SDR_Matlab_OFDM_802.11a

This simple OFDM demo is based on IEEE 802.11a OFDM format for testing SDR hardware.

Using Software Designed Radio (SDR) to transmit OFDM signals at 5 GHz.

Transmitter and Receiver hardware : Zedboard (Xilinx Zynq®-7000) + AD9361 (Analog Device-FMCOMMS3)

Software needed :

• Matlab R2016a
• support package for Xilinx Zynq-Based Radio (R2016a version)

Before executing this code, please follow this tutorial to install support package for Xilinx Zynq-Based Radio in Matlab.

Code Structure :

Please open multiple Matlab windows to run Hardware_TX.m and Hardware_RX.m respectively.

Hardware_TX.m

TX_signal.mat

OFDM_TX.m

• data_Payload_1.mat
• data_Payload_2.mat
• oversamp.m

Hardware_RX.m

OFDM_RX.m

• Long_preamble_slot_Frequency.mat
• setstate0.m

RX_test

• RX.mat
• RX2.mat

GUI :

• GUI_TX

• GUI_RX

Video Demo : https://www.youtube.com/watch?v=gNmMxtsWckw

System Model :

OFDM Block Diagram

Code Function :

Implemented

• Data Signal Mapping
• Packet Detection
• Coarse/Fine Frequency Offset Estimation & Compensation
• Channel Estimation & One-Tap Equalizer
• Data De-Mapping

Not implemented yet

• AGC (Auto Gain Control)
• Fine Symbol Timing Estimation
• Convolutional Decoding
• De-Interleaving
• Frame check calculation (It assumes every packet is the same length)

TX System Model

• Short Preamble

• Long Preamble

• Payload

• TX signal

TX RX Hardware Parameters

The way to change Hardware IP / Mac address

Edit newip.sh file in SD card

# Flush existing config
ip addr flush dev eth0
ip link set dev eth0 down
# Set up new config
ip addr add 192.168.3.3/24 dev eth0
ip link set eth0 address 00:0A:35:00:01:23
ip route add default via 192.168.3.1
ip link set dev eth0 up

Then, use router DHCP hand setting mode to distribute network configuration parameters :

RX System Model

• "Delay and Correlate" algorithm for Packet Detection

• Packet Detection (normal case) , Threshold=0.75

• Packet Detection (problem case & deselect the imperfect packet)

• Coarse CFO Estimation & Compensation

• Fine CFO Estimation & Compensation

• Channel Estimation & Equalizer