Tham khảo tài liệu 'emerging communications for wireless sensor networks part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | A new MAC Approach in Wireless Body Sensor Networks for Health Care 113 all possible scenarios. The Delivery Ratio graphic Fig. 10 b proves that the fact of scheduling data packets taking cross-layer constraints into account outperforms the first come first served discipline of the original DQ protocol by guaranteeing the QoS requirements of high reliability right message latency and enough battery lifetime to all body sensors transmissions in the BSN as described in Section . The use of DQBAN with the proposed cross-layer fuzzy-rule base scheduling algorithm reaches more than 95 of transmission successes even though 20 of the ECG sensors have critical battery constraints. Close to saturation limits DQBAN achievement is specifically superior to the original DQ protocol without any energy-aware policy . implementation D. and superior compared to implementation C. The slight raise in the Delivery Ratio in implementations A. and B. results from the growing number of body sensors in DTQ. That is it is easier to find a body sensor with the appropriate environmental conditions to be scheduled in the first place while others are reluctant to transmit. Further Fig. 10 d confirms that the use DQBAN is also appropriate in terms of Mean Packet Delay and still outperforms implementation B. as in all previous studied scenarios. c d Fig. 10. Average energy consumption per utile bit a - c Delivery Ratio b and Mean Packet Delay d in the homogenous Scenario 114 Emerging Communications for Wireless Sensor Networks Heterogeneous Scenario Fig. 11 illustrates the DQBAN MAC performance in a hospital scenario with heterogeneous traffic. The heterogeneous BSN is characterized by four specific medical body portable sensors defined in Table 2 a blood pressure body sensor a respiratory rate body sensor a real-time endoscope camera and a portable clinical PDA while the number of ECG body sensors increases from simulated iteration to iteration as previously explained. In .
