The importance of xHaul for the success of 5G

Mobile operators in all Asian markets are facing the same design and implementation challenges:

1. 5G Massive MIMO antenna placement for coverage and capacity
2. Network density, considering existing cellular grids for 3G and 4G
3. Transport-network planning, especially for converged fixed/mobile operators

Transport network considerations are important in 5G as they are becoming more complex. Previously, backhaul was the only necessary consideration and mobile operators had to design these networks using end-user traffic dimensioning. However, 4G and 5G require backhaul, fronthaul, and midhaul that include Carrier Ethernet, CPRI, eCPRI, new types of fronthaul, and the requirement to support new functional splits as specified by a variety of industry bodies including 3GPP, the ORAN Alliance, and the Small Cell Forum.

Previous cellular-network deployments have proven that transport infrastructure is vital for a successful commercial launch. For example, Verizon was the first to commercialize 4G by having a dense optical network for 4G backhaul. In Japan, Rakuten deployed an Open RAN network by making extensive use of its optical backbone.

Now more than ever, transport-network planning needs to take place proactively, especially when new types of services – including IoT, deterministic networking, and low latency communications – enter the market.

5G transport network planning considerations

Transport-network planning is vital in both consumer and enterprise domains, especially as telecom operators are now under competitive pressure inside and outside the established value chain. In the value chain, operators are operating in saturated markets with shrinking profit margins in the consumer space. In the enterprise domain, they are competing against hyperscalers that are innovating at a rapid pace. It’s no wonder telecom operators are planning their future strategies and eagerly trying to remain competitive and profitable. The transport network is a big part of their future.

In the consumer domain, transport network planning is currently a vital, and more complex part of the telecom operator future. Open RAN and 5G have complicated transport network planning with functional splits, distributed network components, and several fronthaul options. The dynamic nature of future network configurations requires the transport network to be significantly robust and flexible to cater for any potential shift in direction.

For example, a Western-European Tier-1 converged operator has reported that Open RAN trials with the 7.2x fronthaul configuration translated to an increase in transport-network traffic, which could cannibalize the transport-network capacity allocated to fixed-broadband capacity if not managed correctly. The transport network has become a make-or-break factor for public macro-cellular networks, accentuated in 5G where Massive MIMO has introduced a major capacity boost.

In the enterprise domain, telecom operators are planning network slicing, distributed service chaining, and edge computing services. All of these require a cutting-edge last-mile network deployment, strong telco cloud capabilities and consistent orchestration across these domains. The interface that binds all these together is the optical-transport network, which can define the type of services that will be offered. For example, the latency range that can be offered through Ultra-Reliable Low-Latency Communications (URLLC) in 5G may be defined by the transport network performance and distance to the telecom edge server.

Automating the future of 5G

The future of 5G presents an exciting opportunity for telecom operators: immersive user experiences in the consumer domain and advanced digital services for enterprises. Both translate to service granularity – where each user group and enterprise vertical are managed independently – to enable differentiated services and unique user experiences.

However, managing and orchestrating the network that provides these granular services cannot be done manually due to the multitude of processes that are required. Thus, network automation is necessary for the future of both consumer and enterprise domains. Network functions must be designed, deployed, managed, and decommissioned in an automated manner with minimum human intervention.

For example, a machine-vision application enabled by 5G in a smart city will be able to detect a surge in pedestrian traffic and direct the network to allocate more cellular capacity to this area while ensuring that the transport network is also adequately provisioned to handle this traffic. In the enterprise domain, a mission-critical application will be able to detect an unplanned event and allocate a low-latency channel in the radio and transport domains to ensure that an adequate response is executed.

xHaul networks are the foundation for successful deployments in the consumer domain and will become a key enabler in the enterprise domain as well. ABI Research estimates that optical transport network investments will continue to rise in importance and will become the enabler of the next wave of telecom network profitability.