Difference between revisions of "LAA-WiFi-Coexistence"

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The implementation has evolved since the November 3GPP RAN1 meeting and more current results are documented in the links below.
 
The implementation has evolved since the November 3GPP RAN1 meeting and more current results are documented in the links below.
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A recent presentation (May 2016) is available [http://www.nsnam.org/~tomh/ns-3-lbt-presentations/LAA-Wi-Fi-Coexistence-May2016.pdf here].
  
 
== Getting started ==
 
== Getting started ==

Revision as of 22:55, 4 June 2016

Main Page - Current Development - Developer FAQ - Tools - Related Projects - Project Ideas - Summer Projects

Installation - Troubleshooting - User FAQ - HOWTOs - Samples - Models - Education - Contributed Code - Papers

Overview

ns-3 is an integrated system simulator with full-stack simulation capabilities, and is known for providing high fidelity models of Wi-Fi and LTE. However, simulation studies to date (using released versions of ns-3) have not tried to combine the technologies on the same channel. In industry, 3GPP is defining standards for using LTE in unlicensed spectrum. The term License-Assisted Access (LAA) is frequently used to refer to these extensions, and refers to the fact that the use of unlicensed spectrum is complementary to the use of licensed spectrum for LTE, with the unlicensed spectrum providing complementary or secondary carriers that can be aggregated with carriers on licensed frequencies.

This page describes a project sponsored by Wi-Fi Alliance to improve ns-3 models to facilitate studies about the coexistence of Wi-Fi and unlicensed variants of LTE on the same channel. The project was conducted by CTTC and the University of Washington in 2015 and is currently seeking funding to continue.

Design

Phase 1

This phase has produced a new Wi-Fi Spectrum-based physical layer, enabling Wi-Fi devices and LTE devices to coexist on the same ns-3 channel. Beyond this enabling capability, several enhancements to the ns-3 models have been made:

  • Enhancements to Wi-Fi clear-channel access (CCA) and frame synchronization models
  • A Wi-Fi roaming model for AP selection based on received signal strength
  • LTE interference model enhancements
  • New indoor and outdoor propagation models
  • Wi-Fi MIMO and interference models for fading model D
  • Duty-cycled LTE transmission model
  • Scenarios corresponding to the indoor and outdoor scenarios defined in 3GPP TR36.889
  • A framework for executing simulation campaigns and quickly plotting the results

Phase 2

Phase 2 was focused on developing models related to the standardization process for Release 13 which concluded in December 2015. In particular, a "Listen-Before-Talk" (LBT) mode was developed for LTE, and scenarios were constructed to evaluate technical topics such as the sensitivity on performance on the Energy Detection threshold used for the LBT CCA mechanism.

Software

The software is available in a repository at ns-3's main code server, http://code.nsnam.org:

  • The phase 1 code is available with Mercurial, can be browsed on the web, or by download in a zip or tar.bz2 format.
  • The phase 2 code (updated to ns-3.25 release as of this May 2016 writing) is available with Mercurial, can be browsed on the web, or by download in a zip or tar.bz2 format.

The software will eventually be migrated to ns-3 releases, but as of the latest ns-3.25 release, none of the above extensions are available in the main release.

The extensions reside in four main directories:

  • Scripts, tests, and documentation to construct simulations involving these new models are in 'src/laa-wifi-coexistence'
  • Extensions to LTE to enable unlicensed variants are in 'src/lte'
  • Extensions to the Wi-Fi module to enable the SpectrumWifiPhy and new error models are in 'src/wifi'
  • Propagation model extensions are in 'src/propagation'

Reports

A contribution to the November 3GPP RAN1 meeting (R1-156621) has been generated. Steps to reproduce the experiments in the contribution are documented in the file 'src/laa-wifi-coexistence/experiments/README.txt' in the phase 2 repository.

The implementation has evolved since the November 3GPP RAN1 meeting and more current results are documented in the links below.

A recent presentation (May 2016) is available here.

Getting started

All figures and data in the 3GPP RAN1 meeting contribution can be generated by following the steps in the above ns-3-lbt Phase 2 archive by consulting the README.txt in the software directory under 'src/laa-wifi-coexistence/experiments/README.txt'.

Additional documentation (in progress) is available at the following URLs:

Contacts

Contact Tom Henderson (tomhend@u.washington.edu) for more information.