Batch and Sequential Bayesian Estimators of the Number of Active Terminals in an IEEE 802.11 Network

Tom Vercauteren, Alberto Lopez Toledo

Following Toledo's trail, I read this paper in which the authors describe how to estimate the number of active stations in a IEEE 802.11 network. Bayesian algorithms are used to construct a number of off-line and on-line estimators with different degrees of complexity and accuraci.

Event thought I could not grasp the mathematical core, the references will be quite useful, since I am also working on optimizing the network performance for a variable number of stations. Further, the description of the simulations can be used as a reference for future works.

A Robust Kolmogorov-Smirnov Detector for Misbehavior in IEEE 802.11 DCF

Alberto Lopez Toledo and Xiaodong Wang

The proposal is to measure the number of empty slots between transmissions of a given station. Then use the K-S technique to estimate the cdf and compare to the expected cdf. When the actual cdf clearly differs from the expected cdf, it is inferred that the node is missbehaving.

Stability and Performance of the R-ALOHA Packet Broadcast System

SHUJI TASAKA

R-Aloha differs from Aloha in the fact that a stations implicitly obtains a reservation for the channel whenever it successfully transmits a packet. The slots are grouped in frames, and the station obtains a reservation in each frame. This idea is interesting because in steady state operation, collisions are avoided and the system operates as in tdma.

The mathematical tool used in the analysis is Equilibrium Point Analysis (EPA)

Enhancement of IEEE 802.11 Distributed Coordination Function with Exponential Increase Exponential Decrease Backoff Algorithm

Nah-Oak Song, Byung-Jae Kwak, Jabin Song, Leonard E. Miller

Short paper that proposes an alternative to the doubling of the contention window and evaluates the new proposal using simulation

Stability of Binary Exponential Backoff

JONATHAN GOODMAN et al

Hard-core mathematical stuff. It comes at no surprise since the paper is written in a mathematical institute. Maybe the references are of some use.

Using Incompletely Cooperative Game Theory in Wireless Mesh Networks

Liqiang Zhao and Jie Zhang, University of Bedfordshire
Hailin Zhang, Xidian University

The inclusion of game theory in the title might sound scary, but the paper is not complicated. It inspired me the idea of looking for more efficient backoff mechanisms.

new backoff scheme

The current backoff scheme is independent of the number of contending stations. The result is that is desirable to adjust CWmin to its optimum value. I've been thinking about a backoff algorithm that reacts and adapts to the number of active contending stations.

Solutions to Performance Problems in VoIP Over a 802.11 Wireless LAN

Wei Wang, Soung Chang Liew, and Victor O. K. Li
This paper already highlight the main impairments in VoWLAN: Protocol overhead and uplink/downlink unfairness.
Their solution (M-M) consists on multiplexing-multicasting the packets for download. These multicasted packets require strict prioritization to avoid collision.

The main drawback I can see is how could be this combined with level-2 security (WPA) so widespread this days.

The authors also analyze the impact their solution has on delay and the impact of elastic flows on the number of VoIP Streams.

A New Access Control Solution for a Multi-Provider Wireless Environment

ARTUR HECKER et al.

Maybe it is because monday morning, but could not get the point. It was something about 4G and a smart card similar to a sim.

Verification of Common 802.11 MAC Model Assumptions

David Malone and Ian Dangerfield and Doug Leith

Very interesting paper that compare values obtained from the models with those obtained from testbeds. Again, it is something that I was thinking to be necessary. Additionally there are many references I must read.

Inter-Vehicle Communications

Marc Torrent Moreno

This thesis studies IVC based on 802.11p, a variant of 802.11 for vanet. After describing the general characteristics of this kind of networks and introducing a modification of ns-2 specifically for vanets, proposes two new protocols. One for power control that avoids channel congestion, the other for fast propagation of emergency information. The two protocols are evaluated using the simulator.