JP2001217774A - Total transmission power control method for base station in cdma mobile communication system and base station apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively control total transmission power without generating a call loss in another call when assigning prescribed transmission power to a novel call or a call of a power increase request. SOLUTION: A distance measuring part 218 measures the distance to an object mobile station on the basis of the propagation time of a leading wave in a finger circuit 212. On the basis of the measured distance, a distance comparing part 224 detects whether this mobile station is approaching to a present station. Corresponding to the distance of the mobile station, a maximum transmission power determining part 226 determines the optimal maximum transmission power. In the case of determination, an excessive power operating part 230 finds excessive transmission power from the average value of present transmission power and the maximum transmission power. Information representing such call states is recorded, through a transmitting/receiving managing part 236, on a call state storage part 242 of a call control block 202. When the assignment of the transmission power is newly generated, a call managing part 240 accesses the call state storage part 242 and a total transmission power managing part 244. When the total transmission power is insufficient, the excessive transmission power to the approaching mobile station or mobile station within a fixed distance is reduced and that transmission power is newly assigned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CDMA (Code Divis).
The present invention relates to a total transmission power control method and a base station apparatus for a base station in a mobile communication system of an ion multiple access type, and more particularly, to a total transmission power control method in a CDMA mobile communication system suitable for use, for example, in a high traffic base station. And a base station apparatus.

[0002]

2. Description of the Related Art As is well known, in a cellular type CDMA mobile communication system, each base station controls transmission power to a mobile station in order to obtain uniform communication quality within a service area. ing. For example, the base station of each cell transmits a desired signal reception power to an interference wave reception power ratio (hereinafter referred to as SIR (Signal to Interfere
nce power ratio) is controlled based on the transmission power to each mobile station. That is, when the measured SIR is smaller than the reference value, the mobile station transmits a request signal to increase the transmission power to the base station. It was measured
If the SIR is larger than the reference value, a request signal to reduce the transmission power is transmitted to the base station. Thereby, when the base station receives the request signal, the base station increases or decreases the transmission power to the mobile station at every predetermined control step according to the request signal.

[0003] In this case, when the total value of the transmission power to each mobile station in the base station, that is, the total transmission power increases and approaches a predetermined maximum transmission power, the mobile station increases the transmission power. Even when a request signal to be transmitted to the base station is transmitted, the base station may not be able to increase the transmission power as desired by the mobile station because the total transmission power exceeds the maximum transmission power. Was.

Conventionally, as a total transmission power control method and a base station apparatus corresponding to the shortage of the total transmission power of the base station as described above, for example, one disclosed in Japanese Patent Application Laid-Open No. H11-74834 has been proposed. This base station apparatus includes a total transmission power calculation unit that calculates the total transmission power P _total by summing the transmission power to each mobile station, and a comparator that compares the result with a predetermined maximum total transmission power P _max when a reduction rate calculating unit and the result obtain the predetermined power reduction rate D _t based on the comparison result from the total transmission power and comparator from the total transmission power calculator when exceeds the maximum total transmit power, using power reduction rate D _t by the calculated result was achieved, and a transmission power determining unit for determining a transmission power to each mobile station.

[0005] In such a configuration, the total transmission power control method uses a desired transmission power of a transmission power control target channel i, which is one communication channel selected to control transmission power from a plurality of communication channels. Calculate P _a (i). The resulting desired transmission power P _a (i) and the transmission power P _tx (j) currently set for each communication channel j, which is a communication channel other than the transmission power control target channel, are calculated by the total transmission power calculator. And the total transmit power of the base station
P _total is required. The calculated _total transmission power P _total is compared with a maximum total transmission power P _max set in advance by a comparator.

[0006] Power at its result, if the total transmission power P _total is greater than predefined by that the maximum total transmit power P _max which was required, reduction rate calculator unit based on the comparison result and the total transmit power P _total The reduction rate _Dt is obtained, and the calculation result is supplied to the transmission power determination unit. Thus, in the transmission power determining unit sets the value of reduced desired transmission power P _a (i) using a power reduction rate D _t as a new transmission power of the transmission power control object channel i, further each current communication Channel j
The transmission power P _tx (j) set for the respective communication channels j is reduced by using the power reduction rate D _t.
Is set as a new transmission power. As a result, the transmission power to each mobile station is controlled so that the total transmission power P _total of the base station does not exceed a predetermined maximum total transmission power P _max .

[0007]

However, in the above-mentioned conventional technology, the communication channel i to be controlled is a channel under communication, and for example, the total transmission power is insufficient for a request to increase the transmission power. Power reduction rate D _t
The seeking, corresponding in the case since reduced to uniformly transmit power of each communication channel at its power reduction rate D _t, which is new to the call in a state where the total transmission power of the base station is insufficient occurs There was a problem that it could not be done. For example, if the transmission power of a communication channel is barely maintaining the quality, a predetermined transmission power is allocated to a new call, and the transmission power of another communication channel is reduced. However, there is a problem that a call loss occurs in the channel during the communication.

[0008] The present invention solves the above-mentioned problems, and when the total transmission power is insufficient, the transmission power can be effectively increased for a new call or a power increase request without causing a call loss in a channel under communication. It is an object of the present invention to provide a total transmission power control method and a base station apparatus in a CDMA mobile communication system to which the base station apparatus can be assigned.

[0009]

In order to solve the above problems, a total transmission power control method according to the present invention sets a radio link between a plurality of mobile stations by code division multiple access and reduces the transmission power. In the total transmission power control method of the base station in the CDMA mobile communication system that performs communication while controlling, the distance from the own station to the mobile station is measured at a predetermined cycle based on the propagation time of the received wave from the mobile station. A first step of detecting whether or not the mobile station is approaching its own station based on the measurement result to determine the direction of movement, and a movement corresponding to the distance based on the measurement result of the first step. A second step of obtaining an appropriate maximum transmission power to the station, obtaining an average value of transmission power to the mobile station at the present time, and obtaining surplus transmission power from the average value and the maximum transmission power; Or increase transmission power When the transmission power has to be newly allocated by the request, the excess transmission power obtained in the second step is reduced from the transmission power to the mobile station approaching the own station detected in the first step, And allocating the surplus transmission power to the new request.

In this case, in the third step, when the total transmission power is further insufficient, the transmission power to the mobile station whose distance from the mobile station detected in the first step is constant is determined. It is preferable to include a fourth step of reducing the surplus transmission power obtained in the second step.

[0011] Further, when the total transmission power is insufficient, a call during soft handoff and a call other than the soft handoff are distinguished, and the transmission power is controlled by one of the mobile stations during soft handoff. A fifth step of detecting whether the mobile station is a mobile station, and, based on the detection result of the fifth step, reducing the transmission power to the mobile station in the soft hand whose transmission power is not controlled by the own station. Advantageously, a sixth step is included.

In this case, the fifth step is a step of detecting whether the mobile station is moving away from its own station and detecting whether the transmission power to the mobile station is smaller than a predetermined value. And a step of measuring the reception level from the mobile station to detect whether the desired signal reception power to interference wave reception power ratio satisfies a predetermined level, and, as a result of those steps, A mobile station during soft handoff in which the transmission power is smaller than a predetermined value even though the mobile station is moving away from the own station, and the ratio of desired wave reception power to interference wave reception power does not satisfy a predetermined level. And reducing the transmission power to the mobile station.

The sixth step is a step of detecting whether or not the mobile station is approaching the mobile station after setting the power reduction of the call during the soft handoff, and as a result, moving away from the mobile station. Monitoring the mobile station until it is handed off to another base station, and canceling the reduction of transmission power to the mobile station when approaching the own station and returning to normal transmission power control when approaching the own station. And may be included.

Further, the second step includes a step of obtaining a maximum transmission power to the mobile station with respect to the distance from the own station in advance, and creating a maximum transmission power table representing the relationship; And updating the maximum transmission power table based on the relationship between the result of the above and the call blocking rate.

On the other hand, a base station apparatus according to the present invention comprises a plurality of radio channel control blocks for controlling a radio link established with a mobile station by code division multiple access, and assigns a call to each of these radio channel control blocks to each other. In a CDMA mobile communication system including a call control block for controlling a call, a radio channel control block determines a distance between the mobile station and the mobile station based on a propagation time of a wave received from the mobile station. Distance measuring means for measuring at a predetermined period, whether or not the mobile station is approaching its own station based on the measurement result of the distance measuring means, a moving direction detecting means for detecting the moving direction, and a distance measuring means Maximum transmission power determining means for determining the maximum transmission power to the mobile station based on the measurement result, and determine the average value of the transmission power to the mobile station at the current time,
A surplus power calculation means for obtaining surplus power based on the average value and the maximum transmission power from the maximum transmission power determination means, wherein the call control block newly increases transmission power by a new call or a request to increase transmission power. If it is necessary to perform the call management, the surplus power calculated by the surplus power calculating means is reduced from the transmission power to the mobile station approaching the own station detected by the moving direction detecting means, and the new request is allocated to a new request. It is characterized by including means.

In this case, when the total transmission power is further insufficient, the call management means calculates the surplus from the transmission power to the mobile station whose distance from the mobile station detected by the moving direction detection means is constant. It is preferable to reduce the surplus power obtained by the power calculation means.

Further, the call management means distinguishes between the call during the soft handoff and the other call and determines whether the call during the soft handoff is a mobile station whose transmission power is controlled by its own station. Including, when the total transmission power is insufficient, reducing the transmission power to the mobile station during soft handoff that the own station does not control the transmission power from the determination result of the determination means , To a new request.

Further, the base station apparatus according to the present invention includes a maximum transmission power table for determining the maximum transmission power to the mobile station corresponding to the distance from the own station to the mobile station and a maximum transmission power table for the total transmission power control. And a table updating means for updating based on the relationship between the result of the above and the call blocking rate.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a base station total transmission power control method and a base station apparatus in a CDMA mobile communication system according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a base station apparatus to which the total transmission power control method according to the present invention is applied. The base station apparatus according to the present embodiment sets a radio link between a plurality of mobile stations by code division multiple access and performs communication.
MA (Code Division Multiple Access) is a fixed wireless device applied to the mobile communication system, for example,
As shown in FIG. 2, a base station controller connected to a fixed network
Under the control of ten, each predetermined service area SA, S
B, ..., a plurality of mobile stations moving or passing through 12, 14,
, Are radio transmission / reception devices used as cellular base stations 20, 22,... For making and receiving calls via radio lines, respectively.

In particular, in this embodiment, for example, in a high traffic base station, it is determined whether a mobile station in communication is approaching, moving away, or stopping at its own station. Detected based on time, for example, when a new call occurs, reduce the surplus transmission power to the mobile station approaching the own station or the surplus transmission power of the mobile station at a certain distance from the own station, The main feature is that the reduced transmission power is allocated to a new call to effectively control the total transmission power.

Specifically, the base station apparatus according to the present embodiment
As shown in FIG. 1, a plurality of radio channel control blocks 200, 2
, And a call control block 202. The radio channel control block 200 is a radio transmission / reception circuit for controlling a communication channel to each mobile station. The correlator 210 receives a received wave from the mobile station received by a common antenna (not shown). The received wave is a broadband communication wave including a spread spectrum wave from a plurality of mobile stations and a multipath signal wave due to fading or the like.

The correlator 210 is a signal separation circuit for separating a desired desired signal from the received signal, and obtains a correlation between the received signal and a spreading code assigned to the desired signal to obtain a spread spectrum signal. This is a secondary demodulation circuit for despreading the modulated signal. The desired wave signal separated by the correlator 210 is assigned to each of the finger (Finger 1 to N) circuits 212, 212,... According to the power threshold for each communication path.

The finger circuit 212 is a primary demodulation circuit that reproduces an original carrier from a desired wave signal in which intersymbol interference or the like has occurred due to fading or the like and obtains a baseband signal.
A detection circuit is provided for performing chip synchronization holding of signals of respective communication paths and detecting a reception correlation power value and a reception timing of the assigned communication path. Finger circuit
The demodulated signal from 212 is supplied to a RAKE receiving section 214. Further, the detected reception correlation power value is supplied to a reception level measurement section 216, and the reception timing signal is supplied to a distance measurement section 218, respectively.

The rake receiving section 214 is a decoding circuit for decoding the demodulated signal from the finger circuit 212 through a channel through rate decoding and error correction. In this embodiment, the rake receiving section 214 combines outputs from the respective finger circuits 212. The channel is decoded from the obtained received data to decode the original data. The decoded received data includes a transmission power control bit (TPC) for requesting the base station to increase or decrease the transmission power to the base station.
Bit) is included. The TPC bit detection section 220 is a detection circuit that detects a TPC bit from the decoded data from the rake reception section 214. The detected TPC bit is supplied to the transmission power determination section 232.

On the other hand, the reception level measuring section 216 receives the ratio of the desired power of the received wave from the mobile station to the interference power (S) based on the received correlation power value detected by the finger circuit 212.
This is a measurement circuit that measures IR (Signal to Interference Ratio), and the measurement result is used as a transmission power control bit for requesting the mobile station to increase or decrease the transmission power. The measurement result is sequentially supplied to the transmission power determination unit 232 and the transmission / reception management unit 236.

On the other hand, the distance measuring section 218 periodically acquires the average value of the reception propagation time of the most advanced wave from the plurality of communication paths assigned to the finger circuit 212 by the correlator 210, and moves from its own station. In this embodiment, the measurement circuit measures the distance to the station. In the present embodiment, the most advanced wave is obtained from the difference between the reception timing of the communication path notified from the finger circuit 212 and the frame head detection position at the time of zero offset of the predetermined reference timing. And the distance to the mobile station is measured. The distance information measured by the distance measurement unit 218 is supplied to and stored in the distance storage unit 222, and is arbitrarily read by the distance comparison unit 224 and the maximum transmission power determination unit 226, respectively.

The distance comparing section 224 is a moving direction detecting circuit for detecting the moving direction of the mobile station from the history of the distance of the mobile station stored in the distance storage section 222. In this embodiment, the distance is measured at a predetermined cycle. The received distances are sequentially compared, and the increase / decrease of the distance is notified to the call control block 202 via the transmission / reception management unit 236.

The maximum transmission power determining unit 226 includes the distance storing unit 22
2 is a circuit that determines the optimum maximum transmission power to the mobile station based on the distance of the mobile station stored in 2.In this embodiment, the relationship between the distance from the own station and the maximum transmission power is determined in advance. The maximum transmission power is determined according to the maximum transmission power table 228 set. For example, as shown in FIG. 3, the maximum transmission power table 228 includes distances x ₁ , x ₂ ,
In each range of x ₃ , x ₄ (m), the optimal maximum transmission power Y _{1 to} Y ₅ (dBm) is obtained in advance, for example,
As shown in FIG. 4, the range x of the distance and the maximum transmission power
Y and a transmission power level L corresponding to them are stored. The determined maximum transmission power value is supplied to the call control block 202 via the transmission / reception management unit 236, and is supplied to the transmission power determination unit 232 via the surplus power calculation unit 230.

The surplus power calculation unit 230 is a calculation circuit for obtaining a surplus power that can be reduced from the transmission power to the mobile station.
In the present embodiment, the current transmission power is sequentially obtained from the transmission power determination unit 232, the average value is obtained, and the average value is obtained from the difference between the average value and the maximum transmission power value determined by the maximum transmission power determination unit 226. Find surplus power. The calculation result is supplied to the call control block 202 via the transmission / reception management unit 236.

The transmission power determining section 232 is provided with a surplus power calculating section 23.
0 is a power control circuit that increases or decreases the transmission power according to the TPC bit from the TPC bit detection unit 220 within the range of the maximum transmission power allocated from the maximum transmission power determination unit 226, and determines the transmission power. In this embodiment, at the time of power reduction, the call control block
Surplus power calculation unit based on the control signal supplied from 202
Reduce the surplus power determined in 230. The control signal for controlling the determined transmission power is sequentially supplied to the transmission section 234.

The transmission section 234 is a transmission circuit that generates a transmission wave to the mobile station under the power control of the transmission power determination section 232, and transmits transmission data from a partner station supplied via a base station controller. It includes an encoding circuit for encoding, a primary modulation circuit for modulating the encoded signal by a predetermined modulation method, and a secondary modulation circuit for further spectrum-spreading the modulated signal by a predetermined spreading code. In particular, the transmission power to the mobile station is controlled by controlling the carrier power and the spreading code power in the primary modulation. The generated transmission wave is combined with the transmission wave of another channel and transmitted from the antenna to the service area.

On the other hand, the transmission / reception management unit 236 is an information transmission circuit for exchanging information necessary for transmission / reception management with the call control block 202, in particular, information on transmission power control. Memory information from 222, distance comparison unit
The movement direction information from 224, the SIR value indicating the reception state from the reception level measurement unit 216, the surplus power value from the surplus power calculation unit 230 and the maximum transmission power value are supplied to the call control block 202, respectively. The control signal for power reduction from the call control block 202 is supplied to the transmission power determination unit 232.

The call control block 202 is a general control circuit that allocates a call to each of the radio channel control blocks 200, 200,... Under the control of the base station control device, and executes the general call control. In this embodiment, as shown in FIG. 1, a call management unit 240, a call state storage unit 242, and a total transmission power management unit 244 are included. The call management section 240 is a control circuit that manages call information from the base station control device to the mobile station and call information from the mobile station, and executes overall call management of each radio line control block 200. In the present embodiment, a control signal for instructing transmission power control including assignment of the maximum transmission power for each call is generated. The call information indicating the management state is written to and read from the call state storage unit 242.

The call state storage unit 242 is a storage circuit for storing respective information indicating the call state managed by the call management unit 240. For example, in this embodiment, the transmission / reception management unit of each radio line control block 200 The transmission power to the mobile station notified via 236, the SIR value indicating the reception level from the mobile station, the distance to the mobile station, and the call management information such as the direction of movement are sequentially stored.

The total transmission power management unit 244 is a power management unit that manages transmission power that can be assigned to each radio channel control block 200, that is, the total transmission power of the entire base station. The management unit 240 manages the maximum transmission power of each call and the total value of those transmission powers, the reduced power level of the maximum transmission power of each call, and the total value of the reduced power levels.

Next, a total transmission power control method of the base station in the CDMA mobile communication system according to the present embodiment will be described with reference to flowcharts shown in FIGS.
The operation will be described together with the operation. In the operation state after power-on and initial setting (sub-step SS10), the base station apparatus
In 200, when a call is established and communication is started (substep SS12), as shown in FIG. 5, distance measurement is first performed (subroutine SUB1). The maximum transmission power level value is determined using the obtained distance to the mobile station (subroutine SUB2). In this way, a call is performed while performing control according to the communication conditions set between the mobile station and the base station 200. In step S14, it is determined whether the call has ended. If the call is still ongoing (NO), the process returns to the subroutine SUB1 to repeat the distance measurement with the mobile station. If the call has ended (YES), step S16
Proceed to. When the operation of the base station apparatus 200 is continued (N
O), proceed to step S12 and wait until the next call is generated. When stopping operation of base station apparatus 200 (YES
), The power is turned off, and the process ends.

Next, the operation of each subroutine will be described. In the subroutine SUB1 for performing distance measurement, first, in a sub-substep SS10, the distance measurement unit 218 determines the average value of the reception propagation time of the most advanced wave from among the plurality of communication paths allocated to the finger circuit 212 by the correlator 210. Are acquired at regular intervals (see FIG. 6). Next, the distance measuring unit 218 calculates the distance from the own station to the mobile station based on the acquired reception propagation time of the most advanced wave, and stores the calculated distance in the distance storage unit 222.
Are sequentially written (sub-substep SS12).

Next, proceeding to sub-sub-step SS14, the distance comparing section 224 compares the current distance stored in the distance storage section 222 with the previously stored distance, and calculates the distance based on the result. Determine whether there has been an increase or decrease. The result is temporarily stored in the distance storage unit 222. Next, proceeding to sub-substep SS16, distance comparing section 224
Based on the comparison result of SS14, it is determined whether the increase or decrease of the distance is monotonous.

If it is determined that the distance has not monotonically increased or decreased (NO), the history indicating the distance comparison result is deleted from the distance storage unit 222 in sub-step SS18, and the sub-step SS18 is executed. Return to SS10 and start comparison measurement of distance from the beginning. If it is determined in sub-step SS16 that the distance monotonously increases or decreases (YES), the sub-step SS20
Then, it is determined whether or not the increase or decrease of the distance is monotonous continuously for a specified number of times or more. If the increase or decrease of the distance is less than the specified number of times (NO), the process returns to sub-step SS10 and returns to sub-step SS10.
Repeat the steps up to SS20 to continue measuring the distance.
If the distance monotonously increases or decreases in sub-step SS16 and the increase or decrease continues for a specified number of times in sub-step SS20 (YES), the process proceeds to sub-step SS22 to temporarily stop the distance measurement. .

Next, proceeding to sub-step SS24, the distance comparing section 224 determines whether or not the distance is monotonically increasing. If it is determined that the increase is monotonous (YES), information indicating that the mobile station is away from the own station is generated, and the result is notified to the call management unit 240 via the transmission / reception management unit 236 ( Sub-step SS26). If not monotonically increasing (NO), it is determined whether the distance is monotonically decreasing (sub-step SS28). When it is determined that it is monotonically decreasing (YES)
Then, information indicating that the mobile station is approaching its own station is generated, and the result is notified to the call management unit 240 via the transmission / reception management unit 236 (substep SS30). On the other hand, when it is not determined that the distance is monotonically decreasing (NO), it is determined that there is no change in the increase or decrease of the distance, no information on the moving direction is generated, and the mobile station stops in sub-step SS30. Is considered to be When the information about the moving direction of the mobile station is notified to the call management unit 240 by each process (sub-steps SS26, SS30, SS32), the distance measurement ends and the process returns to return. Note that the distance comparison unit 224 may repeat the above steps again to always determine the moving direction of the mobile station.

The information indicating the moving direction of each mobile station sequentially detected in this way together with the distance information from the distance storage section 222 and the call management section 240 of the call control block 202 are stored.
, And the information is written into the call state storage unit 242.

Next, a processing routine for determining the transmission power level value to be transmitted to the mobile station will be described (subroutine SUB2). As shown in FIG. 7, in the maximum transmission power determination unit 226, first, in sub-step SS200, the distance storage unit
When the distance information is obtained from 222, the maximum transmission power table
228, the optimal maximum transmit power P _max for that mobile station
Ask for. Next, the maximum transmission power determination unit 226 proceeds to sub-step _SS202, and determines whether the obtained maximum transmission power P _max is larger than the currently allocated maximum transmission power value P _{c_max} . As a result, if the obtained maximum transmission power P _max is larger than the assigned maximum transmission power value P _{c_max} (NO), a request to increase the maximum transmission power is transmitted via the transmission / reception management unit 236 in sub-step SS204. To the call management unit 240. As a result, the call management unit 240 determines whether to increase the maximum transmission power value _{Pmax in} a subroutine SUB3 (total transmission power control processing) described later.

If the determined maximum transmission power P _max is smaller than the currently allocated maximum transmission power value P _{c_max} in the sub-step _SS202 (YES), the determined maximum transmission power P _max is used as a surplus power calculation unit. Supply 230. This is for confirming whether there is enough room when reducing the assignment of the maximum transmission power. Accordingly, the surplus power calculation unit 230 proceeds to sub-step SS206, acquires the transmission power value from the transmission power determination unit 232, and obtains the average value _Pavr of the current transmission power.

Next, in sub-step SS208, surplus power calculating section 230 _{determines that} the difference (P _max −P _avr ) between maximum transmission power P _max and average value P _avr of transmission power up to the present is equal to or greater than a specified value. It is determined whether or not. If the determination result (P _max -P _avr ) is larger than the specified value (YES), the maximum transmit power level value that can be reduced is obtained, for example, according to the value in the table shown in FIG. 4, and the result is called. Notify the control block 202 (substep SS210). That is, a value obtained by subtracting the power level value of the maximum transmission power P _max obtained by the maximum transmission power determination unit 226 from the currently allocated maximum transmission power value P _{c_max} is used as the transmission / reception management unit 236 and the call management unit 240. To the total transmission power management unit 244 via

By the above operation, the call control block
The total transmission power management unit 244 of 202 receives the maximum transmission power and the reduced power level from each radio channel control block 200, and manages the total transmission power in a state where the total transmission power can be reduced (move to subroutine SUB3).

When the determination result (P _max -P _avr ) is equal to or less than the specified value (NO), the determination result is not larger than the specified value, although it is larger than the maximum transmission power level value P _max. It is determined that the transmission power allocation has not reached the possible level. As a result, the process returns to the return without notifying the call manager 240 of the maximum transmission power level value. After the return, the subroutine SUB2 ends.

Now, transmission power control when a transmission power allocation request is issued as shown in FIG. 8 will be described. If there is a new call or a request to increase transmission power allocation,
At SS300, call management section 240 inquires of total transmission power management section 244 whether there is any transmit power that can be allocated. If there is transmit power that can be allocated (YES), sub-step SS
At 302, the transmission power is allocated to a new call or a call requesting an increase.

If there is no transmit power that can be allocated in sub-step SS300 (NO), sub-step SS30
Proceed to 4. In this case, total transmission power management section 244 determines whether there is a call whose transmission power can be reduced, and further determines whether total transmission power can be further reduced. If the total transmission power can be reduced (YES), the call management unit 240 is notified of transmission power reduction control. As a result, first, the call manager 240
In sub-step SS306, the transmission power required for a new call or a call requesting an increase is allocated. On the other hand, if it is not possible to reduce the total transmission power (NO), the process returns to the subroutine SUB3 and ends.

After that, the call management section 240
Proceed to 308. The call management unit 240 searches the call state storage unit 242 to determine whether or not there is a mobile station approaching its own station from among the communication channels that have been notified so far and whose transmission power can be reduced. As a result, if there is a mobile station approaching its own station (YES), it instructs the maximum transmission power determination unit 226 of the communication channel to reduce the maximum transmission power allocation to a power level that can be reduced ( Sub-step SS310
). At this time, the call management unit 240
The reduced surplus power level of the call to be reduced is subtracted from the total value of the reduction levels managed by. First, the reason why the transmission power is reduced from the approaching mobile station is that even if the transmission power is reduced, there is the lowest possibility of causing a call loss.

In sub-step SS308, as a result of searching the call state storage section 242, if there is no mobile station approaching (NO), the procedure moves to sub-step SS312, where a certain distance from the own station which has hardly moved. Reduce the allocation of the maximum transmission power from the mobile station located at.

After each processing in sub-steps SS302, SS310, and SS312, the processing procedure is changed to sub-step SS
Move to 314. As the processing here, the total transmission power management unit 244 determines that the total value of the maximum transmission power is a specified value (upper limit value).
Is determined. As a result, if the sum of the maximum transmission power still exceeds the specified upper limit (NO),
Returning to sub-step SS308, in the same manner as described above, a call of another approaching mobile station is detected, and the allocation of the maximum transmission power is reduced. And again sub-step SS
At 314, the operation of reducing the maximum transmission power is continued until the total of the maximum transmission power falls below the prescribed upper limit. If the sum of the maximum transmission powers is less than the prescribed upper limit (YES), it is determined that the appropriate total transmission power has been allocated, and the process returns to the subroutine SUB3.

As described above, according to the total transmission power control method of the base station and the base station apparatus in the CDMA mobile communication system according to the present embodiment, each radio channel control block
At 200, the distance from the own station to the mobile station is measured at a predetermined cycle by the distance measuring unit 218 based on the propagation time of the most advanced wave from the mobile station, and the optimum is determined according to the measured distance. Since the maximum transmission power is determined by the maximum transmission power determination unit 226 and the transmission power of each call is managed by the call control block 202 based on the result, it is necessary to allocate extra transmission power to each call. Therefore, it is possible to efficiently control the total transmission power.

In particular, when a new call is generated, the mobile station notifies its own station based on the comparison result from the distance comparison section 224 of each radio channel control block 200 in the call management section 240 of the call control block 202. It monitors whether it is approaching, or whether it is stopped or distant, preferentially reducing its transmission power allocation from mobile stations approaching its own station, and moving away from its own station. Since the transmission power is not inadvertently reduced from the mobile station, the occurrence of those call losses can be effectively suppressed.

Next, another embodiment of the total transmission power control method of the base station in the CDMA mobile communication system according to the present invention is shown (see FIGS. 9 to 12). The total transmission power control method according to the present embodiment is different from the above-described embodiment in that the total transmission power is controlled by reducing the surplus transmission power from a mobile station approaching its own station or a mobile station at a certain distance. In addition to the above points, if the total transmission power is still insufficient, the transmission power is reduced and the total transmission power is reduced for mobile stations that are not performing transmission power control among mobile stations that are performing soft handoff. The point is that the shortage of power is eliminated.

In order to facilitate understanding of the total transmission power control method according to the present embodiment, the state of soft handoff will be described first with reference to FIG. It is moving from the service area of the base station 25 to the service area of the second base station 27. At this time, it moves away from the first base station 25 and approaches the second base station 27. In this state,
For example, the first base station 25 has a frame error rate (FER) from the mobile station 15 of 30%, the second base station 27 has a frame error rate of 1%, and the mobile station 15 has a frame error rate of 1%. ing. Thereby, the first base station 25
The mobile station 15 is instructed to increase the power by
A power reduction instruction is issued from the base station 27 to the mobile station 15 (closed loop). The mobile station 15 has two base stations 25,
Since the radio wave from 27 is received, a power reduction instruction is generated (outer loop).

In this case, when the total transmission power control method of the above embodiment is applied, the transmission power control on the side of the first base station 25 cannot reduce the maximum transmission power to the mobile station 15, but the second
Is determined that the base station 27 can reduce the transmission power.
In this state, the mobile station 15 is in a state where power control is performed by the second base station 27, and the first base station 25 performs power control information between the mobile station 15 and the second base station 27. This is a case where a request to reduce transmission power is received from the mobile station 15 because the (TPC bit) is received.

In such a case, the present embodiment has a function of temporarily lowering the maximum transmission power from the first base station 25 to the mobile station 15 and allocating transmission power to another call. , To reduce the allocated power with a low call blocking rate. The base station apparatus to which the total transmission power control method of the present embodiment is applied includes, in the call management unit 240, an identification function for identifying a call during soft handoff and another call, and a call during soft handoff to the local station. The function includes a determining function of determining whether the call is controlled by a mobile telephone, a reduction instruction function of instructing power reduction based on the determination result, and a monitoring function of monitoring a call during soft handoff.

In such a configuration, according to the present embodiment,
A total transmission power control method of a base station in a CDMA mobile communication system will be described. In this case, power control is performed so as to correspond to the non-handoff processing in FIG. 8 and the handoff processing in the present embodiment, respectively (subroutine SUB4). FIG.
As shown in (1), first, the call management unit 240 of the base station apparatus includes:
With the occurrence of the new call, information about the call during the soft handoff is notified from the base station controller (substep SS400). As a result, the call management unit 240 identifies each call and sets the call in the soft handoff state in the call state storage unit 242. Next, in sub-step SS402, the call management unit 240
Inquire of 4 whether transmission power can be allocated to a new call. If there are sufficient resources (NO), the transmission power required for the new call is allocated, and resource reservation OK is returned to the base station controller (substep SS404). Also,
If sufficient transmission power cannot be allocated to a new call (YES), the process proceeds to subroutine SUB3. That is, the call management unit 240 performs the power reduction process on the call that is not in the soft handoff state according to the above-described procedure, thereby reducing the excess power of the transmission power to the approaching or stopped mobile station. Execute.

Next, the call management unit 240
4 to determine whether or not the total transmission power has been secured (substep SS406). As a result, if the transmission power is secured (NO), the sub-step
SS404 returns the resource reservation OK to the base station controller.

Further, when it is determined that the total transmission power is insufficient (YES), the transmission power reduction processing is performed for a call during soft handoff described later (subroutine SU).
B5). As a result, it is determined again whether or not the total transmission power has been secured (sub-step SS408). If the transmission power has been secured (NO), a resource reservation OK is returned to the base station controller in sub-step SS404 in the same manner as described above. If the transmission power cannot be secured (YES), sub-step SS410
Returns a resource reservation NG to the base station controller.

Next, with reference to FIG. 11, a description will be given of a process in which the call management unit 240 identifies a mobile station during soft handoff, which is a power reduction target (subroutine SUB5). First, the call manager 240 identifies a call in a soft handoff state among the respective calls (substep SS500). After identifying the call in the soft handoff state, the call manager 240 determines whether the mobile station is moving away from the mobile station (sub-step SS502). If it is approaching its own station (current base station) (NO), the call is deleted from the transmission power reduction target in sub-step SS504.

When the call management section 240 determines that the mobile station in the soft handoff state is moving away from the own station (YES), the call state storage section 242 checks the current transmission power value of the call. (Substep SS506). Then, it is determined whether or not the transmission power value is smaller than a predetermined value (substep SS508). If the transmission power is not less than the predetermined value (NO), the call is deleted from the transmission power reduction target in sub-step SS504. When the transmission power is smaller than the predetermined value (YES), the reception level is checked, and the ratio SIR of the desired wave reception power to the interference wave reception power is checked (substep SS510).

Next, in sub-step SS512, it is determined whether or not the SIR value satisfies the required SIR, and whether or not the reception level satisfies the required level. If the reception level satisfies the required level (NO), the call is deleted from the transmission power reduction target in sub-step SS104. If the reception level does not satisfy the required level (YES), the sub-step SS514 sets the transmission power to the mobile station to be reduced.

As a result, the transmission power is instructed to reduce the transmission power even though the distance to the own station is long, so that the transmission power becomes smaller than the predetermined value and the actual transmission power is reduced.
A mobile station whose SIR value does not satisfy the required SIR is regarded as a mobile station during soft hand-off that is not controlled by the own station, and is set as a mobile station for which the maximum transmission power is to be reduced. The identification result is set in the call state storage unit 242 via the call management unit 240, and when the total transmission power is insufficient, the transmission / reception management unit 236 is instructed to reduce the transmission power during soft handoff. Is done.

Next, another embodiment of the transmission power control for the transmission / reception manager 236 will be described. As a more specific example, a case where a call in a soft handoff state is monitored and power control is performed will be described as a subroutine SUB6 (see FIG. 12). First, in sub-step SS600, transmission / reception management section 236 having received an instruction from call management section 240 instructs maximum transmission power determination section 226 to reduce the maximum transmission power during soft handoff.

Next, the transmission / reception management unit 236 includes the distance comparison unit 22
It is checked whether the moving direction of the mobile station notified from 4 is the approaching direction (substep SS602). As a result, when the mobile station is moving away from the own station (NO), the monitoring state is continued (substep SS604), and the process returns to substep SS602 to check the moving direction.

If it is determined in sub-step SS602 that the mobile station is approaching the base station (own station) (YES), transmission / reception management section 236 is used to return from power control during soft handoff. Sends a release request for maximum transmission power reduction to the call management unit 240 (substep SS60).
8). In response, the call management unit 240 inquires of the total transmission power management unit 244 about the transmission power resource, and returns the result to the transmission / reception management unit 236.

Next, the transmission / reception management section 236 determines whether or not the release response is OK in sub-step SS126. If the release response is OK (YES), the process returns to normal transmission power control (substep SS612). When the release response becomes NG (NO), the flow proceeds to sub-step SS604, and again
The monitoring process of the distance tendency between the mobile station and the base station is repeated.

As described above, according to the total transmission power control method and the base station apparatus of the base station in the CDMA mobile communication system of the present embodiment, call management section 240 responds to a call in a soft handoff state by another call. Whether the power is controlled by the base station,
By judging whether or not the own station performs power control, the transmission power is reduced for a call during soft handoff in which another base station is performing power control, so that the power resources are effectively used. Thus, when the total transmission power is insufficient, the total transmission power control can be effectively executed.

FIG. 13 shows still another embodiment of the total transmission power control method of the base station in the CDMA mobile communication system according to the present invention. The total transmission power control method according to this embodiment is different from the above embodiments in that, when the call management unit 240 receives an abnormal termination of a call notified from the base station control device, By modifying the optimal maximum transmission power value of the maximum transmission power table based on the distance and the transmission power, the maximum transmission power table is dynamically updated to execute more effective total transmission power control. is there.

For example, the base station apparatus applied to the total transmission power control method according to the present embodiment includes, in addition to the configuration of each of the above embodiments, a call management unit 240 for reporting abnormal termination notified from the base station control apparatus. The detection function to detect, and the number of times of abnormal termination, the maximum transmission power at that time and the call state storage unit 242 for each distance
And a counting function to calculate the rate of occurrence of anomalies for each distance by counting the number of times, and when the result exceeds a predetermined number, increases and corrects the maximum transmission power value for each distance, and transmits that value to the maximum And a table rewriting function for updating the power table 228.

In such a configuration, according to the present embodiment,
A total transmission control method of a base station in a CDMA mobile communication system will be described. As shown in subroutine SUB7 of FIG. 13,
If the call ends abnormally in the operating state,
The base station controller notifies the call manager 240 of the base station apparatus of the abnormal termination of the call (substep SS700).
). Upon receiving the abnormal termination of the call, the call management unit 240 reads the distance from the local station to the mobile station at that time and the transmission power value from the call state storage unit 242, and acquires information on the abnormally terminated call ( Sub-step SS702).

Next, call management section 240 determines whether or not the transmission power value at the time of abnormal termination has increased to the assigned maximum transmission power (sub-step SS704). If it is determined that the transmission power of the abnormally terminated call has risen to the assigned maximum transmission power (YES), the call management unit 240 determines in step SS146 that the mobile station and the mobile station have failed to allocate the maximum transmission power. The number of failures is recorded in the call state storage unit 242 for each of the distances (substep SS706).
). If the transmission power of the abnormally terminated call has not risen to the allocated maximum transmission power (NO), the process shifts to return and ends the subroutine.

After the number of failures is recorded in the call state storage unit 242 for each distance from the mobile station, the call management unit 240
Determines whether or not the occurrence rate of abnormal termination of a call due to a failure in allocating the maximum transmission power at each distance is equal to or greater than a specified value (substep SS708). As a result, when the occurrence rate of abnormal termination of the call due to a failure in allocating the maximum transmission power in the distances x _{n to} x _{n + 1} is equal to or higher than a specified value (YE
S), the distance x _n ~x _{n + 1} of the optimum maximum transmission power value Y _{n + 1} and (Y
_{(n + 1} + Z) (substep SS710). In this case, the correction value Z is a value that satisfies Z <(Yn _{+ 2−} Yn _{+ 1} ).
Then, when the optimum maximum transmission power value is corrected in sub-step SS710, call management section 240 updates each maximum transmission power table 228 via transmission / reception management section 236.
After this update, the subroutine SUB7 ends via return.

Thereafter, the respective radio channel control blocks 20
In 0, the maximum transmission power according to the distance of each mobile station is determined based on the updated maximum transmission power table 228, and the call control block 202 controls the total transmission power based on the updated maximum transmission power. .

As described above, according to the total transmission power control method and the base station apparatus of this embodiment, the maximum transmission power table 228 for determining the optimum maximum transmission power value from the distance from the own station to the mobile station. Is updated based on the relationship between the execution result of the total transmission power control and the blocking loss rate, so that the optimum maximum transmission power for the distance of the mobile station can be more appropriately obtained, and the total transmission power control with a smaller blocking loss rate is performed. Can be.

Although the embodiments of the mobile communication system according to the present invention have been described, the present invention is not limited to the above-described embodiments, and changes in a range that does not depart from the gist of the present invention are of course included in the present invention. included.

[0078]

As described above, according to the total transmission power control method and the base station apparatus of the base station in the CDMA mobile communication system of the present invention, the propagation time of the received wave is obtained, and from the measurement result, Since the distance to the mobile station is measured and the optimal maximum transmission power for each channel is managed based on the result, it is possible to efficiently control the total transmission power without allocating extra transmission power. it can. In particular, when a new call occurs, it is monitored whether the mobile station is approaching the mobile station, or whether the mobile station is stopped or away from the mobile station, and the mobile station approaching the local station is prioritized. Since the allocation of the transmission power is reduced and the transmission power is not carelessly reduced from the mobile station moving away from the own station, it is possible to obtain an effect that the occurrence of the call loss can be suppressed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a base station device in a CDMA mobile communication system according to the present invention.

FIG. 2 is a CD to which the base station device according to the embodiment of FIG. 1 is applied;
FIG. 2 is a diagram illustrating a system configuration example of an MA mobile communication system.

FIG. 3 is a diagram illustrating a creation image of a maximum transmission power table applied to the embodiment in FIG. 1;

FIG. 4 is a diagram illustrating an example of a maximum transmission power table applied to the embodiment in FIG. 1;

FIG. 5 is a main flowchart schematically illustrating an operation of the base station apparatus according to the embodiment of FIG. 1;

FIG. 6 is a flowchart of a subroutine SUB1 applied to the base station device according to the embodiment of FIG. 1;

FIG. 7 is a flowchart of a subroutine SUB2 applied to the base station device according to the embodiment of FIG. 1;

FIG. 8 is a flowchart showing a total transmission power allocating procedure of a subroutine SUB3 applied to the subroutine SUB2 of FIG. 7;

FIG. 9 is a diagram for explaining soft handoff applied to total transmission power control of a base station.

FIG. 10 is a flowchart illustrating another procedure of total transmission power control of the base station.

FIG. 11 is a flowchart showing an example of a transmission power reduction control during handoff in the total transmission power control of the base station.

FIG. 12 is a flowchart illustrating an example of a process of power control by the transmission / reception management unit in the total transmission power control of the base station.

FIG. 13 is a flowchart showing a procedure for updating a maximum transmission power table in total transmission power control of a base station.

[Explanation of symbols]

 200 Radio line control block 202 Call control block 218 Distance measurement unit 222 Distance storage unit 224 Distance comparison unit 226 Maximum transmission power determination unit 228 Maximum transmission power table 230 Surplus power calculation unit 232 Transmission power determination unit 236 Transmission / reception management unit 240 Call management unit 242 Call state storage unit 244 Total transmission power management unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K022 EE01 EE21 5K067 AA25 BB04 CC10 DD11 EE02 EE10 EE24 FF02 GG08 GG09 HH23 JJ36 JJ39 KK15

Claims (10)

[Claims] 1. A total transmission power control method for a base station in a CDMA mobile communication system in which a radio link is set up with a plurality of mobile stations by code division multiple access and communication is performed while controlling its transmission power. The method measures a distance from the own station to the mobile station at a predetermined cycle based on a propagation time of a received wave from the mobile station, and the mobile station approaches the own station based on the measurement result. A first step of detecting whether or not the mobile station is moving, and obtaining an appropriate maximum transmission power to the mobile station corresponding to the distance based on the measurement result of the first step; A second step of obtaining an average value of transmission power to the mobile station and obtaining surplus transmission power from the average value and the maximum transmission power; and newly allocating transmission power by a new call or a request to increase transmission power. Without If no al, to reduce the surplus transmission power obtained by said second step from the transmission power to the mobile station is approaching the own station detected by said first step,
And a third step of allocating the surplus transmission power to a new request. The method of controlling the total transmission power of a base station in a CDMA mobile communication system. 2. The method according to claim 1, wherein the third step further comprises: when a total transmission power is insufficient.
A fourth step of reducing the surplus transmission power obtained in the second step from the transmission power to the mobile station whose distance from the own station detected in the first step is constant. A method for controlling total transmission power of a base station in a CDMA mobile communication system. 3. The method according to claim 1 or 2, further comprising, if the total transmission power is insufficient, distinguishing between a call during soft handoff and a call other than the soft handoff call. A fifth step of detecting whether or not the mobile station is a mobile station whose transmission power is controlled by the own station; and a software which does not control the transmission power of the own station based on the detection result of the fifth step. And a sixth step of reducing transmission power to the mobile station during handoff. 6. A method of controlling total transmission power of a base station in a CDMA mobile communication system. 4. The method according to claim 3, wherein the fifth step comprises the step of detecting whether the mobile station is moving away from the mobile station, and the transmission power to the mobile station being higher than a predetermined value. Detecting whether it is small, measuring the reception level from the mobile station, based on the measurement result whether the desired signal reception power to interference wave reception power ratio satisfies a predetermined level Detecting that the transmission power is smaller than a predetermined value even though the mobile station is away from the mobile station, and the ratio of the desired signal reception power to the interference wave reception power Making the transmission power to the mobile station during soft handoff not satisfying the predetermined level a power reduction target.
A total transmission power control method for a base station in a CDMA mobile communication system. 5. The method of claim 3, wherein the sixth step detects whether the mobile station is approaching the mobile station after setting a power reduction for a call during soft handoff. And, as a result, when the mobile station is moving away from the own station, monitoring until the mobile station hands off to another base station; and, when the mobile station is approaching the own station, reducing the transmission power to the mobile station. Canceling and returning to normal transmission power control. A total transmission power control method for a base station in a CDMA mobile communication system. 6. The method according to claim 1, wherein in the second step, an appropriate maximum transmission power to the mobile station with respect to a distance from the own station is determined in advance. Creating a maximum transmission power table representing the relationship; and updating the maximum transmission power table based on the relationship between the result of the total transmission power control and the blocking rate. A total transmission power control method for a base station in a communication system. 7. A plurality of radio channel control blocks for controlling respective radio links set with a mobile station by code division multiple access, and a call for allocating a call to the radio channel control block and controlling each call. A base station apparatus in a CDMA mobile communication system including a control block, wherein the radio channel control block sets a distance between the mobile station and the mobile station to a predetermined cycle based on a propagation time of a received wave from the mobile station. Distance measuring means for measuring the distance, moving direction detecting means for detecting whether or not the mobile station is approaching the own station based on the measurement result of the distance measuring means, and moving direction of the mobile station, and measurement of the distance measuring means. A maximum transmission power determining means for determining a maximum transmission power to the mobile station based on a result; and obtaining an average value of transmission power to the mobile station at the present time, and calculating the average value and the maximum value. Surplus power calculating means for obtaining surplus transmission power from the maximum transmission power from the transmission power determining means, wherein the call control block has to newly increase transmission power due to a new call or a request to increase transmission power. And a call management means for reducing the surplus power obtained by the surplus power calculation means from the transmission power to the mobile station approaching the own station detected by the movement direction detection means, and allocating the surplus power to a new request. A base station apparatus in a CDMA mobile communication system. 8. The apparatus according to claim 7, wherein said call management means further comprises:
The surplus power calculated by the surplus power calculation means is reduced from the transmission power to the mobile station whose distance from the own station detected by the movement direction detection means is constant.
A base station device in a CDMA mobile communication system. 9. The apparatus according to claim 7, wherein the call management means identifies a call during soft handoff and a call other than the soft handoff, among the mobile stations during soft handoff. A determining unit for determining whether or not the own station is a mobile station controlling transmission power; furthermore, when the total transmission power is insufficient, the own station determines whether the transmission power is A base station apparatus in a CDMA mobile communication system, characterized in that transmission power to the mobile station during soft handoff, which is not controlled, is reduced and assigned to a new request. 10. The apparatus according to claim 7, wherein the apparatus determines a maximum transmission power to a mobile station corresponding to a distance from the mobile station to the mobile station. A base station apparatus in a CDMA mobile communication system, comprising: a transmission power table; and a table updating means for updating the maximum transmission power table based on a result of total transmission power control and a call blocking rate.