31-07-2012, 04:16 PM
Punctured Convolutional Coding Scheme for Multi-Carrier Multi-
Antenna Wireless System
Punctured Convolutional.pdf (Size: 414.3 KB / Downloads: 149)
INTRODUCTION
MOTIVATION
The work presented here is to begin to think about ways for future wireless
communication systems to thrive with the growing shortage of signal bandwidth. Are
there ways for existing wireless systems to share and use a common bandwidth
efficiently and without interference among each other? Bandwidth for today’s wireless
technology is at a premium, and in some cases is the bottleneck in delivering high data
rate services to people worldwide. The overall theme of this research is to create a
framework that consists of complex wireless systems that demonstrate the gain from
Multiple Element Array (MEA) algorithms to provide high data rates at high bandwidth
efficiency.
RESEARCH GOAL
A system level simulation and analysis on the effects of a variable rate error correction
technique. The simulation blocks should be modular in design so that they can be used in
conjunction with other blocks to create any advanced digital communication system. The
wireless systems created here use MEA algorithm techniques [1]. The system is
decomposed into key building blocks. Each block is represented as a floating-point
model then as a fixed-point model. The floating-point model simulates the optimal
functionality of the system. The fixed-point model is functional equivalent to the
floating-point model and should model the bit level accuracy of the model. A logic
equivalency between the fixed-point model and behavioral VHDL is determined which in
turn is used in a rapid design flow SSHAFT [2] process to generate actual chip design.
THESIS ORGANISATION
There are 5 chapters to this report. Chapter 2 presents the framework that the proposed
error correction scheme is meant for. The theory behind the specific blocks making up
the proposed scheme is discussed in Chapter 3. Chapter 4 discusses the floating-point
and fixed-point SIMULINK implementation and issues involving hardware
implementation. Also, discussed is the hardware implementation of the Viterbi decoder
design in MODULE COMPILERÔ. A summary of the project and a discussion of possible
future work are discussed in Chapter 5.
THE MCMA FARME WORK
This chapter provides a description of the Multiple-Carrier Multiple-Antenna (MCMA)
framework. The framework is meant to build advanced next generation communication
algorithms for wireless Local Area Networks (LAN’s) applications. The idea is to
provide a general framework to allow the creation of (MCMA) systems at a high level of
abstraction from a consortium of building blocks. The blocks are designed in SIMULINK
and should be modular in design and “flexible” enough so that major parameters can be
changed with relative ease. SIMULINK allows for this type of design, it gives systems
designers the flexibility to build different algorithm blocks and build a variety of complex
systems to meet a vast array of system applications. This section details the
specifications for such a system.
CONCLUSION
The MCMA framework is to describe sophisticated digital communication algorithms
that exploit diversity in three dimensions: time, frequency, and space. “The Hornet
proposal:” by [3] was the first attempt to capture the formulation of this framework at a
simulation level. The work here was to create a flexible error correction scheme that can
be used in a variety of complex system simulations. A floating-point and fixed-point
adaptive punctured convolutional coding scheme has been introduced with code rates of
1/2, 2/3, 3/4, and 7/8. A parameterable parallel Viterbi decoder design in MODULE
COMPILER has also been designed. The decoder is a design example to show how the
MCMA framework integrates with SSHAFT design flow.