An Incremental Frequency Reuse Scheme for an OFDMA Cellular System and Its Performance

We propose an incremental frequency reuse (IFR) scheme that reuses effectively the radio spectrum through systematic segment allocation over a cluster of adjoining cells. It divides the entire frequency spectrum into several spectrum segments. Based on the above segmentation, a set of cell- specific segment allocation sequences is designed for universal frequency reuse. Here, each sequence defines its own base segment and allocation order. The designed sequences are then assigned to respective cells over the cell cluster. In this scheme, the base segments over the cell cluster are mutually non-overlapped and collectively exhausted, and the added segments are interfered with from surrounding cells, but only in an incremental and coordinated manner. Hence, the proposed scheme can provide better reuse efficiency over the conventional ones such as the classical universal frequency reuse scheme and the soft frequency reuse (SFR) scheme. In addition, the simple and flexible IFR scheme can be easily configured as most existing reuse schemes only by redefining the set of segment allocation sequences. A system-level simulator for an orthogonal frequency division multiple access (OFDMA) cellular system covering surrounding cells up to 3^rd-tier has been implemented. Simulation results show that the IFR scheme provides quite better reuse efficiency as compared to the classical universal reuse scheme and the SFR scheme, especially at the cell-edge region.

I. INTRODUCTION

Over last two decades, there has been an upsurge of demands for mobile and wireless communications from several points of view such as new services and the number of subscribers [1] [2]. In addition, next-generation mobile communication systems should be able to meet high-quality service requirements such as high-quality video and high-speed Internet over wireless networks at the lowest possible price. In particular, tremendous interests in multimedia services are fueling the need for very high data rates in future wireless networks [1]. However, a radio spectrum might be lacking for supporting these demanding services unless an epoch-making improvement in spectrum utilization has been done [1] [2].