1. Utility-Based Resource Allocation for Layer- Encoded IPTV Multicast in IEEE 802.16 (WiMAX) Wireless Networks Wen-Hsing Kuo ( 郭文興 ),Te-huang Liu ( 劉得煌 ), Wan-jiun Liao ( 廖婉君 ) IEEE International Conference on Communications 2007

2. Outline Introduction Utility-Based Layer-Encoded Multicast (ULEM) Scheme Simulation Results Conclusion & Future works

3. Introduction IEEE 802.16(WiMAX) is a promising last mile technology for broadband wireless access Compared to IEEE 802.11 (WiFi) Higher bandwidth Broader Coverage range IEEE 802.16(WiMAX) is an Excellent platform to provide IPTV streaming service to residential users

4. Introduction To provide high-quality IPTV multicast service, radio allocation is the key factor Contributions of this paper Utility-Based Resource allocation scheme for IPTV multicast Layer-encoded Based on dynamic channel condition System channel utilization improvement Supports unicast stream

5. Introduction Each Video Stream (Program) is encoded into several sub- streams (i.e. Layers) Video Stream (Program) Encoded Video Sub-Stream 01 (Layer 01) Video Sub-Stream 02 (Layer 02) Video Sub-Stream N (Layer N) ….…. Base Layer Enhancement Layer http://0rz.tw/8e3Yv Reference :

6. Introduction For each layer-encoded stream multicast through the network, different receivers may receive different numbers of layers according to channel quality The more layers a subscriber has received, the better the video quality.

7. Introduction Very few existing research is related to IEEE 802.16’s multicast MAC scheme All subscribers have the same channel condition [ 3]Wing-Fai Poon, Kwok-Tung Lo and Jian Feng,"Performance study for streaming layered encoded videos in broadcast environment," Proc. ICITA 2005. All subscribers receive the same number of layers [4] J. Kim, J. Cho, and H. Shin, “Resource allocation forscalable video multicast in wireless cellular networks,” in Proc.WiMob 2005.

8. Utility-Based Layer-Encoded Multicast Scheme Given a user group, BS picks up group members one by one into services in decreasing order of their channel conditions and use the most robust burst profile among all selected users to transmit data. SS 1 SS 2 SS 3 SS 4 SS 5 SS 6 SS 7 SS 8 SS 9 SS 10 Suppose SS 1, SS 2, SS 6, SS 4 have the same Program m requests Example: Transmission Rate SS 1 = 0.5 bytes/sec SS 2 = 0.8 bytes/sec SS 6 = 1 bytes/sec SS 4 = 0.7 bytes/sec Add Order SS 6  SS 2  SS 4  SS 1 Most Robust burst profile =SS 1 ’s burst profile =0.5 bytes/sec.

9. Utility-Based Layer-Encoded Multicast Scheme M : Number of programs in the WiMAX networks N m : Number of subscribers for program m L m : Number of Layers for program m LmLm 1 2 3 Multicast Sub-session 01 Stream Data Rate of Layer 01= R 01 Multicast Sub-session L m Stream Data Rate of Layer L m = R L m

10. Utility-Based Layer-Encoded Multicast Scheme T : Network total available timeslot in a service period R s : Stream data rate of layer s R m (n) : Date rate of the burst profile able to serve n subscribers in program m Number of timeslots required to transmit this layer to n user Program m 43214321 SS 6 SS 2 SS 4 SS 1 Transmission Rate SS 1 = 0.5 bytes/sec SS 2 = 0.8 bytes/sec SS 6 = 1 bytes/sec SS 4 = 0.7 bytes/sec Example: Add Order SS 6  SS 2  SS 4  SS 1 Most Robust burst profile =SS 1 ’s burst profile =0.5 bytes/sec. Number of timeslots required to transmit 1st layer to 4 users

11. Utility-Based Layer-Encoded Multicast Scheme Utility value of each layer A user’s additional satisfaction when this layer is received Utility function is a stair-like function  out of the range of this paper Because the layer-encoded programs can only be decoded in order, the higher layer will not be assigned to users unless lower layers have already been assigned

12. Utility-Based Layer-Encoded Multicast Scheme Related Notations Marginal Utility :ΔT s (n) The time slots required to serve on additional user given that n users have already been served ΔT s (n) = T s (n+1)-T s (n) Marginal Utility of layer s : ΔU The average utility of ΔT s (n) time slots The bigger Marginal Utility of layer is, the higher the priority of layer is The additional utility value when a user receives layer s

13. SS 1 SS 2 SS 3 SS 4 SS 5 SS 6 SS 7 SS 8 SS 9 SS 10 Step 1. The system pick up all compulsory layers and serves them first Ex. Base layer Step 2. For each layer, find an unserved user who has best channel quality and is likely to be served  from lower layers to high layer until no available resource

14. Simulation Result Simulation Parameters Data Rate of each user’s burst profile R m (n) is uniformly distributed over [0.1,0.2,…,0.9,1] Number of programs = 2 programs Each program has 4 layers The rate of each layer R s is set to 1

15. Simulation Result

19. Conclusion This paper proposed a utility-based resource allocation scheme, called U-LEM, for layer-encoded multicast streaming service in WiMAX networks. Polynomial time Future works Scheduling algorithm Call admission control

20. Thank You !!