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A statistical frame based TDMA protocol for human body communication.

Nie Z, Li Z, Huang R, Liu Y, Li J, Wang L - Biomed Eng Online (2015)

Bottom Line: A beacon frame with the contained synchronous and poll information is designed to reduce the possibility of collisions of request frames.Dynamic time slot allocation mechanism is presented to manage the burst traffic and reduce the active period in each beacon period.The theory analysis is proceed and the result is evaluated in the hardware platform.

View Article: PubMed Central - PubMed

Affiliation: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518005, China. zd.nie@siat.ac.cn.

ABSTRACT

Background: Human 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.

Methods: The 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.

Results: To 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.

Conclusions: With 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.

No MeSH data available.


Related in: MedlinePlus

Figure for HBC development platform. This figure aims to demonstrate the printed circuit board (PCB) of our independently developed HBC platform.
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Fig6: Figure for HBC development platform. This figure aims to demonstrate the printed circuit board (PCB) of our independently developed HBC platform.

Mentions: As shown in Figure 5, the ARM processor is in charge of system controlling, data gathering and processing. The six kinds of frames (shown in Table 1) are formed in ARM, not including cyclic redundancy check (CRC) bytes which are formed in FPGA. The MAC protocol tasks and the default time slots are also implemented in ARM on the sensor nodes through programming. Embedded C programming language is used in programming which is debugged in the compiler environment Keil uvision4. The program is downloaded to ARM through J-link. The workflow of the program is shown in Figure 2. For data transmission, the ARM processor reads data from the secure digital memory card (SD card) and then modulate it into a 40 MHz square wave which falls within the specified frequency band range for HBC [42]; the square wave is sent to FPGA through serial peripheral interface (SPI), after which it is filtered by a band pass filter (BPF) and becomes a sine wave of the same frequency. The sine wave is passed to the signal electrode and transmit through our body. Our body is able to transmit the signals through capacitive coupling. As to the RX part, the signal is gathered by the input electrode and then filtered by a band-pass filter (BPF); then signal is demodulated by a logarithmic amplifier; at last, the signal is sent to the comparator through which the original signal is reverted; Clock and data recovery (CDR) is done in FPGA. The figure for experimental platform is shown in Figure 6. The coordinator as well as each HBC slave node is equipped with an electrode, data rates supported by this platform are up to 10 Mbps, meeting the demands of the latest entertainment and healthcare services.Figure 6


A statistical frame based TDMA protocol for human body communication.

Nie Z, Li Z, Huang R, Liu Y, Li J, Wang L - Biomed Eng Online (2015)

Figure for HBC development platform. This figure aims to demonstrate the printed circuit board (PCB) of our independently developed HBC platform.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4495947&req=5

Fig6: Figure for HBC development platform. This figure aims to demonstrate the printed circuit board (PCB) of our independently developed HBC platform.
Mentions: As shown in Figure 5, the ARM processor is in charge of system controlling, data gathering and processing. The six kinds of frames (shown in Table 1) are formed in ARM, not including cyclic redundancy check (CRC) bytes which are formed in FPGA. The MAC protocol tasks and the default time slots are also implemented in ARM on the sensor nodes through programming. Embedded C programming language is used in programming which is debugged in the compiler environment Keil uvision4. The program is downloaded to ARM through J-link. The workflow of the program is shown in Figure 2. For data transmission, the ARM processor reads data from the secure digital memory card (SD card) and then modulate it into a 40 MHz square wave which falls within the specified frequency band range for HBC [42]; the square wave is sent to FPGA through serial peripheral interface (SPI), after which it is filtered by a band pass filter (BPF) and becomes a sine wave of the same frequency. The sine wave is passed to the signal electrode and transmit through our body. Our body is able to transmit the signals through capacitive coupling. As to the RX part, the signal is gathered by the input electrode and then filtered by a band-pass filter (BPF); then signal is demodulated by a logarithmic amplifier; at last, the signal is sent to the comparator through which the original signal is reverted; Clock and data recovery (CDR) is done in FPGA. The figure for experimental platform is shown in Figure 6. The coordinator as well as each HBC slave node is equipped with an electrode, data rates supported by this platform are up to 10 Mbps, meeting the demands of the latest entertainment and healthcare services.Figure 6

Bottom Line: A beacon frame with the contained synchronous and poll information is designed to reduce the possibility of collisions of request frames.Dynamic time slot allocation mechanism is presented to manage the burst traffic and reduce the active period in each beacon period.The theory analysis is proceed and the result is evaluated in the hardware platform.

View Article: PubMed Central - PubMed

Affiliation: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518005, China. zd.nie@siat.ac.cn.

ABSTRACT

Background: Human 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.

Methods: The 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.

Results: To 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.

Conclusions: With 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.

No MeSH data available.


Related in: MedlinePlus