Software defined spectrum, anyone?

W.Webb_Over the years, mobile network operators have been steadily redefining themselves and attempting to move up the value chain. This has led to the basic network operations being seen as more of a “hygiene factor” than a differentiator resulting in varying degrees of network sharing with competitors and outsourcing of network maintenance to vendors. More recently, operators have started to look towards outsourcing the core network management through software defined networks and cloud-hosted platforms. But despite all of this, the lowest level building block – the radio spectrum has remained core to the operators and something they continue to pay billions of dollars to buy and lobby for.

Why is this? Why have operators not looked to “outsource” spectrum or to sell it to third parties in the same way that many sell off their mast sites and then lease back access? In some cases there are regulatory constraints on the more innovative approaches but in practice these can typically be overcome if there were a will. Instead, there is a mindset issue here – operators feel that without guaranteed access to their own licensed spectrum they cannot have sufficient security to invest in network deployment nor will they be able to offer any kind of quality of service. After all, mobile networks have always had licensed spectrum so surely that’s the way it needs to be….

If we look more widely than wireless, this demand for dedicated resource looks odd. UPS do not have dedicated access to roads but they manage to offer QoS on parcel delivery. Amazon does not have guaranteed access to broadband transmission capability but trades quite successfully. And what MNO does actually offer QoS anyway? Of course, MNOs do need reliable access to spectrum but if this could be guaranteed then there is no need for them to own it, or to have exclusive use of it resulting in the potential for significant cost savings.

Approaches to more flexible “shared” spectrum access are now moving close to reality. Generically these go under the name “dynamic spectrum access” (DSA) or “white space access” with variants such as “licensed shared access” (LSA) which limits the number of sharers in a band being of particular interest. LSA might allow MNOs to access spectrum owned by others such as the military on a shared basis. It might also enable them to outsource much of their spectrum ownership to the equivalent of a Crown Castle in the spectrum world and lease back the capacity they need. It might also help avoid all the problems and costs of spectrum auctions as rightly pointed out in recent viewpoints published here. A signal from the majority of MNOs that they were interested in this concept could see it advance rapidly.

But can the MNOs change the habits, literally, of a lifetime?

William Webb is an independent consultant. His latest book “Dynamic white space spectrum access” can be downloaded for free from

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