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13 December 1999 Design and evaluation of a 2-Mb/s GMSK modem for short-distance infrared wireless communications
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Proceedings Volume 3850, Optical Wireless Communications II; (1999)
Event: Photonics East '99, 1999, Boston, MA, United States
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).
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Rafael Perez-Jimenez, Cesar Montelongo, and Jose A. Rabadan Borges "Design and evaluation of a 2-Mb/s GMSK modem for short-distance infrared wireless communications", Proc. SPIE 3850, Optical Wireless Communications II, (13 December 1999);

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