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Proceedings Paper

Design and evaluation of a 2-Mb/s GMSK modem for short-distance infrared wireless communications
Author(s): Rafael Perez-Jimenez; Cesar Montelongo; Jose A. Rabadan Borges
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Paper Abstract

A carrier-based modem for an IR Wireless LAN (IR-WLAN) design is presented. It is based on GMSK modulation schemes. This modem is capable of operating at 2 Mb/s, but it can easily modify to work up to 4.8 Mb/s. GMSK Schemes are filtered modulation schemes with higher spectral efficiency and robustness against jitter than basic FSK. The emitter uses a pulse-conformation stage for full-digital gaussian pulse conformation. Transitions are codified and the resulting waveform is similar to the output of a gaussian filter. The main applications of the proposed GMSK modem are in the area of a full-duplex IR link. And can be applied either in point-to-point links or into a local area network. It can work without interference wither with IrDA systems (even with the proposed PPM 4.4 Mb/s link) or with IEEE 802.11-baseband link (1 or 2 Mb/s). It is also more spectral efficient and jitter resistant than PPM. Carrier-based systems can be used either in point-to-point links or in diffuse systems. For diffuse systems, this modem assumes a high level of use of the available IR spectrum, supporting at least 4 channels in a 30 MHz bandwidth. We also compare the performances of GMSK with other schemes (as can be OQPSK or FQPSK-2).

Paper Details

Date Published: 13 December 1999
PDF: 8 pages
Proc. SPIE 3850, Optical Wireless Communications II, (13 December 1999); doi: 10.1117/12.372824
Show Author Affiliations
Rafael Perez-Jimenez, Univ. de Las Palmas de Gran Canaria (Spain)
Cesar Montelongo, Univ. de Las Palmas de Gran Canaria (Spain)
Jose A. Rabadan Borges, Univ. de Las Palmas de Gran Canaria (Spain)

Published in SPIE Proceedings Vol. 3850:
Optical Wireless Communications II
Eric J. Korevaar, Editor(s)

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