[IEEE Link]
LiFi (Light-fidelity) is known as a networked visible light communication (VLC) system, which is able to deliver high speed broadband services to a large number of mobile users with multiple access and mobility support. In order to achieve this VLC-based network, a reliable high speed uplink connection is essential and wireless infrared (IR) communication is found to be a promising solution. However, it is challenging to use unidirectional wireless IR transmitters and receivers to achieve reliable uplink connections. In order to enhance the uplink channel quality in LiFi systems, we propose a transmitter and receiver design with omnidirectional characteristics. The proposed designs have been validated by experiments. In addition, simulation studies show that by using the proposed transmitter/receiver, the quality and the robustness of the LiFi uplink channel can be improved.