Scheduler for the Multi User MAC Framework for IEEE 802.11ax
Scheduler for the Multi User MAC Framework for IEEE 802.11ax
Outline: In this project, you will work on developing a MAC layer scheduler for the MU MAC layer framework of the upcoming IEEE 802.11ax standard using a network simulator.
Instructor: Prof. Tuna Tuğcu, (assistance by Dr. M. Şükrü Kuran, AirTies Wireless Networks)
Prerequisites: Computer Networks
The upcoming WiFi standard, IEEE 802.11ax, focuses on increasing the throughput in highly congested areas where the increased number of STA’s (i.e., user devices) cause significant throughput loses due to the random access nature of the IEEE 802.11’s MAC layer. To alleviate this performance loss, IEEE 802.11ax will introduce several key features such as OFDMA, uplink MU-MIMO, and a Multi-user MAC framework (MU MAC) in which instead of the classical random-access based DCF mechanism, the AP will have the option of strictly coordinating all transmissions within the BSS.
In this MU MAC framework, based on various parameter values of each STA (e.g., RSSI level, WiFi capabilities, buffer/queue status,…), the AP will orchestrate which device (i.e., AP or STA) to send their MAC frames in which OFDMA tones, antennas, time slot by means of a MAC layer scheduler. The AP will be able to ask for all of these information from the connected STA’s using various frame formats (e.g., the new Buffer Status Report – BSR frame) and build its schedule upon these values [1]. Similar to previous IEEE standards, the MAC layer scheduler to be deployed in the AP’s will be left unstandardized in IEEE 802.11ax and each vendor will have the option of developing their own propriety MAC layer scheduler.
In this project, you will be asked to develop a MAC layer scheduler for the MU MAC framework of the upcoming IEEE 802.11ax standard. Your scheduler will take all of the performance affecting parameter values such as RSSI level, WiFi capabilities, buffer/queue status, QoS level, etc… into consideration and periodically build up a schedule in order to attain a higher MAC layer throughput and reduced MAC layer delay. The scheduler should also has the option of switching between the classical random-access based DCF mechanism and the new MU MAC framework based on the number of connected STA’s.
During the project, you should be learning about the effects and importance of the aforementioned performance parameters and device a MAC layer scheduler. Next, you should present the performance of your devised MAC layer scheduler in different topologies and traffic loads by means of a simulation by comparing its performances with the performance of a classical sole DCF-based system. As for the simulator, you should be using the NS3 simulator [2]. There is an “802.11ax add-on” to the NS3’s WiFi framework however, currently it does not include the MAC layer mechanisms that are needed for the MU MAC layer framework [3].
References:
- Qu et al., “Survey and Performance Evaluation of the Upcoming Next Generation WLAN Standard - IEEE 802.11ax,” arxiv.org, https://arxiv.org/abs/1806.05908, 2018.
- “NS3 Simulator”, https://www.nsnam.org .
- “NS3 Simulator of 802.11ax,” https://github.com/cisco/ns3-802.11ax-simulator