We address the problem,‘Is a local tree structure sufficient for the local optimality of message passing algorithm in low density parity check codes?’.It is shown that the answer is negative. Using this observation, we pinpoint a flaw in the proof of Theorem 1 in the paper ‘The Capacity of Low-Density ParityCheck Codes Under Message-Passing Decoding’ by Thomas J. Richardson and Rüdiger L. Urban...

In this paper, Bit Error rate and probability of outage are derived in closed form for plane wave mode over Gamma-Gamma free space optical channel under the influence of pointing errors and different weather conditions. The free-space optical system under study assumes deployment of intensity modulation / direct detection with on-off keying data formats. To evaluate the performance of the syste...

Future wireless video transmission systems will consider orthogonal frequency division multiplexing (OFDM) as the basic modulation technique due to its robustness and low complexity implementation in the presence of frequency-selective channels. Recently, adaptive bit loading techniques have been applied to OFDM showing good performance gains in cable transmission systems. In this paper a multi...

This paper presents a new parallel transmission framework for reliable multimedia data transmission over spectrally shaped channels using multicarrier modulation. We propose to transmit source data layers of different perceptual importance in parallel, each occupying a number of subchannels. New loading algorithms are developed to efficiently allocate the available resources, e.g. transmitted p...

The prohibitive—exponential in the number of users—computational complexity of the maximum-likelihood multiuser detector for direct-sequence code-division multiple-access communications has fueled an extensive research effort for the development of low-complexity multiuser detection alternatives. In this letter, we show that we can efficiently and effectively approach the error rate performance...

n-3 Polyunsaturated fatty acids (n-3 PUFA)-enriched phosphatidylcholine (PC) was successfully produced with fatty acid from fish oil and PC from soybean by immobilized phospholipase A1-catalyzed acidolysis. Detailed studies of immobilization were carried out, and Lewatit VP OC 1600 was selected as a carrier for preparation of immobilized phospholipase A1, which was used for modification of PC b...