1 Admission Control for Non-preprovisioned Service Flow in Wireless Metropolitan Area Networks Liping Wang, Fuqiang Liu, Yusheng Ji, and Nararat Ruangchaijatupon Fourth European Conference on Universal Multiservice Networks, 2007 ( ECUMN '07 )

2 Outline Introduction Proposed admission control policy Admission control policy with guard channel scheme and proportional bandwidth-borrowing scheme Simulation Conclusion

3 Introduction Broadband wireless access (BWA) –Provide the last-mile connection –Support mobility Two or three pairs of management connections are built between MS and BS after MS entry the network

4 Five schedule service classes based on QoS Unsolicited grant service (UGS) –CBR and VoIP Real-time polling service (rtPS) –MPEG video Extended real-time polling service (ertPS) –VoIP with silence suppression Non real-time polling service (nrtPS) –FTP Best effort (BE) –Data streams without minimum service level requirements

5 Preprovisioned service flow BS initiates the connection process immediately after MS enter the network The parameters are read from database configured by network provider

6 Non-preprovisioned service flow BS has to decide whether to admit or reject the connection of MS, and how much bandwidth be reserved for it Admission control process According to long term performance and bandwidth usage

7 Admission control Assign a constant bandwidth, the peak rate, or an effective bandwidth to a class of calls Guard channel –Reserves the channels for handover calls Queuing –Give priority to handover calls

8 Two QoS requirements Minimum reserved traffic rate –The minimum rate reserved for the connection –UGS, rtPS, ertPS, and nrtPS Maximum sustained traffic rate –The peak information rate of the service –rtPS, ertPS, nrtPS, and BE

9 Priority of the connections of service classes Handover connections have higher priority than new originated connections The priority of real-time services are higher than non real-time services The priority of queue handover UGS > rtPS and ertPS new originated UGS > rtPS and ertPS >> handover nrtPS > new originated nrtPS> handover BE> new originated BE

10 Bandwidth borrowing scheme Borrow bandwidth from existing connections of non-higher service class –By reducing bandwidth reserved for them –Failing a voice call > worsening video ’ s quality > decreasing transmission rate Maximum sustained traffic rate Minimum reserved traffic rate Borrowed bandwidth 10Kbps 3Kbps

11 Bandwidth-borrowing order UGS have no maximum sustained rate of reserved bandwidth BE have no reserved bandwidth UGS -> rtPS/ertPS and nrtPS rtPS -> rtPS/ertPS and nrtPS nrtPS -> nrtPS

12 Admission control policy with guard channel scheme and proportional bandwidth-borrowing scheme New originated connections request is admitted if (b l - b r )>C·n% Handover connections request is admitted if (b l - b r )>0 C : total bandwidth b l : remaining bandwidth b r : required bandwidth of connection request n% : reserved bandwidth as guard channels

13 An example of bandwidth- borrowing A handover rtPS connection request and the bandwidth has to be borrowed b b =(b r_rt − b l ) Request admits if The amount of bandwidth borrowed from nrtPS connection i b r_rt : minimum required bandwidth of rtPS conncetion b r_nrt : minimum required bandwidth of nrtPS conncetion b rt_i : reserved bandwidth for each rtPS connection i (0 ≤ i ≤ N rt ) b nrt_i : reserved bandwidth for each nrtPS connection i (0 ≤ i ≤ N nrt )

14 An example of bandwidth- borrowing (cont.) Borrows bandwidth from rtPS conncetion if Request admits if The amount of bandwidth borrowed from rtPS connection i

15 Simulation OPNET Modeler 11.5 Each cell is with fixed bandwidth of 10Mbps The arrival of both new originated and handover connections followed poisson distribution with rate λ

16 Bandwidth utilization of the three algorithms

17 Connection-blocking and connection- dropping of the three algorithms

18 Connection-blocking probability and connection-dropping probability of ACP & GC

19 Connection-blocking and connection- dropping of each service class using ACP & GC

20 Connection-blocking and connection- dropping of each service class using ACP&GC&BB

21 Conclusion Proposed an admission control policy for non- preprovisioned service flow Added a guard channel scheme to provide higher priority to handover connection and used a novel proportional bandwidth-borrowing scheme These two scheme greatly reduce both connection-blocking probability and connection- dropping probability of each kind of connection

22 Thank you