Broadband PTT reduces LMR channel loads when the LMR/LTE integration service is strategically managed and is coordinated with public safety radio network managers.

Introduction

Broadband PTT, when properly integrated with LMR systems, provides public safety personnel the convenience of smartphones, the extended reach of LTE and WiFi networks, and affordable agency interoperability.  In addition, managed LMR/LTE integration services can improve LMR channel, tower, and backhaul efficiency, when coordinated with agency stakeholders and radio network managers.

About Tango

Tango Tango provides LMR to Broadband PTT integration services for thousands of public safety customers. Our turnkey service is simple and affordable, and it works in conjunction with our FirstNet Certified app for Apple iOS and Android smartphones. Included with our service is fully managed interoperability, allowing Tango Tango customers to connect to each other in an orderly and controlled manner.  We back all this with first class customer support and a sincere dedication to helping our customers improve their communications.

LMR Resources

Like all communication systems, LMR systems have finite resources that must be managed to ensure system reliability. Talkgroup membership must be properly sized to reduce the chances that multiple concurrent talkers clash with each other or that the channel is too busy. Total user count and transmit probabilities must be analyzed to ensure that shared trunked systems have a workable statistical model for trunk availability. Site backhaul engineering must not only account for statistical usage based on nominal users and groups, but also must factor in user roaming, mutual aid channel usage, and emergency incident situations.

For larger systems, responsibility for managing these resources often falls outside of the end user community, often to radio network managers. To be effective, radio network managers need to coordinate with users to manage the numbers of users, talk-group organization, roaming issues, and mutual aid channel policies. This may include approving new users and talk-groups and having constant visibility of system resource usage.

Broadband PTT with LMR Integration

While Broadband PTT integration may be accomplished via standardized digital interfaces, such as ISSI, many integrations are implemented using Radio over IP (RoIP). RoIP is a simple, but effective and inexpensive, method for integrating a donor radio, which is simply a radio on the target LMR network. The donor radio is connected to a gateway, which connects the donor radio audio and control signals to a broadband IP network, enabling IP connected smartphone apps to communicate with the LMR network.

Tango Tango has hundreds of LMR systems integrated with our broadband PTT service via RoIP.  Our experience, support, and process ensure that our customers’ communications capabilities are greatly improved, while maintaining the reliability and control required by public safety. Our policies and ability to work closely with radio network managers helps ensure overall success and can lead to LMR resource efficiency gains.

LMR Efficiency Improvements

Tango Tango’s radio integrated broadband PTT has no negative impact on LMR resource efficiency and in many cases can improve it.

• The Tango Tango donor radio is fixed, so incurs no LMR roaming costs if properly located.
• Tango Tango app users are managed with visibility or full control of radio network managers, via our administrative portal ConnectCare and our interop agreement service.
  • We work with each of our customers to clearly establish the administrative point(s) of contact.
  • Most Tango Tango app users are already radio users and will only use one device at a time, causing no net increase in user counts.
  • Customer admins using ConnectCare can immediately remove users from a talk group or deactivate users entirely.
• ConnectCare provides historical usage visibility, including call logs and active user counts.
• Tango Tango app users induce no added LMR usage cost when listening.
• App users who are talking do use the radio channel, but are authorized users anyway. (Unauthorized users would also be detected by dispatchers on the channel.)
• A traveling user with our app incurs no LMR roaming cost, in contrast to a traveling LMR user which does.
• Often, some app-only talk groups can replace LMR talk groups, decreasing overall trunk usage.
• Some Tango Tango customers have performed historical usage analysis and have found no detrimental impact on their LMR resources.

References

1. Public Safety Advocate: LMR, FirstNet PTT Operational Concerns, Andrew Seybold, Public Safety Advocate blog