doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Slide 1 Strawmodel ac Specification Framework Authors: Date:

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Introduction A draft 11ac specification framework is presented according to the spec framework methodology described in document 09/0237r0 Slide 2

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, ac Specification Framework Development Step 1: TGac specifies Key Technologies and Physical layer Parameters Step 2: TGac specifies Specification Framework according to Framework Specification Methodology Step 3: Form TGac Ad-hoc group(s) to work on Framework elements This document is a first attempt at steps 1&2 Slide 3

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Key Assumptions Build upon n as much as possible to increase probability of acceptance by the ac group –Use 11n MIMO-OFDM parameters for 20/40 MHz channels –same symbol time, number of subcarriers, subcarrier spacing, pilots, guard interval –Make data flow as close as possible to n –11ac MAC changes build upon EDCA –Ensure interoperability and coexistence with n Slide 4

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Preliminary Spec Framework; Topics for Consideration MU-MIMO –downlink / uplink / distributed –maximum number of users –maximum number of streams per user 500 Mbps single-user throughput target –synchronization –power control –channel state information feedback explicit channel state information feedback with more resolution than current 11n to accommodate higher required SNR for MU-MIMO Channel Bandwidth –Single User bandwidth (20/40/80 MHz) –Multi-channel - Non-contiguous groups of 20/40 MHz channels with synchronous or asynchronous transmission across channel groups –OFDMA –CCA Slide 5

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Preliminary 11ac PHY Block Diagram Slide 6

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Preambles Purpose –Provide training capability for timing, gain setting, frequency synchronization and channel estimation Required Inputs –Control parameters: preamble type, bandwidth, number of streams Expected Outputs –Preamble samples in frequency domain or time domain Proposed Performance Metrics –Length of preamble –Coexistence with 11a/n –Gain setting accuracy –PER versus SNR curves –Robustness to front-end impairments Dependencies –Choice of channel bandwidth, types of MU-MIMO, maximum number of spatial streams per user Possible Directions –Design mixed-mode and/or greenfield preambles to handle MU-MIMO and/or more than 4 spatial streams for a single user Slide 7

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Parsing and Interleaving Purpose –Parse and interleave data per user Required Inputs –Encoder output bits Expected Outputs –Interleaved bits Proposed Performance Metrics –PER versus SNR curves Dependencies –Choice of channel bandwidth and maximum number of spatial streams per user Possible Directions –Extend 11n interleaver for higher bandwidth and/or more than 4 spatial streams Slide 8

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Coding Purpose –Provide coding gain Required Inputs –Input bits Expected Outputs –Coded bits Proposed Performance Metrics –PER versus SNR curves –Coding/decoding complexity Dependencies –None Possible Directions –One option to reach the 500 Mbps single-user throughput would be to use a higher coding rate like 7/8 –Another choice to make is whether to keep encoding data per user as in 11n, or do per-stream coding Slide 9

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 STBC Purpose –Provide TX diversity Required Inputs –Frequency domain QAM subcarrier values per user Expected Outputs –STBC encoded subcarrier values Proposed Performance Metrics –PER versus SNR curves Dependencies –Maximum number of spatial streams per user Possible Directions –Extend 11n STBC for more than 4 spatial streams Slide 10

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Spatial Mapping and Cyclic Delays Purpose –Precode spatial streams in order to provide MU-MIMO or to provide TX diversity or beamforming in case of single-user transmission Required Inputs –Frequency domain subcarrier values Expected Outputs –Precoded frequency domain subcarrier values Proposed Performance Metrics –PER versus SNR curves Dependencies –Maximum number of users and maximum number of spatial streams per user Possible Directions –MMSE SDMA precoding –For single-user transmission, extend 11n cyclic delays for more than 4 spatial streams Slide 11

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Pilots Purpose –Phase reference within data symbols Required Inputs –Control parameters: number of streams, bandwidth Expected Outputs –Pilot values Proposed Performance Metrics –PER versus SNR curves Dependencies –Choice of channel bandwidth and maximum number of spatial streams per user Possible Directions –Extend 11n pilots for higher bandwidth and/or more than 4 spatial streams Slide 12

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Preliminary MAC Spec Framework Overview Slide 13 Downlink MU-MIMO Uplink MU-MIMO Multi-User Aggregation TDM/FDM Synchronous Contiguous Multi-channel Asynchronous Non-Contiguous Multi-channel Synchronous Non-Contiguous Multi-channel Distributed STA Communication Transmit Power Control Dynamic Frequency Selection Channel Switching Link Adaptation VHT Control FieldChannel Sounding Uplink and Downlink Block-Ack Flow ControlOBSS Management

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Downlink MU-MIMO Purpose –Enable efficient MU-MIMO for Downlink Data Transmission Required Inputs –NA Expected Outputs –Downlink MU-MIMO transmission protocol including Control Message sequence Frame formats and Field Descriptions Coexistence with 11a/n Proposed Performance Metrics –Maximum Downlink Data Throughput at the MAC SAP –Packet transfer latency from the Tx MAC SAP to Rx MAC SAP –Packet loss rate subject to application latency requirements –Peak-to-average power of transmitted signal Dependencies –Channel sounding protocol –Channel reservation protocol for multiple STAs –UL Block Ack for multiple STAs –VHT SIG Field Design Possible Directions –TBD Slide 14

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Uplink MU-MIMO Protocol Purpose –Enable efficient MU-MIMO for Uplink Data Transmission Required Inputs –NA Expected Outputs –Uplink MU-MIMO transmission protocol including Control Message sequence Frame formats and Field Descriptions Coexistence with 11a/n Proposed Performance Metrics –Uplink Data Throughput at the MAC SAP –Packet transfer latency from the Tx MAC SAP to Rx MAC SAP –Packet loss rate subject to application latency requirements Dependencies –Channel sounding protocol –Channel reservation protocol for multiple STAs –DL Block Ack transmission to multiple STAs –VHT SIG Field Design Possible Directions –TBD Slide 15

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Multiuser Aggregation TDM/OFDMA Purpose –Enable 20/40/80 MHz downlink/uplink transmission to/from multiple STAs Required Inputs –NA Expected Outputs –TDM/FDM Frame Format to support transmission to/from multiple STAs. –Control Message sequence, including CCA methodology. –Frame formats and Field Description. Proposed Performance Metrics –Maximum DL/UL Data Throughput at the MAC SAP –Packet transfer latency from the Tx MAC SAP to Rx MAC SAP –Packet loss rate subject to application latency requirements. Dependencies –VHT SIG Field design –Block ACK Scheduling Possible Directions –TBD Slide 16

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Synchronous Contiguous Channel Access Purpose –Enable synchronized uni-directional access on a set of contiguous channels Required Inputs –NA Expected Outputs –CCA for multiple contiguous channels –Protocols for assigning STAs to channels –Protocols for aggregating channels to a single STAs –Protocols for synchronizing uplink or downlink access on multiple channels. Proposed Performance Metrics –Uplink/Downlink Data Throughput at the MAC SAP –Channel usage efficiency –Packet transfer latency from the Tx MAC SAP to Rx MAC SAP –Packet loss rate subject to application latency requirements Dependencies –Multiuser Aggregation TDM/OFDMA Possible Directions –TBD Slide 17

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Synchronous Non-contiguous Channel Access Purpose –Enable synchronized bi-directional access on a set of non-contiguous channels Required Inputs –NA Expected Outputs –CCA for multiple contiguous/non-contiguous channels –Protocols for assigning STAs to channels –Protocols for aggregating channels to a single STAs –Protocols for synchronizing uplink/downlink access on multiple channels. Proposed Performance Metrics –Uplink/Downlink Data Throughput at the MAC SAP –Channel usage efficiency –Packet transfer latency from the Tx MAC SAP to Rx MAC SAP –Packet loss rate subject to application latency requirements Dependencies –TBD Possible Directions –TBD Slide 18

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Asynchronous Non-contiguous Multi-Channel Access Purpose –Enable an AP to support multiple asynchronous channels that are non- contiguous Required Inputs –NA Expected Outputs –Control Message sequence, including CCA Methodology –Frame formats and Field Description. Proposed Performance Metrics –Uplink/Downlink Data Throughput at the MAC SAP –Channel usage efficiency –Packet transfer latency from the Tx MAC SAP to Rx MAC SAP –Packet loss rate subject to application latency requirements Dependencies –VHT SIG Field design –Block ACK Scheduling Possible Directions –TBD Slide 19

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Distributed STA Communication Purpose –Enable simultaneous communication between multiple STA pairs using spatial or frequency separation Required Inputs –NA Expected Outputs –Protocol for co-ordinating communication between multiple STAs –Control Message sequence, including CCA Methodology –Frame formats and Field Description. Proposed Performance Metrics –Uplink/Downlink/Direct-link Data Throughput at the MAC SAP –Packet transfer latency from the Tx MAC SAP to Rx MAC SAP –Packet loss rate subject to application latency requirements Dependencies –11z TDLS Possible Directions –TBD Slide 20

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Transmit Power Control Purpose –Enable transmit power control at STA and AP for Power save UL MU-MIMO Required Inputs –NA Expected Outputs. –Transmit power control protocol Proposed Performance Metrics –Uplink MU-MIMO throughput –Packet transfer latency from the Tx MAC SAP to Rx MAC SAP –Packet loss rate subject to application latency requirements Dependencies –UL MU-MIMO Possible Directions –TBD Slide 21

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Dynamic Frequency Selection Purpose –Enable ac AP to select a suitable channel or set of channels for operation Required Inputs –NA Expected Outputs. –Frequency selection algorithm Proposed Performance Metrics –TBD Dependencies –Regulatory requirements 11a/11h Possible Directions –TBD Slide 22

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Channel Switching Purpose –Enable channel switching at STA and AP Required Inputs –NA Expected Outputs. –Protocols for AP controlled channel switching –Protocols for autonomous STA channel switching. Proposed Performance Metrics –Per STA uplink and downlink throughput –Channel utilization efficiency Dependencies –NA Possible Directions –TBD Slide 23

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Link Adaptation Purpose –Enable link adaptation for optimal MCS selection Required Inputs –NA Expected Outputs. –Signaling for link adaptation Proposed Performance Metrics –Uplink/Downlink Data Throughput at the MAC SAP Dependencies –DL/UL MU-MIMO protocols –Multichannel protocol Possible Directions –TBD Slide 24

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 Channel Sounding Protocol Purpose –Efficiently transmit channel sounding from multiple STAs to an AP Required Inputs –NA Expected Outputs. –Protocol for obtaining channel sounding from multiple STAs –Frame formats for control messages to obtain channel sounding. –Explicit/Implicit Sounding Frame Format Proposed Performance Metrics –Channel Sounding latency and time overhead Dependencies –DL and UL MU-MIMO protocols –Transmit power control Possible Directions –UL MU-MIMO for implicit channel sounding Slide 25

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 UL Block ACK Purpose –Enable efficient scheduling of UL Block ACKs from multiple STAs in response to a downlink MU-MIMO/TDM/FDM transmission Required Inputs –NA Expected Outputs –Resource allocation protocol for UL Block ACKs Proposed Performance Metrics –Block ACK time overhead Dependencies –DL MU-MIMO –TDM/FDM Possible Directions –MU-MIMO for UL Block ACK Slide 26

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 DL Block ACK Purpose –Enable efficient scheduling of DL Block ACKs to multiple STAs in response to an uplink MU-MIMO/TDM/FDM transmission. Required Inputs –NA Expected Outputs –Resource allocation protocol for DL Block ACK Proposed Performance Metrics –Block ACK time overhead Dependencies –UL MU-MIMO –TDM/FDM Multichannel protocols Possible Directions –MU-MIMO for DL Block Ack Slide 27

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 MAC Control Field Purpose –VHT MAC control field to be added to the MAC header to indicate parameters/signaling specific to ac Required Inputs –Downlink/Uplink MU-MIMO protocol –Multichannel protocol –Multi-STA block ack protocols Expected Outputs –Format of VHT MAC control field. Proposed Performance Metrics –VHT MAC Control Field Overhead (Bits) Dependencies –NA Possible Directions –Add VHT control field to header. Signal the presence of VHT control field through HT-control header. Slide 28

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 VHT Flow Control Purpose –Enable STA/AP to control the rate of packets arriving at it. Required Inputs –NA Expected Outputs –Flow control protocol Proposed Performance Metrics –Flow Control Time Overhead –Uplink/Downlink Data Throughput at the MAC SAP –Packet transfer latency from the Tx MAC SAP to Rx MAC SAP –Packet loss rate subject to application latency requirements Dependencies –NA Possible Directions –Ethernet pause packet protocol Slide 29

doc.:IEEE /0633r0 Submission Richard van Nee, Qualcomm May 14, 2009 OBSS Management Slide 30 Purpose –Preserve or increase the system throughput of OBSS's when compared to the case of n OBSS. Required Inputs –TBD Expected Outputs –OBSS management protocol Proposed Performance Metrics –Throughput and delay statistics of OBSS's in the presence of BSS Dependencies –Downlink/Uplink MU-MIMO protocol –Multichannel protocol Possible Directions - Protocol considering multichannel, MU-MIMO and aa OBSS protocols