Through a mixture of hardware and software a Convergence (Unified Critical Communications) platform can be implemented in various ways, either as a centralized system hosted on customer premises or as a cloud-based service, or de-centralized as a mobile platform connecting voice and data networks, with Internet access to an organization’s home network via LTE broadband.

Without getting into the design details of specific products, we can identify some common features of current UCC platforms

The basic idea is to create a network of networks through LMR, LTE broadband, WiFi and Bluetooth and any other supported technology (e.g. satellite). Open standard IP protocols provide much of the essential glue.

A UCC platform interconnects all these different bearers, enabling any device to interoperate with any other device in the system. So, services and applications available on each technology can become available to everybody.

A perfect example is Push-to-Talk over cellular, which allows users of smart devices (whether Android or Apple, smartphone, tablet or laptop) access to LMR services such as individual and group calls. And it works the other way, too: LMR users can make calls to these cellular devices.

One consequence is that a group call can span multiple technologies and multiple devices. The talkgroup is defined to include users of different devices.

To manage all the users and devices on this network of networks, the UCC platform provide a means of adding, storing, and removing device-independent user IDs. Each user ID will have associated information about groups they belong to, group affiliations, access rights etc. Since groups may need to be created or changed on the fly, there will also be a database for managing groups.

For critical communications to operate without a hitch, the administration of user data and group membership needs to be kept up to date, with any changes made instantly, such as through Over-the-Air Programming (OTAP) which can re-program a fleet of devices remotely over the air.

When you logon to a UCC network with your user ID, several things happen. A registration process begins which includes an authentication check by the network against a database of permitted user ids, an authorization of access to permitted services, a logging of your entry to the UCC network, the detection of your current location, and an advertisement of your presence on the system as available for communications.

Security is mandatory for critical communications, so these checks are a central element of a UCC platform, which must also provide end-to-end securing of voice and data transmissions, a facility for call recording and logging, as well as accounting of any other communications activity on the network.

So, a UCC platform must maintain and merge the bearer connections, manage users and groups across various devices, arbitrate cross-network calls, and provide essential security coupled with audit services. Surprisingly, all this does not require a lot of hardware. At its most compact – for instance, Tait Unified Vehicle – a unified critical communications platform can fit into the space of a car radio.