Joint User Association and Power-Bandwidth Allocation in Heterogeneous Cellular Networks

Abstract

Transmission delay minimization can be considered as an ideal goal for any data transmission system. Regarding the radio resources restriction in cellular networks (e.g. transmit power and bandwidth of base stations (BSs)) delay improvement is taken into account as a complex network optimization problem. Here, the decision process of user association to multiple BSs and traffic load balancing is proposed which improves the resource utilization and establishes the throughput required by each network user with the minimum total average transmission delay. The network to be investigated is heterogeneous cellular network. The average delay is formulated and an optimization problem is proposed to minimize the delay subject to power and bandwidth limitation and also the rate stability condition. This problem is originally nonconvex and a combination of difference of convex method and inner approximation is utilized to convert the problem to a convex form. Various types of user distribution are examined in simulation and the results show significant decrease in system delay average compared to well-known user association approaches such as minimum distance and maximum received signal straight criteria.