7 - Throughput of cellular OWC networks
Published online by Cambridge University Press: 05 March 2015
Summary
Introduction
An optical wireless communication (OWC) multiple access network can deliver wireless data to multiple mobile users. In order to maximize the coverage area, a cellular network approach can be deployed. The time and frequency resources can be allocated to the cells in a static fashion using resource partitioning with wavelength/frequency reuse or by means of a dynamic interference-aware scheduling. An aircraft cabin has been considered as a representative indoor scenario since: (a) it provides a very dense distribution of users, and hence results in an interference-limited environment; (b) it is a scenario where radio frequency (RF) communication is not preferred; and (c) it allows very small cells. It is well known that the introduction of small cells is one of the key reasons for the significant network spectral efficiency increase in RF cellular communications.
In this chapter, first, a cellular OWC system based on orthogonal frequency division multiplexing (OFDM), i.e. optical OFDM (O-OFDM), with static resource partitioning is considered inside an aircraft cabin. Asymmetrically clipped optical OFDM (ACO-OFDM) and direct-current-biased optical OFDM (DCO-OFDM) transmission schemes are compared in terms of throughput and cell coverage. Wavelength reuse factors of 1 (full reuse), 2, and 3 are studied, and off-the-shelf optical front-end components are assumed. The signal and interference distributions in an indoor cellular network can be accurately modeled by means of a Monte Carlo ray-tracing (MCRT) global irradiation simulation in a computer-aided design (CAD) cabin model. Due to the use of OFDM, adaptive modulation and coding (AMC) can be applied to the signal-to-interference-and-noise ratio (SINR) maps to obtain the spatial throughput distribution inside the cabin [16, 17]. It is shown that throughput within the range of 1.56–30 Mbps is achievable with the considered ACO-OFDM system, while DCO-OFDM doubles the throughput to 3.13–60 Mbps. In addition, wavelength reuse factors of 3 or higher are needed to ensure full cell support for both transmission schemes.
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- Principles of LED Light CommunicationsTowards Networked Li-Fi, pp. 151 - 182Publisher: Cambridge University PressPrint publication year: 2015