Low-power Medium Access Control Protocols Research Articles

Power Saving MAC Protocols for Wireless Body Area Networks (WBANs)

Two important criteria of wireless body area networks (WBANs) are low power consumption and delay. These criteria can be met by designing efficient medium access control (MAC) protocols. In this paper, two TDMA-based MAC protocols are proposed. The first protocol, TM–MAC makes use of only a main radio. The second proposed protocol, TWM–MAC makes use of a WUR alongside the main radio. The two proposed protocols are compared with different categories of standard MAC protocols and it is shown that they outperform the standard ones by improving the power consumption and delay. The TWM–MAC consumes 55% less power consumption than the Scheduled Channel Polling MAC (SCP–MAC) protocol for a high traffic scenario on the high-rate platform while the TM-MAC consumes 85% less power consumption than the SCP–MAC. For a low traffic scenario, the TWM–MAC performs 53.5% better than the SCP–MAC protocol and 77.5% better than the very low power MAC (VLPM) protocol on the high and low-rate platforms respectively. An improvement in delay was observed with the TWM–MAC protocol for high traffic situations. The TWM–MAC protocol surpasses the VLPM protocol by 81.1% in terms of latency for a high traffic scenario and 3.2% for a low traffic scenario.

Low-delay fair-reliability scheduling in multi-hop IEEE802.15.4e time synchronised channel hopping networks

IEEE802.15.4e is the latest generation of high-reliability, low-power medium access control protocols. As part of IEEE802.15.4e, time synchronised channel hopping (TSCH) provides support for multi-...

Energy-efficient MAC protocols for wireless sensor networks: a survey

Wireless sensor network (WSN) is a network of a large number of battery-powered tiny sensor nodes wirelessly connected together to facilitate a wide range of monitoring applications. As WSN nodes are energy-constrained microelectronic devices, the primary design objective of WSNs is to minimise energy consumption to prolong the network lifetime. To achieve this goal, a range of cross-layer techniques, particularly focusing on medium access control (MAC) sublayer, is proposed targeting different WSN applications. This paper aims to survey low-power WSN MAC protocols, proposed from 2000 to the present, emphasising some general aspects including the issues addressed, the solutions proposed, design principles, strengths, drawbacks and target applications. With this aim, we mainly classify the MAC protocols into three categories: contention-based protocols, time division multiple access (TDMA)-based protocols and hybrid protocols, where the first category is further subdivided into subclasses. The development trends and potential research challenges are also discussed.

A Dynamic Adaptation Mechanism for Traffic Conditions in Wireless Sensor Network

As overall network traffic pursue to expand, a lot of low-power medium access control protocols have been proposed to deal with burst traffic in wireless sensor network. Although most of them provide low throughput but do not well optimize the energy consumption. In this paper, we propose a new hybrid carrier sense multiple access with collision avoidance (CSMA/CA) and time division multiple access (TDMA) protocol that arranges nodes into two categories of priority according to their traffic rate and data transmission delay. Nodes that have continuous data should send its data during the contention free period, those one will be classified as low priority and its data will be scheduling using TDMA. Others nodes who have a random data should transmit it immediately during the contention access period (CAP) using a fuzzy logic algorithm, based on their queue length and implemented in the CSMA/CA algorithm. Therefore, the proposed scheme dynamically changes the CAP length to ensure that nodes can complete its transaction during the same super-frame. Simulation results are done using the network simulator tools (NS-2) and have improved good efficiency regarding the IEEE 802.15.4 standard. The mechanism has improved the energy consumption, minimised the packet loss probability, increased the throughput variation in the network and also minimised the average end to end delay.

Low-power neighbor discovery for mobility-aware wireless sensor networks

While more and more deployments of Wireless Sensor Networks (WSNs) are successful, very few are actually mobility-aware. Due to their intermittent connectivity, mobile nodes induce certain instabilities, and thus, require to transmit multiple data packets in a short period of time. The nature of mobile nodes can lead to a link quality deterioration or even more to link disconnection. This instability requires frequent link establishments between a mobile and a neighboring static node before initiating data packet transmissions. To do so, the need for an efficient Medium Access Control (MAC) protocol is extremely important and challenging. In this paper, we present MobiDisc, an advanced mobile-supporting scheme for low-power MAC protocols, which allows for efficient neighbor(hood) discovery and low-delay communication. Moreover, we propose a FAN (First Ack Next-hop) mode that accelerates transmissions. Both MobiDisc and MobiDisc-FAN come with a Fast Recovery Mechanism (FRM) that enables seamless handovers in the network. Our thorough performance evaluation, conducted on top of Contiki OS, shows that MobiDisc outperforms a number of state-of-the-art solutions (including MoX-MAC and ME-ContikiMAC), by terms of reducing both delay and energy consumption, while the reliability is kept over 98%.

Reliability comparison of transmit/receive diversity and error control coding in low‐power medium access control protocols

Low-power medium access control (MAC) protocols used for communication of energy constraint wireless embedded devices do not cope well with situations where transmission channels are highly erroneous. Existing MAC protocols discard corrupted messages which lead to costly retransmissions. To improve transmission performance, it is possible to include an error correction scheme and transmit/receive diversity. It is possible to add redundant information to transmitted packets in order to recover data from corrupted packets. It is also possible to make use of transmit/receive diversity via multiple antennas to improve error resiliency of transmissions. Both schemes may be used in conjunction to further improve the performance. In this study, the authors show how an error correction scheme and transmit/receive diversity can be integrated in low-power MAC protocols. Furthermore, the authors investigate the achievable performance gains of both methods. This is important as both methods have associated costs (processing requirements; additional antennas and power) and for a given communication situation it must be decided which methods should be employed. The authors’ results show that, in many practical situations, error control coding outperforms transmission diversity; however, if very high reliability is required, it is useful to employ both schemes together.

LPDQ: A self-scheduled TDMA MAC protocol for one-hop dynamic low-power wireless networks

Current Medium Access Control (MAC) protocols for data collection scenarios with a large number of nodes that generate bursty traffic are based on Low-Power Listening (LPL) for network synchronization and Frame Slotted ALOHA (FSA) as the channel access mechanism. However, FSA has an efficiency bounded to 36.8% due to contention effects, which reduces packet throughput and increases energy consumption. In this paper, we target such scenarios by presenting Low-Power Distributed Queuing (LPDQ), a highly efficient and low-power MAC protocol. LPDQ is able to self-schedule data transmissions, acting as a FSA MAC under light traffic and seamlessly converging to a Time Division Multiple Access (TDMA) MAC under congestion. The paper presents the design principles and the implementation details of LPDQ using low-power commercial radio transceivers. Experiments demonstrate an efficiency close to 99% that is independent of the number of nodes and is fair in terms of resource allocation.

Improving transmission reliability of low-power medium access control protocols using average diversity combining

Embedded computer systems equipped with wireless communication transceivers are nowadays used in a vast number of application scenarios. Energy consumption is important in many of these scenarios, as systems are battery operated and long maintenance-free operation is required. To achieve this goal, embedded systems employ low-power communication transceivers and protocols. However, currently used protocols cannot operate efficiently when communication channels are highly erroneous. In this study, we show how average diversity combining (ADC) can be used in state-of-the-art low-power communication protocols. This novel approach improves transmission reliability and in consequence energy consumption and transmission latency in the presence of erroneous channels. Using a testbed, we show that highly erroneous channels are indeed a common occurrence in situations, where low-power systems are used and we demonstrate that ADC improves low-power communication dramatically.

On the implant communication and MAC protocols for WBAN

AbstractRecent advances in micro‐electro‐mechanical systems, wireless communication, low‐power intelligent sensors, and semiconductor technologies have allowed the realization of a wireless body area network (WBAN). A WBAN provides unobtrusive health monitoring for a long period of time with real‐time updates to the physician. It is widely used for ubiquitous health care, entertainment, and military applications. The implantable and wearable medical devices have several critical requirements such as power consumption, data rate, size, and low‐power medium access control (MAC) protocols. This article consists of two parts: body implant communication, which is concerned with the communication to and from a human body using radio frequency (RF) technology, and WBAN MAC protocols, which presents several low‐power MAC protocols for a WBAN with useful guidelines including a case study of IEEE 802.15.4, PB‐TDMA, and SMAC protocols. In body implant communication, the in‐body RF performance is affected considerably by the implant's depth and different polarization combinations inside the human body as well as by the muscle and fat. We observe best performance at a depth of 3 to 5 cm and not close to the human skin. Furthermore, the study of low‐power MAC protocols highlights the most important aspects of developing a novel low‐power and reliable MAC protocol for a WBAN. Copyright © 2010 John Wiley & Sons, Ltd.

A Study of MAC Protocols for WBANs

The seamless integration of low-power, miniaturised, invasive/non-invasive lightweight sensor nodes have contributed to the development of a proactive and unobtrusive Wireless Body Area Network (WBAN). A WBAN provides long-term health monitoring of a patient without any constraint on his/her normal dailylife activities. This monitoring requires the low-power operation of invasive/non-invasive sensor nodes. In other words, a power-efficient Medium Access Control (MAC) protocol is required to satisfy the stringent WBAN requirements, including low-power consumption. In this paper, we first outline the WBAN requirements that are important for the design of a low-power MAC protocol. Then we study low-power MAC protocols proposed/investigated for a WBAN with emphasis on their strengths and weaknesses. We also review different power-efficient mechanisms for a WBAN. In addition, useful suggestions are given to help the MAC designers to develop a low-power MAC protocol that will satisfy the stringent requirements.

WUR-MAC: Energy efficient Wakeup Receiver based MAC Protocol

This paper discusses WUR-MAC, a medium-access control (MAC) protocol suited for wireless nodes equipped with a Wakeup Receiver (WUR). Unlike other protocols, the WUR-MAC takes advantage of the WUR ultra-low power listening mode leaving it permanently active to wait for incoming requests. Due to the ultra low power nature of these radio receivers, energy consumption and latency can be optimized at the same time. Energy consumption of the combined physical and MAC layer of a WUR based design is compared to efficient schedule based low power MAC protocols using the same main underlying transceiver without a wakeup radio receiver. WUR-MAC is based on proven MAC concepts but avoids complicated algorithms that are needed to synchronize nodes in traditional WSNs. Simulation results show that with typically low traffic, the average power consumption of schedule-based MACs is significantly higher than by using WUR-MAC only in the case where very low power Wakeup Receivers (<40 μW always on) are used. Delay is improved in any case due to the always on nature of the Wakeup Receiver.