1. Uplink Power Control Design - Considerations and Mechanism Document Number: S802.16m-08/813 Date Submitted: 2008-07-16 Source: DongCheol Kim, Jin Sam Kawk, Young-Hyoun Kwon Voice:+82-31-450-1916 Sungho Moon,and Wookbong Lee E-mail: {dongcheol.kim; samji; wishwill; msungho; wbong}@lge.com{dongcheol.kim; samji;wishwillmsungho; wbong}@lge.com LG Electronics Venue: IEEE 802.16m-08/024 "Call for Comments and Contributions on Project 802.16m SDD" Specific Topic: Power Control Base Contribution: IEEE C80216m-08_813 Purpose: To be discussed and adopted by TGm for use in the IEEE 802.16m SDD 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 IEEEs name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEEs 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. Introduction In this contribution, in order to design the uplink power control for 802.16m, we address some discussion points and propose a high-level UL PC mechanism by considering several key aspects and their impacts on the 802.16m system performance in terms of interference-level control, pathloss compensation, multi-user operation, control/data transmission, interference management including Fractional Frequency Reuse(FFR) operation, etc..

3. Consideration Points on Uplink Power Control Design Intra/Inter-Cell Power Control –Legacy power control in uplink is only focused on Intra-cell power control, but to control the inter-cell interference level strictly, Inter-cell power control should be supported in uplink power control for 16m Full or fractional path loss compensation –Frequency reuse factor is 1: Use full pathloss compensation –Frequency reuse factor isnt 1: May use full/fractional pathloss compensation[FFS] Separate power control between control and data channels –There are not same target and operating point between control and data channel. Open-loop or Closed-loop or Combined type of power control –Tight/effective power control with reduced power margin and overhead Power control with FFR mode –Support of the various channel characteristics in FFR operations

4. Power Control Mechanism for IEEE 802.16m The uplink transmit power level at a MS should be determined by considering the following features and functions for optimizing the intra- and inter- cell power control : Unified power control method combined with open- and closed-loop PC parameters Fractional pathloss compensation can be useful to reduce the IoT level from the neighboring cells as well as to increase the cell-edge user throughput with- out significantly sacrificing the overall system throughput. Simple inter-cell interference control by adding a parameter into the intra-cell power control operation Support of the IoT control by depending on the single- or multi-user transmission in the same resource units Applicable to the FFR modes for supporting the zone-specific interference and channel characteristic Efficient uplink power control for data and control transmission

5. Proposed Text for SDD x.y. Uplink Power Control The 802.16m power control shall support the following aspects in the uplink. Uplink power control supporting open- and closed-loop operation with reduced overhead and effective power adjustment Path-loss compensation: Full or/and fractional IoT control : Intra- or inter-cell interference control, multi-user support Separate power control operation for data and control Effective FFR mode support ------------------------------------------- Start of the Text ----------------------------------------------

6. The generic mechanism and parameters for the 802.16m power control can be embodied as follows: SINR Target Δ PowerAdjust δ PowerScaling Offset ICI PTx = αPL + NI + SINR Target + Δ PowerAdjust + δ PowerScaling + Offset ICI [dBm] (1) where –P Tx : Transmit power level at MS for achieving a given SINR Target with a desired MCS –α : Path-loss compensation factor with a range of 0 < α 1 (Default: α = 1) –PL : Downlink/Uplink pathloss estimate calculated at BS/MS –NI : Noise and interference level per subcarrier at BS –SINR Target : Target SINR threshold for each MCS level –Δ PowerAdjust : User specific power correction value from BS –δ PowerScaling : Power scaling factor according to the single- or multi-user transmission power level –Offset ICI : User-/cell-/group-specific [FFS] power adjustment value related to the inter-cell power control P Tx is the user transmit power level per subcarrier/resource unit, i.e., power spectral density, which is a function of the user power class and the assigned transmission bandwidth. The total of user transmit power can not exceed the predefined user transmit power class in the 802.16m system. Basically, the power control scheme in (1) supports the transmit power control by compensating the full/fraction of the pathloss, i.e., 0 < α 1 for the flexibility in balancing spectral efficiency and cell edge performance. Furthermore, the intra cell power control is defined by combining with open loop and closed loop operation. Additionally, it can easily extend to inter-cell power control using Offset _ICI, for controlling the inter-cell interference level. The noise and interference level measured at BS can be broadcasted to all users in corresponding serving cell for achieving the target SINR for a given MCS. Power correction parameter can be also used to adjust the transmit power level by compensating the estimation errors or inaccuracy in the fast channel varying, practical measurements, open-loop related components, etc. -------------------------------------------- End of the Text ----------------------------------------------------