JP2008167031A - Radio communications equipment and radio communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein power control cannot make it track high-speed fading fluctuations because there is delay by demodulation and detection of power control information. <P>SOLUTION: This radio communications equipment (100) has a reception part (110) for receiving a signal transmitted from the opposite side radio communications equipment; a transmission part (180) for transmitting a signal to the opposite side radio communications equipment; a power control information generating part (140) for generating information about power control to be instructed, to the opposite side radio communications equipment, on the basis of the signal received from the opposite-side radio communications equipment; a moving state information acquisition part (150) for acquiring moving state information showing a relative moving state between the opposite side radio communications equipment and own equipment; and a control part (160) for controlling the transmission part so as to transmit information about power control as a signal that can read the information, on the basis of a correlation of a received signal, according to the moving state information acquired by the moving state information acquiring part, by making transmission to the opposite party by radio, or controlling the transmission part so as to transmit the information about power control, as a signal that requires demodulation to the opposite-side radio communications equipment. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus and a wireless communication method.

In the current iBurst (registered trademark) protocol, for example, link adaptation and transmission power control are performed in order to perform communication adapted to the radio wave propagation environment (see, for example, Patent Document 1). On the protocol, transmission power control and link adaptation have a control delay of 2 frames or more. For this reason, in the current system, information two or more frames before is used as control information used in performing transmission power control.
JP-T 9-510844

  In the conventional technology, in order to cope with a radio wave propagation environment that changes momentarily as the terminal moves, optimal control is performed by the transmission power control and link adaptation described above to improve throughput and stabilize the connection state. Make an effort. For example, in the case of a terminal that moves at a speed of 3 kmph (assuming that the frequency band is 2.57 GHz), it is an index of the frequency at which the radio wave propagation path changes suddenly and is an index that indicates the movement state (speed) of the terminal. If the maximum Doppler frequency is about 7.1 Hz and one frame is 5 msec, there is a high possibility that the phase and amplitude will fluctuate once in about 30 frames. However, the level down due to fading does not always occur in this cycle. Therefore, it is unlikely that the fading situation has fluctuated greatly between several frames (for example, between adjacent or several frames apart). Therefore, the reliability is high even if the control using the control information calculated from the radio wave propagation environment “2 frames before” is performed on the “current frame” as in the current system.

  However, this effort may not be rewarded if the speed of movement of the terminal is above a certain level. For example, when the terminal moving speed is about 50 kmph, the maximum Doppler frequency is 125 Hz. In this case, a sudden change occurs in the phase and amplitude once every about 8 msec. Therefore, in the case of a terminal (user) moving at about 50 kmph, the reception level (that is, power) of “a frame (m)” may be significantly different from the reception level of “the next frame (m + 1)”. There is a high possibility that it will not serve as a reference for the radio wave propagation environment during transmission. It is highly likely that controlling the transmission power based on the previous power control information for two frames will not make sense.

  The link adaptation may be controlled so as to obtain a stable throughput by performing control based on an average level so as to absorb some variation even when there is some variation. However, such a control method is based on the premise that the necessary power is sufficiently supplied on the power control side. In power control, power control is performed by generating power control information to be instructed to the counterpart terminal using the SINR (signal-to-interference and noise ratio) of “immediate (current) frame”. It seems effective to perform power control instantaneously and to perform adaptive modulation based on an average ability value.

  The movement speed of the terminal varies depending on the movement status (stationary state, walking, car, train, etc.) of the person carrying the terminal, and control that can be adapted to the movement status (radio wave propagation environment) of all terminals (people) is desirable. Therefore, it is necessary to realize a quick control of a reaction with as little delay as possible. The minimum delay is power control with one frame delay. By shortening the delay time from the current delay amount, it is possible to prevent waste of power, reduce the interference power to other users (terminals), and ultimately improve the throughput of the entire communication system. It is possible. In the current wireless communication system, power control information is transmitted as a signal that needs to be demodulated (RMU message, UM message). Therefore, a delay for demodulating and reading the power control information occurs for "about 2 frames". ing. With such a two-frame delay, as described above, transmission power control effective for communication with a terminal moving at high speed has not been achieved. For this reason, there has been a problem of performing unnecessary power radiation or transmitting a signal causing a frame error.

  As described above, when at least one terminal is moving at high speed in a wireless communication system, the desired signal power fluctuates frequently due to fading. However, in the current system, power control information is transmitted as a signal (message) that needs to be demodulated, so there is a delay due to demodulation and detection (reading) of the power control information, and it follows high-speed fading fluctuations. There was a problem that I could not.

  An object of the present invention is to provide a technique (apparatus and method) for performing optimal power control in accordance with a movement state (radio wave propagation environment) and a desired signal power fluctuation period when communicating with a radio communication apparatus with a high movement speed. ).

In order to solve the above-described problems, the wireless communication device (base station device, wireless communication terminal, etc.) according to the first invention
A receiving unit for receiving a signal transmitted from the counterpart wireless communication device;
(With a detector that detects the received signal)
A transmission unit for transmitting a signal to the counterpart wireless communication device;
A power control information generating unit that generates information on power control to be instructed to the counterpart wireless communication device based on a signal received from the counterpart wireless communication device;
A movement state information acquisition unit (for example, based on a frequency and a reference frequency of a signal received from the partner wireless communication apparatus, which acquires movement state information indicating a relative movement state between the partner wireless communication apparatus and the own apparatus, Calculating the maximum Doppler frequency that represents the relative movement state between devices, and calculating the relative movement speed from the calculated maximum Doppler frequency, etc.),
In accordance with the movement state information acquired by the movement state information acquisition unit, information on the power control generated by the power control information generation unit is received signal (by referring to the correlation table without demodulating). Is transmitted to the counterpart wireless communication apparatus as a signal that can read the information based on the correlation (for example, information stored in the FACCH message) or a signal that requires demodulation (information stored in the UM message). A control unit for controlling the transmission unit,
It is characterized by having.
The wireless communication device includes a spatial division multiple access (SDMA) base station device using an adaptive array antenna, or a spatial division multiple access (SDMA) wireless communication device and It is preferable to do.

A wireless communication apparatus according to the second invention is
The movement state information is a relative movement speed between the counterpart wireless communication device and the own device,
The control unit, when the relative movement speed exceeds a predetermined threshold,
Controlling the transmission unit to transmit the information related to the power control as a signal from which the information can be read based on the correlation of the received signal to the counterpart wireless communication device;
It is characterized by that.

According to a third aspect of the present invention, there is provided a wireless communication device.
When the relative moving speed is equal to or less than the predetermined threshold,
The transmission unit is configured to transmit at least information relating to link adaptation to be transmitted to the counterpart communication device to the counterpart radio communication device as a signal from which the information can be read based on a correlation of received signals. Control
And, the transmitter is controlled so that the information related to the power control is transmitted to the counterpart wireless communication device as a signal that requires demodulation.
It is characterized by that.

As described above, the solution of the present invention has been described as an apparatus. However, the present invention can be realized as a method, a program, and a storage medium that stores the program substantially corresponding to these, and the scope of the present invention. It should be understood that these are also included.
For example, the wireless communication method according to the fourth aspect of the present invention that realizes the present invention is as follows:
A wireless communication method for performing wireless communication between a first wireless communication device and a second wireless communication device,
The first wireless communication device should instruct the second wireless communication device based on a signal received from the second wireless communication device (using arithmetic means (a processor such as a CPU or DSP)) A power control information generation step for generating information on power control;
A movement state information acquisition step in which the first wireless communication apparatus acquires movement state information indicating a relative movement state between the second wireless communication apparatus and the first wireless communication apparatus (for example, the counterpart side Based on the frequency of the signal received from the wireless communication device and the reference frequency, a calculation means for calculating the maximum Doppler frequency representing the relative movement state between the devices, etc.),
By referring to the correlation table (without demodulating) the information related to the generated power control according to the movement state information acquired by the movement state information acquisition step, the first wireless communication device ) A control step of transmitting to the second wireless communication device as a signal that can read the information based on the correlation of the received signal (for example, information stored in the FACCH message) or a signal that requires demodulation;
It is characterized by including.

A wireless communication method according to a fifth invention is
Based on the correlation of the received signal, the second wireless communication apparatus receives the signal including the information related to the power control received from the first wireless communication apparatus (by referring to the correlation table without demodulating). Based on the information related to the power control thus read, the transmission power of the own device is controlled (for the next frame, for example, by adjusting the variable attenuator to the slot corresponding to the second wireless communication device). Transmitting to the first wireless communication device,
Is further included.

As described above, the present invention can be configured to perform control based on “movement state information”, but is configured to perform control based on “desired signal power fluctuation period” estimated based on movement state information, a received signal, and the like. It is also possible to take.
For example, a wireless communication apparatus according to a sixth invention based on a desired signal power fluctuation period is as follows:
A receiving unit for receiving a signal transmitted from the counterpart wireless communication device;
A transmission unit for transmitting a signal to the counterpart wireless communication device;
A power control information generating unit that generates information on power control to be instructed to the counterpart wireless communication device based on a signal received from the counterpart wireless communication device;
Based on a signal received from the counterparty wireless communication device, a desired signal received power fluctuation period estimation unit that estimates a desired signal power fluctuation period;
Reading the information on the power control generated by the power control information generation unit based on the correlation of the received signal according to the desired signal power fluctuation cycle estimated by the desired signal power fluctuation cycle estimation unit. A control unit that controls the transmission unit to transmit to the counterpart wireless communication device as a signal that can be transmitted or a signal that requires demodulation;
It is characterized by having.

According to a seventh aspect of the present invention, there is provided a wireless communication method.
In a wireless communication method for performing wireless communication between a first wireless communication device and a second wireless communication device,
A power control information generating step for generating information on power control to be instructed to the second wireless communication device based on a signal received by the first wireless communication device from the second wireless communication device;
A desired signal power fluctuation period estimating step in which the first wireless communication apparatus estimates a desired signal power fluctuation period based on a signal received from the second wireless communication apparatus;
The first wireless communication apparatus determines the generated information related to the power control based on the correlation of the received signal according to the desired signal power fluctuation period estimated in the desired signal power fluctuation period estimation step. A control step of transmitting to the second wireless communication device as a signal that can be read or a signal that requires demodulation;
It is characterized by including.

  Advantageous Effects of Invention According to the present invention, it is possible to improve the power path follow-up performance of power control of a terminal moving at high speed (and a base station communicating with a terminal moving at high speed), thereby improving the total throughput. It becomes possible. As a result, when communicating with a “terminal with a fast moving speed” that cannot be tracked with power control in the prior art, it follows the movement status (radio wave propagation environment) and the desired signal power fluctuation cycle. Optimal power control can be performed, and more stable communication quality can be provided to the user.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a hardware configuration diagram of a base station according to the present invention. As shown in the figure, the base station 10 includes an adaptive array antenna ANT, an RF processing unit 11 that processes a received signal, and a signal processing unit 12 that processes a signal processed by the RF processing unit 11. The signal processing unit 12 includes a DSP (digital signal processor) 1-3, and the DSP 1-3 performs processing of the time slots 1-3 separately. In this configuration, it is assumed that the DSPs 1-3 operate independently for each carrier frequency. Although FIG. 1 shows a base station (apparatus), the terminal apparatus similarly performs signal processing for each time slot using another arithmetic device (DSP or the like). Each DSP performs processing in accordance with the transmission / reception processing time of the corresponding time slot. The transmission / reception processing needs to be within one frame (5 msec) in total. It is assumed that the system is operated using the base station and the terminal device having such a configuration.

  Prior to the description of the present invention, a conventional power control technique will be described in order to help understand the configuration and principle of the present invention. Conventionally, transmission power control and link adaptation are performed using the following method.

FIG. 7 shows a sequence diagram for explaining a message (signal) usage mode (RMU (Radio Link Control Message Unit) header, UM (Unaknowledge Mode) message) regarding power control in the prior art. In addition, although a base station will be described as an example, the configuration and processing on the terminal side are the same in principle.
<Base station power control>
RMU header (1 bit in the header): Power control information PCI (power increase or decrease) is stored.
UM message (5-6 bits in header): Power control information PCI (current power value information) is stored.
As described above, in this specification, power control information is referred to as PCI (Power Control Information).

The link adaptation is transmitted by FACCH (Fast Associated Control Channel) as described below.
<Base station link adaptation (adaptive modulation control)>
FACCH (16 bits are used, but the actual information amount is 4 bits): Stores information for link adaptation (downlink modulation class, (uplink) recommended modulation class, (uplink) current modulation class, Including the power range that can be increased in the downlink).

  Here, the difference between the UM message and the RMU header and the FACCH message will be described. The contents of the RMU header and UM message can only be read (determined) after detection and demodulation processing, whereas the FACCH does not undergo demodulation processing after detection (that is, if timing is detected). In addition, the data content stored therein can be read (determined). FACCH messages can be read (acquired) by detecting highly correlated data from a fixed pattern by referring to a table that defines the correlation, but processing requires about 1.5 frames. Therefore, control information based on data read in a certain frame [m] cannot be reflected in transmission of the next frame [m + 1].

<Transmission power control: UM message usage>
The processing base station BS on the base station side obtains SINR (or DSSI) information based on the received signal after performing the detection processing of the uplink signal UL1 of the frame k which is the current frame transmitted from the terminal UT. Based on the obtained SINR information, the power control information PCI to be instructed to the terminal is stored in the RMU header and UM message of the corresponding slot of the next downlink signal DL1. A series of processes of detection, SINR information generation, and power control information storage is completed before downlink transmission of the same time slot that received the uplink signal UL1 transmitted from the terminal UT. In this way, it is possible to transmit the power control information using the RMU header and the UM message with the next downlink signal DL1.

The terminal UT reads the RMU header including the power control information PCI and the UM message in the received downlink signal DL1, and indicates / designates the downlink signal DL1 until the uplink signal UL2 of the next frame k + 1 is transmitted. However, since it takes time to demodulate the message, it is not possible to keep up with the transmission of the uplink signal UL2 of the next frame k + 1. Therefore, the power control information read through the demodulation process is reflected in the uplink signal UL3 of “the next frame k + 2”. In other words, the transmission power control is performed based on information of two frames before, and a “two frame length delay” occurs. As a reference, current
The time difference between uplink (UL) -downlink (DL) and downlink (DL) -uplink (UL) in the iBurst (registered trademark) system is shown in the table.

  Similarly, the terminal UT can finish a series of processes including the detection process until the uplink of the next frame that received the downlink signal from the base station BS (within 1175 μsec), so that the power control information can be transmitted. it can. However, since the message including the power control information is the RMU header and the UM message that require “demodulation processing” in addition to the detection processing, the base station (BS) side receives the message including the power control information, It is not enough to reflect the power control information read by detection and demodulation in the next frame (not within 1100 μsec). For this reason, it is also reflected in “the next frame (two frames after)”. This means that downlink power control is performed using information two frames before as in the uplink. Also, information indicating a power increase instruction and a power decrease instruction is stored in the RMU header for each frame and transmitted. For this reason, the conventional transmission power control has a feature that the power level is constantly fluctuated even in a stationary state where the radio wave propagation environment is calm.

<Link adaptation: FACCH message usage>
The base station BS receives the uplink signal from the terminal UT, performs detection processing on the received uplink signal, and analyzes the FACCH message after detection processing. The FACCH message of the uplink signal conveys to the base station the power level AP (Available Power) that can be increased when the frame is an even frame, and the modulation class (CMC) of the signal that is transmitted when the frame is an odd frame. . The base station BS that has received the increaseable power value AP in the even frame performs detection processing and determines an appropriate modulation class from the SINR of the received signal and the increaseable power value AP of the terminal. The downlink FACCH message in the corresponding frame (even frame) reports the current modulation class. Therefore, the recommended class (RMC) of the modulation class used for the uplink is notified using the downlink FACCH of the next frame (odd frame). The received terminal UT performs transmission in the corresponding modulation class, but the modulation class change on the terminal UT side realizes control change in the next frame. In the FACCH of the corresponding frame, the modulation class (CMC) being used is notified. For this reason, in the uplink, the modulation class is changed in odd frames, and there is no change in even frames. In this way, the link adaptation control causes a control delay of 3 frames.

  After receiving the downlink signal, the terminal UT measures SINR by detection. From this result, the power required in the terminal UT, that is, the power to be instructed to the base station is calculated, and this is used as the power control information PCI. Power control information is stored in the UM message or RMU header with the uplink signal of the next frame, and the uplink signal of this next frame is transmitted to the base station BS. On the base station BS side, the message storing the power control information can be taken out after detection and demodulation processing. Since it passes through the “demodulation process”, it is not in time for downlink transmission in the same frame (that is, the frame immediately after reception). For this reason, data can be transmitted by changing the modulation class in the downlink of the next frame. At this time, the changed modulation class is transmitted on the FACCH (downlink even frame). The downlink changes the modulation class in even frames and does not change in odd frames. The FACCH message stores 4-bit information. In the current iBurst (registered trademark) communication system, information on the modulation class: ModClass (from 0 to 10) and the raiseable power range (from 0 to 15 dB) are allocated as follows.

Next, operations of transmission power control and link adaptation according to the present invention will be described.
<Power control using FACCH>
As described above, since the FACCH message does not need to be demodulated, the message can be acquired faster than the UM message. Utilizing this feature, transmission power control with reduced processing delay is realized. The power control information PCI is assigned to the FACCH 4 bits. As a result, power control control can be performed without waiting for demodulation processing, so that a message can be transmitted in the downlink next to the uplink, and control based on the received message can be realized in the uplink of the next frame. The downlink can be realized similarly. Further, when performing power control using the FACCH as described above, the situation changes depending on what level fluctuation is assigned to the FACCH, but it is also possible to cope with 0 dB fluctuation that does not fluctuate the power.

<Link adaptation using UM messages>
When the above processing is performed, the link adaptation information transmitted on the FACCH is stored in a message such as a UM message that needs to be demodulated. As an example, a case will be described in which information that has been transmitted so far is transmitted as a UM message. If FACCH is used for storing power control information, there will be no means for transmitting link adaptation information. Accordingly, link adaptation information is stored and transmitted in a UM message that has been used in power control until now. As a result, the link adaptation information takes time because it needs to be demodulated, but the delay amount does not change because it was originally a two-frame delay.

  In addition, when the above processing is performed, that is, in a situation where the wireless communication terminal moves at high speed, the wireless environment deteriorates. For example, in such a situation, the wireless communication terminal performs voice communication. In some cases, it is desirable to fix the modulation scheme with a small number of multi-values (for example, QPSK) and give priority to maintaining the communication connection over the communication quality. For this reason, with regard to link adaptation information, information related to a modulation scheme with a small number of multi-values is transmitted using the UM message, and communication with a modulation scheme with a small number of multi-values is performed with a wireless communication terminal. Is established, the link adaptation information is not transmitted while the wireless communication terminal is moving at high speed while transmitting information related to power control using the FACCH. Control may be performed.

  By performing the above-described operation, the necessary transmission power can be changed more quickly and timely. As a result, the throughput can be improved even for a high-speed mobile terminal that does not have a throughput according to the prior art. Further, unnecessary power is not emitted, and communication with appropriate power is possible. Further, in the conventional method, the electric power is controlled by either increasing or decreasing, but it is possible to realize the control that there is no fluctuation. It is considered that the amount of margin for the power target can be reduced by eliminating the power fluctuation due to the sequence.

  FIG. 2 is a functional block diagram of a base station according to an embodiment of the present invention. As shown in the figure, the base station 100 includes an adaptive array antenna ANT that forms an array with a plurality of antennas, a reception unit 110, a detection unit 120, a demodulation unit 130, a power control information generation unit 140, a movement state information acquisition unit 150, A control unit 160, a modulation unit 170, and a transmission unit 180 are provided. Base station 100 has a function of performing space division multiple access (SDMA) to a plurality of radio communication terminals, and has a frame configuration in which an uplink signal slot and a downlink signal slot have asymmetric slot lengths, and It is assumed that uplink and downlink signals divided into three time slots are supported. The receiving unit 110 receives a signal transmitted from a wireless communication terminal (not shown) via the adaptive array antenna ANT, and the detection unit 120 detects the received signal. In addition, the transmission unit 180 transmits a signal to the wireless communication terminal via the adaptive array antenna ANT. The demodulator 130 demodulates the received signal after detection, and the modulator 170 modulates information to be transmitted. The power control information generation unit 140 generates information related to power control to be instructed to the wireless communication terminal based on the signal received from the wireless communication terminal. The movement state information acquisition unit 150 acquires movement state information (movement speed) indicating a relative movement state between the wireless communication terminal and the own apparatus. The movement state information acquisition unit 150 includes a maximum Doppler frequency calculation unit 152 and a movement speed calculation unit 154. The maximum Doppler frequency calculation unit 152 calculates a maximum Doppler frequency representing a relative movement state between devices by subtracting a known reference frequency in advance from the frequency of a signal received from a wireless communication terminal. Further, the moving speed calculation unit 154 calculates a relative moving speed from the calculated maximum Doppler frequency using a predetermined calculation formula.

  Base station 100 further includes a storage unit (not shown), and the storage unit stores a predetermined threshold value. The control unit 160 compares the movement speed calculated by the movement state information acquisition unit 150 with a predetermined threshold, and if the movement speed exceeds the predetermined threshold, the power control information PCI is not demodulated. Referring to the correlation table, transmission unit 180 is controlled so as to transmit the information (information stored in the FACCH message) that can be read based on the correlation of the received signal to the wireless communication terminal. In addition, when the moving speed is equal to or lower than a predetermined threshold, the control unit 160 transmits the power control information PCI as a signal that needs to be demodulated (information stored in the UM message) to the wireless communication terminal. To control. The predetermined threshold value is appropriately set in advance so as to be a numerical value that does not cause fading based on the frame length, the time slot length of the downlink and uplink signals, the number of slots per frame, and the like.

  FIG. 3 is a functional block diagram of a base station according to an embodiment of the present invention, which is configured based on a desired signal power fluctuation period. As shown in the figure, the base station 200 includes an adaptive array antenna ANT that forms an array with a plurality of antennas, a reception unit 210, a detection unit 220, a demodulation unit 230, a power control information generation unit 240, a desired signal received power fluctuation period estimation. Unit 250, control unit 260, modulation unit 270, and transmission unit 280. 3 has the same configuration as that of FIG. 2 except for the desired signal received power fluctuation period estimation unit 250. The desired signal received power fluctuation period estimation unit 250 includes a maximum Doppler frequency calculation unit 252. The maximum Doppler frequency calculation unit 252 calculates a maximum Doppler frequency representing a relative movement state between apparatuses by subtracting a known reference frequency in advance from the frequency of a signal received from a wireless communication terminal. Desired signal received power fluctuation period estimation section 250 estimates a desired signal power fluctuation period based on the calculated maximum Doppler frequency. The subsequent processing is the same as in the case of FIG. 2, except that the desired signal received power fluctuation period is used instead of the moving speed, and only the set threshold value and the determination processing associated therewith are different.

  FIG. 4 is a sequence diagram illustrating a message (signal) usage pattern (FACCH message) regarding power control between the base station BS and the terminal UT according to an embodiment of the present invention. In this example, it is assumed that the terminal UT is moving at a moving speed exceeding a predetermined threshold, and the base station BS is operating to store the power control information PCI in the FACCH. In addition, although a base station will be described as an example, the configuration and processing on the terminal side are the same in principle. The terminal UT transmits an uplink signal UL1 to the base station BS. The base station BS obtains SINR (or DSSI: desired wave reception level) information based on the received signal after performing the detection process of the uplink signal UL1 of the frame k which is the current frame transmitted from the terminal UT. Based on the obtained SINR information, the power control information PCI to be instructed to the terminal UT is stored in the FACCH message of the slot corresponding to the next downlink signal DL1, and the downlink signal DL1 is transmitted. The terminal UT reads the PCI in the FACCH of the downlink signal DL1 without demodulating, and bases the uplink signal UL2 at a higher power level based on the read power control information PCI (in this case, 1 tick power increase instruction). Transmit to station BS. Thereafter, the power control information PCI based on the uplink signal UL2 of the frame k + 1 is also stored and transmitted in the FACCH of the next downlink signal DL2, and the uplink signal UL2 of the frame k + 2 of the next frame is the uplink of the previous frame k + 1. It is possible to reflect the power control information PCI based on the link signal UL1. In other words, it is possible to perform control reflecting power control information with a delay of 1 frame length (5 ms). For example, the fading phenomenon occurs once in about 8 ms when the terminal moving speed is about 50 kmph as described in the conventional example. This makes it possible to follow power control even in a radio wave propagation environment that is likely to occur. In addition, for convenience of drawing and explanation, the uplink signal and the downlink signal are described in a format occupied by one terminal, but each signal of the uplink signal and the downlink signal is divided into a plurality of slots. Note that different terminals occupy each slot, and power control as described above can be performed on a slot basis.

<Acquisition of relative movement speed between base station and terminal>
As a method for obtaining the relative speed between the base station and the wireless terminal in addition to the maximum Doppler frequency, a method for obtaining from the signal arrival timing will be described. In “High Capacity-Spatial Division Multiple Access (HC-SDMA) WTSC- 2005-032 (ATIS / ANSI)”, the wireless terminal transmits broadcast information transmitted by the base station in order to synchronize with the downlink signal transmitted by the base station. Monitor the channel burst periodically to adjust the receiving position. After determining the reception position, the wireless terminal transmits a configuration channel burst to the base station in order to know uplink transmission timing according to the distance from the base station. The base station returns a configuration burst including difference information from the reception position of the configuration channel burst to the original uplink reception position to the wireless terminal. The wireless terminal adjusts the transmission timing based on the difference information obtained from the base station. At this time, the base station can obtain the distance from the base station of the wireless terminal from the difference information of the same wireless terminal, and performs control to record the difference information for a plurality of times in the past. By examining the above, the relative speed from the base station of the wireless terminal can be obtained. Since the difference information is also shared by the wireless terminals, the relative speed can be easily acquired on the wireless terminal side.

  FIG. 5 is a sequence diagram illustrating a message flow and processing for power control between the base station BS and the terminal UT according to an embodiment of the present invention. As shown in the figure, first, in step U10, the terminal UT transmits an uplink UL signal to be basic information for power control to the base station BS. In step B10, the base station BS receives the transmitted uplink UL signal and detects the received signal (step B11). From the received signal after detection, power control information PCI to be instructed to the terminal UT is generated, and the generated power control information PCI is stored in a FACCH message that does not require demodulation and transmitted as a downlink DL signal including this FACCH message. (Step B12).

  The terminal UT receives the downlink DL signal (step U11) and detects it (step U12). Next, at step U13, the power control information PCI in the FACCH of the received signal after detection is read. Since the FACCH does not require demodulation, the power control of the next uplink UL signal is performed using the read power control information PCI (step U14). In step U15, the uplink signal UL subjected to power control is transmitted to the base station BS. In this way, a series of power control processes straddling the base station BS and the terminal UT are executed during one frame length, and power control capable of reducing / suppressing the influence of fading due to the high-speed movement of the terminal becomes possible. Finally, the base station BS receives the uplink UL signal whose power has been adjusted (step B13).

FIG. 6 is a flowchart showing processing of a wireless communication method according to an embodiment of the present invention. As shown in the figure, in step S10, a signal from the counterpart terminal is received. In step S11, the received signal is detected, and power control information PCI to be instructed to the counterpart terminal is generated from the detected signal (step S12). Next, in step S13, the relative moving speed between the own device and the partner terminal is calculated based on the maximum Doppler frequency. Compare the moving speed with a predetermined threshold,
“Movement speed> Predetermined threshold”
If YES, the process proceeds to step S15, where the power control information PCI is stored in the FACCH, which is a signal that does not need to be demodulated, and transmitted at the next transmission timing. If the condition of step S14 is not satisfied, the process proceeds to step S16, where the power control information PCI is stored in the RMU or UM, which is a signal that needs to be demodulated, and transmitted at the next transmission timing. When the process of step S15 is performed, since the own device or the partner terminal is moving at a high speed exceeding a predetermined threshold, high-speed power control corresponding to the current propagation environment can be realized quickly so that the high-speed movement can be followed. It is. On the other hand, when the process of step S16 is performed, the own device or the partner terminal is less than a predetermined threshold value and is considered to be able to sufficiently cope with the current propagation environment, so that the power control information PCI is a signal that needs to be demodulated. Send.

  The present invention realizes a system that can cope with high-speed fading fluctuations by performing power control using a FACCH that does not require demodulation as a transmission signal of a power control message. That is, in the present invention, in a radio communication base station apparatus having a plurality of antennas, when the speed at which a fading phenomenon is expected has been reached, the current protocol is changed, and transmission power control information is put into FACCH, By including link adaptation information in RMU and UM messages, it is possible to reduce the delay time of transmission power control, suppress the influence of fading, and improve the power control tracking capability.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each unit, each means, each step, etc. can be rearranged so as not to be logically contradictory, and a plurality of means, steps, etc. can be combined or divided into one. It is. Moreover, it is also possible to distribute each function which implement | achieves this invention between a base station and a radio | wireless communication terminal device. For example, a function for calculating relative speed information may be arranged in the base station, and the wireless communication terminal apparatus may receive the relative speed information from the base station to realize the present invention.

It is a hardware block diagram of the base station by this invention. It is a functional block diagram of a base station according to an embodiment of the present invention. It is a functional block diagram of a base station according to an embodiment of the present invention. It is a sequence diagram explaining the message usage pattern about the power control of the base station BS and the terminal UT according to an embodiment of the present invention. It is a sequence diagram explaining the flow of the message about the power control of the base station BS and the terminal UT and the processing according to an embodiment of the present invention. It is a flowchart which shows the process of the radio | wireless communication method by one embodiment of this invention. It is a sequence diagram explaining the message (signal) usage form (RMU header, UM message) about power control in the prior art.

Explanation of symbols

10 Base station 11 RF processor 12 Signal processor 100, 200 Base station 110, 210 Receiver 120, 220 Detector 130, 230 Demodulator 140, 240 Power control information generator 150 Movement state information acquisition unit 250 Desired signal power fluctuation Period estimation unit 152, 252 Maximum Doppler frequency calculation unit 154 Movement speed calculation unit 160, 260 Control unit 170, 270 Modulation unit 180, 280 Transmission unit ANT Adaptive array antenna AP Increaseable power value BS Base station UT Terminal PCI Power control information DL1 -3 Downlink signal UL1-3 Uplink signal

Claims (7)

A receiving unit for receiving a signal transmitted from the counterpart wireless communication device;
A transmission unit for transmitting a signal to the counterpart wireless communication device;
A power control information generating unit that generates information on power control to be instructed to the counterpart wireless communication device based on a signal received from the counterpart wireless communication device;
A movement state information acquisition unit for acquiring movement state information indicating a relative movement state between the counterpart wireless communication device and the own device;
A signal that can read the information on the power control generated by the power control information generation unit based on the movement state information acquired by the movement state information acquisition unit based on the correlation of the received signal. Or a control unit that controls the transmission unit to transmit to the counterpart wireless communication device as a signal that requires demodulation;
A wireless communication apparatus comprising: The wireless communication device according to claim 1,
The movement state information is a relative movement speed between the counterpart wireless communication device and the own device,
The control unit, when the relative movement speed exceeds a predetermined threshold,
Controlling the transmission unit to transmit the information related to the power control as a signal from which the information can be read based on the correlation of the received signal to the counterpart wireless communication device;
A wireless communication apparatus. The wireless communication device according to claim 2,
When the relative moving speed is equal to or less than the predetermined threshold,
The transmission unit is configured to transmit at least information relating to link adaptation to be transmitted to the counterpart communication device to the counterpart radio communication device as a signal from which the information can be read based on a correlation of received signals. Control
And, the transmitter is controlled so that the information related to the power control is transmitted to the counterpart wireless communication device as a signal that requires demodulation.
A wireless communication apparatus. In a wireless communication method for performing wireless communication between a first wireless communication device and a second wireless communication device,
A power control information generating step for generating information on power control to be instructed to the second wireless communication device based on a signal received by the first wireless communication device from the second wireless communication device;
A movement state information acquisition step in which the first wireless communication device acquires movement state information indicating a relative movement state between the second wireless communication device and the first wireless communication device;
The first wireless communication device reads the generated information related to the power control based on the correlation of the received signal in accordance with the movement state information acquired in the movement state information acquisition step. A control step of transmitting to the second wireless communication device as a possible signal or a signal requiring demodulation;
A wireless communication method comprising: The wireless communication method according to claim 4, wherein
The second wireless communication apparatus reads the information received from the first wireless communication apparatus, including the information related to the power control, based on the correlation of the received signal, and uses the read information related to the power control. Based on the transmission step of controlling the transmission power of the own device and transmitting to the first wireless communication device,
A wireless communication method, further comprising: A receiving unit for receiving a signal transmitted from the counterpart wireless communication device;
A transmission unit for transmitting a signal to the counterpart wireless communication device;
A power control information generating unit that generates information on power control to be instructed to the counterpart wireless communication device based on a signal received from the counterpart wireless communication device;
Based on a signal received from the counterparty wireless communication device, a desired signal received power fluctuation period estimation unit that estimates a desired signal power fluctuation period;
Reading the information on the power control generated by the power control information generation unit based on the correlation of the received signal according to the desired signal power fluctuation cycle estimated by the desired signal power fluctuation cycle estimation unit. A control unit that controls the transmission unit to transmit to the counterpart wireless communication device as a signal that can be transmitted or a signal that requires demodulation;
A wireless communication apparatus comprising: In a wireless communication method for performing wireless communication between a first wireless communication device and a second wireless communication device,
A power control information generating step for generating information on power control to be instructed to the second wireless communication device based on a signal received by the first wireless communication device from the second wireless communication device;
A desired signal power fluctuation period estimating step in which the first wireless communication apparatus estimates a desired signal power fluctuation period based on a signal received from the second wireless communication apparatus;
The first wireless communication apparatus determines the generated information related to the power control based on the correlation of the received signal according to the desired signal power fluctuation period estimated in the desired signal power fluctuation period estimation step. A control step of transmitting to the second wireless communication device as a signal that can be read or a signal that requires demodulation;
A wireless communication method comprising:

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