Selective packet discarding for effective congestion control in medical data transmission of remote healthcare monitoring system

A rapid advancement in Internet and sensors technology have enabled the development of Wireless Body Area Network (WBAN) technology which is targeted for Remote Healthcare Monitoring System (RHMS). This technology assists patients by continuously monitoring and detecting their health’s status through attaching or implanting several intelligent and lightweight bio-sensors into their bodies. Later, the collected medical data would be further processed by the medical authorities. If any abnormalities are detected, immediate medical actions would be carried out to avoid any consequences to patients. However, continuous transmission of medical data could lead to heavy traffics which can raise the issue of congestion in the network. It could degrade network performances in terms of higher delay and packet loss as well as lower throughput and packet delivery ratio (PDR). The consequences of these performances might be severed to the critical patients. Therefore, congestion should be avoided at the first place to ensure a reliable and efficient RHMS. In this thesis, a mechanism namely Priority Selective PacketTimeslot Medium Access Control (PSPT-MAC) is proposed to handle the aforementioned issues with regard to the Electrocardiogram (ECG) medical data. Thisproposed mechanism integrates three techniques which are ECG Packet Classification and Prioritization (ECG-PCP), a Prioritized Selective Packet Discarding (P-SPD) and Fragmentation based Slot Time Medium Access Control (FST-MAC) mechanisms. The PSPT-MAC is initiated by ECG-PCP to classify and prioritize the medical data based on the value of RR-interval. These data are classified into critical (high priority), abnormal (medium priority) and normal (low priority). Then P-SPD is carried out to discard the corrupted medical packets among normal and abnormal data. This is because these types of data do not pose a strict delay compared to critical data. To emphasize, the corrupted packets are not worth to be transmitted as they have higher chance of being drop which might cause retransmission. This could result in longer delay which affects the delivery of critical medical data and might waste the scarce network resources such as bandwidth and energy. The last phase which is FST-MAC helps in fragmentation of medical packets through a suitable slot time of 0.2 millisecond in the slotted CSMA/CA MAC IEEE 802.15.4 protocol in order to reduce delay in the network. The effectiveness of PSPT MAC mechanism has been tested and validated through simulation processes using a discrete event simulator tool namely OMNeT++ with the integration of framework INET 3.6.2. The findings have shown that the proposed PSPT-MAC always outperforms the two existing methods which are IEEE 802.15.4 and Fast Channel Assignment Medium Access Control (FCA-MAC) mechanisms. The PSPT-MAC has managed to achieve a significant reduction in delay approximately up to 78.67% and 74.42% compared to the standard IEEE 802.15.4 protocol and FCA-MAC mechanism respectively. Also, PSPT MAC mechanism has successfully decreased packet loss rate by 48.99% which has contributed in higher throughput and PDR compared to the standard IEEE 802.15.4 protocol under different number of nodes scenario.