A robustness analysis of a practical contention resolution algorithm under misbehaved users in wireless communication systems

This paper presents an analysis of a practical contention resolution algorithm referred to as UNI for medium access control protocols in high bit-rate wireless communication systems with two groups of users, i.e. normal and misbehaved users. The objective is to examine the robustness of the UNI algorithm when some users (misbehaved) do not conform to the agreed rules by accessing more reservation slots than they are permitted. Mathematical analysis is derived and applied to determine the average success rate of each group of users as well as the overall system performance. Computer simulations are also conducted to confirm and validate the mathematical model. Numerical results on various traffic conditions indicate that misbehaved user could potentially gain some throughput advantages when the number of slots available is relatively much higher than the number of overall users; this is achieved by carefully selecting proper number of tokens. However, when the number of overall users becomes greater than the number of slots the reversed effect is observed