JP2007295532A - Wireless communication system, and error measurement and error determining method of wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excellent method of using a reception electric field intensity and a measurement of a bit error rate for measuring a line quality in order to receive a wireless carrier from a base station in an optimum state and to periodically maintain and manage a system in a digital wireless communication system. <P>SOLUTION: A wireless communication system has a first base station, and a plurality of mobile stations receiving a signal transmitted by a wireless line from the first base station. The first base station has a signal processor, and transmits a transmission signal to which an error detecting code is added in the signal processor to the mobile stations. The mobile stations have a reception signal processor which processes the transmission signal to which the error detecting code is added. The reception signal processor has a means correcting an error of the transmission signal, a means reproducing an output of the error correcting means, and a comparison means comparing the transmission signal with the output of the error correcting means. A bit error rate is outputted from the comparison means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio communication system and an error measurement and error determination method for a radio communication system, and more particularly, to a radio communication system and a radio communication system that enable error measurement and error determination of a radio channel using a transmitted data signal. The present invention relates to an error measurement and error determination method.

  One of the digital radio communication systems in practical use is the SCPC (Single Channel Per Carrier) digital radio communication system defined by the standard ARIB STD-T61 (Association of Radio Industries and Businesses-T61). . The SCPC digital wireless communication system will be described with reference to FIGS. This SCPC digital wireless communication system is a relatively simple system based on simplex-type press talk communication, in which one wireless carrier corresponds to one communication channel, and calls using one communication channel per base station. Service is fundamental. This system includes a control device (also referred to as a control station) 701, a radio base station (or simply referred to as a base station) 702-1, 702-2, ... 702-M (in the case of representing a base station, ), Communication areas 703-1, 703-2,... 703-M of each base station 702 (referred to as communication area 703 when representing a communication area), mobile station 704-. 1, 704-2,... 704-N (in the case of representing a mobile station, it is referred to as a mobile station 704), a transmission path 705, and a wired terminal station 706. A communication connection service for direct communication between a plurality of mobile stations 704 in the communication area 703 of the base station 702 and the base station 702, or between mobile stations via the base station, or between the mobile stations, or outside the communication area 703 This is a system configured to provide a communication connection service between the mobile station 704-3 and the mobile station 704-2 in the communication area 703-1. The mobile station 704 is a wireless terminal station, and includes a portable wireless device, an in-vehicle wireless device, and the like.

  The control device 701 is connected to each base station 702 via a transmission line 705, and performs communication connection and service area maintenance and management among the base station 702, the wired terminal station 706, and the plurality of mobile stations 704 in the digital wireless communication system. The control device 701 is provided with a line control device, and performs control for making a call control from the mobile station 704 and the wired terminal station 706 or setting a communication route. It also manages connection services between multiple base stations. 7 shows a case where the control device 701 is separated from the base station 702, for example, the control device 701 may be integrated with the base station 702-1.

  Thus, for example, FIG. 8 shows radio carrier frequency allocation permitted to be used in a digital radio communication system using the digital radio technology defined by the standard ARIB STD-T61. In FIG. 8, in the uplink direction, that is, in the direction from the mobile station to the base station, a radio carrier f of about 367 MHz to 369 MHz and a radio carrier f1, f2, f3,. Further, in the downstream direction, that is, in the direction from the base station to the mobile station, the wireless carrier F of about 385 MHz to 387 MHz, which is 18 MHz away from the upstream direction of 367 MHz, has a width of 6.25 KHz, and the wireless carriers F1, F2, F3. Is allowed. Therefore, in the communication of the digital wireless system, the frequencies in the upstream direction f1, f2,..., The downstream directions F1, F2,.

  For example, the downlink communication channel between the base station 702-1 and the mobile station 704-1 is a frequency F1, and the uplink communication channel from the mobile station 704-1 to the base station 702-1 is a pair wave of the frequency f1. Is used. Further, in the direct communication between mobile stations between the mobile station 704-3 outside the communication area 703-1 and the mobile station 704-2 within the communication area 703-1, one of the radio carriers W1 of the radio carriers W1 One wave is allowed.

  When communication is performed in the digital wireless system of FIG. 7, communication is started. For example, the base station side turns on the press switch and simultaneously transmits SB0 (Synchronous Burst 0) several times to synchronize with the communication receiving side. After the establishment, a voice call is performed by SC (Service Channel). The transmission frame structure of this signal is shown in FIG. In FIG. 9, the synchronization burst SB0 for synchronization is transmitted three times, SB01, SB02, and SB03, and then the communication channel SC is sequentially transmitted in the order of SC1, SC2,. One section of SB0 and SC is about 40 ms as shown in FIG.

  The signal formats of SC and SB0 are as shown in FIG. In FIG. 10, LP + R is a linearizer preamble and burst transient response guard time, Pa and Pb are preambles, TCH is a traffic channel, RI is a radio information channel, SW is a synchronization word, and PI is a parameter information channel. , G is a guard time. The number represents the number of bits.

  The communication channel SC is a bidirectional channel used by a user to transmit information such as voice and data, and is a traffic channel (TCH: Traffic Channel) and a radio information channel (RICH: Radio Information Channel, in FIG. 10). Indicated by RI). The synchronization burst SB0 is burst data for synchronization exchanged before the communication channel SC at the time of communication on the assigned radio channel.

  Thus, in such a digital wireless communication system, in general, a route to a base station where the mobile station is located is selected so that a call can be made even if the mobile station moves to another base station zone. It has a tracking connection function for connecting lines, and a location registration function for sending a location registration signal from the terminal station to the base station when the base station zone in the area changes.

  That is, in this digital radio communication system, the mobile station performs control of standby and location registration. First, the mobile station 704 scans the radio channel transmitted by the base station 702, and obtains control information necessary for call connection by receiving the radio channel with the highest reception level. If the base station information included in the control information is different from the base station information stored in the mobile station, the mobile station location registration is performed by sending its mobile station number to the control device 701 via the base station. I do.

  In addition, subsequently, the mobile station receives a paging channel for informing control information used for calling the mobile station at the time of incoming call, and waits for an incoming call. In addition, the mobile station activates the peripheral zone monitoring mode when the received signal from the base station deteriorates for a certain time with respect to the channel switching level specified by the radio channel of the base station, and the peripheral base stations Receive a radio channel to transmit. At this time, if there is a base station with a higher reception level than the base station that has already registered the location information, by newly registering the location information, an incoming call is received in the area of the base station with a higher reception level. Wait. On the other hand, when a base station above a specified level is not found in the peripheral zone monitoring mode, the monitoring mode is continued at the same time as out-of-service display.

  Accordingly, the mobile station is required to constantly monitor the radio carrier from the base station so as to receive it in an optimum state, and to secure a so-called base station area with a higher reception level and a good channel quality. In addition, this digital radio communication system periodically measures the line quality for system maintenance, and is associated with the influence of fading, multipath, etc., or with the aging of the components constituting the radio communication system. Maintenance, inspection, replacement, etc. are also performed.

  In such a digital radio communication system, the base station and the mobile station always monitor the synchronization burst SB0 and the communication channel SC, and reproduce and synchronize the transmission side timing necessary to extract the required data from the received signal. Is required.

  Further, in order to reliably receive the data on the transmission side, it is necessary for the wireless device on the reception side to maintain the state of the wireless line in a higher quality state. In particular, in a wireless system in which a wireless device is moved by a vehicle or the like, the quality of the wireless line is constantly changing due to the influence of surrounding terrain and noise, resulting in a poor state. Requires a means for detecting the line quality in the radio apparatus on the receiving side.

  As a method for determining the quality of the radio channel quality, there is a method of using a received signal strength indicator (RSSI) or a bit error rate (BER) of a radio carrier transmitted by a base station. The most dominant RSSI is used for the radio channel quality. However, the received electric field strength RSSI of the wireless carrier is BER, although the received electric field strength is sufficiently large due to the influence of multipath due to the topography and the building, the same wave interference by other stations transmitting at the same frequency, etc. It is known that there are cases where the original transmission data cannot be restored due to an increase in size.

  In particular, in a wireless communication system in which a terminal station is moved by a vehicle or the like, the original data cannot be restored at all due to the large BER despite the sufficient received electric field strength due to the surrounding environment of the stop location Therefore, it is a factor that reduces the reliability of the wireless communication system.

  The present invention provides a method for measuring the bit error rate BER, and provides a more reliable radio communication system by warning the channel quality using the obtained BER. Further, as will be described later, an error determination is made as to whether or not the received data is correct, and a wireless communication system with higher reliability is provided.

Now, the measurement method of the bit error rate BER in the conventional digital radio communication system has the following problems. That is,
(1) In order to calculate the bit error rate of the radio channel, a method is used in which a predetermined data pattern is transmitted from the base station, the transmission data is compared with the transmission data, and the number of mismatches is counted. However, in order to transmit this data pattern, it is necessary to change the base station to a dedicated mode for bit error rate measurement, or it is necessary to occupy the communication channel and transmit the data pattern. There is an inconvenience that the area test and the bit error rate BER cannot be measured while providing a normal service.

  (2) In addition, in order to measure the bit error rate BER in a normal operation state, it is necessary to include a known data string common to each frame. However, since the data frame transmitted by the base station differs for each functional channel as shown in FIG. 10, the area that can be used as known data in common with each frame is the synchronization word in the SC frame configuration shown in FIG. 20 bits corresponding to SW. In calculating the error rate BER using 20 bits of the synchronization word SW, the BER cannot be measured with high accuracy because the number of bits is small.

Not particularly found.

  In this digital wireless communication system, a radio carrier from a base station is received in an optimal state, and measurement of a bit error rate is used for measurement of channel quality for regular system maintenance. But there is no good way.

  An object of the present invention is to provide a wireless communication system and an error measurement and error determination method for a wireless communication system that can perform error measurement and error determination by a simple method.

  Another object of the present invention is to provide a wireless communication system and an error measurement and error determination method for a wireless communication system that can perform error measurement and error determination in an operating state of the system.

  Another object of the present invention is to provide a radio communication system capable of highly accurate error measurement and error determination and an error measurement and error determination method for the radio communication system.

  Another object of the present invention is to provide a wireless communication system capable of measuring an error and determining an error without setting a special mode such as connection of a special external device to the base station or a maintenance mode, and an error measurement and error of the wireless communication system. It is to provide a determination method.

  Another object of the present invention is to provide a radio communication system and an error rate measurement method for a radio communication system that can issue a warning of quality degradation of a radio channel using the calculated bit error rate.

  Still another object of the present invention is to provide a radio communication system and a radio communication system error determination method with higher reliability by determining whether received data is correct.

  The wireless communication system of the present invention includes a first base station and a plurality of mobile stations that receive signals transmitted from the first base station through a wireless channel, and the first base station performs signal processing. And transmitting a transmission signal to which the error detection code is added by the signal processing unit to the mobile station, and the mobile station includes a reception signal processing unit for processing the transmission signal to which the error detection code is added. The received signal processing unit comprises: means for correcting the error of the transmission signal; means for reproducing the output of the means for correcting error; and comparing means for comparing the output of the transmission signal and the means for correcting error And the bit error rate is output from the comparison means.

  In the wireless communication system of the present invention, the first base station further includes a second base station, and one of the mobile stations is calculated from a transmission signal to which the error detection code from the first base station is added. When the bit error rate of the second base station is equal to or greater than a predetermined value, the mobile station calculates a second bit error rate from the transmission signal to which the error detection code is added from the second base station, and the second bit If the error rate is less than or equal to a predetermined value, the mobile station is configured to change location registration to the second base station.

  The present invention also includes a first base station and a plurality of mobile stations that receive signals transmitted from the first base station through a radio channel, and the first base station includes a signal processing unit. And transmitting a transmission signal to which the error detection code is added by the signal processing unit to the mobile station, the mobile station having a reception signal processing unit for processing the transmission signal to which the error detection code is added In the communication system, the received signal processing unit of the mobile station performs error correction of the transmission signal to which the error detection code is added, compares the error-corrected signal with the signal before error correction, and performs bit error. Configured to output rate.

  The present invention also includes a first base station and a plurality of mobile stations that receive signals transmitted from the first base station through a radio channel, and the first base station includes a signal processing unit. And transmitting the transmission signal to which the error detection code is added by the signal processing unit to the mobile station, and the mobile station has a reception signal processing unit for processing the transmission signal to which the error detection code is added. The received signal processing unit performs error correction by the error correcting unit of the mobile station in a wireless communication system having an error correcting unit and an arithmetic unit for calculating an output of the error correcting unit, and The arithmetic unit is configured to determine whether or not error correction is correct, and to control signal reproduction based on the determination result.

  The present invention also includes a first base station and a plurality of mobile stations that receive signals transmitted from the first base station through a radio channel, and the first base station includes a signal processing unit. And transmitting a transmission signal to which the error detection code is added by the signal processing unit to the mobile station, the mobile station having a reception signal processing unit for processing the transmission signal to which the error detection code is added In the communication system, the received signal processing unit of the mobile station performs error correction of the transmission signal to which the error detection code is added, and also receives the reception information P ′ (X) of the error-corrected received data as an error detection code G. An error determination is made based on the presence / absence of a remainder divided by (X).

  As described above, the present invention realizes a wireless communication system capable of measuring and judging errors by a simple method using user data such as voice and data in a communication channel transmitted from a base station. can do. In addition, because error measurement and error determination are possible in the system operating status, there is no need to stop the system for error measurement and error determination, and there is a special connection to the base station such as special external devices and maintenance mode. It is possible to realize a radio communication system and an error measurement and error determination method for a radio communication system that can perform error measurement and error determination without setting a simple mode.

  An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a base station 702 used in the present invention, and FIG. 2 is a block diagram showing a schematic configuration of a mobile station 704. The base station shown in FIG. 1 corresponds to the base station 702 shown in FIG. 7, and the mobile station shown in FIG. 2 corresponds to the mobile station 704 shown in FIG. In this embodiment, the configuration of the digital radio communication system is almost the same as that of the system shown in FIG. In the present invention, the SCPC digital radio communication system will be described. However, the present invention is not limited to the SCPC digital radio communication system, and it goes without saying that the present invention can be applied to an FDMA digital radio communication system and a general digital radio communication system. .

  In FIG. 1, the base station 702 includes a signal processing device 101 and a wireless device 102. The terminal 103 is a connection terminal connected to the control device 701. The signal processing device 101 includes a signal processing unit 104, a storage unit 105, and an operation console 106, and has a function of managing a wireless communication system. The wireless device 102 includes a transmitting wireless device 107 and a receiving wireless device 108. As described above, the transmission radio 107 transmits the signal from the signal processing apparatus 101 to the mobile station 704 using, for example, the downlink radio carrier F1. On the other hand, the receiving radio unit 108 receives a signal transmitted from the mobile station 704 using, for example, the uplink radio carrier f1. That is, transmission / reception is performed using a pair wave of F1 and f1. The console 106 includes an operation unit, a microphone, a speaker, and the like.

  FIG. 2 is a block diagram showing a schematic configuration of the mobile station 704. Note that the mobile station 704 shown in FIG. 2 is a wireless communication apparatus that can transmit and receive, for example, a paired wave of the downlink radio carrier F1 and the uplink radio carrier f1. In FIG. 2, 201 is an antenna for performing transmission / reception with the radio apparatus 102 of the base station 702, 202 is a changeover switch for switching transmission / reception, 203 is a reception unit, 204 is a reception signal processing unit, and 205 is a speaker. 206 is a control unit, 207 is a storage unit, 208 is a display unit, 209 is an operation unit, 210 is a microphone, 211 is a transmission signal processing unit, and 212 is a transmission unit.

  For the operation of the mobile station, first, the operation unit 209 is operated, for example, the mobile station number of the other party is input with the numeric keypad, and the call button is pressed. Since the transmission state is established when the other party leaves, the audio signal input from the microphone 210 is input to the transmission unit 212 after being subjected to predetermined signal processing for transmission by the transmission signal processing unit 211. The signal input to the transmission unit 212 is subjected to predetermined modulation for transmission, converted to a predetermined transmission frequency f1, output from the antenna 201 via the changeover switch 202, and received by the radio apparatus 102 of the base station 702. Is transmitted to the wireless device 108.

  On the other hand, a signal from the transmitting radio 107 of the radio apparatus 102 of the base station 702 is received by the antenna 201 and input to the receiving unit 203 via the changeover switch 202. The signal input to the reception unit 203 is amplified at a high frequency, converted to a predetermined intermediate frequency, further demodulated, and supplied to the reception signal processing unit 204. The reception signal processing unit 204 outputs a sound signal from the speaker 205 after predetermined signal processing, and displays data on the display unit 208 in the case of data.

Next, the operation of the digital wireless communication system described above will be described with reference to FIG. In FIG. 6, for example, the mobile station 704-5 is moving in the communication area 703-1 of the base station 702-1, and base station information is transmitted from the base station 702-1 to the mobile station 704-5. It is assumed (step 601). In this state, the mobile station 704-5 constantly monitors the reception level. As the reception level in this case, a bit error rate BER described later is measured, and it is monitored whether the bit error rate BER is equal to or lower than a predetermined level TH (step 602). If the bit error rate BER is equal to or lower than the predetermined level TH (Yes), the process proceeds to step 603 to hold the standby state. However, if the bit error rate BER is equal to or higher than a predetermined level TH (No because it is not below), the process proceeds to step 604, and the peripheral zone monitoring mode is entered. Then, the bit error rate BER in the communication area of the surrounding base station is measured (step 605). The bit error rate BER is a predetermined level TH, for example, 3 × 10 ⁻² , but it goes without saying that the bit error rate BER is appropriately set depending on the system configuration or the like. If the bit error rate BER is equal to or higher than the predetermined level TH, it means that correct voice and data cannot be reproduced.

  In step 605, the bit error rate BER of the communication area 703-2 of the neighboring base station, for example, the base station 702-2, is measured. As a result of the measurement, if the bit error rate BER of the communication area 703-2 of the base station 702-2 is equal to or higher than a predetermined level TH (below, it is not below), the process proceeds to step 606, where out-of-service processing is performed. That is, since no base station can communicate, for example, “out of service area” is displayed on the mobile station 704-5. If the bit error rate BER of the communication area 703-2 of the base station 702-2 is equal to or lower than a predetermined level TH (Yes), the mobile station 704-5 transmits a location registration request to the base station 702-2. (Step 607). Receiving the location registration request from the mobile station 704-5, the base station 702-2 transmits the location registration request to the control device 701 (step 608).

  When receiving the location registration request from the base station 702-2, the control device 701 performs an authentication process with the base station 702-2 (step 609). That is, the mobile station 704-5 is authenticated by, for example, an ID, and when authentication is established, the control device 701 transmits a location registration completion notification to the base station 702-2 (step 610). Receiving the location registration completion notification, the base station 702-2 transmits a location registration completion notification to the mobile station 704-5 (step 611). As a result, the mobile station 704-5 can communicate within the communication area 703-2 of the base station 702-2, and the process proceeds to step 612. That is, the mobile station 704-5 enters a standby state in a state where it can communicate with the base station 702-2.

  Now, as described above, when the mobile station 704 moves within the communication area of the base station 702, it is necessary to constantly monitor the communication level to determine whether communication is possible. In this embodiment, the bit error rate BER Is measured and this is judged.

  In addition, as described above, the digital wireless communication system periodically measures the line quality for system maintenance, and configures the presence or absence of fading or multipath effects or the wireless communication system. Maintenance, inspection, replacement, etc. associated with aging of the parts to be performed are also performed, and the bit error rate BER is also measured for this purpose. Hereinafter, a method for measuring the bit error rate BER in the present embodiment will be described in detail with reference to FIGS.

  The basic idea of the present invention is that, in a digital wireless communication system, an arbitrary bit string of user data such as a voice signal or a data signal in a data frame transmitted during a call is used, and a bit string before error correction and error correction. The bit error rate can be measured with high accuracy by comparing with the subsequent bit string.

  First, the frame configuration used in the present embodiment is as shown in FIG. 10 described in the conventional digital wireless communication system. It is assumed that user data such as a voice signal and a data signal is transmitted on the traffic channel TCH of the communication channel SC. Note that an audio signal, a data signal, or the like is referred to as a transmission signal. FIG. 3 is a block diagram illustrating a schematic configuration of the signal processing unit 104 of the signal processing device 101 of the base station 702. In FIG. 3, for example, a transmission signal (sound or data signal or the like) from the console 106 is input to the input terminal 301 as an information unit divided into data having a predetermined length. This information unit is shown in FIG. The information unit is a signal composed of a total of 107 bits obtained by adding user information W (8 bits) and null N (3 bits, all “0” bits) to a transmission signal (for example, composed of 96 bits) 501. . The transmission information transmitted as this information unit is represented by P (X). This information unit 502 is supplied to a CRC (Cyclic Redundancy Check) encoding unit 302. Here, the CRC code is referred to as an error detection code.

  The CRC encoding unit 302 generates a signal 503 obtained by CRC encoding the information unit 502 as shown in FIG. That is, for error detection, a 16-bit CRC code generated from the bit string of the information unit 502 is added to the end of the information unit 502 and supplied to the fixed bit insertion unit 303.

Here, CRC coding is an error correction coding method generated based on a generator polynomial defined by ITU-T (International Telecommunication Union Telecommunication Standardization Sector). For example, the ITU-T 16-bit CRC generator polynomial G (X) (also referred to as error detection code) is:
G (X) = 1 + X ⁵ + X ¹² + X ¹⁶ (1)
It is represented by Specifically, the 16-bit CRC code is
G (X) = 1 + 2 ⁵ +2 ¹² +2 ¹⁶ = 10001000000000100001 (2)
It becomes.

  Therefore, the CRC-encoded signal 503 in FIG. 5B, that is, the transmitted data F (X) is expressed by the equation (3).

F (X) = P (X) + G (X) (3)
In the fixed bit insertion unit 303, a signal 504 (128 bits) in which a 5-bit fixed bit “0” is added to the end of the CRC encoded signal as shown in FIG. Is generated.

  The convolutional coding unit 304 performs a convolutional coding process on the 128-bit signal 504 to which the fixed bits are added as shown in FIG. 5D to generate a 256-bit convolutional code 505.

  Here, the convolutional encoding process in the convolutional encoding unit 304 will be described. In this embodiment, the 128-bit signal 504 is subjected to convolutional coding (constraint length K = 6) at a coding rate R = 1/2, and the generator polynomial in this case is as follows.

G ₁ (D) = 1 + D + D ³ + D ⁵ (4)
G ₂ (D) = 1 + D ² + D ³ + D ⁵ (5)
Therefore, the convolutional coding unit 304 reads G1 (D) in the above expression (4) and G2 (D) in the above expression (5) alternately in the order of the expressions (4) and (5). A 256-bit convolutional code 505 is generated from the 128-bit signal 504.

  Now, in the wireless communication system, since the mobile station 704 is constantly moving, a burst error in which bit errors occur continuously due to fading or the like occurs. Since the error correction capability due to the burst error may not be sufficiently exhibited, the 256-bit convolutional code 505 is interleaved by the interleaving unit 305 and supplied from the output terminal 306 to the transmitting radio 107. In the interleaving method, for example, as shown in FIG. 11, a bit string of a 256-bit convolutional code 505 is first divided into 16 blocks of 16 bits each as shown in FIG. Next, the data is written in a two-dimensional memory (not shown) in the direction of the matrix of 16 rows and 16 columns in order from the first block. Then, 1, 17,... 248, 9,..., 256 bits are read from this memory in order from the first column in the column direction, and as shown in FIG. The data is divided and interleaved, and output from the output terminal 306 to the transmitting radio 107.

  The transmission radio 107 converts the interleaved signal into a predetermined radio format suitable for radio transmission. That is, it is converted into a radio frame 506 as shown in FIG. This radio frame 506 has the same configuration as the communication channel SC shown in FIG. 10 described above. In other words, the 256-bit convolutional code 505 is divided into two by interleaving and distributed and converted into a 96-bit TCH functional channel and a 160-bit TCH functional channel, respectively. The radio frame 506 is transmitted from the transmission radio 107 of the base station 702 to the mobile station 704 using the radio carrier F, for example.

  On the other hand, in the mobile station 704, this is received by the antenna 201 and supplied to the received signal processing unit 204 via the changeover switch 202 and the receiving unit 203. FIG. 4 is a block diagram illustrating a schematic configuration of the reception signal processing unit 204. In FIG. 4, at the input terminal 401, the baseband signal is converted by the receiving unit 203, and a predetermined transmission signal is separated from the radio frame 506 (shown in FIG. 5E). This transmission signal is reinterleaved by the reinterleaving unit 402, and 256-bit received data 507 including an error is generated as shown in FIG. 5F and supplied to the Viterbi decoding unit 403. Here, the 256-bit received data 507 including an error is transmitted from the transmission radio 107 of the base station 702 to the antenna 201 of the mobile station 704 via a radio channel. Since an error occurs in the received signal due to the influence of multipath or the aging of devices constituting the system, the received data 507 naturally includes an error.

The Viterbi decoding unit 403 obtains a Viterbi-decoded signal 508 as shown in FIG. That is, the Viterbi decoding unit 403 performs error correction, but after Viterbi decoding, an error check is performed using the CRC part 16 bits. In the Viterbi decoding unit 403, for example, a bit error with a BER of about 3 × 10 ⁻² is repaired and restored to the original signal without error. The Viterbi-decoded signal is output from the output terminal 406 as a reproduction signal output, and after a predetermined process, is output as sound from the speaker 205. In the case of data, it is displayed on the display unit 208.

  Further, the restored signal (original signal without error) from the Viterbi decoding unit 403 is converted into a 256-bit signal 509 by the convolutional encoding unit 404 as shown in FIG. Supplied to the unit 405. On the other hand, the received data 507 from the reinterleaver 402 is also supplied to the comparator 405. The comparison unit 405 compares the received data 507 with the convolutionally encoded data 509 and outputs the number of errors from the output terminal 407 as a BER. Therefore, if this BER is displayed on the display unit 208, the BER of the transmission line can be measured easily and accurately. Note that an error check is performed using the CRC portion of 16 bits. However, if an error is detected, the BER cannot be calculated. For example, “error is present”, “uncalculated” is displayed.

  As described above, in one embodiment of the present invention, the error rate BER can be detected using a transmission signal (such as voice or data) to be transmitted, so that the system is not stopped and a special mode is set. There is no need, and a highly reliable wireless communication system can be realized.

  In the embodiment described above, the method for calculating the error rate BER of the wireless communication system has been described. However, it is also possible to determine whether the received data is correct. Another embodiment of this will be described with reference to FIG. FIG. 12 shows a block diagram of a schematic configuration of another embodiment of the present invention. In FIG. 12, reference numeral 1201 denotes a calculation unit, 1202 denotes a changeover switch, and 1203 denotes a determination signal output terminal. In addition, the same code | symbol is attached | subjected to the same thing as FIG.

  12 is different from FIG. 4 in that the output signal of the Viterbi decoding unit 403 is input to the arithmetic unit 1201, the changeover switch 1202 is controlled by the output, and the determination signal output is output from the output terminal 1203. is there. This operation will be described below. First, consider a signal input from the Viterbi decoding unit 403 to the calculation unit 1201. The signal output from the Viterbi decoding unit 403 is a CRC-coded signal 503 shown in FIG. 5B, that is, the transmission data F (X) shown in the equation (3) is sequentially fixed bits. Insertion and addition (shown in FIG. 5C), convolutional coding (shown in FIG. 5D), radio frame (shown in FIG. 5E), received data (shown in FIG. 5F) And Viterbi composite (shown in FIG. 5G) and processed signal.

  Accordingly, the transmission information transition polynomial P ′ (X) obtained by performing the signal processing of the transmission information P (X) in FIGS. 5C to 5G is represented by the following equation.

Transition polynomial P ′ (X) = {the highest order term of G (X)} × P (X) (6)
If the remainder of P ′ (X) / G (X) is represented by a surplus polynomial R (X), and the received data is F ′ (X), F ′ (X) is given by expressed.

F ′ (X) = P ′ (X) + R (X) (7)
Therefore, the signal obtained from the Viterbi decoding unit 403 is supplied to the calculation unit 1201, and the calculation unit 1201 performs the following calculation to obtain a surplus surplus polynomial R (X).

P '(X) / G (X) (8)
When the above operation is performed, when the Viterbi decoding unit 403 performs Viterbi composite and the error is completely corrected, the transition polynomial P ′ (X) becomes the same as the transmission information P (X), and P '(X) / G (X) is divisible and no remainder is generated. That is, the surplus polynomial R (X) is 0. However, if error correction is not performed completely, P ′ (X) / G (X) is not divisible and a remainder is generated. That is, the surplus polynomial R (X) remains. In this case, there is a possibility that the transmission data is reproduced by mistake. In the embodiment of the present invention shown in FIG. 12, when the calculation result of P ′ (X) / G (X) is divisible by the calculation unit 1201, the changeover switch 1202 is turned on (closed), and the reproduction signal output is sent from the terminal 406. Output. On the other hand, if the calculation result of P ′ (X) / G (X) cannot be divided, the surplus polynomial R (X) remains, so it is determined that error correction is incomplete, and the changeover switch 1202 is turned OFF (opened). As a result, the reproduction output is not output from the terminal 406. Note that the calculation result of the calculation unit 1201 can be output from the terminal 1203 as a determination signal output and displayed on the display unit 208. That is, when the calculation result of P ′ (X) / G (X) is divisible by the calculation unit 1201, “No error” or “During signal reproduction” is displayed, and P ′ (X) / G (X) If the result of the calculation is not divisible, a warning message such as “There is an error” or “Signal playback stop” is displayed.

Furthermore, in the embodiment shown in FIG. 4, the bit error rate BER output from the comparison unit 405 after error correction is performed by the Viterbi decoding unit 403, for example, 3 × 10 ^{−2 in} this embodiment. If it is within the range, a signal is received, and if it exceeds this limit, the user is required to judge that the signal is not received. However, in the embodiment shown in FIG. 12, the signal reproduction output is based on the calculation result of the calculation unit 1201. Therefore, a highly reliable wireless communication system can be constructed. Even in this case, it is possible to output the bit error rate BER from the output terminal 407 of the comparator 405 and display the BER on the display unit 208, but this is the same as in the embodiment shown in FIG. It is.

  As described above in detail, according to the present invention, since a BER can be measured or an error determination can be performed using a transmission signal such as voice or data during operation of the wireless communication system, a special external device connection or maintenance mode can be connected to the base station. A wireless communication system capable of bit error measurement and error determination without setting a special mode such as the above can be realized.

  Although the present invention has been described in detail above, the present invention is not limited to the embodiments of the wireless communication system and the error measurement and error determination method of the wireless communication system described herein, and other wireless communication than the above-described ones. Needless to say, the present invention can be widely applied to error measurement and error determination method methods for systems and wireless communication systems.

The block diagram of schematic structure of the base station used by this invention is shown. 1 is a block diagram of a schematic configuration of a mobile station used in the present invention. The block diagram of schematic structure of the signal processing part of the base station used by this invention is shown. The block diagram of schematic structure of the received signal processing part of the mobile station used by this invention is shown. It is a figure for demonstrating the principle of this invention. 4 is a flowchart for explaining the operation of the mobile station of the present invention. It is a figure for demonstrating schematic structure of a SCPC system digital radio | wireless communications system. It is a figure for demonstrating the radio carrier used with the conventional SCPC system digital radio | wireless communications system. It is a figure for demonstrating the transmission frame structure used with the conventional SCPC system digital radio | wireless communications system. It is a figure for demonstrating the signal format used with the conventional SCPC system digital radio | wireless communications system. It is a figure for demonstrating the interleaving used by this invention. The block diagram of schematic structure of other one Example of this invention is shown.

Explanation of symbols

  101: signal processing device, 102: wireless device, 103: connection terminal, 104: signal processing unit, 105, 207: storage unit, 106: console, 107: transmission wireless device, 108: reception wireless device, 201: Antenna 202: changeover switch 203: reception unit 204: received signal processing unit 205: speaker 206: control unit 208: display unit 209: operation unit 210: microphone 211: transmission signal processing unit 212 : Transmission unit, 301, 401: Signal input terminal, 302: CRC encoding unit, 303: Fixed bit insertion unit, 304: Convolutional encoding unit, 305: Interleaving unit, 306, 406: Signal output terminal, 402: RE Interleaving unit, 403: Viterbi decoding unit, 404: Convolutional coding unit, 405: Comparison unit, 407: BER output terminal, 701: Controller, 702: Base , 703: communication area, 704: mobile station 705: transmission line, 1201: arithmetic unit, 1202: selector switch, 1203: determination signal output terminal.

Claims (3)

  A first base station; and a plurality of mobile stations that receive signals transmitted from the first base station through a radio channel. The first base station includes a signal processing unit, and the signal processing The mobile station transmits a transmission signal to which the error detection code is added to the mobile station, and the mobile station has a reception signal processing unit for processing the transmission signal to which the error detection code is added, and the reception signal processing unit Comprises means for correcting the error of the transmission signal, means for reproducing the output of the means for correcting error, and comparing means for comparing the output of the transmission signal and the means for correcting error. A wireless communication system characterized by outputting a bit error rate.   A first base station; and a plurality of mobile stations that receive signals transmitted from the first base station through a radio channel. The first base station includes a signal processing unit, and the signal processing The mobile station transmits a transmission signal to which the error detection code is added to the mobile station, and the mobile station has a reception signal processing unit that processes the transmission signal to which the error detection code is added. The received signal processing unit of the station performs error correction of the transmission signal to which the error detection code is added, compares the error-corrected signal with the signal before error correction, and outputs a bit error rate. A bit error rate measurement method for a wireless communication system.   A first base station; and a plurality of mobile stations that receive signals transmitted from the first base station through a radio channel. The first base station includes a signal processing unit, and the signal processing The mobile station transmits a transmission signal to which the error detection code is added to the mobile station, and the mobile station has a reception signal processing unit that processes the transmission signal to which the error detection code is added. The received signal processing unit of the station performs error correction of the transmission signal to which the error detection code is added, and divides the reception information P ′ (X) of the received data subjected to error correction by the error detection code G (X). An error determination method for a wireless communication system, wherein an error determination is made based on the presence or absence of a remainder.

Images