MVM NET, member of 450 MHz Alliance, plans to introduce its PTT (Push-to-Talk) service on its LTE 450 mobile network for a long time. During this period, they have tested several systems. Eventually it was NKM’s – National Utilities Ltd (the national utility service provider) – demand that made it happen. They intended to replace their trunked FM radio system for voice. Following preliminary tests Tassta’s system was chosen. Since they do not manufacture handheld terminals, RugGear’s model RG760 was accepted.

The service is being introduced in two phases. In the first phase MVM NET wishes to find a solution to serve NKM’s need during the period while their on-premise server is being deployed. Tassta’s Cloud based PTT solution has been proved capable of covering this period.

Services and features offered by the Tassta Cloud based PoC System are the following:

  • emergency group call
  • private call (point to point call)
  • PoC user initiated group call
  • Dispatcher/operator initiated group call
  • Dispatcher/operator initiated private call
  • Text message transfer to group and individuals
  • File transfer to group and individuals
  • Optional: PoC user on regular PoC UE with dispatcher role
  • Optional: ambient listening (remotely / locally initiated)
  • Optional: man down sense (lone worker protection, depends on UE type)

The estimated time of the commence of the Tassta Cloud Service is September 2020.

As for the final solution, the PTT platform, which runs in MVM NET’s own server environment, will be introduced in the near future. Due to a higher level of SLA they are going to build geographically redundant servers, which will be controlled by an arbitrator entity. The arbitrator is responsible for monitoring the primary server and switching the communication environment to the secondary server in case of any issues arising with the primary server. Between the two servers they will build a redundant connection. To the previously mentioned feature list two other items will be added, which are the following:

  • video private call
  • video group call

As for the voice recording, there will be one-on-one recorder server at each spot. The voice files will be synchronized between these servers due to the higher level of data protection against loss. The main properties of the voice recording solution are as follows:

  • automatic (pre-defined) centralized voice and video recording
  • playback of recorded speech
  • 24/7-hour access to voice files
  • recorded speech will be searchable

The dispatcher workstations at client side will be directly connected to the PoC system via L2 leased lines.

MVM NET’s PoC network and its services will fulfill requirements for “non-mission critical Push To Talk service” described in 3GPP 22.179. Their long-term plans include reaching the mission-critical level with their PoC system.