There are several distinct scenarios for bringing cellular service to rural and remote areas. Locations may be completely isolated or just on the edge of macrocell coverage, using a variety of options for backhaul. We’ve simplified these into three distinct categories discussed below.
Isolation or Integration
It’s often observed that the population distribution isn’t spread evenly throughout a country. Humans have been social animals for millennia and naturally group together into small and large communities. Achieving high population coverage above 90% in a country can therefore be met with as little as 70% or lower geographic coverage. For example, there must be huge swathes of Canadian tundra or Australian outback without any cellular service at all.
Interest to increase geographic coverage seems to be gaining momentum at the moment. Vodafone have committed to population coverage of 98% for LTE across the UK by the end of 2015 (up from about 60% today). This may appear to go further than the joint commitment by all UK mobile operators to achieve 85% geographic coverage by end 2017, but may not necessarily be the case.
Wide area geographic coverage inevitably starts with large and expensive cell towers. Increasing population coverage in these sparsely populated areas can be much more focussed, and achieved with targeted and low cost small cell solutions.
The US Government has validated claims that 98% of the population can receive LTE. Both Verizon and AT&T exceed 300 million, with T-Mobile catching up later this year. You can see from the linked coverage map (Courtesy Opensignal showing LTE from any/all networks) that there’s still a fair few white non-coverage areas on the west half of the country. Coverage outside some rural towns can be limited. Alaskan polar bears wouldn’t get much reception either. Australian coverage is very much oriented around the coastal population centres.
The Three levels of rural coverage
The Small Cell Forum distinguishes between remote (where there is absolutely no cellular service) and rural (which might be on the edge). We’ve further refined that into three classifications, which we’ve titled Oasis, Pocket and Infill.
Imagine a small outpost such as a truck stop on a remote outback highway or a hamlet in the Scottish Highlands with absolutely no cellular service – miles from the nearest cell tower. Just as you would expect to quench your thirst from a well at a desert oasis, digital communications can be reconnected here.
A relatively low power small cell can be used inside or attached to a building to provide service within a few hundred metres. These are best configured as open access and provide seamless service to those on that network. There’s no issue with interference to the rest of the network because there’s no signal. That also means the choice of frequency band to use is wide open and will operate to its full potential.
For larger villages, two or three small cells might be installed. They would automatically configure themselves with power and frequency, and can enjoy the luxury of using different frequency bands.
Vodafone UK adopt this approach with their Rural Open Sure Signal (ROSS) program, which has equipped 100 remote communities with 3G service. Rather than imposing the solution onto an unwilling public, each local village has to support their installation, apply to join the program and nominate a Village Champion. Community buildings, such as the local village hall or post office, are a popular choice of site.
Wired backhaul is often available in these villages, otherwise microwave or satellite could be effective alternatives.
Higher RF power small cells mounted on a pole can extend the range to 1 or 2 kilometres. This isn’t about capacity – we’re still talking about sparsely populated areas – and again this would be in otherwise outside the coverage of macrocell towers.
The wider coverage brings connectivity throughout a village and the local area.
Sometimes direct connections between these islands of communication are important. Airspan deployed their 4G solution across several neighbouring oil platforms, networked between each other to avoid satellite link delays.
Case studies from areas of Ghana, Malaysia, Indonesia and even the remote depths of the Peruvian jungle are detailed in this Small Cell Forum report.
Although geographic coverage from macrocells continues to improve, there remain areas with poor or limited service. These may be hidden within valleys or just out of range. Even where coverage exists, low signal quality translates to slow data speeds, rapid battery drain and inefficient use of macrocell resources.
Infill solutions need to work more carefully with the existing macrocells, avoiding interference at the cell edge which would otherwise introduce blind spots elsewhere.
Examples include Parallel Wireless which can relay an LTE signal into a valley and is being used by UK operator EE to extend their LTE rural coverage.
Verizon’s LTE in Rural America project is also worth a mention. This has extended LTE to many areas across the US where local rural networks install Verizon LTE equipment on their own macrocell towers and uses Verizon’s 700MHz spectrum. These are connected directly through to Verizon’s LTE core network. The local network can resell as rebrand as their own LTE service. It now serves 2.6 milion people over an area of 2.6 million square miles.
I don’t see any reason why that concept couldn’t be extended to include Small Cells, both indoor and out.
Backhaul Concentrators and Local Switching
Many of these remote areas may already have some form of backhaul. Satellite communications are becoming more widespread and viable at higher speeds as a viable solution.
In many remote communities, much of the voice and text messaging will be directly between the local population. Using local switching to bypass the satellite backhaul link would save considerable bandwidth. Innovative and low cost solutions from vendors such as Quortus are ideal in these situations.
The Small Cell Forum publishes an overall architecture (below) which includes a “Local SCN” or Small Cell Node. This can be a simple backhaul adaptor, which might optimise the data flow to make best use of narrowband satellite backhaul. Or as shown further below, it may even extend to a local EPC (Core Network) which can actively switch calls and data sessions between local users, wireline telephones and data services.
A reliable source of continuous mains power is often available, especially in more industrialised countries. The power consumption of a remote rural small cell can be less than 100W, including satellite backhaul modem.
There are several power management solutions available which actively monitor and control renewable sources (solar, wind) with storage (rechargeable batteries, fuel cells). PowerOasis and Intelligent Energy spring to mind.
As one Australian reader pointed out to me recently, they don’t have a shortage of sun for solar power in the Outback.
Bringing cellular service to rural and remote areas is very cost effective and practical using Small Cells.
There are several distinct scenarios of where and how this can be achieved described above.
Power and backhaul are also important elements, for which there are viable solutions.
Controlling on-going running and maintenance costs are important to ensure commercial viability, something a co-operative and supportive local population can help with.
Several of the examples given in this article are taken from Case Studies documented by the Small Cell Forum
The Forum has published a raft of documents covering many aspects of rural and remote small cells