A Power Saving Mechanism for IEEE 802.16e Networks

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A Power Saving Mechanism for IEEE 802.16e Networks

• Adviser Ho-Ting Wu
• Speaker Lei Yan

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Outlines

• Introduction to IEEE 802.16 and QoS
• Proposed power saving mechanism
• Motivation
• Related works
• Proposed bandwidth allocation algorithm
• Proposed packet scheduling algorithms
• Simulation results
• Conclusion and future works

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References

• 1 IEEE 802.16d-2004 and IEEE 802.16e-2005 Std.
• 2???. ???????????????. ???????. 2008
• 3 Min-Gom Kim, Minho Kang, and Jung Yul Choi,
  Performance Evaluation of the Sleep Mode
  Operation in the IEEE 802.16e MAC, Advanced
  Communication Technology, The 9th International
  Conference. Publication Date 12-14 Feb. 2007
  Vol. 1,  pp. 602-605
• 4 Kwanghun Han and Sunghyun Choi, Performance
  Analysis of Sleep Mode Operation in IEEE 802.16e
  Mobile Broadband Wireless Access Systems,
  Vehicular Technology Conference, 2006. VTC
  2006-Spring. IEEE 63rd Volume 3,  2006
  Page(s)1141 1145
• 5 Shengqing Zhu, Xiaoyu Ma, and Lujian Wang, A
  Delay-aware Auto Sleep Mode Operation for Power
  Saving WiMAX, Computer Communications and
  Networks, 2007. ICCCN 2007. Proceedings of 16th
  International Conference on 13-16 Aug. 2007
  Page(s)997 - 1001

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References (cont.)

• 6 Yan Zhang, Performance Modeling of Energy
  Management Mechanism in IEEE 802.16e Mobile
  WiMAX, Wireless Communications and Networking
  Conference, 2007.WCNC 2007. IEEE 11-15 March 2007
  Page(s)3205 - 3209
• 7 Min-Gon Kim, JungYul Choi, and Minho Kang
  Adaptive power saving mechanism considering the
  request period of each initiation of awakening in
  the IEEE 802.16e system,Communications Letters,
  IEEE Volume 12,  Issue 2, February 2008
  Page(s)106 - 108
• 8 Sanghvi, K., Jain, P.K., Lele, A., and Das,
  D., Adaptive waiting time threshold estimation
  algorithm for power saving in sleep mode of IEEE
  802.16e, Communication Systems Software and
  Middleware and Workshops, 2008. COMSWARE 2008.
  3rd International Conference on 6-10 Jan. 2008
  Page(s)334 - 340
• 9???. ???IEEE 802.16?????????????(IPSS
  Integrated Power Saving Scheduling Algorithm for
  IEEE 802.16 PMP Networks). ????????????????????.
  July, 2008

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References (cont.)

• 10 Shih-Chang Huang, Rong-Hong Jan, and Chien
  Chen, Energy efficient scheduling with QoS
  guarantee for IEEE 802.16e broadband wireless
  access networks, Proceedings of the 2007
  international conference on Wireless
  communications and mobile computing, pp. 547-552
• 11 Chia-Yen Lin and Hsi-Lu Chao, Energy-saving
  scheduling in IEEE 802.16e networks, 14-17 Oct.
  2008 Page(s)130 - 135
• 12 Chun-Hung Chen, Ho-Ting Wu, and Kai-Wei Ke,
  Predictive Credit Based Dynamic Bandwidth
  Allocation Mechanisms in Ethernet Passive Optical
  Network,, TENCON 2006. 2006 IEEE Region 10
  Conference, 14-17 Nov. 2006 Page(s)1 - 4

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Outlines

• Introduction to IEEE 802.16 and QoS
• Proposed power saving mechanism
• Motivation
• Related works
• Proposed BWA algorithm
• Proposed packet scheduling algorithms
• Simulation results (Unfinished)
• Conclusion and future works

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About IEEE 802.16

• Also called WiMAX (Worldwide Interoperability
  for Microwave Access)

Bandwidth
IEEE 802.15 IEEE 802.11 IEEE
802.16 3GPP
1 Gbps
802.15.3 High Speed Wireless PAN
Wi-Fi 802.11n
100 Mbps
WiMAX 802.16 (802.16-2004 802.16e)
Wi-Fi 802.11a/b/g
10 Mbps
4G 3G 2.5G
1 Mbps
802.15.1 Bluetooth
lt1m 10m 100m Up
to 50Km Up to 80Km
PAN
LAN
MAN
WAN
PAN Personal area networks MAN Metropolitan
area networks LAN Local area networks Wide area
networks
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About IEEE 802.16 (cont.)

• PHY S-OFDMA, MIMO, LDPC, and Space-Time Coding,
  etc
• Theoretical data rate and coverage 75Mbps and
  50km
• Fixed (802.16d) and mobile (802.16e) for SS
• Latest version 802.16m
• Opponents in last-mile DSL/FTTB/FTTH
• Opponent in the 4G candidate LTE
• Pros HI data rate (good for HQ multimedia
  services!) and robust to Doppler spread
• Cons LO indoor penetration

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Common Part Sublayer (CPS) Where our research
locates

• Responsible for multiple-access control
• Functions
• Connection establishment
• Connection maintenance
• Connection deletion
• Call admission control (CAC)
• Bandwidth request
• Bandwidth allocation (BWA)
• Packet scheduling

MAC Common Part Sublayer (MPC)
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Frame structure of WiMAX
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DL/UL behavior in a WiMAX frame

• DL-MAP BS lists the allocation time and size
  granted to MSs
• UL-MAP BS lists the order and size for BW
  requests by MSs

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Life-cycle of a connection (call)

• Phase 1 After ranging, according to the need of
  upper layers, MS uplinks a connection (call)
  request to BS, the BS accepts/rejects this call
  via CAC
• Phase 2 Although BW request is calculated by
  connections, BS grants data in the aspect of MS
  (packets granted in a batch) via BWA
• Phase 3 After the need ends, MS drops the call

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Life-cycle of a connection (call) (cont.)
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Two undefined parts in Standard

• 1. Packet scheduling The way for some purpose
  for BS to ADAPTIVELY arrange DL/UL orders for MS
  (but the de facto algorithm is not defined)
• 2. Power saving function The way for MS to
  ADAPTIVELY turn-off its RF devices (to sleep)
  at proper time (but the de facto algorithm is not
  defined)
• However, packet scheduling (BS initiated) can
  ALSO achieve power saving function (such as our
  research)!!

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Motivation of our research

• Reasons for power saving
• MASSIVE use of multimedia services runs out the
  battery fast
• The Tx/Rx power STILL costs a lot even though AMC
  is applied
• Initiation of power saving mode
• BS initiated (research after 2008, including
  ours)
• MS initiated (research before 2008)

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Service types and Power saving classes (PSC)

• Same type, different names!!

Service type Packet scheduling Power saving Proposes
UGS UGS UGS VoIP
ertPS ertPS ERTVR VoIP (silence suppression)
rtPS rtPS RTVR MPEG
nrtPS nrtPS NRTVR FTP
BE BE BE HTTP
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Service type and Power saving class (PSC) (cont.)

• The MS operation hierarchy in Std.
• In later pages we will modify the above

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Service type and Power saving class (PSC) (cont.)

• Three types of sleeping
• PSC I (HI delay bound) NRTVR and BE
• PSC II (LO delay bound) UGS and RTVR
• PSC III (LO delay bound) ERTVR
• Q Why ERTVR is listed in PSC III?
• A The silence suppression function keeps this
  call sleep longer

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Service type and Power saving class (PSC) (cont.)

• Sleep mode (PSC I to III) is shown below

• The physical sleep time for MS is the
  intersection among its ALL calls (very short!)

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Outlines

• Introduction to IEEE 802.16 and QoS
• Proposed power saving mechanism (PSM)
• Related works
• Motivation
• Proposed BWA algorithm
• Proposed packet scheduling algorithms
• Simulation results (Unfinished)
• Conclusion and future works

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Related works

• Categorize from 3 to 11
• Sleep time adaption in MS (only guess) 3-8
  MS predicts WHEN BS grants data, so there exists
  delays between predicted and actual time
• Scheduler categorizes MS by real-time/non
  real-time 9 So MS cannot have BOTH
• UGS only 10 and lack of ertPS 11
• Without BWA (except for 9)

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Outlines

• Introduction to IEEE 802.16 and QoS
• Proposed power saving mechanism (PSM)
• Related works
• Motivation
• Proposed BWA algorithm
• Proposed packet scheduling algorithms
• Simulation results (Unfinished)
• Conclusion and future works

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Motivation of our PSM

• Our design features
• Five service types (novelty)
• A traditional CAC algorithm
• A BWA algorithm for BS to ADAPTIVELY grants data
• Three packet scheduling algorithms for power
  saving
• Q Why we dont use the separated power saving
  func. from Std.?
• A From p.19, we thus need an integrated alm. to
  CENTRALLY arrange calls to prolong the MS sleep
  time.
• Q What is the benefit for above?
• A Reduction of frequent state transitions
  (overshoot at MS start-up)

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Outlines

• Introduction to IEEE 802.16 and QoS
• Proposed power saving mechanism (PSM)
• Related works
• Motivation
• Proposed BWA algorithm
• Proposed packet scheduling algorithms
• Simulation results (Unfinished)
• Conclusion and future works

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Dichotomy for MS states

• We modify the Std.-defined hierarchy into only 2
  states ON-state (RF device ON) and OFF-state (RF
  device OFF)

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Proposed BWA algorithm for a call

• Because data is allowed to be scheduled across
  frames in our design, we need to lower packet
  delay for each call, thus we have to estimate the
  ON-state time by estimating grant size
• Our scheduling algorithm allocates time for BR
  and BWA for the next scheduling cycle (gtframe
  duration)

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Proposed BWA algorithm for a call (cont.)

• Modified from 12, we wish to get a proper
  grant_size (Gk) at kth scheduling based on past
  experiences
• Parameters
• Scheduling cycle (obtained from scheduling alm.)
• buffer_size Size in BS and requested by MS
• grant_size Size granted by BS
• CAC_BW The BW that this call requested in CAC
• Credit Used to fine-tune the grant_size
• Estimated arrival rate during previous scheduling
  cycle

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Proposed BWA algorithm for a call (cont.)

• The BS sometimes NOT always grant sizes that a
  call exactly wants (so we use credit to /- the
  grant size)
• Formula (1) Credit (/-) is obtained by
  estimating the arrival rate (BW) for previous
  scheduling cycle, under the case that BS has
  known all data sizes it should grant next time
  (we can transform it into the current scheduling
  cycle duration)
• Formula (2) If the difference between buffer
  size is minus (the traffic flow is slowed down),
  then credit is minus

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Proposed BWA algorithm for a call (cont.)

• For rtPS/nrtPS/BE, the above criterions are
  applied
• For UGS/ertPS in a scheduling cycle, the BWA
  grants size of 64kbpsscheduling_cycle_duration
• Due to the constant transmission rate for
  UGS/ertPS, we can predict the scheduling cycle
  length much more precise than rtPS/nrtPS/BE

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Proposed BWA algorithm for a call (cont.)
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Outlines

• Introduction to IEEE 802.16 and QoS
• Proposed power saving mechanism (PSM)
• Related works
• Motivation
• Proposed BWA algorithm
• Proposed packet scheduling algorithms
• Simulation results (Unfinished)
• Conclusion and future works

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Three packet scheduling algorithms

• Design criterion (MS-based)
• Merge DL/UL time (for BR/BWA) to MS in ON-state
• Frame overflow is allowed
• No violation to the traffic delay bound
• The OFF-state time is the sleep time for MS
• Goal of the algorithms
• Simply ON-state time and OFF-state time
• No drastic packet dropping rate
• Prevent frequent ON-OFF switching (overshooting)
• Efficiently utilize DL/UL resource

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Parameters for MS

• Delay bound by service type (ms)
• DUGS
• DertPS
• DrtPS
• DnrtPS
• DBE
• TSi is the sleep time of MSi
• Scheduling cycle ??MS???call?????????,?????????
• traffic-cycle lt Dtraffic
• For example, R-cycleltDrtPS for rtPS traffics

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Algorithm 1 (Criterion)

• For any traffic, a call that firstly performs BR
  should be scheduled directly without computation
  of credits.
• Criterion 1 Split time into U-cycles (with delay
  bound of DUGS). Always allocate UGS/ertPS calls
  in the front
• Criterion 2 Allocate rtPS-gtnrtPS-gtBE for MS i
  into the remainder of U-cycle

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Algorithm 1 (Criterion) (cont.)

• Criterion 3 Once we cant allocate data size
  inside one frame duration, allocate the rest at
  next frame (see p.33)
• Criterion 4 As long as no violation for delay
  bound occurs, the remained data can be allocated
  in the next U-cycle
• Criterion 5 Drop the rest if the scheduling
  exceeds the traffic delay bound

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Algorithm 1 (Concentration for MS) (CONT.)

• Periodic UGSi/ertPSi (mandatory)
• Guarantee no delay for UGSi/ertPSi
• Concentrate rtPSi/nrtPSi/BEi for MSi
• Packets after delay bound should be dropped

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Flow chart for BWAscheduling
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Outlines

• Introduction to IEEE 802.16 and QoS
• Proposed power saving mechanism (PSM)
• Related works
• Motivation
• Proposed BWA algorithm
• Proposed packet scheduling algorithms
• Simulation results (Unfinished)
• Conclusion and future works

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Outlines

• Introduction to IEEE 802.16 and QoS
• Proposed power saving mechanism (PSM)
• Related works
• Motivation
• Proposed BWA algorithm
• Proposed packet scheduling algorithms
• Simulation results (Unfinished)
• Conclusion and future works

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Conclusion and future works

• Our novel research includes 5 traffic types
  CAC BWA Packet scheduling algorithms, which
  is more realistic than related works
• Our BWA adaptively and smartly helps BS grant
• The efficiency comparison among algorithms will
  be soon evaluated (packet dropping rate and sleep
  ratio, etc)

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Thank you for attention!!

• Really appreciate for your great comments!!