**Series in
Signal and Information Processing, Vol. 21
edited by Hans-Andrea Loeliger**

Murti V.R.S. Devarakonda,

**Joint Matched Filtering, Decoding, and Timing
Synchronization**

1. Auflage/1^{st} edition
2012, XVI, 156 Seiten/pages, € 64,00.

ISBN 3-86628-415-4, 978-3-86628-417-3

This thesis is motivated by the success of analog decoder
implementations

using message passing algorithms and explores ideas for all-analog receiver
architectures. Current analog implementations are limited mainly to the decoder
because receivers require a majority of tasks, such as matched filtering, symbol
synchronization, and equalization, performed in the digital domain. A discrete-time interface is required between an
analog decoder and the rest of the receiver, necessitating elaborate control
circuitry to be developed.

In the current thesis, we aim to develop a system that combines detection,
decoding, and symbol synchronization into one. Our focus is on choice of
algorithms that can be implemented in the form of a ``clockless''
circuit. In particular, we study whether it is feasible to push symbol
synchronization to the end of the receiver processing chain and eliminate
discrete-time interfaces throughout.

To achieve this, we first develop message passing algorithms for detecting
pulses, and show that a matched for a pulse can be implemented by forward-only
message passing on a Forney-style factor graph. We introduce the notion of a **glue factor** and show how likelihoods
for various hypotheses involving state space models can be computed.

Second, we introduce the notion of an **input-tracking
decoder**. We make use of a few concepts from dynamical systems to derive a
decoder for a binary code that works with continuously varying inputs and
produces continuously decoded outputs.

We combine these two ideas in the end to discuss two receivers, each of which
performs joint detection, decoding, and symbol synchronization.

In one receiver, the discrete-time interface between demodulator and decoder is
eliminated and in another, it was shown that near-optimum timing
synchronization can be obtained with the forward processing approach. The ideas proposed and the two receiver
architectures differ in many ways from conventional solutions. The thesis is
concluded with suggestions on variant architectures and further work that is
required to explore algorithms on similar lines.

**Keywords**: Demodulation; Detection; Input-tracking decoding; Timing
synchronization; Factor graphs; Graphical models; Message passing; Analog receivers.

Direkt bestellen bei / to order directly from: Hartung.Gorre@t-online.de

Reihe "Series
in Signal and Information Processing" im Hartung-Gorre Verlag

**Hartung-Gorre Verlag / D-78465
Konstanz / Germany**

Telefon: +49
(0) 7533 97227 Telefax: +49 (0) 7533
97228

**http://www.hartung-gorre.de** eMail: **verlag@hartung-gorre.de**