High price (~ $ 3,000). â« Legal limitations on the use of radio transmitters. â« Form factor not convenient for some applications. â« Example: NI USRP ...
Software-Defined Radio in MATLAB/Simulink with RTL-SDR Hardware Alexander Sergienko Saint Petersburg Electrotechnical University “LETI” Department of Theoretical Fundamentals of Radio Engineering
ICCTPEA-2014, St. Petersburg, June 30 – July 4, 2014
Software-Defined Radio Concept Ultimate dream Analog-to-Digital Converter
Software
Antenna ..., 0, 1, 0, 0, 1, 0, 1, 1, ...
Current reality Analog-to-Digital Converter Antenna
Analog Processing (Filtering, Frequency Conversion, etc.)
Software
Professional SDR Hardware Good performance High price (~ $ 3,000) Legal limitations on the
use of radio transmitters Form factor not convenient for some applications Example: NI USRP
Realtek RTL2832U Demodulator Released by Realtek in 2010 Main function: demodulation of digital
television signals (DVB-T standard) SDR mode: officially intended for reception of FM broadcasting and DAB (demodulation performed in software by device drivers) Since 2012, widely used by radio amateurs as a cheap SDR-platform “RTL-SDR” Retail price: from $7
Exterior of RTL-SDR devices
RTL-SDR: basic parameters ADC resolution: 8 bits Sampling rate: up to 3,2 MHz Frequency range is defined by tuner chip:
Widest range: Elonics E4000
52B1100 and 1200B2200 MHz
Mostly used now: Rafael Micro R820T
24B1766 MHz
Drivers exist for all major operating systems:
Windows, Linux, Mac OS, Android
MATLAB/Simulink Support Introduced by MathWorks in January 2014 Support package available for download from
the MathWorks site System requirements:
MATLAB R2013b or later
Simulink support:
Block RTL-SDR Receiver
MATLAB support:
System object comm.SDRRTLReceiver
Support by Simulink USB port number Carrier frequency Gain Sampling rate Frequency correction Turn on “Lost samples” output port Turn on “Latency” output port Output data type Number of samples per frame
Support by MATLAB >> h = comm.SDRRTLReceiver
>> S = info(h)
h =
S =
System: comm.SDRRTLReceiver Properties: RadioAddress: CenterFrequency: EnableTunerAGC: SampleRate: OutputDataType: SamplesPerFrame: FrequencyCorrection:
'0' 102500000 true 250000 'int16' 1024 0
The following values show radio settings, not the property values of RTL-SDR receiver System object. For more information, type 'help comm.SDRRTLReceiver'. RadioName: RadioAddress: TunerName: Manufacturer: Product: GainValues: RTLCrystalFrequency: TunerCrystalFrequency: SamplingMode: OffsetTuning: CenterFrequency: SampleRate: FrequencyCorrection:
'Terratec T Stick PLUS' '0' 'E4000' 'Realtek' 'RTL2838UHIDIR' [1x14 double] 28800000 28800000 'Quadrature' 'Disabled' 102500000 250000 0
MATLAB/Simulink Examples List of examples:
Spectral Analysis Frequency Offset Calibration FM Monophonic Receiver FM Stereo Receiver FRS/GMRS Receiver
Every example is implemented in two forms:
Simulink model MATLAB script
FM Broadcasting Signals Spectrogram, center frequency 91,0 MHz
GSM Signals Signal Fading
25
Signal Magnitude
20
15
10
5
0
0
0.1
0.2
0.3
0.4
0.5
0.6
Time, seconds
0.7
0.8
0.9
1
DVB-T2 Signals 1
1
0.9
0.9
0.8
0.8
0.7
0.7
Нормированная Normalized КФ CF
Нормированная CF КФ Normalized
Correlation function
0.6 0.5 0.4 0.3
0.5 0.4 0.3
0.2
X: 2.188 Y: 0.1234
0.2 X: 3.584 Y: 0.05783
0.1 0 -1
0.6
-0.5
0
0.5
1
1.5 t, мс
2
2.5
3
3.5
0.1 4
0 -20
-15
-10
t, ms
OFDM Symbol Duration (3,584 ms)
X: 6.25 Y: 0.122
Multipath Nature of Impulse Response
-5
0 , мкс τt, µs
5
10
15
20
Possible Signals to Process Identification beacons on vessels (AIS) and
planes (ADS-B) 430 MHz devices (wireless sensors, car remote controls, etc.) Weather information from satellites GNSS (GPS, GLONASS) (External amplifier required) Radio astronomy signals (External amplifier required)
Educational Use: UC Berkeley, DSP Course
Conclusion Combination of RTL-SDR USB hardware and
MATLAB/Simulink software can serve as a cheap SDR platform for educational purposes: Lecture demonstrations Laboratory assignments Course projects Promotion of technical creativity, popularization of wireless engineering, etc.
