1. LOGO A Latency and Modulation Aware Bandwidth Allocation Algorithm for WiMAX Base Stations Yi-Neng Lin, Che-Wen Wu, Ying-Dar Lin, and Yuan-Cheng Lai WCNC 2008

2. Outline  Introduction  Highest Urgency First (HUF)  Evaluation result  Conclusion

3. Introduction  WiMAX is an emerging next-generation mobile wireless technology  WiMAX has a control center named BS  Management  Allocation

4. Introduction  Bandwidth in wireless environment is relatively scarce  Demand of time-sensitive Multimedia Maximum latency Minimum reserved rate  An appropriate bandwidth allocation algorithm is required in BS

5. Introduction  MLWDF[5], IEEE Communication Magazine, Feb.2001, pp. 150-154  QoS  UPS[6], MILCOM Oct. 2003  UpLink  Starvation  DFPQ[7], ICC May 2005.  Only for per connection  TPP[8], Book, Current Technology Developments of WiMax Systems  It could lead to inappropriate grants owing to the proportion

6. Introduction  They do not concern the physical-layer characteristics  Modulation types and coding schemes (MCS)

7. Introduction  This paper  A bandwidth allocation algorithm Highest Urgency First(HUF) –QoS –UpLink/DownLink –MCS –Latency guarantee

8. Highest Urgency First  Divides the allocation procedure  Detemines the bandwidth of DL/UL subframe  Allocates bandwidth for data/bandwidth requests from MSs

9. Procedure of the Highest Urgency First

10. DL/UL Sub-frame Allocation 6ms 5ms =1 100byte 20byte/slot =5slot + + + + 10+13+5+24 12+15+4 = 52 31 x slots frame Pramble + DL/ULMAP S rem SD DL SD UL = (48-3*x)/2 x X=11.44 …

11. Highest Urgency First Allocation N i =20 slot P=4 D i =5 U-factor i = 20*(3+1) 5 N i =25 slot P=4 D i =5 U-factor i = 25*(4+1) 5 N i =20 slot P=4 D i =10 U-factor i = 20*(1+1) 5 …

12. Evaluation Results

18. Conclusion  Highest Urgency First  It translates the requested size to number of slots according to the current MCS  It Allocates the bandwidth according to the Urgency of the data/request  Simulation result indicates that the quality is retained as the MCS adapts owing to the link quality