By: Per Lindberg

It’s 2020 and the race for 5G is accelerating—and changing course. First, it’s moving indoors, and it’s important to understand why it matters and how it will happen. In addition, the drive for more automation and openness with the increasing influence of the O-RAN Alliance is further shaping the shift. And looking forward amid today’s mounting environmental crises, dynamic self-optimising networks will help the industry make a valuable contribution to saving the planet. 

Traditionally, operators have owned the outdoor space and relied on macro cells to penetrate indoors. This is at best a compromise, leaving many without coverage and reliant on Wi-Fi, if available. The fact is that, while some 80 percent of all data is consumed from indoors, only about two percent of buildings in urbanized environments have dedicated indoor cellular networks. The problem is only going to get worse as the 5G rollout accelerates. This is because higher frequencies find it harder to penetrate most building materials such as bricks and concrete, steel frames, glass, insulation and wood, leading to increased penetration loss and weak indoor coverage, or none at all.

Operators are waking up to these challenges. In 2020 and beyond, they will focus much more on the in-building environment to provide ubiquitous connectivity and a seamless user experience both indoors and out.  In addition to Tier 1 sites such as large hotels, shopping malls, stadiums and campuses, attention will be turning to offices, residential buildings, smaller hotels and hospitals, for example. This rush indoors will continue to gain pace, and by 2030 we expect to see the percentage of buildings with their own indoor networks to grow to around 10 percent, with 5G connectivity present in millions of buildings worldwide.

The 5G indoors challenge

There are two options to deal with the indoor challenge: by deploying small cells or DAS (Distributed Antenna Systems), which can deliver greater speed, throughput and agility. The large capacity of DAS is well-suited to venues such as stadiums. It is also much less expensive to deploy a DAS for in-building coverage than to install hundreds of small cells. DAS tends to involve higher upfront costs with heavier design work than small cells in low-density applications. The challenge is determining where the tipping point is. Over the next 12 months, we expect to see the ramping up of small cell deployments, whether as an integral part of DAS or as separate units.  

Whether using a small cell or DAS system, however, there is a need for a new generation of indoor-outdoor network design and optimization tools. These new tools must be capable of planning and deploying densified indoor and urban networks, allowing users to easily and accurately plan and simulate the performance of complex coordinated multilayer and multi-technology networks both indoors and out.

Another design challenge is the need to prevent interference between indoor ‘private’ networks and outdoor public networks. For example, if a hotel wants a cellular indoor network, there is a need—and possibly a legal requirement—to consider leakages between indoors and outdoors.

Another driver for better indoor cellular coverage is the industrialization of mobile networking and the creation of smart factories and enterprises. This industrialization of 5G is being pioneered in China based on the new core network, called ‘5G standalone.’ Consider the industrial 5G use cases such as machine control, robots and unmanned vehicles, or the need to link IoT networks and AR/VR vision systems inside the factories of the future. These use cases will require ultra-low latency and much higher capacities. This is only feasible with higher-frequency SA 5G NR and the 3GPP core network architecture for 5G Core (5GC). Companies will be able to link up different factory sites and locations using seamless 5G networks and not rely on using disparate Wi-Fi networks in buildings.