Performance of frequency domain sub-band diversity combination technique for wide-band mobile radio reception: An application to OFDM (Orthogonal Frequency Division Multiplexing) reception

Abstract

We have investigated a sub-band space diversity technique and assessed its potential application to wide-band mobile radio reception. By simulating the application of SB-SD to OFDM reception, the following main conclusions were reached. For DQPSK-OFDM reception in an equal-amplitude single-echo environment, substantially better echo resistance characteristics are obtained by applying MRC SB-SD than by using a time-offset, combination-type overall MRC-SD (i.e., WB-SD). When SB-SD is applied to DQPSK-OFDM reception in an equal-amplitude, single-echo environment and the spacing between receiving antenna branches is a half-wavelength (λ/2), diversity gains of about 20 dB for a two-branch configuration and 25 dB for antenna configurations with three or more branches are obtained at a BER of 2 × 10−3. The effectiveness of MRC SB-SD is demonstrated even when the delay time echo is longer than the OFDM guard interval. When SB-SD is applied to DQPSK-OFDM reception in a Rayleigh fading channel, diversity gains of about 17 dB for two-branch, 21 dB for three-branch, and 23 dB for four-branch configurations are obtained at a BER of 2 × 10−3. Bit error rates at Eb/N0 = 20 dB for D8PSK-OFDM reception in a Rayleigh environment are 2 × 10−2 for one-branch, 1 × 10−4 for two-branch, 1 × 10−4 for three-branch, and 1 × 10−5 for four-branch diversity. Bit error rates at Eb/N0 = 25 dB for D16PSK-OFDM reception in a Rayleigh environment are 2 × 10−2 for one-branch, 1 × 10−3 for two-branch, 1 × 10−4 for three-branch, and 1 × 10−5 for four-branch diversities. © 1998 Scripta Technica. Electron Comm Jpn Pt 1, 81(8): 32–41, 1998