A Joint Routing and MAC Protocol for Transmission Delay Reduction in Many-to-One Communication Paradigm for Wireless Sensor Networks

We propose a joint routing and medium access control (MAC) protocol, named as JRAM, for reducing transmission delays in a many-to-one communication paradigm for wireless sensor networks (WSNs). Due to the wide variety of WSN applications, there is a need for protocol solutions optimized for specific application classes. JRAM is proposed for WSNs deployed for monitoring multiple events in the same geographic region which require prompt detection and response. In existing contention-based synchronous MAC protocols designed for this, a node gets only one chance to succeed in data transmission scheduling per cycle, and a sink can also only receive data packets from at most one node in a cycle. Therefore, end-to-end transmission delay (E2ETD) and packet delivery ratio (PDR) of these protocols drastically degrade with the increase in event occurrence rate (EOR). In contrast, JRAM proposes a novel approach to provide k (k > 1) chances to a node to succeed in data transmission scheduling in a cycle, and also allows a sink to receive data packets from k nodes in the same cycle. This is done, in JRAM, by partitioning the network nodes into k disjoint sets and then using a novel cycle structure. We evaluate JRAM through extensive NS-2.35 simulations and compare its performance with existing pipelined data collection (PDC), adaptive data collection (ADC), and CROPMAC protocols, for different types of traffic loads and traffic patterns. Results suggest that in case of high EOR, JRAM outperforms PDC, ADC and CROPMAC both in terms of the E2ETD and the PDR.