CA2570269A1 - Distributed resource reservation in a wireless adhoc network - Google Patents
Distributed resource reservation in a wireless adhoc network Download PDFInfo
- Publication number
- CA2570269A1 CA2570269A1 CA002570269A CA2570269A CA2570269A1 CA 2570269 A1 CA2570269 A1 CA 2570269A1 CA 002570269 A CA002570269 A CA 002570269A CA 2570269 A CA2570269 A CA 2570269A CA 2570269 A1 CA2570269 A1 CA 2570269A1
- Authority
- CA
- Canada
- Prior art keywords
- station
- mode
- common part
- format
- messages
- 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.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
- H04W84/10—Small scale networks; Flat hierarchical networks
- H04W84/12—WLAN [Wireless Local Area Networks]
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W8/00—Network data management
- H04W8/02—Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks
- H04W8/04—Registration at HLR or HSS [Home Subscriber Server]
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0012—Modulated-carrier systems arrangements for identifying the type of modulation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/14—Two-way operation using the same type of signal, i.e. duplex
- H04L5/1438—Negotiation of transmission parameters prior to communication
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
- H04L69/08—Protocols for interworking; Protocol conversion
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W28/00—Network traffic management; Network resource management
- H04W28/16—Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
- H04W28/26—Resource reservation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0023—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the signalling
- H04L1/0025—Transmission of mode-switching indication
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
- H04L69/22—Parsing or analysis of headers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W80/00—Wireless network protocols or protocol adaptations to wireless operation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks
Abstract
The invention relates to a method of communication in a wireless communication system comprising a first station and at least a second station wherein each of the station for at least a part of the time controls the communication within the system. The first station encodes and transmits messages having a first format in a first mode using at least one communication channel or having a second format in a second mode using one communication channel. The first and second formats have a common part. The second station receives and decodes at least the common part of messages transmitted either the first mode or the second mode. The common part comprises information on one or more upcoming transmissions of the first station.
Description
DISTRIBUTED RESOURCE RESERVATION IN A WIRELESS ADHOC NETWORK
The invention relates to a method of communication in a wireless communication system as defined in the preamble of claim 1.
The invention also relates to a wireless communication system and a wireless communication device.
Such a method of communication in a wireless communication system is disclosed in IEEE Std. 802.11a, 1999, Wireless LAN Medium Access Control (MAC) and Physical (PHY) specifications: High Speed Physical Layer in the 5 GHz Band, IEEE, NY, 1999. A wireless communication system conforming this standard operates in the 5 GHz license free ISM band and is able to support raw date rates ranging from 6 to 54 Mbit/sec using orthogonal frequency division multiplexing (OFDM). IEEE Std 802.1 lb discloses a similar communication system for operation in the 2.4 GHz ISM band. Within IEEE Std.
802.11 a and l lg channels having a bandwidth of 20 MHz are used to establish communication links. In general a channel in a wireless communication system is a sub-band for establishing a communication link within the frequency band in which the system operates. To satisfy the requirements of delay-bounded applications, a new specification has been proposed p802.1 l e incorporating data link layer functions to offer both statistic and parameterized QoS.
To support data rates up to about 100 Mbit/sec in the data link layer a new specification p802.1 ln will be proposed. In this proposal extensions to the l la-based PHY
and the l le-based MAC standards are introduced, while keeping a certain level of backward compatibility. The PHY extensions are based on the support of multiple antenna systems (MIMO) and transmission in 40 MHz bands, so-called dual channel operation.
Wireless local area networks (WLANs) such as wireless communication systems compliant with one of the versions of IEEE Std. 802.11 or its proposed extensions are organized in cells or so-called basic service sets (BSS). Such cells comprise a number of wireless stations. In a first mode of operation, the so-called infrastructure mode, one station within such a cell is arranged to provide communication with other cells, a master station or access point via an inter-cell system or distribution system. The additional stations are arranged to communicate with each other and stations in other cells via the access point.
The invention relates to a method of communication in a wireless communication system as defined in the preamble of claim 1.
The invention also relates to a wireless communication system and a wireless communication device.
Such a method of communication in a wireless communication system is disclosed in IEEE Std. 802.11a, 1999, Wireless LAN Medium Access Control (MAC) and Physical (PHY) specifications: High Speed Physical Layer in the 5 GHz Band, IEEE, NY, 1999. A wireless communication system conforming this standard operates in the 5 GHz license free ISM band and is able to support raw date rates ranging from 6 to 54 Mbit/sec using orthogonal frequency division multiplexing (OFDM). IEEE Std 802.1 lb discloses a similar communication system for operation in the 2.4 GHz ISM band. Within IEEE Std.
802.11 a and l lg channels having a bandwidth of 20 MHz are used to establish communication links. In general a channel in a wireless communication system is a sub-band for establishing a communication link within the frequency band in which the system operates. To satisfy the requirements of delay-bounded applications, a new specification has been proposed p802.1 l e incorporating data link layer functions to offer both statistic and parameterized QoS.
To support data rates up to about 100 Mbit/sec in the data link layer a new specification p802.1 ln will be proposed. In this proposal extensions to the l la-based PHY
and the l le-based MAC standards are introduced, while keeping a certain level of backward compatibility. The PHY extensions are based on the support of multiple antenna systems (MIMO) and transmission in 40 MHz bands, so-called dual channel operation.
Wireless local area networks (WLANs) such as wireless communication systems compliant with one of the versions of IEEE Std. 802.11 or its proposed extensions are organized in cells or so-called basic service sets (BSS). Such cells comprise a number of wireless stations. In a first mode of operation, the so-called infrastructure mode, one station within such a cell is arranged to provide communication with other cells, a master station or access point via an inter-cell system or distribution system. The additional stations are arranged to communicate with each other and stations in other cells via the access point.
Alternatively, in a second mode the so-called ad hoc mode a master station or access point is absent. A cell operating in the ad hoc mode is usually called an independent basic service set (IBSS). A cell operating in the ad hoc mode lacks the possibility to communicate with other cells, since the required infrastructure, basically an access point, is missing.
In a draft for the MAC specification of P802.1 ln an access mechanism is foreseen in which the master station reserves time slots on the medium for a station within the BSS. This access mechanism, called Reverse Direction Request (RDR) is an extended version of a mechanism known from IEEE Std. 802.11e and allows guaranteed (periodic) resource allocation (time slots and bandwidth) to a station. This supports transmission of real-time or otherwise time critical data.
However in an IBSS no master station is present that can grant access to guarantee a certain quality of service (QoS) for one or more stations. The stations have to access the medium in a more or less random access mode by using for instance the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol of IEEE Std.
802.11.
Even though extensions exist for the CSMA/CA protocol such as for instance the so-called EDCA (enhanced direkt carrier access) access mode in IEEE Std. 802.11 e for an improved quality of service no allocations can be guaranteed and no periodic access is possible. This may result in frequent collisions resulting in data loss and thus in an inefficient use of the medium. Furthennore, it is known that CSMA/CA protocol is less suitable for multi-hop communication, that is communication between stations, routed via other stations.
The W02004/114598 Al describes a method to reserve the medium for a further transmission. It describes a reservation mechanism where reservation information is included piggyback in MAC (Medium Access Control) headers of messages or in the payload of data messages or acknowledge messages. However it does not differentiate between mulitple antenna mode and single antenna mode.
Yet another method to reserve the medium for a further transmission is described in non published European patent application PCT/IB2005/051454. Here the stations distribute their reservation information in a dedicated beacon. In an infrastructure-based IEEE 802.11 network BSS beacons are normally sent by an Access Point. In an ad hoc IEEE 802.11 network beacons are sent alternately by different stations. In both cases per super frame only a single access point or station sends a beacon. However in the 802.11 standard, it is not explicitly excluded that several stations send their own beacon. In European patent application PCT/IB2005/051454 such a beacon is sent only for the purpose of distributing the reservation information. Other stations, which do not understand a distributed reservation protocol (DRP) but only the original IEEE Std. 802.11 stand, will interpret these beacons as coming from access points. The reservations are distributed in beacons, because stations not necessarily listen to data and acknowledgement packets or messages of other stations but they do listen to beacons transmitted by other stations. In order to assure that the reservations are respected by other stations, the other stations must be aware of the reservations of their neighboring stations. Furthermore, signaling a reservation in a beacon by means of legacy mechanisms, such as the so-called "contention-free period"
guarantees that reservations are respected by legacy stations, even if these do not understand a distributed reservation protocol. However it does alos not differentiate between mulitple antenna mode and single antenna mode.
Amongst others it is an object of the invention to provide a method to reduce access collisions by allowing a guaranteed access to the medium in the absence of a master station.
To this end the invention provides a method of communication in a wireless communication system comprising a first station and at least a second station wherein each of the station for at least a part of the time controls the communication within the system, wherein the first station encodes and transmits messages having a first format in a first mode using at least one communication channel or having a second format in a second mode using one communication channel, wherein the first and second formats have a common part, wherein the second station receives and decodes at least the common part of messages transmitted in either the first mode or the second mode, wherein the common part comprises information on one or more upcoming transmissions of the first station.
The method according to the invention solves the problem of access collisions in a wireless communication system operating in an ad hoc mode in which each of the stations controls the communication within the system for at least a part of the time by providing information on one or more upcoming transmissions in a message format that can be decoded by a station that can only decode information in one of the possible formats thereby increasing the "audience" for the message.
In a draft for the MAC specification of P802.1 ln an access mechanism is foreseen in which the master station reserves time slots on the medium for a station within the BSS. This access mechanism, called Reverse Direction Request (RDR) is an extended version of a mechanism known from IEEE Std. 802.11e and allows guaranteed (periodic) resource allocation (time slots and bandwidth) to a station. This supports transmission of real-time or otherwise time critical data.
However in an IBSS no master station is present that can grant access to guarantee a certain quality of service (QoS) for one or more stations. The stations have to access the medium in a more or less random access mode by using for instance the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol of IEEE Std.
802.11.
Even though extensions exist for the CSMA/CA protocol such as for instance the so-called EDCA (enhanced direkt carrier access) access mode in IEEE Std. 802.11 e for an improved quality of service no allocations can be guaranteed and no periodic access is possible. This may result in frequent collisions resulting in data loss and thus in an inefficient use of the medium. Furthennore, it is known that CSMA/CA protocol is less suitable for multi-hop communication, that is communication between stations, routed via other stations.
The W02004/114598 Al describes a method to reserve the medium for a further transmission. It describes a reservation mechanism where reservation information is included piggyback in MAC (Medium Access Control) headers of messages or in the payload of data messages or acknowledge messages. However it does not differentiate between mulitple antenna mode and single antenna mode.
Yet another method to reserve the medium for a further transmission is described in non published European patent application PCT/IB2005/051454. Here the stations distribute their reservation information in a dedicated beacon. In an infrastructure-based IEEE 802.11 network BSS beacons are normally sent by an Access Point. In an ad hoc IEEE 802.11 network beacons are sent alternately by different stations. In both cases per super frame only a single access point or station sends a beacon. However in the 802.11 standard, it is not explicitly excluded that several stations send their own beacon. In European patent application PCT/IB2005/051454 such a beacon is sent only for the purpose of distributing the reservation information. Other stations, which do not understand a distributed reservation protocol (DRP) but only the original IEEE Std. 802.11 stand, will interpret these beacons as coming from access points. The reservations are distributed in beacons, because stations not necessarily listen to data and acknowledgement packets or messages of other stations but they do listen to beacons transmitted by other stations. In order to assure that the reservations are respected by other stations, the other stations must be aware of the reservations of their neighboring stations. Furthermore, signaling a reservation in a beacon by means of legacy mechanisms, such as the so-called "contention-free period"
guarantees that reservations are respected by legacy stations, even if these do not understand a distributed reservation protocol. However it does alos not differentiate between mulitple antenna mode and single antenna mode.
Amongst others it is an object of the invention to provide a method to reduce access collisions by allowing a guaranteed access to the medium in the absence of a master station.
To this end the invention provides a method of communication in a wireless communication system comprising a first station and at least a second station wherein each of the station for at least a part of the time controls the communication within the system, wherein the first station encodes and transmits messages having a first format in a first mode using at least one communication channel or having a second format in a second mode using one communication channel, wherein the first and second formats have a common part, wherein the second station receives and decodes at least the common part of messages transmitted in either the first mode or the second mode, wherein the common part comprises information on one or more upcoming transmissions of the first station.
The method according to the invention solves the problem of access collisions in a wireless communication system operating in an ad hoc mode in which each of the stations controls the communication within the system for at least a part of the time by providing information on one or more upcoming transmissions in a message format that can be decoded by a station that can only decode information in one of the possible formats thereby increasing the "audience" for the message.
The inventions bases on the thought to transmit the reservation information within this part of the header which is not transmitted according to the mulitple antenna format. The header is used for train or calibrate the multiple antennas. A
first part of the header is transmitted in the single antenna format, wherein the second part is transmitted in the multiple antennna mode or multiple antennna format. By incorporating the reservation information into the first part header, which is also called common part, the reservation will recognized by the second stations which are not able to receive or to recognize the mulitple antenna format. The first stations are able to receive signals according to the mulitple antenna mode, wherein the second stations are eihter not trained to use the mulitple antenna mode or they are in principle not able to use the mulitple antenna mode. The invention is directed to infrastructure systems and ad hoc networks.
The above and other objects and features of the present invention will become more apparent from the following detailed description considered in connection with the accompanying drawings in which:
Fig. 1 shows a general overview of a communication system having an infrastructure according to one of the group of IEEE Std. 802.11 specifications;
Fig. 2 shows a general overview of an ad hoc communication system according to one of the group of IEEE Std. 802.11 specifications;
Fig. 3 shows an embodiment of the method according to the invention;
Fig. 4a, b and 5 show another embodiments of the method according to the invention.
In these figures identical parts are identified with identical references.
Fig. 1 shows a general overview of a communication system having an infrastructure according to one of the group of IEEE Std. 802.11 specifications. The basic element in the network architecture is called the basic service set (BSS). The BSS is defined as a group of stations (wireless nodes) which are located within a general limited physical area within which easch station (STA) is theoretically capable of communicating with every other STA (assuming an ideal environment with no communication barriers, physical or otherwise).
There are two basic wireless network design structures defined, ad hoc and infrastructure networks. An infrastructure-based IEEE 802.11 wireless network or 5 communication system is composed of one or more BSSs which are interconnected through another network such as an IEEE 802.3 wired Ethernet network. This connecting infrastructure is called the Distribution System (DS). With this infrastructure each BSS must have exactly one wireless station connected to the DS. This station provides the functionality to relay messages from the other STAs of the BSS to the DS. This STA is called the Access Point (AP) for its associated BSS. The entity comprised of the DS and its connected BSSs is called an Extended Service Set (ESS). For the purposes of IEEE 802.11, the fact that the DS
can move data between BSSs and to/from an external Portal is assumed, however the method used by the DS to accomplish this function is not defined.
A wireless communication with a proposed draft version of P802.1 ln has a similar set-up. The proposal foresees an access mechanism called HCCA (Hybrid Coordinator Controlled Access) in the access point or master station, in this case called the Hybrid Coordinator (HC), reserves time on the medium for a station. This access mechanism is taken from the IEEE Std. 802.11 e but has an added type of traffic specification called periodic RDR (Reverse Direction Request), which allow for periodic allocation of resources to a station. As a result, real-time and other time critical applications, which require periodic and/or guaranteed resource allocations, are well supported in an infrastructure mode of operation. However in this access mechanism no support is provided for a wireless coinmunication system operating in an ad hoc mode in which no access points are present.
Fig. 2 shows a general overview of an ad hoc communication system according to one of the groups of IEEE Std. 802.11 specifications. It comprises three stations STA1, STA2, and STA3. The BSS of an ad hoc network is referred to as an Independent BSS
(IBSS). An ad hoc wireless network is basically the opposite of an infrastructure-based wireless LAN (WLAN). An ad hoc WLAN has no infrastructure, and therefore no ability to communicate with external networks. An ad hoc WLAN is normally setup purely to permit multiple wireless stations to communicate with each other while requiring as little external hardware or management support as possible.
In known wireless communication systems operating in an ad hoc mode of communication, a so-called independent basic service set IBSS, periodic allocations and Quality of Service (QoS) guarantees are not provided, because no master station or access point is present that can grant periodic allocations. In the known systems stations have to access the medium in random access mode using a Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol. Even though IEEE 802.1 le provides some extensions of CSMA/CA for an improved quality of service support in its EDCA
access mode, no guarantees can be given and no periodic allocation is possible. As a result frequent collisions may occur that will hamper an efficient use of the medium.
Furthermore various simulation programs have shown the deficiencies of the CSMA/CA protocol for multi-hop communication.
The medium access method according to the invention solves the problem of access collisions and periodic reservations in an ad hoc mode of operation.
Owing to its distributed nature, the method according to the invention dos not require necessarily a central unit or master station for regulating communication with the system.
As discussed above in relation with Fig. 1 a proposed draft for IEEE 802.11n provides a so called Distributed Reservation Protocol. The proposal for P802.11n does not have such a reservation mechanism in the ad hoc mode of operation. A system compliant with the proposal for P802.11n will be a so-called Multiple Input Multiple Output (MIMO) system with various possible data rates. This means that a traffic stream is optimized for a specific receiver (or group of receivers) and other stations might not necessarily be able to overhear such a transmission. However, the distributed reservation protocol (DRP) requires the other stations to overhear the reservation announcements included in their neighbors' packets. The method according to the invention therefore foresees that the reservation information is included in that part of the Physical layer (PHY) header of the packets, which is transmitted at a robust low throughput data rate and eventually even single antenna transmission mode, which can be understood by most neighboring stations.
The DRP foresees that stations which are planning a data transmission, announce the starting point in time, duration of the transmission and eventually even the frequency or code channel in a reservation packet. This reservation packet is overheard by the other stations in the reception range of the sending station of the reservation request. The other stations store this information and defer from any medium access at the announced point in time on the respective frequency code channel and for the duration of the planned transmission. The reservation information can refer to a single reservation or a multitude of periodic reservations.
In a preferred embodiment of the DRP, the receiving station of a reservation request acknowledges the reservation request by returning a message repeating said reservation information, and other stations than the intended receiving station active in the reception range for transmissions of said receiving station perform the actions of storing said reservation information locally and defer from medium access during the time period and on the channel of the future transmission upon overhearing said acknowledgement message.
Thereby, in order to clear the medium also on the receiver side, the reservation packet is sent back by the intended receiving station, when it is received from the sending station. By these means, the other stations in the reception range of the intended receiving station are informed about the planned transmission of the sending station and can also defer from any medium access during the announced period. In a further preferred embodiment of the DRP, the reservation request (and response) include information on the priority or priority/traffic class of the transmission planned during the reserved period.
As mentioned above, DRP reservation information can be transmitted piggyback to DATA, ACK or other frames. Furthermore, it is necessary that neighboring stations overhear the reservation information to make a local entry and defer from medium access at the announced time period in the future. One problem is that in most current implementations a station will only decode the packet until the receiver address in the header of the frame. Only if the receiver address matches the own address or a multicast group, in which the station participates, the remainder of the frame will be decoded.
This suggests to transmit the reservation information before the receiver address or to add a rule that any packet has to be decoded up to the reservation information.
Stations decode the PHY header of most of the frames, because the PHY
header contains the DURATION of the frame exchange. This duration is used by the neighboring stations to set their so-called "Network Allocation Vector (NAV)", which controls their access to the medium. This suggests that the reservation information be included in a similar way in the PHY header than the DURATION field.
Finally the proposal for P802.11n relates to a MIMO system, in which neighboring stations might not be able to successfully decode packets that are transmitted in multiple transmit antennae mode (because the data stream is directed towards a specific receiver). In order to make the DRP protocol work, it is therefore required that the reservation information is included in a part of the frame that is transmitted on a single transmit antenna and at a low data rate. Note that the lower the data rate the further away the signal reaches, which is required for an effective protection of the future transmission from interfering transmissions. In the proposal for P802.11n there are two PHY
headers that are transmitted in addition to (and directly following) the legacy PHY header.
These HTSIG1 and HTSIG2 headers are transmitted at the robust BPSK modulation and on a single transmit antenna.
Fig. 3 shows an embodiment of the method according to the invention. In this embodiment the reservation information is included in the single antenna and/or robust modulation and coding PHY header of DATA and ACK frames. One of the two HT
headers can be used for transmit the reservation information as illustrated in Fig. 3.
The header as shown in fig. 3 includes a first part including the ST, LT, LEGA SF and the HT
filed. The second part comprises fields according to the multiple antenna format MIMO.
The first is used for transmitting the reservation information. In particular the reservation information is included into the HT field. However as shown ion the following figures 4a,b and 5. The only requirement according to the invention is to incorporate the reservation information into the first part of the header. The ST and The LT field are used for signalling the short training symbol and the long train symbol. The LEGA SF is used for signalling data to the legacy stations acocrding to Standards 802.11 a or 802.11 e etc. As shown the HT
field includes the reservation information for signalling of momentan and/or later reservation periods.
Fig. 4a, b and 5 show other embodiments of the method according to the invention. In this embodiment it is proposed to transmit the reservation information in a dedicated broadcast/multicast signalling packet, where the whole frame is transmitted by a single antenna and/or robust modulation and coding mode, as shown in Fig. 4a, b and Fig. 5.
In a third embodiment, the stations distribute their reservation information as part of a beacon frame, which is transmitted in a transmission mode that can be understood by all neighboring stations. The reservation can be signalled by announcing a contention-free period, which can be understood by legacy 802.11 stations.
The reservation information can e.g. consist of one or several of the following:
- period of the traffic - duration of the medium reservation - priority of data transmission - number of future reservation periods.
In another embodiment the starting point / period of the reservation is signalled relative to the beginning or end of the frame, in which the reservation information is included.
In a yet another embodiment the starting point / period of the reservation is signalled relative to the beginning of a superframe. The period of traffic field could e.g. be called "Target beacon Transmission Time Offset". In order to support periods of reservation that are bigger than the superframe duration, a field would have to be added in this second embodiment to signal that the reservation is included not in every but in every nt" superframe.
In order to signal periods of reservation that are smaller than a superframe duration, several reservation information elements would have to be included in the reserving frame.
The embodiments of the present invention described herein are intended to be taken in an illustrative and not a limiting sense. Various modifications may be made to these embodiments by those skilled in the art without departing from the scope of the present invention as defined in the appended claims.
It will be clear to a skilled person that the invention is not limited to usage in a wireless communication system but can also be applied in a wired communication system.
Furthermore, although the invention is discussed in relation to wireless communication systems compliant with IEEE Std 802.11 and/or extensions to this standard, it will be clear to a skilled person that the invention can be applied to other wireless communication systems too.
Also, although the discussed embodiments do not explicitly discuss this case, it will be clear to a skilled person that it is possible to make a repeated or periodic reservation by transmitting a single reservation message.
The invention also relates to any system that is using MIMO and dynamic data rate adaptation.
The invention may be applied advantageously in products complying with the upcoming standard IEEE 802.1 ln, either in chipsets as well as modules and consumer end products based on IEEE 802.11. IEEE 802.1 ln is the next generation of WLAN
with networking of consumer electronics apparatuses (e.g. audio en video equipment) as the main application. This is also the reason while the ad hoc mode of operation is very important, as not all homes will be equipped with an Access Points, but some consumer electronics devices might communicate directly with one another (in ad hoc mode).
first part of the header is transmitted in the single antenna format, wherein the second part is transmitted in the multiple antennna mode or multiple antennna format. By incorporating the reservation information into the first part header, which is also called common part, the reservation will recognized by the second stations which are not able to receive or to recognize the mulitple antenna format. The first stations are able to receive signals according to the mulitple antenna mode, wherein the second stations are eihter not trained to use the mulitple antenna mode or they are in principle not able to use the mulitple antenna mode. The invention is directed to infrastructure systems and ad hoc networks.
The above and other objects and features of the present invention will become more apparent from the following detailed description considered in connection with the accompanying drawings in which:
Fig. 1 shows a general overview of a communication system having an infrastructure according to one of the group of IEEE Std. 802.11 specifications;
Fig. 2 shows a general overview of an ad hoc communication system according to one of the group of IEEE Std. 802.11 specifications;
Fig. 3 shows an embodiment of the method according to the invention;
Fig. 4a, b and 5 show another embodiments of the method according to the invention.
In these figures identical parts are identified with identical references.
Fig. 1 shows a general overview of a communication system having an infrastructure according to one of the group of IEEE Std. 802.11 specifications. The basic element in the network architecture is called the basic service set (BSS). The BSS is defined as a group of stations (wireless nodes) which are located within a general limited physical area within which easch station (STA) is theoretically capable of communicating with every other STA (assuming an ideal environment with no communication barriers, physical or otherwise).
There are two basic wireless network design structures defined, ad hoc and infrastructure networks. An infrastructure-based IEEE 802.11 wireless network or 5 communication system is composed of one or more BSSs which are interconnected through another network such as an IEEE 802.3 wired Ethernet network. This connecting infrastructure is called the Distribution System (DS). With this infrastructure each BSS must have exactly one wireless station connected to the DS. This station provides the functionality to relay messages from the other STAs of the BSS to the DS. This STA is called the Access Point (AP) for its associated BSS. The entity comprised of the DS and its connected BSSs is called an Extended Service Set (ESS). For the purposes of IEEE 802.11, the fact that the DS
can move data between BSSs and to/from an external Portal is assumed, however the method used by the DS to accomplish this function is not defined.
A wireless communication with a proposed draft version of P802.1 ln has a similar set-up. The proposal foresees an access mechanism called HCCA (Hybrid Coordinator Controlled Access) in the access point or master station, in this case called the Hybrid Coordinator (HC), reserves time on the medium for a station. This access mechanism is taken from the IEEE Std. 802.11 e but has an added type of traffic specification called periodic RDR (Reverse Direction Request), which allow for periodic allocation of resources to a station. As a result, real-time and other time critical applications, which require periodic and/or guaranteed resource allocations, are well supported in an infrastructure mode of operation. However in this access mechanism no support is provided for a wireless coinmunication system operating in an ad hoc mode in which no access points are present.
Fig. 2 shows a general overview of an ad hoc communication system according to one of the groups of IEEE Std. 802.11 specifications. It comprises three stations STA1, STA2, and STA3. The BSS of an ad hoc network is referred to as an Independent BSS
(IBSS). An ad hoc wireless network is basically the opposite of an infrastructure-based wireless LAN (WLAN). An ad hoc WLAN has no infrastructure, and therefore no ability to communicate with external networks. An ad hoc WLAN is normally setup purely to permit multiple wireless stations to communicate with each other while requiring as little external hardware or management support as possible.
In known wireless communication systems operating in an ad hoc mode of communication, a so-called independent basic service set IBSS, periodic allocations and Quality of Service (QoS) guarantees are not provided, because no master station or access point is present that can grant periodic allocations. In the known systems stations have to access the medium in random access mode using a Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol. Even though IEEE 802.1 le provides some extensions of CSMA/CA for an improved quality of service support in its EDCA
access mode, no guarantees can be given and no periodic allocation is possible. As a result frequent collisions may occur that will hamper an efficient use of the medium.
Furthermore various simulation programs have shown the deficiencies of the CSMA/CA protocol for multi-hop communication.
The medium access method according to the invention solves the problem of access collisions and periodic reservations in an ad hoc mode of operation.
Owing to its distributed nature, the method according to the invention dos not require necessarily a central unit or master station for regulating communication with the system.
As discussed above in relation with Fig. 1 a proposed draft for IEEE 802.11n provides a so called Distributed Reservation Protocol. The proposal for P802.11n does not have such a reservation mechanism in the ad hoc mode of operation. A system compliant with the proposal for P802.11n will be a so-called Multiple Input Multiple Output (MIMO) system with various possible data rates. This means that a traffic stream is optimized for a specific receiver (or group of receivers) and other stations might not necessarily be able to overhear such a transmission. However, the distributed reservation protocol (DRP) requires the other stations to overhear the reservation announcements included in their neighbors' packets. The method according to the invention therefore foresees that the reservation information is included in that part of the Physical layer (PHY) header of the packets, which is transmitted at a robust low throughput data rate and eventually even single antenna transmission mode, which can be understood by most neighboring stations.
The DRP foresees that stations which are planning a data transmission, announce the starting point in time, duration of the transmission and eventually even the frequency or code channel in a reservation packet. This reservation packet is overheard by the other stations in the reception range of the sending station of the reservation request. The other stations store this information and defer from any medium access at the announced point in time on the respective frequency code channel and for the duration of the planned transmission. The reservation information can refer to a single reservation or a multitude of periodic reservations.
In a preferred embodiment of the DRP, the receiving station of a reservation request acknowledges the reservation request by returning a message repeating said reservation information, and other stations than the intended receiving station active in the reception range for transmissions of said receiving station perform the actions of storing said reservation information locally and defer from medium access during the time period and on the channel of the future transmission upon overhearing said acknowledgement message.
Thereby, in order to clear the medium also on the receiver side, the reservation packet is sent back by the intended receiving station, when it is received from the sending station. By these means, the other stations in the reception range of the intended receiving station are informed about the planned transmission of the sending station and can also defer from any medium access during the announced period. In a further preferred embodiment of the DRP, the reservation request (and response) include information on the priority or priority/traffic class of the transmission planned during the reserved period.
As mentioned above, DRP reservation information can be transmitted piggyback to DATA, ACK or other frames. Furthermore, it is necessary that neighboring stations overhear the reservation information to make a local entry and defer from medium access at the announced time period in the future. One problem is that in most current implementations a station will only decode the packet until the receiver address in the header of the frame. Only if the receiver address matches the own address or a multicast group, in which the station participates, the remainder of the frame will be decoded.
This suggests to transmit the reservation information before the receiver address or to add a rule that any packet has to be decoded up to the reservation information.
Stations decode the PHY header of most of the frames, because the PHY
header contains the DURATION of the frame exchange. This duration is used by the neighboring stations to set their so-called "Network Allocation Vector (NAV)", which controls their access to the medium. This suggests that the reservation information be included in a similar way in the PHY header than the DURATION field.
Finally the proposal for P802.11n relates to a MIMO system, in which neighboring stations might not be able to successfully decode packets that are transmitted in multiple transmit antennae mode (because the data stream is directed towards a specific receiver). In order to make the DRP protocol work, it is therefore required that the reservation information is included in a part of the frame that is transmitted on a single transmit antenna and at a low data rate. Note that the lower the data rate the further away the signal reaches, which is required for an effective protection of the future transmission from interfering transmissions. In the proposal for P802.11n there are two PHY
headers that are transmitted in addition to (and directly following) the legacy PHY header.
These HTSIG1 and HTSIG2 headers are transmitted at the robust BPSK modulation and on a single transmit antenna.
Fig. 3 shows an embodiment of the method according to the invention. In this embodiment the reservation information is included in the single antenna and/or robust modulation and coding PHY header of DATA and ACK frames. One of the two HT
headers can be used for transmit the reservation information as illustrated in Fig. 3.
The header as shown in fig. 3 includes a first part including the ST, LT, LEGA SF and the HT
filed. The second part comprises fields according to the multiple antenna format MIMO.
The first is used for transmitting the reservation information. In particular the reservation information is included into the HT field. However as shown ion the following figures 4a,b and 5. The only requirement according to the invention is to incorporate the reservation information into the first part of the header. The ST and The LT field are used for signalling the short training symbol and the long train symbol. The LEGA SF is used for signalling data to the legacy stations acocrding to Standards 802.11 a or 802.11 e etc. As shown the HT
field includes the reservation information for signalling of momentan and/or later reservation periods.
Fig. 4a, b and 5 show other embodiments of the method according to the invention. In this embodiment it is proposed to transmit the reservation information in a dedicated broadcast/multicast signalling packet, where the whole frame is transmitted by a single antenna and/or robust modulation and coding mode, as shown in Fig. 4a, b and Fig. 5.
In a third embodiment, the stations distribute their reservation information as part of a beacon frame, which is transmitted in a transmission mode that can be understood by all neighboring stations. The reservation can be signalled by announcing a contention-free period, which can be understood by legacy 802.11 stations.
The reservation information can e.g. consist of one or several of the following:
- period of the traffic - duration of the medium reservation - priority of data transmission - number of future reservation periods.
In another embodiment the starting point / period of the reservation is signalled relative to the beginning or end of the frame, in which the reservation information is included.
In a yet another embodiment the starting point / period of the reservation is signalled relative to the beginning of a superframe. The period of traffic field could e.g. be called "Target beacon Transmission Time Offset". In order to support periods of reservation that are bigger than the superframe duration, a field would have to be added in this second embodiment to signal that the reservation is included not in every but in every nt" superframe.
In order to signal periods of reservation that are smaller than a superframe duration, several reservation information elements would have to be included in the reserving frame.
The embodiments of the present invention described herein are intended to be taken in an illustrative and not a limiting sense. Various modifications may be made to these embodiments by those skilled in the art without departing from the scope of the present invention as defined in the appended claims.
It will be clear to a skilled person that the invention is not limited to usage in a wireless communication system but can also be applied in a wired communication system.
Furthermore, although the invention is discussed in relation to wireless communication systems compliant with IEEE Std 802.11 and/or extensions to this standard, it will be clear to a skilled person that the invention can be applied to other wireless communication systems too.
Also, although the discussed embodiments do not explicitly discuss this case, it will be clear to a skilled person that it is possible to make a repeated or periodic reservation by transmitting a single reservation message.
The invention also relates to any system that is using MIMO and dynamic data rate adaptation.
The invention may be applied advantageously in products complying with the upcoming standard IEEE 802.1 ln, either in chipsets as well as modules and consumer end products based on IEEE 802.11. IEEE 802.1 ln is the next generation of WLAN
with networking of consumer electronics apparatuses (e.g. audio en video equipment) as the main application. This is also the reason while the ad hoc mode of operation is very important, as not all homes will be equipped with an Access Points, but some consumer electronics devices might communicate directly with one another (in ad hoc mode).
Claims (8)
1. A method of communication in a wireless communication system comprising a first station and at least a second station wherein each of the station for at least a part of the time controls the communication within the system, wherein the first station encodes and transmits messages having a first format in a first mode using at least one communication channel or having a second format in a second mode using one communication channel, wherein the first and second formats have a common part, wherein the second station receives and decodes at least the common part of messages transmitted either the first mode or the second mode, wherein the common part comprises information on one or more upcoming transmissions of the first station.
2. A method as claimed in claim 1, characterized in that in the first mode messages are transmitted on at least one channel and in the second mode messages are transmitted on one channel.
3. A method as claimed in claim 1 or 2, characterized in that the information of the first station comprises a request to at least the second station to reserve time slots in at least one channel to allow undisturbed periodic transmissions of the first station
4. A method as claimed in any of the claims 1 to 3, characterized in that the common part comprises a first header and a second header, wherein the information on periodic transmissions is encoded in the first header or the second header.
5. A method as claimed in any of the claims 1 to 4, characterized in that messages in the first mode are compliant with one of the standards out of the group of IEEE
Std. 802.11 a, IEEE Std. 802.11b, IEEE Std. 802.11g, and IEEE Std. 802.11e.
Std. 802.11 a, IEEE Std. 802.11b, IEEE Std. 802.11g, and IEEE Std. 802.11e.
6. A wireless communication system comprising a first station and at least a second station wherein in use each of the station for at least a part of the time controls the communication within the system, wherein the first station is arranged for encoding and transmitting messages having a first format in a first mode or having a second format in a second mode, wherein the first and second formats have a common part, wherein the second station is arranged for receiving and decoding at least the common part of messages transmitted either the first mode or the second mode wherein the common part comprises information on periodic transmissions of the first station.
7. A wireless communication device for use as a first station in a wireless communication system comprising the first station and at least a second station wherein each of the station for at least a part of the time controls the communication within the system, wherein the first station is arranged for encoding and transmitting messages having a first format in a first mode or having a second format in a second mode, wherein the first and second formats have a common part, wherein the second station is arranged for receiving and decoding at least the common part of messages transmitted either the first mode or the second mode wherein the common part comprises information on periodic transmissions of the first station.
8. A wireless communication device for use as a second station in a wireless communication system comprising a first station and the second station wherein each of the station for at least a part of the time controls the communication within the system, wherein the first station is arranged for encoding and transmitting messages having a first format in a first mode or having a second format in a second mode, wherein the first and second formats have a common part, wherein the second station is arranged for receiving and decoding at least the common part of messages transmitted either the first mode or the second mode wherein the common part comprises information on periodic transmissions of the first station.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP04102754.1 | 2004-06-16 | ||
| EP04102754 | 2004-06-16 | ||
| PCT/IB2005/051927 WO2005125047A1 (en) | 2004-06-16 | 2005-06-10 | Distributed resource reservation in a wireless adhoc network |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2570269A1 true CA2570269A1 (en) | 2005-12-29 |
| CA2570269C CA2570269C (en) | 2013-08-20 |
Family
ID=34970072
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2570269A Active CA2570269C (en) | 2004-06-16 | 2005-06-10 | Distributed resource reservation in a wireless adhoc network |
Country Status (18)
| Country | Link |
|---|---|
| US (2) | US7953053B2 (en) |
| EP (1) | EP1762020B1 (en) |
| JP (1) | JP4679578B2 (en) |
| KR (1) | KR101170404B1 (en) |
| CN (1) | CN1969480B (en) |
| AR (1) | AR049919A1 (en) |
| AT (1) | ATE447267T1 (en) |
| BR (1) | BRPI0512066B1 (en) |
| CA (1) | CA2570269C (en) |
| DE (1) | DE602005017392D1 (en) |
| ES (1) | ES2334451T3 (en) |
| MX (1) | MXPA06014557A (en) |
| MY (1) | MY139940A (en) |
| RU (1) | RU2372721C2 (en) |
| TW (1) | TWI393384B (en) |
| UA (1) | UA91506C2 (en) |
| WO (1) | WO2005125047A1 (en) |
| ZA (1) | ZA200700431B (en) |
Families Citing this family (44)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050165946A1 (en) * | 2003-12-22 | 2005-07-28 | Intel Corporation | Bi-directional wireless LAN channel access |
| KR20070013864A (en) * | 2005-07-27 | 2007-01-31 | 삼성전자주식회사 | Device for channel time reservation conflict avoidance and resolution in wireless distributed mac systems, system comprising the device and method thereof |
| JP4715433B2 (en) * | 2005-10-03 | 2011-07-06 | ソニー株式会社 | Wireless communication system, wireless communication device, and computer program |
| KR100782844B1 (en) * | 2006-01-12 | 2007-12-06 | 삼성전자주식회사 | Method and apparatus for transmitting data frame using channel bonding in wireless LAN |
| US8275314B1 (en) | 2007-08-13 | 2012-09-25 | Marvell International Ltd. | Bluetooth scan modes |
| US8577305B1 (en) | 2007-09-21 | 2013-11-05 | Marvell International Ltd. | Circuits and methods for generating oscillating signals |
| US8625475B2 (en) | 2007-09-24 | 2014-01-07 | Qualcomm Incorporated | Responding to an interactive multicast message within a wireless communication system |
| US8457044B2 (en) * | 2007-09-24 | 2013-06-04 | Qualcomm Incorporated | Selective review of bundled messages from a wireless communication device |
| US9253742B1 (en) * | 2007-11-29 | 2016-02-02 | Qualcomm Incorporated | Fine timing for high throughput packets |
| US8588705B1 (en) | 2007-12-11 | 2013-11-19 | Marvell International Ltd. | System and method of determining Power over Ethernet impairment |
| KR101650109B1 (en) | 2008-06-16 | 2016-08-22 | 마벨 월드 트레이드 리미티드 | Short-range wireless communication |
| US8310967B1 (en) | 2008-06-19 | 2012-11-13 | Marvell International Ltd. | Infrastructure and ad-hoc node device |
| US8600324B1 (en) | 2008-06-27 | 2013-12-03 | Marvell International Ltd | Circuit and method for adjusting a digitally controlled oscillator |
| US9078270B2 (en) | 2008-07-03 | 2015-07-07 | Qualcomm Incorporated | Opportunistic relay scheduling in wireless communications |
| US8472968B1 (en) | 2008-08-11 | 2013-06-25 | Marvell International Ltd. | Location-based detection of interference in cellular communications systems |
| US9288764B1 (en) | 2008-12-31 | 2016-03-15 | Marvell International Ltd. | Discovery-phase power conservation |
| FR2942925A1 (en) * | 2009-03-03 | 2010-09-10 | Thomson Licensing | METHOD OF CALIBRATION OF MULTISECTORAL ANTENNA TERMINAL AND TERMINAL OF A MESH NETWORK |
| US8472427B1 (en) | 2009-04-06 | 2013-06-25 | Marvell International Ltd. | Packet exchange arbitration for coexisting radios |
| US8451761B2 (en) * | 2009-07-09 | 2013-05-28 | Lg Electronics Inc. | Power management method for station in wireless LAN system and station that supports same |
| US8599804B2 (en) * | 2009-08-07 | 2013-12-03 | Broadcom Corporation | Distributed signal field for communications within multiple user, multiple access, and/or MIMO wireless communications |
| US9066369B1 (en) | 2009-09-16 | 2015-06-23 | Marvell International Ltd. | Coexisting radio communication |
| FR2952463B1 (en) * | 2009-11-06 | 2012-12-21 | Somfy Sas | ORDERS COMMUNICATION IN A DOMOTIC NETWORK AND BETWEEN DOMOTIC NETWORKS. |
| US8340034B1 (en) | 2009-11-11 | 2012-12-25 | Marvell International Ltd. | Bluetooth and wireless LAN arbitration |
| US8717957B2 (en) * | 2010-02-10 | 2014-05-06 | Broadcom Corporation | Preamble and header bit allocation for power savings within multiple user, multiple access, and/or MIMO wireless communications |
| KR101755013B1 (en) * | 2010-03-11 | 2017-07-07 | 한국전자통신연구원 | Frame structure and communication method of coordinator, source station and relay station in a wireless network system |
| US8767771B1 (en) | 2010-05-11 | 2014-07-01 | Marvell International Ltd. | Wakeup beacons for mesh networks |
| WO2012054210A1 (en) | 2010-10-20 | 2012-04-26 | Marvell World Trade Ltd. | Pre-association discovery |
| US8750278B1 (en) | 2011-05-26 | 2014-06-10 | Marvell International Ltd. | Method and apparatus for off-channel device invitation |
| US9392469B2 (en) | 2011-06-03 | 2016-07-12 | Qualcomm Incorporated | Systems and methods for receiver based clear channel assessment |
| US8983557B1 (en) | 2011-06-30 | 2015-03-17 | Marvell International Ltd. | Reducing power consumption of a multi-antenna transceiver |
| US9125216B1 (en) | 2011-09-28 | 2015-09-01 | Marvell International Ltd. | Method and apparatus for avoiding interference among multiple radios |
| US9036517B2 (en) | 2012-01-09 | 2015-05-19 | Marvell World Trade Ltd. | Methods and apparatus for establishing a tunneled direct link setup (TDLS) session between devices in a wireless network |
| US9215708B2 (en) | 2012-02-07 | 2015-12-15 | Marvell World Trade Ltd. | Method and apparatus for multi-network communication |
| US9609676B1 (en) | 2012-03-30 | 2017-03-28 | Marvell International Ltd. | Efficient transition from discovery to link establishment |
| US9450649B2 (en) | 2012-07-02 | 2016-09-20 | Marvell World Trade Ltd. | Shaping near-field transmission signals |
| US20140064169A1 (en) * | 2012-09-05 | 2014-03-06 | Qualcomm Incorporated | Duty cycled transmissions |
| US9544782B2 (en) | 2012-11-02 | 2017-01-10 | Qualcomm Incorporated | Systems, apparatus, and methods for range extension of wireless communication |
| US9749371B2 (en) | 2012-12-27 | 2017-08-29 | Lg Electronics Inc. | Method and apparatus for multicasting/broadcasting in relay network of wireless LAN system |
| US9112790B2 (en) * | 2013-06-25 | 2015-08-18 | Google Inc. | Fabric network |
| CN107078790B (en) | 2014-09-19 | 2019-09-03 | 华为技术有限公司 | A kind of wireless local area network data transmission method and device |
| KR102253868B1 (en) * | 2014-12-12 | 2021-05-20 | 삼성전자주식회사 | Apparatus and method for operating ad hoc mode in wireless communication network |
| CN106255174B (en) * | 2016-07-25 | 2021-03-02 | 河南科技大学 | Method for direct communication between users in ultra-dense network |
| US10244536B1 (en) * | 2016-08-31 | 2019-03-26 | Marvell International Ltd. | Method and apparatus for determining whether a secondary channel is idle |
| CN109922502B (en) * | 2019-03-06 | 2021-07-27 | 清华大学 | Data transmission method and device for Ad hoc network communication |
Family Cites Families (35)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2298340B (en) * | 1994-12-22 | 1999-06-23 | Motorola Israel Ltd | Method of operating a communication system |
| US6084869A (en) * | 1997-10-06 | 2000-07-04 | Hughes Electronics Corporation | Resource reservation for packet-switched multiple-path communication system |
| US6788702B1 (en) * | 1999-10-15 | 2004-09-07 | Nokia Wireless Routers, Inc. | Protocol for neighborhood-established transmission scheduling |
| WO2001033770A2 (en) * | 1999-11-03 | 2001-05-10 | Itt Manufacturing Enterprises, Inc. | Methods and apparatus for coordinating channel access to shared parallel data channels |
| US6721331B1 (en) * | 1999-12-15 | 2004-04-13 | At&T Corp. | Method and apparatus for decentralized prioritized scheduling in a CSMA/CA wireless system |
| AU2002229157A1 (en) * | 2000-08-09 | 2002-02-18 | Hlan Inc. | Communications protocal for wireless lan harmonizing the ieee 802.11a and etsi hiperlan/2 standards |
| US6928061B1 (en) | 2000-09-06 | 2005-08-09 | Nokia, Inc. | Transmission-scheduling coordination among collocated internet radios |
| US6807165B2 (en) * | 2000-11-08 | 2004-10-19 | Meshnetworks, Inc. | Time division protocol for an ad-hoc, peer-to-peer radio network having coordinating channel access to shared parallel data channels with separate reservation channel |
| US7142527B2 (en) * | 2001-02-28 | 2006-11-28 | Nokia Inc. | System and method for transmission scheduling using network membership information and neighborhood information |
| US7042897B1 (en) * | 2001-04-05 | 2006-05-09 | Arcwave, Inc | Medium access control layer protocol in a distributed environment |
| EP1263168B1 (en) * | 2001-05-29 | 2006-06-28 | Kabushiki Kaisha Toshiba | Wireless communication apparatus |
| US6865176B2 (en) * | 2001-06-08 | 2005-03-08 | Motorola, Inc. | Method and apparatus for resolving half duplex message collisions |
| US7136361B2 (en) * | 2001-07-05 | 2006-11-14 | At&T Corp. | Hybrid coordination function (HCF) access through tiered contention and overlapped wireless cell mitigation |
| AU2002346389A1 (en) * | 2001-11-02 | 2003-05-12 | At And T Corp. | Wireless lans and neighborhood capture |
| US7245604B2 (en) * | 2001-11-02 | 2007-07-17 | At&T Corp. | Fixed deterministic post-backoff for cyclic prioritized multiple access (CPMA) contention-free sessions |
| US6869651B2 (en) * | 2001-12-19 | 2005-03-22 | Xerox Corporation | Substrate with raised surface portion |
| US6977944B2 (en) * | 2002-01-12 | 2005-12-20 | Conexant, Inc. | Transmission protection for communications networks having stations operating with different modulation formats |
| US7339897B2 (en) * | 2002-02-22 | 2008-03-04 | Telefonaktiebolaget Lm Ericsson (Publ) | Cross-layer integrated collision free path routing |
| US7184407B1 (en) * | 2002-05-10 | 2007-02-27 | Cisco Systems Wireless Networking (Australia) Pty Limited | Detecting, reporting and mitigating hidden nodes in a wireless data network |
| JP3968514B2 (en) * | 2002-07-05 | 2007-08-29 | ソニー株式会社 | Wireless communication system, wireless communication apparatus, wireless communication method, and computer program |
| US20040054798A1 (en) * | 2002-09-17 | 2004-03-18 | Frank Ed H. | Method and system for providing seamless connectivity and communication in a multi-band multi-protocol hybrid wired/wireless network |
| CN1417992A (en) * | 2002-11-27 | 2003-05-14 | 北京邮电大学 | Improved medium access contorl protocol of Ad-hoc network based on IEEE802.11 support |
| US7321762B2 (en) * | 2003-03-26 | 2008-01-22 | Conexant Systems, Inc. | Mechanism for reserving multiple channels of a single medium access control and physical layer |
| KR20040108474A (en) | 2003-06-17 | 2004-12-24 | 학교법인연세대학교 | DC Reactor with Bobbin equipped with Supplementary Winding |
| US10827524B2 (en) | 2003-06-25 | 2020-11-03 | Koninklijke Philips N.V. | Method of decentralized medium access control in a communications network |
| CN1207872C (en) * | 2003-07-22 | 2005-06-22 | 中国科学院计算技术研究所 | Method of ensuring track searching reliability in radio self organized network |
| US7373112B2 (en) * | 2003-08-08 | 2008-05-13 | Intel Corporation | Trained data transmission for communication systems |
| US8483105B2 (en) * | 2003-10-15 | 2013-07-09 | Qualcomm Incorporated | High speed media access control |
| US7410458B2 (en) | 2003-11-12 | 2008-08-12 | Isoray Medical, Inc. | Brachytherapy implant seeds |
| ES2698963T3 (en) * | 2004-01-08 | 2019-02-06 | Sony Corp | Wireless communication device and wireless communication procedure in a multi-format wireless LAN |
| US7680059B2 (en) * | 2004-02-13 | 2010-03-16 | Broadcom Corporation | Multiple protocol wireless communications in a WLAN |
| US7233773B2 (en) * | 2004-02-13 | 2007-06-19 | Broadcom Corporation | Configuring a MIMO communication |
| CN1951068B (en) | 2004-05-07 | 2012-12-05 | 皇家飞利浦电子股份有限公司 | A method of distributive reservation of a medium in a radio communications network |
| US7965691B2 (en) * | 2004-06-01 | 2011-06-21 | Broadcom Corporation | Network time reservation cancellation |
| US7486650B2 (en) * | 2004-09-27 | 2009-02-03 | Intel Corporation | Method, apparatus and system of wireless transmission |
-
2005
- 2005-06-10 EP EP05745544A patent/EP1762020B1/en active Active
- 2005-06-10 JP JP2007516118A patent/JP4679578B2/en active Active
- 2005-06-10 CN CN200580019769.7A patent/CN1969480B/en active Active
- 2005-06-10 UA UAA200613220A patent/UA91506C2/en unknown
- 2005-06-10 RU RU2007101374/09A patent/RU2372721C2/en active
- 2005-06-10 ES ES05745544T patent/ES2334451T3/en active Active
- 2005-06-10 MX MXPA06014557A patent/MXPA06014557A/en active IP Right Grant
- 2005-06-10 WO PCT/IB2005/051927 patent/WO2005125047A1/en active Application Filing
- 2005-06-10 CA CA2570269A patent/CA2570269C/en active Active
- 2005-06-10 KR KR1020077000856A patent/KR101170404B1/en active IP Right Grant
- 2005-06-10 AT AT05745544T patent/ATE447267T1/en not_active IP Right Cessation
- 2005-06-10 BR BRPI0512066A patent/BRPI0512066B1/en active IP Right Grant
- 2005-06-10 US US11/570,446 patent/US7953053B2/en active Active
- 2005-06-10 DE DE602005017392T patent/DE602005017392D1/en active Active
- 2005-06-13 TW TW094119539A patent/TWI393384B/en active
- 2005-06-14 MY MYPI20052698A patent/MY139940A/en unknown
- 2005-06-16 AR ARP050102464A patent/AR049919A1/en active IP Right Grant
-
2007
- 2007-01-15 ZA ZA200700431A patent/ZA200700431B/en unknown
-
2011
- 2011-04-19 US US13/089,443 patent/US8289942B2/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| RU2372721C2 (en) | 2009-11-10 |
| TWI393384B (en) | 2013-04-11 |
| ZA200700431B (en) | 2008-07-30 |
| US7953053B2 (en) | 2011-05-31 |
| CA2570269C (en) | 2013-08-20 |
| US8289942B2 (en) | 2012-10-16 |
| EP1762020B1 (en) | 2009-10-28 |
| US20110194519A1 (en) | 2011-08-11 |
| WO2005125047A8 (en) | 2007-02-15 |
| US20070248063A1 (en) | 2007-10-25 |
| ATE447267T1 (en) | 2009-11-15 |
| AR049919A1 (en) | 2006-09-13 |
| BRPI0512066A (en) | 2008-02-06 |
| DE602005017392D1 (en) | 2009-12-10 |
| UA91506C2 (en) | 2010-08-10 |
| KR20070039921A (en) | 2007-04-13 |
| CN1969480B (en) | 2014-09-17 |
| CN1969480A (en) | 2007-05-23 |
| MY139940A (en) | 2009-11-30 |
| JP2008503139A (en) | 2008-01-31 |
| JP4679578B2 (en) | 2011-04-27 |
| KR101170404B1 (en) | 2012-08-03 |
| TW200623728A (en) | 2006-07-01 |
| WO2005125047A1 (en) | 2005-12-29 |
| EP1762020A1 (en) | 2007-03-14 |
| BRPI0512066B1 (en) | 2018-11-27 |
| MXPA06014557A (en) | 2007-06-14 |
| RU2007101374A (en) | 2008-07-27 |
| ES2334451T3 (en) | 2010-03-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2570269C (en) | Distributed resource reservation in a wireless adhoc network | |
| US10447386B2 (en) | Method and system for controlling access to a wireless communication medium | |
| US7684428B2 (en) | System and method to free unused time-slots in a distributed MAC protocol | |
| US20060193279A1 (en) | Method and system for accessing a channel in a wireless communications network using multi-polling | |
| KR20200093470A (en) | Method and apparatus for multi-user communication in distributed wireless local access network | |
| JP2020535745A (en) | A method for transmitting and receiving ACK information in a wireless LAN system, and a device for this purpose. | |
| US20050169231A1 (en) | Method and system for detecting pending transmissions in a wireless data network | |
| US11122621B2 (en) | Method for transmitting and receiving data over secondary channel in wireless LAN system and apparatus therefor | |
| Cheng et al. | Adaptive channel switching for centralized MAC protocols in multihop wireless networks | |
| Wijaya | Interoperability concept for wireless lans | |
| KR200401646Y1 (en) | System for controlling access to a wireless communication medium | |
| KR20070022074A (en) | Wireless communication system, wireless communication device for use as a station in a wireless communication system, a method of communication within a wireless communication system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request |