Low Power Area Optimum Configurable 160 to 2560 Subcarrier Orthogonal Frequency Division Multiplexing Modulator-Demodulator Architecture based on Systolic Array and Distributive Arithmetic Look-Up Table

Abstract

In this work, configurable and reusable Dual-Tree Complex Wavelet Transform (DTCWT) Orthogonal Frequency Division Multiplexing (OFDM) modulator-demodulator based on Optimum Systolic Array (OSA) and Modified Distributive Arithmetic (MDA) algorithm is designed for low power underwater MODEM applications. The DTCWT-Inverse Dual-Tree Complex Wavelet Transform (IDTCWT) filters are designed considering integer 10-tap Q shift filter coefficients that are quantized and rounded off to achieve symmetry among filter coefficients. Multi stage DTCWT structure is used to perform 2560 subcarrier modulation and demodulation using MDA and OSA modules. The OSA structure is designed with optimum placement of Processing Elements (PE) and the MDA structure is designed to compute two filter outputs per module with Look-Up Table (LUT) of depth 8. The 2560 modulation is carried out using folded pipelined structure that comprises of two fold and four fold configurable modules. The reusable pipelined folded OFDM modulator-demodulator is implemented on Virtex-5 FPGA and operates at a maximum frequency of 248 MHz occupying less than 15% of FPGA resources and consumes less than 1.33 W power.