A Simple and Robust Equalization Algorithm for Variable Modulation Systems

Electronics

Ruru Mei¹  Wanru Hu¹  Zhugang Wang¹  Meiyan Lin¹ 

[1] Key Laboratory of Electronics and Information Technology for Space System, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China;

关键词: variable modulation (VM) systems;    mode switching;    inter-symbol interference (ISI);    data-assisted equalization algorithm;    variable modulation-decision-directed least mean square (VM-DDLMS) algorithm;   

DOI  :  10.3390/electronics10202496

来源: DOAJ

【 摘 要 】

This paper proposes a simple and robust variable modulation-decision-directed least mean square (VM-DDLMS) algorithm for reducing the complexity of conventional equalization algorithms and improving the stability of variable modulation (VM) systems. Compared to conventional adaptive equalization algorithms, known information was used as training sequences to reduce the bandwidth consumption caused by inserting training sequences; compared with conventional blind equalization algorithms, the parameters and decisions of the equalizer were determinate, which was conducive to a stable equalization performance. The simulation and implementation results show that the proposed algorithm has a better bit error rate (BER) performance than that of the constant modulus algorithm (CMA) and modified constant modulus algorithm (MCMA) while maintaining the same level of consumption of hardware resources. Compared to the conventional decision-directed least mean square (DDLMS) algorithm, the proposed algorithm only needs to make quadrature phase shift keying (QPSK) symbol decisions, which reduces the computational complexity. In parallel 11th-order equalization algorithms, the operating frequency of VM-DDLMS can reach up to 333.33 MHz.

【 授权许可】

Unknown