Biased contribution index: a new faster convergent index to maintain the fairness in peer-to-peer networks

The free-riding and large difference between upload and download amount of resources is a fundamental problem in a peer-to-peer network. An incentive mechanism, which can be implemented in a distributed fashion, can solve this problem. Global contribution (GC) approach is one such mechanism, but its speed of convergence is slow. This letter proposes a new index named biased contribution index (BCI). It is proved that BCI always converges at a certain value. Simulation results show that it converges faster than the GC.