JP2007295495A - Wireless communication device and transmission signal calibrating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To permit calibration data adapted to the variation of environmental condition to be used, even when the calculation of the calibration data is not completed. <P>SOLUTION: The wireless communication device comprises: a calculation unit 141 for operating the calibration data; a memory region B152 for storing the calibration data calculated by the calculation unit 141 in association with an environmental condition upon calculation which shows an environment when the calibration data is calculated; a calibration data obtaining unit 142 for obtaining the calibration data corresponding to the present environment from the memory region B152 based on the environmental condition upon calculation stored in the memory region B152 and a present environmental condition, showing the present environment; and a modem unit 130 for calibrating the transmission signal based on the obtained calibration data. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  Some wireless communication devices perform calibration of a transmission signal in order to remove the influence of its own characteristics on the wireless signal (for example, Patent Document 1 and Patent Document 2). . Specifically, the wireless communication device calculates calibration data indicating the characteristics of the wireless communication device, and calibrates the transmission signal based on the calibration data.

Since the characteristics of the radio communication device vary depending on radio resources such as frequency, the calculation of calibration data is performed for each radio resource. In addition, since it varies depending on environmental conditions such as temperature, calibration data is calculated when the environmental conditions change by a certain value or more.
Japanese Patent Laid-Open No. 10-336149 JP 2004-153696 A

  However, since it is necessary to transmit and receive a calibration signal for each radio resource in order to calculate calibration data, it takes a considerable amount of time to complete the calculation of calibration data for all radio resources. During this time, there has been a problem that calibration data adapted to changes in environmental conditions cannot be used.

  Accordingly, one of the objects of the present invention is to provide a wireless communication apparatus and a transmission signal calibration method that can use calibration data adapted to changes in environmental conditions even if calculation of calibration data is not completed. .

  A wireless communication apparatus according to the present invention for solving the above-described problems includes a calculation unit that calculates calibration data, calibration data calculated by the calculation unit, and an environment at the time when the calibration data is calculated. Based on the calculation environment condition stored in the storage means and the current environment condition indicating the current environment from the storage means, Calibration data acquisition means for acquiring calibration data corresponding to the environment, and transmission signal calibration means for calibrating the transmission signal based on the calibration data acquired by the calibration data acquisition means, To do.

  According to this, even if the calculation of the calibration data is not completed, the calibration data corresponding to the current environment can be acquired based on the calibration data stored in the past. Calibration data adapted to changes can be used.

  Further, in the wireless communication apparatus, the calibration data acquisition unit may include calibration data corresponding to a current environment from calibration data stored in the storage unit in association with each of the plurality of environmental conditions for calculation. The calibration data may be acquired by calculating.

  According to this, for example, calibration data corresponding to the current environment can be acquired based on calibration data stored in the past by a linear interpolation method or the like.

  Further, in each of the wireless communication devices, the storage unit stores the calibration data for the two environmental conditions at the time of calculation, and the wireless communication device is configured to calculate the calibration data when the calculation unit calculates the calibration data. Updating means for updating the storage means with the calibration data calculated by the calculation means according to whether or not the environmental conditions are between two calculation-time environmental conditions stored in the storage means; It may be included.

  According to this, the calibration data stored in the storage unit can be updated, and the range of environmental conditions for calculation can be expanded.

  The transmission signal calibration method according to the present invention includes a calculation step for calculating calibration data, calibration data calculated in the calculation step, and a calculation-time environment indicating an environment when the calibration data is calculated. A calibration data acquisition step for acquiring calibration data corresponding to the current environment based on the calibration data stored in the storage means for storing the conditions in association with each other and the environmental conditions at the time of calculation, and the calibration data A transmission signal calibration step of calibrating the transmission signal based on the calibration data acquired in the acquisition step.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a system configuration of a base station apparatus 100 according to the present embodiment. Here, base station apparatus 100 having four antennas and four transmission / reception processing systems will be described as an example.

  Base station apparatus 100 is a computer including a CPU and a memory. The CPU is a processing unit for executing a program stored in the memory, performs processing for controlling each unit of the base station apparatus 100, and implements functions described later. The memory stores programs and data for carrying out the present embodiment. It also operates as a work memory for the CPU.

  Base station apparatus 100 functions as a wireless communication apparatus, and performs wireless communication with a mobile station apparatus (not shown) in a mobile communication system such as WiMAX (Worldwide interoperability for Microwave Access). Also, wired communication is performed with an exchange (not shown).

  As shown in FIG. 1, the base station apparatus 100 includes antennas 101 to 104, a transmission / reception changeover switch 105, a reception system module 110, a transmission system module 120, a modem unit 130, a control unit 140, a storage device 150, and a power supply unit 160. Consists of.

  The antennas 101 to 104 are all connected to the transmission / reception selector switch 105. The transmission / reception selector switch 105 is connected to the reception system module 110 and the transmission system module 120.

  The reception system module 110 is connected to the antennas 101 to 104 via the transmission / reception selector switch 105. The modem unit 130 is also connected. The reception system module 110 includes a low noise amplifier (LNA) 111, a down converter (D / C) 112, and an A (Analog) / D (Digital) converter (A / D) 113 for each of the antennas 101 to 104. Is done.

  The transmission system module 120 is also connected to the antennas 101 to 104 via the transmission / reception selector switch 105. The modem unit 130 is also connected. The transmission system module 120 includes a D (Digital) / A (Analog) converter (D / A) 123, an up converter (U / C) 122, and a power amplifier (PA) 121 for each of the antennas 101 to 104. Is done.

  The modem unit 130, the control unit 140, and the storage device 150 are connected to a common bus.

  Hereinafter, the function of each part which comprises the base station apparatus 100 is demonstrated.

  Each of the antennas 101 to 104 receives an incoming radio signal and outputs the received radio signal to the transmission / reception change-over switch 105, and transmits a signal input from the transmission / reception change-over switch 105 to the radio section.

  The transmission / reception change-over switch 105 performs switching control between transmission and reception by time division, and realizes time division duplex. During transmission, a signal input from the transmission system module 120 is output to the antennas 101 to 104. During reception, signals input from the antennas 101 to 104 are output to the reception system module 110.

  The low noise amplifier 111 amplifies the signal input from the corresponding antenna to the reception system module 110 with low noise, and outputs the amplified signal to the corresponding down converter 112. The down converter 112 converts the frequency of the signal input from the corresponding low noise amplifier 111 and outputs it to the corresponding A / D converter 113. The A / D converter 113 converts the signal input from the corresponding down converter 112 into a digital signal and outputs the digital signal to the modem unit 130.

  The D / A converter 123 converts the digital signal input from the modem unit 130 into an analog signal and outputs the analog signal to the corresponding up converter 122. The up-converter 122 converts the frequency of the signal input from the corresponding D / A converter 123 into a transmission frequency instructed from the control unit 140 described later, and outputs the transmission frequency to the corresponding power amplifier 121. The power amplifier 121 amplifies the signal input from the corresponding up converter 122 and outputs the amplified signal to the corresponding antenna via the transmission system module 120.

  The modem unit 130 includes a plurality of arithmetic units, and performs phase control by modulation / demodulation of transmission / reception data and digital signal processing.

  The processing of the modem unit 130 will be specifically described. First, at the time of signal reception, the modem unit 130 synthesizes the digital signals input from the respective A / D converters 113 so as to maximize the D (desired wave) / U (interfering wave) ratio, and further demodulates them. The received data is output to the control unit 140. Further, the reception intensity and phase at each antenna are acquired from the digital signal input from each A / D converter 113, and the transmission weight is calculated based on the acquired reception intensity and phase.

  Next, at the time of signal transmission, the modem unit 130 receives input of transmission data from the control unit 140 and modulates it to obtain a digital signal. Based on the transmission weight and calibration data (described later), the amplitude and phase of the digital signal are controlled for each antenna. That is, the antennas 101 to 104 are used as adaptive array antennas to realize beam forming and null forming, and calibrate digital signals based on calibration data in order to accurately perform beam forming and null forming. The modem unit 130 outputs the digital signal whose amplitude and phase are controlled in this way to each D / A converter 123.

  The control unit 140 includes a plurality of CPUs, and controls the base station apparatus 100 as a whole. Here, in particular, necessary parameters (including a transmission frequency) and timing are instructed to the modem unit 130, and reception data input from the modem unit 130 is processed. Also, the transmission data is acquired and output to the modem unit 130. Further, a calibration data calculation process described later is performed to calculate calibration data and output the calculated calibration data to the modem unit 130.

  The control unit 140 is also connected to a public line and performs wired communication with an exchange (not shown). That is, a part of transmission data is received from an exchange (not shown) and is output to the modem unit 130, and a part of reception data input from the modem unit 130 is output to the exchange (not shown).

  The storage device 150 stores various data. Here, in particular, the calibration data calculated by the calibration data calculation process is stored.

  The power supply unit 160 is supplied with power such as 100 V and supplies power to each unit of the base station apparatus 100.

  Hereinafter, the calibration data calculation process performed by the control unit 140 will be described in detail.

  As shown in FIG. 1, the control unit 140 functionally includes a calculation unit 141, a calibration data acquisition unit 142, and an update unit 143. Furthermore, the storage device 150 includes a storage area A151 and a storage area B152.

  The calculation unit 141 calculates calibration data. Specifically, calibration signal generation data is generated and output to the modem unit 130. At this time, the modem unit 130 is instructed to transmit only from a specific antenna (here, antenna 101) with a specific carrier (frequency), phase, and amplitude. The modem unit 130 and the transmission system module 120 generate a calibration signal having the specific frequency, phase, and amplitude based on the input calibration signal generation data, and output the calibration signal from the antenna 101.

  Antennas other than the antenna 101 receive the calibration signal thus transmitted. Calibration signals received by each antenna are transmitted to the modem unit 130. The calculation unit 141 calculates calibration data based on the calibration signal transmitted to the modem unit 130 and the generated calibration signal generation data.

  The calculation unit 141 calculates the calibration data as described above while changing the specific antenna that transmits the calibration signal from the antenna 101 to the antenna 104 and changing the specific carrier. Thus, the calculation unit 141 calculates calibration data for each combination of antenna and carrier, and stores it in the storage area A151.

  FIG. 2 is a diagram showing a current calibration data table stored in the storage area A151. As shown in the figure, the current calibration data table stores calibration data for each carrier (in the figure, calibration data for each antenna is collectively described as “data”). Yes.

  Note that the calculation unit 141 determines that the current environmental conditions indicating the current environment have changed by a predetermined amount or more from the previous one (if a temperature change of a certain level or more occurs, or transmission / reception data is significantly different between the antennas. If any abnormality such as a difference is detected) and the communication amount is not greater than the predetermined amount, the calibration data calculation process is performed. When the calculation unit 141 starts the calibration data calculation process, the calculation unit 141 deletes all data currently stored in the calibration data table.

  The calibration data acquisition unit 142 determines whether calibration data is currently stored in the calibration data table. If it is determined that the data is stored, the calibration data stored in association with the transmission frequency instructed for the transmission data is read and output to the modem unit 130. The modem unit 130 calibrates the transmission data based on the calibration data. As a result of the determination, the case where it is not stored will be described later.

  Here, the storage area B152 corresponds to the calibration data calculated by the calculation unit 141 and the calculation-time environmental condition (here, temperature) indicating the environment when the calibration data is calculated. A past calibration data table to be added and stored is stored.

  FIG. 3 is a diagram illustrating a past calibration data table. As shown in the figure, the past calibration data table stores calibration data for two environmental conditions at the time of calculation.

  The update unit 143 associates the calibration data currently stored in the calibration data table with the environmental conditions when the calibration data is calculated, and stores them in the past calibration data table. Specifically, the calculation unit according to whether or not the environmental condition when the calibration data is calculated by the calculation unit 141 is between two calculation-time environmental conditions stored in the past calibration data table. The past calibration data table is updated with the calibration data calculated in 141.

  More specifically, the update unit 143 determines that the environmental condition at the time when the calibration data is calculated based on the fact that the new calibration data is currently stored in the calibration table by the calculation unit 141 is the past calibration. It is determined whether or not there is between two environmental conditions for calculation stored in the storage data table. Then, the past calibration data table is not updated if it is between the two calculation-time environmental conditions, and if it is not between the two calculation-time environmental conditions, the calibration data calculated by the calculation unit 141 is used. Update the past calibration data table.

  More specifically, the update unit 143 stores, in the past calibration data table, the temperature indicated by the environmental conditions at the time of calculation of the calibration data written in the calibration data stored in the calibration data table. When the temperature indicated by each of the two calculation environmental conditions is lower than the lower one, the calibration data stored in association with the calculation environmental condition indicating the lower temperature is stored in the current calibration data table. It is updated with the calibration data stored in. Similarly, the temperature indicated by the environmental condition at the time of calculation of the calibration data written in the calibration data currently stored in the calibration data table is each of the two environmental conditions at the time of calculation stored by the past calibration data table. Calibration data stored in association with the calculated environmental condition indicating the higher temperature when the temperature is higher than the higher one of the temperatures indicated by the calibration data stored in the current calibration data table. Update.

  The updating of the calibration data by the updating unit 143 will be described again in more detail with reference to the processing flow.

  FIG. 4 is a diagram illustrating a processing flow related to a certain carrier in the base station apparatus 100. As shown in the figure, the base station apparatus 100 performs calibration calculation processing and stores the calculated calibration data in the storage area A151 (S1). Next, it is determined whether or not the current temperature is lower than the lower one of the temperatures stored in the storage area B152 (S2). If not, it is further determined whether or not the current temperature is higher than the higher (High) of the temperatures stored in the storage area B (S3). When determined to be low in S2 and determined to be high in S3, the base station apparatus 100 updates the calibration data in the storage area B152 with the calibration data in the storage area A151 (S4). On the other hand, when it is determined in S3 that it is not high, the process ends without performing the process of S4.

  Hereinafter, a case where the calibration data acquisition unit 142 determines that the data is not stored as a result of the determination will be described.

  When it is determined that the calibration data acquisition unit 142 is not stored as a result of the determination, the calibration data acquisition unit 142 is based on the calculation-time environmental condition stored in the past calibration data table and the current environmental condition indicating the current environment. Then, calibration data corresponding to the current environment is acquired from the past calibration data table.

  Specifically, the calibration data acquisition unit 142 calculates calibration data corresponding to the current environment from the calibration data stored in the past calibration data table in association with each of the plurality of calculation environmental conditions. As a result, calibration data is acquired.

  More specifically, the calibration data acquisition unit 142 calculates the environment between the two calculation time environmental conditions from the calibration data stored in the past calibration data table in association with each of the two calculation time environmental conditions. Calibration data corresponding to the condition is acquired by linear interpolation (linear approximation). The calibration data acquisition unit 142 calculates calibration data corresponding to the current environment by this linear interpolation.

  The calculation of calibration data by the calibration data acquisition unit 142 will be described in more detail again with reference to the processing flow.

  FIG. 5 is a diagram illustrating a processing flow of the base station apparatus 100. As shown in the figure, when starting data communication, the base station apparatus 100 first determines a carrier (transmission frequency) to be used (S11). Next, it is determined whether or not calibration data is stored in the storage area A151 in association with the determined transmission frequency (S12). If not stored, calibration data corresponding to the current environment is estimated from the calibration data stored in the storage area B152 (S13). The base station apparatus 100 uses the calibration data if the calibration data is stored in the storage area A151, and the calibration data estimated in S13 if the calibration data is not stored in the storage area B152. Communication is performed while performing calibration (S14).

  As described above, according to the base station apparatus 100, calibration data corresponding to the current environment is acquired based on calibration data stored in the past even if calculation of calibration data is not completed. Therefore, calibration data adapted to changes in environmental conditions can be used.

  Further, for example, calibration data corresponding to the current environment can be acquired based on calibration data stored in the past by a linear interpolation method or the like.

  Furthermore, the calibration data stored in the past calibration data table can be updated, and the range of environmental conditions at the time of calculation can be expanded.

It is a figure which shows the system configuration | structure and functional block of the base station apparatus concerning embodiment of this invention. It is a figure which shows the present calibration table concerning embodiment of this invention. It is a figure which shows the past calibration table concerning embodiment of this invention. It is a figure which shows the processing flow of the base station apparatus concerning embodiment of this invention. It is a figure which shows the processing flow of the base station apparatus concerning embodiment of this invention.

Explanation of symbols

  101, 102, 103, 104 Antenna, 100 Base station apparatus, 105 Transmission / reception changeover switch, 110 Reception system module, 111 Low noise amplifier, 112 Down converter, 113 A / D converter, 120 Transmission system module, 121 Power amplifier, 122 Up converter , 123 D / A converter, 130 modem unit, 140 control unit, 141 calculation unit, 142 calibration data acquisition unit, 143 update unit, 150 storage device, 151 storage area A, 152 storage area B, 160 power supply unit.

Claims (4)

Calculating means for calculating calibration data;
Storage means for storing the calibration data calculated by the calculation means and the calculation-time environmental condition indicating the environment when the calibration data is calculated;
Calibration data acquisition means for acquiring calibration data corresponding to the current environment from the storage means based on the environmental condition at the time of calculation stored in the storage means and the current environment condition indicating the current environment; ,
Transmission signal calibration means for calibrating the transmission signal based on the calibration data acquired by the calibration data acquisition means,
A wireless communication apparatus comprising: The wireless communication device according to claim 1,
The calibration data acquisition means calculates calibration data corresponding to the current environment from calibration data stored in the storage means in association with each of the plurality of environmental conditions for calculation. Get data,
A wireless communication apparatus. The wireless communication apparatus according to claim 1 or 2,
The storage means stores the calibration data for the two environmental conditions at the time of calculation,
The wireless communication device
The calibration calculated by the calculation unit according to whether or not the environmental condition when the calibration data is calculated by the calculation unit is between two calculation-time environmental conditions stored in the storage unit Updating means for updating the storage means with data;
Further including
A wireless communication apparatus. A calculation step for calculating calibration data;
Calibration data and calculation-time environment stored in storage means for storing the calibration data calculated in the calculation step and the calculation-time environmental condition indicating the environment when the calibration data is calculated in association with each other A calibration data acquisition step for acquiring calibration data corresponding to the current environment based on the conditions;
A transmission signal calibration step for calibrating a transmission signal based on the calibration data acquired in the calibration data acquisition step;
A transmission signal calibration method comprising:

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