M. Sanaullah Chowdhury

A power efficient MAC protocol for wireless body area networks

Applications of wearable and implanted wireless sensor devices are hot research area. A specialized field called the body area networks (BAN) has emerged to support this area. Managing and controlling such a network is a challenging task. An efficient media access control (MAC) protocol to handle proper management of media access can considerably improve the performance of such a network. Power consumption and delay are major concerns for MAC protocols in a BAN. Low cost wakeup radio module attached with sensor devices can help reduce power consumption and prolong the network lifetime by reducing idle state power consumption and increasing sleep time of a BAN node. In this article, we propose a new MAC protocol for BAN using out of band (on-demand) wakeup radio through a centralized and coordinated external wakeup mechanism. We have compared our method against some existing MAC protocols. Our method is found to be efficient in terms of power consumption and delay.

Throughput and delay limits of chirp spread spectrum-based IEEE 802.15.4a

The IEEE 802.15.4 standard is designed to provide a low-power, low data rate protocol offering a high reliability. As an amendment to this standard, IEEE 802.15.4a introduces new options for physical layer to enable precision ranging. In this work, we analyzed the theoretical throughput and delay bounds of the unslotted version of chirp spread spectrum PHY-based 802.15.4a. The formulae for transmission between one sender and one receiver for an ideal channel with no transmission errors are given. The throughput and delay bounds are derived for different frequency bands and data rates. Additionally, to measure spectral utilization, we measured the bandwidth efficiency for both the standards. We also compared our results with IEEE 802.15.4. The comparative analysis concludes that the performance of 802.15.4a exceeds 802.15.4 in terms of throughput and delay. The analytical results of throughput are verified by computer simulations. Copyright

Multi-hop medium access control protocol for low energy critical infrastructure monitoring networks using wake-up radio

The IEEE 802.15.4K Task Group was formed recently to address the low energy critical infrastructure monitoring networks. The aim is to collect scheduled and event data from a large number of non-mains powered endpoints that are widely dispersed. The application requirements include reliable data transfer, energy efficiency, and long deployment lifetime. To meet the low energy critical infrastructure monitoring network requirements, we propose a multihop medium access control protocol where the scheduled or event data are routed to the coordinator through the cluster heads. The power consumption of the cluster heads is critical as they use more power than the normal endpoints. Our protocol uses the wake-up radio approach from cluster head to cluster head communication and an efficient guaranteed time slots allocation scheme to minimize the power consumption of the cluster heads. We derive analytical expressions for the average power consumption of cluster heads as well as ordinary endpoints. The results show that our proposed protocol outperforms the IEEE 802.15.4 MAC and SCP MAC in terms of power consumption. High power efficiency is achieved in both the cluster heads and normal endpoints. Copyright

Framed slotted aloha based MAC protocol for low energy critical infrastructure monitoring networks

SUMMARY Recently, the IEEE TG4k has been formed to amend the IEEE 802.15 family to address the low energy critical infrastructure monitoring networks. The purpose is to facilitate point to multi-thousands of point communication to collect the scheduled and event data from a large number of nonmains powered endpoints that are widely dispersed. It should support low energy operation, which is necessary for multiyear battery life. Other major features are application data rate up to 40 Kb/s, thousands of endpoints per mains powered infrastructure, asymmetric application data flow, small and infrequent messages, tolerant to data latency, etc. In this paper, we present a discussion on low energy critical infrastructure monitoring networks. We propose a medium access control protocol based on framed slotted aloha for these networks. We investigated probable packet sizes, energy consumptions, battery lifetime and the success rate for our protocol. The proposed protocol is simple to implement. Simulation results show that it is efficient in terms of packet success rate, energy consumption, and battery lifetime.Copyright

Energy Efficient MAC Protocol for Low-Energy Critical Infrastructure Monitoring Networks Using Wakeup Radio

Critical infrastructure monitoring applications are rapidly increasing. Application requirements include reliable data transfer, energy efficiency, and long deployment lifetime. These applications must also be able to operate in an extremely low-cost communication environment in order to be attractive to potential users. A low rate wireless personal area network can help control and manage the operations of such applications. In this paper, we present a medium access control (MAC) protocol for low-energy critical infrastructure monitoring (LECIM) applications. The proposed MAC protocol is based on a framed slotted aloha multiple access schemes. For downlink communication, we use a wakeup radio approach to avoid complex bookkeeping associated with the traditional MAC protocols. Analytical expressions for power consumption and delay are derived to analyze and compare the performance of our proposed protocol with the existing well-known T-MAC, B-MAC, X-MAC, ZigBee, and WiseMAC protocols. It is shown that our proposed protocol outperforms all the other protocols in terms of power consumption and delay.

Throughput limits of UWB based 802.15.4a

We investigate the maximum throughput and minimum delay for the unlostted version of the IEEE 802.15.4a using Ultra Wide Band (UWB). The throughput and delay limits are calculated for different data rates along with the formulae. UWB based 802.15.4a can achieve maximum throughput of 701 Kbps with a data rate of 851 Kbps.

Throughput, delay and bandwidth efficiency of IEEE 802.15.4a using CSS PHY

The IEEE 802.15.4 standard is a short range wireless technology. As a revision to this standard, IEEE 802.15.4a introduces new options for PHY (physical layer) to enable ranging. In this paper, we investigate the theoretical maximum throughput and minimum delay of the un-slotted version of 802.15.4a using CSS (Chirp Spread Spectrum) PHY. The throughput and delay limits are derived for different frequency bands and data rates along with the formulae. Moreover, we calculate the bandwidth efficiency for both the standards. The comparative analysis concludes that the performance of 802.15.4a surpasses 802.15.4 in terms of throughput and delay.

Studies of Scattering, Reflectivity, and Transmitivity in WBAN Channel: Feasibility of Using UWB

The Wireless Personal Area Network (WPAN) is one of the fledging paradigms that the next generation of wireless systems is sprouting towards. Among them, a more specific category is the Wireless Body Area Network (WBAN) used for health monitoring. On the other hand, Ultra-Wideband (UWB) comes with a number of desirable features at the physical layer for wireless communications. One big challenge in adoption of UWB in WBAN is the fact that signals get attenuated exponentially. Due to the intrinsic structural complexity in human body, electromagnetic waves show a profound variation during propagation through it. The reflection and transmission coefficients of human body are highly dependent upon the dielectric constants as well as upon the frequency. The difference in structural materials such as fat, muscles and blood essentially makes electromagnetic wave attenuation to be different along the way. Thus, a complete characterization of body channel is a challenging task. The connection between attenuation and frequency of the signal makes the investigation of UWB in WBAN an interesting proposition. In this paper, we study analytically the impact of body channels on electromagnetic signal propagation with reference to UWB. In the process, scattering, reflectivity and transmitivity have been addressed with analysis of approximate layer-wise modeling, and with numerical depictions. Pulses with Gaussian profile have been employed in our analysis. It shows that, under reasonable practical approximations, the human body channel can be modeled in layers so as to have the effects of total reflections or total transmissions in certain frequency bands. This could help decide such design issues as antenna characteristics of implant devices for WBAN employing UWB.