Benoit Geller

Equalizer for video rate transmission in multipath underwater communications

This paper concerns the equalization problem of an underwater high rate transmission system. Because the channel delay spread of an horizontal link is large compared with the data duration, we have developed an adaptive equalizer in order to minimize the calculus burden of the moving receiver. The performance of this equalizer on synthetic and real channels is discussed.

Block Turbo Codes: From Architecture to Application

This paper is concerned with the design of block turbo codes for very high bit rate applications. We first introduce an original low-complexity architecture designed for the iterative decoding of product codes. The implementation of the Chase-Pyndiah algorithm is simplified by not memorizing any of the list decoding concurrent code words. We then illustrate that such block turbo codes allow some bit rate improvement in the context of local loop transmission

An algorithm for blind equalization and synchronization

Abstract This article concerns the problem of blind equalization. In practical situations, one must synchronize the receiver with the transmitter. The classical use of two separate algorithms, one for synchronization and one for equalization, does not work correctly as the channel interference increases. In such cases, one must prefer a joint estimation of the two unknown parameters (synchronization and equalization). Here, an original algorithm that jointly estimates the synchronism and the equalizer without any training period (blind estimation) is proposed. This algorithm is validated using both synthetic and real data. This study is limited to constant modulation schemes such as PSK.

A new iterative phase tracking scheme

This paper presents a new synchronizing scheme designed for block turbo coded systems. The phase estimation relies on the feedback of the extrinsic information. A near optimum version of the algorithm based on the block turbo decoder devised by Pyndiah (1998) allows easy implementation. We display various results showing that the proposed algorithm is able to track frequency shifts and that it works very well in the case of general quadrature amplitude modulation (QAM) constellations. We also show that this turbo synchronizer works at low signal to noise ratios (SNR) taking completely advantage of the turbo coding possibilities.