Introduction

Infrared (IR) indoor optical wireless (OW) potentially combines the high bandwidth availability of optical communications with the mobility found in radio frequency (RF) wireless communication systems. So although IR is currently overshadowed by a multitude of home and office RF wireless networking schemes, it has significant potential when bandwidth demand is high. Compared to an RF system, OW offers the advantageous opportunity for high-speed medium- to short-range communications operating within a virtually unlimited and unregulated bandwidth spectrum using lower-cost components. Furthermore, OW systems may be securely deployed with immunity to adjacent communication cell interference because the signal radiation cannot penetrate opaque barriers such as walls. Low transceiver costs, coupled with rapid deployment and compatibility with the existing optical fiber communication systems mean that OW is an attractive alternative when fiber deployment is difficult [1], [2]. Moreover, band-width congestion in the RF domain has led to the installation of optical hotspots in public buildings and application-specific OW hotspots can be integrated into future office designs [3]. Optical wireless communication has attracted considerable attention from the academic community. From its short-distance, low-speed origins [4], OW has become a viable addition to communication systems with promising prospects, having passed the 155 Mbps indoor landmark during the 1990s [5]. In recent years, techniques such as multispot diffusion (MSD) [6], angular diversity [7], and rate adaptive modulation [8] have been adopted as will be discussed later in this chapter.