博士論文摘要
In this dissertation, we present two channel preemption algorithms for cellular networks with overlapping regions; adaptive channel preemption (ACP) algorithm for small-cell embedded large-cellular (SCELC) networks and channel reservation and preemption (CRP) algorithm for sector-based cellular networks (SBCN). An SCELC network consists of a fixed base station (FBS) with large coverage and many embedded base stations (EBS) with relatively small coverage. In an SCELC network, we consider two aspects of dynamically allocating channels. First, by increasing one or more EBS cells within an FBS cell, the proposed ACP can reduce blocking probability of new calls. Second, to reduce dropping probability of handoff calls, the proposed ACP allows a handoff call to preempt an ongoing call, when the latter is located in an EBS cell or in the overlapping area of two adjacent FBS cells. An analytical model to analyze ACP is built and numerical results reveal that embedding one or more EBS cells inside an FBS cell needs to be done carefully, since it may have a tradeoff between the reduction of new-call blocking probability and the increase of handoff-call dropping probability. On the other hand, CRP algorithm is proposed for SBCN to reduce the dropping probabilities of handoff calls. Specifically, when free channels in a sector are not available, a handoff call, instead of being dropped, is allowed to preempt an ongoing call residing in the overlapping region of two adjacent sectors or two neighbor cells. An analytical model to analyze CRP is built and analytical results show that the proposed CRP can significantly reduce the dropping probabilities of inter-sector handoff calls, particularly when traffic between two sectors is not evenly distributed.
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Publication List
Journal Paper:
1. Tsang-Ling Sheu and Chia-Nan Lin, “An Adaptive Channel Preemption Model for Small-Cell Embedded Large-Cellular Networks,” Wireless Communications and Mobile Computing, DOI: 10.1002/wcm.1110, Dec. 2011. (SCI, EI, 2007 Impact Factor: 1.225, Ranking: TELECOMMUNICATIONS Top: 13/66 = 19.7%)
2. Tsang-Ling Sheu, Chia-Nan Lin, and Jenq-Neng Hwang, “A Channel Reservation and Preemption Model using Overlapping Regions in Sector-based Cellular Networks,” Wireless Communications and Mobile Computing, DOI: 10.1002/wcm.2447, Oct. 2013. (SCI, EI, 2007 Impact Factor: 1.225, Ranking: TELECOMMUNICATIONS Top: 13/66 = 19.7%)
Conference Paper:
1. Tsang-Ling Sheu and Chia-Nan Lin, “Adaptive Channel Preemption Model for Small-Cell Embedded Large-Cellular Networks,” IEEE International Conference on Communication Systems (ICCS), Singapore, Page(s): 416-420, Nov. 17-19, 2010.
2. Chia-Nan Lin and Tsang-Ling Sheu, “Preemptive Channel Allocations for Cellular Networks with Multiple Sectors,” International Conference on Networking and Services (ICNS), Venice, Italy, Page(s): 14-19, May 22-27 2011.
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