The Design Of Zero Correlation Zone Complementary Sequence And The Research In The Physical Layer Network Coding

The rapid development of wireless communication technologies and rich mobile multimedia services, accelerating the application of wireless communications at all levels. Spread spectrum communication is widely used because of its good interference ability and confidentiality. And the various properties of the spread spectrum communication system is closely related to the basic parameters of the spreading sequence, so designing the spreading sequence with good correlation properties and large-capacity is one of the key problem of spread spectrum technology, and it is also the main contents of the paper. In addition, in order to improve anti-noise performance and network throughput of the system, combining the spread spectrum communication technology and the physical layer network coding, the physical layer network coding is applying network coding in the physical layer, which allows the signal from different source node merging in the sharing transmission channel, this reduced the complexity of wireless networks, and improved the interference ability of the system.In the design of the spreading sequence of this paper, drawing on the idea of complementary sequence, the potentially ideal autocorrelation and cross correlation properties of complementary sequences can effectively suppress multipath interference and multiple access interference, combined with the idea of zero correlation zone of quasi synchronous CDMA system and the idea of sequence pair, to further expand the optional space of spreading sequence.This paper firstly analyzes the related knowledge of sequence pairs, ZCZ sequence and the complementary sequence. On this basis, we studied two construction methods of ZCZ periodic complementary sequence pair set. The first method is interleaved construction method, the initial sequence of this method is periodic complementary sequence pair set, using interleaving technique and orthogonal matrix, constructed ZCZ periodic complementary sequence pair set with more number and more flexible length of zero correlation zone. The second method is overall interleaving iterative method, the initial sequence of this method is ZCZ sequence pair set, then constructing ZCZ periodic complementary sequence pair set based on overall interleaving iterative method, which were superior in the number and performance on traditional complementary sequence pairs set. The number and the length of zero correlation zone of ZCZ periodic complementary sequence pair set constructed at the N-th iteration is 2n times bigger than the initial sequence.Finally, in order to improve the reliability,the anti-noise performance of the system, and the throughput of the wireless network, we combine on the idea of network spreading codes(NSC), set the periodic complementary sequence pair as the spreading sequence, combine the spread spectrum communication and physical layer network coding, build a wireless communication network transmission system based on a combination of the two models, including PNSC-F system and PNSC-DSF system. We will encode and simulate on this basis, then study the BER performance. Simulation results show that in the AWGN channel, the PNSC-DSF system has a better BER performance, the BER performance is significantly better than traditional spread spectrum encoding and PNSC-F system.