JPH07143101A - Diversity system - Google Patents

Abstract

PURPOSE:To prevent the missing of data at line switching caused in a conventional diversity system. CONSTITUTION:After transmission data 1 are coded by an error correction coder 2, each bit information of a code is sent simultaneously through plural channels by using transmitters 3 whose frequencies differ from each other and a transmission antenna 5. Plural receivers 8 of a receiver side receive each bit information of the code through a reception antenna 6 simultaneously and an error correction decoder 9 corrects an error.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity system for preventing data loss caused by fading (radio wave interference) in digital communication.

[0002]

2. Description of the Related Art As a conventional diversity system, a space diversity system and a frequency diversity system are shown in FIG.
This will be described with reference to FIG. In the space diversity system, as shown in FIG. 4, from the transmitting side, transmission data 1 is encoded by an error correction encoder 2 and then serially transmitted by a transmitter 3 through a transmitting antenna 5. In contrast,
On the receiving side, after receiving the transmitted waves by the two receiving antennas 6 having different positions or polarization planes, the changeover switch 11 selects the antenna having the appropriate receiving state, and the receiver 8 and the error correction decoder 9 receive the received data 10. obtain. In the frequency diversity system, as shown in FIG. 5, from the transmitting side, the transmission data 1 is encoded by the error correction encoder 2 and then the same data is transmitted by the transmitter 3 using a plurality of different frequencies f ₁ and f _2.
To transmit serially through the transmitting antenna 6. On the receiving side, after receiving the transmitted wave with the receiving antenna 6,
Of the outputs of the plurality of receivers 8 corresponding to the frequency, the changeover switch 11 selects the one having the proper reception state, and the error correction decoder 9 obtains the reception data 10.

[0003]

As described above, in the conventional diversity system, transmission data is error-correction-encoded and then serially transmitted in order of one bit or several bits, and a plurality of different positions, polarization planes or frequencies are transmitted. This is a method of selecting an appropriate line from those received on the line. Therefore, the line is switched by the changeover switch 11 after detecting an error in data, so that correct data cannot be obtained and data is lost during the period from the beginning of the occurrence of data error to the end of the line switching. Therefore, an object of the present invention is to provide a diversity method capable of preventing data loss.

[0004]

In order to achieve the above object, the diversity system of the present invention performs error correction coding on transmission data, and then simultaneously transmits each bit information of one code by a plurality of lines having different frequencies. It is characterized by that.

[0005]

With the above structure, the transmission data is transmitted in parallel for each code length after error correction coding. Therefore, as long as a data error occurs in a line with less than the error correction capability among lines with different frequencies, the error is corrected by the error correction decoder on the receiving side. It is possible to prevent omission.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings along with embodiments. FIG. 1 shows an embodiment to which the diversity system of the present invention is applied, FIG. 2 shows a configuration example of an error correction encoder, and FIG. 3 shows a configuration example of an error correction decoder.

In FIG. 1, the transmitter comprises an error correction encoder 2, a plurality of n transmitters 3 having different transmission frequencies f _{1 to} f _n , a frequency synthesizer 4, and a transmission antenna 5. On the other hand, the receiving device includes a receiving antenna 6, a frequency distributor 7, a plurality of n receivers 8, and an error correction decoder 9.
Consists of.

On the transmitter side, the error correction encoder 2 encodes the transmission data 1 having a data bit length of m bits into data having a code length of n bits (n> m). In the example of FIG. 2, the error correction encoder 2 includes an m-bit shift register (SR) 12 and an n-bit shift register (SR) 1.
3, an appropriate coefficient unit 14, an exclusive OR unit 15, and a delay unit 16. In this error correction encoder 2,
The transmission data 1 is output as it is from the 1st bit to the mth bit, and the coefficient unit 14, the exclusive OR unit 15, and the delay unit 16 are used to output nm check bits by the algorithm of the cyclic code. It is generated and added to the transmission data 1 to output n-bit parallel data as a whole. This n-bit data is transmitted in parallel with a transmission frequency f
_The signals are converted into electromagnetic waves by a transmitter 3 different from _{1 to} f _n , then the respective electromagnetic waves are combined by a frequency synthesizer 4, and then transmitted by a transmission antenna 6. As a result, after the m-bit transmission data 1 is error-correction coded into n-bit data, each bit information of one code is simultaneously transmitted by n lines having different frequencies such as f _{1 to} f _n. It

On the receiving device side, the transmitted wave is received by the receiving antenna 6
Then, the frequency divider 7 divides each frequency of f _{1 to} f _n by the frequency divider 7, and the receiver 8 of each frequency divides the frequency by n.
The bit parallel data is reproduced, and the error correction decoder 9 obtains m-bit received data 10 from the n-bit parallel data. The error correction decoder 9 is n in the example of FIG.
A bit buffer register (R) 17, an m bit buffer register (R) 18, an error position memory 19,
It is composed of an appropriate coefficient unit 20 and exclusive OR units 21 and 22. In this error correction decoder 9, a coefficient unit 20 is used to convert n-bit parallel data by using a cyclic code algorithm.
And the error bit is detected by using the exclusive OR device 21 and the position thereof is stored in the error position memory 19, and this information is used to perform the exclusive OR on the parallel data of the 1st bit to the mth bit. The error correction is performed by the device 22, and the m-bit received data 10 is output. As a result, the frequency f
_{When a} data error occurs due to fading on a line having an error correction capability number or less out of n lines different from _{1 to} f _n , the error is corrected by the error correction decoder 9 on the reception side using n-bit parallel data. Corrected to prevent data loss.

[0010]

As described above, after the transmission data is error-correction-encoded, the conventional diversity system transmits the data serially, that is, one bit at a time or several bits at a time, whereas the diversity of the present invention. In the system, bit information of one code is transmitted at the same time, that is, in parallel for each code length, by a plurality of lines having different frequencies. By transmitting the data after error correction coding in parallel in this way, as long as a data error occurs in a line having an error correction capability number or less among a plurality of lines having different frequencies,
Since the error is corrected by the error correction decoder on the receiving side,
There is no need for line switching, and it is possible to prevent data loss that occurred during line switching in the conventional diversity method. Therefore, it is extremely useful as a digital communication technology.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a diversity system of the present invention.

FIG. 2 is a diagram showing a configuration example of an error correction encoder.

FIG. 3 is a diagram showing a configuration example of an error correction decoder.

FIG. 4 is a diagram showing a conventional space diversity system.

FIG. 5 is a diagram showing a conventional frequency diversity system.

[Explanation of symbols]

 1 transmission data 2 error correction encoder 3 transmitter 4 frequency synthesizer 5 transmission antenna 6 reception antenna 7 frequency distributor 8 receiver 9 error correction decoder 10 reception data

Claims (1)

[Claims] 1. After the transmission data is error correction coded,
A diversity system in which bit information of one code is simultaneously transmitted through a plurality of lines having different frequencies.