WALAA - WFA Licensed Assisted Access

Start: 01 April 2015
End: 30 June 2015
Funding: Industry
Status: Due
Division: Communication Networks
Department: Mobile Networks (MONET)
Web:  https://www.nsnam.org/wiki/LAA-WiFi-Coexistence

ns-3 is well-known for providing high fidelity, packet-level models of Wi-Fi and LTE , but simulation studies to date 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 the 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 is being conducted by CTTC and the University of Washington.

The project up to date has been organized in two phases:

In phase 1 we took care of extending ns3 modules with the necessary functionalities 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






  • University of Washington
  • Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)