21581 - SCTE Broadband August2022 COMPLETE v1

60 Vol. 44 No. 3 - September 2022 Issue technical 5G interfaces To improve the throughput of the fronthaul connection, 5G introduces eCPRI—a new protocol to connect the DU to the RU. eCPRI uses Ethernet as its physical layer and runs over an FTTA connection. This provides faster link rates of 10Gbit/s and 25Gbit/s, and more efficient use of fronthaul bandwidth. Communication between the CU and the DU is covered by another Ethernet-based protocol stack called the F1 interface. Since RU, DU and even CU functions can be grouped together in a single device, cell sites may be connected to the rest of the infrastructure through either of these interfaces, depending on the operators chosen network architecture. Another architectural improvement is called mobile edge computing (MEC). MEC allows the operator to move computation resources closer to the edge of the network. Doing so provides two benefits. First, latency is reduced providing faster response times for application. Second, as this reduces packets travelling through the core, network congestion in the core is reduced. Figure 3: An example of a 4G fronthaul architecture Figure 4: An example of a 5G fronthaul architecture Figure 5: Xhaul network components