1. Design of medical-grade wireless LAN
Sunghwa Son
Adviser: Prof. Kyung-Joon Park

2. Motivation
Why hospital’s environment goes to wireless?

3. 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!

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

5. IEEE e is sufficient?
Check current standard IEEE e guarantees QoS for medical applications or not with ns2 simulation
IEEE e 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

6. Default EDCA Parameters for each AC
Basics of IEEE e
DCF in
EDCA in e 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

7. 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 –
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

8. 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 –
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

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

10. 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

11. Simulation-1 result

12. 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

13. Cyber-physical Systems Integration Group
Simulation-2 result
Cyber-physical Systems Integration Group

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