Performance Analysis of IEEE 802.11ay Sectors Sweep Management

In IEEE 802.11ad and 802.11ay standards, proposed for millimeter-wave communications, a beacon interval structure is divided into two distinct periods, i.e., the estimation and data periods. During the estimation period, the best sectors and beamforming coefficients match between the access point (AP) and a transmitting station are found. Stations make themselves known by mandatorily accessing one of the NS >0 consecutive slots forming the estimation period, with probability 1/NS. Additionally, a station can also perform multiple retries in the period when the previous attempt did not succeed. However, when a station successfully performs an estimation, i.e., when it accesses a slot without colliding with other competing stations, it halts its activity until the data period. Consequently, the number of stations competing during the estimation period can be reduced over the slots. To address the intricate behavior during the estimation period, we propose a novel discrete-time Markov chain model to compute the expected number of successful estimations per estimation period duration. To provide a comprehensive assessment of the standards' estimation period, we validate the proposed model and compare the performance of the standard with other state-of-the-art medium access control (MAC) protocols and models. The comparative analysis is focused on the influence of the number of competing stations and the number of slots of the estimation period to identify scenarios where IEEE 802.11ad and 802.11ay can achieve higher goodput values that increase the performance of the estimation period.