Order-4 Quasi-Orthogonal Cooperative Communication in STFC MB-OFDM UWB

Recently, cooperative communication and Space-Time-Frequency-Codes (STFCs) have been introduced into the Multiband OFDM Ultra-Wideband (MB-OFDM UWB) to improve the reliability, data rate and system capacity. This paper proposes a cooperative communication scheme for a four source node MB-OFDM UWB system using Quasi-Orthogonal STFCs, which is referred to as order-4 Quasi-Orthogonal Cooperative Communication Scheme (4-QOCCS). Simulation results show that the proposed 4-QOCCS provides significantly better error performance over the conventional MB-OFDM UWB and our order-2 Orthogonal Cooperative Communication Scheme (2-OCCS) using the Alamouti STFCs, and even better than the order-4 Orthogonal Cooperative Communication Scheme (4-OCCS), which we have been recently proposed, in the high spectral efficiency cases.