In this paper, we present the Intelligent Hybrid MAC (IH-MAC), a novel low power with quality of service guaranteed medium access control protocol for wireless sensor networks (WSNs). The IH-MAC achieves high energy efficiency under wide range of traffic load. It ensures shorter latency to critical and delay-sensitive packets. The IH-MAC protocol achieves high channel utilization during high traffic load without compromising energy efficiency. The IH-MAC does it by using the strength of CSMA and TDMA approach with intelligence. The novel idea behind the IH-MAC is that it uses both the broadcast scheduling and link scheduling. Depending on the network loads, the IH-MAC protocol dynamically switches from broadcast scheduling to link scheduling and vice versa in order to achieve better efficiency. The scheduling is done in the IH-MAC with a novel decentralized approach where the nodes locally use the clock arithmetic to find the time slot, allocated for it. Furthermore, the IH-MAC uses Request-To-Send, Clear-To-send handshakes with methods for adapting the transmit power to the minimum level necessary to reach the intended neighbor. Thus, the IH-MAC reduces energy consumption by suitably varying the transmit power. The IH-MAC also uses the concept of parallel transmission that further reduces delay. The analytical and simulation results corroborate the theoretical idea, and show the efficiency of our proposed protocol.

An Intelligent Hybrid MAC With Traffic-Differentiation-Based QoS for Wireless Sensor Networks

Power management in SMAC-based energy-harvesting wireless sensor networks using queuing analysis

Duty-cycling allows obtaining significant energy saving compared to full duty cycle (sleepless) random access MAC protocols. However, it may result in significant latency. In slotted duty-cycled medium access control (MAC) protocols, sensor nodes periodically and synchronously alternate their operations between active and sleep modes. The sleep mode allows a sensor node to completely turn off its radio and save energy. In order to transmit data from one node to another, both nodes must be in active mode. The synchronous feature makes the protocols more appropriate for delay-sensitive applications compared to asynchronous protocols. The latter involve additional delay for the sender to meet the receiver's active period, which is eliminated with synchronous approach where nodes sleep and wake up all together. Despite the possible increase of contention by grouping active periods, the delay due to packets retransmissions after collisions is less significant compared to the waiting time of asynchronous protocols. Furthermore, contention-based feature makes the protocol conceptually distributed and more dynamic compared to TDMA-based. This manuscript deals with timeliness issues of slotted contention-based WSN MAC protocols. It provides a comprehensive review and taxonomy of state-of-the-art synchronous MAC protocols. The performance objective considered in the proposed taxonomy is the latency, in the context of energy-limited WSN, where energy is considered as a constraint for the MAC protocol that yields the need of duty-cycling the radio. The main contribution is to study and classify these protocols from the delay efficiency perspective. The protocols are divided into two main categories: static schedule and adaptive schedule. Adaptive schedule are split up into four subclasses: adaptive grouped schedule, adaptive repeated schedule, staggered schedule, and reservation schedule. Several state-of-the-art protocols are described following the proposed classification, with comprehensive discussions and comparisons with respect to their latency.

Synchronous Contention-Based MAC Protocols for Delay-Sensitive Wireless Sensor Networks: a Review and Taxonomy

Review: Synchronous contention-based MAC protocols for delay-sensitive wireless sensor networks: A review and taxonomy

This paper proposes latency and energy efficient flexible TDMA (LEFT), a medium access control (MAC) combined with routing protocol for data gathering from number of source nodes to a master station (MS) in a wireless sensor network (WSN). TDMA provides fairness, collision-free communication and reduces idle listening, which saves network energy. Data latency is reduced by allocating same transmission slots to nodes falling out of interference range of each other. Unlike a conventional TDMA, LEFT provides flexibility through slot seizing, wherein a non-holder of a slot can use slot when holder does not have data to send. This increases channel utilization and adaption to dynamic traffic patterns of WSN applications. Further, a node on a multi-hop path towards MS decides to participate in routing based on (i) its location with respect to MS, to forward data in correct direction, (ii) its current status of residual energy, to uniformly distribute energy across network, (iii) its transit traffic load, to prevent local congestion, (iv) its communication link quality, to guarantee reliable data delivery. This decision requires simple comparisons against thresholds, and thus is very simple to implement on energy, storage and computationally constrained nodes. LEFT also encompasses techniques to cater to link and node breakdowns. Experimental analysis of LEFT; Advertisement-based TDMA; Data gathering MAC; Energy Efficient Fast Forwarding and Cross layer MAC protocols using TI’s EZ430-RF2500T nodes shows that LEFT is 65% more energy efficient compared to Cross layer MAC. Data latency of LEFT is 27 % less, delivery ratio is 17 % more and goodput is 11 % more compared to Cross layer MAC.

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LEFT: A Latency and Energy Efficient Flexible TDMA Protocol for Wireless Sensor Networks

In this work, we carried out the performance analysis of Optimized Medium Access Control (MAC) Protocol for the wireless sensor network. This MAC protocol solves the energy inefficiency taking nodes latency into consideration based on the network traffic. It achieves high-energy efficiency under wide range of traffic loads and is able to adjust itself to improve the delay performance when the network traffic load is high.

Performance Analysis of Optimized Medium Access Control for Wireless Sensor Network

Medium access control for wireless sensor networks has been a very active research area in the recent years. The traditional wireless medium access control protocol such as IEEE 802.11 is not suitable for the sensor network application because these are battery powered. The recharging of these sensor nodes is expensive and also not possible. The most of the literature in the medium access for the sensor network focuses on the energy efficiency. The proposed MAC protocol solves the energy inefficiency caused by idle listening, control packet overhead and overhearing taking nodes latency into consideration based on the network traffic. Simulation experiments have been performed to demonstrate the effectiveness of the proposed approach. The validation of the simulation results of the proposed MAC has been done by comparing it with the analytical model. This protocol has been simulated in Network Simulator ns‐2.

N. Malaviya

Papers

Performance Analysis of Optimized Medium Access Control for Wireless Sensor Network

Traffic Adaptive Energy Efficient and Low Latency Medium Access Control for Wireless Sensor Networks