A Dynamic Channel Allocating Method Adapted to Users’ Preferences in Circuit Switching of W-CDMA

1. A Dynamic Channel Allocating Method Adapted to Users’ Preferences in Circuit Switching of W-CDMA Takayuki KatayamaYoshimi Teshigawara Graduate School of Engineering Soka University, Tokyo Japan {tkatayam,teshiga}@soka.ac.jp

2. Introduction • Recently a number of browser phones which can transmit data by using cellular phone has been increasing rapidly. (million) Over the 60 millions December in 2002 MCPC*prediction In 2004, over 84 million people will subscribe to cellular phone IP cellular phone subscriber （Telecommunications Carriers Association） *Mobile Computing Promotion Consortium

3. Proposed System • Dynamic channel allocating method in consideration of users requests • Extract user preference parameters such as bandwidth, cost, connectivity and sentthem to the base station. • Allocating channels according to users’ requests (satisfactory parameters) by using AHP Enable to provide data communications that satisfies users’ preference requests

4. 1 2 3 4 5 6 7 8 9 Procedure of Channel Allocation UserNo UserLevel ③ User DB ② ① ⑥ Policy Server ④ ⑤ MT BS Bandwidth DB

5. Specifying User Preferences • Specifying operation • Use Java application implemented in cellular phone • Input of importance levels on users’ preferences • Select a level from “most important”, “more important”, “important”, “less important”, “least important” (Importancelevels are easily understood) Input data will be sent to the management server at the BS and be evaluated as significant values by using AHP. Input image

6. No No Channel AllocatingAlgorithm Communication request Remaining channel is enough calculate AHP Yes Allocate channels which user request Calculate AHP Start communication The calling loss are higher than a regular time The connection weights are promoted a higher position Yes No Check the service and the user which currently perform communication Refer to each level of importance which the user perform communication Calculate the users’ quality value using QDm method Yes The connection weight is above “A”point Allocate channel which user request. Start communication Move to calling loss state

7. Use QDm (Quality Deployment for Market pricing) method which applies “AHP” and “value engineering” Method to Determine User Quality Valuation of satisfactory level regarding bandwidth and cost, connectivity Evaluated by AHP User quality is determined

8. 5 4 3 Quality value 2 1 High satisfaction 0 Acquired Channels It falls rapidly It falls gently “proper figure“ Valuation of Satisfactory Level Regarding Bandwidth, Cost and Connectivity Fig. 2 Satisfactory level of “Bandwidth” 5 4 3 Quality value 2 1 Fig. 1 Figure using “proper figure” 0 cost Fig 3. Satisfactory level of “Cost”

9. Simulation 1024kbps MT BS The range of bandwidth available is 32kbps～128kbps ATM Network Table 1. Importance level of user preference

10. Simulation Results(1) ※λ= calling rate (per sec) Fig. 4 Average acquired bandwidth of each level (λ=4.05) Calling loss rate (%) Calling loss rate (%) calling interval（call/sec） Fig. 1 Comparison of each level with calling loss rate Fig. 3 Relationship between cost and average calling loss rate Acquiring bandwidth (kbps) Acquiring bandwidth (kbps) Request channels (kbps) calling interval（call/sec） Fig. 2 Comparison of each level with average acquired bandwidth

11. Simulation Results(2) Fig. 5Relationship between user satisfaction levels and calling interval user satisfactory levels(%） user satisfactory levels(%） calling interval（call/sec） calling interval（call/sec） Fig. 6 Comparison of each importance parameter with user satisfaction level ※λ= calling rate

12. Conclusion We realize that the proposed system is effective for users who want to acquire enough “bandwidth”, to establish “connection” even under heavy traffic, and to make reasonable communications to guarantee items which users request preferentially . Future works • Guarantee of End-to-End QoS • Comparison in the case of packet switching • method applying proposed system