Design of medical-grade wireless LAN Sunghwa Son ssh@dgist.ac.kr Adviser: Prof. Kyung-Joon Park 2018-09-20

Motivation Why hospital’s environment goes to wireless? 2018-09-20

Motivation Why hospital’s environment goes to wireless? Reducing cost of wire Providing mobility to patient - Eliminates crisscross wires or cables System-level reliability over wires However, we need medical-grade QoS for wireless! 2018-09-20

Medical-grade QoS Quality of Service (QoS) is one of important factors in wireless medical-grade network - Directly related to patients health condition 2018-09-20

IEEE 802.11e is sufficient? Check current standard IEEE 802.11e guarantees QoS for medical applications or not with ns2 simulation IEEE 802.11e provides QoS for wireless LAN applications with four levels of priority - Voice – AC_VO - Video – AC_VI - Best Effort – AC_BE - Background – AC_BK Enhanced Distributed Channel Access (EDCA) defines four levels as Access Category (AC) The levels of priority in EDCA are called access categories (ACs). Access Category Priority AC_VO (AC0) High AC_VI (AC1) AC_BE (AC2) AC_BK (AC3) Low 2018-09-20

Default EDCA Parameters for each AC Basics of IEEE 802.11e DCF in 802.11 EDCA in 802.11e 1 2 Access Category Priority CWmin CWmax AFISN AC_VO (AC0) High 7 15 2 AC_VI (AC1) 31 AC_BE (AC2) 1023 3 AC_BK (AC3) Low The levels of priority in EDCA are called access categories (ACs). Default EDCA Parameters for each AC 2018-09-20

Mapping to medical applications Alarm signals – infusion pump alarms, telemetry alarms Real-time streaming data – monitoring telemetry, ECG data Other medical applications – e-health applications Non-medical applications – email Service type AC Priority CWmin CWmax AFISN Alarm signals AC0 High 7 15 2 Real-time streaming data AC1 31 Other medical apps AC2 1023 3 Non-medical apps AC3 Low 2018-09-20

Mapping to medical applications Alarm signals – infusion pump alarms, telemetry alarms Real-time streaming data – monitoring telemetry, ECG data Other medical applications – e-health applications Non-medical applications – email Service type AC Priority CWmin CWmax AFISN Alarm signals AC0 High 7 15 2 Real-time streaming data AC1 31 Other medical apps AC2 1023 3 Non-medical apps AC3 Low 2018-09-20

Simple mapping is enough? IEEE 802.11e with medical traffic categorization insufficient to guarantee medical-grade QoS How can we know? We need motivating simulation! 2018-09-20

ns2 simulation-1 Measuring end-to-end delay of alarm with different number of ECG flows and CWmin of ECG transmission Parameter Value Alarm(AC0) ECG transmission(AC1) Number of nodes 1 N (1,5,10,15,20,25,30,35) Protocol type UDP Traffic Exponential traffic CBR traffic Burst_time 1 seconds Idle_time 999 seconds CW_MIN AC1 - 15,31,63,127,255 Total simulation time 1000 seconds 2018-09-20

Simulation-1 result 2018-09-20

ns2 simulation-2 Measuring throughput of ECG transmission with several value of CWmin of ECG transmission Parameter Value Alarm(AC0) ECG transmission(AC1) Number of nodes 1 Protocol type UDP Traffic Exponential traffic CBR traffic Data rate 26.6 kbps 800 kbps Burst_time 1 seconds Idle_time 999 seconds CW_MIN AC1 - 15,31,63,127,255,511 Total simulation time 1000 seconds 2018-09-20

Cyber-physical Systems Integration Group Simulation-2 result 2018-09-20 Cyber-physical Systems Integration Group

Summary Medical-grade QoS is central in medical WLAN IEEE 802.11e is insufficient for medical-grade QoS Several researches performed for enhancing QoS of WLAN and medical applications (next time) 2018-09-20