Implementation Of MAC Protocol Research Articles

Implementation of MAC protocol with enhanced security features in VANET

Vehicular Area Network (VANET) is essential to reduce road accidents and to efficiently control large numbers of vehicles on the highways. Methods of establishing secure connection between vehicular nodes present in a VANET is the first priority of researchers, numbers of protocols have being developed and implemented for the same. There is still a lot of scope for refinement in the currently implemented protocols. The most prominent issue is packet drop due to unsynchronised packet transmission, which results in delay and collision in the VANET. Apart from packet drop, authenticity of packets is also an important issue. This paper analyses security issues in VANET and proposes a secure MAC protocol. Four salient features of the proposed protocol are: (i) automatic size adjustment of contention window according to network capacity, (ii) channel allocation for each node based on TDMA and SDMA, (iii) priority assigning for each type of messages, and (iv) security checking for each packet using CRC.

Implementation of MAC protocol with enhanced security features in VANET

Implementation of MAC protocol with enhanced security features in VANET

Synchronized CSMA Contention: Model, Implementation, and Evaluation

A class of carrier sense multiple access (CSMA) protocols used in a broad range of wireless applications uses synchronized contention where nodes periodically contend at intervals of fixed duration. While several models exist for asynchronous CSMA contention used in protocols like IEEE 802.11 MAC, no model exists for synchronized CSMA contention that also incorporates realistic factors like clock drifts. In this paper, we introduce a model that quantifies the interplay of clock drifts with contention window size, control packet size, and carrier sense regulated by usage of guard time. Using a field programmable gate array (FPGA)-based MAC protocol implementation and controlled experiments on a wireless testbed, we evaluate the model predictions on the isolated and combined impact of these key performance factors to per-flow throughput and fairness properties in both single-hop and multihop networks. Our model and experimental evaluation reveal conditions on protocol parameters under which the throughput of certain flows can exponentially decrease; while at the same time, it enables solutions that can offset such problems in a predictable manner.