Control and data signaling decoupled architecture for railway wireless networks

Current implementations of narrowband Global System for Mobile Communications for railway systems are facing significant challenges in meeting the emerging massive capacity demands of passenger services. To extend the capacity, this article presents a control and data signaling decoupled architecture, namely, C/U-plane decoupled architecture for railway wireless networks, in which the relatively important C-plane of passenger services is kept on high-quality lower frequency bands to handle mobility, while the corresponding U-plane is moved to higher frequency bands to gain broader spectra. In this railway wireless network with C/U-plane decoupled architecture, the U-plane and C-plane handovers are also physically decoupled. To achieve the seamless and soft U-plane handover, we introduce a handover scheme based on coordinated multi-point transmission and reception and bi-casting. In addition, channel mappings and physical layer frames are redesigned to facilitate the design. Our study has demonstrated that by decoupling the C/U planes, the network performance is greatly enhanced, leading to a more effective way to provide high speed communications for railway systems.