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Channel Quality Dependent Rate-limited Scheduling Algorithm for IEEE 802.16 Wireless Networks. Cuicui Zhao 1 , Jinlong Hu 2 , Jihua Zhou 2 , Jinglin Shi 2 , Eryk Dutkiewicz 3 1 Graduate University of Chinese Academy of Sciences, Beijing, China - PowerPoint PPT Presentation
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Channel Quality Dependent Rate-limited Scheduling Algorithm for IEEE 802.16 Wireless Networks
Cuicui Zhao1, Jinlong Hu2, Jihua Zhou2, Jinglin Shi2, Eryk Dutkiewicz3
1Graduate University of Chinese Academy of Sciences, Beijing, China2Institute of Computing Technology, Chinese Academy of Sciences, China3Wireless Technologies Laboratory, University of Wollonggong
IEEE CMC 2009
Outline
Introduction Related Works Goal
Channel quality dependent rate-limited Scheduling Basic scheduler Extened scheduler Order changing in CD-RL
Simulation Results Conclusions
Introduction
In IEEE 802.16, five data delivery services are defined unsolicited grant service (UGS) real-time variable-rate (RT-VR) extended real-time variable-rate (ERT-VR) non-real-time variable-rate (NRT-VR) best effort (BE)
The standard does not recommend any particular scheme in detail
Background
IEEE 802.16 service classes
n
Introduction
Related Works Deficit round-robin (DRR) [8]
To allow handling variable packet sizes in a fair manner
Low complexity Channel-quality dependent earliest deadline due
(CDEDD) [12] guarantees the targeted delay bounds and ensures that
the number of packets dropped is fairly distributed among users
High complexity
Introduction
Problem How to satisfy the basic QoS requirements, such as
the minimum reserved traffic rate and the maximum latency
How to allocate the rest bandwidth
Goal To satisfy the basic QoS requirements To enhance throughput Low complexity Based on fairness (BE is exclude)
Basic schedulerExtended schedulerOrder changing in CD-RL
Channel quality dependent rate-limited Scheduling ( CD-RL )
Scheduler structure
Basic scheduler
In priority class Fk, service flows are served in descending order of starvation(i,n), which is defined as how long service flow i hasn’t been satisfied with minimum reserved traffic rate till the nth frame
Basic scheduler
Tstart(i) is introduced as a timestamp to record the first time service flow i receives data from upper layer
Quantity of data that have been sent from Tstart(i) to the nth frame
Sending data in the nth frame
Basic scheduler
minimum reserved traffic rate
minimum data quantity
the time in frame nmaximum data quantity
Basic scheduler
Real-time scheduler
real-time data expiring in next frame
Data transmission size for service flow i with s slots remaining in frame n
real data quantity of service flow i
maximum data transmission size for service flow i in frame n with s slots remaining
Basic scheduler
Non-real-time scheduler
real data quantity of service flow i
maximum data transmission size for service flow i in frame n with s slots remaining
Extended scheduler
priorities from highest to lowest are ERT-VR, RT-VR, NRT-VR, and BE.
To allocates bandwidth to service flows of class Fk in descending order of c(i,n)
Order changing in CD-RL
Q1,k
Q2,k
Order changing in CD-RL
Q1,k
Q2,k
Order changing in CD-RL
Q1,k
Q2,k
Starvation flag
Order changing in CD-RL
Q1,k
Q2,k
Starvation flag
Full flag
Full flag: satisfied with maximum sustained traffic rates
Sorting by channel quality
Half-full flag
Order changing in CD-RL
Q1,k
Q2,k
Starvation flag
Full flag
Full flag: satisfied with maximum sustained traffic rates
Half-full flag
Simulation Results
number of slot S for data transmission is assumed to be 300 per frame
Frame duration is 5 ms
Simulation Results
Throughput of RT-VR service
Simulation Results
Fairness of RT-VR service
Simulation Results
User satisfied rate of RT-VR service
Simulation Results
Average Packet Delay of RT-VR servic
Conclusions
CD-RL provides service in class priority with guaranteed data rate while taking throughput enhancement into accoun
CD-RL can be implemented with low complexity
Simulation results show that CD-RL has good performances in fairness, minimum reserved traffic rate and average packet delay
Thank you