Fast-decodable space-time block code designs for wireless communications

Over the last decade, space-time block code (STBC) designs have been under a significant consideration since they can fully explore the spatial diversity to improve the transmission reliability in multiple-input multiple-output (MIMO) systems. The performance of a full-diversity STBC design is determined by the tradeoff between code rate and decoding complexity. This thesis focuses on how to deal with the tradeoff in full-diversity STBC designs for various wireless communication systems. The aim of the research is to develop full-diversity and fast-decodable STBC designs to improve the transmission reliability in wireless communications.In MIMO systems, partial interference cancellation (PIC) group decoding is capable of well addressing the rate and complexity tradeoff. In this thesis, a multi-layer STBC is firstly proposed under the PIC group decoding. Then, a systematic STBC design is proposed by using coordinated interleave orthogonal design (CIOD), which can admit the lowest complexity under the PIC group decoding without loss of code rate.MIMO orthogonal frequency division multiplexing (MIMO-OFDM) is one of promising technologies to support more reliable transmission over frequency-selective fading channels. Space-frequency code (SFC) designs were proposed to achieve spatial and frequency diversity in the systems. However, most space-frequency code designs suffer from either the low code rate or the high decoding complexity. To address the tradeoff, a design criterion is proposed for an SFC to achieve full diversity under the PIC group decoding. Based on the criterion, this thesis proposes a systematic full-diversity SFC design.Compared with conventional relay networks, two-path successive relay (TPSR) network is attractive due to a higher spectral efficiency. In this thesis, a fast-decodable distributed STBC for TPSR network is proposed that achieves both full diversity and full transmission rate.In wireless networks, one of the major concerns is transmission reliability in two-user interference channels. How to suppress inter-user interference without side impact on the transmission reliability is an open topic. In this thesis, a design criterion is proposed for an STBC to achieve full diversity in two-user MIMO interference channels without channel information at transmit side (CSIT). Then, a systematic STBC design is proposed to obtain full diversity after interference cancellation