June, 1999©Vanu, Inc. Vanu Bose Vanu, Inc. Programming the Physical Layer in Wireless Networks

June, 1999©Vanu, Inc. Hardware Radio –Separate devices for separate functions Software Radio –One device for many functions AMPS GSM TV Garage Door The Goal

June, 1999©Vanu, Inc. Software Radio Phase Space Source: Joe Mitola

June, 1999©Vanu, Inc. Virtual Radio Architecture Wideband IF sampled at 33 MSPS GuPPI I/O OS SpectrumWare OS extension PC User Interface Wideband Down Converter A/D Daughter card Application AMPS

June, 1999©Vanu, Inc. I/O System Performance GuPPI device driver –Use virtual memory re-mapping to eliminate expensive data copies –Use memory to absorb process scheduling variance Current performance –Sustained transfer of 512 Mbits/sec (32 16 bits) between application and RF front end –Low processing overhead: < 0.1 cycles/sample

June, 1999©Vanu, Inc. Programming Environment Architecture –Data Pull facilitates lazy evaluation –Object Oriented Environment code reuse, simple implementation –Stream Abstraction simplifies implementation of signal processing algorithms SourceSink ProcessingData Stream Control

June, 1999©Vanu, Inc. Design Evaluation Flexibility –Modular system can be re-programmed to use any multiple access, modulation, coding etc. On-the-fly modifications, incremental upgrades –Well supported by programming environment System wide optimization –Shared computational resource Ease of use –~600 lines of code per radio system –up to 90% code re-use for some applications Portability –Runs on Pentium and Alpha, porting to strongARM

June, 1999©Vanu, Inc. AMPS Cellular Receiver Source Audio Filter Sink Quadrature Demod. Channel Filter 400 Tap % CPU PII/ % 4 %1 % 2 % 33M40K 8K Samples/ Second

June, 1999©Vanu, Inc. Application to Wireless Networks Universal roaming –can interoperate with any LAN/MAN/WAN/Cellular Better use of Spectrum –adapt to environmental, traffic and user demands Technology Tracking –New standards are simpy software upgrades Ad-Hoc Networking –Not limited to using one physical layer –Dynamically compile the best radio for the situation QoS mechanisms –modify coding, bandwidth, modualtion

June, 1999©Vanu, Inc. Programming Model Physical Data link Link Framing bits symbols Discrete signal Continuous signal Channel Coding Line Coding Modulation Multiple Access A/D Conversion Frequency Conv. OSI Layers Virtual Radio Layers Software Hardware MAC bits

June, 1999©Vanu, Inc. Ongoing Research Adaptive Algorithms –Mapping of requirements to layers –Channel monitoring –Protocols for negotiating adaptations Software Downloads –Protocols for downloading new capabilities Need incremental downloads Processing Platforms –Handheld strongARM port –Basestation/Infrastructure distributed real-time cluster