The Difference Between Line Of Sight and Non-Line Of Sight
Line of Sight (LOS): In LOS communication, there is a direct, unobstructed path between the transmitter and receiver. This type of communication is typically more reliable and offers higher data transfer rates because there are minimal obstacles in the signal’s path. LOS is commonly used in technologies like optical communication and certain wireless communications.
Non-Line of Sight (NLOS): NLOS communication involves obstacles or reflections that hinder a direct line of sight between the transmitter and receiver. This can occur in urban environments, indoors, or when there are physical barriers such as buildings or terrain. NLOS communication may require additional technologies or signal processing techniques to overcome obstacles and maintain a reliable connection.
In essence, LOS has a clear, unobstructed path, while NLOS involves communication with obstacles or reflections in the signal path.
Earlier wireless technologies (LMDS, MMDS for example) were unsuccessful in the mass market as they could not deliver services in non-line-of-sight scenarios. This limited the number of subscribers they could reach and, given the high cost of base stations and CPE, those business plans failed. WiMAX functions best in line of sight situations and, unlike those earlier technologies, offers acceptable range and throughput to subscribers who are not line of sight to the base station.
Buildings between the base station and the subscriber diminish the range and throughput, but in an urban environment, the signal will still be strong enough to deliver adequate service. Given WiMAX’s ability to deliver services non-line-of-sight, the WiMAX service provider can reach many customers in high-rise office buildings to achieve a low cost per subscriber because so many subscribers can be reached from one base station.