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Cellular to 802.11 voice roaming utilizing SIP signaling

  • US 7,215,959 B2
  • Filed: 12/15/2003
  • Issued: 05/08/2007
  • Est. Priority Date: 12/15/2003
  • Status: Active Grant
First Claim
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1. A method of roaming between a cellular network and a wireless network comprising the steps of:

  • receiving an invitation over the wireless network, wherein the invitation is sent from a mobile communications device engaged in a cellular call over a cellular voice channel;

    authenticating the mobile communications device over the wireless network;

    sending an acknowledgement of the invitation to the mobile communications device over the wireless network;

    comparing the strength of detected signals from both the cellular network and wireless network; and

    initiating a handoff based on the comparison, wherein the established cellular call is switched from the cellular network to the wireless network, and wherein the mobile communications device determines based upon the comparison to effect the handoff and operates to attenuate a signal transmitted from the mobile communications device to the cellular network thereby causing the cellular network to effect the handoff.

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