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Proceedings Paper

Intensity distribution based space and time division multiple access technique for hybrid-LOS indoor optical wireless communication
Author(s): Shinichi Miyamoto; Kenji Kawamoto; Seiichi Sampei
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Paper Abstract

This paper proposes a space division and time division multiple access (SD/TDMA) technique based on intensity distributions for hybrid line-of-sight (hybrid-LOS) indoor optical wireless communication system. At first, a novel signal discrimination scheme for the spatially multiplexed optical signals is proposed and it is applied to a space division multiple access (SDMA) in hybrid-LOS system. In the proposed scheme, multiple terminals simultaneously transmit their optical signals to access point (AP) using on-off-keying (OOK) modulation, and the spatially multiplexed optical signals are received by a photodetectors array (PD-array), where multiple PDs are disposed to observe the spatial intensity distribution of optical signals. Because the terminals transmit their data using OOK modulation, the spatial intensity distribution observed by the AP equipped with PD-array is subject to the data transmitted from individual terminals, and the AP can identify the terminals transmitting the optical signal by determining the transmitted intensity distribution. Of course, the transmitted intensity distributions are not orthogonal signal and the discriminability of transmitted intensity distributions is much related to the differences of intensity distributions. This implies that the number of terminals that can simultaneously access to the AP will be limited and it is determined by the differences of the candidate intensity distributions. In order to enhance the discriminability of the transmitted intensity distributions, the proposed signal discrimination scheme is further applied to the SD/TDMA. In the SD/TDMA, the discriminability required to enable SDMA is ensured by introducing a scheduling algorithm in which terminals with higher discriminatory of transmitted intensity distributions are allocated to the same time slot. Numerical results show that SD/TDMA using proposed signal discrimination scheme increases the throughput and the number of terminals that can access to the AP.

Paper Details

Date Published: 26 February 2010
PDF: 12 pages
Proc. SPIE 7587, Free-Space Laser Communication Technologies XXII, 75870W (26 February 2010); doi: 10.1117/12.840807
Show Author Affiliations
Shinichi Miyamoto, Osaka Univ. (Japan)
Kenji Kawamoto, Osaka Univ. (Japan)
Seiichi Sampei, Osaka Univ. (Japan)

Published in SPIE Proceedings Vol. 7587:
Free-Space Laser Communication Technologies XXII
Hamid Hemmati, Editor(s)

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