JP2013247500A - Radio communication device and power control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication device and a power control method capable of reducing the load given to a communication partner even when inter-signal phase difference of a signal transmitted from plural antennas at the communication partner side is received in an inverted phase at a receiving station.SOLUTION: A phase difference calculation section 115 calculates a phase difference between transmission antenna signals at a receiving station (CDMA communication device 100) using CPICH transmitted from the respective antennas of a communication partner having plural transmission antennas. When the phase difference calculated by the phase difference calculation section 115 exceeds a predetermined first threshold value, a power control command determination section 117 determines that the phase difference between the signals is inverted and determines a power control command to an inverted value of the previously transmitted power control command.

Description

  The present invention relates to a radio communication apparatus and a power control method for controlling transmission power of a transmitting station from a receiving station so that the receiving station achieves desired reception quality.

  In recent years, mobile phones have become multifunctional, and not only voice calls but also videophones, the Internet, e-mails, digital cameras, etc., have been used for various purposes. Along with the increase in functionality, the provision of various services increases the capacity of content, and there is a demand for faster communication and lower communication charges in order to use them more comfortably. Against this background, W-CDMA (Wideband Code Division Multiple Access) communication systems have already been standardized in third generation mobile communication systems.

  In the W-CDMA communication system, a plurality of channels share the same frequency band and perform communication by assigning orthogonal spreading codes to each channel and distinguishing the channels.

  In an actual mobile communication environment, a received signal is subject to in-cell interference and other-cell interference due to delayed waves due to multipath fading or radio waves from other cells, and communication is adversely affected. Further, the amount of interference received by the received signal changes with time due to instantaneous fluctuations in received power due to multipath fading or changes in the number of users communicating simultaneously. As described above, under an environment that receives interference that varies with time, it is difficult to stably maintain a received signal at a desired quality in a mobile station (receiving station) connected to a base station (transmitting station).

  Therefore, in order to follow such instantaneous value fluctuations and changes in the number of interfering users due to multipath fading, the mobile station side assigns a SIR (Signal to Interference Ratio) of a DPCH (Dedicated Physical Channel) allocated to each mobile station. The transmission power control (TPC) controls the transmission power of the base station so that the measurement SIR of the mobile station approaches the target SIR by measuring the interference SNR) and comparing the measurement SIR with the target SIR. Is done. For example, when the measurement SIR is lower than the target SIR, the base station is requested to transmit power “UP” with a UL-TPC (Uplink-TPC) command mapped to the uplink DPCCH (Dedicated Physical Control Channel), and the measurement is performed. When the SIR is higher than the target SIR, the base station is requested to transmit power “DOWN”. As shown in FIG. 1, the mobile station generally measures the SIR using the pilot bits of the DPCH, and sets “UP” or “DOWN” in the UL-TPC of the UL slot after 1024 chips from the top of the DPCH. Transmit (see FIG. 2).

  Further, in recent years, with the increasing needs for high-speed data communication, the HSDPA (High Speed Downlink Packet Access) method has been standardized by 3GPP Release 5 as an enhancement of the W-CDMA communication method. In the HSDPA communication method, the mobile station receives high-speed data on the downlink shared channel of HS-PDSCH (High Speed Physical Downlink Shared Channel) and simultaneously transmits control information (DL-TPC symbol) related to uplink transmission on the downlink dedicated basis. Must be received on the channel. For this reason, although there is no need for data transmission on the downlink dedicated channel, one user occupies one spreading code, which is a radio resource, and a shortage of radio resources occurs.

  In order to solve this problem, F-DPCH (Fractional Downlink Physical Channel) has been standardized in 3GPP Release 6. The F-DPCH transmits only one control information symbol (DL-TPC symbol) and shares one spreading code with a plurality of users in a time division manner. The SIR is also measured for this F-DPCH, and transmission power control for the above-described base station is performed (see Patent Document 1). As shown in FIG. 3, since there are no pilot bits in the F-DPCH, generally, the SIR is measured using a DL-TPC symbol, and the UL slot of the UL slot 1024 chips after the head of the F-DPCH slot is measured. “UP” or “DOWN” is transmitted by TPC (see FIG. 4).

  On the other hand, when a base station transmits a bit sequence in STTD (Space Time Block Coding Based Transmit Antenna Diversity) mode using two transmission antennas, as shown in FIG. By STTD encoding the symbol pattern, the signal from the two antennas can be combined at the maximum ratio in the mobile station.

International Publication No. 2009/084091

  However, when transmitting F-DPCH in STTD mode, only 2 bits of DL-TPC are transmitted, so the STTD encoding described above cannot be performed, and the same transmission from two transmission antennas as shown in FIG. A bit sequence is transmitted. When the bit sequences transmitted from the two transmission antennas have opposite phases in the mobile station, DPCH and the like that are STTD encoded can separate the two signals, but the F-DPCH cannot be separated. When the F-DPCH bit sequences transmitted from the two transmission antennas have opposite phases in the mobile station, the two signals cancel each other, and the reception level is significantly reduced.

  In such a case, with the power control method described in Patent Document 1 described above, the mobile station cannot determine whether the reception level is decreased due to fading or the reception level is decreased due to the reverse phase. For this reason, even when the base station transmits F-DPCH with sufficiently large transmission power, if the phase at the mobile station is opposite, the mobile station can only determine that the reception level is low. Therefore, the base station is requested to increase the transmission power (UL-TPC command = “UP”), and there is a problem that an unnecessary load is applied to the base station.

  An object of the present invention is to reduce the load applied to a communication partner even when the inter-signal phase difference of signals transmitted from a plurality of antennas on the communication partner side is received in an opposite phase at the receiving station. A communication device and a power control method are provided.

  The wireless communication device of the present invention uses a receiving means for receiving a signal transmitted from each antenna of a communication partner having a plurality of antennas, and a phase difference between antenna signals in the own device using the received signal. When the phase difference calculation means to calculate and the calculated phase difference exceeds a predetermined first threshold value, a power control command is determined that averages the transmission power of the communication partner to be constant, and the phase difference is A power control command determining unit that determines a power control command according to reception quality when the first threshold value or less is employed.

  The power control method according to the present invention includes a reception step of receiving a signal transmitted from each antenna of a communication partner having a plurality of antennas, and a phase difference between antenna signals in the own device using the received signal. A phase difference calculating step to calculate, and when the calculated phase difference exceeds a predetermined first threshold, determine a power control command that averages the transmission power of the communication partner to be constant, and the phase difference is A power control command determining step for determining a power control command according to the reception quality when the first threshold value or less.

  According to the present invention, even when the phase difference between signals of signals transmitted from a plurality of antennas on the communication partner side is received in an opposite phase at the receiving station, the load applied to the communication partner is reduced. Can do.

Diagram showing DPCH slot format The figure which shows the transmission power control timing of DPCH The figure which shows F-DPCH slot format The figure which shows the transmission power control timing of F-DPCH The figure which shows a mode that DPTD is STTD-encoded The figure which shows a mode that FTDPCH is STTD encoded 1 is a block diagram showing a schematic configuration of a CDMA communication apparatus according to Embodiment 1 of the present invention. The block diagram which shows the internal structure of the demodulation part shown in FIG. The flowchart which shows the process sequence of the power control command determination part shown in FIG. The figure which shows the example of transmission of a power control command The figure which shows the relationship between the electric power and phase difference after composition of two signals The flowchart which shows the process sequence of the power control command determination part which concerns on Embodiment 2 of this invention. The figure which uses for description of the reason which compares F-DPCH SIR with a 2nd threshold value The block diagram which shows the internal structure of the demodulation part which concerns on Embodiment 3 of this invention. The flowchart which shows the process sequence of the phase difference state determination part shown in FIG. The figure used for explanation of the reason for comparing the phase difference with the third threshold value The block diagram which shows the internal structure of the demodulation part which concerns on Embodiment 4 of this invention. The flowchart which shows the process sequence of the electric power control command determination part shown in FIG. Diagram for explaining the reason for comparing CPICH SIR with the fourth threshold

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, in the embodiment, components having the same function are denoted by the same reference numerals, and redundant description is omitted.

(Embodiment 1)
FIG. 7 is a block diagram showing a schematic configuration of CDMA communication apparatus 100 according to Embodiment 1 of the present invention. Hereinafter, a schematic configuration of the CDMA communication apparatus 100 will be described with reference to FIG.

  The antenna 101 transmits and receives a CDMA signal, and the receiving unit 102 performs filtering and AD conversion on the CDMA signal received via the antenna 101 to convert the signal into a baseband digital signal, and outputs the baseband digital signal to the demodulating unit 103. Demodulation section 103 performs despreading and demodulation on the baseband digital signal output from reception section 102, outputs demodulated control information (power control command) to modulation section 106, and outputs the demodulated signal to decoding section 104. To do. Decoding section 104 decodes the signal output from demodulation section 103 and outputs received data.

  Encoding section 105 encodes transmission data and outputs the encoded data to modulation section 106. Modulation section 106 modulates the encoded data output from encoding section 105 and the control information output from demodulation section 103, spreads the modulated signal, and outputs the result to transmission section 107. The transmission unit 107 performs filtering and DA conversion on the signal output from the modulation unit 106, converts the signal into an analog signal, and transmits the analog signal.

  FIG. 8 is a block diagram showing an internal configuration of the demodulator 103 shown in FIG. Hereinafter, the internal configuration of the demodulation unit 103 will be described with reference to FIG.

  The F-DPCH despreading unit 110 despreads the F-DPCH out of the digital signal A / D converted by the receiving unit 102 and outputs the despread F-DPCH to the rake combining unit 112.

  CPICH despreading section 111 despreads CPICH out of the digital signal A / D converted by receiving section 102 and outputs the despread F-DPCH to rake combining section 112.

  The rake combining unit 112 rake-combines the F-DPCH output from the F-DPCH despreading unit 110 and the CPICH output from the CPICH despreading unit 111, respectively, and the rake combined CPICH symbol is an interference power calculation unit 113. The R-combined F-DPCH symbol is output to the F-DPCH SIR measurement unit 114.

  Interference power calculation section 113 calculates interference power from the CPICH symbol output from rake combining section 112, and outputs the calculated interference power to F-DPCH SIR measurement section 114. Here, for example, the interference power can be obtained by calculating the dispersion value of the CPICH symbol after rake combining.

  F-DPCH SIR measurement section 114 measures the signal power of the F-DPCH symbol output from rake combining section 112. The signal power can be obtained, for example, by squaring an F-DPCH symbol averaged over one slot interval. The F-DPCH SIR measurement unit 114 calculates a ratio between the measured signal power of the F-DPCH and the interference power output from the interference power calculation unit 113 as F-DPCH SIR. The calculated F-DPCH SIR is output to the power control command determination unit 117.

The phase difference calculation unit 115 uses the CPICH output from the CPICH despreading unit 111 to determine the position in the reception station (CDMA communication apparatus 100) between transmission antenna signals transmitted from the plurality of antennas of the transmission station (communication partner side). The phase difference is calculated, and the calculated phase difference is output to the power control command determination unit 117. Note that the phase difference θ can be calculated by the following equation (1), for example.

Here, θ is a phase difference (where 0 ≦ θ ≦ π), and CP_SYM _{i, I} and CP_SYM _{i, Q} are CPICH symbols transmitted from the transmitting station transmitting antenna i (i = 1, 2), respectively. Component, Q component. Arctan () is an inverse function of the trigonometric function tangent and returns a value of −π to π. In order to reduce the influence of interference, for example, a value averaged over one slot period may be used for the CPICH symbol.

  A target SIR setting unit 116 holds in advance a correspondence table between target quality and target SIR necessary to achieve the target quality, and sets the target quality transmitted from UTRAN (UMTS Terrestrial Radio Access Network) to the corresponding target. The data is converted into SIR and output to the power control command determination unit 117.

  The power control command determination unit 117 sets the phase difference output from the phase difference calculation unit 115, the F-DPCH SIR output from the F-DPCH SIR measurement unit 114, and the target SIR output from the target SIR setting unit 116. Based on this, a power control command to the communication partner is determined.

  Next, the processing procedure of the power control command determination unit 117 described above will be described with reference to FIG. In step (hereinafter abbreviated as “ST”) 301, the phase difference calculated by the phase difference calculation unit 115 is compared with a predetermined first threshold value. Since the phase difference is in the opposite phase, it is determined that there is no need to request the transmission station to increase transmission power, and the process proceeds to ST302. On the other hand, if the phase difference is equal to or smaller than the first threshold (NO), it is determined that the phase is not opposite, and the process proceeds to ST303.

  In ST302, the power control command is determined as an inverted value of the power control command transmitted last time. For example, as shown in FIG. 10, when “UP” was transmitted last time, “DOWN” is determined, and when “DOWN” is transmitted last time, “UP” is determined.

  In ST303, the measurement SIR is compared with the target SIR. If the measurement SIR exceeds the target SIR (YES), the process proceeds to ST304, and if the measurement SIR is equal to or less than the target SIR (NO), the process proceeds to ST305.

  In ST304, a power control command “DOWN” that is a request to lower the transmission power to the transmitting station is determined, and in ST305, a power control command “UP” that is a request to increase the transmission power to the transmitting station is determined.

  In ST302, the power control command is “UP, UP, DOWN, DOWN,...” Or “UP, DOWN, DOWN, UP,. You may decide. In addition, when a command (for example, “KEEP”) that maintains transmission power is defined for the transmitting station, the power control command may be “KEEP”.

  Further, as a first threshold setting method for determining whether or not the phase is opposite in ST301, for example, as shown in FIG. 11, the relationship between the power (power ratio) after the combination of two signals and the phase difference is shown. It is good also as 150 degrees from which electric power becomes low 10 dB or more compared with the synthesis | combination in the same phase (phase difference 0 degree) with the largest electric power later.

  Thus, according to Embodiment 1, when F-DPCH is transmitted from a plurality of transmission antennas on the communication partner side in the transmission diversity mode, the phase difference between the transmission antenna signals at the receiving station is reversed. Therefore, by setting the power control command transmitted to the communication partner to the inverted value of the previous command, it is possible to reduce the load applied to the communication partner without requesting the communication partner to increase unnecessary power. Thereby, interference with other communication devices can also be reduced and the throughput of the entire system can be improved.

(Embodiment 2)
The configuration of the CDMA communication apparatus according to Embodiment 2 of the present invention is the same as that shown in FIGS. 7 and 8 of Embodiment 1, and will be described with appropriate reference to FIGS.

  The processing procedure of the power control command determination unit 117 according to Embodiment 2 of the present invention will be described with reference to FIG. However, in FIG. 12, the same processes as those in FIG. 9 are denoted by the same reference numerals as those in FIG.

  In ST301, when the phase difference exceeds the first threshold value (YES), the process proceeds to ST310, and in ST310, the F-DPCH SIR calculated by the F-DPCH SIR measurement unit 114 is compared with a predetermined second threshold value. . When F-DPCH SIR is smaller than the second threshold (YES), the power control command is determined as an inverted value of the power control command transmitted last time (ST302). On the other hand, when the F-DPCH SIR is equal to or greater than the second threshold (NO), the power control command is determined according to the reception quality (SIR) (ST303 to ST305).

  Note that the second threshold may be set to 0 dB based on the noise power level, for example.

  Here, the reason why F-DPCH SIR is compared with the second threshold in ST310 will be described with reference to FIG. Even when the F-DPCH is transmitted in the transmission diversity mode and the phase difference between the transmission antenna signals at the receiving station is opposite, the F-DPCH SIR is as shown in section 1 of FIG. When it is lower than the second threshold, the signal amplitudes of the two transmission antennas 1 and 2 are approximately the same (see FIG. 13B), and it is expected that the signal power after the synthesis of the two signals is very small. The In such a case (F-DPCH SIR <second threshold), it is not possible to expect an improvement in reception performance even if the transmission station is requested to increase the power. Therefore, a power control command is transmitted alternately, for example, UP and DOWN. (See FIG. 13 (c)).

  On the other hand, as shown in section 2 of FIG. 13A, there is a signal amplitude difference between the transmitting antennas 1 and 2 when the phase difference is opposite and the F-DPCH SIR is greater than or equal to the second threshold. Is expected (see FIG. 13D). In such a case (F-DPCH SIR ≧ second threshold), power control (see FIG. 13 (e)) corresponding to the reception quality shown in ST303 to ST305 is performed according to the target quality set by UTRAN. Can be received.

  Thus, according to the second embodiment, even if the phase difference between the transmitting antenna signals at the receiving station is an opposite phase, if the F-DPCH SIR is equal to or larger than the second threshold value, the reception quality depends on the reception quality. By transmitting the power control command, it is possible to receive with the desired target quality.

(Embodiment 3)
The configuration of the CDMA communication apparatus according to Embodiment 3 of the present invention is the same as that shown in FIG. 7 of Embodiment 1, and will be described with appropriate reference to FIG.

  FIG. 14 is a block diagram showing an internal configuration of demodulation section 103 according to Embodiment 3 of the present invention. FIG. 14 differs from FIG. 8 in that a phase difference state determination unit 120 is added and the power control command determination unit 117 is changed to a power control command determination unit 121.

  The phase difference state determination unit 120 averages the phase difference output from the phase difference calculation unit 115 in a certain section (for example, 15 slots), and based on the comparison result between the averaged phase difference and a predetermined third threshold value, The phase difference state is determined as “reverse phase” or “normal”. The determination result is output to the power control command determination unit 121.

  The power control command determination unit 121 includes a phase difference state output from the phase difference state determination unit 120, an F-DPCH SIR output from the F-DPCH SIR measurement unit 114, and a target output from the target SIR setting unit 116. Based on the SIR, a power control command to the communication partner is determined. The specific process of the power control command determination unit 121 is obtained by replacing the process using the phase difference in the power control command determination unit 117 of Embodiment 1 with the process using the phase difference state.

  Next, a processing procedure of the above-described phase difference state determination unit 120 will be described with reference to FIG. In ST320, it is determined whether or not 15 slots have elapsed. If 15 slots have elapsed (YES), the process proceeds to ST322, and if 15 slots have not elapsed (NO), the process proceeds to ST321. To do.

  In ST321, the phase differences calculated by phase difference calculation section 115 are cumulatively added, the slot counter is incremented by 1, and the process returns to ST320.

  In ST322, the phase differences cumulatively added for 15 slots are averaged. Also, the slot counter is initialized to zero.

  In ST323, the phase difference averaged in ST322 is compared with the third threshold value. When the third threshold value is exceeded (YES), the process proceeds to ST324, and when it is equal to or less than the third threshold value (NO), the process proceeds to ST325. .

  In ST324, the phase difference state is determined as “reverse phase”, and in ST325, the phase difference state is determined as “normal”. The initial value of the slot counter may be 0, and the initial state of the phase difference may be “normal”.

  Here, the reason why the phase difference is compared with the third threshold in ST323 will be described with reference to FIG. The phase difference state determination unit 120 determines that the phase difference state is “normal” when the phase difference is small as shown in section 1 of FIG. 16, and the power control command determination unit 121 determines the measurement SIR and the target SIR. Power control is performed according to the reception quality to be compared.

  Also, as shown in section 2 in FIG. 16, when the phase difference temporarily becomes an antiphase, or when the phase difference is temporarily calculated as an antiphase due to the influence of calculation accuracy, the phase difference is averaged for 15 slot sections. By doing so, these effects can be reduced. As a result, since the averaged phase difference is less than the third threshold value, the phase difference state determination unit 120 determines that the phase difference state is “normal”, and also in section 2, the power control command determination unit 121 determines that the measurement SIR Power control is performed according to the reception quality for comparison with the target SIR. Thus, by measuring the phase difference state over a longer time, power control according to the target quality can be performed.

  Furthermore, as shown in section 3 of FIG. 16, when the phase difference is a fixed section reverse phase, the phase difference averaged over the fixed section exceeds the third threshold value, so the phase difference state determination unit 120 displays the phase difference state. Judged as “reverse phase”. In such a case, the power control command determination unit 121 determines the inverted value of the previous command (for example, alternately changed like UP, DOWN, UP, DOWN) as the power control command.

  As described above, according to the third embodiment, when the phase difference in a certain section is averaged and the averaged phase difference is less than the third threshold, by transmitting a power control command according to the reception quality, Reception can be performed with a desired target quality.

  In the present embodiment, the average fixed interval is 15 slots, but the present invention is not limited to 15 slots, and may be 30 slots or 45 slots. In addition, when the moving speed of the receiving station can be monitored, the average interval may be adaptively changed according to the moving speed.

  In the present embodiment, the power control command is determined as the inverted value of the previous command when the phase difference state is “reverse phase”. However, the present invention is not limited to this, and “UP , UP, DOWN, DOWN,..., Or “UP, DOWN, DOWN, UP,...”, Etc., may be determined such that the transmission power of the transmitting station is constant on average. Further, when a command for maintaining transmission power (KEEP) is defined for the transmitting station, the power control command may be “KEEP”.

  In the present embodiment, after the phase difference state determination unit 120 determines that the phase difference state is “reverse phase”, the F-DPCH SIR is set to the second threshold value in the power control command determination unit 117 described in the second embodiment. It may be determined whether it is smaller than (ST310). If F-DPCH SIR is smaller than the second threshold as a result of this determination, the power control command is determined as the inverted value of the previously transmitted power control command (ST302), and F-DPCH SIR is greater than or equal to the second threshold. Determines a power control command according to reception quality (SIR) (ST303 to ST305).

(Embodiment 4)
The configuration of the CDMA communication apparatus according to Embodiment 4 of the present invention is the same as that shown in FIG. 7 of Embodiment 1, and will be described with appropriate reference to FIG.

  FIG. 17 is a block diagram showing an internal configuration of demodulation section 103 according to Embodiment 4 of the present invention. FIG. 17 differs from FIG. 8 in that a CPICH SIR measurement unit 130 is added and the power control command determination unit 117 is changed to a power control command determination unit 131.

  CPICH SIR measurement section 130 measures the signal power of the CPICH symbol output from rake combining section 112. The signal power can be obtained, for example, by squaring a CPICH symbol averaged over one slot section. The CPICH SIR measurement unit 130 calculates the ratio between the measured signal power of CPICH and the interference power output from the interference power calculation unit 113 as the CPICH SIR. The calculated CPICH SIR is output to the power control command determination unit 131.

  The power control command determination unit 131 includes a phase difference output from the phase difference calculation unit 115, an F-DPCH SIR output from the F-DPCH SIR measurement unit 114, a CPICH SIR output from the CPICH SIR measurement unit 130, and Based on the target SIR output from the target SIR setting unit 116, a power control command to the communication partner is determined.

  Next, the processing procedure of the power control command determination unit 131 will be described with reference to FIG. However, in FIG. 18, the same processes as those in FIG. 12 are denoted by the same reference numerals as those in FIG.

  In ST310, when the F-DPCH SIR is smaller than the second threshold, the process proceeds to ST330, and in ST330, the CPICH SIR calculated by the CPICH SIR measurement unit 130 is compared with a predetermined fourth threshold. When CPICH SIR is equal to or lower than the fourth threshold (NO), a power control command is determined according to the reception quality (ST303 to ST305). On the other hand, when CPICH SIR is larger than the fourth threshold (YES), the power control command is determined as the inverted value of the power control command transmitted last time (ST302).

  For example, the fourth threshold value may be 0 dB based on the noise power level.

  Here, the reason why the CPICH SIR is compared with the fourth threshold in ST330 will be described with reference to FIG.

  As shown in section 1 of FIG. 19, when the phase difference is opposite, F-DPCH SIR is smaller than the second threshold value, and CPICH SIR is smaller than the fourth threshold value, the reception quality of the receiving station is considered bad. Therefore, the power control command determination unit 131 performs power control according to the reception quality for comparing the measured SIR and the target SIR.

  Also, as shown in section 2 of FIG. 19, when the phase difference is opposite phase, the F-DPCH SIR is smaller than the second threshold, and the CPICH SIR is larger than the fourth threshold, the reception environment of the receiving station is compared. Therefore, power control commands are transmitted alternately UP and DOWN.

  In this way, by comparing the CPICH SIR with the fourth threshold value, for example, when the reception environment of the reception station is bad (section 1), for example, the reception station exists in the shadow of the building, the reception station becomes the transmission station. Since an increase in transmission power can be requested, high-quality reception can be realized immediately and reception performance can be improved when the reception environment is improved (section 2), such as when the receiving station comes out of the shadow of the building.

  As described above, according to the fourth embodiment, by comparing the CPICH SIR and the fourth threshold value, when the reception environment of the receiving station is drastically improved, high-quality reception can be realized immediately, and reception performance can be achieved. Can be improved.

  In the present embodiment, the phase difference state determination unit 120 shown in the third embodiment may be combined. In this case, ST301 for comparing the phase difference with the first threshold is replaced with a process for determining the phase difference state.

  In each of the above embodiments, the SIR has been described as an example of the index indicating the reception quality. However, the present invention is not limited to this, and other indexes such as SINR (Signal to Interference and Noise Ratio) and the received electric field strength are used. May be used.

  The radio communication apparatus and the power control method according to the present invention can be applied to, for example, a radio communication system that controls transmission power of a transmission station according to a reception environment of the reception station.

DESCRIPTION OF SYMBOLS 101 Antenna 102 Receiving part 103 Demodulating part 104 Decoding part 105 Coding part 106 Modulating part 107 Transmitting part 110 F-DPCH despreading part 111 CPICH despreading part 112 Rake combining part 113 Interference power calculating part 114 F-DPCH SIR measuring part 115 Phase difference calculation unit 116 Target SIR measurement unit 117, 121, 131 Power control command determination unit 120 Phase difference state determination unit 130 CPICH SIR measurement unit

Claims (8)

Receiving means for receiving a signal transmitted from each antenna of a communication partner having a plurality of antennas;
Using the received signal, a phase difference calculating means for calculating a phase difference between antenna signals in the device itself;
When the calculated phase difference exceeds a predetermined first threshold value, a power control command is determined that averages the transmission power of the communication partner to be constant, and the phase difference is equal to or less than the first threshold value. A power control command determination means for determining a power control command according to the reception quality;
A wireless communication apparatus comprising: A phase difference state determining unit that averages the phase difference in a fixed section and determines the state of the phase difference based on the averaged phase difference,
When the averaged phase difference exceeds a predetermined third threshold, the power control command determining means determines a power control command that averages the transmission power of the communication partner to be constant, and the averaged phase difference Is less than or equal to the third threshold, a power control command is determined according to reception quality.
The wireless communication apparatus according to claim 1. The phase difference state determination means changes the fixed section according to the moving speed of the own device,
The wireless communication apparatus according to claim 2. An individual channel reception quality calculating means for calculating the reception quality of the individual channel;
The power control command determination means determines a power control command corresponding to the reception quality when the phase difference exceeds the first threshold and the reception quality of the dedicated channel is equal to or higher than a predetermined second threshold. If the reception quality of the dedicated channel is less than the second threshold, determine a power control command that averages the transmission power of the communication partner to be constant.
The wireless communication apparatus according to claim 1. A common channel reception quality calculating means for calculating the reception quality of the common channel;
When the reception quality of the dedicated channel is less than the second threshold value and the reception quality of the common channel exceeds a predetermined fourth threshold value, the power control command determination unit determines that the transmission power of the communication partner is an average. A power control command that is constant, and when the reception quality of the common channel is less than or equal to the fourth threshold, determine a power control command according to the reception quality;
The wireless communication apparatus according to claim 4. The power control command determining means determines a power control command for maintaining the transmission power of the communication partner when the phase difference exceeds the first threshold.
The wireless communication apparatus according to claim 1. The power control command determining means determines the inverted value of the power control command determined last time as the current power control command when the phase difference exceeds the first threshold;
The wireless communication apparatus according to claim 1. A receiving step of receiving a signal transmitted from each antenna of a communication partner having a plurality of antennas;
Using the received signal, a phase difference calculating step of calculating a phase difference between antenna signals in the device itself;
When the calculated phase difference exceeds a predetermined first threshold value, a power control command is determined that averages the transmission power of the communication partner to be constant, and the phase difference is equal to or less than the first threshold value. A power control command determination step for determining a power control command according to the reception quality;
A power control method comprising:

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