Abstract:
An exemplary method for selecting one of a plurality of systems on a multi-mode device capable of communicating on a first air interface technology and a second air interface technology is disclosed. Initially, a carrier input associated with one of the first and second air interface technologies is received. The carrier input typically defines at least one system selection event. Next, a first network acquisition attempt of the other one of the first and second air interface technologies is triggered responsive to the system selection event. The results of the first network acquisition attempt are determined and stored, and subsequently used for subsequent system selection determinations between the first and second air interface technologies.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application 60/786,759, filed Mar. 27, 2006, which is hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to the field of wireless communication devices. More specifically, the invention relates to a system selection technique for wireless communication devices capable of a communication over a plurality of air interface technologies. 
       BACKGROUND OF THE INVENTION 
       [0003]    A typical wireless communication device, such as a mobile phone, comprises, among other things, a processor coupled to a memory and to a transceiver, each enclosed in a housing. A mobile power source, such as a battery, is coupled to and supplies power to the processor, the memory and the transceiver. A speaker and a microphone are also enclosed within the housing for transmitting and receiving, respectively, acoustic signals to and from a user of the wireless communication device. The wireless communication device communicates information by transmitting and receiving electromagnetic (“EM”) energy in the radio frequency (“RF”) band via an antenna coupled to the transceiver. 
         [0004]    More recently, mobile communication devices have been developed that communicate over a plurality of air interface technologies. For example, a mobile handset may be designed to incorporate both cellular telephony technology and wireless local area network (“WLAN”) technology. Such devices can be referred to as multi-mode handset devices, because of the multiple air interface modes in which the device may be configured. 
         [0005]    A significant challenge facing the design and development of multi-mode handsets is the ability to efficiently and optimally configure the device to an appropriate air interface. For example, if the handset were configured such that cellular networks have priority over WLAN, it would be very difficult for multi-mode handset to access WLAN. The main reason for this difficulty is the fact that WLAN coverage is small and spotty compared to cellular network coverage, and further because WLAN Access Points (“APs”) are typically embedded within cellular network coverage. 
         [0006]    Accordingly, there is a strong need in the art for an efficient and optimized method for providing system selection for multi-mode wireless communication devices. 
       SUMMARY OF THE INVENTION 
       [0007]    An exemplary method for selecting one of a plurality of systems on a multi-mode device capable of communicating on a first air interface technology and a second air interface technology is disclosed. Initially, a carrier input associated with one or more of the first and second air interface technologies is received. The carrier input typically defines at least one system selection event. Next, a first network acquisition attempt of the other one of the first and second air interface technologies is triggered responsive to the system selection event. The results of the first network acquisition attempt are determined and stored. In this way, a subsequent system acquisition selections between the first and second air interface technologies can be based upon the stored results of the first network acquisition attempt, resulting in significantly improved and efficient system selection determinations. 
         [0008]    Other features and advantages of the present invention will become more readily apparent to those of ordinary skill in the art after reviewing the following detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  illustrates a network arrangement including an exemplary multi-mode wireless communication device according to one embodiment of the present invention. 
           [0010]      FIG. 2  illustrates an exemplary flowchart for providing multi-mode system selection of a multi-mode device according to one embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    Referring first to  FIG. 1 , there is shown network arrangement  100  including exemplary multi-mode wireless communication device  110  according to one embodiment of the present invention. By way of example, multi-mode device  110  may be a mobile phone capable of communicating over two or more radio access technologies. According to one particular embodiment, multi-mode device  110  is capable of communicating over one of the several cellular networks  112  in accordance with code division multiple access (CDMA 2000, IS-95), Global System for Mobile Communications (GSM), WCDMA, or other Wireless Wide Area Networks (WWAN) standard, for example, and is further capable of communicating over one of the several packet data networks  114  in accordance with IEEE 802.16, IEEE 802.20, or other Wireless Local Area Networks (WLAN) protocols, such as IEEE 802.11, Bluetooth, for example. 
         [0012]    As shown in  FIG. 1 , multi-mode device  110  comprises processor  116  coupled to a memory  118  and to first transceiver  120  and second transceiver  122 . Programming is stored in memory  118  and executed by processor  116  for the operation of multi-mode device  110 . The details of the operation of multi-mode device  110  are described more fully below in conjunction with  FIG. 2 . First transceiver  120  is coupled to antenna  124  for communication with network  112 , and second transceiver  122  is coupled to antenna  16  for communication with network  114 . Processor  116  is also coupled to interface  128 , which may further be coupled to one or more user-interface (UI) devices (not shown), such as a display device, input keys, a microphone, and a speaker, for example. 
         [0013]    Referring now to  FIG. 2 , there is shown exemplary flowchart  200  for providing multi-mode system selection for a multi-mode device according to one embodiment of the invention. The multi-mode system selection technique depicted in  FIG. 2  may be implemented in multi-mode device  110  of  FIG. 1 . 
         [0014]    In flowchart  200 , a plurality of inputs or parameters ( 224  and  226 ) are provided to overlay function  216 . Overlay function  216  is executed by processor  116  of multi-mode device  110  in order to determine the operation of multi-mode device  110 . Specifically, overlay function  216  determines which air-interface technology multi-mode device  110  will operate. Once a particular air interface technology is selected for operation, multi-mode device  110  will operate according to the appropriate technology standard for that air-interface technology. In some cases, overlay function may further determine that multi-mode device  110  may operate simultaneously according to more than one air-interface technology, as discussed below 
         [0015]    Referring again to  FIG. 2 , method  200  begins with providing carrier inputs  224  and overlay function inputs  226  to overlay function algorithm  254  of overlay function  216 . Carrier inputs  224  may be provided by a network carrier (e.g., the cellular network carrier) for one of the wireless interface technologies that multi-mode device  110  operates. Carrier inputs  224  may be provided at the time multi-mode device  224  is provisioned, e.g., during initial device set up for the end user. In some cases, carrier inputs  224  may be provided periodically during updates to multi-mode device  110 , e.g., via over-the-air update. 
         [0016]    Carrier inputs  224  may include conditions, events or limitations for determining when the overlay function algorithm  254  should be executed by multi-mode device  110 . Examples of conditions or limitations that may be used as inputs to overlay function  216  include: enable or disable status for WLAN services, period for executing overlay function, manual override and manual initiation, at a beginning of an application, in response to certain user interface input, system loss for a certain period of time, at device power-up, or change in location of the device, or upon a network triggering event (e.g. WLAN advertisement). Carrier inputs  224  are generally included as part of overlay function input parameters  226  provided to overlay function algorithm  254 . 
         [0017]    As shown in  FIG. 2 , exemplary overlay function input parameters  226  may include application type  230 , location  232 , manual override  234 , qualify of service (“QoS”)  236 , passive search  238 , and acquisition history  240 , for example. In certain embodiments, each of input parameters ( 230 - 240 ) may have a static component ( 242 A- 252 A) and/or a dynamic component ( 242 B- 252 B). Static components may be pre-programmed and may not change often. Dynamic components often change frequently and may be updated in order for overlay function  216  to operate efficiently. 
         [0018]    By way of illustration, static components  242 A may define which air interface is suitable for a particular user application, dynamic component  242 B may define which application is currently being used, static components  244 A may define the range between the device&#39;s location and the WLAN location where there is an certain percentage of probability for the device to acquire WLAN, dynamic component  244 B may define the device&#39;s current location and the WLAN locations, static component  248 A may define latency or data rate, and dynamic parameter  252 B may define history of recent network acquisition and reason for failure in an acquisition, for example. 
         [0019]    At block  254  overlay function algorithm is executed based upon static and dynamic inputs  242 A- 252 A,  242 B- 252 B. The particular algorithm for system selection typically depends upon the particular air interface technologies, the carrier requirements, and the parameters provided by static and dynamic inputs  242 A- 252 A,  242 B- 252 B. By way of illustration, if a Video Streaming or Web-Browsing application is selected by the user of multi-mode device  110  (dynamic parameter  242 B), and if a WLAN location directory is available to multi-mode device  110  (static parameter  244 A), overlay function  216  may use the user&#39;s application selection and the WLAN location directory information to determine (at decision block  256 ) that multi-mode device  110  should operate as a WLAN radio (block  222 ) and attempt to acquire a WLAN access point (generally represented by block  257 ). Conversely, unnecessary search attempts (block  258 ) for WLAN access points can be avoided if, as a result of static and dynamic inputs  242 A- 252 A,  242 B- 252 B, overlay function  216  determines (at decision block  256 ) that multi-mode device  110  should operate as a cellular radio (block  220 ). 
         [0020]    If overlay function  216  determines that multi-mode device  110  should operate as a WLAN radio, a determination is made if WLAN service is already enabled (associated, authenticated, authorized), e.g., from a previous WLAN session (at block  258 ). If WLAN service is already enabled, method  200  continues to block  270  as discussed below; otherwise, multi-mode device  110  attempt to acquire WLAN Service at block  262 . Multi-mode device  110  may request or access WLAN acquisition parameters from the cellular network prior to switching to WLAN operation; alternatively, multi-mode device  110  may use existing WLAN information stored in the device (block  260 ). By way of illustration, WLAN acquisition parameters may include Service Set Identifiers (“SSIDs”) with geographical information (“GEO”) association tags. Other WLAN network parameters, such as authentication and authorization parameters, may also be available to multi-mode device  110  once the device acquires a WLAN AP, and assist with the typical functions of the WLAN radio. 
         [0021]    Once multi-mode  110  acquires a WLAN AP, the device would typically authenticate with the WLAN AP (block  262 ) followed by an authorization with the upper layer in the core network as needed. If full service acquisition is unsuccessful (determined at block  264 ), further attempts to associate, authenticate and gain authorization from the next WLAN AP network (block  268 ) is carried out until the last WLAN AP network (determine at block  266 ) is attempted. If a WLAN AP network was not successfully acquired and the WLAN AP networks have been exhausted (at block  266 ), the results of the WLAN network acquisition attempt and failure are recorded and reported (at block  276 ) as acquisition history inputs  240  and dynamic input parameters  252 B to overlay function  216  as shown by path  278 . For example, the results recorded and reported may include the success and/or failure of each attempt at association, authentication, and authorization for a particular WLAN network. 
         [0022]    If full service acquisition is successful (at block  264 ), multi-mode device  110  would be considered to have reached idle state or equivalent in that system. Additionally, the device may also attempt to register with the home cellular network so that incoming pages can be received by the device on WLAN. If this cellular registration is also successful, the device may operate in WLAN only (single radio mode—block  272 ) without missing any incoming pages from the cellular network. If the registration with the home cellular network fails, the device may choose to: (1) stay on WLAN and simultaneously monitor the cellular network (for devices capable of simultaneous operation—determined at blocks  270  and  274 ), (2) stay on WLAN and periodically monitor the cellular network (hybrid mode—block  272 ), or (3) choose to stay in WLAN with incoming pages sent to voicemail (single radio mode—block  272 ). Alternatively (not shown), the device may re-acquire the cellular network and stop operation on WLAN (i.e. redirection). As shown in  FIG. 2 , the results of the home cellular network registration attempt and success/failure, and/or the operating mode of multi-mode device  110  as a result of the home cellular network registration attempt and success/failure are recorded and reported (at block  276 ) as acquisition history inputs  240  and dynamic input parameters  252 B to overlay function  216  as shown by path  278 . The results recorded and reported may include the indication of loss of service and the metrics associated with the loss of service. 
         [0023]    In some embodiments, the acquisition history inputs  240  are also reported to the network provider of the cellular network via cellular radio  220 . In response to the reported results, the network provider may update the carrier inputs  224  provided to overlay function  216  to further improve efficiency of system selection. For example, such updates can include updated parameters for use with association, authentication, and/or authorization steps (block  262 ), as discussed above. 
         [0024]    From the above description of exemplary embodiments of the invention, it is manifest that various techniques can be used for implementing the concepts of the present invention without departing from its scope. Moreover, while the invention has been described with specific reference to certain embodiments, a person of ordinary skill in the art would recognize that changes could be made in form and detail without departing from the spirit and the scope of the invention. The described exemplary embodiments are to be considered in all respects as illustrative and not restrictive. It should also be understood that the invention is not limited to the particular exemplary embodiments described herein, but is capable of many rearrangements, modifications, and substitutions without departing from the scope of the invention.