MU MIMO Overview And Setup 80 Y8113 11 Guide
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80-Y8113-11 Rev. G
MU-MIMO Overview and Test Setup
Scope: QCA61x4A, QCA65x4, QCA937x, WCN3680, WCN39xx
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Confidential and Proprietary –Qualcomm Technologies, Inc.
NO PUBLIC DISCLOSURE PERMITTED: Please report postings of this document on public servers or websites to: DocCtrlAgent@qualcomm.com.
Restricted Distribution: Not to be distributed to anyone who is not an employee of either Qualcomm Technologies, Inc. or its affiliated companies without the express approval of Qualcomm Configuration
Management.
Not to be used, copied, reproduced, or modified in whole or in part, nor its contents revealed in any manner to others without the express written permission of Qualcomm Technologies, Inc.
Qualcomm is a trademark of Qualcomm Incorporated, registered in the United States and other countries. Other product and brand names may be trademarks or registered trademarks of their respective owners.
This technical data may be subject to U.S. and international export, re-export, or transfer (“export”) laws. Diversion contrary to U.S. and international law is strictly prohibited.
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Revision
Date Description
A October 2014
Initial
release
B April 2015
Updated
document title. No change to content
C August 2015
Updated slides
13,14,18 and 19
D September 2015
Changed
document title and added scope. Added section title for test setup and modified slide set.
E November 2015
Deleted slide
13, MU-MIMO configuration. Added slide for “MU-MIMO capability on association request (client
side)”.
On “MU gain in controlled environment” (slide 20), deleted MU-MIMO disabled/enabled columns in table.
F August 2016
Added WCN39xx in scope
G February 2017
Modified
tables on slides 17 and 18
Revision History
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Agenda
MU-MIMO Overview 5
MU-MIMO overview for WCN39xx 6
Beamforming overview 7
Benefits of MU-MIMO (vs. single-user) 8
802.11ac IEEE vs. current vs. Release 2 features 9
MU-MIMO high-level architecture 10
MU-MIMO high-level design 11
Feature interaction 12
Test Setup 13
Test topology 14
Test procedure 15
MU-MIMO capability on beacon (AP side) 16
MU-MIMO capability on association request (client side) 17
iPerf commands used for WCN3680 throughput tests 18
iPerf commands used only for QCA61x4A/QCA65x4/QCA937x throughput tests 19
IxChariot setup 20
MU gain in controlled environment 21
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MU-MIMO Overview Section 1
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•Multiple-input and Multiple-output (MIMO): A system that uses multiple antennas at both
the transmitter and receiver to improve communication performance
•SU-MIMO: Process of transmitting one or more streams to one user at-a-time
•MU-MIMO: Process of transmitting one or more streams to more than one user at-a-time in
the same set of frequency
MU-MIMO overview
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Beamforming overview
AP
•STA estimates channel and informs AP
•AP performs TxBF
Single-User TxBF
Explicit Beamforming
measure
DL TxBF
•Requires beamforming in client
•Optimized TxBF to 802.11ac
client
•Potential improved mid-range
performance for 802.11ac clients
Signal
AP
AP
AP
•AP estimates channel
•AP performs TxBF
Legacy/Implicit Beamforming
UL
•Does not require 802.11ac beamforming
•Potential improved mid-range
performance for legacy and 802.11ac
clients
DL TxBF
Signal
measure
AP
Single-User TxBF
•All STAs in the group estimate channels and inform AP
•AP performs Resource Allocation (Grouping, Rate Control) and TxBF
DLMulti-User MIMO
Multi-User Beamforming (for MU-MIMO)
AP
Signal
Null
Null
AP
MU-MIMO for
three STAs in group
•Requires high-precision beamforming
•Interference between clients limits grouping
•Requires complex resource allocation
measure
measure
measure
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•Supports multiple clients at the same time that improves overall DL throughput per
client
•With 2 to 3 times greater efficiency for MU clients, the network has more time or
capacity to serve other clients. This is required for enterprise network
Benefits of MU-MIMO (vs. single-user)
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802.11ac IEEE vs. current vs. Release 2 features
802.11ac Release 2
Mandatory:
Short GI
Optional:
4ss
MU-MIMO
160 MHz
802.11ac Release 1
Launch: June 2013
Mandatory:
80 MHz
1ss client/mobile AP
2ss AP
Optional:
3ss
TxBF
STBC, LDPC
IEEE 802.11ac
Features
Mandatory:
80 MHz
1ss client/mobile AP
2ss AP
Optional:
160 MHz, TxBF, MU-MIMO
STBC, LDPC
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MU-MIMO high-level architecture
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MU-MIMO high-level design
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•Note: From MAC software perspective, there should not be much impact on the existing
features. The MU-MIMO feature receives MU streams by decoding GID and user position
from the PLCP header, which is performed by PHY/MAC hardware.
Feature interaction
S. No. Feature interacting Behavior
1
P2P
MU
-MIMO is not supported in GO mode. The support exists in CLI mode if
GO supports
it.
2
Wi
-Fi and BT co-existence
Bluetooth
(BT) does not know if AP is using DL-MIMO. Therefore, there is
no
change in the behavior.
3
SAP mode
MU
-MIMO is not supported in SAP mode because the device has a single
antenna.
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Test Setup Section 2
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Test topology
Control PC
Gigabit
Ethernet
MU-MIMO
AP
•Use a MU-MIMO AP (for example, Linksys EA8500) with the latest image
Note: Use the latest image on AP.
•A control PC for the AP supports Gigabit Ethernet, either iperf or licensed IxChariot
•All STAs (support either 1x1 or 2x2) have iperf or IxChariot endpoint environment
Note: Download the iPerf or IxChariot application from Playstore
•Maintain 1 or 3 m away from AP to all STAs, and 1 m away between STAs
•AP and STAs are placed in isolated chambers or an open environment
STA 1
STA 2
STA 3
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Test procedure
1. Enable AP with 5 GHz, 80 MHz, and WPA2 (open) security.
2. Make sure MU-MIMO is enabled on AP and STAs by default.
3. Associate STAs with AP.
4. Run UDP DL and TCP DL peak TPUT between AP to STAs, simultaneously, on all STAs.
5. Capture the throughputs on the STAs (Rx).
6. Aggregate the throughput observed on all the STAs.
7. Compare the results with MU-MIMO disabled.
•Disable MU-MIMO mode from AP (or STA).
•MU-MIMO gain = (MU-MIMO-enabled throughput)/(MU-MIMO disabled throughput).
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MU-MIMO capability on beacon (AP side)
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MU-MIMO capability on association request (client side)
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iPerf commands used for WCN3680 throughput tests
Mode
Clients
Protocol iPerf commands (server) for AP
iPerf commands (client) for
STASpatial stream
VHT80
1SS + 1SS
UDP
iperf
–c <IP> -u –i 1 –f m –w 2M –t 300 –b
350M
iperf
–s -u –i 1 –f m –w 2M
TCP
iperf
–c <IP> –i 1 –f m –w 2M –t 300 –P 5
iperf
–s –i 1 –f m –w 2M
1SS + 1SS +
1SS
UDP
iperf
–c <IP> -u –i 1 –f m –w 2M –t 300 –b
3
20M
iperf
–s -u –i 1 –f m –w 2M
TCP
iperf
–c <IP> –i 1 –f m –w 2M –t 300 –P 5
iperf
–s –i 1 –f m –w 2M
VHT40
1SS + 1SS
UDP
iperf
–c <IP> -u –i 1 –f m –w 512k –t 300 –
b
20
0M
iperf
–s -u –i 1 –f m –w 2M
TCP
iperf
–c <IP> –i 1 –f m –w 512k –t 300 –P 5
iperf
–s –i 1 –f m –w 2M
1SS + 1SS +
1SS
UDP
iperf
–c <IP> -u –i 1 –f m –w 512k –t 300 –
b
20
0M
iperf
–s -u –i 1 –f m –w 2M
TCP
iperf
–c <IP> –i 1 –f m –w 512k –t 300 –P 5
iperf
–s –i 1 –f m –w 2M
VHT20
1SS + 1SS
UDP
iperf
–c <IP> -u –i 1 –f m –w 512k –t 300 –
b
70M
iperf
–s -u –i 1 –f m –w 2M
TCP
iperf
–c <IP> –i 1 –f m –w 512k –t 300 –P 5
iperf
–s –i 1 –f m –w 2M
1SS + 1SS +
1SS
UDP
iperf
–c <IP> -u –i 1 –f m –w 512k –t 300 –
b
70M
iperf
–s -u –i 1 –f m –w 2M
TCP
iperf
–c <IP> –i 1 –f m –w 512k –t 300 –P 5
iperf
–s –i 1 –f m –w 2M
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iPerf commands used only for QCA61x4A/QCA65x4/QCA937x
throughput tests
Mode Clients
Protocol iPerf commands (server) for AP
iPerf commands (client) for
STASpatial stream
VHT80
2
SS + 2SS UDP
iperf
–c <IP> -u –i 1 –f m –w 2M –t 300 –b
350M
iperf
–s -u –i 1 –f m –w 3M
TCP
iperf
–c <IP> –i 1 –f m –w 2M –t 300 –P 5
iperf
–s –i 1 –f m –w 3M
2
SS + 2SS + 2SS UDP
iperf
–c <IP> -u –i 1 –f m –w 2M –t 300 –b
3
20M
iperf
–s -u –i 1 –f m –w 3M
TCP
iperf
–c <IP> –i 1 –f m –w 2M –t 300 –P 5
iperf
–s –i 1 –f m –w 3M
VHT40
2
SS + 2SS UDP
iperf
–c <IP> -u –i 1 –f m –w 512k –t 300 –b
20
0M
iperf
–s -u –i 1 –f m –w 3M
TCP
iperf
–c <IP> –i 1 –f m –w 512k –t 300 –P 5
iperf
–s –i 1 –f m –w 3M
2
SS + 2SS + 2SS UDP
iperf
–c <IP> -u –i 1 –f m –w 512k –t 300 –b
20
0M
iperf
–s -u –i 1 –f m –w 3M
TCP
iperf
–c <IP> –i 1 –f m –w 512k –t 300 –P 5
iperf
–s –i 1 –f m –w 3M
VHT20
2
SS + 2SS UDP
iperf
–c <IP> -u –i 1 –f m –w 512k –t 300 –b
70M
iperf
–s -u –i 1 –f m –w 3M
TCP
iperf
–c <IP> –i 1 –f m –w 512k –t 300 –P 5
iperf
–s –i 1 –f m –w 3M
2
SS + 2SS + 2SS UDP
iperf
–c <IP> -u –i 1 –f m –w 512k –t 300 –b
70M
iperf
–s -u –i 1 –f m –w 3M
TCP
iperf
–c <IP> –i 1 –f m –w 512k –t 300 –P 5
iperf
–s –i 1 –f m –w 3M
Confidential and Proprietary –Qualcomm Technologies, Inc. |MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION |80-Y8113-11 Rev. G 20
1. Install the latest licensed IxChariot and UDP Rx only due to Chariot scripts issue on TCP.
2. Make 10 pairs per STA, approximately.
IxChariot setup
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Mode Scenarios Protocol MU-MIMO gain
VHT80
1SS + 1SS UDP 1.74
TCP 1.72
1SS + 1SS + 1SS UDP 2.43
TCP 2.32
2SS + 1SS UDP 1.71
TCP 1.70
2SS + 2SS UDP 1.29
TCP 1.23
2SS + 2SS + 2SS UDP 1.21
TCP 1.14
MU gain in controlled environment
•70 to 80% of lower performance is expected in an open environment while using
different AP
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Thank You
