Long Term Employment for whom?
 
We sometimes joke about what LTE really stands for. Among the many possibilities that the letters L, T and E offer, the phrase Long Term Employment has been brought up more than once. I sometimes wonder who is going to enjoy this long term employment really? The way I see it, unlike its counterpart in the Nature, this long term Evolution seems to be heading in the wrong direction. It is going to put us all out of work!
 
Consider one of the most ambitious features in LTE, namely the Self-Optimizing and Self-Configuring Network or SON for short. This is the idea in a nutshell: The radio network manager flips a switch on her desk and the entire access network comes to life. Evolved-NodeBs start warming up, they will then begin to look for their neighbors over the X2 interfaces and initiate the handshaking with the EPC over S1. They configure themselves and each other with network parameters, software downloads and soon start broadcasting on PBCH.  Some of the towers are actually on wheels (as in COWs: cells on wheels) and start moving around autonomously to adjust for the clutter and changing environment. Moments later the handsets are communicating with the network, beams are formed, multiple antennas are electrically tilted, power amplifiers are adjusted, and millions of subscribers unbeknownst to them, become sources of input data to a self-optimizing network that now has a life of its own.
Meanwhile the two RF engineers downstairs are engaged in a game of tennis on wii and the field technician is on page 512 of 'War and Peace'. SON of LTE has arrived! What am I going to do next? I can almost hear the shrill voice in my head “Get your own LTE network and stop whining”.
 
Ok, I admit to a slight element of exaggeration in my scenario, but be forewarned that SON has passed the dream stage and is part of stage2 3GPP specifications now!  So we need to understand what the real motivation behind SON is. I have identified 3 main driving factors for the development of SON. (Send your comments about more that I’m sure have been overlooked.)
 
1. OpEx:  As a wise man (down my corridor) says, the real LTE killer-app is the reduced cost of operations (OpEx) for the carriers. Obviously a self do-it-all network is an important step in giving more weight to this wisdom. SON can become a central feature of LTE and an interesting differentiator for vendors who are early adopters of the ambitious program.
 
2. HeNB: How about Home-eNodeBs, aka femto-cells? I refuse to fly back all the way to Sweden to configure my mom’s LTE femto-cell. A femto-cell that you just picked up at the local Best Buy should be plug-and-play, period. Therefore, there is little doubt that SON will play an important role in this arena. It may be true that the scope and complexity of a femto-cell will not match that of a full blown eNodeB in the field and many femto-cells may come with a lot of preconfigured parameters, but the HeNB must sooner or later get an IP-address, authenticate the network and be authenticated and is likely to download certain software/firmware before it does you any good.
 
3. Plectics: Finally, I can also see a case for the grand Self-Optimization part of SON. Ever heard of complex networks and emergent phenomena? If not then try this experiment at home. Plant five termites in your garden and watch what happens. Not much I bet. Next, try 5000 termites and watch the magic show. A super-organism will emerge with an intricate network of functions and behavior that would soon want to devour your entire house. (For a less expensive insight to network complexity and emergent behavior, I recommend M. Gell-Mann’s “The Quark and the Jaguar” or just google the odd word “Plectics” if you have not already done so).

It is no secret. Telecom engineers have known that a network can be larger than the sum of its parts, somewhat akin to a termite colony. Grant that a wireless network is orders of magnitude simpler than a termite colony, but it still has thousands of components that must inter-operate flawlessly. Wireless networks are notorious for becoming unstable under certain conditions, such as shifts in traffic patterns. Pin-pointing a solution can be a difficult task. You change a parameter here, and something else happens over there. You change another parameter there and nothing happens. With literally hundreds of network parameters to play with, it is easy to feel frustrated as you note that the performance indicators are not where they need to be. In my experience with operators and their attempts at optimization, the rule of thumb is to follow ‘common practice’. Do what was done in the past and and don’t touch anything if you are not sure of the outcome! There is little or no room for experimenting here. Moreover, a speedy response to localized problems in the network requires a very good understanding of how the network performance metrics are influenced by the relevant parameters at any given time. You need intelligence and adaptive behavior in a network to deal with these issues and the RF engineers have been kindly providing most of that so far.

SON has the potential to bring a radical change to the way we approach problems in the radio network. It combines a fast response time, with the intelligence of self-optimizing algorithms to predict, avoid and solve radio network problems instantaneously.

My exaggerated scenario in above is not going to be realized any time soon, (self-moving COWs was a joke, seriously :-) but I have no doubt that the self-optimizing feature of LTE networks will provide a crucial advantage as a tool for tackling the complex problems of RF performance. Yes, we still need RF engineers to be in charge for forseeable future.
 
In the sequel, we will take a closer look at the SON features of self configuration and optimization and explore the role of the UE as described in the standards.
 
Later,

/Hooman