博士論文摘要
In this dissertation, we present mathematical analyses for a cellular CDMA communication system by investigating two important performance factors, the spreading code reservation periods and the cell coverage in soft handoff. First, an innovative code assignment scheme is presented by fully utilizing the characteristics of voice and data traffic. In other words, a voice terminal has higher priority to reserve a spreading code to transmit packets in multiple talk spurts, while a data terminal can only transmit packets by either employing the unassigned codes or borrowing the codes from the voice terminals during their silent periods. The code assignment scheme is then extended to analyze a priority-based CDMA system where the code reservation periods can be varied. Two performance measures, the average dropping probability for delay-sensitive traffic and the average packet delay for delay-insensitive traffic, are derived from the analytic models based on the equilibrium point analysis (EPA). Finally, for the cellular CDMA system, we study the influences of enlarging or shrinking the soft handoff coverage on the new-call blocking and the handoff-call dropping probabilities. From the mathematical analyses, we reveal that enlarging the outer cell while fixing the inner cell may significantly increase both blocking and dropping probabilities. On the other hand, if we enlarge the inner cell and fix the outer cell, the two probabilities can be reduced slightly. The impact of activating a call admission control on the proposed cellular CDMA system is also discussed.
Keywords ： CDMA ,
Code Assignment
, Integrated traffic , Priority , Soft handoff , Cell coverage , Blocking , Dropping , Markov model , and Wireless communications.
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Publication List
Journal Papers:
1. Tsang-Ling Sheu and Jaw-Huei Hou, "An Integrated CDMA Code Assignment Model for Voice and Data Traffic in Wireless Communications," IEEE Transactions on Wireless Communications , Vol. 4, No. 2, pp. 528-537, Mar. 2005.
2. Tsang-Ling Sheu and Jaw-Huei Hou, "On the Influences of Enlarging and Shrinking the Soft Handoff Coverage for a Cellular CDMA System," Journal of Information Science and Engineering (JISE), accepted to appear.
3. Tsang-Ling Sheu and Jaw-Huei Hou, "An Analytical Model of Cell Coverage for Soft Handoffs in Cellular CDMA Systems," GESTS Int'l Transactions on Computer Science and Engineering , Vol. 18, No. 1, pp. 209-223, Oct. 2005.
4. Tsang-Ling Sheu and Jaw-Huei Hou, "A Priority-based CDMA System with Variable Code Reservation Periods for Multiclass Traffic," IEE Proc. Commun. , accepted to appear.
Conference Papers:
1. Tsang-Ling Sheu and Jaw-Huei Hou, "A Code Assignment Scheme for CDMA Wireless Networks with Integrated Voice and Data Traffic," IEEE/IEE Int'l Conference on Telecommunications (ICT), Tahiti , Feb. 2003.
2. Tsang-Ling Sheu and Jaw-Huei Hou, "Coverage Area Analysis of Soft Handoff on Cellular CDMA Systems," 10th IFIP Int'l Conf. on Personal Wireless Communications (PWC), Colmar , France , Aug. 2005.
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