It's no secret that 4G Long Term Evolution () networks will be fundamentally different from today's circuit-switched variations. The fundamental difference, of course, is an all-IP network, but these networks also will come with the requirement that significantly more need to be deployed to get the coverage and high-speed data speeds the technology advertises.
"4G networks will be characterized by many smaller cells," said Yan Hui, founder and CEO of AirHop Communications, a new software player in the LTE space. "It's not going to be a macrocell-dominated network. It will be dense, with a lot of overlap and different tiers."
Such a deployment scenario can create all sorts of havoc for an operator in terms of the expense required to construct the network and manage interference. This is why the LTE standards body, the Third Generation Partnership Project (), has come up with the concept of self-organizing network (SON) features that are, in general terms, designed to reduce operating costs and optimize performance.
SON refers to the ability of LTE networks to self configure, self operate and self optimize themselves throughout their life cycle, thereby reducing the operational expenditures of LTE networks. For instance, LTE cell sites can be connected and optimized automatically rather than on a manual basis. The Next Generation Mobile Networks (NGMN) Alliance and the 3GPP have standardized SON with an eye on decreasing the associated opex with rolling out and managing LTE networks.
In the beginning, LTE's SON features will be applied in base stations, but they are not restricted to the radio-access network and will ultimately reach further into the network. All of the major infrastructure vendors in the mobile industry — Motorola,and Ericsson, to name a few — have SON strategies. And most are focusing on first reducing the cost of installation of LTE networks, as the earliest features of SON will make it possible to build plug-and-play base stations that self configure at installation and automatically detect neighboring cells when activated. This feature will reduce the manpower required to install the equipment and reduce the amount of time to set up base stations.
Later, however, SON will dig deeper into the network, offering more advanced optimization and performance-management features, given the fact that LTE cells will be smaller and denser. This is where AirHop Communications sees itself playing. Its eSON technology is designed to extend SON well beyond this initial set-up phase to include distributed, real-time, inter-cell coordination capabilities that lets neighboring base stations communicate with each other to dynamically manage interference, data throughput and QoS, as well as optimize frequency reuse.
Yan said how quickly LTE operators use smaller cells depends on the carrier. Verizon Wireless, which is deploying LTE in the 700 MHz band, likely will deploy larger macrocells initially. European operators dealing with higher frequencies will have to deploy smaller cells from the beginning. In the end, however, if operators, including public-safety operators, want to provide coverage in the high-density urban areas, they will need to deploy these denser, smaller cells earlier. Yan said network operators estimate that about 80% of high-speed data traffic will occur in dense urban areas.