This paper presents a performance analysis of the Non-Primary Channel Access
(NPCA) mechanism, a new feature introduced in IEEE 802.11bn to enhance spectrum
utilization in Wi-Fi networks. NPCA enables devices to contend for and transmit
on the secondary channel when the primary channel is occupied by transmissions
from an Overlapping Basic Service Set (OBSS). We develop a Continuous-Time
Markov Chain (CTMC) model that captures the interactions among OBSSs in dense
WLAN environments when NPCA is enabled, incorporating new NPCA-specific states
and transitions. In addition to the analytical insights offered by the model,
we conduct numerical evaluations and simulations to quantify NPCA’s impact on
throughput and channel access delay across various scenarios. Our results show
that NPCA can significantly improve throughput and reduce access delays in
favorable conditions for BSSs that support the mechanism. Moreover, NPCA helps
mitigate the OBSS performance anomaly, where low-rate OBSS transmissions
degrade network performance for all nearby devices. However, we also observe
trade-offs: NPCA may increase contention on secondary channels, potentially
reducing transmission opportunities for BSSs operating there.

Este artículo explora los viajes en el tiempo y sus implicaciones.

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