Hybrid automatic request retransmission system and method in free space optical communication

Abstract

The invention discloses a system and a method for hybrid automatic request retransmission in free space optical communication, and mainly solves the problem of reliability in an existing free space optical communication. In the system and the method for the hybrid automatic request retransmission in the free space optical communication, a blocking, error detecting and coding module achieves self-adaption blocking and error detection coding for sent data under the control of a self-adaption control module. An error correction coding module achieves error correction coding for error detection coded data. A diversity sending and controlling module achieves diversity sending for error correction coded data under the control of the self-adaption control module. A diversity receiving module achieves diversity receiving for received data. A code merging and error correction coding module achieves self-adaption code merging and error correction coding for diversity received data under the control of the self-adaption control module. The blocking, error detecting and coding module achieves block coding for the error correction coded data and requires retransmission. The system and the method for the hybrid automatic request retransmission in the free space optical communication improve reliability of a communication system, give consideration to communication instantaneity and transmission efficiency, and can be used in the field of the free space optical communication.

Description

technical field [0001] The present invention belongs to the technical field of communication, and further relates to a hybrid automatic repeat request (HARQ) system and method in free space optical communication (FreeSpace Optical, FSO) in the technical field of error control of free space optical communication. The invention can be used in a free space optical communication system that has higher requirements on real-time performance, reliability and transmission efficiency. Background technique [0002] Free space optical communication is a new type of broadband wireless communication technology that uses light (mainly laser) as a carrier to communicate in free space. It has many advantages such as high modulation rate, wide frequency bandwidth, large capacity, no spectrum resource occupation, good confidentiality, low cost, fast installation, transparent protocol, flexible and convenient networking, etc. It is recognized as one of the best ways for future broadband mobile...

AI Technical Summary

Problems solved by technology

However, the disadvantage of this method is that due to the duplication and CRC check of each block of the data frame, the amount of data is large and excessive redundant information is generated; the copied identical blocks are combined and sent together, It will increase the correlation between blocks, so that the received data cannot be fully combined, which is not conducive to improving the performance of code combination; and after decoding, the correct block is received, the wrong block is discarded, and no retransmission is performed, which will destroy the integrity of the transmitted data frame. integrity

The disadvantage of this method is that when applied to CDMA system, the number N of parallel transmission is equal to the number of orthogonal channel codes allocated by CDMA packet data communication system, which is a fixed value and cannot be adjusted adaptively with channel conditions, which is not conducive to Improvement of transmission efficiency; discard packets that still have errors after error correction and decoding and request retransmission, and retransmit the parallel redundant sending and parallel redundant combined reception of the entire packet data, so that even if the error is only concentrated in the packet For a small segment, the entire data still needs to be retransmitted, resulting in a reduction in transmission efficiency

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