Coexistence of WBAN and WLAN in Medical Environments

Coexistence of WBAN and WLAN in Medical Environments Ruben de Francisco, Li Huang, and Guido Dolmans IMEC Netherlands, Holst Centre, Eindhoven, The Netherlands Dohwan Kim

Table of contents Coexistence of WBAN and WLAN Scenario Coexistence test results Conclusion

Coexistence of WBAN and WLAN WBAN (802. 15. 4) – CC 2520 zigbee Frequency : 2. 4 GHz Occupied bandwidth : 2 MHz Nominal output power : Up to 5 d. Bm Receiver sensitivity : -98 d. Bm WLAN (802. 11 g) – Linksys WRT 54 G Frequency : 2. 4 GHz Occupied bandwidth : 16. 6 MHz Nominal output power : 18 d. Bm Receiver sensitivity : -67 d. Bm at 54 Mbps

Coexistence of WBAN and WLAN Zigbee channel 11, 12, 13, and 14 use same frequency as Wi. Fi channel 1. Output power of zigbee is less than that of Wi. Fi. Zigbee may be ignored.

Coexistence of WBAN and WLAN example WBAN receiver experiences interference from a collocated WLAN transmitter. WLAN receiver experiences interference from a collocated WBAN transmitter. In this study, we uniquely consider interference between WBAN receiver and WLAN transmitter.

Scenario

Scenario There are two node topology. Two node topology consist of LOS channel between transmitter and receiver, and also between interferer and receiver. Scenario 1 Distance between T and R is 69 cm. Distance between R and I is 200 cm. Scenario 2 Distance between T and R is 312 cm. Distance between R and I is 24 cm.

Scenario 802. 15. 3 link use channel 20 centered at 2450 MHz. 802. 15. 4 transmit power is used -18 d. Bm, -4 d. Bm, 0 d. Bm and 5 d. Bm. 802. 11 g use three channel such as channel 9 (2452 MHz), channel 7 (2442 MHz) and channel 5 (2432 MHz). 802. 11 g channels used are represented as frequency offset Channel 9 (2452 MHz) -> 2452 – 2450 = 2 MHz Channel 7 (2442 MHz) -> 2450 – 2442 = 8 MHz Channel 5 (2432 MHz) -> 2450 – 2432 = 18 MHz

Coexistence test results Scenario 1 Scenario 2

Conclusion The system must select optimal channel. MAC and networking mechanisms must be improved. The devices shouldn’t locate along wall to avoid distortion effect.