Assessment of a Platform for Non-Contiguous Aggregation of IEEE 802.11 Waveforms in TV White Space

TV White Spaces (TVWS) and associated spectrum sharing mechanisms represent key means of realizing necessary prime-frequency spectrum for future wireless communication systems. We have been leading a major trial of TVWS technology within the Ofcom TV White Spaces Pilot. As one aspect of the work of our trial, we have investigated solutions for aggregation in TVWS and as part of that the performance of InterDigital White Space Devices (WSDs), capable of aggregating a IEEE 802.11 enabled technology for operation in up to 4 TVWS channels, non-contiguously as well as contiguously. This paper reports on some of our assessment of aggregation in TVWS, as well as our assessment of the InterDigital WSDs. It reports on the white space channel availabilities that can be achieved through aggregation, based on a real implementation of a WSD exhaustively testing a large area of England with a high resolution. The considerable benefit that is achieved through allowing non-contiguous aggregation as compared with contiguous-only aggregation is shown. Further, this paper assesses the TCP and UDP throughput performances of the InterDigital WSDs against the number of channels aggregated and received signal powers, in highly controlled scenarios. Statistics on performance of the WSDs for the studied large area of England are derived based on this. These results are compared with theoretical similar WSDs with one major difference that they can only achieve contiguous channel aggregation. Results show almost a doubling of capacity through non-contiguous aggregation with the InterDigital WSDs; this performance benefit would be increased significantly if more than 4 channels were supported for aggregation.