The whole notion of small-cell architecture is gaining some significant momentum as operators map out their LTE plans. Once thought to be somewhat of an afterthought, whereby operators go back and fill in their macro coverage later with picocells, small-cell architectures may very well be in the forefront of new LTE networks because they are capable of providing higher capacity, greater data throughput and indoor coverage.
Hence, the notion of a heterogeneous network, Het-Net for short, is coming to the forefront. The idea is to use multiple network layers--macro and small-cell--to improve user data rates and network spectral efficiency. It's a story about bringing users closer to a cell site. The bigger the cell site, the less capacity available per user. Of course, WiFi and femtocells are already leveraging this concept, but they are scratching the surface in terms of their integration with the macro network. For LTE, the 3GPP is focusing on making smaller cells part of the overall architecture and vendors are busy filing patents around this notion.
Wireline and wireless switching vendor Taqua recently announced it is branching out into the wireless backhaul market by proposing a new platform that can be used in new cellular topologies that that may include picocells, outdoor femtocells and WiFi hotspots. Rather than replacing the backhaul network, the platform would function as a last-mile extension for backhaul linking up remote sites.
During a recent webinar I moderated about how carriers can protect their 3G investments, Ricky Watts, CTO of Aircom, a network advisory firm, indicated that LTE networks could very well start out as small-cell networks in a sea of HSPA coverage. "Operators are looking to use technology as a competitive advantage," he said. "In terms of IP services, real-time services may be one of the inflexion points in terms of demand. "
Aircom is doing a lot of work in terms of small-cell technology and how it evolves from a femtocell solution into a home-gateway type of function and integrates with the macro network, Watts said.
What will be interesting is how picocells, femtocells or a product like SpiderCloud's enterprise radio access network, fill the demand for small cells. Will operators, for instance, be deploying a network of picocells in hotspot areas?
Of course, this is all in its infancy, and it's interesting to note that just as we'll likely see a hodge-podge of macro cells, small cells and WiFi, for instance, we'll begin to see a mix of spectrum being used to also address coverage and capacity. Jon Hambidge, chief marketing officer with IPWireless, which recently made a deal with LTE chipmaker Altair to develop a series of multi-band modem products, said operators are beginning to understand that their LTE networks will likely consist of at least two different frequency bands: a lower frequency band such as 800 MHz and 700 MHz to address broad coverage and a higher frequency band such as the 2.5 GHz or 2.6 GHz band to offer higher capacity coverage in data usage hot spots. That also means a combination of FDD and TDD LTE networks to.
In a world where mobile broadband is now the key differentiator, operators need to throw out as many solutions as possible to keep up with demand and meet subscriber expectations. In the end, networks won't be so clean anymore.--Lynnette