Distributed Sounding Channel – Simulation Results Document Number: IEEE C802.16m-09/0749 Date Submitted: Source: Bishwarup Mondal, Fan Wang, Amitava Ghosh, Fred Vook Motorola * Venue: TGm – UL Control DG on UL Control Draft Amendment text Abstract: Simulation results showing the benefits of a distributed sounding channel Purpose: Show the benefits of including a distributed sounding channel design as an option in the AWD Notice: This document does not represent the agreed views of the IEEE 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 Patent Policy: The contributor is familiar with the IEEE-SA Patent Policy and Procedures: and. Further information is located at and.

2 of 9 C80216m-09_0749 Sounding Channel Design  Sounding symbol (current 16e / WiMAX)  Cell-edge users have noisy sounding  No time averaging of sounding  Contribution C082.16m-09/0707r1 proposes the addition of a distributed sounding channel as an additional sounding channel design option  Sounding channel distributed over an UL subframe  Sounding channel spans over 1 subframe (6 symbols)  Same overhead as sounding symbol in WiMAX  Cell-edge users can use 6x power per carrier compared to sounding symbol  Better inter-cell interference control (by cell-specific permutation)  Enables additional power boosting by stealing power from data  This contribution presents simulation results showing the benefits of a distributed sounding channel

3 of 9 C80216m-09_0749 Sounding Tile Design for Distributed Sounding Channel  Pattern A  Pattern B Sounding Pattern A that can coexist with 2-stream pilots for UL DRU 6x6 tile, 2-stream pilot pattern A for UL CRU 4-stream pilot pattern B for UL CRU and 2-stream interlaced pattern A(a) and A(b) for UL CRU Sounding Pattern B that can coexist with 2-stream pilots for UL DRU 6x6 tile, 4-stream pilot pattern B for UL CRU and 2-stream interlaced pattern A(c) for UL CRU

4 of 9 C80216m-09_0749 Coexistence with UL Data Transmissions  A subframe may contain a distributed sounding channel that coexists with data transmissions from AMSs assigned to transmit UL data within the subframe  Subframe contains either pattern A tiles or pattern B tiles  When allocating sounding in terms of PRUs, a “Sounding PRU” consists of three consecutive 6xNsym tiles in frequency  The sounding pilots do not overlap pilots transmitted by the AMSs assigned to transmit data on either an UL DRU or an UL CRU  Distributed sounding channel coexists with the uplink data transmissions within the same subframe  AMSs allocated to sound on the sounding tile transmits only on the sounding pilot locations  AMSs allocated to transmit data in the subframe that contains a distributed sounding channel do not transmit on the locations containing a sounding pilots The format of the subframe for data transmissions is effectively modified to work around the distributed sounding channel so that data transmissions do not overlap sounding transmissions.  Coexistence with SFBC data transmissions:  Option 1: if UL contains SFBC data transmissions, then sounding channel must be a single symbol  Option 2: We can re-define the SFBC symbol mapping since there is an even number of data tones in the tile, but the SFBC symbol pairings cannot always be over adjacent tones

5 of 9 C80216m-09_0749 SU Performance  SE for SU 4x2  2 ~ 3 dB gain on DL beamforming for cell edge users

6 of 9 C80216m-09_0749 MU Performance  SE for MU 4x2  ~1-2 dB gain on DL MU-MIMO for low-speed users

7 of 9 C80216m-09_0749 SU Link Simulation Parameters ParameterValue NFFT1024 Carrier frequency2.6 GHz # Tx antennas x #Rx antennas4 x 2 Antenna spacing4 λ for Tx, 0.5 λ for Rx MCS1/2 QPSK, 3/4 QPSK, 1/2 16QAM, 1/2 64QAM Channel modelSCM Urban Macro 15 0 Mobile speed3kmph UL sounding delay5ms (last sounding symbol to beamforming delay) DL PilotsDedicated, 2.5dB boosted Sounding Symbol parameters4.9dB per-subcarrier UL/DL SNR difference for a sounding band, 1Tx Antenna Sounded, Linear CE at BS, Rank-1 transmit weights are equal gain Sounding Channel (subframe)6.2dB – (7.8dB due to 6x power)=-1.6dB per-subcarrier UL/DL SNR difference for sounding channel, 1Tx antenna Sounded, Linear CE at BS, Rank-1 transmit weights are equal gain ReceiverMRC for Rank-1, LMMSE for Rank-2 DL channel estimator2D-MMSE based on 18x6 tile Packet size288/432/480 bits DL- AllocationLocalized allocation, 18x6 tile randomly distributed in frequency

8 of 9 C80216m-09_0749 MU Link Simulation Parameters ParameterValue NFFT1024 Carrier frequency2.6 GHz # Tx antennas x #Rx antennas4 x 2 Antenna spacing0.5 λ for Tx, 0.5 λ for Rx MCS1/2 QPSK, 1/2 16QAM, 1/2 64QAM Channel modelSCM Urban Macro 15 0 Mobile speed3kmph UL sounding delay10ms (last sounding symbol to beamforming delay) DL PilotsDedicated, 2.5dB boosted Sounding Symbol parameters5.9dB per-subcarrier UL/DL SNR difference for a sounding band, 1Tx Antenna Sounded Sounding Channel (subframe)-1.02dB per-subcarrier UL/DL SNR difference for sounding channel, 1Tx antenna Sounded ReceiverLMMSE DL channel estimator2D-MMSE based on 18x6 tile Packet size384/480 bits DL- AllocationLocalized allocation, 18x6 tile randomly distributed in frequency

9 of 9 C80216m-09_0749 Proposed Text for AWD  See Contribution C802.16m-09/0707r1 (or latest version)