Advanced Mechanisms for Sleep Mode Optimization of VoIP Traffic over IEEE 802.16m

1. Advanced Mechanisms for Sleep Mode Optimization of VoIP Traffic over IEEE 802.16m Ritesh K. Kalle, Maruti Gupta, Aran Bergman, Elad Levy, ShantidevMohanty, MuthaiahVenkatachalam and DebabrataDas Speaker: Wun-Cheng Li • IEEE Globecom2010

2. Outline • Introduction • Goal • VoIP Specific Advanced Power Save Mechanisms • Sub-frame level sleep operation • Discrete Listening Window Extension (DLWE) • Different sleep cycle configuration for active and inactive periods • Simulation • Conclusion

3. Introduction • IEEE 802.16m standard provide VoIP traffic services over WiMAX channels. • VoIP traffic is uniquely characterized by small packets sent regularly at periodic.

4. Introduction • Power saving is a critical issue for mobile wireless devices • Mobile devices are normally battery-operated • In IEEE 802.16m, four power saving types are defined for different connections with the specific QoS requirement

5. TL TS … TS Introduction • Three IEEE 802.16e/m power saving classes TS_init (TS_max) … Type I : 2 x TS_init TL Type II : normal operation Type III : sleep windows listening windows

6. Introduction • Three IEEE 802.16m power saving classes • Type IV

7. Introduction • A typical VoIP session is a two-way conversation characterized by silenceand talkperiods. A B A B A B A B Talks Silent

8. Introduction • A typical VoIP session is a two-way conversation characterized by silenceand talkperiods. • Let Pijrepresent the probability of transition from state i to state j.

9. Goal • The proposed VoIP Specific Advanced Power Saving Mechanisms reduces the average power consumption

10. VOIP Specific Advanced Power Save Mechanisms • Sub-frame level sleep operation • The MAP information is sent during every DL sub-frame • MS has to remain awake for the entire duration of DL sub-frames DL:UL 4:4 subframes ULVoIP DLMAP HARQ FB Sleeping Window Listening Window DL Subframe DL Sleep UL Subframe UL Sleep

11. VOIP Specific Advanced Power Save Mechanisms • Sub-frame level sleep operation • Limiting the MS to remain awake sub-frames • MAP information elements (IEs) • VoIP traffic • HARQ control DL:UL 4:4 subframes ULVoIP DLMAP HARQ FB Sleeping Window Listening Window DL Subframe DL Sleep UL Subframe UL Sleep

12. VOIP Specific Advanced Power Save Mechanisms • Discrete Listening Window Extension (DLWE) DL:UL 4:4 subframes ULHARQ Retx ULVoIP DLMAP HARQ FB HARQ FB NAK + DL MAP ACK + DL MAP DL Subframe DL Sleep UL Subframe UL Sleep

13. VOIP Specific Advanced Power Save Mechanisms • Different sleep cycle configuration for active and inactive periods • Persistent allocation to reduce scheduling overhead which would reduce the activity period per frame to schedule the VoIP or SID packet.

14. Simulation • MATLAB

15. Simulation

16. Simulation • Sleep Cycle

17. Simulation • Signaling Overhead

18. Conclusions • This paper proposed novel mechanisms to substantially improve power savings for VoIP traffic in IEEE 802.16m. • These mechanisms lead to power savings of up to 70% and can improve further with sleep cycle adaptation for mutual silence periods.

19. Thank you!