Determining probability of successful push-to-talk call connection

A push-to-talk (PTT) system comprising:

• a first PTT device including a user interface, a memory storing a list of contacts, and a device electronic processor;
• and
• a server including a server electronic processor configured to
• receive, from a second PTT device that is included in the list of contacts, a disconnection status of the second PTT device, the disconnection status indicating a disconnection of the second PTT device from a communication network and including a disconnection timestamp,
• receive, from the second PTT device, a re-registration status of the second PTT device with the server, wherein the re-registration status indicates a connection of the second PTT device to the communication network and includes a re-registration timestamp,
• determine an online status of the second PTT device based on the re-registration timestamp,
• determine a time difference between the re-registration timestamp and the disconnection timestamp,
• determine a probability of the first PTT device establishing a successful PTT call connection with the second PTT device based on the re-registration status of the second PTT device, the online status of the second PTT device, the disconnection status of the second PTT device, and the time difference between the re-registration timestamp and the disconnection timestamp, and
• transmit the probability to the first PTT device;
• wherein the device electronic processor is configured to
• in response to receiving the probability, display an indication of the probability on the user interface.

A method for determining a probability of successful establishment of a push-to-talk (PTT) call connection between a call-originating PTT device and a target PTT device, the method comprising:

• receiving, from the call-originating PTT device, a list of contacts stored by the call-originating PTT device;
• receiving, from the target PTT device that is included in the list of contacts stored by the call-originating PTT device, a disconnection status of the target PTT device, the disconnection status indicating a disconnection of the target PTT device from a communication network and including a disconnection timestamp;
• receiving, from the target PTT device after receiving the disconnection status, a re-registration status of the target PTT device, wherein the re-registration status indicates a connection of the target PTT device to the communication network and includes a re-registration timestamp;
• determining an online status of the target PTT device based on the re-registration timestamp;
• determining a time difference between the re-registration timestamp and the disconnection timestamp;
• determining a probability of the call-originating PTT device establishing a successful PTT call connection with the target PTT device based on the re-registration status of the target PTT device, the online status of the target PTT device, the disconnection status of the target PTT device, and the time difference between the re-registration timestamp and the disconnection timestamp;
• and
• transmitting the probability to the call-originating PTT device, wherein reception of the probability by the call-originating PTT device causes a user interface of the call-originating PTT device to display an indication of the probability.