advanced mechanisms for sleep mode optimization of voip traffic over ieee 802.16m

Advanced Mechanisms for Sleep Mode Optimization of VoIP Traffic over IEEE

802.16m

IEEE Globecom 2010

Ritesh K. Kalle, Maruti Gupta, Aran Bergman, Elad Levy, Shantidev Mohanty, Muthaiah Venkatachalam and Debabrata Das

Speaker: Wun-Cheng Li

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

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Introduction• IEEE 802.16m standard provide VoIP traffic services over

WiMAX channels.

• VoIP traffic is uniquely characterized by small packets sent regularly at periodic.

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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

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Introduction• Three IEEE 802.16e/m power saving classes

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…

TS_init

2 x TS_init TL

(TS_max)

TL TS

…

TS

normal operation

sleep windows

listening windows

Type I :

Type II :

Type III :

Introduction• Three IEEE 802.16m power saving classes

▫ Type IV

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Introduction• A typical VoIP session is a two-way conversation

characterized by silence and talk periods.

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A B

A B

A B

A B

Talks

Silent

Introduction• A typical VoIP session is a two-way conversation

characterized by silence and talk periods.▫ Let Pij represent the probability of transition from state i to state j.

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Goal• The proposed VoIP Specific Advanced Power Saving

Mechanisms reduces the average power consumption

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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

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DL Subframe

UL Subframe

DL Sleep

UL Sleep

DL MAP HARQ FB

Listening Window Sleeping Window

UL VoIP

DL:UL 4:4 subframes

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

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HARQ FBDL MAP

UL VoIP

Listening Window Sleeping Window

DL:UL 4:4 subframes

DL Subframe

UL Subframe

DL Sleep

UL Sleep

VOIP Specific Advanced Power Save Mechanisms

• Discrete Listening Window Extension (DLWE)

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DL MAP HARQ FB

UL VoIP

DL:UL 4:4 subframes

DL Subframe

UL Subframe

DL Sleep

UL Sleep

NAK + DL MAP

HARQ FB

ACK + DL MAP

UL HARQ Retx

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.

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Simulation• MATLAB

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Parameter SettingsIEEE 802.16m Frame Time 5 msUL: DL ratio 5:3Max. no. of HARQ retransmissions (RTT =5 ms) 4VoIP codec AMRTotal number of VoIP users 200Length of AAI_SLP-REQ/ AAI_SLP-REQ 64/80 bitsLength of SCH/SCEH 24 bitsTotal simulation time 2000 s

Simulation

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Simulation• Sleep Cycle

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Simulation• Signaling Overhead

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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.

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Thank you!

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