Optimal scheduling and subchannel allocation in wireless communications systems

Abstract

Next generation mobile communication systems will allow many different services with various demands on data rate and delay. For those systems, the fixed radio resource management (RRM) applied to voice service or low rate data service systems may not be applicable to ensure efficient utilization of the radio spectrum. Dynamic resource allocation such as scheduling and dynamic channel allocation are necessary in order to cope with large variations in data rate and to achieve high spectral efficiency. This thesis studies the scheduling policy over a shared channel and subchannel allocation in multi-carrier systems. First, we consider a packet scheduling problem over a shared channel in wireless networks. We present a modified proportional fiar scheduling and investigate the trade-off between system throughput and proportional fairness by asymptotic analysis. Also, subject to the constraint to guarantee individual quality of service (QoS) requirements, a parameter optimization scheme to increase the system throughput is proposed. Secondly, a proportional fair scheduling which has beer proposed for high data rate (HDR) system which is a single carrier transmission system also known as 1xEv/DO is extended to a multi-carrier transmission systems. HDR can be considered as a special case when the number of carriers is one. The proposed proportional fair scheduling for multicarrier systems only requires information on the user rates selected by a scheduler, not those of all users, thereby reducing the computational complexity. Thirdly, we consider a subcarrier allocation problem for cellular orthogonal frequency division multiple access (OFDMA) systems with adaptive modulation and coding (AMC). A linear programming (LP) formulation subject to the constraints of quality-of-service (QoS) and limited bandwidth was made to provide the allocation scheme for the optimal system throughput. We propose an optimal subcarrier allocation scheme which allow cell coordination ...