Practical aspects of interference management in wireless networks

Delivering broadband to the user end via wireless has been considered a secondary option and exercised only when the wired link solution computes an unsatisfactory investment return. This paradigm is changing, however, with a number of WiFi metropolitan networks promising profitability in niches traditionally operating with cables. It is expected that these new wireless enterprises will face innumerous obstacles of practical nature, as they grow and deploy in large scale. Problems with large scale wireless deployments may range from coexistence and interference amongst different service providers to billing procedures. In such a scenario, the Communications Research Centre (CRC) set out to design, develop, and deploy a wireless broadband system. Besides the challenges of designing a whole system, CRC engineers were faced with important RF management issues and some of which are the subject of this paper, namely: RF management related to TCP/IP packet duplication over the air due to multipath propagation, intrasector communication within a multisectored cell system and the downlink near-far power problem, to name a few. This work highlights critical problems, that we found unique and not reported before, that are most likely to be encountered by emerging networks (WiMax and WiFi) and proposes solutions to overcome them.