Performance investigation of IEEE 802.11af systems under realistic channel conditions

As the analog TV broadcasting channels have become less frequently used in the last decade, there has been a great interest in these frequency bands for the deployment of metropolitan, local and personal area networks. Among them, the local area network standard IEEE 802.11af defines PHY and MAC layer implementation of such networks in these unused frequency bands, also named television white space (TVWS). According to the standard, the systems may use contiguous or non-contiguous channels during their operation, depending on the channel availability. In this paper, we investigate in detail the performance of different operation modes of these systems under realistic channel conditions. While the perfect knowledge of channel would result in similar system performances, as the number of in-between-bands occupying the non-contiguous modes is increased the channel estimation performance degrades drastically, which is quantified in this study. In addition, it is shown that determining the true locations of multipaths heavily relies on the selected channel resolution and has a significant effect on the system performance. Numerical examples are given to demonstrate the effects of both the non-contiguous operation modes and the selected channel resolution.