Integration of System Design and Standard Development in Digital Communication Education

Xiaohua(Edward) Li

State University of New York at Binghamton

Contents

Introduction SAM project in digital communications Technical standard of SAM Conclusions

Introduction

Digital communications education should teach theory with a systematic view use MATLAB projects to strengthen the

systematic view develop practical system design experience

Traditional ways of teaching may not perform well enough

Introduction

Our approach: joint theory, system design and technical standard drafting

Objectives: Integrate theory with hands-on experience Cost effective: computers only Convenient: Matlab programming only Competitive: drafting standards

Design of the SAM Project

SAM: soft acoustic modem a modem with PC and MATLAB

Overview: Phase 1: baseband transmission Phase 2: passband transmission (wireline) Phase 3: passband with coding (wireless) Modem standard discussion and draft

Work of students demonstration, presentation, standard draft

The SAM Project (1)

Phase I. Baseband system design Theory: data packet, pulse shaping, synchronizations Hardware: one PC Software: MATLAB

The SAM Project (2)

Phase II. Passband wired transmission Theory: modulation/demodulation, synchronization Hardware: one or two PC Software: MATLAB

The SAM Project (3)

Phase III. Wireless modem Theory: wireless, SNR, channel coding/decoding

Hardware: two PCs

Encoder S1

S2

reg 0 reg 1 reg 2

XOR00

10

01

S1,2

S3,4..

.

...

.

...

S1,2

S3,4

S1,2

S3,4

S1,2

S3,4

S1,2

S3,4

S1,2

S3,4

S1,2

S3,4

.

.

S1,2

S3,4

S1,2

S3,4

00

10

1000

0111

11

The SAM (4). Software: MATLAB

The SAM Project (5)

Typical transmitter and receiver block diagrams

Simulation results of one student group

Start Transmitter Generate random

message

Format message with Barker and

Training SequenceConvolutional encode

messageDifferentially

encode entire signal

Pulse shape entire signal

Transmit Modulate signal with

1 kHz carrier

Sample for 1 kHz carrier

Record Waveform upon detection of 1 kHz carrier signal

Demodulate signal

Differentially decode

Time synchronize and sample

Frame Synchronize using Barker

Convolutional decodeAssess Bit Error

Technical Standard Activity

Technical standard Provide design guide and inter-operability Encourage competition

Approaches for drafting standards: Only design objective is assigned Students are free to choose techniques Perform regular discussion to define common

parameters Each group draft a standard, among which

the most competitive one is recommended

Conclusions

Project that stimulates students’ interest Use practical design projects which involve

both software and hardware Use tools which are under students’ control Introduce competitions Make it challenging by leaving questions open Draft standards instead of writing ordinary

reports