5th Generation (5G) is the next step of mobile telecommunication standards. It will offer new services with ultrahigh system capacity, ultralow latency, massive device connectivity, ultrahigh security, ultralow energy consumption, and extremely high quality of experience (QoE). Researchers all over the world are focusing on the development of 5G communication systems, aiming to be fully available for the users by 2020. This era of wireless communication will bring new exclusive network technologies and service capabilities. Small cell network technologies will be the key driver for the 5G communication. It is expected that 5G communication will consist of ultradense heterogeneous small cell networks. The use of the traditional radio frequency- (RF-) based wireless communication is being saturated to meet the demand of 5G. Hence, researchers are searching for new spectrum for wireless communication. The optical spectrum (infrared, visible light, and ultraviolet) is considered a promising solution for the development of future high density and high capacity optical wireless communication (OWC) networks. The OWC offers unique advantages such as huge unregulated bandwidth and inherent security. Therefore, the coexistence of RF based omnidirectional and OWC based directional small cells will be the excellent approach for the targeted multitier ultradense heterogeneous networks in 5G.

This special issue calls for high-quality and unpublished research papers on recent advances mainly in emerging small cell wireless technologies that are expected to meet the requirement of the 5G communication systems. Contributions may present and solve open research problems, integrate novel solutions efficiently, focus on the performance evaluation, and compare with existing standards. Theoretical as well as experimental studies for typical and newly emerging small cell wireless technologies use cases enabled by recent advances in wireless networks are encouraged. High-quality review papers are also welcomed.

Potential topics include but are not limited to the following:

• Optical wireless communication (OWC)
• Visible light communication (VLC)
• Optical camera communication (OCC)
• Light-fidelity (LiFi)
• RF small cell networks
• V2X communications
• Small cell based applications and services
• Coexistence of optical and RF based wireless technologies
• Traffic offloading in multitier heterogeneous networks
• Convergence of small cells with higher-tier networks
• Spectrum allocation and management
• Interference management for ultradense small cell networks
• Quality of service (QoS)/quality of experience (QoE) constraints
• Integration of emerging OWC standards with existing RF standards