Cisco Cisco Aironet 1850e Access Points 백서
IEEE 802.11ac Wave 2 AP’s: Cisco, Aruba, Ruckus
15
DR151120D
Copyright © Miercom 2015
5 February 2016
6 – Multi-User MIMO (MU-MIMO) vs Single-User (SU-MIMO)
Test Objective
Multi-Input, Multi-Output capability, or MIMO, has been supported in 802.11n and Wave 1
products, but in Single-User mode only (SU-MIMO). Multi-User MIMO, however, is a new feature
with Wave 2 – not supported by Wave 1 products. MU-MIMO support is required on both the
AP and the client device to work. MU-MIMO works on downstream data delivery, AP to client,
and allows an AP to transmit to multiple client devices simultaneously.
This test shows the throughput advantage of Multi-User MIMO over Single-User MIMO. The
tests start with 10 SU-MIMO clients, which are then replaced one at a time with MU-MIMO
clients. The gain in bandwidth is shown for each AP.
A second part of this test was to show how the different APs handle increasing MU-MIMO client
loads. To do this we run a throughput test for each AP with 10 MU-MIMO clients, then increase
it to 20 MU-MIMO clients, and finally 30.
How We Did It
The throughput gain metric for these tests is the aggregate TCP downlink throughput that ten
clients can realize, running MU-MIMO versus SU-MIMO. A second part of the testing, as noted,
compares the same, downlink TCP throughput for 10, 20 and 30 clients – first with their MU-
MIMO turned off, and then with MU-MIMO enabled.
Multi-Input, Multi-Output capability, or MIMO, has been supported in 802.11n and Wave 1
products, but in Single-User mode only (SU-MIMO). Multi-User MIMO, however, is a new feature
with Wave 2 – not supported by Wave 1 products. MU-MIMO support is required on both the
AP and the client device to work. MU-MIMO works on downstream data delivery, AP to client,
and allows an AP to transmit to multiple client devices simultaneously.
This test shows the throughput advantage of Multi-User MIMO over Single-User MIMO. The
tests start with 10 SU-MIMO clients, which are then replaced one at a time with MU-MIMO
clients. The gain in bandwidth is shown for each AP.
A second part of this test was to show how the different APs handle increasing MU-MIMO client
loads. To do this we run a throughput test for each AP with 10 MU-MIMO clients, then increase
it to 20 MU-MIMO clients, and finally 30.
How We Did It
The throughput gain metric for these tests is the aggregate TCP downlink throughput that ten
clients can realize, running MU-MIMO versus SU-MIMO. A second part of the testing, as noted,
compares the same, downlink TCP throughput for 10, 20 and 30 clients – first with their MU-
MIMO turned off, and then with MU-MIMO enabled.
As before, test traffic was generated and measured by the Ixia IxChariot test system.
One-for-one MU-MIMO.
First, for each Access Point, ten Single-User MIMO clients (ten iPhone 6s, each supporting a
single spatial stream) are throughput tested. Then, one SU-MIMO client is replaced with one
MU-MIMO client and the throughput is measured again. This is repeated until all ten clients (ten
Acer Aspire E15s) are MU-MIMO clients.
The APs were configured for 20-MHz channels. Traffic was TCP and aggregate downlink
throughput was measured – the environment that would most favor MU-MIMO vs SU-MIMO
operation.
First, for each Access Point, ten Single-User MIMO clients (ten iPhone 6s, each supporting a
single spatial stream) are throughput tested. Then, one SU-MIMO client is replaced with one
MU-MIMO client and the throughput is measured again. This is repeated until all ten clients (ten
Acer Aspire E15s) are MU-MIMO clients.
The APs were configured for 20-MHz channels. Traffic was TCP and aggregate downlink
throughput was measured – the environment that would most favor MU-MIMO vs SU-MIMO
operation.
Quantity
Client type
Wi-Fi Type
MU/SU MIMO
10
Acer Aspire E15 laptop
802.11ac, one Spatial Stream
MU-MIMO
10
iPhone 6 smartphone
802.11ac, one Spatial Stream
SU-MIMO
Test note: We were unable to get the Aruba AP-325 to work with the iPhone 6 SU-MIMO clients,
so we substituted Acer laptops with their MU-MIMO disabled for the Aruba AP tests. Our testing
has found the performance of the two clients – iPhone 6 and Acer E15, both running in SU-MIMO
mode – to be comparable.