Title :
Effects of shadowing on non-directed LOS indoor infrared wireless systems with site diversity
Author :
Sato, Akihiro ; Ohtsuki, Tomoaki ; Sasase, Iwao
Author_Institution :
Dept. of Inf. & Comput. Sci., Keio Univ., Yokohama, Japan
Abstract :
We propose the multi-base station (BS) system with site diversity to overcome the effects of shadowing. In the proposed system each BS transmits the same data at the same time. Thus, the symbol rate of the proposed system is almost the same as the bit rate when on-off keying (OOK) is employed, while that of the conventional repetitive transmission system is the number of BSs times as high as the bit rate. The receiver comprises an array of narrow field-of-view (FOV) detectors, like an angle diversity, and can collect signals from some BSs. Thus, the proposed system is robust against shadowing. We consider down link transmission based on time-division multiple access (TDMA) and evaluate the effects of shadowing caused by pedestrians via a theoretical analysis and computer simulation. We show that the proposed system can achieve a higher signal-to-noise ratio (SNR) than the conventional system, and thus can decrease an outage probability, and that the receiver cannot achieve the required bit error rate (BER). We also show that the proposed system is robust against shadowing and can accommodate more calls
Keywords :
amplitude shift keying; digital simulation; diversity reception; intensity modulation; multiuser channels; optical communication; optical links; optical receivers; optical signal detection; time division multiple access; BER; IR wireless systems; OOK; SNR; TDMA; angle diversity; bit error rate; computer simulation; direct detection; down link transmission; intensity modulation; multi-base station system; narrow field-of-view detectors; nondirected LOS indoor infrared wireless systems; on-off keying; outage probability; pedestrians; receiver; repetitive transmission system; shadowing; signal-to-noise ratio; site diversity; symbol rate; time-division multiple access; Bit error rate; Bit rate; Cause effect analysis; Computer simulation; Detectors; Robustness; Sensor arrays; Shadow mapping; Signal to noise ratio; Time division multiple access;
Conference_Titel :
Vehicular Technology Conference Proceedings, 2000. VTC 2000-Spring Tokyo. 2000 IEEE 51st
Conference_Location :
Tokyo
Print_ISBN :
0-7803-5718-3
DOI :
10.1109/VETECS.2000.851387