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A MAC protocol for medical monitoring applications of wireless body area networks.

Shu M, Yuan D, Zhang C, Wang Y, Chen C - Sensors (Basel) (2015)

Bottom Line: During these interruption slots, the coordinator can break the running superframe and start a new superframe.A contention access period (CAP) is only activated when there are more data that need to be delivered.Experimental results show the effectiveness of the proposed MAC protocol in WBANs with low urgent traffic.

View Article: PubMed Central - PubMed

Affiliation: School of Information Science and Engineering, Shandong University, Jinan 250100, China. shuml@sdas.org.

ABSTRACT
Targeting the medical monitoring applications of wireless body area networks (WBANs), a hybrid medium access control protocol using an interrupt mechanism (I-MAC) is proposed to improve the energy and time slot utilization efficiency and to meet the data delivery delay requirement at the same time. Unlike existing hybrid MAC protocols, a superframe structure with a longer length is adopted to avoid unnecessary beacons. The time slots are mostly allocated to nodes with periodic data sources. Short interruption slots are inserted into the superframe to convey the urgent data and to guarantee the real-time requirements of these data. During these interruption slots, the coordinator can break the running superframe and start a new superframe. A contention access period (CAP) is only activated when there are more data that need to be delivered. Experimental results show the effectiveness of the proposed MAC protocol in WBANs with low urgent traffic.

Show MeSH
The effects of the beacon interval and interrupt interval on time slot usage.
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f12-sensors-15-12906: The effects of the beacon interval and interrupt interval on time slot usage.

Mentions: Figure 12 shows the time slot utilization efficiencies of all of the MAC schemes. This performance indicator indicates how much time resource is used to transmit the urgent data for every scheme. For 802.15.4, the beacons and CAP periods are the factors that affect this indicator; while for I-MAC, the beacons and the interrupt slots are the factors. It can be seen from the figure that as the beacon interval and interrupt interval increase, the time slot usages of all of the MAC schemes decrease with the reduction of beacons. For all MAC schemes, the duty cycle of the coordinator is 100% due to the existence of monitoring applications of high data rates. For 802.15.4, to deliver the urgent data, a CAP period that at least occupies one of the total 16 time slots needs to be configured in a superframe. In this paper, such a CAP period is enough for transmitting the urgent data. Therefore, when the beacon interval increases, the time slot usage tends to 1/16. Compared to 802.15.4, the short interrupt slots exploited by I-MAC only occupy a small fraction of the total time slots. Therefore, I-MAC has higher time slot utilization efficiency than 802.15.4. As for the three I-MAC variations, the scheme with more interrupt slots has higher time slot utilization efficiency, but the advantage is not obvious.


A MAC protocol for medical monitoring applications of wireless body area networks.

Shu M, Yuan D, Zhang C, Wang Y, Chen C - Sensors (Basel) (2015)

The effects of the beacon interval and interrupt interval on time slot usage.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507673&req=5

f12-sensors-15-12906: The effects of the beacon interval and interrupt interval on time slot usage.
Mentions: Figure 12 shows the time slot utilization efficiencies of all of the MAC schemes. This performance indicator indicates how much time resource is used to transmit the urgent data for every scheme. For 802.15.4, the beacons and CAP periods are the factors that affect this indicator; while for I-MAC, the beacons and the interrupt slots are the factors. It can be seen from the figure that as the beacon interval and interrupt interval increase, the time slot usages of all of the MAC schemes decrease with the reduction of beacons. For all MAC schemes, the duty cycle of the coordinator is 100% due to the existence of monitoring applications of high data rates. For 802.15.4, to deliver the urgent data, a CAP period that at least occupies one of the total 16 time slots needs to be configured in a superframe. In this paper, such a CAP period is enough for transmitting the urgent data. Therefore, when the beacon interval increases, the time slot usage tends to 1/16. Compared to 802.15.4, the short interrupt slots exploited by I-MAC only occupy a small fraction of the total time slots. Therefore, I-MAC has higher time slot utilization efficiency than 802.15.4. As for the three I-MAC variations, the scheme with more interrupt slots has higher time slot utilization efficiency, but the advantage is not obvious.

Bottom Line: During these interruption slots, the coordinator can break the running superframe and start a new superframe.A contention access period (CAP) is only activated when there are more data that need to be delivered.Experimental results show the effectiveness of the proposed MAC protocol in WBANs with low urgent traffic.

View Article: PubMed Central - PubMed

Affiliation: School of Information Science and Engineering, Shandong University, Jinan 250100, China. shuml@sdas.org.

ABSTRACT
Targeting the medical monitoring applications of wireless body area networks (WBANs), a hybrid medium access control protocol using an interrupt mechanism (I-MAC) is proposed to improve the energy and time slot utilization efficiency and to meet the data delivery delay requirement at the same time. Unlike existing hybrid MAC protocols, a superframe structure with a longer length is adopted to avoid unnecessary beacons. The time slots are mostly allocated to nodes with periodic data sources. Short interruption slots are inserted into the superframe to convey the urgent data and to guarantee the real-time requirements of these data. During these interruption slots, the coordinator can break the running superframe and start a new superframe. A contention access period (CAP) is only activated when there are more data that need to be delivered. Experimental results show the effectiveness of the proposed MAC protocol in WBANs with low urgent traffic.

Show MeSH