A statistical frame based TDMA protocol for human body communication

Abstract

BackgroundHuman body communication (HBC) using the human body as the transmission medium, which has been regarded as one of the most promising short-range communications in wireless body area networks (WBAN). Compared to the traditional wireless networks, two challenges are existed in HBC based WBAN. (1) Its sensor nodes should be energy saving since it is inconvenient to replace or recharge the battery on these sensor nodes; (2) the coordinator should be able to react dynamically and rapidly to the burst traffic triggered by sensing events. Those burst traffic conditions include vital physical signal (electrocardiogram, electroencephalogram etc.) monitoring, human motion detection (fall detection, activity monitoring, gesture recognition, motion sensing etc.) and so on. To cope with aforementioned challenges, a statistical frame based TDMA (S-TDMA) protocol with multi-constrained (energy, delay, transmission efficiency and emergency management) service is proposed in this paper.MethodsThe scenarios where burst traffic is often triggered rapidly with low power consumption and low delay is handled in our proposed S-TDMA. A beacon frame with the contained synchronous and poll information is designed to reduce the possibility of collisions of request frames. A statistical frame which broadcasts the unified scheduling information is adopted to avoid packet collisions, idle listening and overhearing. Dynamic time slot allocation mechanism is presented to manage the burst traffic and reduce the active period in each beacon period. An emergency mechanism is proposed for vital signals to be transmitted. The theory analysis is proceed and the result is evaluated in the hardware platform.ResultsTo verify its feasibility, S-TDMA was fully implemented on our independently-developed HBC platform where four sensor nodes and a coordinator are fastened on a human body. Experiment results show that S-TDMA costs 89.397 mJ every 20 s when the payload size is 122 bytes, 9.51% lower than Lightweight MAC (LMAC); the average data latency of S-TDMA is 6.3 ms, 7.02% lower than Preamble-based TDMA (PB-TDMA); the transmission efficiency of S-TDMA is 93.67%, 4.83% higher than IEEE 802.15.6 carrier sense multiple access/collision avoidance (CSMA/CA) protocol.ConclusionsWith respect to the challenges of HBC based WBANs, a novel S-TDMA protocol was proposed in this paper. Compared to the traditional protocols, the results demonstrate that S-TDMA successfully meets the delay and transmission efficiency requirements of HBC while keeping a low energy consumption. We also believe that our S-TDMA protocol will promote development of HBC in wearable applications.

Review: Emerging Trends in Healthcare Adoption of Wireless Body Area Networks

“…As a result, Nie et al 59 state concerns that need to be considered in HBC, including 1) increased mobility, as both the sensor nodes and the data aggregation device are located either in or on the human body; 2) lower power consumption to synchronize sensor nodes, as they are separated by no more than arm-span length; 3) battery size for nodes, which must be small but at the same time have a life span of several months; and 4) the requirement for effective management of burst data in the aggregator, as a result of frequent triggering of physiological alerts. 59 Considering these concerns, they have proposed a newer statistical frame-based time division multiple access (S-TDMA) protocol for use in HBC. Experimental evaluation of this protocol in relation to established protocols shows that S-TDMA demonstrates relatively lower energy consumption, has lower data latency, and a higher transmission-efficiency.…”

A Hybrid Lifetime Extended Directional Approach for WBANs

“…At the same time, idle listening wastes a lot of energy. Scheduled based MAC protocols in [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ] supply better solutions to the traffic related problems since there is no need to concern the contention and idle listening problems. A study of ultra-low power Time Division Multiple Access (TDMA) MAC protocols based on IEEE 802.15.4 is presented in [ 22 ].…”

“…Furthermore, they do not take the user priorities into consideration, leading the medical business especially the emergency traffic making no sense in limited time. S-TDMA [ 27 ] on the basis of IEEE 802.15.6 employs both TDMA and unified scheduling scheme for energy-efficiency. Nevertheless, the slots allocation does not ponder the traffic varieties in different user priorities.…”

Synthetic plasma and silicon tubular harness-based pure biological transistor amplifier circuit

“…This has enormous application in implanting electronic circuits inside the human body. One can put battery (power supply of the circuit) on the nearby human body skin surface [ 6 ] .…”