1

Software Radio Technology

Dr. John ChapinCTO

Vanu, Inc.One Porter Square, Suite 18

Cambridge, MA 02474http://www.vanu.com

Presentation to NSMA conferenceRosslyn, VAMay 21, 2002

May 2002 2© 2002

Vanu, Inc.

• Overview– Founded September 1998– Spin-off from MIT SDR research project 1994–1998 – Software vendor

• Contracts– Military DARPA, JTRS Joint Program Office– Public Safety National Institute of Justice– Basic Research National Science Foundation, MDA– Automotive Telematics device for a Tier 1 Supplier– Surveillance Major defense conglomerate

May 2002 3© 2002

• Hardware Radio– Separate devices for different functions– Any fix or upgrade needs a hardware change PCS voice

Analog VHFAPCO P25

WLAN

Software Radio

• Software Radio– One device for many functions– Upgrade through software

change

May 2002 4© 2002

SDR status in USA

• Military– Harris Falcon II, Motorola WITS– Since 1999, all DOD tactical radio procurements must be SDR– Military SDR standard: Joint Tactical Radio System (JTRS)

• Civilian– SDR devices always certifiable as if they were legacy devices – FCC task force began in 1998 on SDR-specific rules– Docket 00-47

• Notice of Inquiry March 2000• NPRM December 2000• First R&O September 2001

May 2002 5© 2002

Different types of software radios

Dual-mode cell phone

• Modal SDR– Software controls and configures the radio– ASIC or analog hardware

• Reconfigurable SDR– All signal processing reconfigurable– Significant use of FPGA or assembly code

SpeakEasyAirNet

• Portable SDR (a.k.a. Pure SWR)– Software costs amortized over many

platforms– Easily upgrade hardware over time

VanuRadioScape

May 2002 6© 2002

SDR internals

Radio Front End antenna

RF tuningAnalog-Digital ConversionChannelizationNo waveform-specific processing

Embedded computerAll waveform-specific functions in software

Digital sa

mples

Analog at carrie

r frequency

IF

voice data

baseband

May 2002 7© 2002

Source: Mitola, Joseph. “Software Radio Architecture: A Mathematical Perspective”, IEEE JSAC, April 1999.

A: HF STR-2000B: COTS HandsetC: SWR Cell SiteD: SPEAKeasy IIV: Vanu, Inc. Software RadioX: Ideal Software Radio

Software Radio Phase Space

May 2002 8© 2002

Vanu status: Radio Front End for Agility

• Discrete components– Current TX limited to < 1 GHz, < 1 MHz

wide– Separate front ends for receive and

transmit– Cost $1000s

TE

CH

NO

LOG

Y P

RO

GR

ES

S

• Multiple-IC board– Prototype quantities this summer– 30-512 MHZ, worldwide cellular & PCS bands– Low power, full duplex, cost $100s

• Single IC– Ideal future platform, cost $10s– Manufacturers waiting for market to develop

May 2002 9© 2002

Vanu status: Processing for Flexibility

2.7

9.6

22

29

0

5

10

15

20

25

30

35

IS-136 30kHz

GSM200kHz

FamBand 25kHz

% o

f CPU Pentium III

800-1000 MHzStrongARM 200 MHz

May 2002 10© 2002

SDR tradeoffs

• Higher power consumption– Reconfigurable processing vs dedicated circuits– Primarily an issue for battery-powered devices

• Sensitivity/selectivity of radio front end– Challenging to achieve if highly agile system– Primarily an issue for surveillance, military applications

• Lower gain if antenna is multi-band– Easy solution: attach 2 or 3 antennas– Primarily an issue for handheld devices

• SDR ready today for many uses

May 2002 11© 2002

For more information

• http://www.sdrforum.org• FCC Docket 00-47• Two new books from Wiley

– Tuttlebee, W., editor– Chapters by all the major players in the field– Software Defined Radio: Origins, Drivers and

International Perspectives– Software Defined Radio: Enabling Technology

• http://www.vanu.com– John Chapin

jchapin@vanu.com