Connecting Theory and Practice

Spring 2013Mid Presentation

TechnionIsrael Institute of Technology

Supervisors:

Rolf Hilgendorf, Debby Cohen

Consultant:

Eli Shoshan

Students: Etgar Israeli, Shahar Tsiper

Theory

Project Definition and Goals

Project Main Stages:

◦ Matlab Reconstruction

◦ AWR Activities – Part A

◦ AWR Activities – Part B

◦ A-Matrix Calibration

◦ MWC Development Support Systems

Epilogue

Contents

Multiband model:• N – max number of transmissions• B – max bandwidth of each transmission

Goal: Blind detection + Recovery

Minimal achievable rate: 2NB << fNYQ

Model

~ ~~~

1

2 sT

Input Block Diagram

sequencesm

q

1

2 sT

snT

snT/ ( )m qp t

Expander

m

sequences

[ ]my npf

Δ

Analog Card Digital Processing

s

p

fq

f

Support Recovery + Reconstruction

• Support S recovery• Signal reconstruction

Sz f

~~~~

z f

SA

y f

A

S Sz f A y f †

Output Block Diagramm sequences

[ ]my n

SupportRecovery

Reconstructor

Sz f

SA

~~~~

z f

~~~~

z f

A

S Sz f A y f †

Digital Processing

The Mixing Series Pi(t)

In theory there is a solid algorithm for building the A-Matrix. We use the fourier coefficients of the mixing series:

We’re interested in finding the coeff. Therefore we’ll use:

We can further simplify if the mixing series are step functions:

Building the A-Matrix

ilc

We can now define an all constant A-Matrix:

We can now use the same A matrix in time domain. Due to the invariance for iDTFT.

Building the A-Matrix – cont.

After the Support Recovery process:

Using Moore-Penrose psuedo-inverse process for the matrix:

Solving the problem:

Support Recovery for the A-Matrix

, 2m mS

rL r N

AA

Matlab reconstruction algorithm

AWR Activities

A-matrix Calibration

MWC development support systems

(Labview programming Rolf/Idan)

Project Work Plan

Understanding and fixing the Matlab code

Learning AWR tool and Modeling MWC

Deeper understanding of the main issues the

system suffers from

Developing calibration solutions for the system

Implementing the solutions on the actual system

Main Challenges

◦ Matlab Reconstruction

◦ AWR Activities – Part A

◦ AWR Activities – Part B

◦ A-Matrix Calibration

◦ MWC Development Support Systems

Project Main Stages

We’ve developed signal comparison

algorithm using cross-correlation.

Main Issues:

◦ Support recovery is successful at approx. 80% of

the runs (better % for qpsk than sinc)

◦ If the recovery adds redundant harmonics

◦ If time reconstruction still isn’t perfect

Matlab Reconstruction

Understand schematics of analog part of

new MWC

Get understanding of AWR tool

Define method for input and output files

◦Matlab , CSV etc.

Enter first draft of MWC schematic

AWR - Part A

Current Front-End + Series Generator

Refine MWC design

◦ Get final spice models for all components

◦ Get model of card

◦ Enter final schematic

◦ Ensure synchronization between patterns

◦ Ensure synchronization with trigger

◦ How to create the input scenarios (AWR or matlab)

◦ Sampling rate for AWR simulation and for output

Basic Verification of output data using matlab

◦ Is input mapped to output as expected

◦ Limits for input signal (saturation, undetectable due to noise)

◦ Anti-aliasing filter response

AWR - Part B

Full Current System Setup

Understanding the Physical Issues

Using the AWR model output define A-

Matrix

◦ Perform developed procedure using model and

matlab only

◦ Perform procedure using MWC development

systems described below

A Matrix Calibration

Phase Shifts inside the system:

◦ Signals enter with unknown phase into the analog card. We should make

sure we know how to recover the signals with their original phases.

◦ Analog Low-Pass Filter causes unknown phase shifts between the

different channels.

◦ Fixed phase shift between the mixer channels and the Expander Unit.

Noise Sources:

◦ Impedance mismatches in the input cable end – attenuator is used, and

acts as a noise source.

◦ Analog splitter before entering the different mixers provide as a noise

source.

◦ Analog Low-Pass Filter causes noise.

Main Physical Issues

Modeling each part of the system

independently, according to schematic

Trying to develop specific solutions to each

of the micro-problems

Proposed Solutions – First Approach

1

2 sT

Main Physical Issues

sequencesq

m

1

2 sT

snT

snT/ ( )m qp t

Expander

m

sequences

[ ]my npf

Δ

Analog Card

Digital Processing

ATT

Unknown phase

Splitter Noise

Attenuator Noise

LPF – Noise & phase shift

Phase shift

Unknown?

Multiplying by a correction matrix before applying the

original A-Matrix - .

◦ In order to get we planned to drive an impulse function into the

system, and determine the impulse response for each Hardware

Channel

Applying a filter after multiplying the signal with the A-

Matrix -

◦ We’ll use multiple known fixed carriers inputs (modulated sincs

or simple sine waves) in order to devise the required

Second Approach – 2 Main Stages

Thinking on new calibration methods after

examining a full analog model or real MWC

System - Still work in progress

Synchronizing the A matrix’s via cyclic shifts

to the mixer series - Might be necessary

Current Approach

Data acquisition using NI converter with

external sampling clock

Immediate system based on Tabor AWG

◦ Load data from AWR simulation

Final development system using NI AWG

◦ NI sync card and external clocking

MWC Development Support Systems

Matlab:

◦ Used for full modeling of the MWC system –

Already given – need to be fixed

◦ Calibration Methods

AWR:

◦ Implementing an analog model of the entire

MWC system.

◦ Linking the analog AWR frontend and the

digital Matlab backend

Labview:

◦ Implementing calibration procedure

Systems Used In Project

Main missions week1 2/6 week2 9/6 week3 16/6 week4 23/6 week5 30/6 week6 7/7 week7 14/7

Fix Matlab reconstruction algorithm

Understanding the existing Matlab code and Sub-Nyquist Radar AWR

Becoming proficient in AWR environment

Understand schematics of analog part of new MWC

Define method for the input and output betweem AWR amd Matlab

Enter first draft of MWC schematic

Entering second stage of project: Refine MWC design

Project Gantt - 1st Stage

Thank You!

Spring 2013Mid Presentation

Supervisors: Rolf Hilgendorf, Debby CohenStudents: Etgar Israeli, Shahar Tsiper

TechnionIsrael Institute of

Technology