DFT-S-OFDM Modulation Performance Based On Physical Layer Security And Wireless Sensor Network Application Analysis

As the next generation wireless communication rapid development in the direction of the broadband and fusion, the security threats they face are much more complicated and diversified. The traditional method of data security can not effectively protect the air interface and implement complexly, and it is difficult to meet the safety requirements of the next generation wireless communication. At present, the DFT-S-OFDM system has been widely applied to the next generation wireless communication, because of its advantages, such as good bandwidth utilization, high ability of resistance to multipath interference, low peak power ratio and low emission energy, etc.This paper proposes a new physical layer encryption algorithm by making full use of the characteristics of DFT-S-OFDM system. The algorithm takes the initial value of chaotic sequence as a seed key, and produces two complex diagonal matrix under its control, and then respectively multiplied the two matrix by the data before and after the N-point DFT transform. In this way, we finish the encryption process, and the algorithm is easy to implement. We theoretically proved that the algorithm does not change the PAPR of the original system, and analyzed the security of the algorithm when the subcarrier number N≥32. Theoretical analysis and simulation experiments show that the algorithm does not change the PAPR of the system, does not affect the bit error rate of the system; can resist exhaustion attack and cipher-text plaintext attack; and the algorithm is good to guarantee the security of data communication, in almost no increase in system implementation complexity.Combined with the complex application environment and the broadband demand of the developing wireless sensor networks, we design a physical layer transmission scheme of sensor node based on DFT-S-OFDM modulation. The program adopts DFT-S-OFDM modulation to replace the O-QPSK modulation defined in standard IEEE802.15.4PHY. Through the simulation and theoretical analysis, we determined the best parameters of DFT-S-OFDM modulation, N=16, M=32. This paper made an overall comparison between the performance of the DFT-S-OFDM modulation (N=16, M=32) scheme and the O-QPSK modulation in peak to average power ratio, bit error rate, implementation complexity, retransmission rates and bandwidth efficiency. The simulation results show that the DFT-S-OFDM modulation (N=16, M=32) scheme can improve the efficiency of communication between the sensor node.