Optimal resource allocation in OFDM-based multihop cooperative networks

Abstract

The demand for high data rate, power and spatial efficiency in mobile communication has been grown rapidly. ODFM, a digital multi-carrier modulation method, which has been widely adopted in digital subscriber lines, WLANs (802.11a/g/n), WiMAX and even the LTE, can conquer the data rate constraint caused by multipath channel and therefore can achieve high data rate in wireless channel. Due to the broadcast nature of wireless communication, the cooperation between mobile devices would be possible and some benifits such as diversity gain and power efficiency can be achieved. In this project, an OFDM-based multi-hop cooperative network is investigated with aim to find the optimal resource allocation in it. The resources include the OFDM subcarriers, power, number of hops and number of relays in each hop.The outage probability is chosen as the performance criteria. For the allocation of subcarriers and relays, the OFDMA (The multi-user version of ODFM, allow individual subcarrier has its own routing path) selective relaying is suggested. The process of selecting relay in each hop is performed for each subcarrier independently. Power is equally distributed in each hop and how many hops should be use to make the total outage probability minimum is investigated.