4 February 2013 Space and time diversity in indoor wireless optical links achieving higher data rate
Yazan A. Alqudah
Author Affiliations +
Abstract
Multispot diffusing configuration (MSDC) in optical wireless links provide uniform optical power needed for multiaccess and spatial dependence that can be used to allow space diversity techniques over the link. The spatial channels are furnished in MSDC through utilizing multibeam transmitter that produces spatially confined diffusing spots, and a multibranch receiver with small enough branch field-of-view (FOV) to restrict the number of diffusing spots within its FOV. Here, we study different encoding techniques that use space and time diversity to reduce the bit error rate. An improved technique, constellation rotation, is proposed for pulse amplitude modulated (PAM) to increase the Euclidian distance between signal points, and thus reduce bit error. Our study shows that when a cap is placed on the amount of power allocated per channel, the performance of the improved 4-PAM using three spatial channels and soft binary decision provide the optimal performance. When the power allocated per user is restricted, the best performance is obtained through soft binary decision and by using symbols identified by their level and spatial channel to carry 2 bits per signal level-channel.
© 2013 Society of Photo-Optical Instrumentation Engineers (SPIE) 0091-3286/2013/$25.00 © 2013 SPIE
Yazan A. Alqudah "Space and time diversity in indoor wireless optical links achieving higher data rate," Optical Engineering 52(2), 025004 (4 February 2013). https://doi.org/10.1117/1.OE.52.2.025004
Published: 4 February 2013
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KEYWORDS
Receivers

Signal to noise ratio

Binary data

Transmitters

Channel projecting optics

Reflection

Optical engineering

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