Symbol Error Rate of Space-Time Network Coding in Nakagami-m Fading

In this paper, we analyze the symbol error rate (SER) of space-time network coding (STNC) in a distributed cooperative network over independent but not necessarily identically distributed (i.n.i.d.) Nakagami-$m$ fading channels. In this network, multiple sources communicate with a single destination with the assistance of multiple decode-and-forward (DF) relays. We first derive new exact closed-form expressions for the SER with $M$-ary phase shift-keying modulation ($M$-PSK) and $M$-ary quadrature amplitude modulation ($M$-QAM). We then derive new compact expressions for the asymptotic SER to offer valuable insights into the network behavior in the high signal-to-noise ratio (SNR) regime. Importantly, we demonstrate that STNC guarantees full diversity order, which is determined by the Nakagami-$m$ fading parameters of all the channels but independent of the number of sources. Based on the new expressions, we examine the impact of the number of relays, relay location, Nakagami-$m$ fading parameters, power allocation, and nonorthogonal codes on the SER.Comment: 23 pages, 9 figure

Outage Probability of Overhearing Amplify-and-Forward Cooperative Relaying

This paper investigates the outage performance of overhearing amplify-and-forward (AF) cooperative relaying, where a source transmits information to its destination through multiple helping overhearing AF relays with space-time network coding (STNC) employed. Firstly, the transmission protocol of such a relaying system, i.e., cooperative relaying with overhearing AF relays based on STNC (STNC-OHAF) is presented. Then, the instantaneous end-to-end SNR expression of STNC-OHAF is analysed. Based on this, an explicit expression of the outage probability for STNC-OHAF over independent but not necessarily identically distributed (i.n.i.d) Rayleigh fading channels is theoretically derived. Numerical results validate our theoretical analysis and show that by introducing overhearing among relays, the outage performance of the system can be greatly improved. It also shows that there is a trade-off between system sum outage capacity and the transmitted number of symbols.Comment: 4 pages, 3 figures, submitted to ELECTRONICS 201