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Design and implementation of 1GbpsLaser Ethernet Transceiver (LET) for Free-Space Optical communications
KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
2014 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Free Space Optical (FSO) communications are an emerging technology. Multiple

resources around the world are being dedicated to the study and implementation of

associated technologies. The possibility of high data rates, lower masses and more

power efficient antennas are the expected advantages of these systems.

However FSO channels are highly vulnerable. Atmospheric perturbations as well as

pointing misalignments compromise the integrity of the transmitted data. Besides,

current data protection architectures for FSO communication systems are not

powerful enough to protect the data due to the nature of the perturbations.

Therefore, Deutsches Zentrum für Luft- und Raumfahrt (DLR) is working on the

implementation of a communication protocol (Laser Ethernet Transceiver protocol,

LET) capable of transmitting high bit rates reliably.

LET has to overcome the multiple errors induced by the disturbances in the channel

(fades in the signal induced by the atmosphere and miss-pointing) and data stream

misalignments during transmission. In addition, LET has to provide a framework for

transmitting 1GbE (Gigabit Ethernet) payloads. Thus the focus of this MSc Thesis is

on the definition and implementation of the abovementioned algorithms and

hardware structures. These hardware structures are developed for their integration

on Field Programmable Gate Arrays (FPGA) in VHDL language.

At the end of this MSc Thesis, a significant improvement of 3.5 dB in the optical

gain has been achieved with a Bit-Level Forward Error Correction (BLFEC)

implementation. Some of the hardware structures have also been implemented and

tested for the next steps. An analysis of the synchronization problems that will

affect the system has been done and a technical solution has been provided.

Additionally, an improvement of the channel throughput has been achieved in order

to comply with the 1GbE Standard.

Place, publisher, year, edition, pages
2014. , 102 p.
EES Examensarbete / Master Thesis, XR-EE-SPP 2014:004
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
URN: urn:nbn:se:kth:diva-152465OAI: diva2:750057
Educational program
Master of Science in Engineering - Information and Communication Technology; Master of Science - System-on-Chip Design
Available from: 2014-09-26 Created: 2014-09-26 Last updated: 2014-09-26Bibliographically approved

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