LONDON — Xilinx Inc. is demonstrating a digital pre-distortion (DPD) based reference design based on its Virtex range of FPGAs and XtremeDSPs that is optimized for Freescale Semiconductor's LDMOS power amplifiers at this week's World Mobile Congress in Barcelona, Spain.
The companies say the deisgn could significantly reduce development time and both capital and operational expenditure of wireless infrastructure.
The reference design, which will be released in April, is targeted at developers of LTE, WiMAX, WCDMA and TD-SCDMA multi-carrier systems and complements existing front end reference designs available from Xilinx.
“Digital predistortion has become a very important way to increase the linear efficiency of power amplifiers,” notes Giles Peckham, marketing manager for major communications accounts in the wireless infrastructure group at Xillinx.”It is a complex task and others have implemented versions of the solution, but not to the level of optimization that we are able to show with this reference design that has been validated with Freescale's RF LDMOS power amplifiers.”
He adds the flexible and scalable FPGA implementation will be available as a product during the first half of this year, and that the company has been developing other versions that use DPD for Gallium Nitride and GaAs based power amplifiers
Power Amplifiers account for a significant portion of a base station's operating expenditure due to their lack of efficiency with complex signals. Digital pre-distortion can improve efficiency and reduce cost. T
The technique preconditions the signal entering the amplifier to compensate the non-linear transfer characteristics of the power amplifiers, resulting in a more linear, higher output power radio. Alternatively, the technique allows the system designer to choose a smaller output stage if desired, saving both cost and power.
Packham suggests the Xilinx design design requires less than a quarter of the available slices and a third of the memory resources in the smallest DSP optimized Virtex-4 SX device, providing system designers the lowest cost and power and the most flexible and adaptable solution in the market today.