Frequency domain concurrent channel equalization for multicarrier systems

Journal of the Brazilian Computer Society

Castro, Fernando C. C. de¹  Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, BRAZIL¹  D'Agostini, Fábio¹  Castro, Maria C. F. de¹  Carboni Júnior, Sirlesio¹ 

关键词: Concurrent;    Equalization;    Broadcast;    Modulation;    Pilots;    Multicarrier.;   

DOI  :  10.1590/S0104-65002007000100002

学科分类：农业科学（综合）

来源: Springer U K

【 摘 要 】

Receivers for wireless Orthogonal Frequency Division Multiplexing (OFDM) systems usually perform the channel estimation based on pilot carriers in known positions of the channel spectrum. Interpolation between pilot carriers is applied to determine the channel transfer function in all carrier frequencies. Channel variations along time are compensated by means of interpolation between successive channel estimates on the same carrier frequency. However, not rarely, the fast channel variations exceed the time interpolator capability, as is the case for mobile operation. In this article we present a new channel compensation technique based on the concurrent operation of two stochastic gradient time-domain algorithms, one which minimizes a cost function that measures the received signal energy dispersion and other which minimizes the Euclidean distance between the received digital modulation symbols and the ones in the reference constellation assigned to each OFDM sub-channel. Results show that the new technique advantageously improves the system robustness to fast channel variations since, with a low computational cost, it dramatically reduces the demodulator symbol error rate even when the receiver is operating in an intense dynamic multipath scenario.

【 授权许可】

Unknown