Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Are MICS and MedRadio bands suitable for IEEE 802.15.6?] Date Submitted: [17th March 2008] Source: [Maulin Patel] Company [Philips] Address [345 Scarborough Rd., Briarcliff Manor, NY 10510] Voice:[+1 914-945-6156], FAX: [+1 914-945-6330], E-Mail:[maulin.patel@philips.com] Re: [] Abstract: [This document investigates the suitability of MICS and MedRadio bands for the proposed IEEE 802.15.6 standard] Purpose: [To stimulate discussion on the suitability of MICS and MedRadio frequency bands for proposed IEEE 802.15.6 standard] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.

2. Are MICS and MedRadio Service bands suitable for IEEE 802.15.6? Maulin Patel Philips

3. Motivation • Band planning is the crucial first step • Evaluate frequency bands • Technical feasibility • Channel characteristics (Implanted and Wearable) • Antenna size, data rate • Regulatory requirements • Bandwidth, transmit power limit, duty cycle, SAR • Form consensus on the target frequency bands for 802.15.6 • Band planning would help in expediting • Channel modeling • Experimental validation • Narrow down currently broad and diverse application scope

4. Frequency bands under consideration • Medical Service • Medical Implant Communication Service (MICS) • Proposed Medical Device Radiocommunication Service (MedRadio Service) a.k.a. MEdical Data Service (MEDS) • Wireless Medical Telemetry System (WMTS) • General Service • Industrial, Scientific and Medical (ISM) • Ultra Wide Band (UWB)

5. WMTS • In Doc: IEEE 802.15-07-0728-00-0ban Kamya Yazandoost and Ryuji Kohno have highlighted the limitations of WMTS bands which render them unsuitable for IEEE 802.15.6 • Licensed band • Can only be used inside a healthcare facility • Only authorized healthcare providers are eligible users • Neither video nor voice transmission is permitted • Limited bandwidth • Only 6 MHz of contiguous bandwidth and14 MHz total

6. MICS • Allocated for communication between an implanted medical device and an external programmer/controller on following basis • Unlicensed • Shared • With primary users and other MICS devices • Secondary • Meteorological aids, Meteorological satellites and Earth exploration satellites are primary users • Non-interference • No harmful interference is cause to primary users • MICS band cannot be used for voice communications

7. MICS(Cont’d) • Allocated frequency 402MHz to 405MHz • Total of 3 MHz spectrum • Primary reasons for selecting these frequencies are • Better propagation characteristics for implants • Reasonable sized antenna for implants • Worldwide availability • Limited threat of interference to primary users

8. MICS (Cont’d) • Maximum bandwidth of the channel limited to 300KHz measured by 20dB • Channeling scheme is not specified • Half-duplex and full-duplex communication is allowed as long as bandwidth does not exceed 300KHz • Maximum transmit power limited to • -16dBm (25 μW) EIRP (FCC,ITU-R) • -16dBm (25 μW) ERP (ETSI) • EIRP limit is ~2.2 dB lower than ERP limit

9. MICS (Cont’d) • Communication session can only be initiated by external programmer/controller except in the case of ‘medical implant events’ when implants are authorized to start a session • i.e. when patient’s safety or well being is at risk

10. MICS (Cont’d) • Within 5 seconds prior to initiating a communications session, the programmer/control must monitor the channel or channels it intends to occupy for at least 10 milliseconds a.k.a “Listen Before Talk (LBT)” • The channel can be used for communication session if the no signal above the threshold power level is detected • Otherwise, scan all the candidate channels and the channel with the lowest ambient power level can be accessed • i.e. Adaptive Frequency Agility (AFA) • Above provisions are made to mitigate interference to primary users of the band and also to facilitate sharing of the channels

11. Limitations of MICS • MICS band is authorized to be used only for medical applications involving implants • Above provision precludes a vast majority of applications currently under consideration

12. Limitations of MICS • Only type of communication authorized by MICS is between an implant and the external programmer/controller • Communication between two or more implanted devices is not allowed • Above provision precludes communication between an implanted (glucose) sensor and an implanted drug (insulin) pump

13. Limitations of MICS • Communication between body worn devices is not allowed • Most applications under consideration by IEEE 802.15.6 TG require communication between body worn devices • i.e. ECG, EEG, EMG, Blood pressure, SpO2, Body temp etc.

14. Limitations of MICS • Implants cannot initiate a communication session except in the case of ‘medical implant event’ • Data must be polled by the external device subject to LBT and AFA • Periodic data transfer initiated by an implanted device is prohibited

15. Limitations of MICS • An out-of-band wake up mechanism may be needed for waking up the implant (i.e. inductive wake-up or ISM band wake-up) due to following reasons • 25μW EIRP wake-up signal may not retain enough power after overcoming heavy path loss offered by body tissues to be able to wake-up implanted radio • AFA and programmer/controller talks first provisions means wake-up channel cannot be fixed a priori

16. Limitations of MICS • According to PAR for IEEE 802.15.6, data rates upto 10Mbps should be supported • 300 KHz MICS channel cannot support such high data rates

17. Limitations of MICS • Adaptive Frequency Agility provision increases system complexity • PHY and MAC may need to switch the channels dynamically • Implants may have to scan candidate channels at the beginning of each session

18. MedRadio/MEDS • FCC has issued a Notice of Proposed Rule Making (NPRM 06-135 (2006)) for Medical Device Radiocommunication (MedRadio) Service • ETSI TR 102 343 V1.1.1 also proposes similar service • MedRadio services is intended for communications among implanted as well as body worn devices • To reduce system complexity MedRadio service waives AFA requirements but imposes stringent transmit power limit and duty cycle restriction

19. MedRadio/MEDS • Proposed frequency band • 401-402 MHz and 405-406 MHz • Maximum channel bandwidth • 100KHz/channel • Channels access options • Option 1 (Same as MICS) • LBT with AFA • -16dBm (25µw) EIRP limit • Option 2 • -36dBm (250nw) EIRP limit • Duty cycle <0.1% averaged over any one-hour period

20. Limitations of MedRadio/MEDS • The bands are only proposed (not allocated yet) • Only medical applications can be supported • Voice, video and CE applications may not be allowed • 100 KHz channel coupled with 0.1% duty cycle (Option 2) means effective throughput is extremely low • Option 1 (LBT with AFA) increase system complexity • May need dynamic channel switching capabilities • Maximum data rate would be significantly lower than those mandated by PAR

21. Summary • WMTS is not suitable • MICS can only support p2p link between an implant and external device • LBT with AFA requirements of MICS increase system complexity • MICS require specialized MAC and PHY solution • MedRadio/MEDS are not allocated • Proposed requirements puts severe restrictions on the type of applications that can be supported

22. Issues for Discussion • MICS band brings value by enabling implanted medical applications at the cost of added complexity • What are the costs and benefits for supporting MICS? • Which application use cases rely on MICS? • How big is the market for implanted devices? • What is the rationale for standardizing p2p link between an implanted device and an external programmer/controller? • How will the medical electronics industry respond to MICS standard?

23. Issues for Discussion (Cont’d) • If we want to support implanted and wearable applications then we need a dual band system • MICS (implant) + ISM or UWB (on body) • What will be the complexity of resulting system? • How to maintain seamless connectivity/interoperability between two PHYs? • Will it be consistent with PAR, 5C and IEEE regulations? • Are we aware of any existing dual band IEEE standard?

24. Issues for Discussion (Cont’d) • If we have to prioritize our efforts then where shall we zoom in our focus? • Which are core applications? • Wearable BAN or Implanted BAN?

25. Issues for Discussion (Cont’d) • Shall we design the standard for future availability of MedRadio service? • Issue an addendum or revision when it is ratified?