Cooperative diversity is an attractive new way to increase throughput, reduce energy requirements and provide resistance to channel fading effects in wireless networks. Because of its distributed nature, this new approach to spatial diversity allows a network of relatively simple, single

with more than one relay loses about half of the diversity order of AF. Index Terms — Modulation, cooperative diversity, fading, biterror rate (BER), relay channel.

results and to provide detailed performance comparisons among the three relaying techniques under consideration. Index Terms—Cooperative diversity, space-time block coding, multiple antennas, fading channels, pairwise error probability. I.

We consider a wireless network, which consists of several active source/destination pairs and a number of idle nodes. Multiple idle nodes volunteer as relays to facilitate the communication. All nodes have low mobility and the fading channel is essentially constant over the latency time scale

as an indirect signal from one of the available relays. The relays rebroadcast the transmissions in order to achieve diversity at the receiver. Both amplify-and-forward and decode-and-forward relay networks are considered. Channels are modeled with Rayleigh fading, path loss, and additive white Gaussian noise

analysis, in practice the underlying channels in broadband wireless communication systems such as cellular systems (UMTS/LTE) are more likely to exhibit frequency selective fading. In this dissertation, we con-sider a frequency selective fading channel model and explore distributed diversity techniques

In this paper, we present a simplified scheduling scheme for packet transmission over a fading channel which is modeled as a finite state block channel. We first derive the optimal minimum power transmission policy with constraints on both average delay and packet loss. This problem is seen

. As an alternative to various error-control coding techniques that have been proposed to ameliorate the problem, we perform complex-field coding (CFC) before the symbols are multiplexed. We quantify the maximum achievable diversity order for independent and identically distributed (i.i.d.) or correlated Rayleigh-fading

single opportunistic relay. Numerical and simulation results are presented to verify our analysis. Index Terms — Cooperative diversity, fading relay channel, outage probability, wireless networks. I.

Wireless communication now has been focus to increase data rate and high performance. The multi carrier on multi-hop communication system using relay's diversity technique which is supported by a reliable coding is a system that may give high performance. This research is developing a model