SK Telecom and Nokia make big cells and small cells play nice

SK Telecom has just incorporated a tongue-twister of a technology into its Nokia-built LTE network in Gwangju, South Korea. It’s called Enchanced Inter-Cell Interference Coordination, or eICIC for short, and its aim to make networks packed with all different sizes and shapes of cells work in harmony.

What [company]SK Telecom[/company] and [company]Nokia[/company] Networks claim to have done is produce the first commercial cellular heterogeneous network, or hetnet, in which a bunch of tiny little cells mounted on utility poles or on building walls transmit under the umbrella of a big tower-mounted macro-cell. Normally in that type of situation you’d get a murky soup of cross-interference, as the big cell’s signals would overwhelm the signals of the smaller cells or vice versa.

With eICIC, though, the network can coordinate how and when those cells transmit in order to prevent much of that interference from occurring. eICIC is a key component of that grab bag of technologies we’ve come to know as LTE-Advanced and it will be critical in building super-dense networks of the future with loads of broadband capacity.

A diagram from Qualcomm showing small cells under the umbrella of a macro-cell

A diagram from Qualcomm showing small cells under the umbrella of a macro-cell

SK has actually been tinkering with the technology for some time – I first spoke to the carrier’s engineers about their lab eICIC lab test back in 2011 – but it’s proven a very difficult LTE-Advanced technology to master. Interference has always been the bane of RF engineers’ existence because the more transmission points you put in the network, the more places you create overlap between those transmissions. And everywhere you get that overlap you get interference, bad signals and crappy data connections.

Instead of trying to avoid that overlap, the hetnet takes the problem head on, depending on technologies like eICIC to get them out of its interference bind. SK says it’s now ready to start spreading its hetnet across South Korea with the help of eICIC. Hopefully that means the rest of the mobile industry is ready to follow in its footsteps. If carriers can eliminate – or at least mitigate – the interference problem of small cells, we could start seeing networks that don’t get overloaded in crowded places and pack tremendous amounts of capacity.