encoded speech data, and routes the encoded speech dat. to the multiplier 29.
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On the other hand, the control packet generating circuit 15 converts the identLfication information proper to the HBS 3 and routes the resulting packet to an encoding circuit 16. Similarly to the encoding circuit 13, the encoding circuit 16 encodes the identification information. Likewise, the interleaving circuit 17 interleaves the encoded identification ini~ormation, as in the case of the interleaving circuit 14, and routes the resulting interleaved encoded identification information to the multiplier 28 .
The PN code generator 21 generates the PN code with a period e~ual to, for e2~ample, 2~, which is shorter than the time which elapses since the end of the paging channel intermittently transmitted from the base station 1 until the lading end of the next paging channel, and sends the PN code to the multipliers 25 to 27.
The Walsh code generator 22 generates the Walsh codes O, i.e., all-zero, which is the orthogonal code. The multiplier 25 multiplies the Walsh code O with the PN code supplied from the PN
generator 21 and routes the resulting code to the channel adder 30.
The Walsh code generator 23 generates Walsh codes m, where m is a pre-selected integer from 1 to 63. The multiplier 26 multiplies the Walsh codes m with the PN code supplied from the PN
generator 21 and sends the resulting product data to the multiplier 28. The multiplier 28 is fed with the interleaved identiiication information from the interleaving circuit 17. The multiplier ~ . ~1 85399 multiplies the identification code with and output of the multiplier 26 and routes the resulting data to the channel adder 30 .
The Walsh code generator 24 generates Walsh codes k, where k is a pre-selected integer from 1 to 63. The multiplier 27 multiplies the Walsh codes k with the PN code supplied from the PN
generator 21 and sends the resulting product data to the multiplier 29. The multiplier 28 is fed with the interleaved identification information from the interleaving circuit 1~. The multiplier multiplies the identification code with an output of the multiplier 26 and routes the resulting data to the channel adder 30.
The channel adder 30 sums the outputs of the multipliers 25, 28, 29 and routes the resulting sum data as the transmission data to the modulator 31. Specifically, the channel adder 30 is continuously fed from the base station 1 with a paging message (paging channel) containing the pilot PN code having a period of 1.28 sec 2N, where N is not less than 1, as shown for example in Fig.4A. The channel adder 30 forms a control channel made up of a preamble containing the PN code and data containing the identification information, while outputting this control channel as a control packet at a period shorter than the period of the paging message. The transmission timing of the control packet (control channel) may be varied on the basis of random numbers for avoiding continuous collision of the control packets sent from the other home base station agaln~t ~e control packet transmitted by ~ 21 8~399 the HBS 3.
The modulator 31 is comprised of pre-set modulators, for example, a two-phase phase shift keying (PSK) modulator or a Quadrature phase shift keying (QPSK) modulator, and modulates two carrier waves having phase shift of ,~/2 from each other with the control channel supplied form the channel adder 30 and with encoded speech data if the mobile unit is belng used for talk. The resulting modulated signal is supplied to a high freQuency amplifier 32 which then amplifies the modulated signal and sends the amplified signal via antenna 33 to the high frequencY amplifier 32. Thus the BS 3 transmits the control channel at least once during the time since the end of the paging channel intermittently transmitted from the base station 1 until the leading end of the next paging channel.
l~eferring now to Fig.5, an illustrative structure of the mobile unit 2 is explained.
In Fig.5, the mobile unit 2 has, as its receiving portions, an antenna 41 for receivlng modulated signals from the base station 1 and the EIBS 3, and a high frequency amplifier 42 received by the antenna 41. The mobile unit 2 also includes an orthogonal detection circuit 43 for converting the high-freQuency modulated signal for converting the detected signal into the base-band signal and a PN detection unit 44 for detecting the pilot PN code from the base station 1 and the PN code from the HBS 3. The mobile unit 2 also includes a plurality of, herein three, demodulators 451, 45 ` ` 21 85399 and 45~ for demodulating the baseband signal from the orthogonal detection circuit 43 and a synthesis unit 46 for synthesizing the outputs of the demodulators 451 to 45~. The mobile unit 2 also includes a deinterleaver 47 for deinterleaving the decoded data and a decoder 48 for error-correcting the decoding data. The mobile unit 2 finally includes a receiver control circuit 49 controlling the PN detector 44 and so forth, and= a vocoder 50 for reproducing speech data.
In a so-called idling~state, the mobile unit 2 receives the paging channel from the base: station 1, while receiving the control channel from the HBS 3 in :the interstitial periods between the times of reception of the paging channel. If the mobile unit 2 has succeeded in identifying its own BS 3, it operates in the BS mode of making a call or accepting a call via this EBS 3, and otherwise operates in the cellular mode of making a call or accepting a call via the base station 1. Stated differently, the mobile unit 2 operates :~s a slave unit of the cordless telephone in an area capable of having telephone communic~tion with, for example, an indoor BS 3, that is, it makes a call or accepts a call via an HBS
3 connected to the subscriber network. In an area incapable of having telephone communication, the mobile unit 2 operates as a mobile terminal making a cal~ and accepting a call via the base station l.
Specifically, the high frequency amplifier 42 amplifies the modulated signal, received over an antenna 41, while the orthogonal 2f ~5399 detection circuit 43 orthogonally detects the modulated signal and routes the resulting base-band signal to the PN detector 44 and to the amplifiers 45~ to 45~.
In the idling state of the receiver of the mobile unit 2, the PN detector 44 monitors the paging channel, under control by the receiver controlling circuit 49, for detecting the pilot PN code.
Specifically, the base station 1 transmits a paging message (paging channel) for the mobile unit 2 at a pre-set period, for example, at a period of 1.28 sec 2N, where N is not less than 1, as shown for example in Fig. 6A. For monitoring the paging channel, the receiver controlling circuit 49 starts the circuits absolutely necessary for monitoring the paging channel, such as the high-frequency amplifier 42, orthogonal detection circuit 43 or the PN detector 44, shortly before each reception slot, as shown in Fig.6B. The PN
detector 44 detects the pilot PN codes of the paging channel. The receiver control circuit 49 performs paging message processing, such as accepting the call, based on the paging message received from a decoder 48 as later explained. If no processing is required, the receiver control circuit 49 makes preparations for receiving the next paging channel and halts the previously started circuits 42, 43 and 44. q`he receiver is in operation intermittentlY
responsive to the intermittent transmission of the paging message of the base station 1 for lowering the power consumption.
Moreover, the PN detector 44 detects the PN code of the control channel from the HBS, under control by the receiver control 21 ~5399 circuit 49, in the interstitial~periods of detection of the pilot PN code of the above-descrLbed paging channel. Specifically, for receiving the control channel once per reception of one or more of the paging channel(s), the receiver control circuit 49 starts the circuits absolutely necessary for receiving the control channel, such as the high frequency amplifier 42, orthogonal detection circuit 43 or the PN detector 44, each time the paging channel(s) are received a pre-set number of times, as shown for example in Fig. 4D . The PN detector 44 detects the PN code of the control channel, while the recelver control circuit 49 switches between actuation of the mobile unit 2 under the HBS mode and actuation of the unit under the cellular mode, based on the identification information supplied from a decoder 48, as later explained, and halts the circuits started previouslY.
That is, the mobile unit 2 performs reception of the control channel from the HBS 3 once every plural interstitial periods, instead of performing such reception in all of the interstitial periods of paging channel reception from the HBS 3, thereby enabling the power consumption otherwise increased by control channel reception. Since the ~BS 3 transmits the control channel at a time interval shorter than the time period which elapses since the end of the paging channel until the leading end of the next paging channel, the control channel can be received reliably despite the fact that the control channel is received once eVerY
plural receptions by the mobile unit 2. Meanwhile, in the mobile ~ 2185399 unit 2, the receiver is: in operation during the period of transmission of the paging channel and during the period of transmis6ion of the control channel for monitoring the paging channel from the base station 1 and the control channel from the HBS 3, as gho~n in Figs.4B and 4D. However, if the control channel is received, the control .channel may be continuously received without transiently halting the receiver after the end of reception of the paging channel, as shown in Fig . 7C .
The demodulator 45. to 453 demodulate the baseband signals, using the pilot PN code or the PN code, and sends the resulting demodulated signal, such as signals corresponding to the data of the pilot channel, data of the sync channel, data of the paging channel and data of the traffics channel, or signals corresponding to data of the control channel from the HBS 3 or the data of the traffics channel, to the synthesizer 46 The synthesizer 46 synthesizes outputs of the demodulators 451 to 453 and converts the demodulated signal into bi-level signal by, for example, viterbi decoding. The resulting decoded data is supplied to a deinterleaver 47. SpecificalIy, there exist multiple paths in the radio transmission channel in general and the PN codes are detected at plural timings. Therefore, if there exist multiple paths, the receiver control circuit 49 actuates plural demodulators having PN
codes different in phase or timing for demodulation. The synthesizer 46 synthesizes the demodulated signals supplied from the demodulator 451 to 453 and generates decoded data from the demodulated signal improved in the S/N ratio.
The deinterleaver 47 and the decoder 48 are counterpart devices of the interleaving circuits 14, 17 and the encoding circuits 13, 16 of the BS 3, respectively. The deinterleaver 47 deinterleaves the decoded data supplied from the synthesizer 46, while the decoder 48 corrects the decoded data for errors and routes the error-corrected data to the receiver control circuit 49.
The receiver control circuit 49 controls the operating mode of the mobile unit 2 or the acceptance of the call, while transmitting the decoded data from the decoder 48 to a vocoder 50.
The vocoder 50 is associated with the encoder of the base station 1 or the BS 3 and decodes the received encoded speech data during talk while routing the resulting speech data via a terminal 51 to, for example, a digital/analog converter, not shown. The speech data is converted by the digital/analog converter into speech signals which are supplied to a speaker in order to permit the user to have a talk over the telephone.
Referring to Fig.8, an illustrative arrangement of the PN
detector 44 is axplained.
In Fig.8, the PN detector 44 has a correlation unit 61 for detecting the pilot PN code from the base station 1 or the PN code of a shorter period from the base station 3, and a signal strength decision circuit 62 for comparing the relation of correlation irom the correlation unit 61 to a pre-set threshold. The PN decoder also includes a PN code generator 63 for generating the pilot PN code . ~ 2~5399 or the PN code for routing the generated codes to the correlation unit 61 and a PN detector control circuit 64 for controlling the PN code generator 63.
The PN detector control circuit 64 manages control for varying the timing of the pilot PN code or the PN code based on the control signal which is supplied from the receiver control circuit 49 and which specifies the timing of the previously received pilot PN code or PN code.
The PN code generator 63 switches between the pilot PN code and the PN code, under cont~rol by the PN detector control circuit 64, and varies the timings of generation of these codes~
Referrlng to Fig.9, the PN code generator 63 includes a PN
generator 71 for generating the PN code which is the same as the pilot PN code transmitted by the base station 1, and a PN gener~tor 72 for generating the PN code which is the same as the PN code transmitted by the HBS 3. The PN code generated by PN generator 71 is also termed the pilot PN code. The PN code generator 63 also includes a timing controller 73 for controlling the PN generators 71, 72, and a selection circuit 74 for making switching selecticn between the pilot PN code from the PN generator 71 and the PN ccde from the PN generator 72.
The timing control circuit 73 controls the PN generators 71 and 72 based on the timing control signal supplied from the PN
detector control circuit 64 via a terminal 70. Thus the PN
generator 71 generates the pilot PN code based on the timing of the 2 ~ 85399 previously received pilot PN code, while the PN generator 72 generates the PN codes b~ased on the timing of the previously received PN code. The selection circuit 74 makes switching selection between the pilot PN code from the PN generator 71 and the PN code from the PN generator 72, based on the switching si~nal supplied from the PN detector control circuit 64 via a terminal 76, and routes the selected PN code to the correction unit 61 via a terminal 77. The PN generator not in use may be halted based on the switching signal.
The correlation unit 61 takes the correlation between the baseband reception signals supplied from the orthogonal detection circuit 43 via a terminal 65 and the pilot PN code from the PN code generator 63 and routes the results of correlation to the signal strength decision circuit 62.
The signal strength decision circuit 62 compares the result of correlation to a pre-set threshold value. If the result of correlation is larger than the threshold value, it is assumed that the pilot PN code or the PN code has been detected, and the result of detection is routed to the PN detector control circuit 64. The PN detector control circuit 64 roùtes the result of detection and the detection timing of the pilot PN code or the PN code via a terminal 67 to the receiver control circuit 49 (Fig.5). The receiver control circuit 49 controls the demodulators 451 to 453 (Fig.5) based on this timing while controlling the operational mode of the mobile unit 2 based on the results of detection. The ~ 2 1 8~39q receiver control circuit 49 routes the timing of the pilot PN code or the PN code to the PN detector control circuit 64 at the time of detection of the next pilot PN code or the PN code. That is, by detecting the PN code based on the timing of the previously received PN code, the PN code can be detected in a shorter time.
The above is the manner of detecting the PN code by the PN
detector 44. Since the HBS 3 detects the PN code, while the L~BS 3 routes the PN code having a period shorter than the period of the pilot PN signal from the base station 1, the PN detector 44 can detect the PN code in a shorter time. Stated differently, the preamble length of the control channel (control packet) can be shortened, so that, if the mobile unit Z is situated in proximity to the HBS 3 situated indoors, the mobile unit 2 can reliably receive the control channel from the HBS 3 during the Interstitial time periods of reception.of the paging channel.
Referring to Fig.ll, switching between the cellular mode and the LIBS mode will be explained. The receiver control circuit 49 controls the operationaL mode of the mobile unit 2.
At step Sl, the receiver control circuit 49 starts the operation of the receiver for receiving the L~aging channel from the base station 1 or the control channel from the HBS 3. The control circuit 49 then proceeds to step S2.
At step S2, the rec-eiver control circuit 49 receives the paging channel before proceeding to step S3.
At step S3, the receiver control circuit 49 judges whether or 2 f 85399 not a call has been accepted on the basis of the paging channel control in:~ormation (paging message) supplied from the decoder 48.
If the result of judgment at step S3 is YES, processing transfers to step S4 and, if otherwise, processing transfers to step S5.
At step S~, the receiver control circuit 49 increments the value of the counter storing the number of received p~ging channels before proceeding to step S6.
At step S6, the receiver control circuit 49 judges, based on the counter value, whether the timing is that of receiving the control channel. Ii' ~he result of judgment at step S6 is YES, processing transfers to step S7 and, if otherwise, processing transfers to step S11.
At step S7, the recaiver control circuit 49 receives the control channel from the E~BS 3 before proceeding to step S8.
At step S8, the receiver control circuit 49 judges, based on the identification in~ormation o:E the control channel supplied from the decoder 48, whether or not the HBS 3 is that associated with the mobile unit 2, as will be explained subsequently. If the result of judgment at step S8 is~ YES, the receiver control circuit 49 proceeds to step S9 and, if otherwise, the control circuit 49 proceeds to step S10.
At step S9, the receiver control circuit 49 sets the BBS mode, that is a mode of making a call and accepting a call via the ElBS
3.
At step S10, the receiver control circuit 49 initializes, that . ~ ~1 8~399 is zeroes, the above-mentioned counter, before proceeding to step At step S11, the receiver control circuit 49 judges whether the timing is that of receiving the next paging channel. If the result of judgment is YES, the receiver control circuit 49 proceeds to step S2 and, if= otherwise, the receiver control circuit reiterates step Sll.
At step S21 shown in Fig.11, the recelver control circuit 49 starts the operation of the receiver and initializes the receiver, such as by controlling the PN detector control circuit 64 for generating the PN code. The receiver control circuit 19 then proceeds to step S22.
At step S22, the receiver control circuit 49 starts the detection of the PN code from the HBS 3, before proceeding to step S23 .
At step S23, the receiver circuit 49 judges whether or not the PN code has been detected. If the result of judgment at step S23 is YES, the control circuit proceeds to step S24 and, if otherwise, to step S28.
At step S24, the receiver control circuit 49 makes control operations, such as demodulation by the demodulators 4~1 to 453, using the PN code, before proceeding to step S2~.
At step S2~, the receiver control circuit 49 judges whether or not reception of a control message such as the control information, has come to a close. If the result of judgment at 21 8~399 . ~
step S25 is YES, the control circuit 49 proceeds to 5tep S26 and, if otherwise, to step S29.
At step S26, the receiver control circuit 49 decides whether or not the identification information ID supplied from the decoder 48 is its own identification information ID. If the result of judgment is YES, the receiver control circuit 49 proceeds to step S27 and otherwise to step S30.
At step S27, the receiver control circuit 49 sets a detection flag indicating that the associated HBS 3 has been confirmed.
At step S28, the receiver control circuit 9 judges whether or not the time period in which to receive the eontrol channel has elapsed. If the result of judgment at step S28 is YES, the reeeiver eontrol circuit 49 proeeeds to step S30 and, if otherwise, the reeeiver eontrol eircuit reverts to S25.
At step S30, the receiver control eireuit 49 sets a non-deteetion flag specifying that the associated HBS 3 has not been identified .
That is, at step S7 of Fig.10, the reeeiver control eireuit 49 sets the detection flag or the non-detected flag, and deteets the HBS 3 at step S8 based on these flags.
It will be seen from the foregoing that, with the mobile eommunieation system aeeording to the present invention, the HBS
3 eonneeted to the subseriber network transmits N periods of the PN eode having a period shorter than that of the pilot PN eode sent from the base station 1 and th; identifieation information for 2 ~ 85399 identifying the respectiYe home base stations 3, as the control ch~nnel. If, based on the identiiication information of the control channel received from the BS 3, ~he mobile unit 2 can identify the pertinent ~BS, it makes a call or accepts a call via the BS 3. If otherwise, the mobile unit 2 makes a call or accepts a call via the base station 1. Thus the mobile unit 2 can receive the control channel from the BS 3 in a short time.
Moreover, since the HBS 3 transmits the control channel in a time duration shorter than the time interval which elapses since the end of the paging channel intermittently transmitted i:'rom the base station 1 until the leading end of the next paging channel, it becomes possible for the mobile unit 2 to receive the control channel in the interstitial period between the reception operations of the paging channel.
Since the BS 3 varies the timing of transmission of the control channel based on the random number, it becomes possible to prevent continuous collision of a control packet transmitted by other home base stations in operation with a control packet transmitted by the BS 3.
In addition, since the mobile unit 2 intermittently receives the paging channel transmitted by the base station 1, while receiving the control channel from ~he BS 3 during the period in which it is not receiving the paging channel, the mobile station 2 can receive the control channel from the ~BS 3 reliably, while it becomes possible to reduce power consumption.
2 ~ ~5399 . ~
Since the mobile unit 2 receives the control channel each time i t receives plural pagin~ channels, the power consumption can be reduced correspondingly.
The present invention is not limited to the above-described embodiments. For example, the plural home base stations 3 can transmit control channels of respective different PN codes. In such case, the mobile unit 2 can identlfy the pertinent ED3S by referring to the PN code of the control channel.
.
Claims (22)
- Claim 1. A method for mobile transmission for having communication between a base station and a plurality of mobile units by a code division multiple connection system, there being a plurality of fixed stations connected to the subscriber network in association with said mobile units, wherein N periods of the PN codes shorter in period than a pilot PN code transmitted from the base station, N being not less than 1, and the identification information for identifying the fixed stations, are transmitted as a control channel; and wherein, if a fixed station has been confirmed by said mobile unit to be the fixed station associated with the mobile unit, based on the identification information of the control channel received by the fixed station, a call is made or accepted via said fixe station and, if otherwise, a call is made or accepted via said base station.
- Claim 2. The method for mobile communication as claimed in claim 1 wherein said fixed station transmits said control channel in a time interval shorter than the time which elapses since the end of a paging channel intermittently transmitted from the base station until the leading end of the next paging channel.
- Claim 3. The method for mobile communication as claimed in claim 1 wherein said fixed station varies the timing of transmitting the control channel based on random numbers.
- Claim 4. The method for mobile communication as claimed in claim 1 wherein said mobile unit intermittently receives the paging channel transmitted from the base station, and wherein the control channel from the fixed station is received during the period of not receiving the paging channel.
- Claim 5. The method for mobile communication as claimed in claim 4 wherein said mobile unit receives said control channel each time it receives plural paging channels.
- Claim 6. The method for mobile communication as claimed in claim 1 wherein said plurality of fixed stations transmit control channels of respectively different PN codes.
- Claim 7. A system for mobile transmission for having communication between a base station and a plurality of mobile units by a code division multiple connection system, comprising: a plurality of fixed stations for transmitting N periods of the a PN code shorter in period than a pilot PN code transmitted from the base station, as a control channel, N being not less than 1, and for transmitting the identification information for identifying the fixed stations, as a control channel, said fixed stations being associated with said mobile units and being connected to a subscriber network; and a plurality of mobile units which, if a fixed station has been confirmed by said mobile unit to be the fixed station associated with the mobile unit, based on the identification information of the control channel received by the fixed station, makes or accepts a call via said fixe station and, if otherwise, makes or accepts a call via said base station.
- Claim 8. The system for mobile communication as claimed in claim 7 wherein said fixed station transmits said control channel in a time interval shorter than the time which elapses since the end of the paging channel intermittently transmitted from said base station until the leading end of the next paging channel.
- Claim 9. The system for mobile communication as claimed in claim 7 wherein said fixed station varies the timing of transmitting the control channel based on random numbers.
- Claim 10. The system for mobile communication as claimed in claim 7 wherein said mobile unit intermittently receives the paging channel intermittently transmitted from the base station, said mobile unit receiving the control channel from the fixed station during a period of not receiving the paging channel.
- Claim 11. The apparatus for mobile communication as claimed in claim 10 wherein said mobile unit receives said control channel each time it receives a plurality of said paging channels.
- Claim 12. The apparatus for mobile communication as claimed in claim 7 wherein said fixed stations transmit control channels of respectively different PN codes.
- Claim 13. A fixed station in a mobile communication system designed for having communication between a base station and a plurality of mobile units by a code division multiple connection system, said fixed station having radio communication with said mobile unit, comprising:
PN code generating means for generating a PN code shorter in period than a pilot PN code transmitted from the base station;
identification information generating means for generating the identification information for identifying the fixed stations; and control channel transmitting means for transmitting N periods of the PN code from said PN code generating means, N being not less than 1, and the identification information from said identification information generating means, as a control channel. - Claim 14. The fixed station as claimed in claim 13 wherein the fixed station transmits said control channel in a time interval shorter than the time which elapses since the end of the paging channel intermittently transmitted from said base station until the leading end of the next paging channel.
- Claim 15. The fixed station as claimed in claim 13 wherein the control channel transmitting means varies the timing of transmitting the control channel based on random numbers.
- Claim 16. The fixed station as claimed in claim 13 wherein said PN code generating means generates the PN code different from one fixed station to another.
- Claim 17. A mobile unit in a mobile communication system in which communication is had between a base station and a plurality of the mobile units by a code division multiple connection system, comprising:
reception means for receiving a paging channel from said base station and for receiving N periods, N being not less than 1, of PN codes shorter in period than a pilot PN code, and the identification information for identifying a plurality of fixed stations associated with the mobile units as a control channel;
PN code detection means for detecting the PN codes of the control channel received by said reception means;
demodulation means for demodulating the identification information of said control channel based on the result of detection of said PN code detection means; and control means managing control for making a call or accepting a call via a fixed station if the fixed station has been confirmed by said mobile unit to be the fixed station associated with the mobile unit based on the identification information from the demodulation means, said control means managing control for making or accepting a call via said base station otherwise. - Claim 18. The mobile unit as claimed in claim 17 wherein said fixed station transmits said control channel in a time interval shorter than the time which elapses since the end of the paging channel intermittently transmitted from said base station until the leading end of the next paging channel;
said control means controlling said PN code detection means for detecting the PN code of said control channel. - Claim 19. The mobile unit as claimed in claim 17 wherein said fixed station varies the timing of transmission of the control channel based on random numbers, and wherein said control means controls the PM code detection means for detecting the PN code of said control channel.
- Claim 20. The mobile unit as claimed in claim 17 wherein said control means controls said reception means so that said reception means receives the paging channel intermittently transmitted from the base station, and so that said reception means receives the control channel from said base station during the period of not receiving the paging channel.
- Claim 21. The mobile unit as claimed in claim 20 wherein said control unit controls said mobile unit for receiving said control channel each time it receives plural paging channels.
- Claim 22. The mobile unit as claimed in claim 17 wherein said fixed station transmits control channels of the respectively different PN codes and wherein said PN code detection means detects only the PN code allocated to an associated fixed station.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7266402A JPH0993652A (en) | 1995-09-20 | 1995-09-20 | Mobile communication method and mobile communication system |
| JPP07-266402 | 1995-09-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2185399A1 true CA2185399A1 (en) | 1997-03-21 |
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ID=17430438
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002185399A Abandoned CA2185399A1 (en) | 1995-09-20 | 1996-09-12 | Mobile communication method and system |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5812543A (en) |
| JP (1) | JPH0993652A (en) |
| KR (1) | KR970019200A (en) |
| CN (1) | CN1094703C (en) |
| CA (1) | CA2185399A1 (en) |
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| JP3575649B2 (en) * | 1996-04-02 | 2004-10-13 | ソニー株式会社 | Pilot signal detection method, pilot signal detection device and receiving device |
| US6678311B2 (en) | 1996-05-28 | 2004-01-13 | Qualcomm Incorporated | High data CDMA wireless communication system using variable sized channel codes |
| US6021122A (en) * | 1996-06-07 | 2000-02-01 | Qualcomm Incorporated | Method and apparatus for performing idle handoff in a multiple access communication system |
| KR19980065977A (en) * | 1997-01-17 | 1998-10-15 | 구자홍 | Code Division Multiple Access System for Indoor / Outdoor Operation |
| US6195642B1 (en) * | 1997-04-15 | 2001-02-27 | Sony Corporation | Digital broadcasting receiving apparatus |
| US6081536A (en) | 1997-06-20 | 2000-06-27 | Tantivy Communications, Inc. | Dynamic bandwidth allocation to transmit a wireless protocol across a code division multiple access (CDMA) radio link |
| US6542481B2 (en) | 1998-06-01 | 2003-04-01 | Tantivy Communications, Inc. | Dynamic bandwidth allocation for multiple access communication using session queues |
| US6873612B1 (en) * | 1997-10-30 | 2005-03-29 | Nortel Networks Limited | Methods and devices for asynchronous operation of a CDMA mobile communication system |
| US9118387B2 (en) | 1997-11-03 | 2015-08-25 | Qualcomm Incorporated | Pilot reference transmission for a wireless communication system |
| US6574211B2 (en) * | 1997-11-03 | 2003-06-03 | Qualcomm Incorporated | Method and apparatus for high rate packet data transmission |
| US7184426B2 (en) | 2002-12-12 | 2007-02-27 | Qualcomm, Incorporated | Method and apparatus for burst pilot for a time division multiplex system |
| US7394791B2 (en) | 1997-12-17 | 2008-07-01 | Interdigital Technology Corporation | Multi-detection of heartbeat to reduce error probability |
| US9525923B2 (en) | 1997-12-17 | 2016-12-20 | Intel Corporation | Multi-detection of heartbeat to reduce error probability |
| US6222832B1 (en) * | 1998-06-01 | 2001-04-24 | Tantivy Communications, Inc. | Fast Acquisition of traffic channels for a highly variable data rate reverse link of a CDMA wireless communication system |
| US6018547A (en) * | 1998-01-09 | 2000-01-25 | Bsd Broadband, N.V. | Method and apparatus for increasing spectral efficiency of CDMA systems using direct sequence spread spectrum signals |
| US6198732B1 (en) | 1998-03-13 | 2001-03-06 | Lucent Technologies Inc. | Forward-link traffic/paging-channel interleaving for communication systems based on closed-form expressions |
| US6198733B1 (en) * | 1998-03-13 | 2001-03-06 | Lucent Technologies Inc. | Forward-link sync-channel interleaving/de-interleaving for communication systems based on closed-form expressions |
| US6195344B1 (en) | 1998-03-13 | 2001-02-27 | Lucent Technologies Inc. | Forward-link traffic/paging-channel de-interleaving for communication systems based on closed-form expressions |
| US6295287B1 (en) | 1998-03-13 | 2001-09-25 | Agere System Guardian Corp. | Reverse-link interleaving for communication systems based on closed-form expressions |
| US6185200B1 (en) | 1998-03-13 | 2001-02-06 | Lucent Technologies Inc. | Reverse-link de-interleaving for communication systems based on closed-form expressions |
| US6748010B1 (en) * | 1998-10-13 | 2004-06-08 | Qualcomm Incorporated | Combined searching and page monitoring using offline sample storage |
| US6721349B1 (en) | 1999-01-28 | 2004-04-13 | Qualcomm Incorporated | Method and apparatus for reducing peak-to-average ratio in a CDMA communication system |
| US6873647B1 (en) * | 1999-02-26 | 2005-03-29 | Qualcomm Incorporated | Method and system for reducing synchronization time in a CDMA wireless communication system |
| KR100450791B1 (en) * | 1999-07-13 | 2004-10-01 | 삼성전자주식회사 | CDMA demodulating method and demodulator |
| JP2001156749A (en) * | 1999-09-17 | 2001-06-08 | Hitachi Kokusai Electric Inc | Cdma mobile station device |
| US6549779B1 (en) * | 2000-01-17 | 2003-04-15 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and system for improving the performance of inter-systems handovers |
| US6973098B1 (en) | 2000-10-25 | 2005-12-06 | Qualcomm, Incorporated | Method and apparatus for determining a data rate in a high rate packet data wireless communications system |
| US7068683B1 (en) | 2000-10-25 | 2006-06-27 | Qualcomm, Incorporated | Method and apparatus for high rate packet data and low delay data transmissions |
| US7940833B2 (en) * | 2006-06-21 | 2011-05-10 | Telefonaktiebolaget Lm Ericsson (Publ) | Transmitter with intelligent preconditioning of amplifier signal |
| US7787885B1 (en) * | 2006-08-10 | 2010-08-31 | Nextel Communications Inc. | Walsh code expansion in wireless communications systems |
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| US20090061858A1 (en) * | 2007-08-31 | 2009-03-05 | Samsung Electronics Co., Ltd. | System and Method to Manage Communication Handoff |
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| US5127042A (en) * | 1988-09-23 | 1992-06-30 | Motorola, Inc. | Cellular cordless telephone |
| GB2282730B (en) * | 1993-10-08 | 1998-01-28 | Nokia Telecommunications Oy | Dual mode subscriber terminal and a handover procedure of the dual mode subscriber terminal in a mobile telecommunication network |
| US5574976A (en) * | 1994-05-06 | 1996-11-12 | Motorola, Inc. | System for scanning channels |
-
1995
- 1995-09-20 JP JP7266402A patent/JPH0993652A/en not_active Withdrawn
-
1996
- 1996-09-12 CA CA002185399A patent/CA2185399A1/en not_active Abandoned
- 1996-09-18 US US08/715,431 patent/US5812543A/en not_active Expired - Fee Related
- 1996-09-19 KR KR1019960040967A patent/KR970019200A/en not_active Application Discontinuation
- 1996-09-20 CN CN96121122A patent/CN1094703C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1151671A (en) | 1997-06-11 |
| US5812543A (en) | 1998-09-22 |
| CN1094703C (en) | 2002-11-20 |
| JPH0993652A (en) | 1997-04-04 |
| KR970019200A (en) | 1997-04-30 |
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Legal Events
| Date | Code | Title | Description |
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| FZDE | Discontinued |
Effective date: 20050912 |
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| FZDE | Discontinued |
Effective date: 20050912 |