http://idl-bnc.idrc.ca:80/dspace/handle/10625/46772 2013-05-23T18:25:54Z http://idl-bnc.idrc.ca:80/dspace/handle/10625/49057 Title: Performance Analysis of a Multi-Relay Cooperative Diversity Network with Decode and Forward Relaying Authors: Selvaraj, M D; Mallik, R K Abstract: Consider a multi-relay cooperative diversity network consisting of a source, N relays, and a destination. For the transmission of a data symbol from the source to the destination, the re- lays cooperate with the source through the decode and forward protocol. All the links are statisti- cally independent and undergo flat Rayleigh fad- ing. Conventional instantaneous signal-to-noise ratio based selection combining at the destina- tion chooses one link from the set consisting of the source-to-destination link and the N relay-to- destination links. However, this scheme does not account for the effect of the source-to-relay links in the error performance. To overcome this draw- back, we present here a scaled selection combining scheme, which accounts for this effect through a deterministic scale factor. The end-to-end symbol error probability (SEP) of this scheme with binary phase-shift keying is derived in closed form. We also give a method of obtaining the optimum scale factor that minimizes the end-to-end SEP. Description: 2010 National Conference on Communications (NCC) 2010-01-01T00:00:00Z http://idl-bnc.idrc.ca:80/dspace/handle/10625/49043 Title: Performance Analysis of a Multi-Hop Communication System with Decode-and-Forward Relaying Authors: Dhaka, Kalpana; Mallik, Ranjan K; Schober, Robert Abstract: This paper analyzes the performance of a multi-hop wireless communication system, consisting of a source node, N intermediate nodes or relays, and a destination node in a Rayleigh fading environment with decode-and-forward relaying at each intermediate node. The data is therefore transmitted from source to destination through N + 1 hops. Two types of modulation, namely, M-ary phase-shift keying (MPSK) and orthogonal M-ary frequency-shift keying (OMFSK), are considered for the transmitted data. In case of MPSK, each relay performs coherent detection, while in case of OMFSK, each relay performs noncoherent detection. Using a difference equation approach, analytical expressions for the end-to-end symbol error probability are derived in both cases. We find that (1) although the performance degrades with increasing number of hops for fixed average signal-to-noise ratio per hop, the incremental degradation in performance with the addition of each extra hop decreases, (2) when each node transmits with fixed power, multi-hop transmission offers significant performance improvement over direct transmission. Description: This full text paper was peer reviewed at the direction of IEEE Communications Society subject matter experts for publication in the IEEE ICC 2011 proceedings; This paper appears in the 2011 IEEE International Conference on Communications(ICC) 2011-07-28T00:00:00Z http://idl-bnc.idrc.ca:80/dspace/handle/10625/49023 Title: Analysis and Design of Cooperative BICM-OFDM Systems Authors: Islam, Toufiqul; Schober, Robert; Mallik, Ranjan K; Bhargava, Vijay K Abstract: In this paper, we propose a novel cooperative diversity scheme for wireless systems employing the combination of bit–interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). The proposed scheme utilizes an amplify–and–forward protocol where relays are assigned to multiple groups. Relays in the same group transmit concurrently over disjoint sets of sub–carriers and relays in different groups transmit in different time slots. We derive closed–form expressions for the asymptotic worst–case pairwise error probability and the diversity gain of the proposed cooperative BICM–OFDM scheme. Based on the derived analytical results we develop design guidelines for sub–carrier allocation, relay grouping, and relay selection. Simulation results corroborate the derived analytical results and confirm the effectiveness of the developed optimization framework. 2011-06-01T00:00:00Z