- Macrocell towers are the giant towers that we all know. They have the largest range around, and are often seen in rural areas.
- Microcells have a range of under one and a quarter miles (two kilometers), and have been the go to cell station for urban areas.
- Picocells, have an effective range of under 650 feet (200 meters), and are often used indoors like malls, train stations, etc.
- Femtocells, which have a range of around 33 feet (10 meters), and they are used in offices or homes. Although, confusing the issue, AT&T has branded its home/office wireless signal boosters as 3G Microcells although they are technically femtocells.
Small cell stations aim to build stronger, faster networks; Sprint the first with open plans
Smartphones drive data. It's a fact that's inescapable to wireless carriers and one that they have been searching for the answer to. Next generation networks like LTE are designed to handle big data, but it's the small cell stations that will make up the network that could bring the biggest benefit. We've heard the tales of trouble from every major carrier in the US about the cost and difficulty of building out new networks, and usually we just talk about the troubles of acquiring the radio spectrum needed to provide the bandwidth, but we almost never stop to consider the hardware used to deliver that bandwidth.
Since cell phones started really making the move into the mainstream, we've been watching as cell radio towers go up all around the country, trying to blanket as much space as possible with signal. And that really was the idea: big towers can throw big blankets and cover a lot of space. The trouble with that idea is that when you get to more crowded areas, there are more points for interference because everyone is tossing blankets of signal all over the place. If the towers aren't spaced correctly, there will be random dead-zones, and thin spots where signal can be tricky. Also, when you are using fewer towers to spread large amounts of signal, it is far easier for a tower to be overloaded because each needs to do more and more work.
The new idea is to go smaller. Small cell stations aim to be the solution to these issues, and when we say small cell, we mean really small. Like, some the size of a Rubik's Cube or a USB thumbstick. But, what they lack in size, they make up for in sheer numbers. So, instead of a few big towers covering an area, there will be hundreds or thousands of small cell stations. The small cells could weave a much tighter network, and on top of that, they could be placed inside buildings to help increase reception. In fact, some small cell stations are already in use in some subway systems around the country.
The trouble with "small cell" stations is that there are actually a bunch of different technologies that all get bundled under the same category, and each technology has different pros and cons. So, just saying that a carrier is deploying "small cell" stations isn't really enough.
In general, microcells and picocells can be anywhere in size from about the size of a cabinet to around the size of a briefcase, although last year Alcatel-Lucent premiered the aforementioned Rubik's Cube sized picocells called lightRadio. Femtocells have evolved to the point where they can be implemented in a simple USB thumbstick. This small size means that not only can the devices be hidden from view, but they can be installed quickly and easily in many common places like street lights or utility poles. This is a big boon for carriers, because the cost of installation can be offloaded to reduce costs.
By creating a dense network of small cell stations (a combination of mostly microcells and picocells, though sometimes femtocells make it into the mix), carriers can create networks that have better reception, less interference, fewer dead spots, and faster data speeds. All carriers are working on adding small cell stations to their networks, but Sprint has been the first to really lay out the plans.
Don't misread this. Sprint is likely not the first carrier to implement the use of small cell stations to bolster network performance and coverage, every carrier is working on this, but Sprint is the first to openly explain its plans as it did at CTIA. Most telcom analysts say that by 2015, 90% of all cell station deployments will be made up of small cells. And, this kind of rollout may be just enough to stay ahead of our mobile data needs, because Cisco's newest Mobile Visual Networking Index, one of the more complex and respected studies around, is predicting that by 2016 over half of all Internet traffic will be through mobile devices, and 71% of that traffic will be video. Of course, that may not mean that the Internet traffic is going to be on mobile networks, but WiFi is actually a part of the small cell build-out. Carriers are all looking for ways to offload traffic, and having a network of small cell stations can help that because some low-powered devices can also be WiFi hotspots. AT&T has been using this strategy for years.
Sprint put forth its small cell plans at CTIA, explaining that the company is planning to build a HetNet. That sounds pretty fancy, but really it just means a heterogeneous network, which originally was used to reference a LAN network that had Windows, Linux and Mac all on the same network. Now, the term has been shortened and jazzed up for marketing, and a HetNet specifically means using a mix of macrocell base stations with small cell stations when building a cellular network.
Sprint's plan has 3 phases and include installing tens of thousands of small cell stations over the next 2 years. This year and next, Sprint will focus on installing femtocells in homes, businesses, and indoor public areas. Next year will start the big rollout of picocells in high traffic indoor spaces, and big public venues. Specifically, this will mean installing between 100-200 small cells in as many as 400 public venues like stadiums, airports, conference centers, etc. Then, in late 2013 and into 2014, Sprint will be focusing on dense outdoor areas like city centers.
The ultimate plan for Sprint is to build a layered network where the macrocells provide large areas of coverage, and small cells can handle the demands of dense areas. This seems like a reasonable plan that most carriers would also be following to an extent. If all goes according to plan, Sprint should have a pretty solid LTE network in place by 2014. The only question would be how many customers Sprint will have for that network. However, if Sprint decides to license its LTE network to smaller carriers like Boost Mobile, Virgin, and Ting, as it has with its CDMA network, that could put a pretty powerful network in the hands of carriers looking to disrupt the standard carrier system and lead to cheaper plans. It's a nice dream at least.
We're looking forward to hearing more clearly laid out plans from other carriers about how each is planning to implement small cell stations, and the installation timelines. Having a coverage map that has as few empty areas as possible is no longer the only goal. Carriers have to be building networks that can handle huge amounts of data in densely populated areas without having bad reception or dropped calls.