Analysis of DMT in multi-user wireless network using orthogonal, non-orthogonal and cluster MDS FFNC

In this paper, a new method is proposed to improve the diversity order of the wireless network to combat the fading in the channel. The network is assumed to have multiple sources, multiple relays, and one common destination. The relay in the network is assumed to use the `decode and forward´ protocol. The relay, with binary network code (BNC), to transmit the message from source to destination, the network achieves the diversity order of K with K relays. The network is proposed with finite field network code (FFNC) with orthogonal transmission i.e., each user transmit the message in single time slot and it is termed as orthogonal Minimum Distance Separable (MDS) FFNC protocol. Instead of separately retransmitting each source message, if the relay employs a class of spectrally efficient FFNC codes to assist the sources, it is termed as non orthogonal MDS FFNC protocol. Fully orthogonal or fully non orthogonal transmission among sources/ relays does not necessarily provide optimized Diversity Multiplexing tradeoff (DMT) performance. Thus, the transmission protocol that divides the sources and relays into individual clusters, termed as cluster MDS FFNC, is proposed. The nodes within one cluster transmit non- orthogonally while the transmissions of different cluster span orthogonal channels. The DMT for orthogonal, non orthogonal and clustering strategies are compared.