Radio Resource Management in Multi-Tier Cellular Wireless Networks

CHAPTER 10

RESOURCE ALLOCATION IN MULTI-TIER NETWORKS WITH COGNITIVE SMALL CELLS

10.1 INTRODUCTION

For small cells to succeed, cognition is expected to be a necessary feature that should be implemented in all types of small cells for their efficient operation with limited centralized control. This cognition will enable the small cells to have the SON capabilities (e.g., self-configuration, self-optimization, and self-healing) which will result in low capital expenditure (CAPEX) and operation expenditure (OPEX) for the network operators. For cognitive small cells, the corresponding BSs, that is, SBSs, will be capable of monitoring the surrounding environment, locating major interference sources and avoiding them by opportunistically accessing the orthogonal channels. The concepts of dynamic spectrum access used in cognitive radio can be applied to multi-tier networks with small cells to tackle some of the major challenges of small cell deployment which include the following: limited centralized control, unplanned and massive deployment, limited transmission powers of small cells and huge transmission power gap between macrocells and small cells, coexistence and efficient operation, and requirement for self-organizing capability. Cognitive SBSs should be able to distributively monitor the spectrum and avoid major interference sources by opportunistically accessing the radio channels so that the interference from nearby MBSs and closed access SBSs is avoided. The closed access SBSs ...