PRODUCTS & TECHNOLOGY
Full Implementation of an OFDM Physical Layer on an FPGA, Reduces Time-to-Market
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An FPGA IP core has been designed as a complete implementation of an orthogonal frequency-division multiplexing (OFDM) physical layer, based on 802.11a/g/n. The core, code named FC300 from Sundance DSP, targets the SMT351T FPGA module with an XC5VSX95T Virtex-5 FPGA from Xilinx, but because the design does not require any resources other than those commonly found in FPGAs it can easily be retargeted to any device family, from Spartan to Virtex-7 to Altera Cyclone or Stratix. Retargeting to different RF hardware is also possible as the VHDL of FC300 assumes only an I/O baseband DAC/ADC interface. FC300 may be used as a reference design to jump start the development of any custom RF application based on 802.11 or other proprietary OFDM data-transmission standard.
When used with the SMT911 RF module, data may be transmitted at up to 54 Mbit/s on any standard 20 MHz-wide channel in the 2.4 GHz ISM or 5 GHz U-NII bands. The core contains both transmit and receive chains and interfaces directly to other DSP or FPGA modules provided by the hardware platform. All 802.11a/g features are supported including data scrambling, forward error-correction via convolutional encoding at rates from ½ to ¾, sub-channel coding of BPSK, QPSK, 16 QAM or 6 4QAM, both short- and long-training sequences, pilot insertion, and the IFFT/FFT required to convert to/from time-domain RF I/Q signals. The receiver logic includes estimators for center-frequency offset and fractional-sample symbol timing as well as independent per-sub-channel gain & phase compensation. The SMT911 supports 1x1 SISO and 2x2 MIMO on a single module.
FC300 may be used with a variety of RF/DSP/FPGA hardware modules available from Sundance DSP; different configurations may easily be created using the 3L Diamond development environment. FC300 is targeted at the enterprise networking, telecom transmission and switching, storage and high-end military and defense communication systems.