Non-Line-of-Sight (NLoS) and Near-Line-of-Sight (nLoS) are terms used to describe the types of radio frequency (RF) path propagation in wireless networking and communication systems. These terms are significant in understanding the capability of a wireless system to transmit and receive signals especially in challenging environments.
Here’s a breakdown of what these terms imply:
- Non-Line-of-Sight (NLoS):
- In Non-Line-of-Sight scenarios, the signal path between the transmitter and receiver is obstructed by obstacles like buildings, trees, or hills. Despite these obstructions, certain wireless technologies are capable of delivering signals by reflecting off or diffusing around obstacles.
- Technologies like TV White Space (TVWS), and certain low-frequency RF technologies can handle NLoS conditions due to their long-wavelength signal propagation characteristics.
- NLoS technology is especially beneficial in urban areas with many buildings and other obstructions, or in hilly or forested rural areas where a clear line of sight is difficult to achieve.
- Near-Line-of-Sight (nLoS):
- Near-Line-of-Sight scenarios fall between clear Line-of-Sight (LoS) and Non-Line-of-Sight. In nLoS conditions, there may be a partial obstruction in the signal path, like a single tree or a small hill, but there’s still a decent amount of visibility between the transmitter and receiver.
- Wireless signals may still travel effectively between the transmitter and receiver with minimal degradation, depending on the level of obstruction and the wireless technology being used.
- Certain wireless technologies and antenna solutions can be engineered to deal with nLoS conditions by achieving a higher gain or employing MIMO (Multiple Input Multiple Output) technology to improve signal reception and integrity.
- Importance in Network Design:
- Understanding the LoS, nLoS, and NLoS conditions of a deployment area is crucial for effective network design. It informs the choice of wireless technology, antenna type, and placement, which in turn affects the performance, reliability, and coverage of the wireless network.
Both NLoS and nLoS capabilities are highly valued in wireless technologies, especially in regions with challenging terrains or dense urban structures. They enable the provision of wireless connectivity in areas where it would be otherwise difficult or impossible with traditional LoS wireless solutions.