Abstract:
Systems and methods for providing dispatch call features are provided. The dispatch call features include the ability to maintain multiple simultaneous dispatch calls and the ability to manage multiple dispatch stations. The maintenance of multiple simultaneous dispatch calls feature allows a dispatch station to place a current dispatch call on-hold to either initiate a new dispatch call or to accept an incoming dispatch call. The management of multiple dispatch stations feature allows a number of dispatch stations to be associated with one or more dispatch station identifiers. When a dispatch call is made to one of the dispatch station identifiers, all associated dispatch stations are paged. The first dispatch station to respond to the page is connected to the incoming dispatch call.

Description:
The present application claims priority under 35 U.S.C. §119 to U.S. Provisional Application No. 60/691,862, filed Jun. 18, 2005, and is related to U.S. patent application Ser. No. 11/227,358, filed Sep. 15, 2005 and U.S. patent application Ser. No. 11/294,396, filed Dec. 6, 2005, the entire disclosure of these documents is herein expressly incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The mobility afforded by wireless communication networks has resulted in increased usage of such networks. Wireless networks can be divided into private wireless networks and publicly-accessible wireless networks. Private wireless networks, also known as private trunking radio networks, are commonly operated by public safety agencies, taxi services and delivery services. A majority of private wireless networks provide only dispatch communication services, whereas a majority of publicly-accessible wireless networks provide only interconnect communication services. Some publicly-accessible wireless networks, however, provide both interconnect and dispatch communication services. Dispatch communication services are sometimes referred to as “walkie-talkie” communication services because of the half-duplex nature of the communications. Interconnect communication services are what is typically referred to as circuit-switched voice communications, and are full-duplex. 
     Private wireless networks typically operate over a limited range of frequencies and within limited geographic areas. Additionally, private wireless networks typically operate using proprietary protocols, have limited expansion capabilities, are expensive to operate and cannot easily interoperate with other private or publicly-accessible wireless networks. In contrast, publicly-accessible wireless networks typically operate over a larger number of frequencies and provide coverage over larger geographic areas. Moreover, publicly-accessible wireless networks use standard protocols, are easier to expand, and interoperate with other publicly-accessible wireless networks. 
     Due to the relative complexity of publicly-accessible dispatch communication networks compared to private dispatch communication networks, some of the features and functionalities provided in private dispatch communication networks are not offered in publicly-accessible dispatch communication networks. Specifically, private dispatch communication networks typically have a single, centrally-located, communications processor (or call handler) for managing and routing communications between wireless stations. In contrast, publicly-accessible dispatch communication networks have a distributed architecture which involves routing communications between a number of communication processors. Moreover, due to the differences between interconnect and dispatch communication services, many features provided for interconnect communication services are not available for dispatch communication services. 
     SUMMARY OF THE INVENTION 
     The present invention provides systems and methods for dispatch calling features. These calling features include the ability to conduct multiple simultaneous dispatch calls and the management of multiple dispatch stations. In conventional communication systems when a dispatch station is engaged in a dispatch call, the current call must be disconnected before initiating a second call, and the dispatch station is not notified of incoming dispatch calls. In accordance with exemplary embodiments of the present invention, a dispatch station can place a current dispatch call on-hold and initiate a second dispatch call. The dispatch station can freely switch between the dispatch calls. Moreover, when a dispatch station is engaged in a dispatch call, the dispatch station can be notified of the incoming dispatch call and provided with an option to place the current call on-hold and connect to the incoming call. Again, the dispatch station can freely switch between the dispatch calls. 
     Conventional communication systems also do not provide a way to manage multiple dispatch stations. For example, a user may have a number of dispatch stations, each with a different dispatch station identifier, e.g., a calling address. Due to the limitations of conventional communication systems, the user may miss incoming dispatch calls unless the user carries each of the multiple dispatch stations. In accordance with exemplary embodiments of the present invention, a number of dispatch stations can be associated with one or more dispatch station identifiers. When a dispatch call is initiated to one of the dispatch station identifiers, all of the associated dispatch stations are paged. The first dispatch station to respond to the page will continue on the dispatch call, and the paging procedure for the other dispatch stations will be terminated. 
     Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         FIGS. 1   a  and  1   b  are block diagrams illustrating exemplary systems in accordance with the present invention; 
         FIG. 2  illustrates an exemplary dispatch call handler in accordance with the present invention; 
         FIG. 3  is a flow chart illustrating an exemplary method for dispatch call paging to multiple dispatch stations in accordance with the present invention; and 
         FIG. 4  is a flow chart illustrating an exemplary method for managing multiple dispatch calls in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1   a  illustrates an exemplary system  100  in accordance with the present invention. The system  100  includes a dispatch area network subsystem  110  and a radio access network (RAN)  130 . A dispatch area is a geographic area which includes two or more cells that share network subsystems, such as mobile switching centers (MSCs) and location registers. The dispatch area network subsystem  110  includes a call register  112 , and first and second dispatch call handlers  114  and  116 . The call register  112  generally operates in a similar manner to a location register and performs the functions of a home location register (HLR) to register and authenticate the user. Each call handler generally operates in a similar manner to an MSC/visitor location register (MSC/VLR) or a dispatch application processor (DAP). 
     The first dispatch call handler supports communications from dispatch stations  132  and  134 , and the second dispatch call handler supports communications from dispatch stations  136  and  138 . As used herein, a dispatch station is capable of at least dispatch communications, and if properly equipped, can perform interconnect and/or data communications. These dispatch stations can be wireless telephones, personal digital assistants (PDAs), laptop computers and/or the like. 
     The system also includes a dispatch console  140  which connects to dispatch call handler  114  via the Internet  142 , thereby allowing the dispatch console to perform dispatch communications with the wireless dispatch stations  132 - 138 . Dispatch console  140  can be a console dedicated to dispatch communications, a general purpose computer executing a program for dispatch communications, or the like. 
       FIG. 1   b  illustrates an exemplary system  150  in accordance with another embodiment of the present invention. The system illustrated in  FIG. 1   b  is similar to the system illustrated in  FIG. 1   a , and hence, like elements include the same reference numbers. The difference between the systems of  FIGS. 1   a  and  1   b  is that in  FIG. 1   a  the first and second dispatch call handlers  114  and  116  are located in the same dispatch area network subsystem  110 , whereas in  FIG. 1   b , the first and second dispatch call handlers are located in different dispatch area network subsystems  110  and  160 . Because the second dispatch call handler  164  is located in a different dispatch area network subsystem than the first dispatch call handler  114 , the second dispatch call handler uses a different call register and RAN, i.e., call register  162  and RAN  165 . 
       FIG. 2  illustrates an exemplary dispatch call handler in accordance with the present invention. The dispatch call handler  200  includes processor  205  and memory  210 . Processor  205  includes multiple dispatch station paging arbitration logic  215 , which will be described in more detail below in connection with the method of  FIG. 3 , and simultaneous dispatch call logic  220 , which will be described in more detail below in connection with the method of  FIG. 4 . The processor can be a microprocessor, field programmable gate array (FPGA), application specific integrated circuit (ASIC) and/or the like. Memory  210  can be any type of memory including volatile or non-volatile memory, flash memory or a hard disk, random access memory or read only memory, or any combination thereof. When processor  205  is a microprocessor, logic  215  and  220  can be processor executable code loaded from memory  210 . 
       FIG. 3  is a flow chart illustrating an exemplary method for dispatch call paging to multiple dispatch stations in accordance with the present invention. When dispatch call handler  200  receives a dispatch call request (step  302 ), logic  215  determines whether the dispatch station identifier included in the call request is associated with multiple dispatch stations (step  304 ). The association of multiple dispatch stations with a dispatch station identifier can be stored in call register  112  or another database (not illustrated). Each of the multiple dispatch stations can have a single dispatch station identifier, and each of the multiple dispatch stations can be associated with the other dispatch station identifiers. The association of dispatch station identifiers with dispatch stations can be performed via an interactive voice response system, a live-human operator, a web-based interface and/or the like. 
     When the dispatch station identifier in the dispatch call request is not associated with multiple dispatch stations (“No” path out of decision step  304 ), then the dispatch call is established in accordance with conventional procedures (step  306 ). When logic  215  determines that there are multiple dispatch stations associated with the dispatch station identifier (“Yes” path out of decision step  304 ), then logic  215  determines whether all of the dispatch stations are supported by the call handler (step  308 ). This determination can be based on the information previously obtained from the call register  112 , or a new request can be performed to obtain this information. 
     When all of the dispatch stations are supported by the dispatch call handler (“Yes” path out of decision step  308 ), then the dispatch call handler pages all associated dispatch stations (step  310 ) and waits for responses from one of the paged dispatch stations (step  312 ). Some dispatch communication systems provide two different types of one-to-one dispatch calls, dispatch call alerts and dispatch private calls. Dispatch call alerts merely notify the destination dispatch station of the incoming dispatch call, and the dispatch call is connected by the destination actuating the dispatch call button of the dispatch station. In contrast, a dispatch private call includes audio from the originator of the call that is automatically reproduced by the destination dispatch station (commonly referred to as “forced-audio”). Accordingly, when the incoming dispatch call is a dispatch private call, each of the associated dispatch stations will reproduce the audio from the originator until one of the associated dispatch stations responds to the page. 
     When the first dispatch station responds to the page, then logic  215  connects the responding dispatch station to the dispatch call and terminates paging of and providing forced-audio to the other dispatch stations (step  314 ). A dispatch station responds to the page by actuating a dispatch call button on the dispatch station. While the dispatch call button is depressed, an operator of the destination dispatch station can provide audio to the dispatch station, which is then delivered to the call initiator upon release of the button. 
     When at least one of the dispatch stations is supported by a different call handler (“No” path out of decision step  308 ), then logic  215  identifies the dispatch call handlers supporting the other dispatch stations (step  316 ). This determination can be based on the information previously obtained from the call register  112 , or a new request can be performed to obtain this information. The dispatch call handler then sends pages to the other identified dispatch call handlers (step  318 ) and waits for a response to the page (step  320 ). 
     When a response to the page is received (“Yes” path out of decision step  320 ), then logic  215  determines whether the page response is from a local dispatch station (step  322 ). When the page response is from a dispatch station supported by the call handler (“Yes” path out of decision step  322 ), then logic  215  controls the call handler to terminate the paging procedure with the other dispatch call handlers and establish the dispatch call with the responding dispatch station (step  324 ). When the page response is from a dispatch station supported by another dispatch call handler (“No” path out of decision step  322 ), then logic  215  controls the transfer of the dispatch call to the dispatch call handler supporting the responding dispatch station and terminates the paging process for all other dispatch stations (step  326 ). 
       FIG. 4  is a flow chart illustrating an exemplary method for managing multiple dispatch calls in accordance with the present invention. As used herein, a dispatch call includes a private dispatch call, a call alert, a group dispatch call, a dispatch chatroom call (e.g., an ad-hoc or closed chatroom), or the like. While a user is on a call (step  402 ), logic  220  determines whether the user initiates a second call (step  404 ). The user can initiate a dispatch call by selecting a soft key requesting that the active call be placed on-hold and by entering an address of another dispatch station, for example, by using an address book entry or by manually entering the address. 
     When the user has initiated a second call (“Yes” path out of decision step  404 ), then logic  220  places the current call on-hold (step  408 ) and initiates the second call (step  410 ). If conservation of radio resources is desired, signaling and media for the on-hold call is not transmitted over the radio access network to the dispatch station. If the dispatch call on-hold includes more than one additional dispatch station, the call will continue until there is no activity on the call. Specifically, logic  220  monitors the activity of the on-hold call to determine whether there has been any activity for a predetermined amount of time (step  412 ). When there has not been any activity on the on-hold call for the predetermined amount of time (“Yes” path out of decision step  412 ), then logic  220  instructs the dispatch call handler to drop the on-hold call (step  414 ). When there has been activity for the on-hold call within the predetermined amount of time (“No” path out of decision step  412 ), then logic  220  determines whether it has received a merge request (step  416 ). 
     When logic  220  receives a merge request (“Yes” path out of decision step  416 ), then logic  220  controls the dispatch call handler to join the active and on-hold dispatch calls into a single dispatch call (step  418 ). When logic  220  has not received a merge request (“No” path out of decision step  416 ), then logic  220  determines whether the active call has ended (step  420 ). When the active call has ended (“Yes” path out of decision step  420 ), then logic  220  controls the dispatch call handler to switch the on-hold call to the dispatch station (step  422 ). Instead of automatically switching to the on-hold call (step  422 ), the dispatch station can provide the user with the option of returning to the on-hold call or dropping the on-hold call. When the active call has not ended (“No” path out of decision step  420 ), then logic  220  continues to monitor the activity of the on-hold call (step  412 ). 
     When the user has not initiated a second call (“No” path out of decision step  404 ), logic  220  determines whether the user has received a second dispatch call (step  424 ). When the user receives a second dispatch call, the user will be alerted by an audible tone and/or a user interface message. Moreover, the caller can receive a distinct audible tone notifying him that the called party is on a call. When the user has not received a second dispatch call (“No” path out of decision step  424 ), then logic  220  determines whether the user has initiated a second call (step  404 ). Although not illustrated in  FIG. 4 , if the call ends and the user has not initiated a second call or received a second call, then the processing terminates. 
     When the user receives a second dispatch call (“Yes” path out of decision step  424 ), then logic  220  determines whether it has received an indication from the user that the user desires to connect to the second call (step  426 ). The user can select the second call using, for example, a soft key. When, after a predetermined amount of time, the user does not select the second call (“No” path out of decision step  426 ), then the second call is dropped (step  428 ). Alternatively, the user of the dispatch station can arrange to have the second call sent to voice mail. When the user selects the second call (“Yes” path out of decision step  426 ), then the current call is placed on-hold (step  430 ) and the second call is activated (step  432 ). The management of the second call and the on-hold call then proceeds as discussed above in connection with steps  412 - 422 . 
     Although the method of  FIG. 4  is described as involving two dispatch calls, the method is equally applicable to one dispatch call and one interconnect call. In this case, the dispatch call handler will coordinate with a corresponding network element of the interconnect communication system. Moreover, a dispatch station can freely switch between the active and on-hold calls using, for example, a soft key of the dispatch station. The user of the dispatch station can enable and disable the ability to receive notifications of incoming calls while active on a call. In the method of  FIG. 4 , audio from the on-hold call can be combined with audio from the active call, where audio from the on-hold is attenuated to a lower level than the active call. This allows the user of the dispatch station to continue to monitor the activity of the on-hold call. 
     The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.