PERFORMANSE EVALUATION OF CODED COOPERATION USING RCPC AND RCPT CODES

Abstract

Coded Cooperation is a burgeoning field of Cooperative Communications. This generates diversity in a new and interesting way. This method integrates cooperation into channel coding. Coded Cooperation allows single antenna systems to reap some of the benefits of multi input multi output (MIMO) systems without using multiple antennas. Cooperative Communication allows single-antenna mobiles to reap some of the benefits of MIMO systems. The basic idea is that single-antenna mobiles in a multi-user scenario "share" their antennas in a manner that creates a virtual MIMO system. The mobile wireless channel suffers from fading, i.e., the signal attenuation can vary significantly over the course of a given transmission. Coded Cooperation is the cost effective way to achieve spatial diversity. Coded Cooperation framework can be implemented using block or convolutional codes. A simple and effective implementation of Coded Cooperation can be done using rate compatible punctured convolutional codes (RCPC). This provides better performance than Amplify and Forward (AF) and Detect and Forward (DF) schemes. This Coded Cooperation can be applied to the wireless networks where more than two users cooperate to transmit their data. By changing the cooperation percentages according to the channel conditions, users will achieve performance gains. The alternative to implement Coded Cooperation other than RCPC Codes comes in the form of RCPT Codes. RCPT Codes performs better than RCPC Codes in terms of error correction. In this dissertation work, we proposed Coded Cooperation using RCPT codes in case of two users and multiple users to achieve better BER performance than RCPC Coded Cooperation. Coded Cooperation partitions the user's code word into frames which are transmitted via independent fading paths. Formation of number of frames will depend on the number of users participating in cooperation. For an M-user cluster each user will divide his data frame into `M' number of frames for cooperation. In this work, frames are formed using puncturing. In case of RCPC Coded Cooperation, Viterbi decoder is used at the users and also at the Base Station. For RCPT Coded Cooperation, Viterbi decoder is used at the users whereas Iterative Turbo decoder is used at the Base station. MATLAB environment is used for our simulations.