| Cooperative diversity, enabled by communicators willing to collaborate, offers an effective means of mitigating slow fading propagation effects. Early repetition-based single-source cooperative (SSC) schemes incur severe rate loss. By allowing joint encoding of messages from multiple sources, the recent multi-source cooperative (MSC) protocols provide higher diversity and code rate relative to the SSC counterparts.;This dissertation develops distributed coding schemes for MSC networks, including distributed convolutional codes (DCC), distributed trellis coded modulation (DTCM), distributed complex field codes (DCFC), and a general framework for MSC networks. Different protocols have different advantages. DCC is particular appealing for its low-complexity optimal decoder. However, carefully designed interleavers are required to achieve maximum possible diversity in DCC protocols. DTCM enables identical bandwidth efficiency to noncooperative networks while being able to effect higher diversity. In an MSC network with K users, both DCC and DTCM are impossible to achieve full diversity with rate R > 1/K for binary transmissions. The DCFC protocol in MSC networks achieve full diversity K, regardless of the underlying constellation. A joint error control codes and DCFC approach further improves system coding gain. The general framework with hybrid TDMA and CDMA includes many protocols, eg., DCC and DCFC, as special cases. By adjusting the number of cooperating users, MSC encoder, spreading gain, and/or the number of clusters, this framework offers a flexible tradeoff among spectral-efficiency, decoding complexity, and diversity.;This dissertation also includes two topics related to decoding at the destination. The first topic is CRC assisted error correction in a convolutionally coded system. By exploiting the structure of CRC, error performance is improved with iterative log-map (ILM) and soft decision syndrome decoding (SDSD) algorithms. The second topic is on soft multi-input multi-output detection. With a soft-to-hard conversion at the decoder, a novel soft decision based hard sphere decoding (SoD-HSD) algorithm enables near-capacity performance. Future research includes the study of outage capacity of MSC networks. |
