Patent ID: 9736660
Date: 2017-08-15
CPC Classifications: H04L,H04W

Claim:
1. In a cellular network having a push-to-talk (PTT) system, a caller client device for initiating a PTT call to a recipient client device, wherein said caller client device is configured to: register said caller client device with a Push-To-Talk over cellular (PoC) server using an enhanced registration request message, wherein said enhanced registration request message is created by adding a binary session initiation protocol (SIP) invite in a registration request message; initiate a call set up from said caller client device with a recipient client device, wherein the call set up is embedded with a binary SIP invite message; receive a requested contact list from said PoC server, wherein each contact in the contact list is associated with a universal resource identifier (URI) and a corresponding identification number of said recipient client device, and wherein said identification number is smaller in size than said URI; and transmit said binary SIP invite message to said PoC server using a router in said cellular network.