JP2005101727A - Municipality digital transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a municipality digital communication system realizing an optimal transmission type automatically depending on the communication connection state of a slave station regardless of the degree of knowledge of an operator. <P>SOLUTION: The municipality digital communication system comprising a control station 10, a base station 20 and a plurality of slave stations 31, 32 and 41 has an error rate table for storing the data transmission error rate each of the plurality of slave stations, and a transmission type table for storing the transmission type concerning an arbitrarily determined threshold of transmission error rate wherein transmission from the control station to an arbitrary slave station is determined with reference to the error rate table and the transmission type table. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a data transmission system in a municipal digital communication system comprising a control station, a base station, and a plurality of slave stations.

  In the conventional regional disaster prevention radio system, during the connection of the line between the control station and the mobile station such as the mobile station, the handler of the slave station uses a voice message from the voice message output unit provided in the slave station to The communication connection state can be known, and therefore the data transmission method can be selected according to the communication connection state of the slave station (see Patent Document 1).

  Also, in a disaster prevention administrative radio system that includes a control station and multiple slave stations, and the control station and each slave station are connected by both satellite and ground lines, the control station issues a simultaneous command to the slave stations. When the control station sends a simultaneous command start signal via both the above-mentioned lines, the slave station receives the simultaneous command with the previously received simultaneous command start signal so that the simultaneous command is more reliable. In addition, a technique for transmitting more quickly has been proposed (see Patent Document 2).

  Also, a radio interface (modulation method is quaternary digital) in a municipal digital communication system using a TDMA (Time Division Multiple Access) method among the narrow-band digital communication methods in the 260 MHz band defined in Article 57-3-2 of the Radio Equipment Regulations. (Corresponding to a 兀 / 4 shift QPSK system and a channel interval of 25 KHz) is defined (Non-Patent Document 1).

JP 2002-135849 A.

Japanese Patent Laid-Open No. 10-271063.

ARIB STB-T79, “Municipal Digital Communication System”, p1, p10-11. p108 etc.

  However, in the regional disaster prevention radio system of the above-mentioned patent document 1, if a handler of a slave station such as a mobile station does not recognize the characteristics of the data transmission scheme, an appropriate data transmission scheme according to the communication connection state of the slave station It was impossible to choose.

  Moreover, in the disaster prevention administrative radio system of the said patent document 2 already proposed, selecting an appropriate data transmission system according to the communication connection state of a slave station is not touched.

  In addition, in the wireless interface in the municipal digital communication system of Non-Patent Document 1 described above, there is no mention of an appropriate data transmission method according to the communication connection state of the slave station.

  An object of the present invention is to provide a municipal digital communication system that automatically realizes an appropriate transmission type according to the communication connection state of a slave station, regardless of the level of knowledge of the handler.

  In order to solve the above problems, the present invention provides an error rate table for storing a data transmission error rate for each of the plurality of slave stations in a municipal digital communication system comprising a control station, a base station, and a plurality of slave stations. And a transmission type table for storing a transmission type relating to an arbitrarily determined threshold value of the transmission error rate, between the control station and any slave station with reference to the error rate table and the transmission type table. It is characterized in that a decision to make a transmission is made.

  Further, in the present invention, the base station allocates data using a plurality of transmission slots when the data amount of the data transmission is larger than an arbitrary data amount according to the data transmission decision by the control station, and the plurality of slots Is transmitted to the same slave station.

  According to the present invention, there is an effect of obtaining a municipal digital communication system that automatically realizes an appropriate data transmission method according to a communication connection state of a wireless device, regardless of the level of knowledge of the operator.

  Embodiments according to the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a diagram showing a configuration of a municipal digital communication system in an embodiment according to the present invention. In FIG. 1, 10 is a control station, 20 is a base station, 31 and 32 are mobile stations that wirelessly communicate with the base station 20, 41 is a relay terminal station that wirelessly communicates with the base station 20, and 33 is wirelessly communicated with the relay terminal station 41. Indicates the mobile station to be operated. In addition, the municipal digital communication system also includes a plurality of mobile stations that communicate with each other and a plurality of mobile stations that communicate wirelessly with a relay station.

  Thus, the base station 20 communicates wirelessly with the mobile stations 31 and 32, which are a plurality of slave stations, and the relay terminal station 41. The relay terminal station 41 communicates with the mobile station 33 by radio.

  FIG. 2 is a diagram illustrating an example of mapping of communication channels to radio carriers in the base station 20 according to the embodiment of the present invention. In the base station 20, when the data amount of data communication is larger than an arbitrary data amount, data is allocated using a plurality of slots of radio carriers, and the plurality of slots are assigned to each of the mobile stations 31, 32 and the relay terminal station 41. Wireless communication.

  FIG. 3 is a diagram showing an example of the error rate table 51 and the transmission type table 52 that the control station 10 has in the embodiment according to the present invention. The error rate table 51 stores a data transmission error rate for each of a plurality of slave stations. In addition, the transmission type table 52 stores a transmission method indicating a transmission type related to an arbitrarily determined threshold of the transmission error rate and data to be transmitted.

  The error rate table 51 stores a data transmission error rate related to each slave station No. of a plurality of slave stations as an error (BER) rate statistical value. Each of the mobile stations 31, 32 and the relay terminal station 41, which are a plurality of slave stations, calculates a transmission error rate of received data for each reception, and at each reception, or arbitrarily for each period, or from the master station Each time an inquiry transmission is received, a reply is made by either or a combination thereof.

  With this reply, the control station 10 updates and stores an error (BER) rate statistical value related to each of the plurality of slave stations. In accordance with the updated and stored error (BER) rate statistical value, based on the predetermined transmission type table 52, an appropriate transmission method corresponding to the updated and stored error (BER) rate statistical value is selected and data is transmitted. .

  In the example of the transmission type table 52, the transmission method is different depending on whether the error (BER) rate statistical value is 80 or more, 65 or more, less than 80, or less than 65.

  If the error (BER) statistic value is 80 or higher, FEC (Forward Error Correction): Sends data with error correction code added in advance on the transmission side. If there is an error in the received data, an error occurs on the reception side. (Some corrections are made), with 1 transmission slot for audio, 2 slots for text 1 less than XX bytes, 2 slots for text 2 XX bytes or more, 3 slots for JPEG, 3 slots for MPEG Using the assignment, the base station 20 is instructed to assign data to the slot and perform wireless communication.

  The base station 20 transmits the designated data by the designated transmission method according to the command to the mobile stations 31 and 32 and the relay terminal station 41 which are a plurality of slave stations.

  If the error (BER) statistic value is the next highest 65 or less and less than 80, ARQ (Automatic Repeat Request: if an error is detected in the received data, the signal is discarded and the signal is received by requesting retransmission) With a transmission method, data is assigned to a slot by using slot assignments of less than XX bytes of text 1, 2 slots of XX bytes or more of text 2, 3 slots of JPEG, and 3 slots of MPEG. The base station 20 is instructed to perform wireless communication.

  The base station 20 transmits the designated data by the designated transmission method according to the command to the mobile stations 31 and 32 and the relay terminal station 41 which are a plurality of slave stations. In the transmission method with ARQ, since the line efficiency deteriorates when an error occurs, the voice that requires real-time property is not transmitted.

  If the error (BER) statistic is lower than 65, the normal transmission method without FEC or ARQ is 1 slot for voice, 1 slot for text 1 less than XX bytes, 2 slots for text 2 XX bytes or more. The base station 20 is instructed to wirelessly communicate data by allocating data using the slot allocation of 2 slots for JPEG and 3 slots for MPEG.

  The base station 20 transmits the designated data by the designated transmission method according to the command to the mobile stations 31 and 32 and the relay terminal station 41 which are a plurality of slave stations.

  The error (BER) rate statistics returned from each of the mobile stations 31 and 32 that are a plurality of slave stations and the relay terminal station 41 are the peripheral values of each of the mobile stations 31 and 32 that are the slave stations and the relay terminal station 41. It depends on the situation.

  In this case, for 80 slave stations with a high error (BER) rate statistic, in the transmission method with FEC, voice is 1 slot, text 1 less than XX bytes is 2 slots, text 2 is XX bytes Using the above slot allocation of 2 slots, JPEG 3 slots, and MPEG 3 slots, data is allocated to slots and wireless communication is performed.

  Also, when the error (BER) rate statistic value is low 63, the normal transmission method without FEC or ARQ, the voice is 1 slot, the text 1 less than XX bytes is 1 slot, and the text 2 XX bytes or more is 2 Using slot assignments of slots, 2 slots for JPEG, and 3 slots for MPEG, data is assigned to slots and wireless communication is performed.

  Also, for the 70 slave stations with the next highest error (BER) statistics, the transmission method with ARQ is 2 slots for text 1 less than XX bytes and 2 slots for text 2 more than XX bytes. , JPEG is assigned to 3 slots, and MPEG is assigned to 3 slots, and data is assigned to slots and wireless communication is performed.

  The error rate table of FIG. 3 described above is an error (BER) rate statistic value of each of the slave stations. When one group is assigned to a plurality of slave stations, any one of the error rate tables of FIG. Statistics of error rates (BER) of all the slave stations belonging to the group can be set for each group.

  In the case of group transmission in which transmission is performed for all slave stations belonging to an arbitrary group, an appropriate table is obtained by referring to a table that is a statistic of the error rate of the group and by referring to the transmission type table. Transmission can be performed. Details will be described below.

  FIG. 4 is an example of a chart showing the relationship between the error rate statistic value, group transmission availability / non-permission, and transmission method in the embodiment according to the present invention. When transmission is performed from an arbitrary slave station to all of the slave stations belonging to any other group, a regulation is provided in the transmission scheme, that is, in the case of the FEC scheme and the normal scheme.

  Therefore, when the statistical value of the error (BER) rate is as high as 80 or more, the FEC transmission method is selected and the transmission rate is low. In addition, when the statistical value of the error (BER) rate is as low as less than 80 or intermediate, a normal transmission method is selected, and the transmission rate becomes high.

  Then, the slot allocation is performed according to the slot allocation according to the transmission amount in the transmission type table of FIG. 3 described above. In the case of group transmission, since the ARQ scheme is inappropriate, it is not selected.

  FIG. 5 is a diagram showing an example of an operation flowchart for determining a transmission type in the embodiment of the present invention. In the case of transmission, when the transmission destination is individual (that is, not a group), the error rate table in FIG. 3 is referred to, the transmission type table is referred to, the FEC method, the ARQ method, or the normal The system is selected, slot allocation is performed according to the transmission amount, and transmission is performed.

  If the transmission destination is a group (that is, not individual), the FEC method or the normal method is selected as shown in FIG. 4 with reference to the error rate table in FIG. 3, and the selected transmission is selected. According to the method and transmission amount, slot assignment is performed according to the transmission type table of FIG. 3, and transmission is performed.

  Specifically, referring to the error rate table of the destination group and including a slave station with a high error rate, for example, the error rate is set to 80 or higher or 65 or higher, and the transmission method is set. If it is high, the FEC method is selected. If not, the normal transmission method is selected.

  As described above, in the present embodiment, various tables of the control station are referred to between the control station and an arbitrary slave station, and transmission is performed by selecting an appropriate transmission type via the relay station. Also, between any slave station and any other slave station, transmission is performed by referring to various tables of the control station and selecting an appropriate transmission type via the relay station. Further, the transmission is performed with the transmission method appropriately selected depending on whether the transmission destination is an individual or a group.

  In the embodiment described above, the error rate table and the transmission type table in FIG. 3 are provided in the control station, but by providing the same table in the memory of the slave station, The slot assignment at the base station can be selected at the time of the call.

  Therefore, according to the present embodiment, it is possible to automatically determine and implement a transmission method indicating an appropriate transmission type according to the communication connection state of the slave station at the control station or the slave station.

It is a figure which shows the structure of the municipal digital communication system in embodiment which concerns on this invention. It is a figure which shows the example of mapping to the radio carrier of the channel for communication in the base station of embodiment which concerns on this invention. It is a figure which shows the example of the error rate table and transmission classification table which a control station has in embodiment which concerns on this invention. It is an example of the figure which shows the relationship between the error rate statistical value, the possibility of group transmission, and a transmission system in embodiment which concerns on this invention. It is a figure which shows the example of the operation | movement flowchart which determines the transmission classification in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Control station, 20 ... Base station, 31, 32, 33 ... Mobile station, 41 ... Relay terminal station, 51 ... Error rate table, 52 ... Transmission type table.

Claims (2)

  In a municipal digital communication system comprising a control station, a base station, and a plurality of slave stations, an error rate table for storing a data transmission error rate for each of the plurality of slave stations is provided, and the transmission error rate is arbitrarily determined A transmission type table for storing a transmission type related to a threshold value, and a decision is made to perform transmission between the control station and an arbitrary slave station with reference to the error rate table and the transmission type table. Municipal digital communication system. 2. The municipal digital communication system according to claim 1, wherein the base station allocates data using a plurality of transmission slots when the data amount of the data transmission is larger than an arbitrary data amount according to the data transmission decision by the control station. A municipal digital communication system, wherein the plurality of slots are transmitted to the same slave station.

Images