Research On New Decoding Method Of CTC Under Strong Interference

Along with the further development of network technology,the wireless communication devices working in ISM band are growing exponentially,which makes the interference problem between various devices more and more serious.To alleviate this problem,Cross-Technology Communication(CTC)technology has emerged.In the existing Wi-Fi to Zig Bee physical layer CTC method,the error has to be tolerated by increasing the decoding threshold due to the large simulation error.However,the excessive increase of decoding threshold will lead to the Zig Bee receiver cannot work properly in the strong interference environment,and the existing CTC can solve the anti-interference problem only through multiple retransmissions.To address the above problems,this paper proposes a CTC communication system without retransmission,strong interference immunity,high throughput,low bit error rate,and taking into account CTC and traditional Zig Bee communication,which is named Strong Bee in this paper.The main research work of this paper is as follows.First,to address the simulation error problem caused by the cyclic prefixes of existing physical layer CTC methods,the Strong Bee sender reduces the error by cleverly constructing a predefined cyclic prefix.This method copies the expected cyclic prefix designed in advance to the end of each CTC symbol,which results in 4 bits of error information reduction per emulated Zig Bee symbol.Second,Strong Bee designed a new Zig Bee decoding method to address the problem that the existing CTC method had high decoding thresholds that prevented Zig Bee receivers from working properly under strong interference.By using the existing chip error location and probability distribution,the chips with the error probability up to 80%are inverted bit-reverse,and the chips with the error probability lower than 20% remain unchanged.Through this enhanced design,the anti-interference performance of the receiver is significantly enhanced.Again,using the Enhanced Symbol-Chip Mapping(ESCM)table proposed in this paper,Strong Bee designes a new preamble identification algorithm based on the minor differences between CTC preamble and Zig Bee preamble.This method enables Strong Bee to receive both CTC and Zig Bee packets.Finally,this paper builds a system model based on GNU Radio platform,USRP N210 and CC2531 to make tests on Strong Bee related performance under different scenarios.The test results show that Strong Bee greatly optimizes the CTC process from Wi-Fi to Zig Bee at the physical layer level.It is resistant to interference and has a throughput of up to 220 Kbps without retransmission technology,which improves frame reception rate and reduces bit error rate,meanwhile Strong Bee is transparent to 802.15.4 protocol.