Methods and systems for call routing and codec negotiation in hybrid voice/data/internet/wireless systems

摘要

A method and system for cornmemicating information includes evaluation regarding routing of calls performed at a call control point in an ITSP and/or wireless network. A PI C identity associated with another party's preferences is acquired and sent to the call control point. The PIC identity identifies the type of the carrier network (e.g., circuit switched or VoIP) and is used to make further routing decisions. If a circuit-switched carrier is identified, the IP homing leg is terminated at the voice gateway in the recipient's HPLMN and information is sent over to the GMSC where normal, circuit-switched routing procedures. If a VoIi' earner is identified then the called user's roaming number is retrieved from the HLR, and the call is further routed directly over the IP domain towards a voice gateway at the visited network minimizing the number of transcodings. Additional transcoding steps can be avoided if a single encoding is agreed upon according to"tandem free operation" (TFO). Combining inband signaling through the telephony exchanges and out-of-band signaling in the IP network it is possible to achieve, for a mobile subscriber, one encoding and one decoding of a voice.