Optimal operation scheme for heterogeneous networks

Abstract

One of key issues in wireless communications is to maximize system performance by efficiently managing limited radio resources. A lot of radio resource management researches to solve the issue have been studied. Recently, new paradigms in wireless communications such as cooperative communication, cognitive radio and heterogeneous networks have been introduced to maximize the efficiency of radio resource uses by allowing system-wise radio resource uses. Efficient resource management schemes suitable for future wireless networks based on the new paradigms have been required. In this thesis, raido resource management schemes for heterogeneous networks based on new paradigms are addressed. Firstly, resource sharing in cooperative networks considering transmission of own data by a relay node have been studied. Most of these researches took individual view based approach under which each node is considered as independent unit who makes an effort to maximize own throughput. In this paper, we investigate time and power sharing in the cooperative network under system view. The joint optimization problem is formulated to maximize weighted sum rate subject to resource constraints. Then, optimal time and power sharing can be easily obtained by proving it as convex problem. Numerical results show that proposed resource sharing improves system performance as compared to existing ones. It can be expected that proposed resource sharing provides a guideline for applications in approaches under individual view. Secondly, efficient QoS aware vertical handoff decision algorithm in heterogeneous wireless networks is investigated. In future wireless communication networks, seamless handoff either by vertical or horizontal is an important issue in radio resource management. For a vertical handoff (VHO), each candidate network is evaluated as a function of multiple attributes such as available bandwidth, delay, data rate, and cost, etc. However, the variations of these parameters and...