空載波對(duì)STBC-OFDM系統(tǒng)信道估計(jì)性能的影響分析與改進(jìn)

該文分析了空時(shí)分組碼-正交頻分復(fù)用(STBC-OFDM)系統(tǒng)中，空載波對(duì)基于離散傅里葉變換(DFT)信道估計(jì)的性能影響，推導(dǎo)得出空載波影響下信道估計(jì)均方誤差及誤碼率的解析式，并提出一種新的信道估計(jì)方法，通過(guò)時(shí)域乘以干擾因子矩陣的逆消除空載波引起的混疊，提高信道估計(jì)精度。仿真結(jié)果與理論結(jié)果相符，且表明改進(jìn)的信道估計(jì)算法有效消除均方誤差地板現(xiàn)象，提高系統(tǒng)性能。
關(guān)鍵詞：正交頻分復(fù)用；信道估計(jì)；空時(shí)分組碼；空載波

Abstract: Performance of Discrete Fourier Transform (DFT) based channel estimation for Space Time Block Code-Orthogonal Frequency Division Multiplexing (STBC-OFDM) systems with virtual subcarriers is analyzed.The concise expressions for Mean Squared Error (MSE) and corresponding Bit Error Rate (BER) with the effect of virtual subcarriers are provided. Besides, a new channel estimation method based on zero-forcing is presented to eliminate aliasing distortion caused by virtual subcarriers. Simulation results demonstrate the accuracy of the analysis and the efficiency of new method.Key words: Orthogonal Frequency Division Multiplexing (OFDM); Channel estimation; Space Time Block Code (STBC); Virtual subcarriers