Interworking Internet telephony and wireless telecommunications networks

Internet telephony and mobile telephony are both growing very rapidly. Directly interworking the two presents significant advantages over connecting them through an intermediate PSTN link. We propose three novel schemes for the most complex aspect of the interworking: call delivery from an Internet telephony (SIP) terminal to a mobile telephony (UMTS) terminal. We then evaluate the proposals both qualitatively and quantitatively. However, existing equipment may not support packet interfaces needed for such interworking. Therefore, we also consider techniques for backward compatibility, and analyze their performance as well.