submission doc.: ieee 802.19-15/0055r3 july 2015 ben lampert, octoscopeslide 1 unlicensed lte/wifi...
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Submission
doc.: IEEE 802.19-15/0055r3July 2015
Ben Lampert, octoScopeSlide 1
Unlicensed LTE/WiFi Coexistence TestbedDate: 2015-07-06
Name Affiliations Address Phone email Ben Lampert octoScope 9712182444 Ben.Lampert@octoScope.
com
Akhila Nandgopal
octoScope 17745786774 Akhila.Nandgopal@octoScope.com
Authors:
Submission
doc.: IEEE 802.19-15/0055r3July 2015
Ben Lampert, octoScopeSlide 2
Abstract
Propose an Unlicensed-LTE/Wi-Fi testbed for coexistence characterization.
Submission
doc.: IEEE 802.19-15/0055r3
Ben Lampert, octoScope
Common Testbed Motivation• Everyone benefits from testing real devices and
applications that would be difficult to recreate in a simulation
• Wi-Fi community will benefit from “hands on” experience with Unlicensed LTE to evaluate their applications and devices
• 3GPP will benefit by alleviating concerns about coexistence mechanisms and using data to inform LTE-LAA decisions
• A neutral test platform can provide fair sharing data for both Wi-Fi and Unlicensed LTE to help inform decisions from both groups
Slide 3
July 2015
Submission
doc.: IEEE 802.19-15/0055r3
Ben Lampert, octoScope
LTE-LAA Benefits from Participating in Testing
• Testbed will allow for any early LTE-LAA development units to be tested (ie, rack mounted)
• Can use existing Wi-Fi/LTE-U devices to help drive LTE-LAA decisions based on real interactions.• Best Coexistence Mechanisms
• Energy detection thresholds
• Real device traffic patterns and application behavior
• Channel selection algorithms
• Good LTE-U Coexistence data already taken [1], input from Wi-Fi community can only help inform decisions
Slide 4
July 2015
Submission
doc.: IEEE 802.19-15/0055r3
Ben Lampert, octoScope
Possible Test Scenarios
• Testbed to define and validate fairness• Wi-Fi/LTE, Wi-Fi/Wi-Fi, LTE/LTE
• Fairness criteria including• VoIP, Packet Jitter, Airtime, Throughput, etc
• Neutral Testbed for vendors (LTE/Wi-Fi) to test particular scenarios• Hidden Nodes
• High Density Environments
• Operation in different CCA detection thresholds
• Application/vendor specific tests
• Adjacent/Co-Channel Interference
Slide 5
July 2015
Submission
doc.: IEEE 802.19-15/0055r3July 2015
Ben Lampert, octoScopeSlide 6
Intro to Unlicensed-LTE Testbed
• Goal was to design a RF environment that was flexible for testing variety of Unlicensed LTE/LTE-LAA/LTE-U/Wi-Fi scenarios.
• Based on our understanding the requirements for a wireless contention test bed are:• High Isolation from external devices
• Good control over power levels across devices
• Multipath Environment to test MIMO STA’s
• Ability to test real applications (VoIP, Video streaming, file transfer, etc)
• Flexibility to test high channel load environments
• Repeatability and in a lab environment
• Focused on simple scenario:• Wi-Fi AP-STA baseline with added Wi-Fi or LTE eNB traffic
Submission
doc.: IEEE 802.19-15/0055r3
Ben Lampert, octoScope
Coexistence Testbed with multipath
Slide 7
July 2015
OTA
Wi-Fi STAsEthe
rnet
, HDM
I, US
B Po
rts
802.11 AP
Ethernet
Ethernet
Wi-Fi sniffer
Multi-Path Emulation
LTE eNB / Wi-Fi AP
Wi-Fi
LTE
8
LTE UEs
LTE monitor
8
Attenuator
Attenuator
Goals:-OTA (Over the air) Coexistence testing-Multi Path Emulation (Can be bypassed)-Wi-Fi traffic to clients benchmarked before and after LTE introduced-Wi-Fi sniffer helps diagnose channel loading/packet timing-Can be used to test real life applications (video streaming, VoIP, etc).-Attenuation helps tune power received on STA/UE.-Can test two 4x4 Wi-Fi AP’s or a 4x4 Wi-Fi AP with a 2x2 LTE device.
Submission
doc.: IEEE 802.19-15/0055r3
Ben Lampert, octoScope
Coexistence Testbed w/o multipath
Slide 8
July 2015
OTA
Wi-Fi STAsEthe
rnet
, HDM
I, US
B Po
rts
802.11 AP
Ethernet
Ethernet
Wi-Fi sniffer
LTE eNB
Wi-Fi
LTE
Attenuator
6-8
LTE UEs
LTE monitor
4
2-4
Goals:-Similar to multipath testbed-AP and eNB couple OTA in top box via antennas.
Submission
doc.: IEEE 802.19-15/0055r3
Ben Lampert, octoScope
Hidden Node Scenario• One possible test scenario is characterizing how
Unlicensed-LTE and Wi-Fi handle hidden nodes
• When group 1,3 cannot directly observe each other or observe below ED levels how will the detection mechanisms work?
Slide 9
July 2015
AP1/enB1 AP2/enB2 AP3/enB3
Hidden Node problem:Groups 1,2 and 2,3 can observe each other. But groups 1,3 cannot (outside of the Rx sensitivity)
Clients1 Clients3Clients2
Submission
doc.: IEEE 802.19-15/0055r3
Ben Lampert, octoScope
Multiple Nodes/Hidden Node Testbed
Slide 10
July 2015
Wi-Fi
LTE
Wi-Fi/LTE Clients
Attenuator Attenuator
Wi-Fi/LTE Clients
Wi-Fi
LTE
AP/eNB Box 1 AP/eNB Box 2
Client Box 1 Client Box 2
Attenuator
AP/eNB Box 3
Client Box 3
Wi-Fi
LTE
Wi-Fi/LTE Clients
Submission
doc.: IEEE 802.19-15/0055r3
Ben Lampert, octoScope
Hidden Node Configuration
Slide 11
July 2015
5Ghz Path LossAttenuator Client-Client 6Attenuator AP-Client 6Cables 3OTA Loss 40Tx Power +24dBmRx Threshold >-100dBm
• Clients and AP/eNB in Box 2 see both C1/AP1 and C3/AP3• Devices in 1 and 3 cannot observed each other (outside of
the Rx Sensitivity)• Link between 1/3 can be added depending on scenario.
Est. Rx Power (dBm) C1 Rx C2 Rx C3 Rx AP1 Rx AP2 Rx AP3 RxC1 Tx - -65 -111 -25 -71 -117C2 Tx -65 - -65 -71 -25 -71C3 Tx -111 -65 - -117 -71 -25
AP1 Tx -25 -71 -117 - -77 -123AP2 Tx -71 -25 -71 -77 - -77AP3 Tx -117 -71 -25 -123 -77 -
Submission
doc.: IEEE 802.19-15/0055r3
Ben Lampert, octoScope
Extra Slides
Slide 12
July 2015
Submission
doc.: IEEE 802.19-15/0055r3
Ben Lampert, octoScope
Rack Mount Testing
Slide 13
July 2015
OTA
Wi-Fi STAsEthe
rnet
, HDM
I, US
B Po
rts
802.11 AP
Ethernet
Ethernet
Wi-Fi sniffer
Option 1: Rack inside chamberLTE eNB (Rack mounted)
Wi-Fi
Attenuator
6
LTE UEs
LTE monitor
4
2Option 2: Rack outside of
chamberLTE eNB (Rack mounted)
2
• Ideally would like to put in the chamber to maximize isolation, but this may not be an option.
• Rackmount RF shielding may also be poor, so may consider putting enB in it’s own box to reduce leakage.
Submission
doc.: IEEE 802.19-15/0055r3
Ben Lampert, octoScope
Multiple Small Cell Testbed
Slide 14
July 2015
LTE-U Indoor Simulation Scenarios (SI5-8)
-Based on test scenarios provided by 3GPP (See 2)
-Chaining chambers expands wireless loading/environment
-Multiple AP’s, Small Cells operating co-channel
Length = 120 m
Wid
th =
50
m
15 m
15 m
Operator 1 Small CellOperator 2 Small CellPrivate WiFi AP
1 2 3
1 2 3
Links between nodes control interactions
n
n
Submission
doc.: IEEE 802.19-15/0055r3
Ben Lampert, octoScope
Possible Multiple Small Cell/Enterprise loading configuration
Slide 15
July 2015
RF daisy-chain coupling to emulate space among AP/eNB pairs
Submission
doc.: IEEE 802.19-15/0055r3July 2015
Ben Lampert, octoScopeSlide 16
References
[1] LTE-U Technology and Coexistence, LTE-U Forum May 28th, 2015
http://www.lteuforum.org/uploads/3/5/6/8/3568127/lte-u_coexistence_mechansim_qualcomm_may_28_2015.pdf
[2] LTE-LAA 3GPP Document 36.889-011
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