A comparison of MAC aggregation Vs. PHY bonding for WLANs in TV White Spaces

The availability of Television White Spaces (TVWS) has recently attracted considerable attention in industry and academia. Given the relatively small amount of bandwidth allocated to each TVWS channel (6, 7 or 8 MHz depending on geography), channel aggregation/bonding, which enables simultaneous usage of multiple TVWS channels, is an efficient approach to increasing the data rate. In this paper we compare channel aggregation at the MAC layer with channel bonding at the PHY layer. Three approaches are investigated: MAC layer aggregation, PHY layer bonding and a new proposal called enhanced PHY (ePHY) layer bonding. We present simulation results that show that when the SINR difference between aggregated/bonded channels is large that (i) the PHY performance of ePHY bonding is superior to PHY bonding both in terms of available data rates and PER performance and (ii) for both slow and fast link adaptation methodologies, ePHY bonding and MAC aggregation deliver higher throughputs than straightforward PHY bonding.