tailieunhanh - Developments in indoor optical fiber wireless networks

This paper presents a detailed review of recent developments in modulation schemes, transmitter and receiver domains which will enable the realization of future high performance and cost-effective indoor optical wireless systems. | ISSN:2249-5789 Beena R Ballal et al, International Journal of Computer Science & Communication Networks,Vol 1(2),100-104 Developments in Indoor Optical Fiber Wireless Networks Nema, Beena R Ballal Professor (EXTC,VESIT,Mumbai),Student(, EXTC,VESIT,Mumbai) seeshikhanema@, beenarballal@ Abstract Optical wireless is an innovative technology combining the mobility of radio frequency (RF) wireless communications with the high bandwidth availability of optical communications. Next generation of wireless communication systems (4G) will be based on several technologies including optical wireless (OW).This paper presents a detailed review of recent developments in modulation schemes, transmitter and receiver domains which will enable the realization of future high performance and cost-effective indoor optical wireless systems. Indoor optical wireless systems offer lower path loss and less multipath dispersion, at a lower transmission power compared to ‘conventional’ wide-angle diffuse systems, while providing a high level of user mobility compared to line-of-sight transmission. These developments in turn will prove very beneficial for optical wireless systems to fulfil their promise by adopting a philosophy inspired by the radio domain to accommodate operation within a hostile channel 2. Design Challenges The major design challenge for such communication systems is to achieve a sufficiently high signal-to-noise ratio (SNR) at useful data rates. Since the SNR for an optical wireless link is proportional to the square of the average received optical signal power, transmission at higher power levels compared to the electrical channel is required. The system should be designed for minimum path loss since power is limited by eye safety considerations [1]. A receiver having a large lightcollection area should be employed. The dominant source of noise in indoor optical wireless systems is ambient light, which is typically a combination .