WRAN系统中基于自适应内插的信道估计算法

Adaptive Interpolation Based Channel Estimation for WRAN System

提出了一种基于自适应复系数内插的信道估计算法,改善了无线区域网络(WRAN)系统对抗动态多径时延的能力。WRAN是第一个采用认知无线电技术改善频谱效率的宽带接入标准,系统在下行链路中采用了正交频分复用(OFDM)调制技术,而信道估计技术对于采用相干解调的OFDM系统十分重要。传统的OFDM信道频域响应(CFR)估计算法通常采用实系数频域内插的方式,在对抗WRAN系统长多径时延信道时,不能有效地工作。该文在研究实系数FIR内插变换域响应的基础上,提出了一种复系数内插算法。为了同时适用于短时延信道,提出了一种低复杂度、自适应匹配信道最大多径时延的算法。通过仿真,验证了该算法能够对抗更大的多径时延,提高信道估计的精度,改善系统误码性能。

A channel estimation algorithm based on adaptive complex coefficient interpolation is proposed for improving the ability to combat muhipath delay of wireless regional area network （WRAN） system greatly. WRAN is the first broadband access standard to improve the spectrum efficiency by making use of cognitive radio technology. Orthogonal frequency divi- sion multiplexing （OFDM） is used in the downlink of the WRAN system in which channel estimation is very important for the coherent demodulation of OFDM system. However, traditional channel frequency response estimation algorithms, which adopt real-coefficient are sensitive to long-delay echoes in muhipath channels. According to transform domain response of real coefficient finite impulse response （FIR） interpolation, a complex coefficient interpolation algorithm is derived in this paper. In order to apply to short delay channel simultaneously, a low-complexity algorithm adaptively matching channel maximum multipath delay is proposed. Then the estimation performance is investigated and simulated. Experimental results verified the theoretical analysis and the validity of the proposed scheme.