Reliability evaluation of 5G C/U-plane decoupled architecture for high-speed railway

Abstract

To facilitate the mobility of heterogeneous networks, control plane (C-plane) and user plane (U-plane) decoupled architecture is being considered by the fifth generation (5G) wireless communication network, in which relatively crucial C-plane is expanded and kept at dependable lower frequency bands to guarantee transmission reliability and the corresponding U-plane is moved to available higher frequency bands to boost capacity. Moreover, we apply this architecture to future professional high-speed railway wireless communication system to fulfill the wireless access desire of train passengers. However, for such emerging architecture, there still exist many problems to be solved to guarantee the reliable transmission. In this article, the problem of how to appropriately evaluate the transmission reliability of C/U-plane decoupled architecture is investigated. Due to the lack of ability to reflect the importance of C-plane, conventional outage probability cannot properly indicate the transmission reliability of C/U-plane decoupled architecture whose primary design consideration is that C-plane more heavily affects the transmission reliability thereby being kept at dependable lower frequency bands. Based on this, a novel indicator named unreliability factor (URF) is proposed. Theoretical analysis and simulation results demonstrate that URF can exactly highlight the effects of C-plane on the entire transmission process. Hence, it is more appropriate to employ URF as the indicator to evaluate the transmission reliability of C/U-plane decoupled architecture.

Softwarization and virtualization in 5G mobile networks: Benefits, trends and challenges

“…Another decoupling aspect is having a decoupled C/U-plane association to increase for instance the reliability of C-and U-plane traffic or to reduce the amount of control traffic (for instance, in an Intelligent Mobility (IM)/ITS scenario, involving having a C-plane connection to a macro BS to minimize the number of handover while having a U-plane connection with small cells to increase the capacity) [96].…”

A Low-Latency Collaborative HARQ Scheme for Control/User-Plane Decoupled Railway Wireless Networks

“…In order to increase the system capacity to meet the wireless access demands of train passengers, a C/U-plane decoupled railway wireless network was proposed in [4], [5]. As shown in Fig.…”

“…To this end, industrial participants have reached the consensus that the current narrowband GSM-R (Global System for Mobile Communication for Railway) will evolve to long term evolution (LTE) for railway communication systems in the near future [2], [3]. In addition, a C/U-plane decoupled railway wireless network was proposed [4], [5]. To address the problems caused by the direct connection between onboard passengers and wayside base stations, an access point (AP) is deployed inside the train to collect passengers' services in this network.…”

“…8, respectively. Detailed simulation parameter settings are listed in TABLE II [4], [5]. For clarity, here two small cells symmetrically located in the coverage of a macro cell are taken into account.…”

METIS research advances towards the 5G mobile and wireless system definition

“…Given this, it is possible to transmit the Cplane, and consequently HO messages, from a stable macro cells whereas the U-plane is transmitted from the closest small cell (see Figure 2). The recent work by Li Yan et al argues about the suitability of this approach for future 5G networks and provides interesting insights on practical aspects [19]. Another important problem is the provision of highquality services within vehicles on the move.…”