A Testbed for Rapid Prototyping

Abstract

We are presenting a platform for rapid prototyping of wireless communication systems. Signal processing and (de)coding are done completely in software on a Cell processor. Protocol stacks are implemented on an IXP2350 network processor. Implemented functionality includes advanced MIMO-OFDMA receiver algorithms as well as a protocol stack for adaptive multi-user transmission.

Benefits of the SDR Platform

• Maximum flexibility for standard evolution and multi-standard receivers
• Reduced development time
• Standard components

Platform description

The Cell processor consists of a Power architecture core (running a Linux kernel), and eight coprocessors optimized for single-precision floating point arithmetic.  With up to 180 GFLOP/s it offers considerably higher computational power than currently available DSPs.

The IXP2350 network processor contains an XScale core (running a Linux kernel) and four hyper-threaded microengines optimized for packet processing. The microengines are capable of handling up to 2.5 GBit/s data plane traffic; control and management plane are implemented on the XScale.

The interface to the radio frequency frontend is implemented in a Virtex5 FPGA and memory mapped into the PCIe address space. The system contains several direct memory access (DMA) controllers, which are used to improve bus utilization. Via this interface, the Cell and the FPGA exchange base band time domain sample streams. Digital upand downconversion is performed in the FPGA. Bus options for RF frontend connection include PCIe-over-cable, USB2, Ethernet and proprietary LVDS signalling.

Acknowledgments

This work is supported in part by the Federal Ministry of Department Broadband Mobile Communication Educational and Research (BMBF) under grant 01BU0652.

References

• A. Ibing, D. Kühling, D. Wieruch, H. Boche, "Software defined hybrid MMSE/QRD-M Turbo receiver for LTE-Advanced uplink on a Cell processor", in ICC 2009
• A. Ibing, D. Kühling, M. Kuszak, C. Helmolt, V. Jungnickel, "Flexible demonstrator platform for cooperative joint  transmission and detection in next generation wireless MIMO-OFDM networks", Tridentcom 2008
• C. Holmes, A. Ibing, D. Kühling, "On network processor based protocol stack implementation for 4G base stations", in WTS 2009 MIMO-OFDM networks, A. Ibing, D. Kühling; in WTS 2009