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Encoding constraint and probability calculation based encoding and decoding synchronization method

A technology of probability calculation and coding constraints, applied in synchronization devices, digital transmission systems, electrical components, etc., can solve the problems of low performance and high complexity of synchronization algorithms

Inactive Publication Date: 2013-01-16
BEIJING INSTITUTE OF TECHNOLOGYGY
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Problems solved by technology

[0006] The purpose of the present invention is to improve the defects of high complexity and low performance of existing communication system synchronization algorithms, and propose a coding and decoding synchronization method based on coding constraints and probability calculations, combined with coding verification equations and probability calculation methods, to reduce system synchronization. Realize the complexity, improve the anti-jamming and noise performance of the wireless communication system

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  • Encoding constraint and probability calculation based encoding and decoding synchronization method
  • Encoding constraint and probability calculation based encoding and decoding synchronization method
  • Encoding constraint and probability calculation based encoding and decoding synchronization method

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Embodiment 1

[0055] Taking the (7, 4) Hamming code with n=7, k=4 as an example, "a codec synchronization method" described in the present invention is used to realize synchronization. The check matrix of the Hamming code is:

[0056] H = 0 1 1 1 1 0 0 1 0 1 1 0 1 0 1 1 0 1 ...

Embodiment 2

[0071] N=504 designed by R.Gallager, information length K=252, code rate 0.5, low-density parity-check code calculation synchronization. The encoding is regular LDPC encoding, the average row encoding degree is 6, the average column encoding degree is 3, and the actual transmission synchronization is at I=0 position. Calculate the value of the cost function C(I) for 1, 5 or 10 code groups respectively, and the synchronization results are as follows image 3 shown, where E b / N 0 = 1dB. The horizontal axis represents the offset I, and the vertical axis represents the value of the cost function C(I). Take L=1, 5 and 10 respectively to calculate the value of the cost function C(I). Through observation, it is found that under the conditions of three different L values, the peak probability of C(I) at I=0 is relatively large, and as the number of groups increases, the synchronization performance is significantly improved. Furthermore, when the number of received data groups pa...

Embodiment 3

[0073] In order to reduce the complexity of the receiver synchronization algorithm when the number of check equations of the error correction code used is large, in the calculation formula (4) of the cost function, select M'<M instead of M. That is, in the synchronization calculation of the LDPC in the above-mentioned embodiment 2, the synchronization probability calculation can be performed by adopting a partial check equation method, and a good synchronization effect can also be obtained.

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Abstract

The invention relates to an encoding constraint and probability calculation based encoding and decoding synchronization method, which belongs to the technical field of communication signal processing. The method comprises the following steps of: carrying out modulation on code elements subjected to error correction of encoding, and transmitting the code elements to a receiver; calculating a likelihood probability for each datum by using a receiving end, continuously selecting L*N+N received data starting from the first received datum, and grouping the received data according to a rule; calculating the posterior probability value of each data group so as to obtain posterior probabilities meeting each checkout equation and posterior probabilities which do not meet the checkout equations; and under the condition that the offset is 1, calculating the cost function C (I) of grouped data, and carrying out peak judgment on the cost function so as to obtain a synchronous position. According to the method, the synchronous position is obtained according to the encoding constraint of a transmitting sequence, and an operation of sending pilot signals is not required, therefore, the bandwidth resources are saved, the concealing of signals is facilitated, and the anti-intercept / capture performance for signals is improved; and the method has an operational capability at an extremely low signal-to-noise ratio (SNR), and can be operated at an SNR near a shannon limiting SNR.

Description

technical field [0001] The invention relates to an encoding and decoding synchronization method based on encoding constraints and probability calculation, and belongs to the technical field of communication signal processing. Background technique [0002] Synchronization has always been one of the bottleneck technologies of communication systems. It is very important for wireless communication systems, especially for modern military and civilian communication systems based on OFDM modulation. Among them, frame synchronization or block synchronization technology is essential for wireless communication system design, and is also closely related to system performance. With the rapid development of communication technology, the deep concealment of signal transmission and reception is becoming more and more important than reducing system complexity and improving system effectiveness. [0003] The ideal maximum likelihood synchronization algorithm is relatively simple to design a...

Claims

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Application Information

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IPC IPC(8): H04L1/00H04L7/00
Inventor 李祥明卢继华卜祥元安建平李林涛
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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