Received Signal Strength Characterization in Mixed LOS and NLOS Environments

The received signal strength (RSS) measurement is widely adopted in wireless positioning due to its simplicity and accessibility. This article utilizes the Boolean line model (BLM) to characterize the RSS distribution considering both line-of-sight (LOS) and non-LOS (NLOS) conditions, where the reflectors are modeled as line segments with random lengths and inclination angles. We begin by calculating the probability of establishing a specular reflection link for a single reflector with a given transmitter-receiver pair. By leveraging this probability, we compute the distribution of RSS for a single NLOS link. By convolving the RSS distributions from the LOS and multiple NLOS paths, the RSS distribution in mixed LOS and NLOS conditions is derived. Theoretical developments are validated by comparing simulations and the experimental data collected from real-world scenarios.