GWT/IEEE Joint Seminar Twin Cities May 24 , 2017

GWT/IEEE Joint SeminarTwin Cities – May 24th, 2017

Bluetooth Low Energy (BLE) Communication System for Medical Applications & Medical Body Area Network (MBAN) SystemsDavid Nghiem, Ph.D.

www.globalwirelesstechnology.com Minneapolis, Minnesota

BLE Communication System for Medical Applications


Medical Device & Sensor External Communicator

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BLE Communication System for Medical Applications


Life-critical Medical Device External Communicator

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Bluetooth Low Energy (BLE) 4.21) More Power Efficiency: Introduces refinements that help Bluetooth smart devices

save even more energy.2) Data Throughput Increase: Up to 2.5x faster with a packet capacity increase of 10x vs.

previous versions.3) Highly Secure: Features FIPS-compliant encryption ensuring confidential data stays

that way.4) Industry-leading Privacy: Keeps Bluetooth smart devices from being hacked.5) Flexible Internet Connectivity Options: Extend the reach of power-efficient devices to

the Internet.

Bluetooth® low-energy (BLE) technology has become a very promising option forwireless medical-implant applications.

Bluetooth 5 will quadruple the range, double the speed, and provide an eight-foldincrease in data broadcasting capacity of low energy Bluetooth transmissionscompared to Bluetooth 4.x, which could be important for IoT applications wherenodes are connected throughout a whole house

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https://en.wikipedia.org/wiki/Internet_of_things


BLE Challenges for Medical Applications

• An increased body loss at the ISM frequencies: 2,400.00 MHz – 2,483.50 MHz

• Common interference sources: Wi-Fi system, wireless power-charging system, microwave-oven, etc.

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Wi-Fi Channels in 2.4 GHz ISM Spectrum

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MBAN Frequency Band

• The FCC has approved the allocation of 40 MHz of spectrum bandwidth for medical BAN low-power, wide-area radio links at the 2360-2400 MHz band. This will allow off-loading MBAN communication from the already saturated standard Wi-Fi spectrum to a standard band.

• The 2360-2390 MHz frequency range is available on a secondary basis. Usage of the 2360-2390 MHz frequencies are restricted to indoor operation at health-care facilities and are subject to registration and site approval by coordinators to protect aeronautical telemetry primary usage.

• Operation in the 2390-2400 MHz band is not subject to registration or coordination and may be used in all areas including residential.

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A lesson to learn from Cell-phone system: User’s hand affects system performance & SAR

Mid channel: 836.60 MHz

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User’s Hand Affects System Performance

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SAR without User’s Hand

One gram averaged SAR limit = 1.6 mW/g

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User’s Hand Affects SAR

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Obama versus Trump

www.globalwirelesstechnology.com Minneapolis, Minnesota 15


Current SAR Testing Positions & Limits

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SAR Simulation

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Cell-phone Worst Case

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836.60 MHz Dipole with Worst-case Phantom for Human Head

Phantom material: Dielectric constant = 46.0 – Conductivity = 0.75 - Density = 1030Transmitting Power = 2 Watts = 33 dBm

Max SAR = 72.5 mW/gOne gram averaged SAR = 12.50 mW/g

One gram averaged SAR Limit = 1.6 mW/gTen gram averaged SAR = 6.25 mW/g

Ten gram averaged SAR Limit = 4.0 mW/gHow about SAR for human hand?

1 mm

200 mm Width x 300 mm Length x 150 mm Height

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The Worst-case SAR Testing using the Current Human-head Phantom (SAM)

One gram averaged SAR limit = 1.6 mW/gHow do we measure the worst-case SAR using the current human-head

phantom (SAM: Specific Anthropomorphic Mannequin)?

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BLE Antenna System:

External Device

&

Implant Device

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External DeviceAntenna Location

Cable Loss = 3.2 dB

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External Device: Antenna Efficiency & Max Gain in Free space

Lowest Channel (2.402 GHz)Efficiency = -0.93 dB Max Gain = 4.23 dBiMid Channel (2.444 GHz)Efficiency = -0.73 dB (84.5%)Max Gain = 4.37 dBiHighest Channel (2.480 GHz)Efficiency = -1.01 dBMax Gain = 4.16 dBi

Note: Multiple polarization

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External Device: Antenna Efficiency & Max Gain for Hand-held Scenario One

Lowest Channel(2.402 GHz)Efficiency = -3.05 dB Max Gain = 2.54dBiMid Channel (2.444 GHz)Efficiency = -2.91 dB (51.2%)Max Gain = 2.44 dBiHighest Channel (2.480 GHz)Efficiency = -3.17 dB

Max Gain = 2.20 dBi

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External Device: Antenna Efficiency & Max Gain for Hand-held Scenario Two

Lowest Channel(2.402 GHz)Efficiency = -17.18 dB Max Gain = -10.12 dBiMid Channel (2.444 GHz)Efficiency = -17.28 dB (1.88%)Max Gain = -10.02 dBiHighest Channel (2.480 GHz)Efficiency = -17.60 dB

Max Gain = -10.12 dBi

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External Device: Antenna Efficiency & Max Gain for Body-worn Scenario

Lowest Channel(2.402 GHz)Efficiency = -11.50 dB Max Gain = -2.40 dBiMid Channel (2.444 GHz)Efficiency = -11.21 dB (7.57%)Max Gain = -1.74 dBiHighest Channel (2.480 GHz)Efficiency = -11.18 dB

Max Gain = -1.61 dBi

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Implant Antenna:

Implant Depth = 2 cm85% Lean Ground Beef was used to simulate body tissues.

Is it feasible to design an implant antenna that works for all scenarios: free-space, prior to implant (over metal tray), during implant and post implant?

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Implant Antenna on Human Body

Lowest Channel (2.402 GHz)Efficiency = -30.51 dBMax Gain = -21.97 dBi

Mid Channel (2.444 GHz)Efficiency = -30.25 dB (0.095%)Max Gain = -21.08 dBi

Highest Channel (2.480 GHz)Efficiency = -30.98 dBMax Gain = -22.87 dBi

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BLE System Link Budget – Mid Channel (2.444 GHz)2 cm Implant DepthCommunication Distance = 1.0m

• Transmitting power of implant = 0.0 dBm

• Averaged implant antenna gain (efficiency) = -30.25 dBi

• Averaged hand-held device antenna gain (efficiency) = -17.28 dBi (user’s hand effect)

• Free space path loss for a distance of 1.0m = 40.20 dB

• Receiving power of hand-held device = 0.0 dBm -17.28 dB – 40.20 dB –30.25 dB = -87.73 dBm

• Receiving sensitivity = -93.00 dBm for a data rate of 1 Mbps

• Link margin = 5.27 dB

• Discussion on Signal-to-Noise ratio (SIR), Polarization Loss and Fading Allowance

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Wi-Fi Signal Finder Application

Wi-Fi/Bluetooth Antenna Location

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Discussion on Mutual Coupling Testing

Hand-held Scenario One Hand-held Scenario Two Body-worn Scenario

Example: Mutual coupling between implant & hand-held device = -70.0 dB Transmitting Power of implant = 0.0 dBm

Receiving Power of hand-held device = 0.0 dBm – 70.0 dB = -70.0 dBm

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BLE System Link Budget – Mid Channel (2.444 GHz)2 cm Implant DepthCommunication Distance = 2.0 m

• Transmitting power of implant = 0.0 dBm


• Averaged hand-held device antenna gain (efficiency) = -17.28 dBi (user’s hand effect)

• Free space path loss for a distance of 2.0 m = 46.22 dB

• Receiving power of hand-held device = 0.0 dBm -17.28 dB – 46.22 dB –30.25 dB = -93.75 dBm


• Link margin = -0.75 dB (system fails)


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Discussion on System Testing

Implant Device

External Device:Cell phone GWT BLE/MBAN USB Dongle

Termite App

nRF UART v.2 App

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Can a surgical headlamp system interfere with MICS system?

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BFW Maxenon Xi 300 watt XenonSurgical Headlamp System Interferes with MICS Systems


BFW Maxenon Xi 300 watt Xenon System : OFFNoise was measured at 2 meters from the unit!


200 MHz 600 MHz

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BFW Maxenon Xi 300 watt Xenon System : ONNoise was measured at 2 meters from the unit!


200 MHz 600 MHz

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BFW Maxenon Xi 300 watt Xenon System : ONNoise was measured at 2 meters from the unit!


100 MHz 3000 MHz

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Discussion on Coexistence Interference

1) Establish a reliable coexistence testing methodology for a conservative scenario.

2) Characterize the 2.4 GHz spectrum in a hospital environment.

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Hospital


Airport


Resident (Wi-Fi + Microwave Oven + Bluetooth)


Wireless Far-field Power-charging System


For more info, please visit: www.energous.com

Tx Gain = 21 dBiTx Power = 25 dBm

Rx Gain = 0.0 dBiA Radio Frequency (RF) system, similar to a Wi-Fi

system, delivers safe wire-free charging energy at

distances of up to approximately 15 feet from a

transmitter to a receiver device.

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http://www.energous.com/

Wireless far-field power-charging system could interfere with BLE medical systems!


Tx Gain = 21 dBiFSPL = 66.24 dB (20m, 2.45 GHz)

Tx Power = 25 dBm

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GWT Wireless Non-far-field Power-charging System(Conducting Loss Only)


Microwave Oven


If the Bluetooth system is typically farther than 5 meters from the microwave, the Bluetooth performance does

not degrade!

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Medical Body Area Network (MBAN)

A body area network (BAN), also referred to as a wireless body area network (WBAN) or a body

sensor network (BSN), is a wireless network of wearable computing devices. BAN devices may be

embedded inside the body, implants, may be surface-mounted on the body in a fixed position or

may be accompanied devices which humans can carry in different positions, in clothes pockets,

by hand or in various bags.

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MBAN Frequency Band

• The FCC has approved the allocation of 40 MHz of spectrum bandwidth for medical BAN low-power, wide-area radio links at the 2360-2400 MHz band. This will allow off-loading MBAN communication from the already saturated standard Wi-Fi spectrum to a standard band.

• The 2360-2390 MHz frequency range is available on a secondary basis. Usage of the 2360-2390 MHz frequencies are restricted to indoor operation at health-care facilities and are subject to registration and site approval by coordinators to protect aeronautical telemetry primary usage.

• Operation in the 2390-2400 MHz band is not subject to registration or coordination and may be used in all areas including residential.

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What are the main technical requirements for MBAN Devices?

• Maximum Transmitter Power

For transmitters operating in the 2360-2390 MHz band, the maximum EIRP shall not exceed the lesser of 1 mW (0 dBm). For transmitters operating in the 2390-2400 MHz band, the maximum EIRP shall not exceed the lesser of 20 mW (13 dBm).

• Transmitter Operation

The transmitter must cease operating in the 2360-2390 MHz band if it does not receive a control message permitting such operation such as when the device is out of range or operated outdoors. The shutdown process shall commence within 45 ms after loss of the communication link or receipt of the shutdown command form the MedRadio programmer transmitter. Transmissions may be redirected from the 2360-2390 MHz band to the 2390-2400 MHz band by use of a control message.

• Authorized Bandwidth

An aggregate channel bandwidth of up to 5 MHz – consistent with existing MedRadio rules.

• Frequency Stability

+/- 100 ppm over 0°C to 55°

• Frequency Monitoring

It is expected that contention-based protocols, including listen-before-talk (LBT), frequency monitoring, time slot synchronization and frequency hopping may be utilized.

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Body-worn Device Scenario


Body-worn Device Scenario: Azimuth Pattern


Efficiency = -11.0 dB (7.95%) – Max Gain = -2.15 dBiMid frequency = 2380 MHz

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MBAN System Link Budget for Healthcare FacilitiesStationary External Hub - Body-worn DeviceCommunication Distance = 2.0 m

• Transmitting power for a stationary external hub = 0.0 dBm

• Maximum transmitting antenna gain is less than or equal to 0.0 dBi to satisfy the EIRP requirement of 0 dBm.

• Averaged transmitting antenna gain (efficiency) = -3 dBi

• Free space path loss for a distance of 2.0 m @ 2.380 GHz = 45.99 dB

• Averaged body-worn device antenna gain (efficiency) = -11.00 dBi

• Receiving power of implant device = 0.0 dBm – 3.0 dB – 45.99 dB – 11.00 dB = -59.99 dBm




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MBAN System Link Budget for Healthcare FacilitiesHand-held External Hub - Body-worn DeviceCommunication Distance = 2.0 m

• Transmitting power for a hand-held external hub = 0.0 dBm

• Averaged transmitting antenna gain (efficiency) = -17.15 dBi (user’s hand effect)


• Averaged body-worn device antenna gain (efficiency) = -11.00 dBi

• Receiving power of implant device = 0.0 dBm – 17.15 dB – 45.99 dB –11.00 dB = -74.14 dBm




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MBAN System Link Budget for Healthcare FacilitiesStationary External Hub - Implant Device with 2 cm Implant Depth - Communication Distance = 2.0 m

• Transmitting power for a stationary external Hub = 0.0 dBm

• Maximum transmitting antenna gain is less than or equal to 0.0 dBi to satisfy the EIRP requirement of 0 dBm.

• Averaged transmitting antenna gain (efficiency) = -3 dBi



• Receiving power of implant device = 0.0 dBm – 3.0 dB – 45.99 dB – 30.00 dB = -78.99 dBm




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MBAN System Link Budget for Healthcare FacilitiesHand-held External Hub - Implant Device with 2 cm Implant Depth - Communication Distance = 2.0 m

• Transmitting power for a hand-held external hub = 0.0 dBm

• Averaged transmitting antenna gain (efficiency) = -17.15 dBi (user’s hand effect)



• Receiving power of implant device = 0.0 dBm – 17.15 dB – 45.99 dB –30.00 dB = -93.14 dBm


• Link margin = -0.14 dB (system fails)


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Is it feasible to design an antenna system to shape the radiation pattern?

Body-worn/Implant Device Scenario

Normalized Radiation Pattern

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GWT Solution

Body-worn/Implant Device Scenario

Normalized Radiation Pattern

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GWT CELL-PHONE CASE WITH EMBEDDED BLE/MBAN DIVERSITY ANTENNA SYSTEM & ELECTRONIC/RF CIRCUIT

Proprietary Information

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GWT CELL-PHONE CASE WITH EMBEDDED BLE/MBAN DIVERSITY ANTENNA SYSTEM & ELECTRONIC/RF CIRCUIT

Proprietary Information

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Q&AFor additional questions, please send an email to

[email protected]

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Documents

GWT/IEEE Joint Seminar Twin Cities May 24 , 2017