Upper and lower bounds on peak-to-mean envelope power ratio (PMEPR) in OFDM systems are derived in this paper. The derivation results show that the upper bound on PMEPR only depends on the aperiodic autocorrdation fun...Upper and lower bounds on peak-to-mean envelope power ratio (PMEPR) in OFDM systems are derived in this paper. The derivation results show that the upper bound on PMEPR only depends on the aperiodic autocorrdation functions of the data sequences and is quite useful for rapid elimination of sequences that have PMEPR exceeding a given threshold. According to the lower bound on PMEPR,it has a great change as N (number of subcarriers) varies only for a very small N. For a 16-subcarrier BPSK-OFDM system, a selective mapping (SLM) way to reduce PMEPR is investigated with the upper bound on PMEPR and the distribution of PMEPR for all possible message sequences is given. The analytic results show that the maximal PMEPR is about 6.5 dB which is 5.5 dB less than that in worst situation.展开更多
正交时频空(Orthogonal Time Frequency Space,OTFS)是一种支持在强多普勒环境中进行信息可靠传输的调制技术。该技术应用于雷达通信一体化系统中,对峰值旁瓣比和包络峰均比进行联合抑制,实现正交时频空雷达通信一体化波形的优化设计。...正交时频空(Orthogonal Time Frequency Space,OTFS)是一种支持在强多普勒环境中进行信息可靠传输的调制技术。该技术应用于雷达通信一体化系统中,对峰值旁瓣比和包络峰均比进行联合抑制,实现正交时频空雷达通信一体化波形的优化设计。分析了正交时频空雷达通信一体化信号的模糊函数以及通信信息对其的影响。通过伪随机序列对通信信息进行扩频,进而优化模糊函数的峰值旁瓣比,联合迭代限幅滤波技术来降低一体化信号的包络峰均比。仿真结果表明,所提算法可以在抑制峰值旁瓣比的同时使得包络峰均比也得到降低,具有较好的雷达通信一体化性能。展开更多
文摘Upper and lower bounds on peak-to-mean envelope power ratio (PMEPR) in OFDM systems are derived in this paper. The derivation results show that the upper bound on PMEPR only depends on the aperiodic autocorrdation functions of the data sequences and is quite useful for rapid elimination of sequences that have PMEPR exceeding a given threshold. According to the lower bound on PMEPR,it has a great change as N (number of subcarriers) varies only for a very small N. For a 16-subcarrier BPSK-OFDM system, a selective mapping (SLM) way to reduce PMEPR is investigated with the upper bound on PMEPR and the distribution of PMEPR for all possible message sequences is given. The analytic results show that the maximal PMEPR is about 6.5 dB which is 5.5 dB less than that in worst situation.
文摘多载波相位编码(multicarrier phase-coded,MCPC)信号作为一种宽带雷达信号,由于具有高频谱利用率,良好的抗干扰能力和调制解调简单等优势而在近几年备受瞩目。但MCPC信号具有较大的包络起伏,这对雷达内部功率放大器的线性动态范围提出极高要求。本文首先针对MCPC信号包络起伏大这一主要缺点,对MCPC雷达信号进行建模并分析信号特点,使用遗传算法,对MCPC雷达信号子载波权重进行调节,该算法在满足功率约束前提下,可得到具有较低包络峰均功率比(peak-to-mean envelope power ratio,PMEPR)的优化信号;然后进一步将满足要求的低PMEPR值设为约束,对MCPC信号自相关旁瓣进行抑制。仿真实验结果表明该方法能在有效降低MCPC的包络峰均比的同时,使发射信号具有良好的自相关特性,优化方法具有实际应用价值。
文摘正交时频空(Orthogonal Time Frequency Space,OTFS)是一种支持在强多普勒环境中进行信息可靠传输的调制技术。该技术应用于雷达通信一体化系统中,对峰值旁瓣比和包络峰均比进行联合抑制,实现正交时频空雷达通信一体化波形的优化设计。分析了正交时频空雷达通信一体化信号的模糊函数以及通信信息对其的影响。通过伪随机序列对通信信息进行扩频,进而优化模糊函数的峰值旁瓣比,联合迭代限幅滤波技术来降低一体化信号的包络峰均比。仿真结果表明,所提算法可以在抑制峰值旁瓣比的同时使得包络峰均比也得到降低,具有较好的雷达通信一体化性能。
