WISEWiTS Intensive Studies Extension

CCA Preamble Detect Behavior Test

� Test Lukaszewski theory:

– “CCA Preamble Detect: Fact vs. Fiction”

� Sept. 27th, 2015

� Chuck Lukaszewski

� Conduct empirical testing using lab setup

suggested in Chuck’s message

� Post initial results to email group

Objectives

Comments

� This shows the preliminary results of tests

conducted on Oct. 19, 2015 at personal

residence.

� Further tests at a second location are

planned.

Following are the specifications for the Access Point equipment used during this set of tests.

AP51 is a Cisco 1142 (2x3) dual-band 802.11n capable access point.– Autonomous

– Max Rate – 300 Mbps

– ESSID: AP51_Silver

– BSSID: 10:8C:CF:EA:87:70

AP52 is a Cisco 1142 (2x3) dual-band 802.11n capable access point.– Autonomous

– Max Rate – 300 Mbps

– ESSID: AP52_Silver

– BSSID: 10:8C:CF:EA:8D:50

http://www.cisco.com/c/en/us/products/collateral/wireless/aironet-1130-ag-series/datasheet_c78-502793.html

Section 2 - Identifying WiFi Problems 4

802.11ac – VHT Extended ChannelsAP STA Equipment

These are the specifications for the Client STA equipment used during this set of tests.

Wireless Client STA1 - 2013 Apple MacBook Pro Retina 802.11ac 3x3

– Associated to AP52

– Open System/No Encryption

– OS X Yosemite v10.10.1

– Broadcom BCM43xx A/G/N/Ac dual-band (3x3)

– Max Rate - 1300 Mbps

Wireless Client STA2 – AlienWare M17x10

– Associated to AP52

– Open System/No Encryption

– Windows 7 Ultimate / SP1 / 64 bit

– Intel Centrino Ultimate-N 6300 A/G/N dual-band (3x3)

– Max Rate – 450 Mbps

Wired iPerf Server STA3 – Fluke OptiView XG v13.0.0

– Directly connected to 1 Gbps Ethernet backbone

– Windows 7 Professional / SP1 / 64 bit

– Intel Core Duo CPU

– Max Rate – 1 Gbps

Monitor Station STA4 – Lenovo X220 Tablet PC

– AirMagnet Wi-Fi Analyzer v10.7.1 (Bld 35396)

– Windows 7 Professional / SP1 / 64 bit

– Intel Core i7 CPU

– Capture adapter: Proxim 8494-US (Orinoco 802.11 a/b/g/n)

Section 2 - Identifying WiFi Problems 5

802.11ac – VHT Extended ChannelsClient STA Equipment

These are the setup specifications used during this set of tests.

Testing Suite– jPerf (iPerf) server mode was used on a wired STA3 (Optiview XG)

– jPerf (iPerf) client mode was used at each Client STA

– AirMagnet Wi-Fi Analyzer was used on STA4 for side-by-side monitoring

Client STA1– Associated to AP1_Silver on 2.4 GHz, Ch 11, RSSI -89 (avg)

Client STA2– Associated to AP2_Silver on 2.4 GHz, Ch 11, RSSI -89 (avg)

RX Antenna Delta – Distance between Monitor STA and Clients– STA4 to STA1 ~5ʎ (24 in.)

– STA4 to STA2 ~5ʎ (24 in.)

Section 2 - Identifying WiFi Problems 6

802.11ac – VHT Extended ChannelsSetup

Begin First Test Procedure

� Connect and test throughput between

AP51 and STA1 only

� Connect and test throughput between

AP52 and STA2 only

STA4 View of AP51

STA1 Only Test Results

Initial Results: Client STA1 Only

� Wireless Client STA1 associated to

AP51_Silver on 2.4 GHz channel 11

– 60 second iPerf test run

– -89 dBm RSSI measured at STA4

– 87 Mbps nominal PHY rate to STA1

– 21.1 Mbps average iPerf throughput rate

(unidirectional)

STA4 View of AP52

STA2 Only Test Results

Initial Results: Client STA2 Only

� Wireless Client STA2 associated to

AP52_Silver on 2.4 GHz channel 11

– 60 second iPerf test run

– -87 dBm RSSI measured at STA4

– 39 Mbps nominal PHY rate to STA2

– 13.9 Mbps average iPerf Throughput Rate

(unidirectional)

Begin Second Test Procedure

� Connect and test throughput between

AP51/STA1 concurrent with AP52/STA2

� RSSI of concurrent devices on same

channel < -82 dBm

STA1 and STA2 Concurrent: STA4 View of AP51

STA1 and STA2 Concurrent: - STA2 begins test at 60 secs. -

STA1 and STA2 Concurrent: - STA1 test average at 300 secs. -

Initial Results: STA1 and STA2 Concurrent

� Wireless Client STA1 associated to

AP51_Silver on 2.4 GHz channel 11

– 300 second iPerf test run

– -86 dBm RSSI measured at STA4

– First 60 seconds, 14-15 Mbps average iPerf

Throughput Rate (unidirectional)

– At 61 seconds drops to 1-4 Mbps as STA2

begins testing

– Displays moderate to high jitter

– STA1 final average 5.57 Mbps

STA1 and STA2 Concurrent: STA4 View of AP52

STA1 and STA2 Concurrent: - STA2 begins test — STA1 already active. -

STA1 and STA2 Concurrent: - STA2 testing as STA2 ends -

STA1 and STA2 Concurrent: - STA2 throughput after STA1 ends. -

STA1 and STA2 Concurrent: - STA2 test average at 300 secs. -

Initial Results: STA1 and STA2 Concurrent

� Wireless Client STA2 associated to AP52_Silver

on 2.4 GHz channel 11

– 300 second iPerf test run

– -87 dBm RSSI measured at STA4

– First 240 seconds, 2-3 Mbps average iPerf

Throughput Rate (unidirectional)

– Displays moderate to high jitter

– At 243 seconds speed jumps up as STA1 completes

testing

– STA2 throughput speed 20 – 25 Mbps at 299 seconds

– STA2 final average 6.6 Mbps

Chuck Lukaszewski wrote:

“I would love to be wrong about this, but…”

� At this time, these results cannot dispute Chuck’s suggestion.

� However, additional tests will be performed using a different

location, different vendor equipment, 802.11ac capable equipment,

and 5 GHz channels.

� I will also attempt to use an even lower RSSI, somewhere closer to -

90 dBm

� I would like to know if anyone else has attempted these tests and

what their observations were.– Rick

– Mobile – 303-246-4257

Initial Determination