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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
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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, China 2Institute of Computing Technology, Chinese Academy of Sciences, China 3Wireless 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)
Channel quality dependent rate-limited Scheduling ( CD-RL ) Basic scheduler Extended scheduler Order changing in CD-RL
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 ihasn’t been satisfied withminimum reserved traffic rate till the nth frame
Basic scheduler • Tstart(i) is introduced as a timestamp to record the first time service flow ireceives 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 data quantity minimum reserved traffic rate maximum data quantity the time in frame n
Basic scheduler • Real-time scheduler Data transmission size for service flow iwith s slotsremaining in frame n real-time data expiring in next frame real data quantity of service flow i maximum data transmission size for service flow iin 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 iin 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 Fkin 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 Starvation flag Q2,k
Order changing in CD-RL Q1,k Starvation flag Full flag Half-full flag Sorting by channel quality Q2,k Full flag:satisfied with maximum sustained traffic rates
Order changing in CD-RL Q1,k Starvation flag Full flag Half-full flag Q2,k Full flag:satisfied with maximum sustained traffic rates
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