Paper presentation Ultra-Portable Devices Paper: A. C. W. Wong, G. - - PowerPoint PPT Presentation

Paper presentation – Ultra-Portable Devices

Paper: Presented by:

• 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.

Dejan Radjen

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Outline

• Introduction
• Transceiver Definition
• Transceiver Architecture
• Hardware Implementation
• Experimental Results
• Summary and Conclusions

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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

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Introduction

SensiumTM SoC block diagram

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

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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

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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

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Transceiver Architecture

Transceiver block diagram

Hardware Implementation

• Dual conversion sliding-IF architecture
• Superior image-rejection than low-IF architecture
• Less DC-offset problem than zero-IF architecture

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Receiver

Hardware Implementation

• FSK modulation, 7-bit I and Q signals
• Power control established through feedback around the

transmit buffer

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Transmitter

Hardware Implementation

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Synthesizer

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Measurement Results

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Measurement Results

Chip Photograph Area: 7mm2

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

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