Abstract:
A method of integrating a licensed wireless system and an unlicensed wireless system includes initiating a wireless communication session in a first region serviced by a first wireless system and maintaining the wireless communication session in a second region serviced by a second wireless system. The first wireless system is selected from the group including a licensed wireless system and an unlicensed wireless system. The second wireless system is the unselected system from the group including the licensed wireless system and the unlicensed wireless system.

Description:
[0001]    This application claims priority to the following provisional patent applications Nos.: 60/271,766; 60/271,767; 60/271,768; and 60/271,769, each of which was filed on Feb. 26, 2001. 
     
    
     
       BRIEF DESCRIPTION OF THE INVENTION  
         [0002]    This invention relates generally to telecommunications. More particularly, this invention relates to a technique for seamlessly integrating voice and data telecommunication services across a licensed wireless system and an unlicensed wireless system.  
         BACKGROUND OF THE INVENTION  
         [0003]    Licensed wireless systems provide mobile wireless communications to individuals using wireless transceivers. Licensed wireless systems refer to public cellular telephone systems and/or Personal Communication Services (PCS) telephone systems. Wireless transceivers include cellular telephones, PCS telephones, wireless-enabled personal digital assistants, wireless modems, and the like.  
           [0004]    Licensed wireless systems utilize wireless signal frequencies that are licensed from governments. Large fees are paid for access to these frequencies. Expensive base station equipment is used to support communications on licensed frequencies. Base stations are typically installed approximately a mile apart from one another. As a result, the quality of service (voice quality and speed of data transfer) in wireless systems is considerably inferior to the quality of service afforded by landline (wired) connections. Thus, the user of a licensed wireless system pays relatively high fees for relatively low quality service.  
           [0005]    Landline (wired) connections are extensively deployed and generally perform at a lower cost with higher quality voice and higher speed data services. The problem with landline connections is that they constrain the mobility of a user. Traditionally, a physical connection to the landline was required. Currently, unlicensed wireless communication systems are deployed to increase the mobility of an individual using a landline. The mobility range associated with such systems is typically on the order of 100 meters. A common unlicensed wireless communication system includes a base station with a physical connection to a landline. The base station has a RF transceiver to facilitate communication with a wireless handset that is operative within a modest distance of the base station. Thus, this option provides higher quality services at a lower cost, but the services only extend a modest distance from the base station.  
           [0006]    Thus, there are significant shortcomings associated with current landline systems and licensed wireless systems. For this reason, individuals commonly have one telephone number for landline communications and one telephone number for licensed wireless communications. This leads to additional expense and inconvenience for an individual. It would be highly desirable if an individual could utilize a single telephone number for both landline communications and licensed wireless communications. Ideally, such a system would allow an individual, through seamless handoffs between the two systems, to exploit the benefits of each system.  
         SUMMARY OF THE INVENTION  
         [0007]    A method of integrating a licensed wireless system and an unlicensed wireless system includes initiating a wireless communication session in a first region serviced by a first wireless system and maintaining the wireless communication session in a second region serviced by a second wireless system. The first wireless system is selected from the group including a licensed wireless system and an unlicensed wireless system. The second wireless system is the unselected system from the group including the licensed wireless system and the unlicensed wireless system.  
           [0008]    Advantageously, services that would typically be provided via a licensed wireless system can be delivered to the unlicensed base station using inexpensive and high quality landline networks. The unlicensed base station subsequently provides service to a handset using unlicensed, free spectrum (e.g., spectrum around 2.4 GHz or 5 GHz). Thus, when a subscriber is within range of the unlicensed base station, the subscriber enjoys low cost, high speed, and high quality voice and data services. In addition, the subscriber enjoys extended service range since the handset can receive services deep within a building. This type of service range is not reliably provided by a licensed wireless system.  
           [0009]    The invention also allows the subscriber to roam outside the range of the unlicensed base station without dropping communications. Instead, roaming outside the range of the unlicensed base station results in a seamless handoff (also referred to as a hand over) wherein communication services are automatically provided by the licensed wireless system.  
           [0010]    While the invention provides advantages to the subscriber, the invention also provides advantages to the wireless system service provider. First, the unlicensed base stations are relatively low cost and therefore the wireless system service provider is in a position to extend services without incurring significant infrastructure expense. Further, the integration of the landline and wireless systems allows a single communication service provider to secure fee-paying accounts for both landline and wireless services. Finally, since the invention relies upon installed wireless system infrastructure for services such as authentication, expensive system upgrades are not required. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0011]    The invention is more fully appreciated in connection with the following detailed description taken in conjunction with the accompanying drawings, in which:  
         [0012]    [0012]FIG. 1 illustrates an apparatus for integrating a licensed wireless system and an unlicensed wireless system in accordance with an embodiment of the invention.  
         [0013]    [0013]FIG. 2 illustrates a subscriber device configured in accordance with an embodiment of the invention.  
         [0014]    [0014]FIG. 3 illustrates a base station configured in accordance with an embodiment of the invention.  
         [0015]    FIGS.  4 A- 4 D illustrate various base station configurations utilized in accordance with embodiments of the invention.  
         [0016]    [0016]FIG. 5 illustrates a system server for integrating unlicensed and licensed wireless communication systems in accordance with an embodiment of the invention.  
         [0017]    [0017]FIG. 6 illustrates a base station service region and associated transition points between licensed and unlicensed wireless communication services.  
         [0018]    [0018]FIG. 7 illustrates a transition between an unlicensed wireless service and a licensed wireless service in accordance with an embodiment of the invention.  
         [0019]    [0019]FIG. 8 illustrates transitions between unlicensed wireless base stations in accordance with an embodiment of the invention.  
         [0020]    [0020]FIG. 9 illustrates the forwarding of a licensed wireless call to a base station in accordance with an embodiment of the invention.  
         [0021]    [0021]FIG. 10 illustrates a prior art licensed wireless authentication procedure.  
         [0022]    [0022]FIG. 11 illustrates an unlicensed wireless authentication procedure utilized in accordance with an embodiment of the invention.  
         [0023]    [0023]FIG. 12 illustrates system components utilized in a provisioning operation associated with an embodiment of the invention.  
         [0024]    [0024]FIG. 13 illustrates provisioning operations performed in accordance with an embodiment of the invention. 
     
    
       [0025]    Like reference numerals refer to corresponding parts throughout the several views of the drawings.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0026]    [0026]FIG. 1 illustrates a system  10  that may be operated in accordance with an embodiment of the present invention. The system  10  includes a subscriber device  12 , which is a wireless transceiver, such as a cellular telephone, a PCS telephone, a wireless data modem, a wireless enabled Personal Digital Assistant, a wireless enabled computer, and the like. This subscriber device  12  is in wireless electronic communication with a licensed wireless communication service that provides voice and/or data services. By way of example, the invention is disclosed in connection with a licensed wireless communication service in the form of a cellular network  14 . When the subscriber device  12  is within an unlicensed wireless service coverage area  16 , the licensed wireless service is substituted, without interruption, with an unlicensed wireless service that is facilitated through a base station  18 .  
         [0027]    The base station  18  wirelessly transmits telephone signals from a standard Public Switched Telephone Network (PSTN)  20  and, if necessary, a standard Private Base eXchange (PBX)  22 , to a subscriber device  12 . Specifically, when a device  12  is within an unlicensed wireless service coverage area  16 , the originating base station  18  provides the device  12  with wireless telephone service originating from a PSTN  20  rather than a cellular network  14 . Since the PSTN  20  is used, the subscriber device  12  receives high quality voice or data services at a relatively low cost. If the user of the subscriber device  12  roams outside of the unlicensed wireless service coverage area  16 , the same communication session can be maintained without interruption by transitioning to the licensed wireless service provided by the cellular network  14 . Techniques for implementing seamless transitions of this type are discussed in detail below.  
         [0028]    A system server  24  facilitates seamless transitions between the licensed wireless service and the unlicensed wireless service. The system server  24  is in electronic communication with the standard cellular network  14 . In one embodiment of the invention as shown in FIG. 1, the system server  24  is also in electronic communication with the base station  18  through a Local Area Network (LAN)  28  and a larger network  30 , such as the Internet. The system server  24  and the base station  18  may be linked through any number of communication services, including Digital Subscriber Line (DSL), cable, satellite, and the like.  
         [0029]    [0029]FIG. 1 illustrates that the cellular network  14  includes standard components, such as a cellular core network  15 , a Mobile Switching Center (MSC)  26 , Visitor Location Register (VLR)  32 , a Home Location Register (HLR)  34 , an Authentication Center (AC)  38 , and a Base Station Controller (BSC)  38 . As discussed below, these standard components are utilized in a novel manner in order to provide extended functionality for a subscriber device  12 .  
         [0030]    [0030]FIG. 2 illustrates a subscriber device  12 . As previously indicated, the subscriber device  12  may be a wireless telephone or a wireless modem. In the case of a wireless telephone, the subscriber device  12  includes a display  100 , keypad  102 , and a control circuit  104 . The display  100  may be used to provide a visual indication to a user when the subscriber device  12  is within the service range of the base station  18 . The keypad  102  is used in a conventional manner. The control circuit  104  may be in the form of a processor, a hardwired circuit, a programmable logic device, an application specific integrated circuit, and the like.  
         [0031]    The control circuit  104  is also connected to a memory module  106  and, via audio switch  108 , to an audio input/output circuit  110 . Wireless signals in the unlicensed spectrum are received by an antenna  110  and are filtered by a filter  112  to improve signal clarity and/or strength. The wireless signals are then processed by unlicensed wireless circuitry  114 , which is also referred to as unlicensed wireless communication signal processing circuitry. The unlicensed wireless circuitry operates as a standard transceiver for processing unlicensed wireless signals. The circuitry  114  may support any number of unlicensed wireless standards. For example, currently in the U.S., unlicensed wireless signals may be sent at frequencies around 900 MHz, 2.4 GHz, or 5 GHz. Unlicensed wireless communication may be implemented in accordance with the invention utilizing any number of unlicensed spectrum communications protocols, including Bluetooth, IEEE 802.11a, IEEE 802.11b, and Hyper-LAN. Advantageously, many licensed wireless subscriber devices are currently being configured to include unlicensed wireless circuitry for such applications as remote microphones and speakers. In accordance with the invention, this circuitry is used for a new application, namely, communicating with a base station, as discussed below.  
         [0032]    Selected signals, such as location update data or signal strength data, are sent to the control circuit  104 . Audio data is converted to an audio signal by audio circuitry  116  and is sent to an audio switch  108  for broadcast by an audio input/output circuit  109 . Audio signals transmitted to the audio input/output circuit  109  are transmitted by audio switch  108  to the control circuit  104 , which is capable of sending audio and other data to unlicensed wireless circuitry  114 . Unlicensed spectrum signals are then sent through the filter  112  and on to the antenna  110 , where they are broadcast to the base station  18 .  
         [0033]    In similar manner, wireless signals from a licensed cellular network  14  are transmitted to the antenna  111 , filtered by the filter  113 , and are then processed by the licensed wireless circuitry  118 , also referred to as licensed wireless communication signal processing circuitry. These signals are subsequently converted to an audio signal by audio circuitry  120  or are processed by control circuit  104 . As above, signals originating from the device  12  can also be sent out, but here the destination is a licensed wireless communication network (e.g., cellular network  14 ) rather than a base station  18 . In the event of a data modem, the audio input/output circuit  109  is omitted and a data source is applied directly to the control circuit  104 . Audio signals transmitted from the audio input  109  are transmitted by audio switch  108  to the control circuit  104 , which is capable of sending audio and other data to licensed wireless circuitry  118 . Wireless signals are then sent through the filter  113  to the antenna  111 , where they are broadcast to the licensed wireless network  14 .  
         [0034]    The individual subscriber device components discussed up to this point are standard. The combination of these devices is believed to be novel, as is the operation of these devices in accordance with a set of executable programs stored in memory  106 . The executable programs within memory  106  are shown by way of example. The same functionality may be realized through hardwired circuits, application specific integrated circuits, programmable logic devices, and the like. Indeed, the various components of the subscriber device  12  may be combined or integrated in any number of ways. The embodiment of FIG. 2 is for the purpose of illustration.  
         [0035]    The executable programs  106  reside on top of standard licensed wireless system call processing software. In addition, the programs  106  reside on top of standard unlicensed wireless link protocol software (e.g., standard Bluetooth or 802.11b software). The programs  106  bridge these systems by exchanging messages between the separate software stacks. Advantageously, this approach allows a large portion of the existing software protocols in the subscriber device  12  to be reused without any changes.  
         [0036]    The memory module  106  contains a location tracking module  122  that records the current location of the device  12  (i.e., whether the device is within an unlicensed coverage area  16 ). In addition, the module  106  contains an authentication and authorization module  124  to coordinate an authentication procedure for validating that the device  12  is licensed for use within the unlicensed coverage area  16 . As discussed below, the invention utilizes the authentication infrastructure associated with the licensed wireless system to authenticate and authorize a subscriber device for unlicensed wireless system services. The memory  106  also includes a handoff module  126  to coordinate seamless service exchanges between a base station  18  supporting unlicensed wireless communications and a licensed wireless communications network, such as a cellular network  14 . The operations associated with each of the modules stored in memory  106  are discussed in further detail below.  
         [0037]    [0037]FIG. 3 illustrates an embodiment of a base station  18  in accordance with an embodiment of the present invention. When the subscriber device  12  is within the coverage area  16  of the base station  18 , the base station  18  can be used to provide the subscriber device  12  with landline quality data and voice service via an unlicensed wireless communication link. In particular, the base station  18  interconnects to the existing telephone network to provide a final link to a subscriber device  12  through a short-range two-way radio link.  
         [0038]    In one embodiment of the invention, the base station  18  is controlled by a control circuit  200 , which is in communication with the LAN  28  and therefore the system server  24  via router jack  202  and/or Ethernet jack  204 . The control circuit  200  may be a processor, a hardwired circuit, a programmable logic device, an application specific integrated circuit and the like. Signals from the system server  24  travel through one of these jacks into network interface circuitry  206  and on to the control circuit  200 . This allows the base station  18  to communicate with the system server  24 . As discussed below, the server  24  determines whether and when to route phone service over the unlicensed wireless system (e.g., via the PSTN  20  and base station  18 ) or the licensed wireless system (e.g., via cellular network  14 ).  
         [0039]    The control circuit  200  is also in communication with a landline (PSTN  20  and, in the typical business context, PBX  22 ) via a phone line jack  208  and/or phone extension jack  210 . These jacks transmit information between the PSTN  20  and control circuit  200  through Plain Old Telephone Service (POTS) interface circuitry  212 . Audio data is translated by audio circuitry  214 , while other data can be directly exchanged with the control circuit  200 .  
         [0040]    The base station  18  communicates wirelessly with devices  12  using a radio frequency circuit  216 . This circuit  216  includes standard circuitry to receive and transmit electronic voice and/or data in an unlicensed wireless signal format. For example, currently in the U.S., unlicensed wireless signals may be sent in the frequency range between 2.4 GHz and 5 GHz. Unlicensed wireless communication may be implemented in accordance with the invention utilizing any number of unlicensed spectrum communications protocols, including Bluetooth, IEEE 802.11a, IEEE 802.11b, and Hyper-LAN.  
         [0041]    A typical circuit  216  consists of transmission circuitry  218  for transmitting signals to a device  12 , receiving circuitry  220  for receiving signals from the device  12 , and base band circuitry  222 . The baseband circuitry  222  contains standard circuitry for down converting unlicensed wireless signals to base band signals, which allows for the extraction of relevant information by the control circuit  200 . The base band circuitry  222  also contains standard circuitry for up converting base band data from the control circuit  200  to unlicensed wireless signals for broadcast by transmission circuitry  218 .  
         [0042]    The control circuit  200  is also connected to a memory module  224 . The memory module  224  contains a provisioning module  226  that is used to facilitate the initial configuration and servicing of the base station  18  and subscriber device  12 . The module  224  also includes a subscriber interface module  228 . The subscriber interface module  228  instructs the control circuit  200  to periodically broadcast a signal (e.g., an unlicensed wireless communication base station identification signal). If a subscriber device  12  responds to the signal, then the base station  18  knows that the subscriber device  12  is within the unlicensed coverage area  16 . The module  224  also contains an authentication module  230  to coordinate the authentication of a subscriber device  12  that has entered the unlicensed coverage area  16 . In one embodiment of the invention, the memory  224  includes an enhanced service module  232 . The enhanced service module may be used to provide improved services to a subscriber device. For example, if the user of a subscriber device is playing a low latency on-line game, different screen displays can be cached in the base station  18  and then be quickly downloaded to the subscriber device  12 . Each of the modules stored in memory  224  can also be implemented as hardwired circuits, application specific integrated circuits, programmable logic devices, and the like.  
         [0043]    The enhanced service module  232  may also be used to implement other advanced features. For example, the enhanced service module  232  can be configured to append a set of prefix digits before dialed digits to instruct the server  24  to route long distance calls on a specific service provider network.  
         [0044]    The enhanced service module  232  can also be used to simultaneously support multiple subscribers. For example, the base station  18  may support multiple subscriber devices through a single or multiple landline connections.  
         [0045]    Preferably, the subscriber interface module  228  of the base station  18  is configured to advise a subscriber device when the landline associated with the base station  18  is occupied. In such a case, the handoff module  126  of the subscriber device will no longer attempt to make contact with the base station  18 , but will continue to utilize the licensed wireless system for call servicing.  
         [0046]    In order to provide landline-quality service to subscriber devices  12 , a base station  18  is installed directly in the path of a typical phone system. FIG. 4A illustrates a typical office or workplace, where a telephone  300  is connected to a PBX  22 . The PBX  22  is installed between the telephone  300  and PSTN  20  to provide a private telephone network in which a number of telephones  300  share a certain number of outside lines from the PSTN  20 . FIG. 4A illustrates that a Personal Computer (PC)  302  can be connected to the LAN  28  for communication with the Internet  30 .  
         [0047]    [0047]FIG. 4B illustrates the workplace environment of FIG. 4A modified to incorporate the base station  18  of the invention. The base station  18  is placed in electronic communication with both the telephone  300  (e.g., via phone line jack  208 ) and the LAN  28  (e.g., via Ethernet jack  204 ). This configuration allows base station  18  to receive landline voice and data from a PSTN  20  and broadcast it to subscriber devices  12  when they are within the coverage area  16 . The base station  18  is also connected to a LAN  28 , which allows it to communicate with the system server  24  in order to coordinate handoffs between the licensed wireless and unlicensed wireless systems. Advantageously, the base station  18  operates transparently with respect to the PBX  22 , the LAN  28 , the telephone  300 , and the PC  302 . In the event that the PBX  22  is Internet Protocol based, the base station  18  can be connected solely to the LAN  28 .  
         [0048]    [0048]FIG. 4C illustrates a typical home setting, which is usually similar to the workplace setting of FIG. 4A minus the LAN  28  and PBX  22 . The telephone  300  is ordinarily connected directly with Plain Old Telephone Service (POTS)  304 , which is simply another term for PSTN  20 . Connection to the Internet  30  is provided by a modem  306  in communication with a PC  302 . FIG. 4D illustrates the placement of base station  18  within this typical home setting. Here, the base station  18  is placed in electronic communication with both a telephone  300  and modem  306 , allowing it to communicate directly with the POTS  304 /PSTN  20  and, through modem  306 , with the Internet  30  and system server  24 . Once again, the base station  18  operates transparently with respect to the modem  306 , the POTS  304 , the telephone  300 , and the PC  302 .  
         [0049]    In both the workplace and home settings, the base station  18  can be in simultaneous communication with both a telephone landline and a system server  24 . When a subscriber device  12  roams inside the coverage area  16 , the base station  18  can thus provide landline-quality service to device  12 . The invention should thus be construed to include an apparatus and method for the seamless switching of telephone service between a cellular network  14  and a landline-based base station  18  that can be used in either a residential or commercial setting.  
         [0050]    As mentioned above, for purposes of this invention a landline can be interchangeably referred to as a POTS  304  or PSTN  20 . However, the invention should not be construed as limited to simply the POTS or PSTN context. Rather, the invention discloses a base station  18  that can provide landline-quality service to a subscriber device  12  by communicating with any landline network. Examples of such networks include, but are not limited to, DSL, cable or cable modem networks.  
         [0051]    [0051]FIG. 5 illustrates a system server  24 , which manages the mobility of subscriber devices  12  between a landline-based unlicensed wireless service from a base station  18  and a licensed wireless service, such as from a cellular network  14 . A typical system server  24  is controlled by a central processing unit (CPU)  400 , which is connected to a bus  401 . Network interface cards  402  (e.g., Ethernet cards) for communicating with the Internet  30  are also connected to the bus  401 . Licensed network interface cards  404  (e.g., SS7 cards) for communicating with cellular networks  14  are also connected to the bus  401 . This allows the system server  24  to use Internet Protocol (IP) and/or SS7 protocol and/or MAP &amp; IS-41 protocols to connect to the Internet and cellular core networks.  
         [0052]    The system server  24  also contains a memory module  406  that stores a number of programs, databases and other assorted modules. More specifically, the module  406  contains signaling control programs  408 . The signaling control programs  408  are standard programs for establishing communications with the licensed wireless network. Therefore, for example, the signaling control programs  408  may include a Transaction Capability Application Part (TCAP) module, a Message Transfer Part (MTP) module, and an Interim Standard (IS41) module to support Time Division Multiple Access (TDMA) and Code Division Multiple Access (CDMA). Memory  46  may also store datapath control programs  410 . By way of example, the datapath control programs may include standard programs to facilitate computer network data transfers. By way of example, the datapath control programs may include an Internet Protocol (IP) module and a Gateway Tunnel Protocol (GTP) module.  
         [0053]    The memory  406  also stores various system server application programs  412 . These application programs include system bridge programs  414  for handling transitions in service from licensed to unlicensed wireless services and vice versa. The memory  406  also stores a location database  416  for storing the current location of devices  12  and indicating whether they are within the coverage area  16 . Also included is a billing module  418  for recording usage statistics for billing purposes. The billing module  418  distinguishes between charges for licensed wireless services and unlicensed wireless services. A provisioning module  420  is included to facilitate the installation of new base stations. An authentication module  422  is used to facilitate the authentication of a subscriber device within an unlicensed wireless service area. As discussed below, the authentication module  422  includes data and executable instructions to emulate certain components of a licensed wireless network. For example, the authentication module emulates a mobile switching center during the authentication process.  
         [0054]    The major components of the invention—the subscriber device  12 , the base station  18 , and the system server  24 —have now been described. The operations of these devices are more fully appreciated with the following discussion.  
         [0055]    The invention&#39;s facilitation of seamless transitions between licensed and unlicensed wireless services is more fully appreciated in connection with FIG. 6. Base station  18  broadcasts within a set of boundaries B 1 , B 2 , B 3  and B 4 . A subscriber device  12  located outside these boundaries is serviced by a licensed wireless system, such as a standard cellular network  14 . However, once the device  12  crosses boundary B 3 , the handoff from the licensed wireless service to the unlicensed wireless service begins. That is, at the B 3  boundary the base station  18  is able to recognize the presence of the subscriber device  12 . As previously indicated, the base station  18  includes a subscriber interface module  228  that coordinates the transmission of a service range signal that is identified by a subscriber device  12 . That is, the location tracking module  122  of the subscriber device  12  is used to coordinate the identification of a base station signal. In the presence of such a signal, the location tracking module  122  coordinates the transmittal of an acknowledgment signal to the base station  18 .  
         [0056]    Preferably, the subscriber interface module  228  of the base station  18  identifies the boundary points of the service area  16  by using the received signal strength and the transmit-power level setting from the subscriber device  12 . In particular, an automated process is preferably used to learn the boundary distances through heuristically measuring the success rate and adjusting the boundary distance for optimal handoff success rates.  
         [0057]    In one embodiment, the location tracking module  122  of the subscriber device  12  is implemented to periodically wake the unlicensed wireless circuitry  114  to sniff and thereby determine whether it is within the range of a base station. If so, the subscriber device registers with the base station  18 , if not, the unlicensed wireless circuitry  114  is activated at a later time.  
         [0058]    Under the control of the subscriber interface module  228 , the base station  18  identifies the acknowledgement signal and transmits a subscriber device present signal to the router jack  202 , the Ethernet jack  204 , the phone line jack  208 , or the phone extension jack  210 . The subscriber device present signal is subsequently directed through a network (e.g., the LAN  28  and Internet  30 ) to the system server  24 , which notes that the subscriber device  12  is now within the service area of the base station  18 . In particular, the system server  24  logs this information in the location database  416 .  
         [0059]    Once the system server  24  logs the fact that the subscriber device  12  is within the service range of the base station  18 , it contacts the cellular network  14  to initiate a call to the landline associated with the base station  18 . It is known in the art to utilize a cellular network  14  to establish a call to a landline number. For example, FIG. 1 illustrates a link between the Mobile Switch Center (MSC)  26  and the PSTN  22 . In the prior art, this feature is used to direct a call intended for a mobile device to a landline telephone when the user of the mobile device has advised the cellular system that the landline telephone can be used to receive calls. Observe in this situation that the transition from the cellular network to the landline telephone is established prior to the call being placed. This prior art scenario stands in sharp contrast to the present invention where during the course of an already established communication session control is transferred from a licensed wireless service to an unlicensed wireless service or vice versa. This aspect of the invention is more fully appreciated in connection with the following discussion.  
         [0060]    As previously indicated, when the subscriber device  12  crosses the boundary B 3 , a landline call to or from the base station  18  is initiated. Once the landline call is received at the base station  18 , the base station  18  begins transmitting to the subscriber device  12  using the unlicensed wireless spectrum. These transmissions are processed by the unlicensed wireless circuitry  114  of the subscriber device  12  (See FIG. 2). At this point, the licensed wireless circuitry  118  is also active and the audio switch  108  is responsive to the licensed wireless circuitry  118 . Thus, the subscriber device  12  is processing both licensed wireless signals and unlicensed wireless signals at this point. The handoff module  126  can coordinate this operation.  
         [0061]    The subscriber interface module  228  of the base station  18  continues to monitor the signal strength from the subscriber device  12 . When the signal strength reaches a threshold corresponding to the crossing of boundary B 4 , the subscriber interface module  228  initiates a handoff command, which is applied to the RF circuit  216 . The handoff command is received at the subscriber device  12  and is processed by the handoff module  126 , which generates a handoff signal that is applied to the audio switch  108 . The handoff signal causes the audio switch  108  to process information from the audio circuitry  116  associated with the unlicensed wireless circuitry  114 .  
         [0062]    At this point, the licensed wireless circuitry  118  can be turned off. The ability to turn this circuitry off is a significant advantage because it preserves battery life. Typically, the licensed wireless circuitry remains active in order to provide location information to the licensed wireless system infrastructure. However, as discussed below, this location information is available in accordance with the invention. Therefore, the licensed wireless circuitry can be shut down to obtain a significant extension in battery life. Alternately, the licensed wireless circuitry  118  can remain in a low power state to receive signaling or messages from the licensed wireless system, while voice is carried over the unlicensed system.  
         [0063]    The spacing between boundaries B 3  and B 4  allows time for the establishment of simultaneous connections between the subscriber device  12  and both the licensed network and unlicensed network. This allows for the immediate switching of service to the unlicensed network once the subscriber device  12  crosses boundary B 4 , thus creating a seamless transition to base station service that is transparent to the user.  
         [0064]    Once the device  12  is within boundary B 4 , service is originated within the PSTN  20  and broadcast wirelessly to the device  12  by the base station  18 . If the device  12  travels away from this base station  18 , service is handed off from the base station  18  to a licensed wireless network  14  in a manner similar to the process described above. Specifically, once the device  12  crosses boundary B 2 , a simultaneous link is established with a licensed wireless network (e.g., cellular network  14 ). When the device  12  further crosses boundary B 1 , a seamless handoff is made from the unlicensed wireless service originating over the PSTN  20  to the licensed wireless network (e.g., cellular network  14 ). At this point, the subscriber device  12  receives wireless services from the cellular network  14  in a standard manner.  
         [0065]    [0065]FIG. 7 provides a more detailed characterization of this handoff process from an unlicensed wireless service to a licensed wireless service. When the subscriber device  12  is within the service area  16  of the base station  18 , the subscriber device  12  transmits to the base station  18  information on the signal strengths of the frequencies of the nearby licensed wireless base stations. The base station  18  forwards this information to the system server  24 , which in turn sends the information to the Visitor Location Register (VLR)  32 . This operation is shown with arrow  450  in FIG. 7.  
         [0066]    In response to this message, the licensed wireless system provides the parameters that are needed when the subscriber device  12  needs a handoff from the unlicensed wireless system to the licensed wireless system. This information includes the identity of the base station to which the handoff should be made. By way of example, in a GSM cellular system, these parameters are CI (Cell Identity) and LAC (Location Area Code). This handoff information may be obtained and stored in the base station  18  before a call is made or when a call is made. In any event, the handoff information can be secured well before the subscriber device  12  roams outside the coverage area of the base station  18 . The availability of this information allows the subscriber device  12  to quickly transition to the licensed wireless system. In addition, this information allows the licensed wireless circuitry  118  to be shut down for the purpose of extending battery life.  
         [0067]    The licensed wireless system connection information may be delivered to the base station  18  via a landline connection as shown with line  452 . Alternately, the information may be delivered through a communication session between the system server  24  and the mobile switch center  26  and then the system server  24  and the base station  18 , as shown with arrows  454  and  456 .  
         [0068]    As shown with arrow  458  in FIG. 7, the base station  18  continuously makes power measurements of signals that are received from the subscriber device  12 . When the power measurements begin to grow weak, the base station may notify the system server  24  to initiate a handoff to the licensed wireless system. In turn, the system server  24  may advise the Mobile Switch Center (MSC)  26  of the hand over candidate, as shown with arrows  460  and  462 .  
         [0069]    When the power measurements at the base station  18  become sufficiently weak, indicating that the subscriber device  12  is moving away from the base station  18  (e.g., crossing boundary B 2 ) a formal hand over request is initiated. In particular, the base station  18  transmits to the system server  24  the base station identity (e.g., CI, LAC, etc.) to which the handoff should be transferred, as shown with arrow  458 . The system server  24  contacts the MSC  26  to initiate a handoff, as shown with arrow  460 . The MSC  26  contacts the Base Station Controller (BSC)  38 , as shown with arrow  462 . In response, the BSC  38  generates a channel number, a slot number and a handoff reference. As shown with arrow  464 , this information is passed to the Base Station Transceiver System (BTS)  500 . The information is also passed back to the subscriber device  12  through the MSC  26 , the system server  24 , and the base station  18 , as shown with arrows  466 ,  468 ,  470 , and  472 .  
         [0070]    In response to this information, the BTS  500  turns on a transmitter and receiver at the specified channel number and slot number. Similarly, the subscriber device  12  turns on its transceiver circuitry  118 . The BTS  500  seeks a response from the subscriber device with a matching reference number, as shown with arrow  474 . Once the subscriber device  12  receives the BTS transmission, it sends a message to the BTS with the handoff reference, as shown with arrow  476 . At this point, a new licensed wireless link is established on the given channel and slot number, as shown with arrow  478 . Once the licensed wireless link is established, the unlicensed wireless link is turned off, as shown with line  480  in FIG. 7. Thereafter, the BTS  500 , the BSC  38 , and the MSC  26  operate in a standard manner to supply licensed wireless services to the subscriber device  12 . The foregoing operations may be implemented using the handoff module  126  of the subscriber device  12 , the subscriber interface module  228  of the base station  18 , and the system bridge programs  414  of the system server  24 .  
         [0071]    As previously indicated, a handoff from a licensed wireless service to an unlicensed wireless service occurs in a similar but reverse fashion. When the subscriber devices  12  cross boundary B 3  from a remote location the base station  18  initiates a handoff operation by sending a request to the system server  24 , which conveys the request to the MSC  26 . The MSC  26  then hands off the call to the landline number assigned to the base station  18 .  
         [0072]    Between boundaries B 3  and B 4 , both the licensed wireless (e.g., cellular) link and unlicensed wireless (e.g., landline originated) link are simultaneously active. After a period in which both links are simultaneously active, control of the communication session is switched from the licensed wireless circuitry  118  to the unlicensed wireless circuitry  114 . The handoff module  126  may coordinate this handoff in response to a handoff command initiated at the subscriber interface module  228  of the base station  18 . As above, the maintenance of simultaneous licensed and unlicensed wireless links for a period of time ensures a successful seamless handoff. This reduces the number of dropped calls, and allows for successful handoffs even when the signaling messages among different elements of the cellular and landline-based systems experience delays or latency.  
         [0073]    The foregoing discussion was directed toward handoffs between licensed wireless services and unlicensed wireless services. The invention also includes a technique for seamless handoffs between unlicensed wireless service base stations. Such a technique would be valuable, for example, in the case where an office building has a large number of base stations  18  to supply unlicensed wireless services to a user that would otherwise receive poor quality licensed wireless service within the office building.  
         [0074]    Thus, the invention includes a system wherein a plurality of base stations  18  exist with overlapping coverage areas  16 . This allows a subscriber device  12  to roam freely among the coverage areas  16 .  
         [0075]    [0075]FIG. 8 illustrates such a system. The subscriber device  12  is registered with base stations  600  and  602 . Base stations  600  and  602  communicate with each other using LAN  28 . The base stations  600  and  602  are shown installed in a typical workplace setting, with telephones  300  and PCs  302  connected to a LAN  28  and PBX  22  in a standard fashion. Note that the coverage areas  604  and  606  of the base stations  600  and  602  overlap. As a device  12  moves from one area  604  to another area  606 , voice and data signals from the first base station  600  are seamlessly handed off to the second base station  602 .  
         [0076]    Periodically, the base stations  600  and  602  broadcast a message over the LAN  28  to all other base stations connected to the LAN  28 . This message includes a time stamp, a signal indicating the particular base station, the subscriber number, and a range number indicating the distance between that base station and the device  12 . A separate message is broadcast for each base station on the LAN  28 . A range number can be calculated by relying upon the ability of the base station  18  to measure the signal strengths emitted from the subscriber device or vice versa.  
         [0077]    In accordance with this feature of the invention, there is no centralized control mechanism for handling handoffs. Instead, the subscriber interface module  228  of each base station  18  is used to coordinate handoffs between base stations based upon signal strengths and/or range numbers. For example, in FIG. 8, at position T 1  the base station  600  would transmit a time stamp, a base station number, a subscriber number, and a range number indicating that the subscriber device  12  is relatively close to the base station  600 . At T 2  the base station  600  would transmit the same information except a different range number indicating that the signal between the base station  18  and the subscriber device  12  is weaker. By position T 3 , the base station  602  would send a signal on the LAN  28  indicating that it has a range number indicating that the subscriber device  12  is now closer to it than to base station  600 . Accordingly, both base stations would recognize that a transition from base station  600  to base station  602  should transpire. Under these circumstances, the second base station  602  transmits a signal over LAN  28  to the first base station  600  requesting a transition. Once the first base station  600  acknowledges this request, it forwards the call to the second base station  602  and service is continued without disruption. For example, the call may be forwarded over LAN  28  using Voice Over Internet Protocol (VOIP) techniques.  
         [0078]    The discussion up to this point has been directed toward seamless transitions between licensed and unlicensed wireless services. Attention now turns to other aspects of the invention. Another aspect of the invention is a technique for assigning a base station to a landline telephone number. Another aspect of the invention is a technique for authenticating a user for unlicensed wireless services. Advantageously, authentication is implemented through reliance upon existing authentication infrastructure associated with the licensed wireless network. Thus, a separate authentication scheme need not be implemented. Another aspect of the invention that is discussed below is the provisioning of a base station into the overall licensed wireless network. As discussed below, the provisioning operation is automatically performed and therefore does not require technical sophistication or expertise on behalf of the user.  
         [0079]    [0079]FIG. 9 illustrates a technique for assigning a landline number to a base station  18 . Upon installation and power-up, the base station  18  queries the subscriber device  12  for the local landline phone number to which the base station is connected. In some embodiments, the base station  12  will also solicit the Internet Protocol (IP) address for the system server  24 . After the user enters the phone number and/or IP address into the subscriber device  12 , the information is transmitted to the base station  18 , as shown with arrow  610  of FIG. 9. The base station  18  forwards the same information to the system server  24 , as shown with arrow  612 . The system server  24  then transmits this information for storage in the HLR  34 , as shown with arrow  614 . Once stored in the HLR  34 , the MSC  26  can access the number as a mobile system roaming number (MSRN), as shown with arrows  616  and  618 . Thereafter, the mobile system roaming number can be used in a conventional manner to route a call to the base station  18 . Alternately, the MSRN may be a number corresponding to a number associated with the system server  24 . In which case, the system server  24  sends the call to the base station  18 .  
         [0080]    Another aspect of the invention is authentication. As previously indicated, the invention utilizes the authentication infrastructure associated with the licensed wireless network to authenticate users for the unlicensed wireless network.  
         [0081]    [0081]FIG. 10 illustrates a licensed wireless system authentication process utilized in accordance with the prior art. In this example, the subscriber device  12  moves from the coverage area served by its home MSC (referred to as MSC-A) to the coverage area served by MSC-B. As soon as the subscriber device  12  enters a cell that is served by MSC-B, it registered with the system by sending an authentication request and a location update to BSS  600 , as shown with arrow  650 . The location update request includes an international mobile subscriber identity (IMSI).  
         [0082]    BSS  600  forwards this information to the VLR  32  associated with MSC-B, as shown with arrow  652 . The VLR of MSC-B in turn sends a message to the VLR and HLR of the SMC-A, as shown with arrows  654  and  656 . This information serves as a request for authentication of the subscriber device  12  as well as to inform the HLR  34  of the current location of the subscriber device  12  as served by the MSC-B. The authentication is performed as follows.  
         [0083]    The authentication center (AuC)  36  generates a parameter called SRES (signed response). In order to generate the SRES, it uses an authentication algorithm A3, such as a public key/private key algorithm. The algorithm A3 processes a secret key Ki, a random number RAND, and the IMSI to produce the SRES. The IMSI, RAND, and SRES are passed to the MSC-A (arrow  658 ) and MSC-B (arrow  660 ). The SRES is temporarily stored at the MSC-B until the authentication operation is completed. The MSC-B passes the IMSI and the RAND to the BSS, which passes the information to the subscriber device  12 . Based upon the IMSI and the RAND that it receives (referred to herein as licensed wireless communication system security information), along with the secret key Ki that it stores, the subscriber device  12  executes the same authentication algorithm A3. This results in the subscriber device  12  producing a SRES, which is referred to as an authentication result. If the subscriber device is legitimate, it has the same secret key Ki encoded in it as the one in the HLR. The service provider encodes this key at the time of activating the subscriber. This key is known only to the subscriber device and to the HLR.  
         [0084]    The SRES, or authentication result, generated by the subscriber device  12  is passed with the IMSI to the BSS-B (arrow  666 ), which passes it to the MSC-B (arrow  668 ). The MSC-B compares the SRES generated by the subscriber device  12  to the SRES generated by the HLR. Authentication is only successful if the two numbers match. The SRES generated by the HLR can be referred to as an authentication value. If the authentication value from the HLR matches the authentication result from the subscriber device  12 , then an authentication command is generated.  
         [0085]    The above process assists in understanding the authentication process included in the present invention, as the new method is designed to utilize the existing authentication process already existent in the licensed wireless system. FIG. 11 illustrates an authentication process in accordance with the present invention. In accordance with the invention, the base station  18  is designed to emulate a BSS  600 , and the system server  24  is designed to emulate an MSC  26 .  
         [0086]    When the subscriber device  12  enters the service area of the base station  18 , it registers with the base station. The authentication module  124  of the subscriber device  12  subsequently intercepts the registration message that is typically sent to the licensed wireless base station (e.g., BSS  600 ). This information, referred to as a licensed wireless authentication request, is sent to the base station  18 , as shown with arrow  680 . The base station  18 , at the direction of the authentication module  230 , routes the information to the system server  24 . In particular, the authentication module  230  of the base station  18  forms an Internet Protocol (IP) packet containing the information and routes it to the system server  24 . As shown with arrow  684 , the system server  24  forwards the information to the MSC-A. The authentication module  422  of the system server  24  may be used for this purpose. In this capacity, the authentication module  44  assists the system server  24  in its operation of emulating a VLR. The operations at arrows  656 ,  658 , and  660  are identical to the operations performed in the prior art system of FIG. 10.  
         [0087]    At this point, the system server  24  stores the SRES, instead of an MSC. The system server  24  forwards the IMSI and RAND information to the base station  18 , as shown with arrow  686 . The base station  18 , emulating a BSS, passes this information to the subscriber device  12 . The authentication operation performed at the subscriber device is conventional, with the subscriber device returning an authentication result (e.g., an IMSI and a SRES) to the base station  18 , as shown with arrow  690 . The base station  18  passes this information to the system server  24 , as shown with arrow  692 . The system server  24  then checks for an SRES match. That is, the system server compares the authentication result produced by the subscriber device  12  to the authentication value (e.g., SRES) received from the MSC-A. Recall that this operation was performed by the MSC  26  in the prior art system of FIG. 10. In the event of a match between the computed SRES values, an authentication command is produced and unlicensed wireless services may be delivered to the subscriber device  12  through the base station  18 .  
         [0088]    Preferably, authentication is not performed every time the subscriber device registers with the base station  18 . Instead, the authentication module  230  of the base station  18  preferably stores previous authentication information and locally re-authenticates without accessing the system server  24 . This implementation is faster and otherwise reduces network traffic.  
         [0089]    Yet another aspect of the invention involves provisioning of a base station in order to facilitate the licensed-to-unlicensed wireless communications achieved in accordance with the invention. By way of overview, the provisioning operation of the invention entails the base station  18  automatically configuring itself. In one embodiment, provisioning is accomplished by initially accessing a provisioning server. Subsequently, the base station registers with the system server. In the event that Internet access is available to the base station, the base station uses the Internet to access the provisioning server and the system server. If Internet access is not available, a Short Message Service Center may be used during the provisioning operation.  
         [0090]    [0090]FIG. 12 illustrates equipment utilized during the provisioning operation. In particular, the figure illustrates a subscriber device  12  and a base station  18 . In one embodiment, the base station  18  uses the Internet  30  to access a provisioning server  700 . For example, the base station  18  may access the Internet through a broadband modem, such as DSL. The provisioning server  700  supplies a service profile to the system server  24 , as discussed more fully below. In another embodiment of the invention, the base station  18  is provisioned through a wireless connection. In particular, a wireless link is established using a Short Messaging Service or packet data services supported by the cellular system. For example, a short messaging service message can be sent from the base station  18  to the subscriber device  12 , which then delivers the message to the BSS  600 . The BSS  600  delivers the message to the cellular network  14 , which delivers the message to the MSC  26 . The MSC  26  routes the message to the Short Message Service Center (SMSC)  702 , which routes the message over the Internet  30  to the provisioning server  700 . Information from the provisioning server  700  is delivered to the system server  24  and the base station  18  through a reverse path.  
         [0091]    [0091]FIG. 13 illustrates the process steps involved when the system of FIG. 12 carries out the provisioning process. The process is typically initiated upon installation and activation of a new base station  18 , and will be discussed in that context, but those of skill in the art will see that it can be performed any time that provisioning information must be updated.  
         [0092]    When a base station  18  is initially powered up it contacts the provisioning server  700  (step  800 ). The provisioning module  226  of the base station  18  coordinates this operation. In one embodiment, contact is made through the Internet  30  using one or more preprogrammed IP addresses for the provisioning server. Alternately, the provisioning server may be accessed through the SMSC, as discussed above. The base station  18  then identifies itself to the provisioning server  700 , for example, using a code preprogrammed at the time of manufacture. If the provisioning server  700  does not recognize the base station, the base station preferably provides an error indication. If the provisioning server  700  recognizes the base station, that processing proceeds to block  806 .  
         [0093]    At this point, the base station broadcasts a signal to the subscriber device  12  instructing it to define itself (block  806 ). For example, the subscriber device  12  may define itself by sending to the base station  18  an electronic serial number or a portion of an electronic serial number. This defining information is used to establish an association between the base station  18  and the subscribe device  12 . This local association is mapped with a local authentication procedure. Thereafter, whenever the subscriber device and the base station come into contact, they identify each other by passing the local authentication procedure. The two devices can only communicate if the local authentication procedure is successful.  
         [0094]    The provisioning module  127  of the subscriber device  12  prompts the user to enter the landline telephone number associated with the base station  18  (block  808 ). This information is then passed to the base station  18 . The base station then delivers information to the provisioning server (block  810 ). For example, the base station will typically deliver the landline telephone number and a base station identification number to the provisioning server. The provisioning server then downloads a service profile to the base station and the system server (block  812 ). The service profile can include the landline telephone number and caller services, such as call waiting, caller identification, and the like. The service profile may also include an IP address for the base station. The IP address allows packet data to be delivered to the base station. The service profile also includes the IP address of a system server  24  assigned to the base station  18 . Typically, the system server  24  is selected based upon proximity to the base station, as derived from the area code associated with the landline telephone number.  
         [0095]    Observe that the provisioning server operates as a central registration point for all devices within the system. This central point makes it easier to modify system wide services. In addition, the provisioning server provides the benefit that a single address is programmed into each base station.  
         [0096]    The base station takes the IP address of the system server from the service profile and contacts the system server (block  814 ). If the service profiles match, an association is established between the system server, the base station, and the subscriber device. The system server subsequently updates the HLR of the subscriber device with contents of the service profile (block  816 ). At this point, the authentication process of FIG. 11 would typically be performed. This provisioning process can be repeated whenever a new device  12  or base station  18  is introduced into the system.  
         [0097]    Another aspect of the invention allows licensed wireless service users to seamlessly change between a desktop phone and a subscriber device  12  during a call, thus allowing them to use the most comfortable device at a given time. Thus, when a subscriber device  12  is located within a coverage area  16 , a user can simply pick up the desktop phone and continue their conversation. The subscriber device  12  can then be disconnected without any interruption in service. In this embodiment, the desktop phone and the base station are connected to the same landline, thereby providing this interchangeability. Likewise, when a caller is using a desktop phone within an area  16 , he or she can activate a subscriber device  12  and continue a call from there. In this instance, a button on the subscriber device is used to initiate communication with the base station that is connected to same landline. Subsequently hanging up the desktop phone will not interrupt service. Observe in this context that when the subscriber device is within the coverage area  16  of the base station  18 , both the subscriber device  12  and a desktop telephone may simultaneously ring in response to a call. The user can then pick up either device.  
         [0098]    The foregoing description, for purposes of explanation, used specific nomenclature to provide a through understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order to practice the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed; obviously, many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, the thereby enable other skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention.