Energy infrastructure deployment occurs within a context where there is an expectation regarding service lifetime. The process of creating civic infrastructure requires significant oversight and consideration, and aims at long term solutions. This is true for all components of the energy system - generation, transport, distribution and customer premises components. The energy system is vast, so serviceability has to be considered so that the overall components require as little manual repair and maintenance as possible. Electrical infrastructure as a whole is meant to serve for multiple decades. Like physical civic infrastructure, utilities are mandated to target long term stable communication infrastructure that serve the public interest over an extended period of time. The service lifetime of diverse components are so long that newly deployed equipment must always consider interworking with legacy deployments.
Communication components of the energy system are no exception. Some communication services were deployed decades ago and continue operation (e.g. legacy teleprotection using copper wires as telecommunication.) In general, energy system communication services are defined at the application layer (e.g. by IEC). The role of the communication service is to carry these protocols with sufficient performance (throughput, reliability, maximum latency, jitter etc.) While it is possible to change communication infrastructure while maintaining the same services, this is done gradually. The communication infrastructure components are deployed with the intention that they will serve for an extended period of time - often decades, the same time scales as the energy system components expected lifetime. If more communication capacity is needed, this is added incrementally for new services, with attention paid to reduce change for existing components operation as much as possible.
The telecommunications system standardized by 3GPP supports backwards compatibility. There is a very strong commitment to support of legacy terminals. Cell phones from the mid-90s can still operate today. At the same time, the standard moves quite quickly (from an energy system perspective) with new 'generations' every decade - using different spectrum, radio protocols and networks. With 5G, service continuity and interworking with 2G and 3G has been discontinued, except for a few capabilities (e.g. 5G to 3G service continuity.) For energy infrastructure planning purposes, the 3GPP system needs to support long (e.g. 30-40 year) service lifetimes, in which terminals will be in continuous operation. The percentage of M2M-type operational services over 4G today is very low today, compared with the use of 2G and 3G.
Some features have been developed in 3GPP to facilitate backwards compatibility at different layers of the system. For example Dynamic Spectrum Sharing (DSS) in 5G allows different 3GPP RATs to coexist in the same carrier. This can facilitate migration or preservation of legacy radio technology.
The 'deployment' use case below considers these aspects from the perspective of a utility system operator. Unlike many use cases, this takes place over years.
Volt, a publicly traded utility company, operates the electrical transport and distribution network in more than one country. Interest in and regulatory requirements for Smart Grid services grows, and with it the demand for communication services. The existing communication infrastructure that Volt has deployed will become insufficient in the future, so Volt plans for deploying additional capacity. The target is to deploy communications equipment that will operate for 30-40 years. There are many technologies that Volt could choose for infrastructure, among them 5G standards. These technologies could be the basis for the utility private infrastructure, or could be used as a service if provided through a MNO. The entire process of planning, acquisition and deployment itself takes several years, but it has begun.
Volt identifies particular communication services to be addressed with LTE access to a 5GC, completes the evaluation, approval and investment process and begins to deploy. From the time that the planning started until deployment beings, five years have elapsed.
Some components of the system are 'IoT' sensors - in the transport and distribution system. These sensors are often deployed in locations that are inaccessible, where physical replacement would be unduly expensive. The overall planning and expectation is that these terminals will be in service for 35 years. (That is 40 years since the planning process began.)
The years go by, and Volt's 5G communication infrastructure continues to function. As 8G standards emerge on the market, Volt begins to consider how to replace that infrastructure - the 5G IoT sensors and other communications equipment deployed earlier. Some of the 5G components are not going to be supported by the new communication system (including integration of the 8G network with 5G networks, for example, due to the need for greater system security.)
Volt has successfully operated their energy utility services, relying on 5G communication services, for over 35 years. They begin to deploy 8G technology fully expecting this to remain in operation until 2100.
Though not formally stated in 3GPP, successive releases and indeed changes to any release after it has been frozen, avoid incompatible changes. Any change, for enhancement, correction or simplification of the standards based system occurs only after comprehensive review and acceptance by the community of stakeholders. This expresses 3GPP standards' commitment to and emphasis on backwards compatibility.
Each generation includes comprehensive support for diverse telecommunications services. The degree of integration and service continuity offered by 2G through 4G was extensive. With 5G the compatibility has been reduced. This however does not mean that a 2G, 3G or 4G system cannot be operated at the same time as the 5G system, to maintain support for existing services. However, realistically, MNO access to spectrum and the efficient use of it, make it suboptimal for operations to maintain diverse legacy access networks. Utility equipment (routers and switches in operation) are therefore subject to different decisions to be taken by the different MNO's in the different world regions where Volt operates.