1 Predictive Group Handover Scheme with Sub-Channel Borrowing for IEEE j- enabled Vehicular Networks Broadband Wireless Communication and Multimedia Laboratory, Tongji University Lianhai Shan

2 Outline Features of Group Handover and Problems Statement Proposed Scheme: PGHO-CB Performance Analysis Simulation Scenario and Result Analysis Conclusion and Future Work

3 Mobile RS Application Scenario Relay Station: Enhance the signal strength Extend the coverage

4 Group Handover Scenario Broadband Wireless Access using IEEE802.16j for Mobile Multi-hop WiMAX SINR of a neighbor BS is larger than the current serving BS, (the hysteresis margin, threshold), then the handover of group users will happen.

5 Problems for Group Users Heavy burden for BS Long system delay in the GHO process Handover dropping probability

6 Outline Features of Group Handover Problems Statement Proposed Scheme: PGHO-CB Performance Analysis Simulation Scenario and Result Analysis Conclusion and Future Work

7 GHO Flow Chart

8 Proposed Scheme Predictive Group Handover (PGHO) Location and moving direction information Channel Borrowing (CB) Borrowing Channels from the existing service in the target BS by decreasing the QoS level. PGHO-CB: Predictive Group Handover with sub-channel borrowing

9 Proposed Scheme Mobile direction serving BS ID, average dwelling time, next target BS ID Count On route(ID_1, T100, ID_3)22 On route(ID_1, T60, ID_4)5 On route……… Return route(ID_8, T80, ID_6)20 Return route(ID_8, T120, ID_7)4 Return route…… Movement History Database Large vehicles moving routes is fixed such as light rails, subways.

10 Proposed Scheme Erlang-B formula reversely to estimate the number of sub- channel required Result: : CBP of nrtPS in a BS; : CBP of rtPS in a BS; is the number of sub-channels needed for the coming GHO is available sub-channels in the target BS

11 Proposed Scheme Sub-Channel Borrowing (CB) for PGHO Detailed CB is within my published papers, will appear in LNCS of Apweb09.

12 Outline Features of Group Handover Problems Statement Proposed Scheme Performance Analysis Simulation Scenario and Result Analysis Conclusion and Future Work

13 Single Handover Model 2-D Markov state transition diagram

14 Single Handover New calls blocking probability (CBP) of rtPS and nrtPS handover blocking probability (HBP) of rtPS and nrtPS rtPS nrtPS rtPS nrtPS

15 Proposed Group Handover Markov transition diagram for a Single MS using PGHO scheme Markov transition diagram for a Group MSs using PGHO scheme

16 Proposed Group Handover New calls blocking probability (CBP) of rtPS and nrtPS

17 Proposed Group Handover handover blocking probability (HBP) of rtPS and nrtPS

18 Adaptive HO CAC Delay : represents the handover CAC adaptive factor : represents exponential factor, decided by the different service types : the highest speed : the largest handover CAC delay time : the least handover CAC delay time as

19 HO Dropping under Different Velocity : HBP in the handover CAC process : the time of handover CAC process of each time : practical delay of handover CAC process If, handover QoS will reduce If, handover dropping will happen the longest handover CAC delay that can ensure the connection

20 Outline Features of Group Handover Problems Statement Proposed Scheme Performance Analysis Simulation Scenario and Result Analysis Conclusion and Future Work

21 Simulation Parameter parametersvalue Number of Cells19 Operating Frequency2500MHz DuplexTDD System Channel Bandwidth10MHz BS Height32 meters Mobile Terminal Height1.5 meters BS Antenna Gain15 dBi MS Antenna Gain-1 dBi BS Maximum Power Amplifier Power43 dBm Thermal Noise-174 dBm/Hz Sampling Frequency11.2MHz FFT Size (N FFT )1024 Sub-Carrier Frequency spacing10.94kHz Frame Duration(TTI)5 milliseconds Number of OFDMA Symbols48 Propagation ModelCOST231-Hata

22 Simulation Parameter parametersvalue Number of Channels30 Dwelling time0.5 Call completion rate =0.5 new call arrival rates of rtPS new call arrival rates of nrtPS System traffic load channel number of one rtPS (min-max)2-4 channel number of one nrtPS (min-max)1-3 radius of BS coverage 1.28 km

23 New calls and HO blocking probability

24 Handover dropping probability

25 Average handover delay

26 Outline Features of Group Handover Problems Statement Proposed Scheme Performance Analysis Simulation Scenario and Result Analysis Conclusion and Future Work

27 Conclusion PGHO-CB predict the target BS for mobile RS Target BS prepare the needed resource for HO using the Sub-Channel Borrowing Decrease the HDP significantly of group handover

28 Future Work Two-level Channel Reallocation for Group Handover after Sub-channel Borrowing System Performance of GHO

29 Thanks Q&A