Inter-system handoff between wireless communication networks of different radio access technologies

A method of performing a handoff between first and second wireless communication networks of different radio access technologies, comprising:

• processing a pending call with the first wireless network implementing a first radio access technology from 3rd Generation Partnership Project (3GPP);
• receiving a first message from the first wireless network to perform a handoff to the second wireless network, wherein the first message comprises, a list of target cells in the second wireless network determined by the first wireless network to have a target cell location corresponding to a location of the wireless device;
• transmitting a search message comprising a list of frequencies corresponding to the target cells to search for in the second wireless network;
• receiving the search message and determining pilot acquisition for the list of frequencies and additional frequencies not included in the list of frequencies to produce a search result comprising the list of frequencies and the additional frequencies;
• acquiring synchronization and timing for each cell for which pilot acquisition is determined;
• exchanging a second message with the second wireless network implementing a second radio access technology from 3rd Generation Partnership Project 2 (3GPP2) to establish a new call with the second wireless network via one of the cells in the search result;
• performing a call setup procedure with the second wireless network to establish the new call;
• processing the new call with the second wireless network;
• wherein the processing a pending call and the receiving a first message are performed by a first modem processor, and wherein the exchanging a second message, performing a call setup procedure, and processing the new call are performed by a second modem processor.

An apparatus operable to perform a handoff between first and second wireless communication networks of different radio access technologies, comprising:

• means for processing a pending call with the first wireless network implementing a first radio access technology from 3rd Generation Partnership Project (3GPP);
• means for receiving a first message from the first wireless network to perform a handoff to the second wireless network, wherein the first message comprises a list of target cells in the second wireless network determined by the first wireless network to have a target cell location corresponding to a location of the wireless device;
• means for transmitting a search message comprising a list of frequencies corresponding to the target cells to search for in the second wireless network;
• means for receiving the search message and determining pilot acquisition for the list of frequencies and additional frequencies not included in the list of frequencies to produce a search result comprising the list of frequencies and the additional frequencies;
• means for acquiring synchronization and timing for each cell for which pilot acquisition is determined;
• means for exchanging a second message with the second wireless network implementing a second radio access technology from 3rd Generation Partnership Project 2 (3GPP2) to establish a new call with the second wireless network via one of the cells in the search result;
• means for performing a call setup procedure with the second wireless network to establish the new call;
• means for processing the new call with the second wireless network;
• and
• wherein the means for processing a pending call and the means for receiving a first message are independent of the means for exchanging a second message, the means for performing a call setup procedure, and the means for processing the new call.

An apparatus in a UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network (UTRAN), comprising:

• means for processing a pending call with a wireless device in a first wireless network;
• means for sending a first message to the wireless device to perform a handoff to a cdma2000 radio access network (RAN), wherein the first message comprises a list of target cells in the second wireless network determined by the first wireless network to have a target cell location corresponding to a location of the wireless device;
• means for sending a search message comprising a list of frequencies corresponding to the target cells to search for in the second wireless network;
• means for receiving a search result comprising pilot acquisitions determined for the list of frequencies and additional frequencies not included in the list of frequencies, wherein the search result further comprises the list of frequencies and the additional frequencies, and wherein the search result further comprises each cell with which the wireless device acquired synchronization and timing based on the pilot acquisitions;
• means for sending a second message to a UMTS mobile switching center (MSC) to request relocation of the wireless device to another MSC in the cdma2000 RAN;
• means for receiving an indication of a new call established for the wireless device with the cdma2000 RAN via one of the cells in the search result;
• and
• means for terminating the pending call with the wireless device.

A wireless device operable to communicate with first and second wireless communication networks of different radio access technologies, comprising:

• a first modem processor operative to perform processing for a pending call with the first wireless network implementing a first radio access technology from 3rd Generation Partnership Project (3GPP), receive a first message from the first wireless network to perform a handoff to the second wireless network, wherein the first message comprises a list of target cells in the second wireless network determined by the first wireless network to have a target cell location corresponding to a location of the wireless device, transmit a search message comprising a list of frequencies corresponding to the target cells to search for in the second wireless network and provide notification of the handoff;
• a second modem processor operative to receive the search message and determine pilot acquisition for the list of frequencies and additional frequencies not included in the list of frequencies to produce a search result comprising the list of frequencies and the additional frequencies, acquire synchronization and timing for each cell for which pilot acquisition is determined, establish traffic channels with the second wireless network implementing a second radio access technology from 3rd Generation Partnership Project 2 (3GPP2) and perform processing for a new call with the second wireless network via one of the cells in the search result;
• and
• an application processor operative to receive the notification from the first modem processor and direct the second modem processor to establish the traffic channels and process the new call with the second wireless network.

A method of performing a handoff between first and second wireless communication networks of different radio access technologies, comprising:

• processing a pending call with the first wireless network implementing a first radio access technology from 3rd Generation Partnership Project (3GPP);
• receiving a first message from the first wireless network to perform a handoff to the second wireless network, wherein the first message comprises a list of target cells in the second wireless network determined by the first wireless network to have a target cell location corresponding to a location of the wireless device;
• transmitting a search message comprising a list of frequencies corresponding to the target cells to search for in the second wireless network;
• receiving the search message and determining pilot acquisition for the list of frequencies and additional frequencies not included in the list of frequencies to produce a search result comprising the list of frequencies and the additional frequencies;
• acquiring synchronization and timing for each cell for which pilot acquisition is determined;
• establishing traffic channels with the second wireless network implementing a second radio access technology from 3rd Generation Partnership Project 2 (3GPP2);
• processing a new call with the second wireless network via one of the cells in the search result;
• wherein the processing a pending call and the receiving a first message are performed by a first modem processor, and wherein the establishing traffic channels and the processing a new call are performed by a second modem processor.

An apparatus operable to perform a handoff between first and second wireless communication networks of different radio access technologies, comprising:

• means for processing a pending call with the first wireless network implementing a first radio access technology from 3rd Generation Partnership Project (3GPP);
• means for receiving a first message from the first wireless network to perform a handoff to the second wireless network, wherein the first message comprises a list of target cells in the second wireless network determined by the first wireless network to have a target cell location corresponding to a location of the wireless device;
• means for transmitting a search message comprising a list of frequencies corresponding to the target cells to search for in the second wireless network;
• means for receiving the search message and determining pilot acquisition for the list of frequencies and additional frequencies not included in the list of frequencies to produce a search result comprising the list of frequencies and the additional frequencies;
• means for acquiring synchronization and timing for each cell for which pilot acquisition is determined;
• means for establishing traffic channels with the second wireless network implementing a second radio access technology from 3rd Generation Partnership Project 2 (3GPP2);
• means for processing a new call with the second wireless network via one of the cells in the search result;
• and
• wherein the means for processing a pending call and the means for receiving a first message are independent of the means for establishing traffic channels and the means for processing a new call.

A non-transitory processor-readable memory having instructions stored thereon, the instructions comprising:

• code executable by a processor for processing a pending call with the first wireless network implementing a first radio access technology from 3rd Generation Partnership Project (3GPP);
• code executable by a processor for receiving a first message from the first wireless network to perform a handoff to the second wireless network, wherein the first message comprises a list of target cells in the second wireless network determined by the first wireless network to have a target cell location corresponding to a location of the wireless device;
• code executable by a processor for transmitting a search message comprising a list of frequencies corresponding to the target cells to search for in the second wireless network;
• code executable by a processor for receiving the search message and determining pilot acquisition for tile list of frequencies and additional frequencies not included in the list of frequencies to produce a search result comprising the list of frequencies and the additional frequencies;
• code executable by a processor for acquiring synchronization and timing for each cell for which pilot acquisition is determined;
• code executable by a processor for establishing traffic channels with the second wireless network implementing a second radio access technology from 3rd Generation Partnership Project 2 (3GPP2);
• and
• code executable by a processor for processing a new call with the second wireless network via one of the cells in the search result.