The new 5G RAN and end-user services needs drive the necessity for a new X-haul transport network and replacement or upgrade of existing transport network. Whereas several 4G assets will be reused, it’ll not be spare to overlay 5G on a 4G backhaul design, even wherever an operator has deployed a sophisticated C-RAN architecture, new investment is needed to fulfil 5G needs.
5G RAN introduces new physical topologies, a lot of practical split choices, and ultra-low- latency services, that demand shorter distances between user and compute. Therefore, there’s a necessity for brand new, flexible, multipoint packet networks within the RAN that may scale and flex to the various deployment models expected for 5G.
Open X-Haul Transport Network Requirements:
As we have already seen in earlier post that RAN architecture deployment shall vary based on service requirements. So, there is a need of X-Haul transport network which shall support all kind of ( fronthaul, midhaul and backhaul ) RAN deployment architecture. Additionally this X-Haul transport network shall provide seamless connectivity for enterprise customer as well.
Requirements for Open X-Haul 5G RAN transport:
- Standards-based – the entire vendor shall follow standard protocol NETCONF/YANG between node and SDN controller. One vendor RU shall interoperate with another vendor DU.
- Packet-based system – To meet the requirement of full mesh connectivity between the RAN, IP based system shall be deployed. We can achieve more flexibility and programmability using IP based system.
- Sync – There is very critical sync requirement in 5G deployment. This sync requirement is more critical when we are moving towards C-RAN deployment architecture.
- Latency – Latency is one of the critical requirements in 5G network. For eMBB service it is approximately 10ms, for URLLC service it is become 1ms. For fronthaul architecture, it is nearly 50 to 100 μs is required (per IEEE 1914.3).
- Multiple fronthaul protocols – Multiple fronthaul protocol support shall be required in 5G. In 4G we have only CPRI interface but in 5G eCPRI, TSN (Time Sensitive Networking), xRAN fronthaul, TIP(Telecom Infra Project) fronthaul, and the proposed “FX fronthaul” interface, may need to be supported.
- Bandwidth & 100-Gbit/s access – Most of the current 4G deployment is having 1G interface connected to cell site. Now 5G demands more bandwidth probably 10G or 25G interface for gNodeB and 100G in uplink shall be required.
- Meshed L3 connectivity – Mesh L3 connectivity shall be required for flexible RAN deployment in various location like pre-aggregation , aggregation and even in edge data center. In this deployment we shall have flexibility to move any function in future in any of the location.