Description
IEEE 802.11af proposes the use of unused TV channels, which are collectively named as TV white spaces. The spectrum opportunity for TV white spaces consists of fragments of different number of TV channels that already allocated to broadcasters but not being use at all times. Based on the availability of contiguous channels or non-contiguous channels within a set of N consecutive channels, 802.11af allows bonding of multiple TV channels to offer a larger bandwidth. This thesis investigates OFDM Fixed Carrier Spacing (FCS) and Fixed Carrier Numbers (FCN) approaches from a channel bonding view in IEEE 802.11af networks. We present a comparative analysis of FCS and FCN approaches in OFDM. An analysis of throughput improvements through channel bonding and compatibility with existing 802.11a/b/g/n standards is provided. We also endeavor channel bonding and channel loading concept in TVWS. We mainly focus on channel loading and bonding concept to increase the physical data rate. Adaptive modulations in 20 MHz channel and 6 MHz fragmented TV channels will be discussed. Each 6 MHz TV channel with 5 MHz bandwidth availability can adaptively choose modulation scheme as per SNR availability using the channel-loading concept. We developed a new signal field design to support channel loading/bonding in 802.11af. We present an analysis of TV spectrum availability in rural, urban and suburban areas in Southern California region.
