utility-based resource allocation for layer- encoded iptv multicast in ieee 802.16 (wimax) wireless...

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

Outline

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

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

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

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/8e3YvReference :

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.

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 multi

cast in wireless cellular networks,” in Proc.WiMob 2005.

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.

SS1 SS2 SS3 SS4

SS5 SS6 SS7

SS8 SS9 SS10

Suppose SS1, SS2, SS6, SS4 have the same Program m requests

Example:

Transmission Rate SS1 = 0.5 bytes/sec SS2 = 0.8 bytes/sec SS6 = 1 bytes/secSS4 = 0.7 bytes/sec

Add Order SS6 SS2 SS4 SS1

Most Robust burst profile=SS1’s burst profile=0.5 bytes/sec.


M : Number of programs in the WiMAX networksNm : Number of subscribers for program mLm : Number of Layers for program m

Lm

1

2

3

Multicast Sub-session 01Stream Data Rate of Layer 01= R01

Multicast Sub-session Lm

Stream Data Rate of Layer Lm = RLm


)(nR

RTT

m

ss

405.0

120

)4(1

1

mR

RTT

T : Network total available timeslot in a service periodRs : Stream data rate of layer sRm(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

4

3

2

1 SS6 SS2 SS4 SS1

Transmission Rate SS1 = 0.5 bytes/sec SS2 = 0.8 bytes/sec SS6 = 1 bytes/secSS4 = 0.7 bytes/sec

Example: Add Order SS6 SS2 SS4 SS1

Most Robust burst profile=SS1’s burst profile=0.5 bytes/sec.

Number of timeslots required to transmit 1st layer to 4 users


• 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


• Related Notations • Marginal Utility :ΔTs(n)

• The time slots required to serve on additional user given that n users have already been served

• ΔTs(n) = Ts(n+1)-Ts(n)

• Marginal Utility of layer s : ΔU• The average utility of ΔTs(n) time slots

•

• The bigger Marginal Utility of layer is, the higher the priority of layer is

s

s

T

UU

The additional utility value when a user receives layer s

SS1 SS2 SS3 SS4

SS5 SS6 SS7

SS8 SS9 SS10

Step 1. The system pick up all compulsory layers and serves them firstEx. 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

Simulation Result

• Simulation Parameters• Data Rate of each user’s burst profile Rm(n) is uniformly distributed ov

er [0.1,0.2,…,0.9,1]

• Number of programs = 2 programs

• Each program has 4 layers

• The rate of each layer Rs is set to 1

Simulation Result

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

Thank You !!

utility-based resource allocation for layer- encoded iptv multicast in ieee 802.16 (wimax) wireless...

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