/pdf/statistical-theory-of-communication-4wy4yg9ato.pdf

Statistical Theory of Communication

We discuss the use of a coherent digital receiver for the compensation of linear transmission impairments and polarization demultiplexing in a transmission system compatible with a future 100-Gb/s Ethernet standard. We present experimental results on the transmission performance of 111 Gbit/s POLMUX-RZ-DQPSK. For a dense WDM setup with channels carrying 111 Gbit/s with a 50 GHz channel spacing (2.0 bits/s/Hz), we show the feasibility of 2375 km transmission. This is enabled through coherent detection which results in excellent noise performance, and subsequent electronic equalization which provides the high tolerance to polarization mode dispersion and chromatic dispersion (CD). Furthermore, we discuss the impact of sampling and digital signal processing with either 1 or 2 samples/bit. We show that when combined with low-pass electrical filtering, 1 sample/bit signal processing is sufficient to obtain a large tolerance towards CD. The proposed modulation and detection techniques enable 111 Gbit/s transmission that is directly compatible with the existing 10 Gbit/s infrastructure.

Coherent Equalization and POLMUX-RZ-DQPSK for Robust 100-GE Transmission

A received signal is first converted into a digital sequence that may contain "erasures" (or ambiguity symbols) as well as errors. Then iterative decoding is applied in order to eliminate or reduce the erasures. This decoding procedure works effectively with the associated transmitter that adopts a concatenation of an outer coder, a permutation and an inner coder. The principal of the invention is also applicable to a system in which the inner coder is replaced by a "digital modulator" that introduces some constraint, or a channel that introduces some memory such as partial response signaling, intersymbol interference or multipath propagation. The invention can be applied to many existing systems while maintaining "backward compatibility" in the sense that the transmitter side need not be modified.

System and method for error correcting a received data stream in a concatenated system

Binary low-density parity-check (LDPC) codes perform very well on magnetic recording channels (MRCs) with additive white Gaussian noise (AWGN). However, an MRC is subject to other impairments, such as media defects and thermal asperities. Binary LDPC codes may not be able to cope with these impairments without the help of a Reed-Solomon code. A better form of coding may be Q-ary LDPC codes, which have been shown to outperform binary LDPC codes and Reed-Solomon codes on the AWGN channel. In this paper, we report on our investigation of Q-ary LDPC coded MRCs, both with AWGN and with burst impairments, and we present a new reduced-complexity decoding algorithm for Q-ary LDPC codes. We show that Q-ary LDPC codes outperform binary LDPC codes in the presence of burst impairments.

/pdf/reduced-complexity-decoding-of-q-ary-ldpc-codes-for-magnetic-312m9r46gb.pdf

Reduced-complexity decoding of Q-ary LDPC codes for magnetic recording

Power line interference may severely corrupt a biomedical recording. Notch filters and adaptive cancellers have been suggested to suppress this interference. We propose an improved adaptive canceller for the reduction of the fundamental power line interference component and harmonics in electrocardiogram (ECG) recordings. The method tracks the amplitude, phase, and frequency of all the interference components for power line frequency deviations up to about 4 Hz. A comparison is made between the performance of our method, former adaptive cancellers, and a narrow and a wide notch filter in suppressing the fundamental power line interference component. For this purpose a real ECG signal is corrupted by an artificial power line interference signal. The cleaned signal after applying all methods is compared with the original ECG signal. Our improved adaptive canceller shows a signal-to-power-line-interference ratio for the fundamental component up to 30 dB higher than that produced by the other methods. Moreover, our method is also effective for the suppression of the harmonics of the power line interference

An Improved Adaptive Power Line Interference Canceller for Electrocardiography

From the Publisher:
Digital Baseband Transmission and Recording provides an integral, in-depth and up-to-date overview of the signal processing techniques that are at the heart of digital baseband transmission and recording systems. The coverage ranges from fundamentals to applications in such areas as digital subscriber loops and magnetic and optical storage. Much of the material presented here has never before appeared in book form.
The main features of Digital Baseband Transmission and Recording include: 
-- a survey of digital subscriber lines and digital magnetic and optical storage; 
-- a review of fundamental transmission and reception limits; 
-- an encyclopedic introduction to baseband modulation codes; 
-- development of a rich palette of equalization techniques; 
-- a coherent treatment of Viterbi detection and many near-optimum detection schemes; 
-- an overview of adaptive reception techniques that encompasses adaptive gain and slope control, adaptive detection, and novel forms of zero-forcing adaptation; 
-- an in-depth review of timing recovery and PLLs, with an extensive catalog of timing-recovery schemes.
Featuring around 450 figures, 200 examples, 350 problems and exercises, and 750 references, Digital Baseband Transmission and Recording is an essential reference source to engineers and researchers active in telecommunications and digital recording. It will also be useful for advanced courses in digital communications.

https://www.springer.com/productFlyer_978-0-7923-9775-5.pdf?SGWID=0-0-1297-33343977-0

J. W. M. Bergmans

Papers

Digital baseband transmission and recording