In-Building Wireless in the 5G Era

Nick Marshall: Research Director
As we enter the 5G era, the radio access network (RAN) will undergo structural disruptions as it
evolves to a very high throughput ultra-dense heterogeneous network (HetNet). In this evolving RAN,
exploding data traffic must be managed while maintaining high quality of experience (QoE) and quality
of service (QoS) for the user. In order to accomplish this without also significantly increasing total cost
of ownership (TCO), network architects are adopting techniques such as network functions
virtualization (NFV), software-defined networking (SDN), multi-access edge computing (MEC)
(formerly known as mobile edge computing), and also changing system partitioning and modernizing
fronthaul protocols to transport the very high throughput traffic levels expected in 5G systems.
Although 5G is not yet fully specified, what is clear is that it will be designed for several use cases:
Enhanced mobile broadband (eMBB) promises data rates exceeding 20 Gbps in the access layer, a figure
that is 10X that of today’s fastest 4G systems.
Ultra-reliable low latency communications (URLLC), as its name suggests, reduces latency in the network to
levels that are compatible with real-time applications. URLLC will also feature high levels of uptime so that
5G can be used in life-critical and first responder applications.
Massive machine-type communications (mMTC) is a third use case that envisions large numbers of Internet
of Things (IoT) connections used for applications that connect very large numbers of devices, such as
sensors and actuators used to monitor and control many platforms in segments including industrial,
agriculture, smart city, and many more.
Fixed wireless access (FWA) is the final and probably the first use case to appear on the market, and it can
be thought of as 5G without “mobility” in so far as it is used to transmit RF signals to an antenna on the
customers’ premises using centimeter wave or millimeter wave frequencies, and will be used for broadband
delivery as an alternative to fiber or cable.
Applications based on each of these use cases will appear in buildings and venues, and the
implications are examined in this report. While 5G specifications are still being defined, ABI Research
identifies several challenges in RAN architecture and topology, transport, spectrum and signal
propagation, and antenna configuration that will need further work and research. The main findings
are outlined below.
It is against this background that ABI Research examines in-building wireless RF distribution for coverage
and capacity. Buildings and public venues such as sports stadiums were among the first deployments to
tackle the evolution of the RAN from a distributed topology (D-RAN) to a centralized topology (C-RAN)
distributedantennasystem (DAS),andABI Research expects that it is thenatural next step for these
systems to evolve to virtualized RAN (vRAN) topology as venues prepare for the advent of 5G.