Power control Considerations and framework for MS-MS Communications IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C802.16n-11/0108 Date Submitted: 2011-07-10 Source: Eldad Zeira Voice: InterDigital E-mail: eldad.zeira@interdigital.com Venue: IEEE 802.16n at session #74 responding to call for comments for AWD issued after #73 Base Contribution: N/A Purpose: To be discussed and adopted by 802.16n 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: <http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and <http://standards.ieee.org/guides/opman/sect6.html#6.3>. Further information is located at <http://standards.ieee.org/board/pat/pat-material.html> and <http://standards.ieee.org/board/pat >. 1

Power control Considerations and framework for MS-MS Communications Eldad Zeira, InterDigital

MS-MS communication needs to be power controlled Massive resource reuse is a necessary condition to achieving high cell throughput AWD recognizes this and allows HR-BS to schedule two or more MS-MS or MS-BS transmissions in same resources Proper power control is essential in achieving spatial separation while maintaining each link quality

Design goals of power control procedures Find power level that is close to the optimal as described above Require little signaling overhead but retain HR-BS over-all control Be easy to compute, especially by the forwarding HR-MS for which this is an extra burden I.e. it is an addition to its own operation Treat both repetitive and one-of transmissions, BUT This paper treats power control for “repetitive” transmissions only non-repetitive transmissions (e.g. ranging) out of scope for this contribution

System design affects choice of power control procedure Resource allocation: centralized, distributed & hybrid In “Hybrid” we use a combination of persistent and dynamic. This is baseline assumption in AWD. Forwarding mode: “simple” or “cooperative” Simple assumed in AWD. Frame structure: location of MS-MS link (crosslink, or XL. MS-BS links are “traditional” links, or TRL) UL only (other than e.g. some signals required for HR-MS discovery?) DL only (no proposal for this case) UL/DL, similar to ARS operation

Power control procedures: 802.16m For data channels (incl. MAC messages) SINRTarget is the target UL SINR needed at receiving MS P is the TX power level (dBm) per stream and per subcarrier for the current transmission L is the estimated average current DL propagation loss NI is the estimated N+I at receiving MS. Offset is a correction term. SINRMIN(dB) is for minimum rate expected by ABS. γIoT is the fairness and IoT control factor broadcasted. SIRDL is the linear ratio of the downlink signal to interference power. α depends on the number of receive antennas at receiving MS. β is set to one to account for number of streams. TNS is the total number of streams

Power control procedures: 2009 ([2] 8.4.10.3) Closed loop PC Open loop PC

Use cases and interference mechanisms for MS-MS: transmissions in UL only In left of figure, MS (1) and (2) communicate on the XL while under BS control. In right of figure, MS (4) forwards data for MS (5). Both TRL (2)-BS and XL (1) – (2) interfere with TRL (3)-BS and XL (4)-(5). MS (5) transmitting on XL may or may not cause interference to other TRL but does interfere with XL

PC considerations for XL in UL: - Both HR-MS attached DC or FTN HR-BS controlled Transmission to HR-BS: Control by the HR-BS Open or closed loops or both? Use of Offset? Control rate / measurements? Proper use of baseline procedures (i.e. 2009 or 802.16m-D12) Transmission to another HR-MS Control by HR-BS allows use of same procedures with receiving HR-MS reporting to HR-BS As above, either use of Offset or 802.16m-like procedures can be utilized

PC considerations for XL in UL: - One HR-MS attached DC or FTN Forwarding HR-MS: transmitting on TRL should be same as previous case Transmitting on XL – power control done strictly from HR-BS would need much signaling (forwarded through same) – how to reduce overhead while retaining HR-BS control ? Forwarded HR-MS may or may not be in a position to cause interference on TRL, but XL interference assumed. Forwarded HR-MS receives power control commands from forwarding HR-MS. Are these generated by HR-MS or by HR-BS (and forwarded)? Do we want to create 2 procedures (w and without TRL interference)? Reducing overhead while retaining HR-BS control

PC considerations for XL in UL: - No HR-MS attached This case should be handled like the MS-BS link in baseline. If a coordinator is used then it takes the role of the HR-BS in: Controlling its own power using measurements and reports it may request from the non-coordinating HR-MS Controlling the non-coordinating HR-MS as an HR-BS would

Interference mechanisms for MS-MS: transmissions in both UL and DL. The following interference mechanisms exist: interference of UL TRL to BS reception (normal cellular interference) interference of UL TRL to XL TPSS to FPSS transmission interference of UL XL (TPSS transmission) to BS reception on TRL Interfere of DL XL (FPSS transmission) to MS reception on TRL Interfere of DL XL (FPSS transmission) to MS reception on XL

PC considerations for XL in UL/DL: Note slightly different interference mechanisms TRL transmissions (to HR-BS) is always in UL, therefore same procedures can be applied. Applies to the cases of single HR-MS and both HR-MS associated Forwarded HR-MS power control Same interfere mechanisms as for UL only therefore same procedures could apply Also applies to the cases of single HR-MS and both HR-MS associated Power control for forwarding HR-MS transmitting on XL in DL direction This is really a new scenario, however - May use identical procedure to that used for UL only (except for definition of resources for measurements etc.)

Text for 2009 based amendment Insert at the end of 8.4.10: 8.4.10.4 Power control for mobile to mobile communication 8.4.10.4.1 Power control for two HR-MS associated with an HR-BS When two HR-MS that are associated with an HR-BS are transmitting to each other their power control related commands are generated by their serving HR-BS. The HR-BS may define measurements to be performed by the HR-MS on resources used for MS-MS communications and on the desired MS-MS signal to be reported to the HR-BS. Definition of power control procedure is TBD.

Text for 2009 based amendment - cont’d 8.4.10.4.2 Power control for one HR-MS associated with an HR-BS The transmission power of a forwarding HR-MS transmitting to the HR-BS is controlled by it. The transmission power of a forwarding HR-MS transmitting to forwarded HR-MS is controlled by messages from the forwarded HR-MS that are derived from HR-BS controls The transmission power of a forwarded HR-MS is controlled by messages from the forwarding HR-MS that are derived from HR-BS controls Power control procedure details TBD

Text for 2009 based amendment - cont’d 8.4.10.4.3 Power control for no HR-MS associated with an HR-BS If a coordinator is used then it controls transmission power for the pair in the same way as a baseline HR-BS would, i.e. it - Controls its own power using measurements and reports it may request from the non-coordinating HR-MS. - Controls the power of the non-coordinating HR-MS as an HR-BS would.

Text for 802.16m based amendment Insert at the end of 16.3.8: 16.3.8.6 Power control for mobile to mobile communication 16.3.8.6.1 Power control for two HR-MS associated with an HR-BS When two HR-MS that are associated with an HR-BS are transmitting to each other their power control related commands are generated by their serving HR-BS. The HR-BS may define measurements to be performed by the HR-MS on resources used for MS-MS communications and on the desired MS-MS signal to be reported to the HR-BS. Definition of power control procedure is TBD.

Text for 802.16m based amendment- cont’d 16.3.8.6.2 Power control for one HR-MS associated with an HR-BS The transmission power of a forwarding HR-MS transmitting to the HR-BS is controlled by it. The transmission power of a forwarding HR-MS transmitting to forwarded HR-MS is controlled by messages from the forwarded HR-MS that are derived from HR-BS controls The transmission power of a forwarded HR-MS is controlled by messages from the forwarding HR-MS that are derived from HR-BS controls Power control procedure details TBD

Text for 802.16m based amendment- cont’d 16.3.8.6.3 Power control for no HR-MS associated with an HR-BS If a coordinator is used then it controls transmission power for the pair in the same way as a baseline HR-BS would, i.e. it - Controls its own power using measurements and reports it may request from the non-coordinating HR-MS. - Controls the power of the non-coordinating HR-MS as an HR-BS would.

References [1] 802.16m amendment (D12) [2] 802.16 “2009” [3] UL open loop PC recommendations IEEE s802.16m-09/0546