Stochastic modeling of the static and dynamic multichannel access methods enabling 40/80/160 MHz channel bonding in the VHT WLANs

The use of 40, 80, and 160 MHz wideband channels is enabled in the current IEEE 802.11ac standard through the channel bonding technique used at the physical layer. To obtain such wide channels, two multichannel access methods have been defined at the MAC (Medium Access Control) layer, namely: static and dynamic, which allow bonding multiple 20 MHz narrow channels. The dynamic method is flexible, it is content to take the available part of the requested bandwidth. However, the static method is rigid, it is based on all-or-nothing principle. In this letter, we propose for each of these methods a discrete time Markov chain that aims to: (i) identify functional operations of the static and dynamic methods (ii) compute and compare the expected bandwidth of both methods. The obtained numerical results show that the bandwidth expectancy of the dynamic method is the best in most cases. At worst case it gets nearly the same bandwidth expectancy as the static method.