Katzis, Konstantinos

Cognitive radio-based TV White Space (TVWS) is a promising idea which seeks to increase spectrum utilization by opportunistically accessing spectrum initially licensed to TV transmitters or incumbents. Orthogonal frequency multiple access (OFDM) is thought to be a promising technology for TVWS systems. In this paper, we consider an OFDM based cognitive High-Altitude Platform (HAP) exploiting the TVWS spectrum. We employ dynamic resource allocation for providing wireless access from a HAP at an altitude of 20km, while utilizing the TVWS spectrum. This paper focuses on the resource allocation algorithms, which are designed to increase the system transmission rate of secondary users while keeping the disturbance applied to the incumbent band below a threshold level and the overall power within a range using the Artificial Immune System Algorithm. As per the simulation demonstrated so far, the proposed algorithm outperforms the water-filling algorithm, implying that the system transmission rate is greatly optimized. Moreover, the proposed resource allocation algorithm allocates resources to users in a fair manner, without favoring any particular user, and has good convergence performance.

The beginning of TV white space (TVWS) for cognitive system is amongst the perceptible move towards solving the spectrum scarcity as well as rural connectivity problems. For the reason that this section of the spectrum band has higher bandwidth, good transmission characteristics and wide coverage. In this paper, we proposed a realistic implementation of the TVWS assignment simulation method focused on geo-location that solves the issue of spectrum under-utilization. The model is aided by the Calculation Engine of CSIR which is used in the radio frequency band of interest in Ethiopia to Intelligently quantify white spaces. More broadly, we aimed at the necessary input parameters, like radio propagation models suitable for the Ethiopian terrain environment, and calculation procedures to determine underutilized TVWSs. The models used by the Engine will approximate the contour coverage span of the incumbent TV station, separation distances for neighboring and co-channel locations, co-channel lists, as well as adjacent channels. In addition, using the planned implementation for the Ethiopia usage case; substantial amounts (87.9–98.23%) of geographically unoccupied broadcast TV channels are identified, such channels can be used for secondary provisioning of inexpensive broadband wireless networks.