Spectrum Occupancy for 802.11a/n/ac Homogeneous and Heterogeneous Networks

Abstract

Given the increasingly overcrowded 2.4 GHz spectrum band, there is a growing interest in utilizing the frequency spectrum in the less congested 5 GHz bands. Notably, Wi-Fi is one of the leading causes of interference in the 5 GHz bands; therefore, examining its spectrum occupancy is important for developing technologies and planning spectrum use in those bands. This paper provides experimental measurements of Wi-Fi spectrum occupancy in the 5 GHz band. Duty cycle (i.e., channel utilization) is used to measure Wi-Fi spectrum occupancy. The results of this paper are important for the study of wireless coexistence of homogeneous and heterogeneous networks in the 5 GHz spectrum. As the duty cycle increases, there is a higher possibility for other wireless devices to hold back from transmission or to increase the number of errors in transmission. The work presented herein provides duty cycle measurements for single pair, as well as two- and three-pair homogeneous and heterogeneous Wi-Fi networks. Duty cycle measurements are presented for 802.11a, n, and ac networks at various throughput levels. Measurements were obtained using a tool developed in the frequency domain. Results show that an 802.11a network achieves lower duty cycle and throughput values than 802.11n and ac. Moreover, 802.11ac achieves a lower duty cycle than 802.11n for a higher throughput. Findings demonstrate that duty cycle may reach up to 98.14% when three 802.11ac pairs share the same frequency channel.