Thursday, December 12, 2013

FirstNet and the Public Safety Broadband Network - an analysis of Dynamic Spectrum Arbitrage?

Dynamic Spectrum Arbitrage for FirstNet?

In order to get a feel for what “Dynamic Spectrum Arbitrage” is lets take a look at the patents Abstract below: (ref: Patent application title: Methods and Systems for Dynamic Spectrum Arbitrage. 20120014332)

Methods and system are provided for managing and monitoring allocation of RF spectrum resources based on time, space and frequency. A network may be enabled to allocate excess spectrum resources for use by other network providers on a real-time basis. Allocated resources may be transferred from one provider with excess resources to another in need of additional resources based on contractual terms or on a real-time purchase negotiations and settlements. A network may be enabled to monitor the use of allocated resources on real-time basis and off-load or allow additional users depending on the spectrum resources availability. Public safety networks may be enabled to make spectrum resources available to general public by allocating spectrum resources and monitoring the use of those resources. During an emergency, when traffic increases on a public safety network, the public safety networks may off-load bandwidth traffic to make available necessary resources for public safety users.”

Ok, who wants to be the first Ginny Pig on this? This is the issue with this theory, let alone the fact that it's still a theory. This doesn’t discount the idea that the theory won’t work, or is invalid, this just asks the question as to who wants to be first to deploy the technology; then wait a few years for a standard to be produced; then commit to a vendor negotiated procurement process for the best solution? It may be just me, but wouldn’t that take a lot of time away from getting the Public Safety Broadband Network built?

It is a written requirement within the legislation that FirstNet must utilize “Commercial Off-the-Shelf Technology” -- or COTS for short. The reason being is that we don’t want to deploy a network that is bleeding edge; we require a network that is on the leading edge.  This means the technology must have a proven and standing track record in order to be deployed.

Plus, here’s the thing, why would we consider dynamic allocation of spectrum anyway? The LTE technology can, in effect, deliver Dynamic Bandwidth Allocation (DBA), which has been a proven technology for many years. Just seems like wasted time and money. You can look at any Wave Division Multiplexing device, or Ethernet Transport solution, and see DBA at work. Basically, it see’s the spectrum as a big pipe and allocates traffic in the packetized environment over QoS (Quality of Service) or CoS (Class of Service)  tagging protocols, but that’s just me getting my techie on. I would not expect that a radio engineer would understand the packetized solutions as they were designed.

Dynamically allocating spectrum is a technology that would have prospered 40 years ago, but today we have moved beyond and up the protocol stack towards bandwidth allocation utilization, plus, it allows us to better prioritize traffic across multiple users, or virtual managed networks, especially as we connect to cloud based services. You should note that as the LTE network gets deployed, all of its users, i.e. Police, Fire, Utilities, transportation, essentially would have their own Virtual Private Network running over the bandwidth that LTE delivers. Trying to prioritize each user based on available spectrum will be tedious at best. For the COTS available Public Safety Broadband Network this is how the LTE Core will manage its user base for prioritization, much easier than being a test-bed for a new theory in RF technology.

Excerpt on Dynamic Bandwidth Allocation: (Wiki)

"Dynamic bandwidth allocation is a technique by which traffic bandwidth in a shared telecommunications medium can be allocated on demand and fairly between different users of that bandwidth. This is a form of bandwidth management, and is essentially the same thing as statistical multiplexing.[disputed – discuss] Where the sharing of a link adapts in some way to the instantaneous traffic demands of the nodes connected to the link.

Dynamic bandwidth allocation takes advantage of several attributes of shared networks: (1) all users are typically not connected to the network at one time (2) even when connected, users are not transmitting data (or voice or video) at all times (3) most traffic occurs in bursts -- there are gaps between packets of information that can be filled with other user traffic 

Different network protocols implement dynamic bandwidth allocation in different ways. These methods are typically defined in standards developed by standards bodies such as the ITUIEEEFSAN, or IETF. One example is defined in the ITU G.983 specification for passive optical network (PON)."

But then again….

I’m just some guy and a blog….

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