On the Blockage Effect in Pinching-Antenna Systems (PASS)

Jinhua Wang, Jun Wang, Tianwei Hou, Xin Sun, Arumugam Nallanathan

Pinching-antenna systems (PASS) offer considerable potential for wireless communications due to their unique ability to dynamically reconfigure radiation positions along a waveguide. However, the performance of PASS remains a critical challenge in the presence of random line-of-sight (LoS) blockage, leading to significant attenuation and even communication outages. In this paper, the performance of PASS in the presence of LoS blockage is investigated from the perspective of stochastic geometry. Obstacles are modeled through a homogeneous Poisson point process (PPP), where the geometric dimensions, numbers, and positions are treated as random variables. To conduct a concrete characterization of LoS blockage, the random-height-and-random-radius (RHRR) blockage model and the deterministic-height-and-deterministic-radius (DHDR) blockage model are proposed. In particular, closed-form analytical and asymptotic expressions for the outage probability are obtained, along with analytical and approximate expressions for the ergodic rate. Our simulation results reveal that denser obstacle environments or statistically larger obstacles substantially increase the probability of LoS blockage and degrade the system performance. Moreover, owing to its ability to dynamically reposition PAs, PASS can consistently outperform conventional antenna systems in the presence of LoS blockage.