phucducnguyen / uvm-fft-ofdm

FFT and Slicing Block for OFDM Communication System

Welcome to the FFT and Slicing Block project for a simple OFDM communications system! This repository contains the design and implementation of a 128-point FFT block and a slicing block, tailored to meet specific OFDM system requirements. Below you will find the detailed specifications, module functionality, and port descriptions.

Project Overview

This project focuses on the development of a critical component for OFDM communication systems. The primary goals are to implement a 128-point FFT and accurately slice the data to extract encoded information. The system adheres to the following specifications:

System Specifications

FFT Size: 128 points (complex)
Frequency Bins:
    Tones are at even-numbered bins 4 to 52.
    Active Tones: 24 tones, each coded as two bits (4 levels) resulting in 48 bits per symbol (one 128-point FFT).
    Fixed Tones: Bins 55 and 57 are used for synchronization and other purposes.
Complex Input:
    The FFT accepts complex inputs from an IQ decoder.
    Each of the 128 points is provided as a pair of complex fixed-point signed 16-bit numbers (1.15 format).
Data Encoding:
    2-bit digital data is mapped to frequency bin data for the IFFT.
    The data encoding levels are:
        00 = 0%
        01 = 33%
        10 = 66%
        11 = 100%
Data Decoding:
    The FFT output converts the complex waveform into frequency bins.
    Each used frequency bin represents 2 bits of output.
    The decoding levels are:
        <25% full scale = 00
        >=25% and <50% full scale = 01
        >=50% and <75% full scale = 10
        >=75% full scale = 11

Module Functionality

The module converts the transmitted complex waveform into a set of frequency bins and slices the data to retrieve the encoded information. The output is produced as bytes, with each FFT block and slicing resulting in 48 bits.

Ports Description

Name	Direction	Bits	Description
Clk	In	1	Positive edge system clock
Reset	In	1	Active high asynchronous reset
PushIn	In	1	Data is present on the input
FirstData	In	1	This is the first data in an FFT block
DinR	In	16	Real part of input (coded 1.15 2’s complement)
DinI	In	16	Imaginary part of input (coded 1.15 2’s complement)
PushOut	Out	1	Data is present on the output
DataOut	Out	48	Output data bits

Getting Started

To clone and run this project, execute the following commands:

git clone https://github.com/phucducnguyen/uvm-fft-ofdm.git
cd uvm-fft-ofdm

Thank you for your interest in the FFT and Slicing Block project for OFDM communication systems!