JP3394520B2 - Transmission power control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to CDMA (code division multiple access) system transmission power control in land mobile communications.

[0002]

2. Description of the Related Art For CDMA system transmission power control in land mobile communications, for example, International Application Publication No. W
O91 / 07037 and Japanese Patent Application Publication No. 7-283783. In the CDMA system, when the level of a signal from a mobile station close to the base station is high on the uplink from the mobile station to the base station, a near-far problem occurs in which signals from other mobile stations cannot be received. Therefore, it is necessary to control the transmission power of the mobile station so that the base station receives a signal at the same level from any mobile station. Transmission power control is said to be an essential technique for solving the near-far problem and increasing the subscriber capacity. In the CDMA system, in order to mitigate the near-far problem, the base station controls the transmission power of the mobile stations in communication so that the radio waves from all the mobile stations have a uniform reception level at the base station. Since all mobile stations communicate on the same frequency, they interfere with each other. The quality of communication is determined by this interference, but in order to increase the subscriber capacity, the transmission power from the base station is set so that the radio waves from a specific mobile station do not interfere with other mobile stations. Transmit with the lowest power that can guarantee communication quality. Such transmission power control is performed by two means, that is, open loop control for estimating the transmission power by the mobile station alone and closed loop control for performing fine adjustment by a command from the base station.

FIG. 29 is a block diagram of a conventional transmission power control apparatus. The base station 101 and mobile station 102 form a closed loop control system. Although the open loop control system of the mobile station is not shown, it is assumed that the open loop control always operates to control the transmission power. The base station 101 generates a transmission power control command (hereinafter referred to as TPC bit) from the received power from the mobile station and transmits it to the mobile station. First, in the adder 103, a predetermined reference SIR (signal power to noise power ratio) (d
B) from the base station reception SIR (dB) (not shown, the reception power from the mobile station is received S by a known method).
It can be converted to IR. Hereinafter, simply the reception SIR
Power control error ε (dB)
Is obtained and supplied to the determiner 104. In the determiner 104, a value (± 1) corresponding to the sign of the power control error ε (dB)
To generate. For example, if reference SIR> reception SIR,
It is necessary to give a command to increase the transmission power to the mobile station, and the TPC bit is set to +1. If the reference SIR ≦ reception SIR, it is necessary to issue a command to reduce the transmission power to the mobile station, and the TPC bit is set to -1. TPC
The bit is a 1-bit command that has meaning only in the code, and although not shown in the figure, it is multiplexed and transmitted on the traffic channel to the mobile station. The transmission rate is several hundreds to several kilobits / second. + In actual 1-bit transmission
1 corresponds to 0 and -1 corresponds to 1.

The mobile station 102 receives the TP from the base station 101.
The closed loop control is performed by increasing or decreasing the transmission power value by a predetermined step size Δ (dB) according to the C bit. Here, the step size Δ is a fixed value, and takes a value of 1 dB, for example. First,
The mobile station 102 extracts the TPC bit from the traffic channel. The command +1 or -1 is the amplifier 1
It is multiplied by Δ in 05 and + Δ (dB) or −Δ
(DB). This value is integrated in an integrating unit composed of the adder 106 and the delay circuit 107.
For example, the initial value is 0 (dB) and the TPC bits are {+1, +1, +1, +1, -1, +1, -1, -1}.
, The output of the adder 106 is {(0), + Δ,
+ 2Δ, + 3Δ, + 4Δ, + 3Δ, + 4Δ, + 3Δ, +
2Δ}. The output value of the adder 106 is added to the power estimated as optimum by an open loop control system (not shown) as power controlled by the closed loop control system, and transmitted from the mobile station 102.

[0005]

The delay from the output of the TPC bit from the base station to the change of the transmission power of the mobile station by the TPC bit until the transmission power of the mobile station is input to the base station as the reception power. FIG. 30 shows the transmission power control fluctuation characteristics when there is no (hereinafter referred to as control delay). The horizontal axis represents time t, and the cycle in which the power control command is output (hereinafter referred to as the TPC cycle) is represented by T. The vertical axis is the reception SIR from the mobile station at the base station. 401-4
Reference numeral 04 indicates a reception SIR. 501 to 504 are reception SIRs
40 to 404, the TPC bits generated by the base station are shown. As shown in FIG. 30, the variation of the received SIR with respect to time t (the reference value is 0) varies within the reference value ± Δ if the variation in 1T is within 1Δ.
That is, in FIG. 30, since the reception SIR 401 <0, the TPC bit 501 becomes +1. As a result, the reception SIR 402 has a value that is larger than the reception SIR 401 by approximately Δ. Next, since the reception SIR 402 ≧ 0,
The TPC bit 502 becomes -1. As a result, the received SI
R403 is a value that is smaller than reception SIR 402 by approximately Δ. Hereinafter, the same operation is repeated. From FIG. 30, it can be seen that the variation of the base station reception SIR is within the reference SIR ± Δ. FIG. 31 shows the transmission power control variation characteristic when the control delay is 1T, and the vertical axis and the horizontal axis are the same as those in FIG. When the control delay (1T) exists, as shown in FIG. 31, the variation of the received SIR with respect to time t varies within the reference value ± 2Δ even though the variation of the received SIR at 1T is within 1Δ. To do. That is, in FIG.
Since there is the control delay 1T, the reflection of the TPC bit to the reception SIR is delayed by 1T as compared with FIG. For example, since the reception SIR 411 <0, the TPC
Bit 511 becomes +1. TPC bit 51 1T before
Since 0 is +1, the reception SIR 412 is the reception SIR.
The value is larger than 411 by about Δ. Next, receive SI
Since R412 ≧ 0, the TPC bit 512 becomes −1. Since the TPC bit 511 1T before is +1,
The reception SIR 413 has a value larger than the reception SIR 412 by approximately Δ. Next, since the reception SIR 413 ≧ 0, the TPC bit 513 becomes −1. TPC 1T before
Since the bit 512 is -1, the reception SIR 414 is
The value is smaller than the reception SIR 413 by about Δ. Hereinafter, the same operation is repeated. From FIG. 31, the base station reception S
It can be seen that the fluctuation of IR is within the reference SIR ± 2Δ. When the control delay is 2T or more, the transmission power fluctuation becomes further large. Since the conventional transmission power control apparatus is configured as described above, when the control delay is 1 or more, the parasitic variation due to the control delay is caused even though the variation in the received power of the channel is almost static. Will occur. As a result, there is a problem that the power control error increases and the subscriber capacity decreases.

Further, the conventional transmission power control device is
The bit step size Δ is fixed. As a result, depending on the moving speed of the mobile station, there is a problem that the power control error increases and the subscriber capacity decreases. FIG. 32 is a diagram showing transmission power control error characteristics,
The horizontal axis is fDT (fD is Doppler frequency, T is TPC cycle), the vertical axis is the standard deviation σ of the transmission power control error, and the control delay is 1T. The Doppler frequency fD corresponds to the speed of the mobile station. For example, the transmission frequency is 1 GH.
In the z band, when the moving speed of the mobile station is 100 km / h, the Doppler frequency fD is 90 Hz. Therefore,
If the TPC cycle T is 1.1 kbps, fDT = 0.1. The characteristic A and the characteristic B have different step sizes, and the step size Δ1 of the characteristic A is smaller than the step size Δ2 of the characteristic B. For example, the characteristic A step size Δ1 = 0.5 dB, and the characteristic B step size Δ
It takes a value of 2 = 1 dB. From FIG. 32, fDT is 0.
When 01, characteristics A (Δ = Δ1 dB) and characteristics B (Δ2d
It can be seen that the characteristics are reversed in B). Therefore, f
When DT ≦ 0.01, the characteristic A (Δ = Δ1 dB) has a smaller transmission power control error, and when fDT> 0.01, the characteristic B (Δ = Δ2 dB) has a smaller transmission power control error.

In the conventional transmission power control apparatus, it has been proposed that the TPC bit is transmitted in multiple bits instead of one bit, but in the case of multiple bits, the TPC bit from the base station to the mobile station is transmitted. Another problem is that the transmission rate increases.

Further, since the conventional transmission power control device follows the step size Δ even for abrupt channel power fluctuations, there is a problem that interference with the system becomes very large. It was In FIG. 33, the horizontal axis represents time t and the vertical axis represents the reception SIR of the base station. A dotted line 601 represents the fluctuation of the transmission power of the channel, and a solid line 602 represents the fluctuation of the reception SIR of the base station. The interference to the system becomes a problem that the fluctuation of the transmission power of the channel (dotted line 601) causes the reception S of the base station.
It is time to exceed the range of power control by IR.
When giving a big interference to the system, specifically,
After the base station commands the mobile station to increase the transmission power due to the drop in the received SIR due to fading as shown in FIG. 33, the drop in the received SIR due to fading is recovered, and the transmit power is already sufficient power. ,
This is a case where the transmission power value does not reach the predetermined value (below). This is because the step size Δ is smaller than the variation and the control delay exists.

[0009]

A transmission power control apparatus according to the present invention is a code division multiple access (C) from a transmission station to a reception station.
In the transmission power control device for controlling the transmission power of the transmission station when performing data transmission by the DMA system, the reception station controls the transmission power of the transmission station based on the received transmission power from the transmission station. The transmission station includes a command generation unit that generates a power control command and transmits the power control command to the transmission station, and the transmission station includes a transmission power control unit that receives the transmission power control command and controls the transmission power based on the transmission power control command. The command generation unit is characterized by generating a transmission power control command based on the received transmission power from the transmission station and the transmission power control command already transmitted to the transmission station.

In the command generating section, after the transmitting station transmits a certain transmission power control command to the receiving station, the receiving station changes the transmitting power of the transmitting station based on the transmitting power control command, and the transmitting power is changed. If there is a delay time before input to the receiving station, the transmission generated from the received transmission power based on the control contents by the transmission power control command transmitted from the transmitting station to the receiving station during the delay time. It is characterized in that a correction unit for correcting the power control command is provided.

The command generation unit determines an adder that takes a difference between the transmission power from the transmission station and a predetermined reference power and outputs a power control error, and determines whether the transmission power of the transmission station increases or decreases from the power control error. And a determiner that outputs a transmission power control command. The correction unit corrects the power control error by inputting the transmission power control command output from the determiner.

The correction unit inputs a transmission power control command, delays the transmission power control command by delaying by the delay time, and outputs a transmission power control command, and inputs the transmission power control command output from the delay circuit. The receiver includes an amplifier that generates and outputs the same increment as the increment of the transmission power that is generated by inputting the transmission power control command, and an adder that adds the increment output from the amplifier to the power control error. Is characterized by.

The command generation unit receives an difference between the transmission power from the transmission station and a predetermined reference power and outputs a power control error, and an input of the power control error based on the value of the power control error. It is characterized by having a control algorithm for outputting a transmission power control command.

The transmission power control apparatus according to the present invention is the transmission power control apparatus for controlling the transmission power of the transmission station when data is transmitted from the transmission station to the reception station by the code division multiple access (CDMA) method. The receiving station includes a command generating unit that generates a transmission power control command for controlling the transmission power of the transmitting station based on the received transmission power from the transmitting station and transmits the command to the transmitting station. A transmission power control unit that receives a control command and controls the transmission power based on the transmission power control command is provided, and the transmission power control unit is a first step size and a second step size that are units for increasing or decreasing the transmission power. Is stored, and the first step size and the second step size are dynamically switched to control increase / decrease in transmission power.

The transmission power control section detects the moving speed of the transmitting station, and the first step size and the second step size based on the moving speed of the transmitting station detected by the speed detecting section. And a step size determination unit that selectively determines one of them.

The speed detection unit includes a storage unit that stores the transmission power control command, and a counting unit that counts the stored transmission power control command and determines the statistical property of the transmission power control command. The size determining unit determines the first step size and the second step size based on the statistical properties of the transmission power control command determined by the counting unit.
It is characterized in that any one of the step sizes is selected and determined.

The counting unit counts the number of consecutive transmission power control commands.

The counting unit counts the number of consecutive transmission power control commands.

The transmission power control apparatus according to the present invention is the transmission power control apparatus for controlling the transmission power of the transmission station when data is transmitted from the transmission station to the reception station by the code division multiple access (CDMA) method. The receiving station includes a command generating unit that generates a transmission power control command for controlling the transmission power of the transmitting station based on the received transmission power from the transmitting station and transmits the command to the transmitting station. A power setting unit that receives a control command and controls the transmission power based on the transmission power control command, wherein the transmission power control unit resets the transmission power to an average value of the transmission powers transmitted in the past. It is characterized by having.

The power setting unit is controlled by a predetermined pattern detecting unit that detects that the transmission power control command occurs in a predetermined pattern, an average value of past transmission power control commands, and a past transmission power control command. Averaging unit that calculates and outputs one of the average values of the transmission power, and when the predetermined pattern detection unit detects a predetermined pattern, the control by the received transmission power control command is stopped and the averaging is performed. And a switch circuit for outputting an average value output from the unit.

The predetermined pattern is characterized in that the transmission power control command instructing the power decrease comes after a predetermined number of consecutive transmission power control commands instructing the power increase.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. 1 is a block diagram of a first embodiment according to the present invention. In FIG. 1, the base station 101 and the mobile station 102 constitute a closed loop control system for power control. Although the open loop control system of the mobile station is not shown, it is assumed that the open loop control system always operates to control the transmission power. After the TPC bit is output from the base station,
The delay (hereinafter referred to as control delay or delay time) until the TPC bit changes the transmission power of the mobile station and the transmission power of the mobile station is input to the base station as reception power is 1T (T
Is the TPC cycle). An adder 103 takes the difference between the transmission power from the transmission station and a predetermined reference power and outputs a power control error ε. A determiner 104 determines whether the transmission power of the transmitting station is increased or decreased based on the power control error and outputs a transmission power control command (TPC bit). 18
0 is a command generation unit that generates a transmission power control command for controlling the transmission power of the transmission station based on the received transmission power from the transmission station and transmits the transmission power control command to the transmission station. A transmission power control command is generated based on the transmission power of the transmission power control command and the transmission power control command already transmitted to the transmitting station. A correction unit 181 corrects the transmission power control command generated from the received transmission power based on the control content of the transmission power control command transmitted from the transmission station to the reception station during the delay time. Reference numeral 110 denotes a delay circuit which inputs the transmission power control command, delays the transmission power control command by the delay time, and outputs the transmission power control command.
Reference numeral 109 denotes an amplifier that receives the transmission power control command output from the delay circuit and generates and outputs the same increment as the increment of the transmission power generated by the reception unit receiving the transmission power control command. An adder 108 adds the increment output from the amplifier to the power control error. Reference numeral 190 denotes a transmission power control unit that receives the transmission power control command and controls the transmission power based on the transmission power control command. In FIG. 1, in addition to the determiner 104 of the base station 101, an adder 108, an amplifier 109, and a delay circuit 110 are provided.
In the delay circuit 110, the TPC output from the determiner 104
The bit (± 1) is delayed by the control delay (1T) and output to the amplifier 109. The output of the delay circuit 110 is the amplifier 1
09 is multiplied by Δ to be + Δ or −Δ. Amplifier 10
The output of 9 is subtracted from the power control error output from the adder 103 in the adder 108, so that the decision unit 104 generates a new TPC bit.

Next, the operation of FIG. 1 will be described. As shown in FIGS. 2 and 3, the transmission power control apparatus according to the first embodiment of the present invention when there is a control delay (1T) is as follows.
The fluctuation can be within a specified range (± 1Δ). In FIG. 2, the solid line shows the control result of the present invention.
In FIG. 2, the dotted line shows the control result by the conventional transmission power control device for comparison with the present invention. Receive S
Since IR421 <0 and the TPC bit 520 1T before is +1, the output of the amplifier 109 is + Δ, and the adder 108 subtracts + Δ from the value of the reception SIR421, so the TPC output from the determiner 104. Bit 521
Is -1. Since the TPC bit 520 1T before is +1, the reception SIR 422 has a value that is larger than the reception SIR 421 by approximately Δ. Next, since the reception SIR 422 ≧ 0 and the TPC bit 521 1T before is −1, TP
The C bit 522 becomes +1. TPC bit 5 1T before
Since 21 is -1, the reception SIR 423 is the reception SIR.
The value is smaller than 422 by approximately Δ. Next, receive SI
R423 <0, and the TPC bit 522 1T before is +
Since it is 1, the TPC bit 523 becomes -1. Since the TPC bit 522 1T before is +1, the reception SIR 42
4 is a value larger than the reception SIR 423 by about Δ.
Hereinafter, the same operation is repeated.

In this way, when the control delay is 1T, a new TPC bit is created from the value obtained by subtracting the product of the transmitted TPC bit 1T before and the step size from the power control error in advance. The fluctuation due to the control delay is suppressed to ± Δ or less.

As described above, according to the present invention, when the control delay of 1T exists, the received power does not reflect the power control by the TPC bit already output 1T before, but by the already output TPC bit. Since the power control is performed later, the power control is performed by discounting the power control by the TPC bit to be performed later to remove the parasitic variation caused by the control delay.

Embodiment 2. FIG. 4 is a block diagram of the second embodiment of the present invention, and the control delay is 2T.
In FIG. 4, the delay circuit 110 of the base station 101 in FIG.
A delay circuit 118 and an amplifier 117 are inserted in parallel between the amplifier 109 and the adder 108. 5 and 6 show
It is a figure explaining operation | movement of this Embodiment. Adder 10
8 subtracts the power output from the amplifiers 117 and 109 from the received SIR output from the adder 103. That is, in this embodiment, attention is paid to the fact that the power control by the two TPC bits already output 1T before and 2T before is not reflected, and the transmission power is reflected when the power control by the two TPC bits is reflected. Is to be determined in advance, and power control is to be performed on the determination result. With this configuration, the delay in one cycle can be removed by the delay circuit 110 and the amplifier 109, and the delay in two cycles can be removed by the delay circuit 118 and the amplifier 117. Therefore, when the control delay is 2T. In addition, the received SIR fluctuation can be suppressed within ± Δ.

It is self-evident that the same effect can be obtained by configuring the same even when the control delay is 3T or more.

Embodiment 3. FIG. 7 is a block diagram of the third embodiment of the present invention, and the control delay is 1T. Figure 7
Removes the decision unit 104, the adder 108, the amplifier 109, and the delay circuit 110 in FIG.
It is shown by 19.

FIG. 8 shows a flowchart of the algorithm. In the flowchart, ε represents "base station reception SIR-reference SIR" and represents a power control error. TP
C _n represents the current TPC bit, and TPC _n-1 is 1
Represents the TPC bit before T. Also, TPC ^T is TPC
Indicates the polarity inversion of the bit. In process 201, the adder 10
Power control error ε output from 3 and TP past 1T
Input C bit. In branch 202, the power control error ε
> + Δ is determined, and if YES, process 206 is executed, and N
If O, branch 203 is further executed. At branch 203,
A power control error ε <−Δ is determined, and if YES, process 20
5 is executed, and if NO, process 204 is executed. That is, the process 205 is executed when the power control error ε <−Δ, the process 204 is executed when −Δ ≦ power control error ε ≦ Δ, and the process 206 is executed when the power control error ε> Δ. Then, in processing 204, the polarity of the new TPC bit is inverted by 1T for the past TPC bit. In the process 205, the new TPC bit is set to +1. In the process 206, the new TPC bit is set to -1. The value of the TPC bit corresponding to each case will be transmitted to the mobile station.

The process 204 of the control algorithm described above prevents the TPC bit from having the same polarity twice in succession when the control delay is 1T. That is, it is utilized that the power control is within ± Δ by removing the TPC bit 1T before the current TPC bit. Therefore, when the power fluctuation of the channel is slow, the power control error becomes small, resulting in an increase in the channel capacity. On the other hand, when the power fluctuation of the channel is steep and the control delay is 1T, the tracking characteristic is delayed by 1T as compared with the normal control. Therefore, the power control error may increase due to the sharp power fluctuation of the channel. However, when the moving speed of the mobile station is low, the occurrence frequency itself when the power fluctuation of the channel is sharp is small. It doesn't matter. Further, even if the moving speed is high, the occurrence frequency when the power fluctuation of the channel is steep can be reduced by a known technique such as RAKE reception and space diversity, and the transmission power control error characteristic can be greatly improved as a whole.

FIG. 9 shows the transmission power control error for fDT. Characteristic C and characteristic D indicate the power control error characteristic according to this method. The characteristic C corresponds to the conventional characteristic A. The characteristic D corresponds to the conventional characteristic B. By adopting this method, the power control error characteristic is greatly improved.

Fourth Embodiment In this embodiment, a case will be described in which the mobile station is provided with a means for detecting the moving speed of the mobile station, that is, fDT, and the optimum step size Δ is selected thereby. As will be described later, the detection of fDT is performed by, for example, comparing a statistic amount of received TPC bits (for example, a continuous number or a continuous number described later) averaged by a predetermined number with a reference value.

FIG. 10 shows a block diagram of a transmission power control apparatus according to Embodiment 4 of the present invention. In FIG.
A speed detection unit 182 detects the moving speed of the mobile station. Also, 192 is a speed detection unit that similarly detects the moving speed of the mobile station. In FIG. 10, the mobile station 102 in the block diagram of FIG.
Continuous number counting unit (simply also called counting unit) 11
5. A step size (Δ) determination unit 116 is added. In addition, the base station 101 is provided with a TPC bit storage unit 11
1, a continuous number / continuous number counting unit 112, and a Δ determination unit 113 are added. First, in the mobile station 102, the TPC bit storage unit 114 stores the received TPC bits by a predetermined number of bits. Stored TPC
The number of consecutive bits and the number of consecutive bits are counted by the consecutive number / consecutive number counting unit 115. The counted number of consecutive stations and the number of consecutive stations are input to the Δ determination unit 116, where a new step size Δ is determined based on the current step size Δ and the number of consecutive stations and the number of consecutive stations. Amplifier 1
At 05, the product of the determined step size Δ and the TPC bit is output. Also, the TPC bit delayed by the delay circuit 110 in the base station 101 is
The bit storage unit 111 stores a predetermined number of bits. The stored TPC bits are counted by the continuous number / continuous number counting unit 112.
The counted number of consecutive stations and the number of consecutive stations are input to the Δ determination unit 113, where a new step size Δ is determined based on the current step size Δ and the number of consecutive stations and the number of consecutive stations. The amplifier 109 outputs the product of the determined step size Δ and the TPC bit.

As shown in FIG. 32, fDT ≦ 0.01
Then, select the step size Δ = Δ1 dB, and fDT>
When 0.01, the step size Δ = Δ2 dB is selected to improve the power control error characteristic. In order to realize this, a means for measuring the moving speed of the mobile station, that is, fDT is required. In this embodiment, the statistical nature of the TPC bits is used to measure fDT. Here, as an example, the frequency of the number of consecutive TPC bits acquired in advance by simulation or actual measurement, or the frequency of the number of consecutive times and the number of consecutive times obtained by averaging the actually transmitted TPC bits with a prescribed number of symbols. Or the frequency of continuous numbers is used. Alternatively, the number of consecutive TPC bits acquired in advance by simulation or actual measurement or the number of consecutive times and the number of consecutive transmitted TPC bits or the number of consecutive times are used. Here, the number of stations is
It is the number of consecutive TPC bits of the same polarity. For example,
10 samples accumulated (number of samples S = 10)
TPC bits of {+1, +1, +1, +1, -1,-
When it is 1, -1, +1, +1, -1}, it is counted as shown in FIG. As a result, a count table (frequency table) of consecutive numbers as shown in FIG. 12 can be created. However, the denominator for obtaining the frequency of the consecutive numbers is set to the sample number S for simplicity. Further, the continuous number is a number in which N consecutive TPC bits of the TPC bits of the predetermined sample number S have the same polarity, and for example, 10 accumulated samples (sample number S = 10). TPC bit is +
1, +1, +1, +1, -1, -1, -1, +1, +
When it is 1, −1}, it is counted as shown in FIG.
As a result, a continuous count table (frequency table) as shown in FIG. 14 can be created.

FIG. 15 shows the frequency distribution (Δ = Δ1 dB) of the number of stations with respect to fDT when M = m (1 ≦ m ≦ S), and M =
FIG. 16 shows the frequency distribution (Δ = Δ2 dB) of the number of stations with respect to fDT in the case of m (1 ≦ m ≦ S). However, the denominator for obtaining the frequency of the consecutive numbers is set to the sample number S for simplicity. Further, the frequency distribution (Δ = Δ1 dB) of the continuous number with respect to fDT in the case of N = n (0 ≦ n ≦ S) is shown in FIG.
FIG. 18 shows the frequency distribution (Δ = Δ2 dB) of the continuous number with respect to fDT in the case of n (0 ≦ n ≦ S). 15 and 1
FIG. 6 is a diagram of the number of consecutive TPC bits obtained in advance by simulation or actual measurement when Δ = Δ1 dB and Δ = Δ2 dB. The horizontal axis of the figure is fDT indicating the moving speed of the mobile station. The vertical axis represents the frequency of consecutive numbers when the consecutive number M = m. The point to be noted here is that fDT = 0.
01 is the frequency of consecutive numbers. The frequency of consecutive numbers is Δ1 / S when Δ = Δ1 dB, and the frequency of consecutive numbers is α when Δ = Δ2 dB.
2 / S. Simulation, or
From the frequency distribution obtained from the actual measurement results, Δ = Δ1 dB
In the case where the power control is performed in step 1, when the frequency of the number of stations is larger than α1 / S, it can be determined that the fDT indicating the moving speed of the mobile station is 0.01 or less. Therefore, when the frequency of the number of stations is larger than α1 / S, the electric power is controlled using Δ = Δ1 dB. Also, Δ =
If the frequency of the stations is smaller than α1 / S while controlling the power using Δ1 dB, it is determined that the fDT indicating the moving speed of the mobile station is 0.01 or more. it can. When the station frequency becomes a value smaller than α1 / S, it is necessary to switch the step size. That is, power control is performed by switching to Δ = Δ2 dB. Figure 1
FIG. 7 and FIG. 18 show a case where the continuous frequency is used instead of the continuous frequency. Also in the case of FIGS. 17 and 18, Δ = Δ based on the result of simulation or actual measurement
This is a calculation of the number of consecutive TPC bits in the case of 1 dB and Δ = Δ2 dB. From this result, it is possible to determine whether the value of fDT indicating the speed of the mobile station is 0.01 or less or 0.01 or more from the values β1 / S and β2 / S of the continuous frequency. From the characteristics shown in FIGS. 15 to 18, Δ = Δ1 dB
By setting the switching standards of Δ and Δ = 2 dB as shown in FIG. 19, switching can be performed at fDT = 0.01. Further, by using both the switching frequency and the switching frequency as the switching criteria, frequent switching can be prevented.

In the description of FIGS. 15 to 19 described above, the case in which the step size is changed using the consecutive number frequency and the consecutive number frequency has been explained, but the step size is switched using the consecutive number count and the consecutive number count. You may do so. As shown in FIGS. 12 and 14, the number of consecutive counts and the number of consecutive counts divided by the number of samples S are the consecutive number frequency and the consecutive number frequency. can do.

FIG. 20 shows the Δ decision units 113 and 116.
Will be described in more detail. Here, a case where the step size is determined using the consecutive count and the consecutive count will be described. In FIG. 20, the Δ determination unit 11
6 is a comparator 301, 302, 303, 304, AND
Gate 305, NAND gate 306, selector 30
It is composed of 7,308. Assuming that the initial value of the step size Δ is Δ1 dB, the inputs of the selectors 307 and 308 are given to select the output of the AND gate 305 and Δ1 dB, respectively. The number of stations counted by the station number / continuous number counting unit 115 is calculated by the comparators 301 and 30.
3 is supplied. The comparator 301 compares the consecutive count with the reference value 1. Reference value 1 corresponds to α1 above,
The output of the comparator 301 becomes +1 when the consecutive number count <α1 and becomes −1 when the consecutive number count ≧ α1. On the other hand, the comparator 303 compares the consecutive count with the reference value 3.
The reference value 3 corresponds to the above α2, and the output of the comparator 303 becomes +1 when the number of consecutive counts ≧ α2, and becomes −1 when the number of consecutive numbers <α2. In addition, the consecutive number counted by the consecutive number / consecutive number counting unit 115 is calculated by the comparators 302 and 3
04. The comparator 302 compares the continuous count with the reference value 2. The reference value 2 corresponds to β1 described above, and the output of the comparator 302 becomes +1 when the continuous number count ≧ β1, and becomes −1 when the continuous number count <β1. On the other hand, the comparator 304 compares the continuous count with the reference value 4. The reference value 4 corresponds to β2 described above, and the comparator 30
The output of 4 is +1 when the continuous count is <β2, and is -1 when the continuous count is ≧ β2. AND gate 30
The outputs of the comparator 301 and the comparator 302 are supplied to 5, which outputs +1 when they are both +1 and outputs -1 at other times. The output of the AND gate 305 becomes +1 when the consecutive count <α1 and the consecutive count ≧
This is the case of β1. The outputs of the comparator 303 and the comparator 304 are supplied to the NAND gate 306, which outputs −1 when they are both +1 and outputs +1 otherwise.
The output of the NAND gate 306 becomes -1 when the consecutive count is ≧ α2 and the consecutive count is <β2. The selector 307 has an AND gate 305 and a NAN.
The output of the D gate 306 is supplied, and the output of the AND gate 305 is initially selected. AND gate 30
When the five outputs are −1, that is, when the consecutive number count <α1 and the consecutive number count ≧ β1 are not satisfied, the selector 307
Continues selecting the output of the AND gate 305, and the selector 3
08 also continues to select Δ = Δ1 dB. On the other hand, when the output of the AND gate 305 becomes +1, that is, when the consecutive count <α1 and the consecutive count ≧ β1 are satisfied, the selector 307 selects the output of the NAND gate 306. Then, the selector 308 determines that the step size Δ = Δ
Select 2 dB. The output of the selector 307 is NAND
After switching to the output of the gate 306, when the output of the NAND gate 306 is +1, that is, when the consecutive count ≧ α2 and the consecutive count <β2 are not satisfied, the selector 307 selects the output of the NAND gate 306. Continue to
The selector 308 also continues to select the step size Δ = Δ2 dB. On the other hand, when the output of the NAND gate 306 becomes −1, that is, when the consecutive number count ≧ α2 and the consecutive number count <β2 are satisfied, the selector 307 determines that the NAND
The output of gate 306 is selected. And the selector 30
8 selects the step size Δ = Δ1 dB. As described above, since the Δ determination unit operates, it is possible to detect fDT by using the statistical property of TPC bits. -Since the number of stations and the number of stations are observed, the measurement accuracy is improved. The switching frequency is relaxed because of the AND condition of the number of stations and the number of consecutive stations. And so on.

As another configuration of the Δ decision unit 116, FIG.
1, a configuration using an OR gate 309 instead of the AND gate 305 and a NOR gate 310 instead of the NAND gate 306, a configuration using only consecutive numbers as shown in FIG. 22, and a continuous number as shown in FIG. There is a configuration that uses only. Although the NOT gate is used in FIGS. 22 and 23 for convenience of description, the NOT gate 311 may be deleted in FIG. 22 and the input of the comparator 303 may be replaced. Also,
In FIG. 23, the NOT gate 312 is deleted and the comparator 30
The inputs of 4 may be exchanged. In addition, consecutive number count, consecutive number count, reference values 1 to 4 (α1, β1, α2, β
Instead of 2), the frequency of consecutive numbers obtained by dividing each by the number of samples, the frequency of consecutive numbers, and the reference values 5 to 8 (α1 / S, β1 / S,
(α2 / S, β2 / S) may be used.

FIG. 24 is a diagram showing another structure of this embodiment. The configuration shown in FIG. 24 is obtained by adding a speed detection unit 192 and a Δ determination unit 116 to the conventional configuration. In the case shown in FIG. 24, the step size is switched by simply detecting the moving speed of the mobile station without modifying the transmission power control command based on the control delay shown in the first embodiment. In this way, the moving speed of the mobile station is set to TP
It is possible to reduce the power control error by determining the step size by judging from the statistical properties of the C bits.

As described above, in this embodiment, the reference S
It is characterized in that the first step size Δ1 and the second step size Δ2 are switched so as to reduce the power control error which is a value obtained by subtracting the reception SIR of the base station from IR. The step size is switched by detecting the moving speed of the mobile station, selecting the first step size Δ1 when the moving speed is slow, and selecting the first step size Δ1 when the moving speed is faster than the first step size Δ1. The second step size Δ2 is selected. The moving speed is detected based on the result of comparison between the consecutive count of the transmission power control command at a predetermined time and the reference value. The moving speed is verified by the result of comparison between the continuous count of the transmission power control commands at a predetermined time and the reference value. Further, the step size determination unit switches to the second step size when the number of consecutive transmission power control commands in the first step size is equal to or smaller than the first reference value, and the transmission power control command in the second step size is changed. Is the third consecutive count
It is characterized in that it is operated so as to switch to the first step size when it is equal to or larger than the reference value of. Further, the step size determination unit switches to the second step size when the continuous count of the transmission power control commands in the first step size is equal to or larger than the second reference value, and the transmission power in the second step size is changed. It is characterized in that the control command is operated to switch to the first step size when the continuous count of the control command is equal to or less than the fourth reference value. Also, the step size determination unit determines whether the consecutive step count of the transmission power control command in the first step size is less than or equal to the first reference value and the consecutive number count is not less than the third reference value. Switch to size and then the second
When the continuous count of the transmission power control command in the step size of is equal to or larger than the second reference value and the continuous count is equal to or smaller than the fourth reference value, the operation is switched to the first step size. Characterize.

Embodiment 5. In this embodiment, means for detecting abrupt power fluctuation is provided so as to reduce interference with the system even when abrupt channel power changes, and at the time of detection, the transmission power of the mobile station is averaged using a predetermined TPC bit. The case of returning to electric power will be described. The detection of a sudden power fluctuation is performed by detecting a predetermined pattern from the accumulation of TPC bits. In the fifth embodiment, it is possible to improve the tracking characteristic with respect to fluctuations in a large fDT region, suppress interference with the system, and increase the subscriber capacity of the system.

FIG. 25 shows a block diagram of the fifth embodiment of the present invention. This is because a switch circuit including a predetermined pattern detection unit 120, an averaging unit 121, and switches 122 and 123 is newly added to the mobile station 102 of FIG.
A predetermined pattern detection unit 127, an averaging unit 128, and a switch 129 are newly added to the base station 101. In FIG. 25, 193 is a power setting unit that resets the transmission power to the average value of the transmission powers transmitted in the past. Reference numeral 120 denotes a predetermined pattern detection unit that detects that the TPC bit has generated a predetermined pattern. An averaging unit 121 calculates and outputs an average value of a predetermined number of TPC bits generated in the past. Reference numeral 194 is an amplifier that integrates the step size with respect to the average value output by the averaging unit. In the mobile station 102, the TPC bits stored in the TPC bit storage unit 114 are detected by the predetermined pattern detection unit 120 in order to detect a predetermined pattern, and the averaging unit 121 is used.
Is used to calculate the average value of TPC bits. In the predetermined pattern detection unit, the predetermined pattern [+1, +1, +
1, +1, +1, +1, +1, +1, +1, -1] is detected, +1 is output, and otherwise, -1 is output.
When the predetermined pattern is not detected, that is, when the output of the predetermined pattern detection unit 120 is -1, the switch 122 is on and the switch 123 is off. Figure 10
It has the same structure as. On the other hand, when the predetermined pattern is detected, that is, when the output of the predetermined pattern detection unit 120 is +1, the switch 122 is off and the switch 123 is on. For this reason, when the predetermined pattern is not detected, as shown in FIG.
The same operation is performed, but when a predetermined pattern is detected, the integration by the adder 106 and the delay circuit 107 is reset, and the value obtained by adding the step size to the value of the averaging unit 121 is output as the transmission power of the mobile station. . Similarly at the base station,
The predetermined pattern detection unit 127 detects the predetermined pattern and the averaging unit averages the TPC bits. The switch 129 selects the output of the amplifier 109 when the predetermined pattern is not detected, and the average when the predetermined pattern is detected. The sum of the step size and the output of the conversion unit 128 is selected.

FIG. 26 is a diagram showing the operation of the configuration shown in FIG. For example, a predetermined pattern [+1, +1, +1, +1, +1, +1, +1, +1,
+1, −1] is detected, and at that time, the average value of the TPC bits and the step size are re-set as the average value 603. It is rational that the predetermined pattern of the TPC bit is a pattern of receiving +1 after receiving +1 consecutively n times. The average value is, for example, 100T in the past.
The average value of TPC bits for PC bits may be used. As shown in FIG. 26, by setting the average value 603, the interference with the system, which has occurred conventionally, is significantly reduced.

FIG. 27 is a diagram showing another structure of this embodiment. FIG. 27 shows a conventional configuration in which a power setting unit, which is a feature of this embodiment, is added. FIG. 27
According to the configuration shown in (1), it is possible to reduce interference with the system even when the power of the channel fluctuates rapidly. In the above-described embodiment, the case where the average value of TPC bits is calculated has been described, but the average value of the transmission power output from transmission power control section 190 is used without using the TPC bits. I don't mind. In FIG. 28, reference numeral 196 is an averaging unit that stores the value of the transmission power transmitted in the past and calculates the average value. A switch 195 selects the average value output from the averaging unit 196 as the transmission power when the predetermined pattern detection unit 120 detects the predetermined pattern. As shown in FIG. 28,
It is also possible to reset the transmission power using the average value of the transmission power.

[0045]

Since the transmission power control apparatus of the present invention is configured as described above, the transmission power control error is reduced,
This has the effect of increasing the subscriber capacity of the system.

Further, according to the present invention, the correction unit can correct the transmission power control command based on the delay time.

Further, according to the present invention, the correction unit corrects the current power control error by using the transmission power control command output first, thereby performing appropriate transmission power control.

Further, according to the present invention, the correction section can be configured by hardware.

Further, according to the present invention, transmission power control can be performed by software.

Further, according to the transmission power control apparatus of the present invention, the transmission power control error is reduced by switching the step size to control the power, and the subscriber capacity of the system can be increased.

Further, according to the present invention, the step size can be switched based on the moving speed of the transmitting station.

Further, according to the present invention, the moving speed can be detected by utilizing the statistical property of the transmission power control command.

Further, according to the present invention, the moving speed of the transmitting station can be detected by counting the number of consecutive transmission power control commands.

Further, according to the present invention, the moving speed of the transmitting station can be detected by counting the number of consecutive transmission power control commands.

Further, since the transmission power control apparatus of the present invention is configured to reset the transmission power, it is possible to reduce interference with other mobile stations, so that it is possible to increase the subscriber capacity of the system. is there.

Further, according to the present invention, the transmission power can be an average value of past transmission powers.

Further, according to the present invention, it becomes possible to reset the transmission power by judging the degree of interference with another mobile station from the predetermined pattern of the transmission power control command.

[Brief description of drawings]

FIG. 1 is a block diagram showing a transmission power control device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining time variation of base station reception power when the control delay is 1T in the transmission power control apparatus according to the first embodiment of the present invention.

FIG. 3 is a diagram for explaining time variation of base station reception power when the control delay is 1T in the transmission power control apparatus according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing a transmission power control device according to a second embodiment of the present invention.

[Fig. 5] Fig. 5 is a diagram for explaining time variation of base station reception power when the control delay is 2T in the transmission power control apparatus according to the second embodiment of the present invention.

[Fig. 6] Fig. 6 is a diagram for explaining time variation of base station reception power when the control delay is 2T in the transmission power control apparatus according to the second embodiment of the present invention.

FIG. 7 is a block diagram showing a transmission power control device according to a third embodiment of the present invention.

FIG. 8 is a flowchart diagram illustrating a control algorithm of the transmission power control apparatus according to the third embodiment of the present invention.

FIG. 9 is a diagram showing transmission power control error characteristics of the transmission power control device of the present invention.

FIG. 10 is a block diagram showing a transmission power control device according to a fourth embodiment of the present invention.

FIG. 11 is a diagram illustrating the number of stations of the present invention.

FIG. 12 is a diagram showing a frequency distribution of consecutive numbers according to the present invention.

FIG. 13 is a diagram illustrating a continuous number according to the present invention.

FIG. 14 is a diagram showing a frequency distribution of continuous numbers according to the present invention.

FIG. 15 is a diagram illustrating Doppler frequency detection according to the fourth embodiment of the present invention.

FIG. 16 is a diagram illustrating Doppler frequency detection according to the fourth embodiment of the present invention.

FIG. 17 is a diagram illustrating Doppler frequency detection according to the fourth embodiment of the present invention.

FIG. 18 is a diagram illustrating Doppler frequency detection according to the fourth embodiment of the present invention.

FIG. 19 is a diagram showing a step size switching criterion according to the present invention.

FIG. 20 is a configuration diagram of a step size determination unit of the transmission power control apparatus according to the fourth embodiment of the present invention.

FIG. 21 is a configuration diagram of a step size determination unit of the transmission power control apparatus according to the fourth embodiment of the present invention.

FIG. 22 is a configuration diagram of a step size determination unit of the transmission power control apparatus according to the fourth embodiment of the present invention.

FIG. 23 is a configuration diagram of a step size determination unit of the transmission power control apparatus according to the fourth embodiment of the present invention.

FIG. 24 is a block diagram showing a transmission power control device according to a fourth embodiment of the present invention.

FIG. 25 is a block diagram showing a transmission power control device according to a fifth embodiment of the present invention.

FIG. 26 is a diagram showing an operation of the transmission power control apparatus according to the fifth embodiment of the present invention.

FIG. 27 is a block diagram showing a transmission power control device according to a fifth embodiment of the present invention.

FIG. 28 is a block diagram showing a transmission power control device according to a fifth embodiment of the present invention.

FIG. 29 is a block diagram showing a conventional transmission power control device.

[Fig. 30] Fig. 30 is a diagram for describing time variation of base station reception power when there is no control delay in the conventional transmission power control device.

[Fig. 31] Fig. 31 is a diagram for describing time variation of base station reception power when the control delay in the conventional transmission power control device is 1T.

FIG. 32 is a diagram showing transmission power control error characteristics of a conventional transmission power control device.

[Fig. 33] Fig. 33 is a diagram for describing time variation of base station reception power when the control delay is 1 in the conventional transmission power control device.

[Explanation of symbols]

101 base station, 102 mobile station, 103 adder, 1
04 decision device, 105 amplifier, 106 adder, 107
Delay circuit, 108 adder, 109 amplifier, 110
Delay circuit, 111 TPC bit storage unit, 112 consecutive number / continuous number counting unit, 113 step size determining unit, 114 TPC bit storing unit, 115 consecutive number / continuous number counting unit, 116 step size determining unit, 117
Amplifier, 118 delay circuit, 119 control algorithm, 180 command generation unit, 181 correction unit, 183
Power setting unit, 184 amplifier, 190 transmission power control unit, 182 speed detecting unit, 192 speed detecting unit, 193
Power setting unit, 194 amplifier, 195 switch, 1
96 averaging unit, 301 comparator, 302 comparator, 3
03 comparator, 304 comparator, 305 AND gate, 306 NAND gate, 307 selector, 30
8 selectors, 309 OR gates, 310 NOR gates, 311 NOT gates, 312 NOT gates, 4
01 base station reception SIR, 402 base station reception SIR,
403 base station reception SIR, 404 base station reception SIR,
411 base station reception SIR, 412 base station reception SI
R, 413 base station reception SIR, 414 base station reception S
IR, 421 base station reception SIR, 422 base station reception SIR, 423 base station reception SIR, 424 base station reception SIR, 501 TPC bit, 502 TPC bit, 503 TPC bit, 504 TPC bit, 5
10 TPC bits, 511 TPC bits, 512
TPC bit, 513 TPC bit, 514 TPC
Bits, 520 TPC bits, 521 TPC bits,
522 TPC bits, 523 TPC bits, 524
TPC bit, 603 average.

Claims (7)

(57) [Claims] 1. A transmission power control apparatus for controlling transmission power of a transmitting station when transmitting data from a transmitting station to a receiving station by a code division multiple access (CDMA) method, wherein the receiving station is a receiving transmitting station. A command generation unit that generates a transmission power control command for controlling the transmission power of the transmission station based on the transmission power from the transmission station and transmits the transmission power control command to the transmission station, and the command generation unit controls the transmission power control command from the transmission station. Is a command generation unit that generates a transmission power control command based on the received transmission power from the transmission station and the transmission power control command already transmitted to the transmission station, wherein the command generation unit is The transmitting station transmits a certain transmission power control command to the receiving station, and then the receiving station changes the transmission power of the transmitting station based on the transmitting power control command. ,
If there is a delay time until the transmission power is input to the receiving station, based on the control content by the transmission power control command transmitted from the transmitting station to the receiving station during the delay time,
A delay circuit for correcting the transmission power control command generated from the received transmission power, wherein the correction unit inputs the transmission power control command, delays the transmission power control command by the delay time, and outputs the transmission power control command. And an amplifier that inputs the transmission power control command output from the delay circuit and generates and outputs the same increment as the increment of the transmission power that the reception unit inputs and generates the transmission power control command, and an output from the amplifier. And a transmission power control unit that receives the transmission power control command and controls the transmission power based on the transmission power control command. The power control unit stores a first step size and a second step size, which are units for increasing or decreasing the transmission power,
A transmission power control apparatus, which dynamically switches between a first step size and a second step size to control an increase / decrease in transmission power. 2. The transmission power control unit includes a speed detecting unit for detecting a moving speed of the transmitting station, and a first step size and a second step based on the moving speed of the transmitting station detected by the speed detecting unit. The transmission power control apparatus according to claim 1, further comprising a step size determination unit that selectively determines one of the sizes. Wherein said speed detecting section includes a storage section for storing the transmission power control commands, the number of stations of the accumulated transmission power control command and a count toss Ru counting unit, the step size determining section, 3. The transmission power control device according to claim 2, wherein one of the first step size and the second step size is selectively determined based on the number of consecutive transmission power control commands counted by the counting unit. Wherein said speed detecting section includes a storage section for storing the transmission power control commands, the consecutive number of the accumulated transmission power control command and a count toss Ru counting unit, the step size determining section, The transmission according to claim 2, wherein one of the first step size and the second step size is selectively determined based on the number of consecutive transmission power control commands counted by the counting section. Power control device. 5. A transmission power control device for controlling the transmission power of the transmitting station when data is transmitted from the transmitting station to the receiving station by a code division multiple access (CDMA) system, wherein the receiving station is the receiving transmitting station. A transmission power control command having a polarity for controlling the transmission power of the transmitting station based on the transmission power from the transmitting station, and transmitting to the transmitting station, the transmitting station receives the transmitting power control command. A transmission power control unit that controls the transmission power based on the transmission power control command, and the command generation unit is configured to transmit power based on the received transmission power from the transmission station and the transmission power control command already transmitted to the transmission station. In addition to generating the control command, the command generation unit calculates the difference between the transmission power from the transmission station and a predetermined reference power and outputs a power control error. If, as not the same polarity is continuously <br/> transmit power control commands when the value of the power control error to input the power control error and the past transmission power control command is within a predetermined range A transmission power control device comprising a control algorithm for outputting a transmission power control command. 6. The command generating unit, wherein the transmitting station transmits a certain transmission power control command to the receiving station, the receiving station changes the transmitting power of the transmitting station based on the transmitting power control command, and If there is a delay time before the transmission power is input to the receiving station, it is generated from the received transmission power based on the control contents by the transmission power control command sent from the transmitting station to the receiving station during the delay time. a correction unit for correcting the transmission power control command that, the correction unit, the slow enter the transmission power control commands
Output the transmission power control command with a delay of the total time.
Delay circuit and the transmission power control command output from the delay circuit.
Command, and the receiver enters the transmission power control command.
To generate the same increment of transmit power
The amplifier that outputs and the increment that is output from the amplifier are
And an adder for adding to the force control error.
The transmission power control device according to claim 5. 7. The command generation unit, which adds a difference between the transmission power from the transmission station and a predetermined reference power and outputs a power control error, and increases or decreases the transmission power of the transmission station from the power control error. A determining unit for determining and outputting a transmission power control command, wherein the correcting unit inputs the transmission power control command output from the determining unit and corrects the power control error. 6. The transmission power control device according to 6 .