Mobile networks are like a congested motorway during rush hour. As soon as a new lane is opened, it is filled with traffic. Similarly in mobile networks, when new applications are introduced, more content is available, new devices are released, and as a result, data usage accelerates.
Indeed, as soon as a network is built, it seems that the conversation immediately moves to upgrading and expanding that network’s coverage and capacity. This article will explore why wireless networks need continuous evolution, how those networks can evolve, and how to manage change in wireless networks.
Drivers of wireless network growth
Networks evolve for two reasons: coverage and capacity. Of these, capacity is the key driver. The explosion of devices – which includes tablets, smart phones and wearables – along with the proliferation of applications, video usage and gaming, are all rapidly driving up bandwidth usage on wireless networks.
Simply put, wireless users expect to be able to do anything with their devices anywhere they go, so a macro network based solely on tower antennas is no longer sufficient to meet the need.
Today’s operators use technologies like distributed antenna systems (DAS) and small cells to add capacity to existing macro networks, and these technologies are also used in stadiums, airports, railway stations, office parks, and other venues where large crowds gather.
How large of a problem is capacity? Consider: The Internet of Things (IoT) will have an estimated 22 billion devices attached by the year 2020, according to Gartner. There is also a rapid expansion of 3G mobile broadband into rural areas, and the International Telecommunication Union (ITU) estimates that 29% of the 3.4 billion people worldwide living in rural areas will be covered by 3G mobile broadband by the end of 2015.
Europeans represent 10.4% of the global population, but are 17.2% of global mobile users, according to a 2014 We Are Social survey, and ITU reports that Europeans have a 139% mobile device penetration rate, meaning that users typically have more than one wireless device.
Key requirements for scalable wireless infrastructure
Operators have used a variety of strategies to scale their networks: for example, adding cell sites, sectorising or splitting cell sites, adding additional channel cards for capacity or extending coverage with solutions such as repeaters, radio heads and DAS.
As mobile networks have evolved and migrated to fibre optics, there are several additional ways to scale a network to add coverage and capacity, and wireless planners should be aware of their options in order to build networks that can easily expand.
Multiplexing – In urban and suburban spaces as well as large venues, digital wireless networks use fibre as a transport medium. By using technologies such as coarse wave division multiplexing (CWDM) and dense wave division multiplexing (DWDM), network engineers can leverage existing fibre to expand the wireless network.
Multiplexing technologies such as these allow engineers to use new wavelengths on existing fibre to carry wireless traffic, thereby saving the expense of adding new fibre.
Multi-frequency support – One of the key ways for mobile operators to add capacity to a network is to increase the number of frequency bands used. A wireless system like a DAS should be able to support multiple frequency bands so the system can be cost-effectively expanded.
Some DAS solutions can carry up to eight frequency bands with a single set of electronics. Such systems also make it easier to support new technologies like multi-input/multi-output (MIMO).
Cascading architecture – When a DAS is expanded to support new areas of a building or urban/suburban area, wireless planners want to avoid having to build an entirely new system to cover the new area. DAS products that use a cascading architecture allow planners to add new antenna systems to an existing wireless topology.
Connectorised networks – Modern fibre networks use push-on connectors that eliminate labour-intensive and expensive splicing. By using a connectorised network, architects can ensure that expanding the network is easier, faster, and more cost-effective.
Use of existing or new deep fibre networks – Some operators have utilised existing fibre infrastructure from their own network or another provider to expand the reach of their mobile networks by overlaying wireless access systems. Fibre to the home or business (FTTH/B) networks provide the access and backhaul for small cells and DAS.
Precision coverage options – When filling in capacity in existing wireless networks, network engineers need high-precision coverage options that do not interfere with the network that is already there. Having a selection of low-power and high-power remote antenna units makes this task easier, by using the right solution for the environment to strategically tailor the service area.
Digital transport – Using wireless systems that leverage digital transport gives planners much more flexibility to expand networks and network capacity. Analogue signals attenuate with distance, making analogue systems suitable only for mid-sized and smaller applications, whereas digital systems can transport wireless signals for dozens of kilometers and with a higher optical budget, have a greater loss tolerance to provide a high level of signal quality even in areas with higher optical loss from splicing, for instance.
Managing network growth
As mentioned earlier in this article, network growth can occur due to capacity or coverage issues. When the issue is coverage, the network can be expanded through the use of additional expansion hubs and remote antenna units. When the issue is capacity, engineers can re-sectorise the network.
Sectorisation is a time-honoured method of expanding wireless network capacity, dating back to macro cells 15 to 20 years ago. With sectorisation, an existing wireless coverage area is subdivided into multiple coverage areas, each with its own dedicated capacity. Today, stadiums, urban areas, and suburban neighbourhoods are often re-sectorised to expand capacity.
Ultimately, by selecting wireless network systems that meet a few key requirements, network engineers can deploy infrastructure that will grow and evolve as the market drives applications and data usage forward.