Working with programmable radios Hariharan Rahul

Our Group’s Experience USRP USRP2 WiGLAN WARP Lyrtech

What have we used programmable radios for? Network-oriented PHY design – Flexible layering SOFT, MIXIT, Softcast – New technologies: UWB, MIMO SWIFT, FARA, IAC – Dealing with Interference ANC, ZigZag

Peeling the Onion Changing the PHY interface – Soft information Changing the PHY algorithms – Interference cancellation and Interference alignment Timing-sensitive PHY algorithms – Adaptive sensing Bandwidth limited – Wide frequency bands Host FPGA

USRP and USRP 2 What’s good? – Affordable – Stable algorithms – Large community – Easy to use – USRP had narrow bandwidth; better with USRP2 What’s bad? – No room for additional FPGA logic – Bandwidth only up to 20 MHz even in USRP2 – High latency

WARP What’s good? – Close to our ideal board – Large FPGA – Relatively fast host interface – Rich development platform Onboard processor cores What’s bad? – Cost – Relatively narrow bandwidth (FPGA code does 10 MHz, radio can support 40 MHz) – Calibration

WiGLAN What’s good? – Very high bandwidth (128 MHz) – Large FPGA to deal with high bandwidth – Calibrated What’s bad? – Development process Form factor – Out of print

Learnt Lessons A programmable radio is a package – Hardware – Software SNR-BER curve is the proof of the pudding