CA2072972C - Method of controlling output power in a mobile radio communication system - Google Patents
Method of controlling output power in a mobile radio communication system Download PDFInfo
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- CA2072972C CA2072972C CA002072972A CA2072972A CA2072972C CA 2072972 C CA2072972 C CA 2072972C CA 002072972 A CA002072972 A CA 002072972A CA 2072972 A CA2072972 A CA 2072972A CA 2072972 C CA2072972 C CA 2072972C
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- distance
- transmitter
- output power
- receiver
- cell
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- 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
- H04W52/04—TPC
- H04W52/30—TPC using constraints in the total amount of available transmission power
- H04W52/36—TPC using constraints in the total amount of available transmission power with a discrete range or set of values, e.g. step size, ramping or offsets
- H04W52/367—Power values between minimum and maximum limits, e.g. dynamic range
-
- 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
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
Abstract
The invention relates to a method of controlling, in a cellular mobile radio communication system, the output power of radio signals transmitted from a transmitter to a receiver located in the same cell as the transmitter. The method is characterized by controlling the output power (P t) of the transmitter in dependence of a parameter, that is characteristic of the distance (D) between transmitter and receiver, to approximately follow, from a predetermined maximum output power (P max) that is transmitted when the distance between the transmitter and receiver is the maximum within the cell, a first function (a, b) that monotonically decreases with decreasing distance and approaches a predetermined minimum output power (P tmin) as the received power (P rmin), that is received when the distance between transmitter and receiver is the maximum within the cell, approximately follows a second function that monotonically increases with decreasing distance and approaches a maximum received power (P rmax) as the distance approaches zero.
Description
'v0 92/06544 A P?ETHOD OF CONTROLLING OUTPUT POWER IN A MOBILE RADIO COMMUNICATION SYSTEM
TECHNICAL FIELD
The present invention relates to a method for controlling, in a cellular mobile radio communication system, the output power of radio signals transmitted from a transmitter to a receiver that is located in the same cell as the transmitter. -PRIOR ART
A cellular mobile radio communication system comprises a number of cells, each containing a base station. These base stations communicate with mobile stations that can move freely within and between the cells. Since the number of available frequencies for the total system is limited, frequencies are reused for cells that are sufficiently separated from each other.
However, in such reuse of radio frequencies there is a risk that a radio connection is disturbed by signals intended for another radio connection using the same frequency. Thus, it is desirable to control the output power from for instance a mobile station in such a way that sufficient output power is transmitted to guarantee that the quality of the radio connection is maintained at the same time as the output power is limited not to unnecessa-rily disturb other radio connections that may use the same frequency.
In US Patent Specification 4 485 486 it has been suggested to control the output power of the mobile station in such a way that the signal received by the base station has constant power irrespective of the distance between mobile station and base station. A drawback of this previously known method is that ClI, that is the ratio between the power received at the base station of the carrier transmitted by the mobile station and the power of interfering signals, on the average is lower than is actually possible. This is due to the fact that the output power of the mobile station at small distances, where a further reduction of the output power from an already low level has a very small influence on the disturbance on other radio connections, is reduced to an extent uncalled for. On the other hand this further ~.mn~r~~a~~ v~r~ cv 20'72972 reduction can increase the risk of jeopardizing the mobile stations own radio connection.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method for controlling the output power from a mobile station and/or a base station in a cellular analog or digital mobile radio communica tion system in dependence of the distance between the base station and mobile station in such a way that the variation in transmitted power and received power is distributed in a more LO optimal way.
Accordingly the invention relates to a method of controlling, in a cellular mobile radio communication system, the output power of radio signals transmitted from a transmitter to a receiver, which is located in the same cell as the transmitter. This method is characterized by controlling the output power of the transmitter in dependence of a parameter, that is characteristic of the distance between transmitter and receiver, to approximately follow, from a predetermined maximum output power that is transmitted when the distance between the transmitter and receiver is the maximum within the cell, a first function that monotonically decreases with decreasing distance and approaches a predetermined minimum output power as the distance approaches zero, so that the power of the transmitted radio signals as received by the receiver from a minimum received power, that is received when the distance between transmitter and receiver is the maximum within the cell, approximately follows a second func-tion that monotonically increases with decreasing distance and approaches a maximum received power as the distance approaches zero.
The transmitter can comprise either a mobile station in the current cell or the base station of the same cell.
S(J~ST9'~'llTlE SHEET
'O 92/06544 3 PCf/S E91/00591 SHORT DESCRIPTION OF DRAWINGS
The invention, further objects and advantages obtained by the invention are best understood by reference to the following description and the accompanying drawings, in which:
Fig. 1 shows a cellular mobile telephone system;
Fig. 2 shows a number of cells in this cellular mobile telepho-ne system of which two use for instance the same radio frequency or radio channel;
Fig. 3 shows the output power Pt of the radio signal transmitted from a mobile station as a function of the distance D
between mobile station and base station in the method in accordance with the present~invention;
Fig. 4 shows the power PT of the radio signal received by the base station as a function of the distance D between mobile station and base station when the output power of the radio signal transmitted by the mobile station is controlled in accordance with the curve in fig. 3; and Fig. 5 illustrates a preferred embodiment of the method in accordance with the present invention.
PRE): ERRED EMBODIMENT
Figure 1 shows, as an example of a mobile radio communication system, the structure of an embodiment of a cellular mobile telephone system. Such a system comprises a number of cells, each cell in this embodiment including one base station BS. For reasons of simplicity only a number of such base stations BS are shown in the figure. Base stations BS are in radio contact with a number of mobile stations MS, of which only one is shown in the figure. Mobile station MS generally communicates with the base station BS of that cell in which it currently is located.
Figure 2 shows a number of cells in a cellular mobile telephone system. A mobile MSl is in radio contact with base station BSl in a first cell. In the second cell, separated from the first cell, there is another mobile MS2 in radio contact with base station BS2. If the load on the radio communication system is heavy and the distance between the first and the second cell is sufficient-ly large, both radio connections can use the same communication channel, for instance the same radio frequency or time slots for the same radio frequency. However, this implies that the output LO power transmitted from the base stations to the respective mobile stations should be sufficiently low to avoid interference between the cells. On the other hand the power can not be too low, since this would jeopardize the radio connection between the respective mobile and base station.
t5 Figures 3 and 4 show transmitted and received power, respec-tively, as functions of the distance D between mobile station and base station, on the one hand for the control method in accordan-ce with the above US Patent Specificaction ( dashed curves ) and on the other hand for the method in accordance with the present 20 invention (solid curves). In the following description it is assumed that P; (figure 3) is the power transmitted by the mobile station and that Pr (figure 4) is the power received by the base station. However, this assumption is made only to facilitate the description. P_ could instead represent the power transmitted by 25 the base station. Pr would then represent the power received by the mobile station.
As is apparent from the dashed curve in figure 4 the power PL
transmitted by the mobile station in accordance with the previously known method is controlled from the base station in 30 such a way that the power P~ received by the base station is maintained as constant as possible irrespective of where the mobile station is located within the current cell. Thus, P~ in this case essentially has no variation or the dynamic range zero.
Controlling in this way leads to that the power transmitted from 35 the mobile station (measured in dBm) from a minimum output power Po will vary linearly with the logarithm of the distance between mobile station and base station up to a maximum output power PimaX
5~~~~~~~~~ ~~E~
'O 92/06544 5 PCT/SE91/00591 at the outer regions of the cell, in accordance with the dashed curve in figure 3. Thus, PL in this case has the dynamic range Pcmax-' PO
At small distances between the mobile station and its own base station this control method, however, leads to a reduction in the power P~ transmitted by the mobile station even when the power level already is so low that the risk to disturb remote base stations is practically negligable. The reason for this is that the control method assumes that the received power Pr should be LO constant also in this region. Therefore the known method leads to a relatively large dynamic range of the transmitted signal, while the received signal is essentially constant.
The present invention is based on the insight that a better utilization of the radio connection can be obtained by dis-tributing the variation (dynamic range) between the transmitted signal and the received signal. An example of the control method in accordance with the invention is shown by the solid curves in figures 3 and 4. In accordance with the invention the transmitted power Pt is not controlled on the basis of a constant received power that is independent of the distance, rather the transmitted power P: is controlled to follow a function that monotonically decreases with the distance between mobile station and base station from a maximum value Ptmax. that is appropriate when the mobile station is located at the outer regions of the cell, and for instance asymptotically approaches a minimum value P:":~ as the distance approaches zero. The dynamic range for P; in this case is Only Pt,~ax-Ptmin~ Such a control method results in the solid curve in figure 4 for the received power Pr. It should be noted that the received signal power in this case steadily increases from a value Prmin to a value PL"ax as the distance between mobile station and base station decreases within the cell. The dynamic range for the received signal in this case is PLp,ax'Pr",in~ By this distribution of the variation in the radio connection such that both the transmitted and received signals have varying power within the cell, C/I of the connection is improved without increasing the risk of interference with other cells that use the same radio channel.
2fl'~2972 '~O 92/06544 6 PCT/SE91/00591 As an example of a suitable controlled curve the function:
Pt(D) = mill (P(D). Ptmex) can be mentioned, where the function P(D) is given by:
P(D) ' Ptmin + I0 lOg (DmP + DLL""~>P,D~P)I/P
In these formulas:
D designates the distance between mobile station and base station;
D, designates a characteristic distance that defines the location of the "knee" of the curve;
p designates a parameter that controls how smooth the transition between the flattened and steeper parts of the curve is (a large p results in a sharp transition);
n,m designate further parameters that control the shape of the curve.
Exemplifying values for the different parameters are:
D. - 2000 m p - 3 m - 0 n - 2.8 Ptmax - 38 dBm Ptmin - 28 dBm In practice the control method is not realized with a continuous function, but with stepped functions that approximate this conti-nuous function. A suitable number of levels for such stepped L5 functions has proven to be about ten levels. The value ef a stepped function for a given distance D can then easily be obtained from a table.
Sil~i~TB°E'L~'3'~' ~H~''~'_'1"
'fO 92/06544 7 PCT/SE91/00591 Figures 5a and 5b illustrate a preferred embodiment of the method in accordance with the present invention. The stepped functions a and b shown in figures 5a-b for sake of clearness comprise only a few levels. Figure 5a shows a step function a that approximates the solid control curve of figure 3 and that is appropriate when the mobile station leaves the base station. Correspondingly, figure 5b shows a stepped function b that approximates the solid control curve of figure 3 and that is appropriate when the mobile station approaches the base station. The stepped function a shown in 5a has been dashed in figure 5b. From figure 5b it is noted that the functions a and b have the same levels, but that the steps are mutually displaced along the distance axes. This results in a certain "hysteresis effect", which will be further described below when the control method in accordance with the preferred embodiment of the invention is described.
The control method is realized in the following way:
At each measurement instance the new measured distance is compared to the previous distance.
If the new distance is larger than the previous distance, an adjustment is to be performed in accordance with stepped function a and therefore the new desired value for the output power P; is retrieved from the corresponding table for function a.
If the new distance is smaller than the previous distance, an adjustment is to be performed in accordance with stepped function b and therefore the new desired value for the output power P_ is retrieved from the corresponding table for function b.
The result of this control method in accordance with the preferred embodiment is that if the mobile station happens to be near a step and alternately exceeds and underpasses, respec-tively, this step distance, a jumping desired value is avoided.
This is due to the fact that a~ transition from for instance a distance that is larger than the step distance to a distance that -WO 92/06544 g PCTlSE91/00591 is smaller than this distance also leads to a change of step function from a to b. However, the new step function b has a smaller step distance than the previous function. Therefore a larger distance reduction is required before the desired value is reduced. This feature can be considered as a sort of "hysteresis effect" .
The regulation described above is commanded by the base station, and the required calculations can be performed either in the base station or its control unit or even in the mobile services switching center to which the base station is connected.
In the above description the control method has been described as a function of the distance between mobile station and base station in the current cell. However, normally the exact distance is not known, which means that in practice a measure of or a parameter that depends on this distance is used. An example of such a measure is:
- The path loss between mobile station and base station. Since the base station over the control channel continuously commands the mobile station to transmit with a certain output power, this commanded output power can be compared to the actually received power. From this information the damping of the signal along the path between mobile station and base station can be calculated. This path loss is then an approxi-mate measure of the distance between the two stations.
- The time delay between mobile station and base station for transmitted and received radio signal. Since the mobile station transmits information at predetermined moments, which are controlled by the base station, the time delay between these moments and the actual moments of receipt can be used for calculating an approximate measure of the distance between mobile station and base station.
As has been mentioned above it is also possible to control the output power from the base station in accordance with the described principles. However, the control curve Pi does not have SU6iS?'~'~UTE SHEET
'~O 92/06544 9 PCT/SE91/00591 to be identical to the corresponding curve for a mobile station.
For instance the curve can have other maximum and minimum values and/or another "knee point". However the general shape of the curve is the same in both cases.
The man skilled in the art appreciates that different changes and modifications of the invention are possible without departure from the scope of the invention, which is defined by the attached patent claims.
TECHNICAL FIELD
The present invention relates to a method for controlling, in a cellular mobile radio communication system, the output power of radio signals transmitted from a transmitter to a receiver that is located in the same cell as the transmitter. -PRIOR ART
A cellular mobile radio communication system comprises a number of cells, each containing a base station. These base stations communicate with mobile stations that can move freely within and between the cells. Since the number of available frequencies for the total system is limited, frequencies are reused for cells that are sufficiently separated from each other.
However, in such reuse of radio frequencies there is a risk that a radio connection is disturbed by signals intended for another radio connection using the same frequency. Thus, it is desirable to control the output power from for instance a mobile station in such a way that sufficient output power is transmitted to guarantee that the quality of the radio connection is maintained at the same time as the output power is limited not to unnecessa-rily disturb other radio connections that may use the same frequency.
In US Patent Specification 4 485 486 it has been suggested to control the output power of the mobile station in such a way that the signal received by the base station has constant power irrespective of the distance between mobile station and base station. A drawback of this previously known method is that ClI, that is the ratio between the power received at the base station of the carrier transmitted by the mobile station and the power of interfering signals, on the average is lower than is actually possible. This is due to the fact that the output power of the mobile station at small distances, where a further reduction of the output power from an already low level has a very small influence on the disturbance on other radio connections, is reduced to an extent uncalled for. On the other hand this further ~.mn~r~~a~~ v~r~ cv 20'72972 reduction can increase the risk of jeopardizing the mobile stations own radio connection.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method for controlling the output power from a mobile station and/or a base station in a cellular analog or digital mobile radio communica tion system in dependence of the distance between the base station and mobile station in such a way that the variation in transmitted power and received power is distributed in a more LO optimal way.
Accordingly the invention relates to a method of controlling, in a cellular mobile radio communication system, the output power of radio signals transmitted from a transmitter to a receiver, which is located in the same cell as the transmitter. This method is characterized by controlling the output power of the transmitter in dependence of a parameter, that is characteristic of the distance between transmitter and receiver, to approximately follow, from a predetermined maximum output power that is transmitted when the distance between the transmitter and receiver is the maximum within the cell, a first function that monotonically decreases with decreasing distance and approaches a predetermined minimum output power as the distance approaches zero, so that the power of the transmitted radio signals as received by the receiver from a minimum received power, that is received when the distance between transmitter and receiver is the maximum within the cell, approximately follows a second func-tion that monotonically increases with decreasing distance and approaches a maximum received power as the distance approaches zero.
The transmitter can comprise either a mobile station in the current cell or the base station of the same cell.
S(J~ST9'~'llTlE SHEET
'O 92/06544 3 PCf/S E91/00591 SHORT DESCRIPTION OF DRAWINGS
The invention, further objects and advantages obtained by the invention are best understood by reference to the following description and the accompanying drawings, in which:
Fig. 1 shows a cellular mobile telephone system;
Fig. 2 shows a number of cells in this cellular mobile telepho-ne system of which two use for instance the same radio frequency or radio channel;
Fig. 3 shows the output power Pt of the radio signal transmitted from a mobile station as a function of the distance D
between mobile station and base station in the method in accordance with the present~invention;
Fig. 4 shows the power PT of the radio signal received by the base station as a function of the distance D between mobile station and base station when the output power of the radio signal transmitted by the mobile station is controlled in accordance with the curve in fig. 3; and Fig. 5 illustrates a preferred embodiment of the method in accordance with the present invention.
PRE): ERRED EMBODIMENT
Figure 1 shows, as an example of a mobile radio communication system, the structure of an embodiment of a cellular mobile telephone system. Such a system comprises a number of cells, each cell in this embodiment including one base station BS. For reasons of simplicity only a number of such base stations BS are shown in the figure. Base stations BS are in radio contact with a number of mobile stations MS, of which only one is shown in the figure. Mobile station MS generally communicates with the base station BS of that cell in which it currently is located.
Figure 2 shows a number of cells in a cellular mobile telephone system. A mobile MSl is in radio contact with base station BSl in a first cell. In the second cell, separated from the first cell, there is another mobile MS2 in radio contact with base station BS2. If the load on the radio communication system is heavy and the distance between the first and the second cell is sufficient-ly large, both radio connections can use the same communication channel, for instance the same radio frequency or time slots for the same radio frequency. However, this implies that the output LO power transmitted from the base stations to the respective mobile stations should be sufficiently low to avoid interference between the cells. On the other hand the power can not be too low, since this would jeopardize the radio connection between the respective mobile and base station.
t5 Figures 3 and 4 show transmitted and received power, respec-tively, as functions of the distance D between mobile station and base station, on the one hand for the control method in accordan-ce with the above US Patent Specificaction ( dashed curves ) and on the other hand for the method in accordance with the present 20 invention (solid curves). In the following description it is assumed that P; (figure 3) is the power transmitted by the mobile station and that Pr (figure 4) is the power received by the base station. However, this assumption is made only to facilitate the description. P_ could instead represent the power transmitted by 25 the base station. Pr would then represent the power received by the mobile station.
As is apparent from the dashed curve in figure 4 the power PL
transmitted by the mobile station in accordance with the previously known method is controlled from the base station in 30 such a way that the power P~ received by the base station is maintained as constant as possible irrespective of where the mobile station is located within the current cell. Thus, P~ in this case essentially has no variation or the dynamic range zero.
Controlling in this way leads to that the power transmitted from 35 the mobile station (measured in dBm) from a minimum output power Po will vary linearly with the logarithm of the distance between mobile station and base station up to a maximum output power PimaX
5~~~~~~~~~ ~~E~
'O 92/06544 5 PCT/SE91/00591 at the outer regions of the cell, in accordance with the dashed curve in figure 3. Thus, PL in this case has the dynamic range Pcmax-' PO
At small distances between the mobile station and its own base station this control method, however, leads to a reduction in the power P~ transmitted by the mobile station even when the power level already is so low that the risk to disturb remote base stations is practically negligable. The reason for this is that the control method assumes that the received power Pr should be LO constant also in this region. Therefore the known method leads to a relatively large dynamic range of the transmitted signal, while the received signal is essentially constant.
The present invention is based on the insight that a better utilization of the radio connection can be obtained by dis-tributing the variation (dynamic range) between the transmitted signal and the received signal. An example of the control method in accordance with the invention is shown by the solid curves in figures 3 and 4. In accordance with the invention the transmitted power Pt is not controlled on the basis of a constant received power that is independent of the distance, rather the transmitted power P: is controlled to follow a function that monotonically decreases with the distance between mobile station and base station from a maximum value Ptmax. that is appropriate when the mobile station is located at the outer regions of the cell, and for instance asymptotically approaches a minimum value P:":~ as the distance approaches zero. The dynamic range for P; in this case is Only Pt,~ax-Ptmin~ Such a control method results in the solid curve in figure 4 for the received power Pr. It should be noted that the received signal power in this case steadily increases from a value Prmin to a value PL"ax as the distance between mobile station and base station decreases within the cell. The dynamic range for the received signal in this case is PLp,ax'Pr",in~ By this distribution of the variation in the radio connection such that both the transmitted and received signals have varying power within the cell, C/I of the connection is improved without increasing the risk of interference with other cells that use the same radio channel.
2fl'~2972 '~O 92/06544 6 PCT/SE91/00591 As an example of a suitable controlled curve the function:
Pt(D) = mill (P(D). Ptmex) can be mentioned, where the function P(D) is given by:
P(D) ' Ptmin + I0 lOg (DmP + DLL""~>P,D~P)I/P
In these formulas:
D designates the distance between mobile station and base station;
D, designates a characteristic distance that defines the location of the "knee" of the curve;
p designates a parameter that controls how smooth the transition between the flattened and steeper parts of the curve is (a large p results in a sharp transition);
n,m designate further parameters that control the shape of the curve.
Exemplifying values for the different parameters are:
D. - 2000 m p - 3 m - 0 n - 2.8 Ptmax - 38 dBm Ptmin - 28 dBm In practice the control method is not realized with a continuous function, but with stepped functions that approximate this conti-nuous function. A suitable number of levels for such stepped L5 functions has proven to be about ten levels. The value ef a stepped function for a given distance D can then easily be obtained from a table.
Sil~i~TB°E'L~'3'~' ~H~''~'_'1"
'fO 92/06544 7 PCT/SE91/00591 Figures 5a and 5b illustrate a preferred embodiment of the method in accordance with the present invention. The stepped functions a and b shown in figures 5a-b for sake of clearness comprise only a few levels. Figure 5a shows a step function a that approximates the solid control curve of figure 3 and that is appropriate when the mobile station leaves the base station. Correspondingly, figure 5b shows a stepped function b that approximates the solid control curve of figure 3 and that is appropriate when the mobile station approaches the base station. The stepped function a shown in 5a has been dashed in figure 5b. From figure 5b it is noted that the functions a and b have the same levels, but that the steps are mutually displaced along the distance axes. This results in a certain "hysteresis effect", which will be further described below when the control method in accordance with the preferred embodiment of the invention is described.
The control method is realized in the following way:
At each measurement instance the new measured distance is compared to the previous distance.
If the new distance is larger than the previous distance, an adjustment is to be performed in accordance with stepped function a and therefore the new desired value for the output power P; is retrieved from the corresponding table for function a.
If the new distance is smaller than the previous distance, an adjustment is to be performed in accordance with stepped function b and therefore the new desired value for the output power P_ is retrieved from the corresponding table for function b.
The result of this control method in accordance with the preferred embodiment is that if the mobile station happens to be near a step and alternately exceeds and underpasses, respec-tively, this step distance, a jumping desired value is avoided.
This is due to the fact that a~ transition from for instance a distance that is larger than the step distance to a distance that -WO 92/06544 g PCTlSE91/00591 is smaller than this distance also leads to a change of step function from a to b. However, the new step function b has a smaller step distance than the previous function. Therefore a larger distance reduction is required before the desired value is reduced. This feature can be considered as a sort of "hysteresis effect" .
The regulation described above is commanded by the base station, and the required calculations can be performed either in the base station or its control unit or even in the mobile services switching center to which the base station is connected.
In the above description the control method has been described as a function of the distance between mobile station and base station in the current cell. However, normally the exact distance is not known, which means that in practice a measure of or a parameter that depends on this distance is used. An example of such a measure is:
- The path loss between mobile station and base station. Since the base station over the control channel continuously commands the mobile station to transmit with a certain output power, this commanded output power can be compared to the actually received power. From this information the damping of the signal along the path between mobile station and base station can be calculated. This path loss is then an approxi-mate measure of the distance between the two stations.
- The time delay between mobile station and base station for transmitted and received radio signal. Since the mobile station transmits information at predetermined moments, which are controlled by the base station, the time delay between these moments and the actual moments of receipt can be used for calculating an approximate measure of the distance between mobile station and base station.
As has been mentioned above it is also possible to control the output power from the base station in accordance with the described principles. However, the control curve Pi does not have SU6iS?'~'~UTE SHEET
'~O 92/06544 9 PCT/SE91/00591 to be identical to the corresponding curve for a mobile station.
For instance the curve can have other maximum and minimum values and/or another "knee point". However the general shape of the curve is the same in both cases.
The man skilled in the art appreciates that different changes and modifications of the invention are possible without departure from the scope of the invention, which is defined by the attached patent claims.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOW:
1. A method of controlling, in a cellular mobile radio communication system, the output power of radio signals transmitted from a transmitter to a receiver, which is located in the same cell as the transmitter, characterized by controlling the output power of the transmitter in dependence of a parameter, that is characteristic of the distance between transmitter and receiver, to approximately follow, from a predetermined maximum output power (P tmax) that is transmitted when the distance between the transmitter and receiver is the maximum within the cell, a first function that monotonically decreases with decreasing distance and approaches a predetermined minimum output power (P tmin) as the distance approaches zero, so that the power (P r) of the transmitted radio signals as received by the receiver from a minimum received power (P min), that is received when the distance between transmitter and receiver is maximum within the cell, approximately follows a second function that monotonically increases with decreasing distance and approaches a maximum received power (P rmax) as the distance approaches zero.
2. The method in accordance with claim 1, characterized by controlling the output power of radio signals transmitted from a mobile station (MS) in a cell to a base station (BS) of the same cell.
3. The method of claim 1, characterized by controlling the output power of radio signals transmitted from the base station (BS) in a cell to a mobile station (MS) in the same cell .
4. The method of claim 2 or 3, characterized by commanding the regulation from the base station (BS) of the cell.
5. The method of any of the preceding claims, characterized by approximating the monotonically decreasing first function with two stepped functions (a, b), each with a predetermined number of discrete levels, of which the first (a) is appropriate for increasing distances and the second is appropriate for decreasing distances.
6. The method of claim 5, characterized by both stepped functions (a, b) having the same levels but having the transitions from one level to the next located at different distances, depending on whether the mobile station moves towards or away from the base station.
7. The method of claim 5 or 6, characterized by said stepped functions having ten discrete levels.
8. The method of any of the preceding claims, characterized by said parameter characteristic of the distance comprises the path loss between transmitter and receiver.
9. The method of any of the preceding claims 1-7, characterized by said parameter characteristic of the distance comprises the time delay between transmitter and receiver for transmitted and received radio signal.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9003196A SE467386B (en) | 1990-10-05 | 1990-10-05 | PROCEDURE CONTROLS OUTPUTS IN MOBILE RADIO SYSTEM |
| SE9003196-4 | 1990-10-05 | ||
| PCT/SE1991/000591 WO1992006544A1 (en) | 1990-10-05 | 1991-09-09 | A method of controlling output power in a mobile radio communication system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2072972A1 CA2072972A1 (en) | 1992-04-06 |
| CA2072972C true CA2072972C (en) | 2001-02-20 |
Family
ID=20380578
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002072972A Expired - Lifetime CA2072972C (en) | 1990-10-05 | 1991-09-09 | Method of controlling output power in a mobile radio communication system |
Country Status (15)
| Country | Link |
|---|---|
| US (1) | US5390338A (en) |
| EP (1) | EP0479745B1 (en) |
| JP (1) | JP3002535B2 (en) |
| AT (1) | ATE127975T1 (en) |
| AU (1) | AU640535B2 (en) |
| CA (1) | CA2072972C (en) |
| DE (1) | DE69112974T2 (en) |
| DK (1) | DK0479745T3 (en) |
| ES (1) | ES2077212T3 (en) |
| FI (1) | FI102576B1 (en) |
| HK (1) | HK1007848A1 (en) |
| MX (1) | MX9101305A (en) |
| NO (1) | NO179655C (en) |
| SE (1) | SE467386B (en) |
| WO (1) | WO1992006544A1 (en) |
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| US6137840A (en) * | 1995-03-31 | 2000-10-24 | Qualcomm Incorporated | Method and apparatus for performing fast power control in a mobile communication system |
| US5761622A (en) * | 1995-05-18 | 1998-06-02 | Ericsson Inc. | Method and apparatus for controlling operation of a portable or mobile battery-operated radios |
| SE9600502L (en) * | 1996-02-12 | 1997-08-13 | Telia Ab | Method for evaluation of antenna tilt |
| US5815532A (en) * | 1996-05-01 | 1998-09-29 | Glenayre Electronics, Inc. | Method and apparatus for peak-to-average ratio control in an amplitude modulation paging transmitter |
| FI104025B (en) | 1996-08-28 | 1999-10-29 | Nokia Telecommunications Oy | Power control method and cellular radio system |
| US5893035A (en) * | 1996-09-16 | 1999-04-06 | Qualcomm Incorporated | Centralized forward link power control |
| US6151502A (en) * | 1997-01-29 | 2000-11-21 | Qualcomm Incorporated | Method and apparatus for performing soft hand-off in a wireless communication system |
| USRE39177E1 (en) * | 1997-01-29 | 2006-07-11 | Qualcomm, Inc. | Method and apparatus for performing soft hand-off in a wireless communication system |
| US5893036A (en) * | 1997-01-30 | 1999-04-06 | Motorola, Inc. | Transmission power control method |
| US5933781A (en) * | 1997-01-31 | 1999-08-03 | Qualcomm Incorporated | Pilot based, reversed channel power control |
| US5987326A (en) * | 1997-02-11 | 1999-11-16 | Qualcomm Incorporated | Transmit power reduction for a high speed CDMA link in soft handoff |
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| US6396867B1 (en) * | 1997-04-25 | 2002-05-28 | Qualcomm Incorporated | Method and apparatus for forward link power control |
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| US5982760A (en) * | 1997-06-20 | 1999-11-09 | Qualcomm Inc. | Method and apparatus for power adaptation control in closed-loop communications |
| US6426960B2 (en) | 1997-06-24 | 2002-07-30 | Qualcomm Incorporated | Increased capacity data transmission in a CDMA wireless communication system |
| US6055428A (en) * | 1997-07-21 | 2000-04-25 | Qualcomm Incorporated | Method and apparatus for performing soft hand-off in a wireless communication system |
| US6188678B1 (en) * | 1997-08-07 | 2001-02-13 | Qualcomm Inc. | Method and apparatus for adaptive closed loop power control using open loop measurements |
| US6147981A (en) * | 1997-08-07 | 2000-11-14 | Qualcomm Incorporated | Method and apparatus for predictive parameter control with loop delay |
| US6070085A (en) | 1997-08-12 | 2000-05-30 | Qualcomm Inc. | Method and apparatus for controlling transmit power thresholds based on classification of wireless communication subscribers |
| US6097972A (en) * | 1997-08-29 | 2000-08-01 | Qualcomm Incorporated | Method and apparatus for processing power control signals in CDMA mobile telephone system |
| US6343213B1 (en) * | 1997-10-24 | 2002-01-29 | Nortel Networks Limited | Method to protect against interference from mobile radios |
| KR100285310B1 (en) * | 1998-07-29 | 2001-04-02 | 윤종용 | Method for controlling forward power control parameter using erasure indicator bit in cdma communication system |
| US6690938B1 (en) | 1999-05-06 | 2004-02-10 | Qualcomm Incorporated | System and method for reducing dropped calls in a wireless communications network |
| US6643517B1 (en) | 1999-10-15 | 2003-11-04 | Nortel Networks Limited | Method of using location information for interference protection |
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| JP3991543B2 (en) | 2000-01-11 | 2007-10-17 | 株式会社日立製作所 | Imaging device |
| JP3848068B2 (en) * | 2000-09-12 | 2006-11-22 | 株式会社エヌ・ティ・ティ・ドコモ | CDMA radio transmission apparatus, CDMA radio transmission / reception system, transmission power control method for CDMA radio transmission apparatus, and transmission power control method for radio transmission apparatus in CDMA radio transmission / reception system |
| US8199696B2 (en) * | 2001-03-29 | 2012-06-12 | Qualcomm Incorporated | Method and apparatus for power control in a wireless communication system |
| JP2006025028A (en) * | 2004-07-06 | 2006-01-26 | Nissan Motor Co Ltd | Inter vehicle communication device |
| CN102075267A (en) * | 2010-12-30 | 2011-05-25 | 青海西部矿业科技有限公司 | Differential game-based cognitive radio (CR) system power control method |
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| FR2068850A5 (en) * | 1969-10-03 | 1971-09-03 | Cit Alcatel | |
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| US5204970A (en) * | 1991-01-31 | 1993-04-20 | Motorola, Inc. | Communication system capable of adjusting transmit power of a subscriber unit |
-
1990
- 1990-10-05 SE SE9003196A patent/SE467386B/en not_active IP Right Cessation
-
1991
- 1991-09-09 WO PCT/SE1991/000591 patent/WO1992006544A1/en active IP Right Grant
- 1991-09-09 AU AU87214/91A patent/AU640535B2/en not_active Ceased
- 1991-09-09 ES ES91850219T patent/ES2077212T3/en not_active Expired - Lifetime
- 1991-09-09 CA CA002072972A patent/CA2072972C/en not_active Expired - Lifetime
- 1991-09-09 EP EP91850219A patent/EP0479745B1/en not_active Expired - Lifetime
- 1991-09-09 DK DK91850219.6T patent/DK0479745T3/en active
- 1991-09-09 JP JP3516561A patent/JP3002535B2/en not_active Expired - Lifetime
- 1991-09-09 DE DE69112974T patent/DE69112974T2/en not_active Expired - Lifetime
- 1991-09-09 AT AT91850219T patent/ATE127975T1/en active
- 1991-09-27 MX MX9101305A patent/MX9101305A/en not_active IP Right Cessation
-
1992
- 1992-05-20 FI FI922290A patent/FI102576B1/en active
- 1992-06-04 NO NO922207A patent/NO179655C/en not_active IP Right Cessation
-
1994
- 1994-04-11 US US08/225,940 patent/US5390338A/en not_active Expired - Lifetime
-
1998
- 1998-06-26 HK HK98107054A patent/HK1007848A1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| JP3002535B2 (en) | 2000-01-24 |
| NO179655B (en) | 1996-08-12 |
| EP0479745B1 (en) | 1995-09-13 |
| SE9003196L (en) | 1992-04-06 |
| EP0479745A1 (en) | 1992-04-08 |
| MX9101305A (en) | 1992-06-05 |
| FI102576B (en) | 1998-12-31 |
| JPH05502991A (en) | 1993-05-20 |
| ES2077212T3 (en) | 1995-11-16 |
| DK0479745T3 (en) | 1995-11-13 |
| FI102576B1 (en) | 1998-12-31 |
| NO179655C (en) | 1996-11-20 |
| SE9003196D0 (en) | 1990-10-05 |
| US5390338A (en) | 1995-02-14 |
| FI922290A0 (en) | 1992-05-20 |
| ATE127975T1 (en) | 1995-09-15 |
| NO922207L (en) | 1992-06-04 |
| AU640535B2 (en) | 1993-08-26 |
| HK1007848A1 (en) | 1999-04-23 |
| SE467386B (en) | 1992-07-06 |
| WO1992006544A1 (en) | 1992-04-16 |
| NO922207D0 (en) | 1992-06-04 |
| DE69112974T2 (en) | 1996-03-14 |
| DE69112974D1 (en) | 1995-10-19 |
| AU8721491A (en) | 1992-04-28 |
| FI922290A (en) | 1992-05-20 |
| CA2072972A1 (en) | 1992-04-06 |
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