Non-line-of-sight (NLOS)

1. In wireless terminology, it means that there are obstacles or obstructions between the transmitting and receiving antennas. This can include buildings, hills, or other structures that block the direct path between the antennas. NLOS communications can be more difficult to establish and maintain, as the signal can be weakened or distorted by the obstacles in the path. In general, LOS systems are considered more reliable and provide higher data rates than NLOS systems. However, NLOS systems are often used in urban environments where buildings can obstruct the LOS path, and they can be useful for indoor wireless communications or for communication links that require lower data rates. Many wireless communication systems, such as cellular networks, use a combination of LOS and NLOS communication paths to provide reliable service in a variety of environments.