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Mobile operators have long been adding closed access small cells (typically femtocells) in homes and businesses to address poor coverage. However, a shift over the last 18 months has witnessed operators viewing small cells as the most promising approach to bolstering data capacity in their networks.
Deploying small cells to boost network capacity is not without its challenges however, particularly as it’s predicted there will be around 91 million small cell deployments by 2016, rising from six million by the end of 2012. Existing network planning and management procedures are not set up to cope with this scale of small cell deployments.
It’s time for operators to accept that they can no longer continue with a “business-as-usual” approach with their existing processes designed for macro networks. The development of new procedures for small cell deployment is crucial, but from my conversations with mobile operators, the industry is on a steep learning curve – and needs to get clued up quickly.
The challenge of meeting data demand
Operators believe the best way to meet growth in data demand is to put more and more small cells into the network. But operators lack the in-depth network intelligence to draw up a comprehensive small cell strategy and ensure their efficient roll out. If operators are to meet their own targets of boosting network capacity, time is of the essence.
Residential and enterprise cells are viewed as an established method of making small increases to local capacity, but it is the new, larger, open access cells that are now the focus to deliver serious capacity into the network and address hot spot demand. These devices have greater interaction with the macro network and operators need to be far more careful about deploying them.
Critical issues arise from deploying open access small cells to boost coverage and capacity. Once a suitable site is chosen (a non-trivial task), the roll out must meet certain performance requirements, but since the metrics around large-scale deployments are still being determined it’s questionable how operators can tell if these have been met. Finally, once a cell site is up and running, it must be managed, introducing issues on a scale that operators have not yet confronted.
Site and technology selection
The planning process for macro cells in a traditional cellular network involves selecting large sites that are typically several kilometers apart. In contrast, small cell deployments will number 10 to 50 times the macro sites needed to deliver the required hot spot capacity.
This is taking a process that worked around big installations, such as the acquisition of sites and backhaul, and scaling it 20 times. This will inevitably require increased levels of automation as the engineering teams (the people that do the planning process) have until now not been required to get lots of cells out quickly in many locations.
Many operators are still working out what their small cell strategy is. It isn’t just about identifying the best place to deploy them, but also determining the best small cell technology for a particular environment.
Operators want accurate traffic maps to identify the networks’ capacity hot spots and hence the small cell deployments required. Subscriber data collected directly from the network becomes critical. Knowing areas of poor coverage and combining that with population density maps can identify locations where service demand is not being met.
Site selection is not simply about generating a traffic map and stating “here’s your hot spot.” Network intelligence also needs to point out the “not spots” – where there is demand that the operator is not able to address, and that’s why no traffic is being seen.
How to gauge new levels of success or failure
The immaturity of large-scale small cell deployments is taxing operators who are planning roll outs, as processes are still in their infancy.
Traditional macro network deployment models involve operators paying network equipment providers for roll outs when network KPIs are met. For small cell deployments, meanwhile, operators are still trying to determine how to measure success or failure, and appear far more interested in defining this based on the impact of the small cells on the macro network.
This means measures such as determining the traffic load the small cells are taking off the macro network, how the overall network capacity is being boosted and the level of interference being introduced. Equally, when a small cell deployment is not aiding the network as expected, operators want to find out why.
Given their timetables to boost network capacity, operators will need to resolve the small cell roll out acceptance issues within the next 18 months, and bridge the yawning intelligence gap that’s currently holding them back.
The challenge of managing small cells into the future
Operators manage the cellular network based on the data feed generated by a particular vendors’ system. By introducing small cells, however, a heterogeneous network is created, comprising a mixture of vendor systems that lack interoperability. The challenge is to see all these different technologies in one view.
While basic residential femto cells provide only a narrow range of data, importantly, they do provide key functionality insights. The larger small cell technologies provide far more detailed data feeds. By modelling small cell nodes and their associated performance monitors, network analysis tools can provide a single view of all the technologies from a variety of vendors that make up the network: macro cells, small cells and Wi-Fi.
Operators are lacking a critical small cell strategy and time is ticking until the deadlines for boosting network capacity arrives. The toolkits to address the complete process for small cell deployments are readily available, from site selection and roll out right through to small cell management. By harnessing these, operators will have the intelligence to mature both small cell deployments and the infrastructure to support them, laying the foundations for long-term stability in network management.
