Ser Wah Oh

Dynamic path switching routing protocol for cognitive radio networks

The majority of this paper is to develop a reliable and high-performance routing protocol for cognitive radio networks (CRN). Due to the presence of the high-priority users (primary users) in the CRN, an existing routing path may easily become unavailable for any link on the path being occupied by primary users (PUs). The most intuitive way to avoid this problem is to select the path in which fewer PU activities are observed at the cost of performance sacrifice. This paper proposes a novel CRN routing protocol which aims to maintain the performance by utilizing the high-quality link as much as possible and to alleviate the route repair cost due to the occurrence of PUs. The experimental results show that in most situations, the proposed protocol outperforms other routing protocols including one traditional and two CR routing protocols in terms of packet round-trip delay, total system throughput and packet loss rate. The results also show that the proposed protocol is very resistant to the variation of PU activities.

Pricing Model for TV White Spaces Channels With Different Priorities

A new type of TV white space (TVWS) channel called the high priority channel (HPC) has been proposed by the regulator of Singapore. The HPCs are TVWS channels that will always be available to unlicensed white space devices (WSDs) although a white space database (WSDB) provider may impose fees to WSDs for using HPCs. The HPC is of interest to WSDB providers since it creates a new business opportunity for them. In this letter, we investigate the optimal fee for using HPCs such that the WSDB provider achieves the maximum revenue. The solution of the optimal fee is provided in this letter. From this study, it is observed that WSDB provider should not always increase the fee when the total number of WSDs increases as our results show that sometimes lowering the fee to attract more WSDs to use HPCs actually increases the revenue.