Chapter 2 - Harnessing Network Coding in Wireless Systems

Abstract

Wireless networks suffer from a variety of unique problems including low throughput, dead spots, and interference. However, their characteristics, such as the broadcast nature of the medium, spatial diversity, and significant data redundancy provide opportunities for new design principles to address these problems. This chapter describes advances in employing network coding to improve the throughput and reliability of wireless networks. Wireless networks have been designed using the wired network as the blueprint. The design abstracts the wireless channel as a point-to-point link and grafts wired network protocols onto the wireless environment. The wireless medium is fundamentally different. While wired networks have reliable and predictable links, wireless links have high bit error rate, and their characteristics could vary over short time scales. Transmissions in a wired network do not interfere with each other, whereas interference is a common case for the wireless medium. Network coding enables more efficient, scalable, and reliable wireless networks. These opportunities come with a need for rethinking the media access control (MAC), routing, and transport protocols. Recent years have seen significant successes in integrating network coding into wireless systems and the emergence of practical implementations with significant throughput and reliability gains.