Sub-channels Access Scheduling and Rate Adaptation for Very High Throughput WLANs

PhD Qualifying Examination


Title: "Sub-channels Access Scheduling and Rate Adaptation for Very High Throughput 
WLANs"

by

Mr. Arafet BEN MAKHLOUF


Abstract:

The transition from wired to wireless networks have opened up new horizons for 
research. The IEEE 802.11 Wireless Local Area Networks (WLANs) have become 
increasingly popular due to the recent availability of affordable devices 
providing multiple and high rate capabilities. Optimizing the performance of 
wireless networks for emerging network applications is an important and a 
highly challenging issue.

In the next generation WLAN standards like IEEE 802.11ac and 802.11ad, new PHY 
and MAC layer enhancements have been introduced. These improvements have given 
birth to wide bandwidth channels and very high transmission rates (>1Gbps) to 
keep up with current and upcoming multimedia applications. However, the major 
reason for the inefficiency of different WLANs is that the current MAC layer 
randomly allocates the entire channel to only one user as a single resource. 
Thus, we argue that a better way to improve WLAN performance is to effectively 
reduce the channel width and create different sized channels (sub-channels), 
and serve several users simultaneously. In Addition, the Quality of Service 
(QoS) is very important for the Very High Throughput WLANs. Scheduling access 
for flows in a non-interfering manner to avoid packet loss and adapt rates to 
changing channel conditions are important aspects of QoS in wireless networks. 
The goal of the rate adaptation scheme is to select the best set of 
transmission parameters for a given user considering its channel conditions. 
Similar to that goal, sub-channels scheduling access can be seen as selecting 
the best set of users to allocate subcarriers according to their channel state 
information.

Data traffic has diverse characteristics and thus different transmission 
requirements. In particular, an advanced version of Multimedia-MAC should exist 
to dynamically adjust the bandwidth allocation according to the instant status 
of traffic load so that both network channel utilization and QoS for different 
types of traffic streams will be enhanced dramatically. In this survey, our 
plan is to design a dynamic sub-channel assignment method based on traffic 
priority, in order to maximize throughput. Also, we propose to profit from the 
sub-channels access approach and adapt the rate separately for each block of 
subcarriers according to the channel variations, for more improvement. Thus, an 
efficient access scheduling and rate control schemes can effectively guarantee 
QoS and maximize the throughput. Our future objective is to develop an 
efficient packet scheduling model and rate adaptation scheme, and test their 
performances with real hardware devices in the present and next generation of 
WLANs, by applying the simultaneous multi-user access approach.


Date:                   Friday, 6 January 2012

Time:                   10:00am - 12:00noon

Venue:                  Room 3494
                         lifts 25/26

Committee Members:	Prof. Mounir Hamdi (Supervisor)
 			Dr. Jogesh Muppala (Supervisor)
                         Dr. Gary Chan (Chairperson)
 			Dr. Brahim Bensaou
 			Dr. Lei Chen


**** ALL are Welcome ****