User Cooperation in TDMA Wireless System

Abstract: Reliability of radio link is limited, owing to path loss, shadowing and multi-path fading. This necessitates the use of a certain type of diversity. In recent years, cooperative diversity has gained considerable attention. Here, wireless nodes cooperate in such a way that they share their antennas and other resources, to create a virtual array through distributed transmission and signal processing. This increases coverage and reduces transmitted power, thereby bringing down co-channel interference, which results in increased system capacity. This paper gives an overview of the state of art of various cooperation schemes and issues related to their implementation

The SER Analysis of Rayleigh, Rician and Nakagami Channels at Various Relay Locations in Cooperative Networks

Reliable communication between transmitter and receiver is accomplished by cooperative diversity techniques. Sending of data in various paths has greatly improved the performance of communication. We have studied the performance of Amplify-and-Forward (AF) based network in this work for diverse relay location at Nakagami, Rician and Rayleigh fading channels. The relay performance in Amplify-and-Forward (AF) protocol based on Symbol Error Rate (SER) against Signal-to-Noise Ratio (SNR) in dBs is calculated. The software that is used to construct Monte-Carlo link level simulation is MATLAB. The effects of a relay at changed location in diverse channels accompanied with Additive White Gaussian noise (AWGN) is also calculated. BPSK modulation scheme is used for the transfer of information between the source, relay and destination node. The signals are combined through Maximum Ratio Combining method (MRC).Reliable communication between transmitter and receiver is accomplished by cooperative diversity techniques. Sending of data in various paths have greatly improved the performance of communication. We have studied the performance of Amplify-and-Forward (AF) based network in this work for diverse relay location at Nakagami, Rician and Rayleigh fading channels. The relay performance in Amplify-and-Forward (AF) protocol based on Symbol Error Rate (SER) against Signal-to-Noise Ratio (SNR) in dBs is calculated. The software that is used to construct Monte-Carlo link level simulation is MATLAB. The effects of relay at changed location in diverse channels accompanied with Additive White Gaussian noise (AWGN) is also calculated. BPSK modulation scheme is used for the transfer of information between the source, relay and destination node. The signals are combined through Maximum Ratio Combining method (MRC)

Energy-delay bounds analysis in wireless multi-hop networks with unreliable radio links

Energy efficiency and transmission delay are very important parameters for wireless multi-hop networks. Previous works that study energy efficiency and delay are based on the assumption of reliable links. However, the unreliability of the channel is inevitable in wireless multi-hop networks. This paper investigates the trade-off between the energy consumption and the end-to-end delay of multi-hop communications in a wireless network using an unreliable link model. It provides a closed form expression of the lower bound on the energy-delay trade-off for different channel models (AWGN, Raleigh flat fading and Nakagami block-fading) in a linear network. These analytical results are also verified in 2-dimensional Poisson networks using simulations. The main contribution of this work is the use of a probabilistic link model to define the energy efficiency of the system and capture the energy-delay trade-offs. Hence, it provides a more realistic lower bound on both the energy efficiency and the energy-delay trade-off since it does not restrict the study to the set of perfect links as proposed in earlier works

Integrated Satellite-Terrestrial System Capacity Over Mix Shadowed Rician and Nakagami Channels

In this paper, we evaluate the ergodic capacity analysis of a integrated satellite-terrestrial cooperative communication system under independent and non-identical shadowed Rician and Nakagami-m fading channels. Multiple cooperative relay nodes are assumed between satellite and the destination node. Amplify-and-forward (AF) cooperative protocol is used at each fixed relay node for signal amplification. While for signals combining at the destination node, the maximum ratio combining(MRC) technique is exploited. An analytical approach is derived to evaluate the performance of the system in terms of ergodic capacity. We derive the approximate closed-form expression for calculating the ergodic capacity of the proposed system. It is shown that the derived analytical expression is very tight and applicable to the general operating conditions with the help of satellite channel date available from the literature. The analytical results are compared with Monte Carlo simulations, and they seem to agree well