FPGA-Based Digital Signal Processing Architecture for Real-Time Communication Systems

Abstract

Field-programmable gate arrays (FPGAs) provide a practical platform for real-time digital signal processing (DSP) in communication systems because they combine deterministic timing, fine-grained parallelism, dedicated arithmetic resources, and reconfigurability. This methodology paper proposes a streaming FPGA architecture that integrates digital down conversion, multirate filtering, finite-impulse-response (FIR) channel filtering, fast Fourier transform (FFT)/inverse FFT processing, coordinate rotation digital computer (CORDIC)-based synchronization or equalization, and quadrature amplitude modulation (QAM) mapping/demapping. The methodology emphasizes fixed-point design, pipeline balancing, resource sharing, buffer sizing, and verification against floating-point reference models. A 64-point communication-oriented signal path with 16-bit I/Q samples and an assumed 125 MHz implementation clock is used as the design case. Bit-true numerical tests show an FFT quantization error vector magnitude (EVM) of -71.69 dB and FIR output signal-to-quantization-noise ratio (SQNR) of 91.60 dB, while an initiation interval of one sample per clock provides a theoretical streaming capacity of 125 MS/s. At a 20 MS/s application requirement this corresponds to a 6.25-times throughput margin. These results indicate that a carefully pipelined fixed-point FPGA DSP architecture can meet low-latency real-time communication requirements while retaining flexibility for OFDM, software-defined radio, and broadband baseband processing.