When we talk about the need for network densification, just how dense do networks need to be? And how can densification be achieved in busy urban areas where site space is hard to find? And how can performance be assured as the network becomes more complex? And what technologies will be future-proof and worth investing in?
And, and, and…
The questions facing operator technical departments seem never-ending as they work to deliver the infrastructure that will capitalize on potential new revenue opportunities identified by their business segment managers.
Let’s tackle the first question – how dense do networks really need to be? Nokia looked at the growth in demand facing one operator in a very busy US city. In 2014, traffic density was around 1 Gbps/km2 and was served by an average 20 macrocell sites per km2.
By 2017, traffic density hit 4 Gbps/km2. The operator simply adds 40 outdoor small cells and 50 indoor small cells per km2 to the network. Deploying relatively few small cells allows the operator to meet quadrupled capacity and coverage demand, both indoors and outdoors.
Let’s project these figures forward. By 2025, the operator will need a very dense network to support a ten-fold increase in traffic density. With no scope for deploying more macrocell sites and upgrades to macrocell base stations unlikely to meet the demand, even this extreme density can be supported with the help of small cells. Now we are looking at 150 outdoor and 500 indoor small cells deployed per km2, keeping to the intial 20 macrocell sites. Over the period covered by the study, the average inter-site distance plunges from 240m to 82m – a figure impossible to achieve without small cells.
The most obvious advantage of small cells is their compact physical size. They can be deployed unobtrusively to meet city regulations, giving the network a rapid, yet low cost boost in performance. Not only do they provide much-needed extra capacity and improve indoor coverage, but small cells can aid network balancing by off-loading traffic from the surrounding macrocells. Deployments have shown that, after deploying small cells, some macrocells stay above 60% average RF usage, indicating there was substantial unserved traffic with the macros alone.
As well as providing outdoor coverage and capacity densification across the urban area, there are many other scenarios in which small cells improve the customer experience, from boosting capacity in hot zones to improving performance at mass events.
Yet another situation could be to improve the customer experience in high traffic indoor locations such as airports and train stations, with a focus on heavy traffic areas such as check-in desks and gates. There may be an existing distributed antenna system that lacks the capacity needed or cannot support new frequencies. Small cells provide the solution – existing backhaul systems, for example re-using the Ethernet backhaul or nearby Wi-Fi AP, can be reused, cutting investment needed. The small cells can be running in days, contributing to roaming revenue and in one installation, small cells paid for themselves within a day through the increased income generated.
Outdoor small cells can also significantly boost indoor performance. In one recent case, Nokia Flexi Zone Small Cells significantly increased indoor coverage, leading to more than four times improvement in downlink and uplink throughput, generating more than 75% extra traffic per day.
An operator’s technical department faces many challenges, but with small cells, they can go a long way to meeting them.
Check out our Small Cells website for more info.
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