Abstract: The efficient use of the bandwidth allocated for a cellular wireless network is crucial for the satisfactory performance of the system. In order to increase the channel utilization, the channels are allocated to different cells in a dynamic way. The dynamic channel schemes can be categorized in to centralized and distributed. However, the centralized schemes are neither reliable nor scalable. The issue of fault tolerance is significant in cellular wireless networks because of mobility, poor quality of wireless links and other constraints. Moreover, most of the existing fault tolerant channel allocation algorithms have been designed in such a way that these can be used with hexagonal cells and for the reuse distance of one cell only. Therefore, in this paper, a new quorum system named as neighbor quorum system specifically useful in channel allocation in cellular wireless systems has been proposed. A fault tolerant distributed dynamic channel allocation algorithm using the newly propose

• Publication Date: 09-Jul-2012
• DOI: 10.15224/978-981-07-2950-9-9459
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Abstract: A new frequency agile BST varactor loaded stacked circular microstrip antenna is presented. The antenna is analysed using extended cavity model. One of two bands of antenna is tunable with the help of BST varactor. The upper band is useful for WiMAX and lower band for other wireless communication systems. Various antenna parameters like return loss, resonant frequency, frequency agility etc. have been investigated. The simulated results agree well with the numerical data. A frequency agility of 60.64% is achieved, which is better than simple Varactor diode loaded antenna. Lowest resonant frequency of 0.866GHz is obtainable that shows a significant physical area reduction.

• Publication Date: 09-Jul-2012
• DOI: 10.15224/978-981-07-2950-9-9465
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