1. Amendment Text Proposal for Section 10.5.3 on “Power Management for Connected Mode” Document Number: IEEE S802.16m-09/0553r1 Date Submitted: 2009-03-10 Source: N. Himayat, M. Venkatachalam, A. Koc, S. Talwar, H. Yin, Email: nageen.himayat@intel.com S. Ahmadi, M. Ho, R. Yang, Intel Corporation S. Andreev, P. Gonchukov, A. Turlikov, SUAI, St. Petersburg G. Miao, Ye (Geoffrey) Li, Georgia Tech. H. Kim, U. T. Austin Venue: Interim IEEE 802.16 Session #60, Vancouver, British Columbia, Canada Base Contribution: IEEE C80216m-09_0553r1.doc Purpose: Amendment text proposal for 802.16m AWD (IEEE 802.16m-09/0010) on Section 10.5 on “Power Management for Connected Mode.” In support of contribution C80216m-09_0553r1.doc Notice: This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.16. Patent Policy: The contributor is familiar with the IEEE-SA Patent Policy and Procedures: and.http://standards.ieee.org/guides/bylaws/sect6-7.html#6http://standards.ieee.org/guides/opman/sect6.html#6.3 Further information is located at and.http://standards.ieee.org/board/pat/pat-material.htmlhttp://standards.ieee.org/board/pat

2. Background Energy efficiency is critical for mobile communications due to limited improvements in battery technology and increasing demands of “any-time, anywhere” multimedia communication. Both 802.16m SRD and SDD include support for power management schemes. Section 10.5.3 added to the SDD to support power management in active connected mode in addition to idle and sleep modes. In active connected mode the base station (BS) can control transmission parameters (e.g. rate, power) as well as bandwidth allocation to save mobile (MS) energy during active transmission. This contribution proposes amendment text for Section 10.5.3, and shows gains in energy efficiency from employing energy savings techniques for active connected mode. Proposed text suggests minimal hooks in the standard to support BS controlled energy savings for active connected mode.

3. Recap: Approaches for Energy Savings (Transmit Mode) “Error free” Rate Exponential relationship between rate and power Linear relationship between rate and bandwidth Channel Gain Consider Shannon’s Law for a Point-to-Point Link For fixed rate channelUsers with good channel conditions can transmit with lower power bandwidthUsers with higher bandwidth can exponentially reduce power delay If delay can be tolerated, tradeoff delay and energy consumption Network can allocate power & bandwidth and control delay across users to conserve transmit energy

4. Energy-Aware Metrics Measure Energy Efficiency in terms of “Bits Per Joule” Aggregate Metrics Across Multiple Users Time Averaged Metrics Circuit Power Transmit RF power Instantaneous Energy-Aware Utility for User i Rate Time Averaged Utility Using Average Throughout and Average Power Fair Metric

5. Client Power Profile is Important Client circuit power consumption is a “fixed cost” during active mode conflicting design guidelines Need to balance conflicting design guidelines to optimize Transmit energy: Extend transmission time for as long as possible Circuit energy: Use highest rate supported and finish transmission quickly *Idle energy is also important in scheduling decisions Transmit Energy Overall Energy Circuit Energy Optimal Transmission

6. Reduced Complexity Energy-Efficient Solutions Goal: Optimize Time Averaged Metric Closed Form Solution for Link Adaptation Inverse of the Derivative of the SNR mapping function.Interference Allocation Metric for “Fair” Energy Efficient Scheduling Prop Fair MetricPower-Aware Part Pick user with best metric

7. Uplink Energy Efficiency Performance *Simulation assumptions in backup slides.

8. Minimal Standards Support Required Base station (BS) controls energy-efficient transmission parameters. The exact algorithm is vendor specific. Base station requires client power profile and power savings preference for selecting optimal transmission parameters: –Power profile information to be communicated upon initialization via MS capability exchange (SBC-REQ/RSP) messages. –Power profile includes MS circuit power (excess power in circuitry beyond the RF power required for reliable transmission) & Idle power consumption. –MS preferred energy savings mode (“on”, “off”). Reserved fields in the power control mode change messages PMC-REQ/RSP, are used to signal the energy savings mode. Existing power update mechanisms as specified in IEEE STD 8021.6 Rev2. D9 (section 8.4.10.3) may be used to control MS transmit power.

9. Recommended Amendment Text for Section 10.5.3 10.5.3 Power Management for the Connected Mode Enhanced power savings when the MS is in connected mode and is actively transmitting to the network may be supported in the network. In this mode, the base station may allocate resources and set transmission parameters to optimize energy savings at the MS. Various metrics may be used for measuring and optimizing active mode energy efficiency. An example metric to quantify energy efficiency is the “Bits-per-Joule” metric. 10.5.3.1 Required MS Capability Exchange To enable active mode energy savings, the MS will communicate its client power profile to the base-station. This information exchange can be performed during MS capability exchange upon initialization through the SBC-REQ/RSP MAC management messages (see 6.3.2.3.23 & 24 of [‎1]). A new TLV encoding specifying the MS Power Profile is defined for this purpose. The MS Power Profile will include an estimate of the MS circuit power consumption. The circuit power consumption in the transmit mode is the additional power consumed in the MS device electronics when the MS is actively transmitting to the network. The circuit power captures the power overhead of signal transmission beyond the RF power required to send the signal reliably to the BS. The MS may also report an estimate of the circuit power consumed in active receive mode, as well as the Idle power consumed when the MS is not communicating with the network. The encoding of the MS Power Profile TLV is given below. TypeLengthValueScope 2066Bits 0-7: Transmit Circuit Power (in steps of 10 dBm) Bits 8-15 Receive Circuit Power (in steps of 10 dBm) Bits 16-23 Idle Power (in steps of 5 dBm) Bits 24-47 Reserved SBC-REQ, SBC-RSP

10. Recommended Amendment Text for Section 10.5.3 (2) 10.5.3.2 Initiating Active Mode Energy Savings Either the MS or the BS may initiate active mode energy savings mode for the MS. The selection of this mode will be through slow updates using MAC management messages. Specifically, the PMC_REQ/RSP (Power Control Mode Change) mechanism defined in Section 6.3.2.3.54 of [‎1] will be used. The MS will use the existing 5 bit reserved field within the PMC-REQ message to initiate active mode energy savings. The exact changes to the PMC_REQ message are shown in bold text below. SyntaxSize (bit)Notes PMC_REQ message type {-- Management Message Type = 638Type =63 Power control mode change20b00: Closed-loop power control mode 0b01: Open loop power control passive mode with Offset_SSperSS retention. 0b10: Open-loop power control passive mode with Offset_SSperSS reset 0b11: Open-loop power control active mode UL TX power8UL TX power level for the burst that carries this header (11.1.1). When the Tx power is different from slot to slot, the maximum value is reported. Confirmation10: Request 1: Confirmation Energy savings mode10: Off 1: On Energy savings mode confirmation 10: Request 1: Confirmation Reserved3Shall be set to zero. }-

11. Recommended Amendment Text for Section 10.5.3 (3) 10.5.3.2 MS Power Update Mechanisms Existing open and closed loop power update mechanisms, as specified in section 8.4.10.3 of IEEE 802.16 [‎1] standard, shall be used to control the MS transmit power for energy efficient transmission.

12. Backup

13. System Level Simulation Assumptions System ParameterValues Cell geometry19 cell system w/ wrap around, 3 sectors, reuse 1 Intersite Distance500m Carrier Frequency2.5 GHZ System Bandwidth10 MHz (1024 FFT size) Power ControlEnergy-Efficient (EE), Fixed SINR target, Full-Power Number of Users/Sector10 SchedulingLow complexity Energy-Efficient w/ Geometric Average, Proportional Fair MIMO configuration1x2 Circuit Power, Idle Power100 mW, 10 mW Maximum Transmit Power23 dBm Channel ModelITU-Ped B, 3 kph Link to System MappingRBIR Link Adaptation Metric for EECapacity Based HARQEnabled Sub-channel PermutationPUSC

14. References 1.IEEE STD 802.16, Rev2, D9, Jan. 2009. 2.IEEE 802.16m-09/0010, “802.16m Amendment Working Document,” (AWD). 3.IEEE 802.16m-07/002r8, “802.16m Systems Requirements Document,” (SRD). 4.IEEE 802.16m-08/003r7, “802.16m System Description Document,” (SDD). 5.N. Himayat et. al., “Improving client energy consumption in 802.116m,” C802.16m-09/107r6, Jan. 2009. 6.R. Yang, A. Koc, et. al, “Uplink open loop power control recommendation for IEEE 802.16m amendment,” IEEE C80216m- 09_0546r1, March 2009.