Converged TSN/5G Networks
A current trend in the industry and academia is the endeavour for an unification of communication technologies in order to develop a single technology that is capable to serve diverse real-time and non-real-time applications. A solution discussed by industry and standardization groups to address the novel requirements is Time-Sensitive Networking (TSN). TSN is a set of IEEE 802.1 standards which adopts Ethernet to enable real-time capabilities. In line with the targets of Industry 4.0, wireless technologies will also become an indispensable aspect of future industrial communication at a large scale. The fifth generation cellular network technology (5G) is a promising technology to approach the lack of mobility and scalability in wired networks. 3GPP groups pursue the interest to enable 5G real-time features to make it suitable for industrial applications. Therein, a key aspect is the seamless integration with TSN to establish converged TSN/5G networks.
A prerequisite for industrial applications and real-time communication is a tight synchronization in the time domain. The synchronization in TSN networks is established through the generalized precision time protocol (gPTP) according to IEEE802.1AS. A major challenge of converged TSN/5G networks, with respect to traditional TSN networks, is to achieve and maintain tight synchronization between end-devices. This is because the convergence of TSN and 5G yields the engagement of heterogeneous synchronization mechanisms (gPTP for TSN networks, PTP telecommunication profile for the 5G core, and 5G built-in reference time indication for the radio access network) and because the deployment of radio links introduce uncertainty. A typical requirement for industrial applications is a synchronization accuracy of < 1us.
The integration of TSN and 5G is heavily discussed by both 3GPP and IEEE yielding the integration of 5G with TSN as virtual TSN bridge (VTB) . The VTB enables a seamless integration of 5G with TSN by concealing the 5G complexity using dedicated TSN translators (TTs). These provide a TSN compliant interface towards the TSN network. A key feature naturally is the support of synchronization through the gPTP. From an architectural perspective, the TSN/5G integration as VTB is thoroughly defined. The VTB user plane architecture and the different synchronization mechanisms are shown in the Figure below.
The research objective is to analyse and optimize the synchronization capabilities of converged TSN/5G networks in order to obtain a better understanding of the integration of heterogeneous synchronization mechanisms in such networks and to assess and enable novel industrial applications in line with the trend of Industry 4.0.