The FPGA boards are the work horses of the RRH and are responsible for the waveform processing. These FPGA boards are custom designed from scratch in this project and has various interfaces and FPGAs as per the requirements. Most of these boards feature very high speed interfaces (100G, 40G), radio interfaces and power interconnects. The in-house design of these boards provided us the means to tailor the requirements, form factors of these boards.
FPGA board is like the brain of the Remote Radio Head( RRH). FPGA boards perform all the logical and computational operations.
Operations like digital beamforming, digital-to-analog and analog-to-digital conversions are done. These boards are interfaced between the Base Band unit(BBU) and Analog Front End(AFE) broad through optical cable and RF cable respectively.
Separate FPGA boards are designed for FR1 (MIMO) and FR2 (mmWave)range. High end FPGAs and ICs are used.
The PCB board is manufactured and assembled with high precision and each PCB board is about 18-layers.
Clear knowledge on digital circuits is required to design the board. High end software tools are used for schematic, layout and simulation purposes.