Distributed Downlink Radio Resource Management in Multi-cell IEEE 802.16e Systems

In this paper we consider dynamic radio resource management (RRM) in multi-cell OFDMA based IEEE 802.16e network. Special techniques are required to coordinate the mutual interference between cells. In this paper we propose a new distributed radio resource management algorithm for downlink traffic in multi-cell IEEE 802.16e network. In the proposed scheme the complex problem of dynamic radio resource management is split into two sub-problems. The first problem is the RRM at the Radio Network Controller, (RNC) which coordinates a set of base stations (BSs) and decides the set of subcarriers assigned to each BS. The second problem is the radio resource management at the BS which is comprised of scheduling the current users' backlog on the subcarriers allocated to the BS. We assume that each cell is divided into two regions: the first is the collision region which is the outer area of the cell where high inter-cell interference exists, and the second is the inner region of the cell where inter-cell interference can be handled efficiently. For better performance RRM at RNC is applied to users inside the collision region while users outside the collision region are allowed to use all the subcarriers available in the system. We provide simulation results comparing our distributed ARM scheme with different schemes. We examine the effect of the choice of some system design parameters on the performance. The simulation results illustrate the superiority of the proposed scheme for different choice of system design parameters.