Method and apparatus for detecting an alternate wireless communication network

A method for selecting an alternate wireless communication system for a wireless communication device is disclosed. The method comprises using a first radio access technology (RAT) by a wireless communication device when scanning (202) for an initial wireless communication network (201). The wireless communication device further registers (215) to the initial wireless communication network (201). Then, the initial wireless communication network (201) determines (206) alternate RAT wireless communication network information for the wireless communication device and sends (235) the alternate RAT wireless communication network information to the wireless communication device. The wireless communication device receives the alternate RAT wireless communication network information and selects (240) a first alternate wireless communication network from within the alternate RAT wireless communication network information, scans for the first alternate wireless communication network using an alternate RAT and registers with the first alternate wireless communication network using the alternate RAT.

FIELD OF THE INVENTION

The present invention relates generally to wireless communication devices and, more particularly, to a technique for detecting an alternate wireless communication network for the wireless communication device.

BACKGROUND

Wireless communication devices, for example mobile devices, often have the capabilities to operate in different types of geographic and radio access networks. Mobile devices often have a preferred network, service provider, and/or radio access technology (RAT). The preferred choice often depends upon the cost of the service, contractual terms between the user and the service provider, the mobile device's capabilities, the present location of the mobile device, and/or other priority factors.

When a mobile device is switched ON, it starts scanning for available networks. Also, when scanning for a network, the mobile device must determine whether a found network supports the particular radio access technology used by the mobile device. In existing systems, if the acquired network or RAT or service provider is not the first choice, the mobile device often continues to scan, in hopes of finding a higher, more preferred choice. Existing multi-mode mobile devices are battery powered and can consume a great deal of energy searching for alternate networks while still operating in a particular network. Such scanning by the mobile station uses additional energy of the battery of the mobile device and also consumes valuable processing time.

Nowadays, the increasing number of networks having different RATs plus the increasing number of multi-mode mobile devices results in a longer scanning and registration time period. First, the number of available networks of different RATs in a particular geographic area has increased. Second, the number of RATs a single mobile device can access has increased. Thus, the numbers of possible matching combinations have increased (e.g., matching the mobile devices capabilities with the available networks in a particular geographic area). After the matching combinations have been determined, they are ranked based on a variety of preference factors and, finally, the highest priority network is selected for registration.

Even after an initial network is acquired, the mobile device must account for the possibility that it may be on the edge of coverage for one particular network and should therefore be ready for a network handoff. Since initial acquisition on a new network is often a time consuming process, taking many seconds per failed attempt and often multiple seconds for successful attempts, the multi-mode mobile device continuously looks for alternate networks on several different channels and multiple RATs which also consumes a lot of battery power.

Accordingly, there is a need for new scanning methods that can reduce the amount of time and power it takes to acquire an alternate wireless communication network for the mobile device capable of operating in multiple modes.

DETAILED DESCRIPTION

A multi-mode wireless communication device uses a first radio access technology (RAT) when scanning for an initial wireless communication network and registers with the initial wireless communication using the first RAT. The wireless communication device then receives alternate RAT wireless communication network information from the initial wireless communication network using the first RAT. The device may select a network based on the alternate RAT wireless communication network information and scan for that network using the associated alternate radio access technology. By receiving alternate RAT wireless communication network information from the initial wireless communication network rather than during an initial scanning process, the multi-mode wireless communication device can quickly register on an initial wireless communication network and also quickly transfer to a more-preferred alternate wireless communication network.

FIG. 1is a system100diagram with various wireless communication systems and a wireless communication device in accordance with some embodiments. The system100shows various wireless communication systems101,103,105,107, and109using different radio access technologies.

A wireless communication system includes a radio access network (RAN) side coupled to a core network (CN). The RAN side generally has at least a base station controller coupled to base stations, which can be in communication with wireless communication devices. The RAN manages wireless communication links with the wireless communication devices using a particular radio access technology (RAT).

The core network (CN) generally includes a mobile switching network, a packet data network, and other network entities. The CN manages communication links to fixed networks and mobile networks. Examples of fixed networks include a public-switched telephone network, an integrated service digital network, and the Internet. In current wireless communication systems, the RANs and the CNs are configured such that one RAN is usually connected to one CN.

The wireless communication system101has a CN121and the RAN side111. The CN121is a code division multiple access radio access (CDMA) network and the RAT employed in the wireless communication system101is CDMA 1x radio access technology. The arrows coming out and going in the CN121are used to connect the CN121to fixed networks, mobile networks, and other core networks.

Like the CDMA system101, the wireless communication system103also has a CN123and the RAN side113. The system103, however, is universal mobile telecommunication system (UMTS). The CN123of UMTS shares many components with a Global System for Mobile Communication (GSM) core network (see below), and the RAT employed in the wireless communication system103is universal mobile telecommunication system (UMTS) radio access technology, which is usually based on wideband CDMA technology. The arrows coming out and going in the CN123are used to connect the CN123to fixed networks, mobile networks, and other core networks.

The wireless communication system105is a Global System for Mobile communications (GSM) system and has a Global system for mobile communications radio access network (GRAN) on its RAN side115and a GSM core network as its CN125. The arrows coming out and going in the CN125are used to connect the CN125to fixed networks, mobile networks, and other core networks.

The wireless communication system107is a wireless local area system and has an IEEE 802.11 radio access technology on its RAN side117and a WiFi core network as its CN127. The arrows coming out and going in the CN127are used to connect the CN127to fixed networks, for example, Internet137, mobile networks, and other core networks.

The wireless communication system109is a GSM/EDGE system and has a GERAN radio access technology on its RAN side119and a GERAN network as its CN129. The arrows coming out and going in the CN129are used to connect the CN129to fixed networks, mobile networks, and other core networks.

FIG. 1may include additional or alternate existing and/or evolving wireless communication systems. For example,FIG. 1may also (or alternately) include a Land Mobile Radio (LMR) system, which has a Land Mobile radio access technology on its RAN side and a LMR network as its CN. The LMR CN may be connected to fixed networks, mobile networks, and other types of core networks. In another variant,FIG. 1may also include a WiMAX system. The WiMAX system has a multiple-input multiple-output scalable orthogonal frequency-division multiple access (MIMO SOFDMA) radio access technology on its RAN side and a WiMAX network as its CN. The WiMAX CN may also be connected to fixed networks, mobile networks, and other core networks. Also, an LTE (Long Term Evolution) network can be included inFIG. 1.

The system100also shows a multi-mode wireless communication device190, sometimes referred to as user equipment (UE) when addressed in CDMA-based literature and a mobile station (MS) when addressed in GSM-based literature. The multi-mode wireless communication device190is equipped with the transceiver technology for using multiple RATs to interface with multiple wireless communication systems. The wireless communication device190can be representative of multiple wireless communication devices. In the example ofFIG. 1, the multi-mode wireless communication device190is capable of CDMA 1x, GSM/EDGE, and WiFi wireless communication modes and is shown as connected to the CDMA radio access network (RAN111) using CDMA 1x communications195.

The multi-mode wireless communication device190has turned on and initially scanned using CMDA 1x radio access network111technology and registered on this initial network, CN121. By scanning using only a CDMA 1x transceiver, the multi-mode wireless communication device190can quickly register with the system101among all the available systems101,103,105,107,109within the geographic range of the device190. This CDMA system101, however, may not be the most preferred network available. For example, the WiFi system107is in close proximity and may be available at a lower cost. Or the GSM/EDGE system109may be available and be a home network for the device. After the device is registered with an initial network, the initial network sends alternate wireless communication network information to the device so that the device can switch to a more preferred network, if available.

FIG. 2is a sample signal flow diagram200between a multi-mode wireless communication device290and an initial wireless communication network201for a method for selecting an alternate wireless communication system in accordance with some embodiments. The vertical line from the wireless communication device290represents signaling to and from the wireless communication device290. The vertical line from the initial wireless communication network201represents signaling to and from the initial wireless communication network201.

Initially, when the multi-mode wireless communication device290is switched ON, it scans202for an initial wireless communication network using its one or more transceivers. This initial scanning can use less than all of its capabilities in order to reduce the amount of time needed to find a suitable network. For example, the device290has CDMA, GSM/EDGE, and WiFi transceiver technology. During initial scanning, however, it uses only the RAT last used by the device—which is CDMA in this situation. When the device290finds the initial wireless communication network using the first RAT, the device290registers215to the initial wireless communication network201, even though that network may be weak or may not be a preferred system.

After registering, the device290may send a request225for alternate RAT wireless communication network information to the initial wireless communication network201. The request may include radio access capabilities of the multi-mode device, the preference level of the initial network (e.g., roam, preferred, home, etc.), the approximate location of the device (as determined at the device), and other network preference and priority factors. In lieu of an explicit request signal225, the initial registration215may automatically trigger a request for alternate RAT wireless communication network information within the initial wireless communication network201. If the initial network is aware of information specific to the device (e.g., the radio access capabilities, the preference level of the network at the device, the location of the device, etc.) it can be included in the automatic request.

The alternate RAT wireless communication network information requested may provide a list of alternate wireless communication networks and different RATs for the multi-mode wireless communication device. This information may be in the form of a frequency band, a channel set, a channel assignment, a channel allocation, signaling codes, security codes, system identifiers, system timing of alternate RATs relative to the first RAT, or a timing error of alternate RATs.

After receiving an explicit or implicit request that does not include the approximate geographic location of the device, the initial wireless communication network201may find204the present location of the device using location techniques known in the art.

Subsequently, the initial wireless communication network201determines206alternate RAT wireless communication network information for the device290. This alternate RAT wireless communication network information determined by the initial network201may be selected depending on one or more of the following factors, which may be provided by the device or determined by the initial network: the priority factors for network selection at the device, the present location of the device, the requested or anticipated services, non-RAT capabilities of the device, signal strength, RAT capabilities of the device, lowest transmit power, or any other factor that can be used by the initial wireless communication network to determine alternate RAT wireless communication network information for the device. Priorities may also be affected by lowest cost, lowest cost per bit (data), highest data rate, etc.

After determining the appropriate information to include, the initial wireless communication network sends235the alternate RAT wireless communication network information to the device290. In one example, the initial wireless communication network may send the alternate RAT information to multiple wireless communication devices either through individual addressing, group addressing, or a broadcast.

If the alternate RAT wireless communication network information includes a list of alternate networks and different RATs, the device290selects240a first alternate wireless communication network from within the received alternate RAT wireless communication network information based on prioritization factors known by the device290. After selecting the first alternate wireless communication network, the device290scans for the first alternate wireless communication network using the alternate RAT associated with the first alternate wireless communication network. As a result of scanning, if the device290finds the first alternate wireless communication network, the device290registers to the first alternate wireless communication network. If the scanning is unsuccessful, which would be unusual if the device is stationary, then the next-highest priority alternate wireless communication network and associated RAT is selected for scanning. If the alternate RAT wireless communication network information represents only one alternate network and corresponding RAT, the device290may scan for it and register to it without any need for selection among options within the list.

FIG. 3is a flowchart of a method for a wireless communication device to select an alternate wireless communication system in accordance with some embodiments. We shall use as an example the multi-mode wireless communication device190inFIG. 1, which has just been switched ON and registered with the CDMA system101. In this example, the device190was connected to a CDMA network (not necessarily CDMA system101) before it was switched OFF. In this embodiment, the device190will scan using its CDMA transceiver when next turned ON, because this embodiment uses the most recently-used RAT for initial scanning to save time and energy. Alternate turn-on transceivers may be selected based on a preferred radio access technology or for other reasons.

After the device190is turned ON, the method300starts in step305when the device190scans for an initial wireless communication network using a transceiver using the first RAT (CDMA 1x). As a result, the device190finds the initial wireless communication system101and in step310the device190registers with the initial wireless communication system101, even though that network may have a weak signal or have a low priority (e.g., “roam” or “preferred” instead of “home”).

In one embodiment, the registration process of the wireless communication device190with the initial wireless communication network includes an automatic (or implicit) request for alternate RAT wireless communication network information from the initial wireless communication network. In another embodiment, after registering, the device190transmits an explicit request for alternate RAT wireless communication network information to the initial wireless communication system101in step320. Along with the explicit request, the device190may also transmit one or more priority factors. Instead of (or in addition to) transmitting priority factors, while registering, the device190may transmit its unique identity to the initial wireless communication system101, and this unique identity may be associated with priority factors stored at the initial wireless communication system101. Along with the explicit request, the device190may also transmit its present location to the initial wireless communication system101. In one example, the requesting may be performed by using short messaging service (SMS).

In step330, the device190receives a message with alternate RAT wireless communication network information. The alternate RAT wireless communication network information can be based at least on a priority factor, or on a present location of the device190, or both. The alternate RAT wireless communication network information includes a list of alternate wireless communication networks and different RATs (CDMA, GSM, EDGE, WiFi, LMR, etc.), for the multi-mode wireless communication device. This information may be in the form of a frequency band, a channel set, a channel assignment, a channel allocation, signaling codes, security codes, system identifiers, system timing of alternate RATs relative to the initial RAT, or a timing error of alternate RATs.

If the first RAT is one of GRAN, GERAN, CDMA 1x, UTRAN, or any other wireless RAT, then receiving the alternate RAT wireless communication network information may use packet data signaling or a short messaging service (SMS). In another example, if the initial RAT is UTRAN then receiving the alternate RAT wireless communication network information may use a multimedia broadcast multicast service (MBMS). If the initial RAT is CDMA 1x then receiving the alternate RAT wireless communication network information may use broadcast/multicast service (BCMCS). In yet another example, if the initial RAT is 802.11 (WiFi) then receiving the alternate RAT wireless communication network information may use service set identifier (SSID). If the initial RAT is LMR then receiving the alternate RAT wireless communication network information may use outbound signaling words (OSW) over a control channel or traffic channel. If the initial RAT is a packet data network then receiving the alternate RAT wireless communication network information may use data packets. In the example ofFIG. 1, receiving the alternate RAT wireless communication network information uses BCMCS because the first RAT is CDMA 1x.

The alternate RAT wireless communication network information may have only one best alternate wireless communication network based on the priority factor and/or present location of the wireless communication device as known by the initial wireless communication network. In this case, the selection is easy and the device190select the best alternate wireless communication network provided in the alternate RAT wireless communication network information. In another example, the alternate RAT wireless communication network information has no alternate wireless communication network, if there is no alternate wireless communication network of a higher priority than the initial wireless communication network based on the priority factor and/or present location of the device as known by the initial wireless communication network. In yet another example, the alternate RAT wireless communication network information comprises a list of multiple alternate wireless communication networks based on the priority factor and/or present location of the device as known by the initial wireless communication network.

If the alternate RAT wireless communication network information includes a list of multiple alternate wireless communication networks, then the device190selects a first alternate wireless communication network from within the received alternate RAT wireless communication network information in step340based on its priority factors. (These priority factors may or may not have been transmitted to the initial wireless communication network.)

After selecting a first alternate wireless communication network to try, the device190scans for the first alternate wireless communication network using the alternate RAT in step350. As a result of scanning, if the device190finds the first alternate wireless communication network, the device190registers to the first alternate wireless communication network in step360. Otherwise, the device190keeps on repeating the selection and scanning process. That is, the device190selects a second alternate wireless communication network from within the received alternate RAT wireless communication network information, scans for the second alternate wireless communication network using the associated alternate RAT, and registers to it if successful. In a case when the alternate RAT wireless communication network information includes a channel assignment, then the device190skips step350. In this scenario, the device190does not scan for the first alternate wireless communication network, but directly registers to it, using the channel assignment information provide in the alternate RAT wireless communication network information.

In the example ofFIG. 1, for instance, the device190registers to CN121and transmits a request for alternate RAT wireless communication network information. Along with the request, the device190also transmits its present location as well as a priority factor. In this example, the priority factor is the RAT capabilities of the device190, and it specifies that the device190is capable of handling GRAN, GERAN, and WiFi radio access technologies as well as CDMA 1x. In response to the request, the device190receives alternate RAT wireless communication network information. In this example, the alternate RAT wireless communication network information includes frequency channels (and other information like a channel set, a channel assignment, a channel allocation, signaling codes, security codes, system identifiers, system timing of alternate RATs relative to the initial RAT, or a timing error of alternate RATs) for GRAN115, GERAN119, and WiFi117systems. The device190selects the first alternate wireless communication network CN129from within the received alternate RAT wireless communication network information based on another priority factor (e.g., that its most-preferred “home” network is a GERAN network) and scans for system109using its GERAN transceiver (and the other information provided such as frequency and maybe some codes or a channel set, a channel assignment, a channel allocation, signaling codes, security codes, system identifiers, system timing of alternate RATs relative to the initial RAT, a timing error of alternate RATs, etc.). Assuming the device190finds the system109, the device190registers to it.

By scanning using only a subset of transceivers available to a multi-mode device, it can quickly find and register on an initial network. This network may not be the most ideal for communication with the device, but the device can receive alternate information from the initial network. Based on priority factors known to the initial network or the device, the device can select a first alternate network with a higher priority than the initial network. By scanning using the alternate network information and registering on an alternate network, the device may save battery power, reduce processing time, and improve user experience compared with scanning all available networks using all available transceivers.

In an example where the aforementioned method can be used, a mobile station can quickly find and register to a wide area network (for example, GSM, UMTS), rather than local area or metropolitan area network (for example, WiFi, WiMAX, LTE). This wide area network may not be the most ideal network for the communication device, but is more easily reached due to its larger footprint. Then the wide area network can provide information about local area or metropolitan area networks that are more appropriate for the communication device but were not easily reachable due to their smaller footprints. Then, the mobile station can switch to a local area or metropolitan area network without having to scan for it separately. This particular implementation may be very useful for network operators that have both wide area networks and local area or metropolitan area networks, because the network operator can use this technique to more easily load-balance among different types of networks.

FIG. 4is a flowchart of a method for a wireless communication network to assist a wireless communication device in selecting an alternate wireless communication system in accordance with some embodiments. This flowchart is a counterpart to theFIG. 3flowchart. The flowchart ofFIG. 3is from the device's point of view while the flowchart ofFIG. 4is from the initial wireless communication network's point of view.

The method400starts with the step405when the initial wireless communication network performs the registration of the device using the first RAT. In one embodiment, the registration process of the wireless communication device190with the initial wireless communication network includes an automatic (or implicit) request to the initial wireless communication network for alternate RAT wireless communication network information. In another embodiment, the initial wireless communication network may receive an explicit request for alternate RAT wireless communication network information in step410. Along with the explicit or implicit request, the initial wireless communication network may receive the device's present location or may find the device's present location in step420. The initial wireless communication network may also receive one or more priority factors in step425, along with the request or by looking up priority factors associated with the device when it registers.

In step430, the initial wireless communication network determines the alternate wireless communication networks with associated RATs for the wireless communication device. These alternate wireless communication networks with associated RATs are included in the alternate RAT wireless communication network information. This information may include a frequency band, a channel set, a channel assignment, a channel allocation, signaling codes, security codes, system identifiers, system timing of alternate RATs relative to the initial RAT, or a timing error of alternate RATs etc. This alternate RAT wireless communication network information can be based on the priority factor, the present location of the device, or both (and other factors mentioned earlier such as device capabilities, home-preferred-roam, etc.). After determining the context of the list, the initial wireless communication network sends a message to the wireless communication device providing alternate RAT wireless communication network information using the first RAT in step440.

Thus, the network provides information to the device so that the device does not have to scan for those alternate RATs. If there are no alternate RATs, the list can be empty. If there is only one alternate RAT that is acceptable according to the priority information known to the network, then the list will only include one alternate RAT's information. If there are multiple alternate RATs that may be acceptable to the device, then the list may include a number of alternate RATs and let the device select a first alternate RAT to scan first.

FIG. 5is a block diagram500of a multi-mode wireless communication device590connected to an initial wireless communication network560in accordance with some embodiments. The block diagram500includes a wireless communication device590, sometimes referred to as user equipment (UE) in CDMA literature and a mobile station (MS) in GSM literature. The device590is in communication with an initial wireless communication network560using a first radio access technology595. The device590has a processor510, memory515, controller520, transceivers525, a GPS (Global Positioning System) receiver530, and an antenna538.

The antenna538is responsible for the transmission and reception of signals to and from the device590. The antenna is connected to the transceiver525. The transceiver525is used for transmitting and receiving signals to and from the antenna538. Because the device is a multi-mode device, the transceiver525is a composite transceiver capable of operating using one of several different RATs. The transceiver525has a first RAT transceiver521that operates using CDMA 1x protocols, a second RAT transceiver522that operates using GSM/EDGE protocols, and a third RAT transceiver523that operates using WiFi protocols. The second RAT transceiver522and the third RAT transceiver523are considered alternate RAT transceivers at this time, because the CDMA 1x transceiver521is currently in operation. There can be more alternate RAT transceiver depending upon the RAT capabilities of the device. The alternate RAT transceiver may change depending on the priority in the device. WhileFIG. 5shows a single antenna for all the individual transceivers, it is possible to replace the single antenna with a separate antenna for each transceiver, or for two or more transceivers to share an antenna.

In accordance with the examples used previously, a device turns ON and scans using the transceiver used prior to the device being turned OFF. If the previously-used transceiver was a CDMA transceiver, the device scans for CDMA networks and registers on a best-available CDMA network560without regard for other networks available that use different RATs. (SeeFIG. 1) After the device is registered on the CDMA network560, it transmits a request to the initial wireless communication network560for alternate RAT wireless communication network information using the first RAT (CDMA 1x). The first RAT transceiver521receives a message containing the alternate RAT wireless communication network information using the first RAT (CDMA 1x). The device selects a network from the information and an alternate RAT transceiver522or523scans for the alternate wireless communication network using the alternate RAT. The selection of the alternate transceiver to be used depends on the alternate RAT that is selected. In this example, if the alternate RAT is IEEE 802.11, then the third RAT transceiver523is used. And if the alternate RAT is GERAN, then the second RAT transceiver522is used.

The transceiver525is coupled to the GPS receiver530. The GPS receiver530is also coupled to the processor510and the controller520. The GPS receiver530is used by the device590to determine its own present location. Although a GPS receiver is used here as an example, other positioning or location technologies can be substituted. This present location is sent to the initial wireless communication network560with the request for alternate RAT wireless communication network information, in this embodiment.

The transceiver525is also coupled to the controller520. The controller is coupled to the memory515that stores the priority factors. The memory515and the controller520are coupled to the processor510. The processor510includes a first processor sub-unit504and a second processor sub-unit508. The first processor sub-unit504selects an alternate RAT wireless communication network based on the priority factor(s) stored in the memory515. The second processor sub-unit extracts the alternate RAT wireless communication network information from the message received by the first RAT transceiver521. Depending on the technology of the first RAT, the message may be a short messaging service (SMS) message, a multimedia broadcast multicast service (MBMS) message, a broadcast/multicast service (BCMCS) message, a service set identifier (SSID) message, outbound signaling words, data packets, or the like.

The initial wireless communication network560includes a processor545, a database540, an alternate RAT selector550, a controller555, a transceiver565, and an antenna568. The processor545is coupled to the database540. The database540has a first database544for storing information about other wireless communication networks in the vicinity and a second database548that is optional. The second database548stores priority factors, if any, for one or more wireless communication devices. In this example, the second database stores RAT capabilities of the wireless communication devices. The database540is coupled to the alternate RAT selector550, which is also coupled to the processor545as well as the controller555. The alternate RAT selector550selects the alternate RAT wireless communication network information from the first database544to send to the device590.

In one example, the alternate RAT selector550may select the alternate RAT wireless communication network information based on a present location of the device590. The present location of the device590can either be transmitted by the device590(determined using a GPS receiver530, for example) to the initial wireless communication network560or it can be found by the initial wireless communication network560using known techniques. In another example, the alternate RAT selector550may select the alternate RAT wireless communication network information based on RAT capabilities of the device590stored in the second database548. In yet another example, the alternate RAT selector550may select the alternate RAT wireless communication network information based on another priority factor transmitted by the device590to the initial wireless communication network560such as a list of preferred networks. The alternate RAT selector550may also select the alternate RAT wireless communication network information based multiple priority factors, such as the device's transceivers plus the present location of the device590.

The alternate RAT selector550sends the alternate RAT wireless communication network information to the transceiver565to transmit to the device590. The transceiver includes a receiver562and a transmitter564. The transmitter564uses the first RAT to transmit the alternate RAT wireless communication network information to the device590. The receiver562uses the first RAT to receive all the messages, requests, etc. from device590. The transceiver565is coupled to the antenna568that is responsible for reception and transmission of signals.

We shall use, as an example, the device190inFIG. 1as an instance of the device590inFIG. 5, which has just been switched ON. For instance, the device190was connected to the CDMA radio access network111before it was switched OFF. This information is stored in the device190. Then, in this embodiment, CDMA 1x radio access technology is the first RAT for the device190and will be activated upon turn ON of the device. After the device590is turned ON, the device590uses the first RAT (CDMA) transceiver521to scan for a CDMA system101using its first RAT (CDMA 1x). As a result, the device590finds RAN111and registers with the initial wireless communication system101regardless of signal strength or network priority. The device590uses the first RAT transceiver521to transmit a request for alternate RAT wireless communication network information, after registering to CDMA system101. Along with the request, in this embodiment, the device590also transmits its present location as determined using its GPS receiver530.

The initial wireless communication network560(CDMA system101) receives the request via its receiver562. In response to the request, the initial wireless communication network560uses the alternate RAT selector550to select appropriate alternate RAT wireless communication network information from the first database544to send to the device590. The alternate RAT selector550selects the appropriate alternate RAT wireless communication network information based on the RAT capabilities of the device590and the location reported by the device590. The RAT capabilities of the device590are retrieved from the second database548by using the unique identifier transmitted by the device590to the network560during registration. In this example, the RAT capabilities of the device590are GRAN, GERAN, and WiFi. The transmitter564transmits the selected alternate RAT wireless communication network information to the device590using the first RAT (CDMA 1x) in a BCMCS message in this example.

In this example, the alternate RAT selector550with the help of the processor545and the controller555selects the alternate RAT wireless communication network information based on a present location of the device590sent by the device590in the request as well as the RAT capabilities of the device590. The alternate RAT wireless communication network information may also be based on another priority factor transmitted by the device590to the initial wireless communication network560such as a list of preferred networks. The alternate RAT selector550may also select the alternate RAT wireless communication network information based on any number of combinations of priority factors known to the alternate RAT selector550.

The device590receives alternate RAT wireless communication network information via the first RAT transceiver521. In this example, the alternate RAT wireless communication network information includes GERAN RAT information for GERAN system109and WiFi RAT information for WiFi system107. The device590uses the second processor sub-unit to extract the alternate RAT wireless communication network information from the BCMCS message received by the first RAT transceiver521. The device590selects the first alternate RAN from within the received alternate RAT wireless communication network information and uses the alternate RAT transceiver that can be the second RAT transceiver522or the third RAT transceiver523for scanning the frequency indicated in the information. Selecting the second RAT transceiver522or the third RAT transceiver523for scanning the frequency indicated in the information depends upon the alternate RAT used. In this example, the second RAT transceiver522operates using GSM/EDGE protocols, and the third RAT transceiver523operates using WiFi protocols. If the alternate RAT selected for scanning is IEEE 802.11, then the third RAT transceiver523is used and if the alternate RAT selected for scanning is GERAN, then the second RAT transceiver522is used. As a result of scanning the device190finds an alternate RAN, and registers to its associated network.

The initial wireless communication network provides information to the device so that the device does not have to scan for alternate RATs. If there are no alternate RATs, the list can be empty. If there is only one alternate RAT that is acceptable according to the priority information known to the network, then the list will only include one alternate RAT's information. If there are multiple alternate RATs that will be acceptable to the device, then the list may include a number of alternate RATs and let the device select a first alternate RAT to scan first. Thus, the aforementioned method will reduce the amount of time and power it takes to scan and acquire an alternate wireless communication network for the wireless communication device.