Fairness Evaluation in Cooperative Hybrid Cellular Systems

Many method has been applied previously to improve the fairness of a wireless communication system. In this paper, we propose using hybrid schemes, where more than one transmission scheme are used in one system, to achieve this objective. These schemes consist of cooperative transmission schemes, maximal ratio transmission and interference alignment, and non-cooperative schemes, orthogonal and non-orthogonal schemes used alongside and in combinations in the same system to improve the fairness. We provide different weight calculation methods to vary the output of the fairness problem. We show the solution of the radio resource allocation problem for the transmission schemes used. Finally, simulation results is provided to show fairness achieved, in terms of Jain's fairness index, by applying the hybrid schemes proposed and the different weight calculation methods at different inter-site distances

Coordinated and Distributed MIMO - Guest Editorial

The impetus for this feature topic was spurred by the technical trend in wireless communications: the need for high bit rates (~1 Gb/s) in future wireless systems. However, due to the limited transmit power, the transmission distance cannot be long if the desired transmission rate is very high. In order to have a reasonable coverage area in each cell, antennas centrally attached to the base station in conventional mobile systems should be distributed through the entire cell via wires (or fibers) so that the wireless transmission distance between mobile units and base stations can be shortened. Moreover, reception of one signal at different locations provides spatial diversity against fading. Such network architecture is called a distributed antenna system (DAS). In order to reduce the transmission distance and provide diversity gain, the distributed multiple-input multiple-output (MIMO) concept is introduced to achieve broadband wireless transmission. In addition, coordination from multiple adjacent cells is needed to efficiently use the distributed MIMO. Therefore, coordinated and distributed MIMO becomes crucial. The key to implement coordinated and distributed MIMO is to have the mobiles communicate simultaneously with several remote antennas with perfect coordination between these antennas