Priority Scheme for Mobile Nodes in P2P Bit-Torrent Based Networks

Peer-to-Peer (P2P) networks are distributed systems where no central authority rules the behavior of the individual peers. Given the pervasive use of wireless systems, based on the IEEE 802.11 and LTE standards, it is expected that an important amount of the P2P traffic will be cursed on such networks. In a wireless environment, users typically experience different channel conditions. This has a major impact on the performance of the system as it is perceived by users in different coverage zones. Additionally, users have a certain degree of mobility which can improve or degrade the quality of the received signal. In this work, a wireless P2P network with different coverage zones is studied. As it is shown, the system´s performance is greatly affected by the number of nodes in each zone. Additionally, the movement of the nodes is also considered. Building on this, a priority scheme that assigns the available bandwidth to users in the zones with better coverage is presented. The rationale behind this is that by allowing the peers to download the file before the rest of the peers, increases the total bandwidth in the system. Two different scenarios are considered for the performance evaluation: WLAN and Cellular. The proposed priority scheme is analyzed using a Continuous Time Markov Chain.