Paper presentation – Ultra-Portable Devices Paper: A. C. W. Wong, G. Kathiresan, et al. A 1V Wireless Transceiver for an Ultra Low Power SoC for Biotelemetry Applications, ESSCIRC, pp 127-130, 2007. Presented by: Dejan Radjen 2010-06-07 Paper Presentation - Ultra Portable Devices 1
Outline • Introduction • Transceiver Definition • Transceiver Architecture • Hardware Implementation • Experimental Results • Summary and Conclusions 2010-06-07 Paper Presentation - Ultra Portable Devices 2
Introduction • The RF-transceiver presented in this paper is intended for Wireless Body Area Sensor Networks (WBASN) • Single-hop star topology is suitable for use in WBASN applications • Important to optimize the MAC protocols for this type of topologies 2010-06-07 Paper Presentation - Ultra Portable Devices 3
Introduction SensiumTM SoC block diagram 2010-06-07 Paper Presentation - Ultra Portable Devices 4
Transceiver Definition • The following license free frequency bands were chosen – The European 862-870 MHz SRD-band – North American 902-928 MHz ISM-band • Frequency band choices were based on a compromise between power consumption and antenna size • Physical distance: 1-10m 2010-06-07 Paper Presentation - Ultra Portable Devices 5
Transceiver Definition Link Budget - 71.8dB path loss 10m line-of-sight loss at 928MHz - Additional 20dB fade margin - 10 dB RF front-end losses (antenna, SAW-filter, matching) - Assumed -10dBm transmitted output power the received signal power is -101.8dBm - 200kHz channel bandwidth, 11dB SNR at the demodulator input required receiver NF is 8dB at 300kHz to achieve BER = 10 -3 2010-06-07 Paper Presentation - Ultra Portable Devices 6
Transceiver Definition • The choice of modulation is 2 level FSK • Frequency deviation = 50kHz, allows for low power design and meets spectral efficiency requirements • Data rate = 50kbits/s, chosen to meet more demanding vital sign measurements as ECG streaming 2010-06-07 Paper Presentation - Ultra Portable Devices 7
Transceiver Architecture Transceiver block diagram 2010-06-07 Paper Presentation - Ultra Portable Devices 8
Hardware Implementation Receiver • Dual conversion sliding-IF architecture • Superior image-rejection than low-IF architecture • Less DC-offset problem than zero-IF architecture 2010-06-07 Paper Presentation - Ultra Portable Devices 9
Hardware Implementation Transmitter • FSK modulation, 7-bit I and Q signals • Power control established through feedback around the transmit buffer 2010-06-07 Paper Presentation - Ultra Portable Devices 10
Hardware Implementation Synthesizer 2010-06-07 Paper Presentation - Ultra Portable Devices 11
Measurement Results 2010-06-07 Paper Presentation - Ultra Portable Devices 12
Measurement Results Chip Photograph Area: 7mm 2 2010-06-07 Paper Presentation - Ultra Portable Devices 13
Summary and Conclusions • A 1V RF transceiver for biotelemetry applications was presented • The current consumption is 2.1mA in receive mode and up to 2.6mA in transmitt mode 2010-06-07 Paper Presentation - Ultra Portable Devices 14
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