Relay Mode Selection And Resource Allocation For Multicarrier Networks

With the development of wireless communication techniques,spectrum resource is becoming increasingly scarce.How to use the resource effectively is a technical problem necessary to be solved.Multicarrier,as an effective method to increase the whole transmission bandwidth,is able to improve spectrum efficiency;Two-way relaying,enabled by network coding techniques,also improves spectrum efficiency when compared with the traditional one-way relaying;Compared with half duplex which can only transmit or receive signals in a time slot,the full duplex,able to transmit and receive signals at the same time,is more spectrum efficient;What's more,cognitive radio is another new communication paradigm to improve spectrum utilization.Therefore,combining the aforementioned techniques has the potential to fully exploit the benefits of them to further improve spectrum efficiency.This dissertation studies the relay mode selection and resource allocation for multicarrier networks.Firstly,the dissertation studies the relay duplex mode selection and power allocation for a multicarrier network.A classic three-node relay network is studied.And a unified signal model is proposed to represent four typical relay modes.Then,basing on the unified signal method,a joint relay mode selection and power allocation method is developed.At last,the dissertation carries out numerical experiments to verify the performance of the proposed scheme.Then,the dissertation studies the relay transmission mode selection and resource allocation for a multicarrier-based cognitive network.Cognitive two-way relaying has been investigated,and the licensed spectrums are divided into a number of subchannels.What's more,the secondary node can operate assistant transmission and cognitive transmission.A joint spectrum partition,subchannel permutation,and power allocation problem is proposed.The problem is then transformed and solved.Further,it is verified that,for the optimal solution,the relay transmission mode on each subcarrier can only be one of the two transmission modes,namely,assistant transmission and cognitive transmission.At last,numerical experiments verify the performance of the proposed method and the validity of the conclusion.Finally,the dissertation studies sum rate balancing and power allocation for a multicarrier-based cognitive network.A cognitive radio network is investigated,in which OFDM-based two-way relaying is used in the secondary system.An optimal scheme for power allocation is presented to maximize the smaller data rate of the secondary users.Furthermore,a distributed power allocation algorithm is proposed.The performance of the proposed scheme is illustrated by numerical simulations and comparisons.