Variable-Rate Two-Phase Collaborative Communication Protocols for Wireless Networks

Dept. of Electr. & Comput. Eng., Yokohama Nat. Univ.
IEEE Transactions on Information Theory (Impact Factor: 2.33). 10/2006; 52(9):4299 - 4313. DOI: 10.1109/TIT.2006.880055
Source: IEEE Xplore

ABSTRACT The performance of two-phase collaborative communication protocols is studied for wireless networks. All the communication nodes in the cluster are assumed to share the same channel and transmit or receive collaboratively in a quasi-static Rayleigh flat-fading environment. In addition to small-scale fading, the effect of large-scale path loss is also considered. Based on a decode-and-forward approach, we consider various variable-rate two-phase protocols that can achieve full diversity order and analyze the effect of node geometry on their performance in terms of the outage probability of mutual information. For the single-relay node case, it is shown that if the collaborator node is close to the source node, a protocol based on space-time coding (STC) can achieve good diversity gain. Otherwise, a protocol based on receiver diversity performs better. These protocols are also compared with one based on fixed-rate repetition coding and their performance tradeoffs with node geometry are studied. The second part deals with multiple relays. It is known that with N relays an asymptotic diversity order of N+1 is achievable with STC-based protocols in the two-phase framework. However, in the framework of collaborative STC, those relay nodes which fail to decode remain silent (this event is referred to as a node erasure). We show that this node erasure has the potential to considerably reduce the diversity order and point out the importance of designing the STC to be robust against such node erasure

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    • "Calculation of P S k R m (e): The probability of error in the S k → R m link P S k R m (e) can be calculated following the similar steps used for the calculation of P k (e|A k ). An upper bound for P S k R m (e) can be calculated by using the union bound [16] "
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    ABSTRACT: In this paper, we investigate the performance of a cooperative orthogonal frequency-division multiple-access (OFDMA) system with decode-and-forward (DaF) relaying. Specifically, we derive a closed-form approximate symbol-error-rate expression and analyze the achievable diversity orders. Depending on the relay location, a diversity order up to $(L_{S_{k}D} + hbox{1}) +break sum_{m = 1}^{M}min(L_{S_{k}R_{m}} + hbox{1}, L_{R_{m}D} + hbox{1})$ is available, where $M$ is the number of relays, and $L_{S_{k}D} + hbox{1}$, $L_{S_{k}R_{m}} + hbox{1}$, and $L_{R_{m}D} + hbox{1}$ are the lengths of channel impulse responses of source-to-destination, source-to- $m$th relay, and $m$th relay-to-destination links, respectively. Monte Carlo simulation results are also presented to confirm the analytical findings.
    IEEE Transactions on Vehicular Technology 06/2014; 63(5):2216-2223. DOI:10.1109/TVT.2013.2290780 · 1.98 Impact Factor
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    • "where í µí°¾ is a constant that depends on the environment, and í µí¼€ is the path-loss exponent [14]. For free space path loss, this paper considers í µí¼€ = 2 and í µí°¾ = í µí°º í µí±¡ í µí°º í µí±Ÿ í µí¼† "
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    • "SER cooperation via relaying has drawn much interest recently to enhance the throughput and the reliability of wireless communications [1]–[3]. While several research results [4]–[9] are oriented toward improving the throughput, others [10]–[13] try to enhance the reliability of the wireless channels using the relay. The relation between the reliability and the throughput in the MIMO channels is captured in the diversity-multiplexing trade-off (DMT) analysis of [14]. "
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