Smart Radio: Spectrum Accessfor First Responders

Sponsored by: Center for Wireless Telecommunications (CWT)and SDR Forum

Mark D. Silvius, Terry Brisebois, Chen Chen, Qinqin Chen,Feng Andrew Ge, Bin Le, Paco Garcia Rodriguez,

Tom W. Rondeau, Ying Wang, Alex Young, Charles W. Bostian

#23

2007June 6-8Wireless Personal Communications Symposium

The Challenge• Spectrum Access for First Responders

– A large city experiences a major, crippling earthquake– Total loss of previously existing communication infrastructure– First Responders must stand up a makeshift command post and

establish a temporary communication infrastructure

• Problem– Find available spectrum within a pre-defined band– Rendezvous with an intended receiver– Transmit data over that band with a pre-determined Quality of

Service (QoS) in urban conditions

• System Goals– Mobile and User Friendly– Sense and Classify Environment– Interoperate with other Smart and FRS Radios– Operate in Master-Slave or Infrastructures modes– Adhere to FCC Spectrum Regulations

Proposed Solution “Smart Radio” Design

RF Front End

Tx

Rx

Master Control

Signal Detector

Whitespace Information

Signal Info

Waveforms

Link Control

Decision Making

Source

Sink

Codec

VoiceCSVD

Data

SourceCoding

ChannelCoding

FRS Radio and Smart SDR Signature Database

Status

QoS Desired

Intended Recipient(s)or Channel

Have FRS compliant spectral properties

Dynamically change channels, with no service loss

Must interoperate with legacy FRS users

Ability to dynamically switch QoS settings

Will not produce interference to any other active communications traffic

Operate in a master-slave mode, or infrastructure mode

Source & destination radios must be able to rendezvous

19.2 kbps using 8-PSKRate ½ convolutional channel code

16 kbps using QPSKReed-Solomon channel codingCVSD vocoded voice,

Demonstrate at least 2 QoS settings

Cognitive transceiver25 kHz bandwidth5 MHz FRS Band (462 to 467 MHz)

Have FRS compliant spectral properties

Dynamically change channels, with no service loss

Must interoperate with legacy FRS users

Ability to dynamically switch QoS settings

Will not produce interference to any other active communications traffic

Operate in a master-slave mode, or infrastructure mode

Source & destination radios must be able to rendezvous

19.2 kbps using 8-PSKRate ½ convolutional channel code

16 kbps using QPSKReed-Solomon channel codingCVSD vocoded voice,

Demonstrate at least 2 QoS settings

Cognitive transceiver25 kHz bandwidth5 MHz FRS Band (462 to 467 MHz)

Methodology:– Utilize modular approach for system

conceptualization, design, and implementation

– Primary functions partitioned into smallerself-contained blocks

Table of Requirements

System Block Diagram

RF Front End

• Utilizes the sponsor’s SDR platform for transmit and receive

• Utilizes the SDR platform’s on-board digital filtering capabilities

USRPUSRP Lyrtech SFFLyrtech SFF

Antenna

LNA/Power Amp

Band-passFilter

X

Base-bandMixer

Band-passFilter

WaveformGeneration

= Front End

= Data Source

Antenna

LNA/Power Amp

Band-passFilter

X

Base-bandMixer

Band-passFilter

WaveformGeneration

= Front End

= Data Source

Antenna

LNA Band-passFilter

X

Base-bandMixer

Band-passFilter

WaveformRecovery

= Front End

= Data Sink

Antenna

LNA Band-passFilter

X

Base-bandMixer

Band-passFilter

WaveformRecovery

= Front End

= Data Sink

Hardware Front Ends – Customized for SR and FRS Radio Systems

FRS #1

FRS #2

SR #1 and #2

Signal Detection &Classification (SD&C)

• Characterizes the environment, so that the MC can decide in what vacant frequency ranges to establish a new links– Scans through the authorized frequency range and looks for

unused spectrum to establish a new radio channel

– Searches through the authorized frequency range for actively used spectrum

Spectrum Scanning / Energy Detection SD&C Smart Receiver and Interfaces

FRS Database• FRS database accepts a channel number as input and

generates an XML file that specifies the waveform associated with the channel

• MC block can poll the FRS database for Signal Classification

FRS Database Table FRS Channel Selection

RF WaveformWaveform RepresentationFRS Channel

Selection

RF WaveformWaveform Representation

Master Control (MC)• Dynamically adjusts SDR’s power, frequency, waveform,

CODEC, and QoS configuration settings in real-time

• Directs Spectrum Scanning, Smart Radio Rendezvous, Channel Change Protocol, and maintenance of dynamic data links

MC Module – Waveform Control Rendezvous Beacon Strategy

FRS #1 FRS #2 SR Node #1SR Node #1

SR Node #2SR Node #2

Channel Change Protocol

Ch. A Ch. BMasterNode

CODECS• Transform analog voice waveform into the a digital bit

stream and vice versa using the CSVD format

• Performs Reed-Solomon and ½ Convolutional Channel Coding for digital data streams

• Automatically determine if the input from the user is analog voice signal or a digital data signal

CVSD Decoded Voice WaveformCVSD Encoder Block Diagram

• Faculty Advisor:Dr. Charles W. BostianAlumni Distinguished Professor

bostian@vt.edu, (540)-231-5096

• Team Leader:Mark D. SilviusPh.D. Student

msilvius@vt.edu, (540) 231-2558

• Sponsors:Center for Wireless Telecommunications

http://www.cognitiveradio.wireless.vt.edu/

SDR Forumhttp://www.sdrforum.org/

The Team