Patent Document

BACKGROUND OF THE INVENTION 
     Doctors and other medical personnel have typically been early adopters of various forms of wireless communication technology such as wireless pagers and wireless telephones. In the medical and other industries Vocera Communications provides an in-building wireless local area network (LAN) voice communication network that employs communication badges worn by users. The communication badges include a button for initiating a connection to a voice communications server. The user of the communication badge can then speak a command into the badge and the voice communications server recognizes the voice command and acts upon it accordingly. For more information on the system provided by Vocera Communications the interested reader should refer to U.S. Pat. Nos. 6,892,033 and 6,901,255. 
     SUMMARY OF THE INVENTION 
     Although the system by Vocera Communications allows calls to and from the public switched telephone network (PSTN), these calls are limited to conventional circuit-switched calls. Exemplary embodiments of the present invention allow in-building wireless LAN voice communications to be conducted with push-to-talk communication units supported by a wide area network (WAN). Moreover, exemplary embodiments allow the in-building wireless LAN voice communications network to obtain presence information about push-to-talk communication units supported by a wide area network (WAN). 
     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 
         FIG. 1  is a block diagram of an exemplary system in accordance with the present invention; 
         FIG. 2  is a call flow diagram of an exemplary method of registration in accordance with the present invention; and 
         FIG. 3  is a flow diagram of an exemplary method of connecting calls between communication units supported by a local area network and a wide area network in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a block diagram of an exemplary system in accordance with the present invention. The system of  FIG. 1  allows wireless communication unit  104  and wired communication unit  106  of local area network (LAN)  102  to communicate with communication unit  124  supported by wide area network (WAN)  150 . Accordingly, communication unit  104  is coupled by a wireless communication link to an antenna and/or base station  109 , which in turn is coupled to a voice activated communication server (VACS)  110 . VACS  110  includes processor  110   a , and can include functionality of, for example, a Vocera Communication Server that runs Vocera Telephony Solution software. However, as will be described in more detail below, processor  110   a  includes additional functionality beyond that of the conventional Vocera Communication Server to allow calls between communication units of LAN  102  with push-to-talk communication units of WAN  150 . Specifically, processor  110   a  includes logic for implementing this additional functionality. Processor  110   a  can be any type of processor, such as a microprocessor, field programmable gate array (FPGA) and/or an application specific integrated circuit (ASIC), and when processor  110   a  is a microprocessor then the logic can be processor-executable code loaded from memory  110   b.    
     Wireless antenna and/or wireless base station  109  can use a wireless or wired communication link as a backhaul to VACS  110 . The wireless communication link between LAN communication unit  104  and the wireless antenna and/or wireless base station  109  can be any type of wireless protocol, such as Bluetooth or 802.11. Wired LAN communication unit  106  is coupled to gateway  118  via network  190 . Gateway  118  can convert voice and data from a format of WAN  150  into a format of LAN  102  (e.g., a format employed by VACS  110 ), and vice versa. Wired LAN communication unit  106  can be, for example, a desktop computer running a push-to-talk application or a dedicated push-to-talk console. 
     For push-to-talk communications between communication unit  104  and communication unit  124 , VACS  110  is coupled to call control element  122  of the wide area network by way of proxy server  112 , gateway  118  and network  190 . Specifically, proxy server  112  includes a processor  112   b  coupling a VACS interface  112   a  to a PTT interface  112   c . Gateway  118  is also coupled to presence server  120 . Presence server  120  stores presence information for communication units of WAN  150  and LAN  102 . Processor  112   b  of proxy server  112  provides a call control signaling interface between VACS  110  and gateway  118 . Accordingly, processor  112   b  of proxy server  112  maps the call control protocol of the local area network  102  with that of WAN  150 . For example, when WAN  150  employs Push-to-Talk over Cellular (PoC) communication protocol, processor  112   b  of proxy server  112  can convert the protocol of local area network  102  into a PoC compatible protocol. If it is desired to support additional push-to-talk protocols, such as iDEN push-to-talk, gateway  118  can be coupled to an iDEN gateway (not illustrated), and gateway  118  can convert communication protocols from the PoC compatible protocol into the iDEN protocol. Alternatively, or additionally, the PoC to iDEN protocol conversion can be performed by gateway  118 . 
       FIG. 2  is a flow diagram of an exemplary method of registration for communication units  104 ,  106  and  124  in accordance with the present invention. LAN communication unit  104  or wired LAN communication unit  106  registers in a conventional manner by sending a registration request to VACS  110 / 110   a  (step  202 ), and if processor  110   a  determines that the communication unit is authorized, VACS  110 / 110   a  returns a registration confirmation message (step  204 ). 
     Unlike LAN communication unit  104  or wired LAN communication unit  106 , which is supported by the local area network and uses VACS  110  as its primary call control element, WAN communication unit  124  is supported by a wide area network and uses call control element  122 . In order to allow WAN communication unit  124  to communicate with LAN communication unit  104  or wired LAN communication unit  106 , when WAN communication unit  124  registers within the wide area network, a trigger causes communication unit  124  to send a registration request to gateway  118  via call control element  122  (step  206 ). This trigger can be sent across the wide area network or can be part of the processing of the communication unit itself. Alternatively, or additionally, call control element  122  or another element of the wide area network, can send the registration request to gateway  118 . WAN communication unit  124  can be arranged to allow a user to publish various types of presence statuses to presence server  120 . 
     Gateway  118  then sends an authorization request to presence server  120  (step  208 ), and presence server  120  responds with an authorization response (step  210 ). Gateway  118  then sends a registration request to proxy server  112  (step  212 ), and proxy server  112  sends a registration request to VACS  110 / 110   a  (step  214 ). Processor  110   a  of VACS  110  adds or updates a registration record for WAN communication unit  124  in its local database, and confirms the registration to proxy server  112  (step  216 ). Proxy server  112  confirms the registration request with gateway  118  (step  218 ). Gateway  118  then sends a registration confirmation message to WAN communication unit  124 /call control element  122  (step  220 ). Accordingly, when VACS  110 / 110   a  receives a call request that involves WAN communication unit  124 , processor  110   a  of VACS  110 , based on the registration information in its database, can request presence information from presence server  120 , and setup the call when WAN communication unit  124  is available. 
     It should be recognized that the particular messages described in connection with  FIG. 2  are merely exemplary, and could be any type of messages. For example, these messages can be session initiation protocol (SIP) messages, such as REGISTER, PUBLISH, SUBSCRIBE and NOTIFY messages. In this case, WAN communication unit  124  can include, for example, a Java client application that supports SIP messaging. 
       FIG. 3  is a flow diagram of an exemplary method for processor  110   a  of VACS  110  for connecting calls between communication units supported by a local area network and a wide area network in accordance with the present invention. When VACS  110  receives a call request from LAN communication unit  104  (step  302 ), processor  110   a  of VACS  110  determines whether at least one of the call recipients is located outside of the local area network  102  (step  304 ). The call request can be, for example, digitized voice with an identifier of a call recipient (e.g., a person and/or a group). Processor  110   a  of VACS  110  can determine whether the call recipient is located in local area network  102  by referencing a database of communication units currently registered with VACS  110 . When all of the call recipients are located inside of local area network  102  (“Yes” path out of decision step  304 ), then processor  110   a  of VACS  110  connects the call locally. 
     When at least one of the recipients of the call request is located outside of the local area network (“No” path out of decision step  304 ), then processor  110   a  of VACS  110  requests presence information from the wide area network (step  308 ). Specifically, processor  110   a  of VACS  110  obtains the presence information from presence server  120  by way of proxy server  112  and gateway  118 . When the presence information indicates that recipients of the call request that are located in the wide area network are all currently available (“Yes” path out of decision step  310 ), then processor  110   a  of VACS  110  coordinates the call with the wide area network (step  312 ). Specifically, VACS  110  communicates with proxy server  112 , gateway  118  and call control element  122  of the wide area network to setup the call. 
     When at least one of the recipients that is located on the wide area network is not available (“No” path out of decision step  310 ), then processor  110   a  of VACS  110  determines whether any of the recipients located on the wide area network are available. When at least one of the recipients located on the wide area network is available (“Yes” path out of decision step  314 ), then processor  110   a  of VACS  110  coordinates the call with the wide area network (step  316 ). The call requestor can be notified of the call recipients that are unavailable. When none of the recipients located on the wide area network are available (“No” path out of decision step  314 ), then processor  110   a  of VACS performs unavailability procedures, which can include notifying the call requestor that none of the recipients on the wide area network are available (step  318 ). 
     The use of presence information from a wide area network as described above has a number of advantages over conventional techniques for calls between communication units supported by wide area and local area networks. For example, if a group call included at least communication unit supported by the wide area network, presence information of the wide area network was not employed, and that communication unit was not available for the call (e.g., out of coverage, powered-off, on another call), then the communication units that were available may have to wait for the voice mail recording processing of the unavailable communication unit to be completed before conducting the call. Otherwise, the unavailable communication unit&#39;s voice mail system will record a portion of the 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.

Technology Category: h