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