JPH07336367A - Radio communication equipment - Google Patents

Abstract

PURPOSE:To obtain a radio communication equipment which is capable of holding high transmission efficiency, maintaining high error correction capacity, by providing a function performing an error correction encoding for received data for every fixed length. CONSTITUTION:A radio adapter part 2, transfers the data packet received from a terminal 1 to a RAM 5 via a LAN controller 3. A CPU 4 transmits the data stored in the RAM 5 to an error correction coder/decoder 6 and performs an error correction encoding for every fixed length. By this constitution, the keeping of high transmission efficiency becomes possible, maintaining high error correction capacity. It is desirable that a packet to be transmitted to a line be composed of plural cord words. When the received data packet is not the multiple of a fixed length for performing an error correction encoding, it is desirable that a means adding arbitrary data and the information showing the length except the length of arbitrary data added from a packet length to the packet to be transmitted be included.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication device for transmitting data in packet units.

[0002]

2. Description of the Related Art As digital wireless communication spreads, the number of cases in which data communication is performed by wireless lines has increased.
In addition, an error correction code has been used to secure the bit error rate required for data communication on a wireless line.

In the past, when an error correction code was used to transmit data in packet units, one codeword was transmitted as one packet.

[0004]

However, one codeword is converted into one
There were the following problems when sending as one packet.

(1) The longer the packet length is, the more the overhead such as the header is reduced and the transmission efficiency is high. However, when the long packet length is used to increase the transmission efficiency, the codeword length is also increased. However, when compared with the same hardware scale, if the codeword length is long, the correction capability becomes poor.

(2) However, if a short codeword length is used to improve the correction capability, the packet length becomes short and the transmission efficiency drops.

An object of the present invention is to provide a wireless communication device capable of maintaining high transmission efficiency while maintaining high error correction capability.

[0008]

According to the present invention, there is provided a digital radio communication apparatus, a means for receiving a data packet, a means for performing error correction coding on the received data for each fixed length, and a plurality of code words. And means for sending the data to the line.

[0009]

FIG. 1 is a block diagram showing the internal structure of a wireless adapter section which constitutes a digital wireless communication apparatus according to an embodiment of the present invention.

The wireless adapter unit 2 is connected to the data terminal 1 via a LAN controller 3 such as Ethernet, and controls the wireless adapter unit 2 with a CPU 4, a RAM 5 for storing various data, and an error correction encoder. Decoder 6 and communication controller 7 that assembles and disassembles packets
A bit synchronization circuit (DPLL) 8, a radio unit 9 including a modulation / demodulation unit, an antenna 10, and a data bus 11.
Have and.

The CPU 4 sends a channel selection signal 13 to the radio unit 9 and receives a carrier detection signal 12 from the radio unit 9.

Further, FIG. 2 is an explanatory diagram showing an encoding system in this embodiment, and FIG. 3 is an explanatory diagram showing an outline of a frame structure used in this embodiment. In addition, FIG.
3 is a block diagram showing the flow of data in the wireless adapter unit 2. FIG.

As shown in the figure, in this embodiment, two types of error correction coding (C1, C2) are performed on the data received from the LAN controller 3.

FIG. 5 is a sequence chart showing the operation in the first embodiment of the present invention, and FIGS. 6 and 7 are flow charts showing the operation on the transmitting side and the receiving side in the first embodiment.

In this embodiment, the case where data is transmitted from the data terminal A (wireless adapter A) to the data terminal B (wireless adapter B) will be described below.

First, in the data terminal A, when a data transmission request is generated, the frequency channel 1 is transmitted in S1.
The data terminal A transmits data to the wireless adapter A waiting in (F1) (S2). The data is transferred to the RAM 5 via the LAN controller 3.

At this stage, it is necessary to determine the wireless channel for transmitting data between the wireless adapter A and the wireless adapter B. Since the wireless adapter B is on standby in the predetermined frequency channel 1 (F1) (S2
1), the wireless adapter A needs to monitor the use status of the frequency channel 1 using the carrier detection signal (S3), and if the channel is idle, it is necessary to send the control packet shown in FIG.

This control packet includes a destination address, a frequency channel number used for data transmission (for example, No. 4), a packet type (transmission request or reception permission).
24 bytes of data are included, and RAM5
It is stored in. When this control packet is sent, the data obtained by adding the wireless header to the control data written in the RAM 5 is sent as it is to the wireless line as a packet. That is, since the control packet is as short as 30 bytes or less, the probability of causing an error during transmission is low, and the error correction coding process is not performed. After this transmission, CP
U4 switches channels by channel select signal,
Standby in frequency channel 2 (S5).

On the other hand, the wireless adapter B on the receiving side also connects the selector to the RAM 5 and stands by on the channel 1. If the CRC check result of the control packet sent here reveals that there is an error in the packet, a resend request is issued. If no error is detected, a control packet that acknowledges the start of transmission is transmitted via frequency channel 2 (F2) and switched to frequency channel 4 and stands by (S2).
2 to S25).

When the wireless adapter A receives the control packet of the wireless adapter B (S6), the terminals of each other can determine the frequency channel for transmitting the data packet, so that the wireless adapter starts transmitting the data packet. To do. This data packet is longer than the control packet and has a length of about 100 to 1500 bytes.

Therefore, the use status of the frequency channel 4 to be used is monitored in the same procedure as when transmitting the control packet,
If the channel is used, it waits until the channel becomes free, and when the channel becomes free, the data packet transmission procedure is entered. However, when transmitting this data packet, the data packet is first received from the terminal and stored in the RAM 5. The stored data is sent to the error correction encoder 6 to perform error correction coding.

In this embodiment, as the error correction code, a Reed-Solomon code configured as a product code as shown in FIG. 2 is used, and a (196, 144) code having a code length of 196 bytes is used.

Upon receiving the data from the terminal A, the wireless adapter A counts the length of the received data and determines whether it is a multiple of 144 bytes (S8).

If the received data is a multiple of 144 bytes, the data is sent to the error correction encoder 6 as it is (S10).

If the received data is 144 bytes or less, for example, 100 bytes, 44 bytes, which is a difference from 144 bytes, is added to the "FF" data and sent to the error correction encoder 6. If the length of the received data is 144 bytes or more, "FF" data is added to the error correction encoder 6 in the same manner so as to be a multiple of 144 and sent to the error correction encoder 6 (S
9). For example, when the received data length is 1000 bytes, the minimum multiple of 144 of 100 or more is 1008, so that data of 8 bytes is added.

The error correction encoder 6 outputs the encoded data 196 bytes at a time and stores it in the RAM 5. Next, data is sent from the RAM 6 to the communication controller 7, and in the communication controller 7, a flag, data indicating the data length (for example, 1000) received from the terminal, a destination, a source address, a CRC check unit for error detection, etc. After the wireless header of No. 1 is added, it is sent to the wireless line (S11).

In the receiving side wireless adapter B, when the addresses match, the received data is stored in the RAM 5 (S26). Then, the data is input from the RAM 5 to the error correction decoder 6 in units of 196 bytes, and the received data is corrected (S29).

When no uncorrectable error is detected in the received packet (S30), a reception response packet is assembled and the packet is sent to the wireless adapter A using channel 4 (S31). . Since the reception response packet is short, it is sent to the wireless line without error correction coding.

The data in units of 144 bytes output from the error correction decoder 6 is again stored in the RAM 5 and then sent to the terminal 1 via the LAN controller 3 (S32). That is, the "FF" data added at the time of transmission is deleted here.

If an uncorrectable error is detected in the received packet (S30), a resend request is sent (S33), and the packet waits for S26.

When the receiving side receives the reception response packet,
If the data transmission operation is completed and the power is not turned off (S
13), while waiting for the next data reception from the terminal,
It waits on channel 1 in preparation for receiving a control packet from another wireless adapter.

If there is a resend request (S12),
Returning to S11, the packet is retransmitted.

As described above, by providing the means for receiving the data packet, the means for performing the error correction coding on the received data for each fixed length, and the means for sending the coded data to the line, any data can be provided. It is possible to maintain high correction efficiency for long data and at the same time maintain high transmission efficiency.

In the first embodiment described above, the Reed-Solomon code of (196, 144) is used as the predetermined code, but other different codes such as BCH code can be used. Is.

It is also possible to change the coding rate (transmission data amount / parity data amount) or the like according to the line status. That is, it is possible to lower the coding rate to improve the correction capability when the line condition is poor, and to increase the transmission efficiency by increasing the coding rate when the line condition is good. It should be noted that the data length to be added will change with the change in the coding rate even if the data length received from the terminal is the same.

Further, in the first and second embodiments,
The spread spectrum communication system, especially the low frequency frequency hopping system was used. However, the present invention is not limited to these communication systems, and the same effect can be obtained with any communication system as long as there is a communication line connecting two points. For example, in a system such as a frequency division multiplexing system (FDMA) or a time division multiplexing system (TDMA), the same frame format and the same data addition method as those shown in the embodiments are used to obtain the same effect. It is possible to obtain.

Further, in each of the above embodiments, the configuration in which the wireless adapter receives data from the terminal has been described. However, the part that performs error correction processing does not necessarily have to be physically separated from the data generation source.
For example, even when the data terminal itself has an error correction processing function and a wireless transmission function, the same effect can be obtained with the same configuration. In this case, for example, the output of the calculation result serves as a data generation source, and after the output data error correction processing is performed, the data is transmitted to the wireless line.

[0038]

As described above, according to the present invention,
In a digital wireless communication device, by providing a means for receiving a data packet, a means for error-correcting encoding the received data for each fixed length, and a means for transmitting the encoded data to a line, high error correction is achieved. There is an effect that it is possible to maintain high transmission efficiency while maintaining the capacity.

[Brief description of drawings]

FIG. 1 is a block diagram showing an internal configuration of a wireless adapter unit that constitutes a digital wireless system according to an exemplary embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an encoding method in the above embodiment.

FIG. 3 is an explanatory diagram showing an outline of a frame configuration used in the above embodiment.

FIG. 4 is a block diagram showing the flow of data in the wireless adapter unit in the above embodiment.

FIG. 5 is a sequence chart showing an operation in the above embodiment.

FIG. 6 is a flowchart showing the operation of the transmitting side of the above embodiment.

FIG. 7 is a flowchart showing the operation of the receiving side of the above embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Data terminal, 2 ... Wireless adapter part, 3 ... LAN controller, 4 ... CPU, 5 ... RAM, 6 ... Error correction encoder / decoder, 7 ... Communication controller, 8 ... Bit synchronization circuit, 9 ... Wireless part, 10 ... Antenna, 11 ... Data bus.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location H04Q 7/38 H04L 1/00 B H04B 7/26 109 M

Claims (4)

[Claims] 1. Receiving means for receiving data packets,
A wireless communication device comprising: an error correction coding means for performing error correction coding on the received data for each fixed length; and a sending means for sending the coded data to a line. 2. The wireless communication device according to claim 1, wherein the packet transmitted to the line is composed of a plurality of code words. 3. The method according to claim 1, wherein when the received data packet is not a multiple of a fixed length for error correction coding, an addition unit for adding arbitrary data and a packet length for the packet to be transmitted are added. A wireless communication device including information indicating a length excluding the length of the generated arbitrary data. 4. A receiving means for receiving data from a line, a decoding means for decoding the received data, a reading means for reading information indicating a data packet length, and a reading means according to the read information according to claim 1. A wireless communication device comprising: a deleting unit that deletes arbitrary data added at the time of transmission.