Performance Analysis And Optimal Power Allocation For Multiuser Linear Network Coded Cooperation System

Linear network coded cooperation(LNCC)is a novel technology that combines linear network coding and cooperative communication.In wireless communications,it is a very important topic that how to improve the reliability,utilization and energy efficiency of communication under the constrains of available frequency spectrum and transmission power.In view of this,this thesis intensively studies the performance of multi-user LNCC system,based on which,this thesis further investigates the optimal power allocation for multi-user LNCC system.The detail work of this paper includes the following aspects:1.This paper analyzes the outage probability performance of the linear network coding model considering the path loss.We investigate the outage performance of a two-slot multiuser LNCC system in many-to-one communication mode.We fully consider the effect of path loss in the process of theoretical analysis and theoretically derive the tight approximated outage probability of LNCC system.And the analytic results are verified by Monte Carlo simulations.Numerical results show that two-slot LNCC system with path loss is able to greatly improve the outage performance.2.We investigate the optimal power allocation problem of the M-users linear network coding cooperation system.Based on the theoretical analysis on outage performance,this thesis further investigate energy efficient optimal power allocation(OPA)strategies for multiuser LNCC system.Two OPA strategies under different optimization criteria,i.e.,minimizing the total outage probability and minimizing the maximum outage probability under the constraint of total power available are proposed by utilizing genetic algorithm(GA).Numerical results demonstrate that the proposed OPA strategies do achieve the optimal power allocation and improve system's performance.In summary,the main contributions of this paper are summarized as follows:· We focus on the outage probability of a two-slot multiuser LNCC system with many-to-one communication pattern.We derive the tight approximated outage probability of this system considering path loss with Raleigh-fading channels.The effectiveness of our analytical framework has been verified by Monte Carlo simulations.· We propose two different power allocation strategies with the objectives of minimizing the total outage probability and minimizing the outage probabilities for all the users jointly under total power constraint by using genetic algorithm.To the best of our knowledge,this is the first work on OPA for multiuser LNCC system,especially for multi-objective OPA.