Design space–time trellis-coded intercarrier interference parallel cancelation architectures for ofdm systems

Abstract

Space-time (ST) coding combined with orthogonal frequency-division multiplexing (OFDM) is a robust transmission system. However, ST-OFDM system performance may degrade because of the intercarrier interference (ICI) in frequency-selective fading channels. To mitigate the ICI, a parallel cancelation (PC) algorithm is employed and combined with a 2 × 1 ST code to form an STPC-OFDM system. Further developing the idea of the STPC-OFDM system, we design a modified ST trellis-coded (STTC)-ST-OFDM system and the novel STTC-STPC-OFDM architecture and algorithms to mitigate ICI without expending power or bandwidth or significant complexity. Since this new system integrates ICI PC with channel coding gain and diversity gain, its bit-error-rate performance is better compared with the STPC-OFDM system with a lower error floor in frequencyselective mobile fading channels. Moreover, the Walsh-Hadamard (WH) transformation is further applied to the STTC-STPCOFDM system to form a novel STTC-WH-STPC-OFDM architecture and improve the overall system performance significantly with the same data rate, same power, and same complexity as that of STTC-STPC-OFDM systems.