Resource allocation in multichannel broadband wireless systems

Orthogonal Frequency Division Multiplexing (OFDM) has been used to combat inter symbol interference in broadband wireless systems. The available broadband channel has been divided into many narrow subbands. Channel aware resource allocation can be used to allocated each subchannel to the appropriate user and improve spectral efficiency and quality of service. OFDM provides multi user diversity but has one disadvantage, which is high Peak to Average Power Ratio (PAPR), which decreases energy efficiency of mobile terminals. One solution is a method which has the same overall complexity with OFDM, and is called Single Carrier Frequency Division Multiplexing (SC-FDM). SC-FDMA has unique resource allocation constraints, which makes the channel allocation problem interesting. In the first part of the thesis we propose channel allocation algorithms for QoS in SC-FDMA based access systems. In multicast systems there is a base station and multicast user groups, where users in a group receive the same information. Traditionally multicast rate is defined as the minimum user rate in a group, which seriously limits the throughput. Using Reed- Solomon the multicast data can be recovered from only a subset of bits/subchannels etc. So with channel dependent scheduling and OFDM it is possible to increase the multicast data of a system with the benefit of Reed-Solomon Coding. In the second part of the thesis we propose subchannel and bit allocation algorithms for multi group multicast systems.