JP2010056714A - Radio communication device, radio communication method, and radio communication program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cause another radio communication device which receives transmitted signals suitably to extract signals by executing the calculation of weight by an adaptive array technique for each of frequency domains divided into plural to a PRU when performing reception and using appropriate weight when performing transmission. <P>SOLUTION: A base station 120 as the radio communication device executes the calculation of the weight in the adaptive array technique for each of the frequency domains divided into plural to the PRU of reference signals received from a PHS terminal 110 as another radio communication device respectively, and includes a signal generation part 232 for reflecting the calculated weight on received signals and generating desired signals, a weight selection part 234 for selecting the weight satisfying a prescribed condition from the calculated weight, and a signal transmission part 222 for transmitting the signals reflecting the selected weight on the entire frequency domains of the PRU. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus having a plurality of antenna elements, a wireless communication method, and a wireless communication program.

  In recent years, terminal devices as wireless communication devices represented by PHS (Personal Handy phone System) and mobile phones have become widespread, and it has become possible to make calls and obtain information regardless of location or time. Especially in recent years, the amount of available information has been increasing, and high-speed and high-quality wireless communication systems have been introduced to download large amounts of data.

  In such wireless communication, it is necessary to duplicate signals in order to transmit and receive. Typical duplexing methods include TDD (Time Division Duplex) that switches transmission and reception by time division and FDD (Frequency Division Duplex) that duplexes transmission and reception by changing the frequency. Also, as a method for multiple access to communicate with a plurality of terminal devices at the same time, TDMA (Time Division Multiple Access) for switching a plurality of terminal devices by time division, FDMA (Frequency) for dividing a frequency band Typical examples are Division Multiple Access (frequency division multiple access) and CDMA (Code Division Multiple Access) that multiplies a different code for each terminal device.

  For example, as next-generation PHS communication standards that enable high-speed digital communication, there are ARIB (Association of Radio Industries and Businesses) STD T95 (Non-patent Document 1) and PHS MoU (Memorandum of Understanding). , OFDMA / TDMA TDD Broadband Wireless Access System (next generation PHS system) is being formulated.

  OFDMA (Orthogonal Frequency Division Multiple Access) performs multiple access in OFDM (Orthogonal Frequency Division Multiplexing). OFDM is a method developed from FDM (Frequency Division Multiple), which divides a carrier signal into a large number of subcarriers on the frequency axis and orthogonalizes the phase of a signal wave between adjacent subcarriers. This is a method of effectively using the frequency band by partially overlapping the subcarrier bands. In OFDM, all subcarriers are occupied by one terminal apparatus, but in OFDMA, several subcarriers (for example, 24) are grouped to form a subchannel, and a plurality of terminal apparatuses share all subchannels. Multiple access. For example, the sub-channel divides the frequency band of 18 MHz into 20 pieces.

  Further, in the next generation PHS system, in addition to OFDMA, multiple access by TDMA is performed. TDMA is a system in which a frequency is divided into a plurality of time slots on a time axis and communication is performed with a plurality of opponents. At present, it is assumed that the uplink (Up Link: terminal device to base station) and the downlink (Down Link: base station to terminal device) are each divided into four. That is, in the next-generation PHS system, the communication block is subdivided into both the frequency axis and the time axis, and communication is efficiently performed by dynamically allocating the communication block to a large number of terminal devices. A communication block defined by one time slot in one subchannel is called a PRU (Physical Resource Unit), and it is assumed that 76 to 80 PRUs are used per base station.

  As described above, the base station can use 20 subchannels, one of which is used as a control channel (CCH), and the remaining subchannels are dynamically allocated to terminal devices (DCA: Dynamic Channel Assign). An anchor channel or an extra channel is allocated to the PRU included in the subchannel used for communication. One anchor channel is assigned to each terminal device, and includes a map of PRUs to which an extra channel for the terminal device is assigned. An extra channel is a channel that actually includes data, and a plurality of extra channels are assigned to one terminal device according to the amount of data and communication status. The notification of the extra channel assignment by the map included in the anchor channel is referred to as FM-mode (Fast access channel based on Map-Mode).

  The anchor channel is assigned to the PRU having the best communication quality obtained by performing carrier sense on all PRUs. The extra channel is basically not subjected to carrier sense. However, when the base station newly uses a PRU that is not performing communication, the extra channel is assigned after performing carrier sense. Thus, since the base station can dynamically change the position and number of extra channels via the anchor channel, it is possible to transmit and receive a large amount of data at high speed.

  In the next-generation PHS system, an adaptive array antenna technology that uses a plurality of antennas to control directivity patterns can be adopted as a means for improving communication quality while maintaining communication speed.

  Such an adaptive array antenna technique is a technique for generating a composite wave by controlling the phases of radio waves transmitted from a plurality of antennas and controlling the traveling direction of the composite wave. Thereby, since it is possible to transmit a desired radio wave only in a predetermined direction, it is possible to reduce radio wave interference generated between base stations and to extend the radio wave transmission distance.

  Specifically, by forming beamforming using adaptive array technology, radio waves can be focused in a predetermined direction, and by forming null steering, interference with other base stations can be minimized. It becomes possible. That is, if a communication terminal as a communication partner can be specified at a certain moment, it is possible to form beam forming in the direction of the specified communication terminal and to form null steering in a direction other than the direction of the specified communication terminal. Become. In a base station that can use such an adaptive array technology, a plurality of terminal devices can be simultaneously accommodated in one base station by the beam forming described above.

  Furthermore, high-speed data communication such as IEEE 802.11 or WiMAX (Worldwide Interoperability for Microwave Access) (for example, Non-Patent Document 2) is assumed for transmission (downlink) from the base station to the terminal device. In such high-speed data communication, it may be considered that the communication quality required for each terminal device varies greatly with the increase in data communication. At this time, a difference also occurs in the SINR (Signal to Interference and Noise Ratio) required by each terminal device, and an asymmetric traffic environment is expected between upstream and downstream. In such an asymmetric traffic environment, there is a demand for suppressing mutual interference while satisfying the desired communication quality of the terminal device.

  Therefore, by determining the weight of the transmission signal for each user to be supplied to the plurality of antennas using the correlation matrix obtained by performing the weighted sum related to the plurality of correlation matrices corresponding to the propagation path information of the plurality of users, Has disclosed a technique capable of reducing the mutual user interference in the transmitted signal and improving the number of accommodated users (for example, Patent Document 1).

When beam forming is performed using the adaptive array technique described in Patent Document 1 described above, appropriate beam forming is performed to some extent in both uplink and downlink for each terminal apparatus communicating with the base station, that is, for each PRU in the next generation PHS standard. Can be done.
JP 2002-261670 A ARIB (Association of Radio Industries and Businesses) STD-T95 "Mobile WiMAX-Part I: A Technical Overview and Performance Evaluation" Prepared on Behalf of the WiMAX Forum, February 21, 2006, http://www.intel.com/netcomms/technologies/wimax/WiMAX_Overview_v2.pdf

  However, when the PRU assigned to one terminal apparatus is analyzed in detail, it can be seen that frequency selective fading occurs even in one PRU.

  FIG. 8 is an explanatory diagram for explaining fading that occurs in the PRU in the next-generation PHS communication standard. In the next-generation PHS communication standard, one PRU is composed of 24 subcarriers. In FIG. 8, the horizontal axis indicates the frequency of each subcarrier in the PRU, and the vertical axis indicates the strength of the received signal. .

  As shown in FIG. 8, even in one PRU, the trajectory of the signal strength of the received signal that should be essentially flat may fluctuate significantly. Therefore, weight calculation is not performed for all subcarriers of one PRU at once, and the weight is calculated appropriately for each divided area by dividing the subcarriers to some extent (for example, dividing into four) and performing weight calculation for each. It is possible to suppress the influence of fading.

  However, if the weight calculated by dividing the subcarrier to some extent through reception of the reference signal is reflected as it is in each division of the transmission subcarrier as it is, a problem may occur depending on the terminal device. This is because the terminal device that is the transmission destination may perform equalization processing such as linear interpolation in the range of 1 PRU.

  FIG. 9 is an explanatory diagram for explaining a problem of a signal received in the terminal device. FIG. 9A shows amplitude discontinuity, and FIG. 9B shows phase discontinuity.

  As shown in the diagram of the processing on the transmission side in FIG. 9, the conventional base station divides the PRU frequency domain of the received reference signal into a plurality of parts, calculates weights for each of the divided frequency domains, and reflects the calculated weights. The received signal is extracted. When the base station transmits a signal, a signal to be transmitted (indicated by a dotted line in FIG. 9) is output with a different weight for each divided frequency region (multiple subcarriers) calculated at the time of reception (see FIG. 9). 9) (indicated by a solid line).

  On the other hand, as shown in the reception side processing diagram in FIG. 9, the terminal device receives a signal in which the regions are discontinuous as they are. Therefore, the terminal apparatus performs interpolation (indicated by a dotted line in the receiving side process in FIG. 9) by performing equalization processing such as linear interpolation on a portion where the signal is discontinuous. Therefore, the signal subjected to linear interpolation is not smooth and causes signal quality degradation.

  In view of such a problem, the present invention reduces the influence of fading by performing weight calculation using adaptive array technology for each frequency region divided into a plurality of PRUs when receiving, and when transmitting. An object of the present invention is to provide a wireless communication device, a wireless communication method, and a wireless communication program that can be appropriately extracted by other wireless communication devices that receive transmitted signals by using appropriate weights. .

  In order to solve the above problems, a typical configuration of the present invention is a wireless communication device that communicates with another wireless communication device using the OFDMA method, and includes a plurality of antenna elements and other wireless communication devices. Through a plurality of antenna elements, a signal receiving unit for receiving the reference signal, a weight calculating unit for performing weight calculation in the adaptive array technique for each frequency region divided into a plurality of frequency regions for the PRU of the received reference signal, and A signal generation unit for generating a desired signal by reflecting the calculated weight in the received signal, a weight selection unit for selecting a weight satisfying a predetermined condition from the calculated weights, and the selected weight And a signal transmission unit that transmits a signal reflected in the entire frequency region of the PRU via a plurality of antenna elements.

  With this configuration, when transmitting a signal while suppressing the influence of fading caused by performing weight calculation for each frequency region obtained by dividing the PRU into a plurality of times at the time of signal reception, the weight used at the time of reception is From this, it is possible to select one weight satisfying a predetermined condition and use it in the entire frequency range of the PRU. As a result, continuity of the transmission signal can be ensured, and in other wireless communication devices that receive the transmitted signal, signal discontinuity occurs due to the wireless communication device outputting (transmitting) signals with different weights. Disappears. Therefore, other wireless communication apparatuses can avoid quality degradation based on the discontinuity of the received signal.

  The weight selection unit may select a weight in which a mean square error between the measured value of the received reference signal and the theoretical value of the reference signal satisfies a predetermined condition.

  A weight with a smaller mean square error (MSE: Mean Square Error) between the measured value of the received reference signal and the theoretical value (reference value) of the reference signal can be considered to contain no accidental or sudden components. High accuracy (likelihood). Therefore, it is possible to perform transmission with high accuracy by using the weight having the smallest mean square error.

  The weight selection unit may select a weight in which the intensity of the signal received in each of the divided frequency regions satisfies a predetermined condition.

  By using RSSI (Received Signal Strength Indicator), SINR, and CINR (Carrier to Interference and Noise Ratio) as signal strength, it is possible to appropriately grasp the communication quality. It becomes possible. That is, RSSI is the radio field intensity of all received radio waves, SINR is the ratio between the desired signal and noise including interference, and CINR is the ratio between the desired carrier and noise including interference. That is, it is assumed that a signal having a larger RSSI, SINR, or CINR has higher reliability.

  Therefore, the weight calculated based on the signal having the highest signal strength in the frequency domain divided into a plurality of parts has high reliability. By selecting this, the transmission weight can be suitably selected. It becomes possible.

  In order to solve the above-described problem, another exemplary configuration of the present invention is a wireless communication method using a wireless communication apparatus that communicates with another wireless communication apparatus using the OFDMA method. The reference signal from the device is received, and the PRU of the received reference signal is subjected to weight calculation in adaptive array technology for each of the divided frequency regions, and a plurality of antenna elements provided in the wireless communication device are A desired signal is generated by reflecting the calculated weight in the signal received via the selected weight, a weight satisfying a predetermined condition is selected from the calculated weight, and the selected weight is reflected in the entire frequency region of the PRU. The transmitted signal is transmitted through a plurality of antenna elements.

  In order to solve the above-described problem, still another typical configuration of the present invention is a wireless communication device that allows a computer including a plurality of antenna elements to function as a wireless communication device that communicates with another wireless communication device using the OFDMA method. A communication program, comprising: a signal receiving unit that receives a reference signal from another wireless communication device; and a weight of adaptive array technology for each frequency region divided into a plurality of frequency regions with respect to the PRU of the received reference signal A weight calculation unit for performing each calculation, a signal generation unit for generating a desired signal by reflecting the calculated weight on a signal received via a plurality of antenna elements, and a predetermined condition among the calculated weights A weight selection unit for selecting a weight and a signal reflecting the selected weight in the entire frequency region of the PRU Wherein a signal transmitting unit that transmits through the element, to that to function.

  The components corresponding to the technical idea of the wireless communication apparatus described above and the description thereof can be applied to the wireless communication method and the wireless communication program.

  As described above, the radio communication apparatus of the present invention reduces the influence of fading by performing weight calculation using adaptive array technology for each frequency region divided into a plurality of PRUs when receiving, and transmits the PRU. In this case, by using an appropriate weight, it becomes possible for another wireless communication device that receives the transmitted signal to suitably extract the signal.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  A wireless communication device represented by a PHS terminal, a mobile phone, or the like constructs a wireless communication system that performs wireless communication with a base station that is fixedly arranged at a predetermined interval. Here, the entire wireless communication system will be described first, and then a specific configuration of a base station as a wireless communication apparatus will be described. In this embodiment, a PHS terminal is cited as another wireless communication device. However, the present invention is not limited to such a case. A mobile phone, a notebook personal computer, a PDA (Personal Digital Assistant), a digital camera, a music player, a car navigation system is used. Various electronic devices capable of wireless communication, such as portable televisions, game devices, DVD players, and remote controllers, can also be used as other wireless communication devices.

(Wireless communication system 100)
FIG. 1 is an explanatory diagram showing a schematic connection relationship of the wireless communication system according to the present embodiment. The wireless communication system 100 includes a PHS terminal 110 (110A, 110B), a base station 120 (120A, 120B), a relay station 130, an ISDN (Integrated Services Digital Network) line, the Internet, a dedicated line, and the like. The communication network 140 and the relay server 150 are included.

  In such a wireless communication system 100, when a user connects a communication line from his / her PHS terminal 110A to another PHS terminal 110B, the PHS terminal 110A makes a wireless connection request to the base station 120A within the communicable range. . The base station 120A that has received the wireless connection request requests the relay server 150 to establish a communication connection with the communication partner (PHS terminal 110B) via the communication network 140, and the relay server 150 receives the location registration information of the other PHS terminal 110B. The base station 120B within the radio communication range of the other PHS terminal 110B is selected, a communication path between the base station 120A and the base station 120B is secured, and communication between the PHS terminal 110A and the PHS terminal 110B is established. .

  In such a wireless communication system 100, various techniques are employed to improve the communication speed and communication quality between the PHS terminal 110 and the base station 120. In this embodiment, for example, next-generation PHS communication technologies such as ARIB STD T95 and PHS MoU are adopted, and wireless communication based on the OFDMA / TDMA-TDD scheme is executed between the PHS terminal 110 and the base station 120. .

  FIG. 2 is an explanatory diagram for explaining a frame configuration according to the present embodiment. OFDMA / TDMA has a two-dimensional map in the time axis direction and the frequency direction. A plurality of subchannels are arranged with a uniform baseband distance in the frequency axis direction, and a PRU is arranged for each time slot (TDMA slot) in each subchannel.

  In such a next-generation PHS system, an adaptive array antenna technology that uses a plurality of antennas to control directivity patterns can be employed as one means for improving communication quality while maintaining communication speed.

  Such adaptive array antenna technology is a technology that generates a composite wave by controlling the phase of radio waves transmitted from a plurality of antennas using a weight calculated from a reference signal, and controls the traveling direction of the composite wave. is there. Thereby, since it is possible to transmit a desired radio wave only in a predetermined direction, it is possible to reduce radio wave interference generated between base stations and to extend the radio wave transmission distance.

  Here, if one PRU is analyzed in detail, frequency selective fading may occur even in one PRU. Therefore, the weight calculation is not performed for all subcarriers of one PRU at once, and the weight is calculated appropriately for each divided area by dividing the subcarriers to some extent (for example, dividing into four) and performing the respective weight calculations. It is possible to suppress the influence of fading.

  However, if the weight calculated by dividing the subcarrier to some extent through reception of the reference signal is reflected as it is in each division of the transmission subcarrier as it is, a problem may occur depending on other wireless communication devices that receive the signal. There is a case.

  Therefore, when receiving a signal, it is necessary to subdivide the PRU and calculate the weight for each region, but when transmitting the signal, a weight that can ensure the continuity of the signal in order to avoid quality degradation. It is required to transmit using.

  Hereinafter, a specific configuration and operation of the base station 120 as a wireless communication device that performs wireless communication with the PHS terminal 110 as another wireless communication device will be described.

(Base station 120)
FIG. 3 is a block diagram showing a schematic configuration of the base station. The base station 120 includes a base station control unit 210, a base station memory 212, a base station wireless communication unit 214, and a base station wired communication unit 216 connected to various servers including the relay server 140 via the communication network 130. The antenna element 218 includes a plurality of antenna elements 218.

  The base station control unit 210 manages and controls the entire base station 120 by a semiconductor integrated circuit including a central processing unit (CPU). In addition, the base station control unit 210 controls communication connection of the PHS terminal 110 to the communication network 130 and other PHS terminals 110 using the program in the base station memory 212. The base station memory 212 includes a ROM, a RAM, an EEPROM, a nonvolatile RAM, a flash memory, an HDD, and the like, and stores a program processed by the base station control unit 210.

  The base station radio communication unit 214 includes a signal reception unit 220 and a signal transmission unit 222. The base station radio communication unit 214 performs array processing on signals (including reference signals) received from a plurality of antenna elements 218 to communicate with the PHS terminal 110. Establish and send / receive data.

  In addition, the base station wireless communication unit 214 can perform an adaptive array function using a plurality of antenna elements 218. By forming the beam forming and null steering using the weights between the antenna elements 218, the base station wireless communication unit 214 can transmit and receive radio waves. Directivity can be changed dynamically.

  Here, when the signal is received by the signal receiving unit 220, beam forming and null steering are formed using the weight calculated by the weight calculating unit 230 described later.

  When a signal is transmitted by the signal transmission unit 222, the weight selected by the weight selection unit 234 described later is reflected in the entire frequency region of the PRU to form beam forming and null steering.

  Beam forming is to increase the radio wave intensity by matching the phases of the radio waves output from the plurality of antenna elements 218, and null steering is to cancel the radio wave intensity by shifting the phase of the radio waves.

  In the present embodiment, the base station control unit 210 also functions as a weight calculation unit 230, a signal generation unit 232, and a weight selection unit 234.

  The weight calculation unit 230 calculates the weight by the adaptive array technique for each frequency region divided into a plurality of frequency regions divided into a plurality of frequency regions with respect to the PRU of the reference signal received via the signal reception unit 220.

  In this embodiment, the weight calculation unit 230 divides the 900 kHz frequency region into four (225 kHz each) with respect to the PRU of the reference signal. In the present embodiment, the weight calculation unit 230 divides the frequency domain of the PRU of the reference signal (known signal) into four, but it goes without saying that the present invention is not limited to this. However, the upper limit of the number of divisions is the number of subchannels (24 in the next-generation PHS communication standard) or the number of reference signals.

  The signal generation unit 232 generates (extracts) a desired signal by reflecting each weight calculated by the weight calculation unit 230 in the signal received by the signal reception unit 220 via the plurality of antenna elements 218.

  As a result, it is possible to generate (synthesize) signals while significantly reducing the influence of fading.

  The weight selection unit 234 selects a weight that satisfies a predetermined condition from the weights calculated by the weight calculation unit 230.

  FIG. 4 is an explanatory diagram for explaining processing of the weight calculation unit and the weight selection unit.

  As shown in FIG. 4, the weight calculation unit 230 calculates a weight for each narrow band range obtained by dividing the PRU for reception, and the weight selection unit 234 calculates the weight used for the entire frequency region (wideband) of the PRU for transmission. select.

  In the present embodiment, the weight selection unit 234 selects a weight in which the mean square error between the measured value of the reference signal received by the signal receiving unit 220 and the theoretical value of the reference signal satisfies a predetermined condition (see FIG. 4A). . Specifically, a weight (weight B in FIG. 4A) having the smallest mean square error between the measured value of the reference signal received by the signal receiving unit 220 and the theoretical value of the reference signal obtained in advance is selected.

FIG. 5 is a constellation diagram for explaining the mean square error. As an example, a mean square error of a signal with a modulation scheme of QPSK (Quadrature Phase Shift Keying) is given. As shown in FIG. 5, the mean square error (MSE) in this embodiment is the theoretical value of the reference signal (indicated by a black circle in FIG. 5) and the actual value of the received reference signal (indicated by a white circle in FIG. 5). It can be calculated by introducing the difference into Equation 1.

  Therefore, the weight having the smallest average deviation (error) of the actually measured value with respect to the theoretical value of the reference signal, that is, the smallest mean square error, is the most accurate weight.

  Since the weight selection unit 234 selects the weight with the smallest mean square error, the signal transmission unit 222 can reflect the most probable weight in the entire frequency region of the PRU, and can transmit the signal with high accuracy. Transmission can be performed.

  Further, the weight selection unit 234 selects a weight in which the intensity of the signal received in each of the divided frequency regions satisfies a predetermined condition, as shown in FIG. 4B, instead of the above-described mean square error. Also good.

  By using RSSI, SINR, CINR, etc. as the signal strength, it is possible to appropriately grasp the communication quality. That is, RSSI is the radio field intensity of all received radio waves, SINR is the ratio between the desired signal and noise including interference, and CINR is the ratio between the desired carrier and noise including interference. That is, it is assumed that a signal having a larger RSSI, SINR, or CINR has a higher reliability.

  Therefore, the weight (weight C in FIG. 4B) calculated based on the signal having the highest signal intensity in the frequency domain divided into a plurality of parts is highly reliable, and this is selected. Thus, it becomes possible to select the transmission weight more favorably.

  In the present embodiment, the weight selection unit 234 selects the weight with the smallest mean square error between the actual value of the reference signal received by the signal receiving unit 220 and the theoretical value of the reference signal, but is not limited thereto. The average square error between the actually measured value and the theoretical value of the reference signal value may be selected through a complex condition such as a weight in which the signal strength (for example, CINR) is equal to or greater than a predetermined value.

  As described above, the base station 120 as the wireless communication apparatus according to the present embodiment suppresses the influence of fading caused by performing weight calculation for each frequency region obtained by dividing the PRU at the time of signal reception. When transmitting a signal, it is possible to select one weight satisfying a predetermined condition from the weights used at the time of reception and use it in the entire frequency region of the PRU. Therefore, the continuity of the transmission signal can be ensured, and in other PHS terminals 110 that receive the transmitted signal, the discontinuity of the signal due to the base station 120 outputting (transmitting) the signal with different weights can be avoided. Can do.

  The computer also provides a program that functions as the base station 120 as a wireless communication device and a recording medium that records the program.

(Wireless communication method)
Next, a wireless communication method for performing wireless communication using the base station 120 described above will be described.

  6 and 7 are flowcharts showing a processing flow of the wireless communication method according to the present embodiment. FIG. 6 shows a processing flow on the receiving side of the base station, and FIG. 7 shows a processing flow on the transmitting side of the base station. Shows the flow.

  As shown in FIG. 6, the signal receiving unit 220 receives a signal from the PHS terminal 110 via the plurality of antenna elements 218 (S300: YES in the signal receiving step), and whether or not the received signal is a reference signal. Determination (S302: reference signal determination step). If it is a reference signal (YES in S302), the weight calculation unit 230 calculates the weight by the adaptive array technique for each frequency region divided into a plurality of frequency regions for the received PRU of the reference signal (S304: weight calculation step) ).

  After the weight calculation step (S304), it is determined whether or not the weight calculation is completed for all the divided frequency regions (frequency bands) (S306: calculation completion determination step), and when the weight calculation is completed (YES in S306), the calculation is performed. The weight is saved in the base station memory 212 (S308: weight saving step).

  Further, if it is determined that the signal received by the signal receiving unit 220 is not a reference signal (NO in S302), a desired signal is generated reflecting the weight stored in the base station memory 212 in the weight storage step S308 ( S310: Signal generation step).

  On the other hand, as shown in FIG. 7, when a signal to be transmitted is generated (S350: YES in the transmission signal generation step), it is determined whether or not the weight is updated in the above-described weight storage step S308 (S352: update determination step). If so, the weight selection unit 234 calculates a predetermined condition from the weights calculated by the weight calculation unit 230 and stored in the base station memory 212 (in this embodiment, the average of the theoretical value and the actual measurement value of the reference signal). A weight satisfying the least square error) is selected (S354: weight selection step). If not updated, the weight used last time is used repeatedly.

  Then, the signal transmission unit 222 generates a signal by reflecting the weight selected in the weight selection step S352 in the entire frequency region of the PRU (S356: weight reflection step), and transmits the signal via the plurality of antenna elements 218 (S358). : Signal transmission step).

  Also in the wireless communication method according to the present embodiment, when receiving, the PRU is subjected to weight calculation by adaptive array technology for each frequency region divided into a plurality of times, and the effect of fading is reduced. By using an appropriate weight, other wireless communication devices that receive the transmitted signal can suitably extract the signal. Therefore, the PHS terminal 110 can avoid quality degradation based on the discontinuity of the received signal.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above embodiment, the base station 120 has been described as a wireless communication device and the PHS terminal 110 has been described as another wireless communication device, but it goes without saying that the relationship may be reversed.

  It should be noted that each step in the processing of the wireless communication method and the wireless communication program in this specification does not necessarily have to be processed in time series in the order described in the flowchart, and may include processing in parallel or by a subroutine.

  The present invention can be used for a wireless communication apparatus, a wireless communication method, and a wireless communication program having a plurality of antenna elements.

It is explanatory drawing which showed the schematic connection relation of the radio | wireless communications system concerning this embodiment. It is explanatory drawing for demonstrating the flame | frame structure concerning this embodiment. It is the block diagram which showed the schematic structure of the base station. It is explanatory drawing for demonstrating the process of a weight calculation part and a weight selection part. It is a constellation diagram for explaining a mean square error. It is the flowchart which showed the flow of the process of the radio | wireless communication method concerning this embodiment. It is the flowchart which showed the flow of the process of the radio | wireless communication method concerning this embodiment. It is explanatory drawing for demonstrating the fading generate | occur | produced in PRU in a next-generation PHS communication standard. It is explanatory drawing for demonstrating the malfunction of the signal received in the terminal device.

Explanation of symbols

100 ... Wireless communication system 110 ... PHS terminal (other wireless communication device)
120 ... base station (wireless communication device)
130 ... relay station 140 ... communication network 150 ... relay server 210 ... base station control unit 212 ... base station memory 214 ... base station wireless communication unit 216 ... base station wired communication unit 218 ... antenna element 220 ... signal receiving unit 222 ... signal transmission Unit 230 ... Weight calculation unit 232 ... Signal generation unit 234 ... Weight selection unit

Claims (5)

A wireless communication device that communicates with another wireless communication device using an OFDMA scheme,
A plurality of antenna elements;
A signal receiving unit for receiving a reference signal from the other wireless communication device;
A weight calculation unit for performing weight calculation in adaptive array technology for each frequency region divided into a plurality of divided frequency regions with respect to the PRU of the received reference signal;
A signal generation unit for generating a desired signal by reflecting the calculated weight in a signal received via the plurality of antenna elements;
A weight selection unit for selecting a weight satisfying a predetermined condition from the calculated weights;
A signal transmission unit that transmits a signal reflecting the selected weight in the entire frequency region of the PRU via the plurality of antenna elements;
A wireless communication apparatus comprising:   The radio communication apparatus according to claim 1, wherein the weight selection unit selects a weight in which a mean square error between the measured value of the received reference signal and the theoretical value of the reference signal satisfies a predetermined condition.   The radio communication apparatus according to claim 1, wherein the weight selection unit selects a weight in which the intensity of a signal received in each of the divided frequency regions satisfies a predetermined condition. A wireless communication method using a wireless communication device that communicates with another wireless communication device using an OFDMA method,
Receiving a reference signal from the other wireless communication device;
With respect to the PRU of the received reference signal, weight calculation in adaptive array technology is performed for each frequency region divided into a plurality of frequency ranges,
Reflecting the calculated weight on a signal received via a plurality of antenna elements provided in the wireless communication device to generate a desired signal,
Select a weight satisfying a predetermined condition from the calculated weights,
A radio communication method characterized by transmitting a signal reflecting the selected weight in the entire frequency range of the PRU through the plurality of antenna elements. A wireless communication program that causes a computer connected to a plurality of antenna elements to function as a wireless communication device that communicates with another wireless communication device using the OFDMA method,
The computer,
A signal receiving unit for receiving a reference signal from the other wireless communication device;
A weight calculation unit for performing weight calculation in adaptive array technology for each frequency region divided into a plurality of divided frequency regions with respect to the PRU of the received reference signal;
A signal generation unit for generating a desired signal by reflecting the calculated weight in a signal received via the plurality of antenna elements;
A weight selection unit for selecting a weight satisfying a predetermined condition from the calculated weights;
A signal transmission unit that transmits a signal reflecting the selected weight in the entire frequency region of the PRU via the plurality of antenna elements;
A wireless communication program characterized by being made to function.

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