Patent ID: 8406799

Claim:
A method for establishing an inter-radio frequency subsystem interface (ISSI) group call through a hosted ISSI function (HIF) device and between a home radio frequency subsystem (RFSS) and at least one serving radio frequency subsystem, the method comprising: maintaining, at the HIF device, a list of affiliated RFSSs, wherein the list identifies the at least one serving RFSS; transmitting an affiliation request, from the HIF device to the home RFSS, wherein the home RFSS is a home RFSS of a group; receiving, at the HIF device from the serving RFSS, a request to initiate an inter-RFSS group call to the group using HIF addressing; transmitting, from the HIF device to the home RFSS, a request to initiate the inter-RFSS group call using serving RFSS addressing; receiving, at the HIF device, a data packet from the home RFSS or the serving RFSS; and transmitting, from the HIF device to the serving RFSS, a copy of the data packet if the data packet was received from the home RFSS; otherwise, transmitting, from the HIF device to the home RFSS, a copy of the data packet if the data packet was received from the serving RFSS.