There is an old saying, "If the only tool you have is a hammer, you will start treating all your problems like a nail.” This quote dates back to 1964 and Abraham Kaplan, whose first wording was actually, "Give a small boy a hammer and he will find that everything he encounters needs a pounding." Abraham Maslow modified it in 1966 to, “If all you have is a hammer, everything looks like a nail," which is why we commonly refer to the concept as “Maslow's Hammer” in reference to over-reliance on a familiar tool.
If you are lucky enough to be the parent, aunt, uncle or other relative or friend of a small boy with a runaway hammer - you can probably relate!
Over the years, I have found myself in this situation, taking the tools or approaches that served my needs very well in the past and trying to force them to be the right solution for my newer challenges or problems.
In today's mobile network expansion, the conversations around "small cells" is a great example of a situation where we might need hammers, but we might also need wrenches, screwdrivers and a whole host of other tools in the tool kit.
A good approach to small cells is to start with the root cause of the problem and then assess the most appropriate tools for each application. In my view, the heart of the small cell conversation is like Maslow’s Hammer. If all you have is a small cell, then everything looks like a small cell application.
But if you step back to see the bigger problem—namely, how network operators can extend capacity through densification while overcoming the obstacles of space availability, site acquisition, power and backhaul availability, and all at a performance level that justifies the investment—then there are a host of tools that can be considered.
Solutions to the network densification problem include:
- Increasing the capacity efficiency of existing "hot" macro sectors using common techniques like carrier adds, RF optimization and more specialized techniques such as sector splitting or implementation of MIMO technologies.
- The application of "mini macros" or macros with a "shorter" antenna above ground height with fairly standard remote radio head technology but typically engineered to fit into a cylinder shape for easer concealment and zoning approvals.
- The use of distributed antenna systems (DAS) to extend capacity and coverage in both outdoor and indoor applications where a multi-frequency, multi-technology and multi-operator application is the best fit for the application.
- The use of small, low power radio access nodes covering distinct areas such as hot spots.
Selecting the right tool then becomes a matter of evaluating each application and assessing future state requirements. The former is pretty straight forward, the second one - not so easy.
On the application side, I tend to think about four key considerations:
- What is the size of the capacity problem, meaning, how many users, in what space and at what quality level do we need to support?
- What are the physical considerations of size, architectural and regulatory constraints and provisioning for backhaul and power?
- What are the implementation challenges of investment expenses, solution maturity and time to deployment?
- What are the quality challenges of interference mitigation, network interoperability and optimization?
As far as predicting the future state needs - let's say there will be “more.” Not more as in Moore's Law but more like in Cooper's Law of Spectral Efficiency. Cooper’s Law states that the maximum number of voice conversations or equivalent data transactions that can be conducted in all the useful radio spectrum over a given area doubles about every 30 months. I suspect that we are accelerating faster than that today, an evolution of application and technology that was unforeseeable at the time. How much faster can that increase? We shall see.
In our LTE Best Practices ebook, we put together some of our observations about a whole host of the LTE implementation challenges for many applications. In chapter 10, I cover small cell applications in more detail and outline a few key best practices with respect to equipment selection, environmental and installation practices. I hope you will find the ebook useful as you select and deploy the right hammers or, even better, the right tools at the right time.