Research On Sequence Verification Based On Double Detection For PCSS

Parallel Combined Spread Spectrum(PCSS)communication technology is a highly efficient parallel multi-band spread spectrum technology which is derived from the soft spectrum spread spectrum technology.This technology has high information transmission capacity and band utilization rate,and also has the characteristics of ordinary spread spectrum communication system,such as strong ability of Anti-interference,better concealment and other advantages.So it has a good development and application prospects.PC/SS communication system takes a combination of r PN sequences out of M PN sequences through data-sequence mapping algorithm and then transmit.Due to the influence of noise and interference at the receiving end,the r decision PN sequences which selected by maximum value determinator may be wrong and are not always the transmitted PN sequences.Once the decision sequence is wrong,it will cause a lot of errors.But the existing PC/SS systems rarely have the ability to examine and correct the error decision sequence.In order to solve this problem,this paper studies the detection and correction of the received decision sequence to improve the anti-jamming performance of the system and reduce the system error rate.The main contents and achievements are as follows:(1)Based on the statistics of the misjudgment steps of the received decision sequence in different signal-to-noise ratios,different sequence lengths and different coding patterns,formula relation checking algorithm is proposed by analyzing the relationship between the numbers of candidate sequences and the PN sequences with strong binding were selected as the transmission sequence.Theoretical analysis and simulation results show that the formula relation checking algorithm can correct the error of all sequences by 1 step,if the polarity of the transmission sequence is fixed at the same time,it is also possible to correct the partial error condition where the error step is greater than 1 and reduce system bit error rate by 1 to 2 orders of magnitude compared to conventional systems under the same conditions.The anti-jamming performance of PC/SS system is greatly improved.(2)The correlation of different spreading sequences before and after cyclic shift was analyzed,and combining with the relationship between the number of sequence and shift,the PC/SS system with double information matching was proposed which solves the problem of the lack of information transmission ability of the formula relation checking algorithm.Theoretical analysis and simulation results show that the algorithm can be used as a new sequence decision method under the condition of large SNR,which has a good error performance in the PCSS system based on chaotic sequence.The number of information bits per cycle can be increased by 6 bits,4 bits and 3 bits compared with the formula relation checking algorithm like the formula relation of multiplication,addition and remainder.However,the complexity is increasing and the computation amount is large.(3)The PCSS system based on the double matching algorithm guarantees the data transmission efficiency,but it needs to work under the large SNR condition and is more suitable for the PCSS system with the chaotic sequence.By analyzing the partial rule of the error sequence in receiver and the error sequence and the correct sequence distribution in different sequence codes of the PCSS system,the system based on the successive contrast method is proposed to reduce the system error rate.Theoretical analysis and simulation results show that the successive contrast algorithm can effectively reduce the system error rate under different spreading sequences.