Optimal resource allocation in wireless systems under quality of service constraint

Abstract

Optimal exploitation of available resources is one of the most important aspects of modern communication systems. Resource allocation algorithms are used to allocate bits and powers to the subcarriers of a multi-carrier communication system from the knowledge of the channel. The OFDM (Orthogonal Frequency Division Multiplexing) is the combination of OFDM and precoding. The idea is to group subcarriers into subsets using precoding matrices. Each subset uses the energy of its sub-carriers for transmitting a total number of bits greater than the sum of bits that can be transmitted on each subcarrier individually. The role of resource allocation in multi-carrier systems is to optimize either the throughput or robustness of the system. Under the PSD (Power Spectral Density) constraint and for a given error rate, the resource allocation typically gives either the maximum bit rate for a given system margin or the maximum system margin for a target bit rate.