1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Are MICS and MedRadio bands suitable for IEEE ?]
Date Submitted: [17th March 2008]
Source: [Maulin Patel] Company [Philips]
Address [345 Scarborough Rd., Briarcliff Manor, NY 10510]
Voice:[ ], FAX: [ ],
Re: []
Abstract: [This document investigates the suitability of MICS and MedRadio bands for the proposed IEEE standard]
Purpose: [To stimulate discussion on the suitability of MICS and MedRadio frequency bands for proposed IEEE standard]
Notice: This document has been prepared to assist the IEEE P 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 P

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
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 ban Kamya Yazandoost and Ryuji Kohno have highlighted the limitations of WMTS bands which render them unsuitable for IEEE
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 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 , 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 (2006)) for Medical Device Radiocommunication (MedRadio) Service
ETSI TR 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 Maximum channel bandwidth
MHz and 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?
Possible approaches
Wearable first
Implanted first
Wearable + Implanted
Design standard for wearable applications and provide hooks for future enhancements for implanted applications
Design standard for implanted applications and provide hooks for future enhancements for wearable applications
Design standard for wearable and implanted applications

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?