Spectral Efficient Cooperative Downlink Transmission Schemes for DCO-OFDM-Based Optical Attocell Networks

Abstract: In this study, novel spectral efficient cooperative transmission schemes are proposed for downlink in indoor light-fidelity (Li-Fi) cellular networks, also termed optical attocell networks. Downlink cooperation builds upon dual-hop decode-and-forward (DF) relaying with the aid of one or two neighbouring base stations (BSs). The connections between the source BS and the relay BSs are provided by perfectly aligned visible light communication (VLC) links. Two cooperation protocols are introduced and evaluated, namely, non-orthogonal DF (NDF) and joint transmission with DF (JDF). A multiple access system based on direct current optical orthogonal frequency division multiplexing (DCO-OFDM) with inter-cell interference (ICI) mitigation using fractional frequency reuse (FFR) is considered. Also, a line-of-sight (LOS) Lambertian propagation model is used for the indoor VLC channel. For each scheme, the signal-to-interference-plus-noise ratio (SINR) and spectral efficiency for user equipment (UE) with random coordinates in an attocell are derived. The average spectral efficiency within an optical attocell is studied using Monte Carlo simulations.

Biography: Hossein Kazemi received his M.Sc. degree on analog integrated circuits from the department of electrical engineering, Sharif University of Technology, Tehran, Iran in 2011, and his M.Sc. degree (1st class honours) on communication systems from the department of electrical and electronics engineering, Ozyegin University, Istanbul, Turkey in 2014. He is currently working toward his Ph.D. degree under the supervision of Professor Harald Haas at the institute for digital communications, University of Edinburgh, Edinburgh, UK. His research interests include wireless communications with emphasis on optical wireless communications.