The platform allows basestation OEMs to use PAs to reduce the operating power in the radio head. It permits developers to quickly tune the system for optimum efficiency. This is said to save cost as the PA and transceiver stage consume approximately 40-60% of the basestation's total cost. It offers OEMs the flexibility to quickly adapt to changes in specification or air interfaces.

 

The platform includes a specially designed board containing RF preamps, ADCs, DACs, a Xilinx Virtex-II Pro FPGA to provide interface support for CPRI, OBSAI and digital I/Q connectivity and a Xilinx Virtex-4 SX55 FPGA for implementing digital radio signal processing functions, and an operating system for control of the board via Ethernet connection.

 

The board has two transmit and two receive paths, plus two additional receive paths for digital pre-distortion (DPD), and it can support any 20MHz spectrum in the 400MHz to 4GHz frequency range. It's capable of driving the PA from 2-40W, while providing an effective receiver noise figure per path of 3dB. The user can set up and control the board using a graphical user interface that enables key signal processing parameters to be displayed and adjusted quickly and easily.

 

The platform integrates digital up conversion (DUC), digital down conversion (DDC) and crest factor reduction (CFR) functions from Xilinx, providing an output peak to average power ratio (PAPR) of only 5.60dB for W-CDMA and a reduction of up to 1.57dB for WiMAX radios. The Xilinx W-CDMA DFE includes a 3 carrier DUC, 3 carrier CFR and 6 carrier DDC. It provides ~2.5W of dynamic power consumption, while consuming only 55% DSP48 usage in a Virtex-4 SX25 FPGA. The Xilinx WiMAX DFE offers DUC/DDC support for 3.5/7MHz channels (IEEE802.16-2004) and 5/10 MHz channels (IEEE802.16-2005); CFR and AGC are also supported. The WiMAX DFE is designed to work in UMTS clock subsystem frequencies and only consumes 39% DSP48 usage in a Virtex-4 SX25, for a 1x1 configuration. The CDRSX development platform is available now from AXIS and is priced at US $34,995.