Developing a SDR Testbed Alex Dolan Mohammad Khan Ahmet Unsal Project Advisor Dr. Aditya Ramamoorthy

Presentation Overview Background Information Project Overview System Design Progress and Plan

Background Information Software Defined Radio USRP-2 DaughterBoard

Project Overview Project Goal 1.Develop a Software Defined Radio network testbed, using MATLAB Simulink and USRP-2 2.Evaluate MATLAB Simulink’s Versatility as a SDR platform

Requirements Implement a SDR Testbed Use of Universal Software Radio Peripheral-2 (USRP-2) Use of MATLAB Simulink Implement digital modulation schemes like FSK, BPSK, DBPSK, QAM Implement simplified MAC

Constraints USRP-2 o Number of nodes o Frequency Range o Bandwidth o Transmission Power Processing o CPU Cycles Time

Assumptions Tested under reasonable conditions Normal level of noise Controlled transmission range

Resources 2 USRP-2s o Sample rate of 100 MHz 2 Dell Optiplex 980 Computers o Intel Core i7 Processor Daughterboards o Various daughterboards for different frequency bands o Able to transmit and receive up to 5 GHz

Design Process Design Physical Layer Design MAC Layer Testing and Logging

System Decomposition Physical layer: –USRP-2 –Simulink – DSP and digital communications MAC: –Coordinates t ransmission among nodes. Testing and Logging: –The tools used to test the system. –Tracks progress and success.

System Block Diagram Testing & Logging MAC PHY RF Daughterboard (USRP2) Rx / Tx

Physical Layer Simulink signal processing FSK, PSK, QAM modulation/demodulation Synchronization and packetization Error control USRP-2 hardware Ethernet interface with 100 MSamples/s A/D conversion

Physical Layer (PHY) Block Diagram Rx USRP-2 Variable f 0 and f s Down conversion Digital Signal Processing Filtering Synchronization Demodulation Error control etc. Data Digital Signal Processing Modulation Filtering Error control encoding etc. Tx USRP2 Variable f 0 and f s Up conversion

MAC Layer Coordinate channel access between nodes Simplified implementation Carrier sense multiple access with collision avoidance (CSMA/CA) Written in C++ or embedded MATLAB.

MAC Design a MAC that allows simultaneous transmissions when both interfered messages can be decoded Distributed Algorithm o Similar to distributed coordinate function o Use RTS and CTS messages to coordinate interfering transmissions

Testing and Logging Select logging/testing options Logging data to file from individual layers/components Scopes/Visualization of data from individual layers/components Generation of statistics Validation

Testing Procedure Design Physical Layer in Simulink. Design each component in Simulink. Test in controlled MATLAB environment. Test using USRP-2 and Simulink. Introduce MAC layer Move from point to point and introduce more nodes. Compare results to simulations and expected results. Observe BER, data rates, etc.

Schedule

Questions?