JP4468268B2 - COMMUNICATION SYSTEM, COMMUNICATION DEVICE, COMMUNICATION CONTROL METHOD, AND COMMUNICATION CONTROL PROGRAM - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system capable of improving communication quality. <P>SOLUTION: The wireless communication system, wherein a plurality of communication apparatuses carry out wireless communication with one another, includes: a transmission means for transmitting a communication signal; a reception means for receiving the communication signal; a correction data calculation means for calculating correction data on the basis of the strength of the received communication signal; a correction data storage means for storing the correction data; and a correction means for correcting the communication signal received by the reception means on the basis of the correction data stored in the correction data storage means. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a communication system, a communication device, a communication control method, and a communication control program capable of correcting ripple characteristics in a baseband band.

In a wireless communication apparatus using an intermediate frequency such as a heterodyne system, it is necessary to use an IF filter in order to remove spurious out of the baseband. In high-speed digital wireless communication in recent years, the spread spectrum communication method has become mainstream, and in order to perform high-speed data communication, the spectrum component of the wireless signal is increased with an increase in the number of symbols, and amplitude components such as 16QAM and 64QAM are required. Multi-level modulation is required.
For this reason, the IF filter of the heterodyne radio communication device required in recent high-speed data communication is required to have a low ripple in a wide band.

A receiver is known in which a constant gain can be obtained over the entire reception frequency without being affected by aging or module replacement (for example, see Patent Document 1).
JP 2001-069022 A

  By the way, the IF filter used in a heterodyne radio communication device or the like has a characteristic of sharply attenuating the outside of the band, and thus has a characteristic that the Q (Quality factor) value of the filter circuit is high. For this reason, it is easy to have ripples in the band, and the ripple characteristics are likely to change due to temperature changes and input / output impedance changes. In heterodyne radio communication devices, the ripple characteristic of the IF filter largely affects the communication quality. Therefore, there is a problem that the communication quality deteriorates if the ripple is large. In addition, since the IF filter is often used in multiple stages, there are many factors that can change the characteristics such as temperature change, aging, and unit replacement, and it is difficult to predict the change in the ripple characteristics of the IF filter. There's a problem. Therefore, there arises a problem that the modulation accuracy of the radio signal is lowered and the communication quality is deteriorated.

  The present invention was made in view of such circumstances, and in a communication device using spread spectrum technology, a communication system capable of self-correcting in-band ripple of a baseband signal and improving communication quality, It is an object to provide a communication device, a communication control method, and a communication control program.

The present invention is a wireless communication system including a communication device on a transmission side and a communication device on a reception side, and the communication device on the transmission side transmits a frequency signal obtained by dividing a frequency band of a communication signal into a predetermined number. Each of which includes a transmitting means for transmitting , the receiving-side communication device receiving each of the frequency signals transmitted by the transmitting means, an average intensity of the frequency signal received by the receiving means, Correction data calculation means for calculating correction data corresponding to each frequency from the difference from the intensity of the frequency signal, a frequency signal in the communication signal received by the receiving means, and the correction data corresponding to the frequency signal. and a correcting means for correcting the communication signals by adding, in between the transmitting communication apparatus and the reception side communication apparatus, each of the frequency Comprising a transmitting means for transmitting a signal and the transmission timing, the correction data calculating means, based on each of the frequency signal and the transmission timing, and performs calculation of the correction data.

The communication device according to the present invention includes a receiving unit that receives each frequency signal transmitted by the transmitting unit, and a difference between an average intensity of the frequency signal received by the receiving unit and a strength of each of the frequency signals. Correction data calculating means for calculating correction data corresponding to the frequency, and correcting the communication signal by adding the frequency signal in the communication signal received by the receiving means and the correction data corresponding to the frequency signal. and correcting means for, characterized by comprising a.

The present invention is a communication control method for performing wireless communication between a communication device on a transmission side and a communication device on a reception side, and the frequency signal obtained by dividing the frequency band of communication signals into a predetermined number by the communication device on the transmission side Each of the transmitting step, the receiving side communication device receiving the frequency signal transmitted in the transmitting step, and the receiving side communication device receiving the frequency signal received in the receiving step . A correction data calculation step for calculating correction data corresponding to each frequency from the difference between the average intensity and the intensity of each frequency signal, and the frequency in the communication signal received by the reception side communication device in the reception step includes a step of correcting said communication signal by adding the said correction data corresponding signal to the frequency signal, wherein the transmission A transmission step for transmitting the frequency signal and transmission timing between the communication device and the communication device on the receiving side, and the correction data calculation step includes the frequency signal and the transmission timing. Based on this, the correction data is calculated .

The present invention is a communication control program for causing a computer mounted on a communication device on the transmission side and a computer mounted on the communication device on the reception side to perform wireless communication, wherein the communication device on the transmission side divides the frequency band of communication signals into a predetermined number. A transmission step for transmitting the frequency signals obtained in the above, a reception step for receiving the frequency signal transmitted by the reception side communication device by the transmission step, and a reception step for receiving the frequency signal transmitted by the reception side communication device. Correction data calculating step for calculating correction data corresponding to each frequency from the difference between the average intensity of the frequency signal and the intensity of each of the frequency signals, and the receiving side communication device received by the receiving step to correct the communication signal by adding the frequency signals in the communication signal and the correction data corresponding to the frequency signal A correction step, wherein the in between the transmitting communication apparatus and the reception side communication apparatus has a transmission step of transmitting each of the frequency signal and the transmission timing, the correction data calculating step The computer is caused to perform a process of calculating the correction data based on each frequency signal and transmission timing .

  According to the present invention, it is possible to prevent deterioration in communication quality by performing self-correction of ripples in the baseband due to aging, temperature change, and the like. In addition, since the characteristic measurement and correction are performed autonomously, the ripple characteristic can be corrected without using a special measuring instrument, so that the communication quality can be prevented from deteriorating without increasing the cost. The effect is obtained.

  Hereinafter, a communication system according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment. In this figure, reference symbols A and B denote heterodyne transmission / reception duplex wireless communication devices (hereinafter referred to as wireless stations). The radio stations A and B have the same configuration, for example, the radio station A is a base station, and the radio station B is a mobile terminal (mobile station). Although the two radio stations A and B shown in FIG. 1 have the same configuration, different reference numerals are given to make it easy to understand which of the two radio stations is. Here, only the configuration of the wireless station A will be described, and a detailed description of the configuration of the wireless station B having the same configuration as the wireless station A will be omitted.

  Reference numeral 10 denotes a transmission unit that transmits a communication signal through the antenna 19 and includes an IF filter therein. Reference numeral 11 denotes a receiving unit that receives a communication signal via the antenna 19 and includes an IF filter therein. Reference numeral 12 denotes a frequency sweep unit that sweeps the transmission frequency of the transmission unit 10 and the reception frequency of the reception unit 11. Reference numeral 13 denotes a signal processing unit that performs signal processing of a communication signal to be transmitted and a received communication signal. Reference numeral 14 denotes an application execution unit that executes an application, and performs generation of communication data to be transmitted, reproduction of received communication data, and the like.

  Reference numeral 15 denotes a correction value calculation unit that calculates a correction value for correcting the ripple characteristic in the baseband. Reference numeral 16 denotes a storage unit that stores the correction value calculated by the correction value calculation unit 15 and stores the strength information of the communication signal received by the reception unit 11. Reference numeral 17 denotes a correction processing unit that corrects the communication signal received by the reception unit 11 based on the strength information of the communication signal stored in the storage unit 16. Reference numeral 18 denotes a correction execution transmission unit that communicates with the wireless station B the acquisition timing of the intensity information of the communication signal stored in the storage unit 16 and the frequency information swept by the frequency sweep unit 12.

  Next, operations of the radio stations A and B shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a flowchart showing an operation of measuring and storing the fluctuation of the reception level (reception strength) of the communication signal in the wireless station B. First, the user of the wireless station B performs an operation of starting correction value update processing from an input unit (not shown). In response to this, the correction execution transmission unit 28 uses the wireless line currently communicating via the transmission unit 20 to send information (frequency to be used and transmission timing) of the frequency sweep method to the wireless station A. Send. Information about this frequency sweep method is received by the correction execution transmission unit 18 via the reception unit 11.

  The correction execution transmission unit 18 sets the frequency and transmission timing used for the sweep to the frequency sweep unit 12 based on the received information on the frequency sweep method. Further, the correction execution transmission unit 28 sets the frequency used for the sweep and the reception timing for the frequency sweep unit 22 based on the information on the frequency sweep method transmitted to the wireless station A. (Step S1). In this way, the radio station A sweeps the transmission frequency while synchronizing based on the predetermined frequency sweep method, and the radio station B starts an operation of sweeping the reception frequency in synchronization with the transmission frequency sweep of the radio station A. Thereby, the acquisition process of the ripple characteristic correction data of the IF filter is started (step S2).

  The two frequency sweeping units 12 and 22 set internal parameters based on the frequency sweeping method decided in advance (step S3). Here, it is assumed that the baseband signal center frequency is Fbc, the baseband bandwidth is Fw, the baseband bandwidth sweep step is N, the sweep counter A is reset to 0, and the RF local frequency is set to Flo.

  Next, the frequency sweep unit 12 increments the value of the sweep counter A (step S4), and obtains the frequency (Fc− (Fw / 2) + (A × (Fw / N))). Then, the transmission unit 10 is notified of the obtained frequency. Receiving this, the transmission part 10 performs CW (Continuous Wave) transmission with the frequency notified within the transmission baseband band (step S5). At this time, the transmission local frequency of the wireless station A and the reception local frequency of the wireless station B remain fixed (step S6). On the other hand, the frequency sweep unit 22 of the radio station B changes the reception frequency based on the frequency sweep method information decided with the radio station A, and receives the communication signal reception level every time the transmission baseband CW frequency is changed. Is stored in the storage unit 26 (step S7).

  The processing operations in steps S4 to S7 are repeated until the value of the sweep counter A reaches the baseband bandwidth sweep step N (step S8). Thus, every time the transmission baseband CW frequency of the wireless station A is changed, the received fluctuation data of the reception level at the wireless station B is stored in the storage unit 26. This fluctuation data is a ripple characteristic in a state where the IF filters of both stations (wireless stations A and B) are combined (the combined characteristic of the ripple in the transmission baseband of the wireless station A and the ripple in the reception baseband of the wireless station B) ) Data (steps S9 and S10).

  If the wireless station is a mobile station, the processing operation shown in FIG. 2 may be started when the power is turned on, the timing notified from the base station, or the time and date determined in advance. Good. Further, when the wireless station is a base station, it may be started at a predetermined time or when an instruction is received by remote operation.

  Next, an operation in which the correction value calculation unit 25 shown in FIG. 1 calculates a correction value will be described with reference to FIG. FIG. 3 is a flowchart illustrating an operation in which the correction value calculation unit 25 illustrated in FIG. 1 calculates a correction value. First, the correction value calculation unit 25 reads the data of the reception level (reception strength) stored in the storage unit 26, and calculates the average value Rlvm of the reception level (step S21). Next, the correction value calculation unit 25 subtracts the value of the reception level at the frequency fbn from the calculated average value Rlvm to obtain the correction value Sdn of the frequency fbn (step S22). Then, the correction value calculation unit 25 stores the calculated correction value Sdn in the storage unit 26 in association with the frequency fbn (step S23). The correction value calculation unit 25 determines whether or not processing has been performed for all the frequencies fbn (steps S24 and S25), and stores the correction value Sdn for all the frequencies fbn in the storage unit 26 for the processing of steps S22 and S23. Repeat until Accordingly, the correction value Sdn is calculated for the frequency fbn in the storage unit 26, and the correction value Sdn is stored in the storage unit 26 in association with the frequency fbn.

  Next, with reference to FIG. 4, the operation | movement which correct | amends the communication signal which the correction process part 17 shown in FIG. 1 received is demonstrated. FIG. 4 is a flowchart showing an operation of correcting the communication signal received by the correction processing unit 17 shown in FIG. First, the correction processing unit 27 detects the reception baseband frequency fbn of the communication signal received by the reception unit 21 (step S31). Next, the correction processing unit 27 reads out and acquires the correction value Sdn corresponding to the detected reception baseband frequency fbn from the storage unit 26 (step S32). Then, the correction processing unit 27 adds the read correction value Sdn to the reception level (reception strength) Rlv of the communication signal received by the reception unit 21 to obtain the corrected reception level Rlvs (step S33). By this correction operation, the reception level (reception intensity) of the communication signal received by the receiving unit 21 is corrected by the latest correction value, so that the communication quality can be improved.

  In the above description, the bidirectional communication between the wireless stations A and B has been described as an example. However, the communication may be applied to a communication system for unidirectional communication from the wireless station A to the wireless station B. In addition, if either one or both of the radio stations A and B is a heterodyne radio communication device, the effect is great. However, it is not always necessary to use a heterodyne radio communication device, and the frequency level deviation is not necessarily within the baseband band. Can be applied and a similar effect can be obtained. Furthermore, it can be applied to broadband spread spectrum communication such as optical communication and transmission path communication regardless of radio.

As described above, the self-correction of the ripple in the baseband due to the secular change and the temperature change after the product shipment can prevent the communication quality from being deteriorated. In addition, since the characteristics are measured and corrected autonomously, the ripple characteristics can be corrected without using a special measuring instrument, and correction processing can be performed by remote control in a base station or the like. Therefore, it is possible to prevent the communication quality from deteriorating without increasing the management cost.
In addition, the transmission baseband in-band ripple characteristics and the reception baseband in-band ripple characteristics can be corrected simultaneously at the same time. High baseband in-band ripple correction is possible.

  The wireless communication terminal (mobile terminal) of the present invention includes a mobile phone using mobile communication, a personal digital assistant (PDA) having a mobile communication function, a mobile terminal, a car navigation device, and the like.

  The program for realizing the function of the processing unit in FIG. 1 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into the computer system and executed to execute a ripple characteristic correction process. May be performed. The “computer system” here includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

It is a block diagram which shows the structure of one Embodiment of this invention. 2 is a flowchart showing the operation of the radio station shown in FIG. 2 is a flowchart showing the operation of the radio station shown in FIG. 2 is a flowchart showing the operation of the radio station shown in FIG.

Explanation of symbols

10, 20 ... Transmitter, 11, 21 ... Receiver, 12, 22 ... Frequency sweep, 13, 23 ... Signal processor, 14, 24 ... Application execution unit, 15, 25... Correction value calculation unit, 16, 26... Storage unit, 17, 27... Correction processing unit, 18, 28.

Claims (4)

A wireless communication system comprising a communication device on the transmission side and a communication device on the reception side ,
The transmitting side communication device is:
A transmission means for transmitting each frequency signal obtained by dividing the frequency band of the communication signal into a predetermined number ;
The receiving side communication device is:
Receiving means for receiving each of the frequency signals transmitted by the transmitting means;
Correction data calculating means for calculating correction data corresponding to each frequency from the difference between the average intensity of the frequency signal received by the receiving means and the intensity of each of the frequency signals ;
Correction means for correcting the communication signal by adding the frequency signal in the communication signal received by the receiving means and the correction data corresponding to the frequency signal ,
Between the transmission-side communication device and the reception-side communication device, comprising a transmission means for transmitting each of the frequency signals and transmission timing,
The correction data calculation means calculates the correction data based on each frequency signal and transmission timing . Receiving means for receiving each of the frequency signals transmitted by the transmitting means;
Correction data calculating means for calculating correction data corresponding to each frequency from the difference between the average intensity of the frequency signal received by the receiving means and the intensity of each of the frequency signals ;
Correction means for correcting the communication signal by adding the frequency signal in the communication signal received by the receiving means and the correction data corresponding to the frequency signal ;
A communication device characterized by comprising: A communication control method for performing wireless communication with a communication device on a transmission side and a communication device on a reception side ,
A transmitting step in which each of the transmitters transmits a frequency signal obtained by dividing a frequency band of a communication signal into a predetermined number ;
A receiving step in which each of the receiving side communication devices receives the frequency signal transmitted in the transmitting step ;
A correction data calculating step for calculating correction data corresponding to each frequency from the difference between the average intensity of the frequency signal received by the receiving step and the intensity of each of the frequency signals ;
A correction step of correcting the communication signal by adding the frequency signal in the communication signal received by the reception side communication device in the reception step and the correction data corresponding to the frequency signal ;
Have
A transmission step of transmitting the frequency signal and the transmission timing between the transmission-side communication device and the reception-side communication device;
The communication control method characterized in that the correction data calculation step calculates the correction data based on each frequency signal and transmission timing . A communication control program for causing a computer mounted in a communication device on a transmission side and a communication device on a reception side to perform wireless communication,
A transmitting step in which each of the transmitters transmits a frequency signal obtained by dividing a frequency band of a communication signal into a predetermined number ;
A receiving step in which each of the receiving side communication devices receives the frequency signal transmitted in the transmitting step ;
A correction data calculating step for calculating correction data corresponding to each frequency from the difference between the average intensity of the frequency signal received by the receiving step and the intensity of each of the frequency signals ;
A correction step of correcting the communication signal by adding the frequency signal in the communication signal received by the reception side communication device in the reception step and the correction data corresponding to the frequency signal ;
Have
A transmission step of transmitting the frequency signal and the transmission timing between the transmission-side communication device and the reception-side communication device;
The correction data calculation step causes a computer to perform a process of calculating the correction data based on each frequency signal and transmission timing .

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