Nonbinary LDPC-Coded Modulation for High-Speed Optical Fiber Communication Without Bandwidth Expansion


We propose a scheme that can attain the same transmission bit rate as the corresponding conventional polarization-division-multiplexed (PDM) quadrature amplitude modulation (QAM) scheme while occupying lower bandwidth and, hence, achieving a higher spectral efficiency. In contrast to the conventional approach, which increases the symbol rate and thus the occupied bandwidth to transmit the redundant symbols due to forward error correction (FEC), the proposed approach expands the underlying signal constellation in size and reduces the FEC code rate accordingly to form a mechanism that can achieve coded transmission without bandwidth expansion. Such a scheme can find applications in scenarios where there exist stringent bandwidth restrictions and bandwidth expansion is not considered as a viable option. Although the idea of constellation expansion in lieu of bandwidth expansion is mainly associated with Ungerboeck's trellis-coded modulation (TCM), our proposed nonbinary low-density parity-check (LDPC)-coded modulation scheme shows that block-coded modulation schemes can also be used with expanded constellations to achieve transmission without bandwidth expansion and without resorting to TCM. Our results reveal that for small to medium constellation sizes, the proposed scheme can preserve bandwidth while not experiencing significant increase in required optical signal-to-noise ratio (OSNR). For large constellation sizes, however, to keep the increase in required OSNR at manageable levels, we propose using controlled bandwidth expansion where constellation expansion and bandwidth expansion are used simultaneously to obtain a balance between the two critical system parameters of bandwidth and required OSNR.

Did you like this research project?

To get this research project Guidelines, Training and Code... Click Here

PROJECT TITLE :Two-Extra-Column Trellis Min–Max Decoder Architecture for Nonbinary LDPC Codes - 2017ABSTRACT:In this temporary, a unique two-extra-column trellis min-max algorithm and therefore the decoder architecture based
PROJECT TITLE :High-Speed Parallel Decodable Nonbinary Single-Error Correcting (SEC) CodesABSTRACT:This paper presents a unique construction scheme for nonbinary single-error correcting (SEC) codes that yields highspeed parallel
PROJECT TITLE :Reduction of Complexity for Nonbinary LDPC Decoders With Compressed MessagesABSTRACT:In this transient, a methodology for compressing the messages between check nodes and variable nodes is proposed. This technique
PROJECT TITLE :Loop Calculus For Nonbinary Alphabets Using Concepts From Information GeometryABSTRACT:The Bethe approximation could be a well-known approximation of the partition operate utilized in statistical physics. Recently,
PROJECT TITLE :Constructions of Nonbinary WOM Codes for Multilevel Flash MemoriesABSTRACT:The goal of this paper is to present constructions of high-rate nonbinary write-once memory (WOM) codes for multilevel flash memories. The

Ready to Complete Your Academic MTech Project Work In Affordable Price ?

Project Enquiry