Abstract:
There is disclosed an inbound message receiving system for use in a wireless messaging system. The inbound message receiving system comprises: 1) a source base transceiver station capable of receiving a wireless message from a source mobile station disposed in a coverage area of the base transceiver station; and 2) a first satellite transceiver coupled to the base transceiver station and capable of transmitting the wireless message to a satellite. The use of a satellite uplink that is closely associated with the base transceiver station allows all wireless messages to be relayed directly to a central message processor without requiring the wireless messages to be transported via long-distance lines or other toll-charge bearing communication lines.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention is directed, in general, to wireless communication systems and methods of operating the same and, in particular, to a wireless communications system that reduces or eliminates long distance links that are subject to toll charges. 
     BACKGROUND OF THE INVENTION 
     The demand for better and cheaper wireless telecommunication services and equipment continues to grow at a rapid pace. Part of this demand includes wireless message paging devices, which have become ubiquitous in society. Traditional one-way message paging devices (or “beepers”) are giving way to newer two-way message paging devices. Additionally, the types of messages that may be send to a beeper have expanded from short telephone number messages to longer length alphanumeric messages and even to voice messages. In some systems, wireless messages may comprise an alphanumeric or voice message to which an electronic file, such as a text document, may be attached. 
     Much of this growth resulted from the Federal Communication Commission&#39;s (“FCC”) approval of certain frequency bands for the next generation of Personal Communication Service (“PCS”) devices that provide voice telephone service as well as advanced voice and/or data message paging services. A relatively small portion of the available spectrum was set aside for narrowband PCS, which is more suited to advanced message paging services, to encourage efficient use of the available spectrum. 
     The infrastructure of message paging systems includes a substantial amount of wired backbone that interconnects base transceiver stations to a central hub that routes wireless messages to final destinations. For example, a group of base transceiver stations operated by a wireless messaging service provider in New York City may be wired by local network connections to a regional terminal owned by the wireless messaging service provider and located in the New York City area. The regional terminals may then be linked to a central terminal (“hub”) in some other location (e.g., Chicago or Atlanta) by means of long distance lines. The central hub contains databases that may be used to direct wireless messages to target devices around the country. 
     From the central hub, the wireless messages are transmitted on an uplink to a satellite and are re-transmitted on a downlink to base transceiver stations across the country. Thus, a two-way pager may send a wireless message to a first base transceiver station in New York City and the wireless message may be sent via satellite to a second base transceiver station in Miami, where it is re-transmitted locally to a target wireless messaging device. 
     One significant drawback to the above-described architecture is the requirement for a large amount of network interface equipment that connects the hundreds or even thousands of base transceiver stations to the long-distance networks. This significantly increases the costs associated with building the wireless network infrastructure. 
     Another significant drawback is its reliance on long-distance lines to carry wireless message traffic to the central hub. Since all, or nearly all, wireless messages are transported by long-distance lines, long-distance charges (or tolls) make up a significant portion of the operating costs of the wireless messaging network. This results in higher monthly service fees to subscribers of the wireless service provider. 
     Wireless message devices that are “roaming” are particularly susceptible to long-distance charges. In normal operations, a wireless message sent to a subscriber is directed to a message server in the “home” area in which the subscriber normally resides. However, when a subscriber turns on his pager in a remote (or “roaming”) area, the pager registers with a message server in the roaming area. The roaming area message server sends a notification to the subscriber&#39;s home area message server, which then re-directs all new messages that it receives to the roaming area message server. The roaming area message server then delivers the wireless messages by transmission from base transceiver stations in the roaming area. 
     Thus, if a source message pager sends a wireless message to a target message pager that is roaming in the same coverage area, the wireless message first must be sent to the home area of the target message pager and then must be re-directed to the coverage area in which both the source and target message pagers are located. This may result in long-distance toll charges in both directions. 
     Therefore, there exists a need in the art for an improved wireless messaging system that does not require a large amount of network interface equipment to connect base transceiver stations to long-distance networks. There exists a further need for a wireless messaging system that minimizes the number of toll charges incurred by using long-distance lines in the delivery of wireless messages. 
     SUMMARY OF THE INVENTION 
     The limitations inherent in the prior art described above are overcome by means of an inbound message receiving system for use in a wireless messaging system. The inbound message receiving system comprises: 1) a source base transceiver station capable of receiving a wireless message from a source mobile station disposed in a coverage area of the base transceiver station; and 2) a first satellite transceiver coupled to the base transceiver station and capable of transmitting the wireless message to a satellite. 
     According to one embodiment of the present invention, the satellite is a geosynchronous satellite. Alternatively, the satellite may comprise one or more of the following: low-earth orbit satellite(s), plane(s) flying at high altitude above a defined coverage area, high-altitude balloon(s), high-altitude blimp(s), and the like. 
     According to another embodiment of the present invention, the inbound message receiving system further comprises a second satellite transceiver capable of receiving from the satellite the wireless message. 
     According to still another embodiment of the present invention, the inbound message receiving system further comprises a message server coupled to the second satellite transceiver and capable of processing the wireless message and determining therefrom at least one target base transceiver station associated with a target mobile station to which the wireless message is directed. 
     According to yet another embodiment of the present invention, the mobile station is an alphanumeric paging device. 
     According to a further embodiment of the present invention, the mobile station is a telemetry device capable of two-way paging. 
     According to a still further embodiment of the present invention, the inbound message receiving system further comprises a local communication link for coupling the source base transceiver station to the first satellite transceiver and transferring the wireless message, wherein the local communication link does not include a portion that is part of a long-distance network subject to long-distance fees. 
     The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form. 
     Before undertaking the DETAILED DESCRIPTION, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, wherein like numbers designate like objects and in which: 
     FIG. 1 illustrates an exemplary wireless network according to one embodiment of the present invention; 
     FIG. 2 illustrates central server according to one embodiment of the present invention; and 
     FIG. 3 is a flow diagram illustrating the operation of the exemplary wireless network in FIG. 1 according to one embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     FIGS. 1 through 3, discussed below, and the various embodiments used to describe the principles of the present invention in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the invention. Those skilled in the art will understand that the principles of the present invention may be implemented in any suitably arranged wireless messaging network. 
     FIG. 1 illustrates an exemplary wireless messaging network  100  according to one embodiment of the present invention. Wireless messaging network  100  comprises groups of base transceiver stations, groups of satellite transceiver stations, and a wireless messaging hub that form a nationwide infrastructure used by a wireless messaging service provider. The base transceiver stations receive wireless messages and relay them to the wireless messaging hub by means of the satellite transceiver stations, thereby eliminating the need for long-distance wireline connections. 
     Base transceiver station  101  and base transceiver station  102  operate in regional service area  110 , which may be, for example, Seattle, Wash. Base transceiver stations  101  and  102  are coupled to common satellite transceiver  105  via wireline  106 . In an advantageous embodiment of the present invention, wireline  106  is a local network or local telephone line, so that wireless messages received by base transceiver station  101  and base transceiver station  102  may be relayed to satellite transceiver  105  without using long distance lines. 
     Although base transceiver station  101  and base transceiver station  102  are shown sharing satellite transceiver  105 , in an advantageous embodiment of the present invention, base transceiver station  101  and base transceiver station  102  each may be coupled to individual satellite transceivers located at the base transceiver station. In such an embodiment, wireline  106  may be eliminated. 
     Base transceiver stations  111  and base transceiver station  112  operate in regional service area  120 , which may be, for example, New York City. Base transceiver stations  111  and  112  are coupled to common satellite transceiver  115  via wireline  116 . As before, in an advantageous embodiment of the present invention, wireline  116  is a local network or local telephone line, so that wireless messages received by base transceiver station  111  and base transceiver station  112  may be relayed to satellite transceiver  115  without using long distance lines. 
     Although base transceiver station  111  and base transceiver station  112  are shown sharing satellite transceiver  115 , in an advantageous embodiment of the present invention, base transceiver station  111  and base transceiver station  112  each may be coupled to individual satellite transceivers located at the base transceiver station. In such an embodiment, wireline  116  may be eliminated. Additionally, in an advantageous embodiment of the present invention, base transceiver stations  111  and  112  each may be coupled to separate satellite transceivers or to a common satellite transceiver by means of a wireless link, such as a spread spectrum radio link or the like. 
     Satellite transceiver  105  receives wireless messages from base transceiver stations  101  and  102  and transmits the wireless messages according to an established protocol to satellite  160 . Each of base transceiver stations  101  and  102  receive wireless messages from mobile stations  121 ,  122  and  123 . Base transceiver stations  101  and  102  also transmit wireless messages to mobile stations  121 ,  122  and  123 . 
     Similarly, satellite transceiver  115  receives wireless messages from base transceiver stations  111  and  112  and transmits the wireless messages according to an established protocol to satellite  160 . Each of base transceiver stations  111  and  112  receive wireless messages from mobile stations  131 ,  132  and  133 . Base transceiver stations  111  and  112  also transmit wireless messages to mobile stations  131 ,  132  and  133 . 
     Mobile stations  121 - 123  and mobile stations  131 - 133  comprise a wide variety of two-way wireless messaging devices. For example, one or more of mobile stations  121 - 123  and mobile stations  131 - 133  may comprise a two-way text message pager carried by subscriber or a two-way paging terminal embedded in another electronic apparatus, such a personal computer (PC) or a hand-held personal digital assistant (PDA) device, such as a PALMPILOT™ device. In another embodiment, one or more of mobile stations  121 - 123  and mobile stations  131 - 133  may comprise a telemetry paging device used to transfer data measured or recorded in different types of remotely disposed equipment, such as vending machines, vehicles, oil wells, pipelines, etc. In still another embodiment of the present invention, one or more of mobile stations  121 - 123  and mobile stations  131 - 133  may comprise a personal communications services (PCS) device capable of sending and receiving alphanumeric text messages and/or relatively short voice messages. In general, the content of the wireless messages could be any binary encoded content, including e-mail, documents, graphics, voice, video, or the like. 
     Central server  150  is the message routing hub for all of wireless messaging network  100 . Any wireless message transmitted by one of mobile stations  121 - 123  in regional service area  110  is received in a “reverse” channel by one of base transceiver stations  101  or  102  and is relayed by satellite transceiver  105  to satellite  160 . Similarly, any wireless message transmitted by one of mobile stations  131 - 133  in regional service area  120  is received in a “reverse” channel by one of base transceiver stations  111  or  112  and is relayed by satellite transceiver  115  to satellite  160 . 
     Satellite  160  retransmits the wireless messages received from satellite transceivers  105  and  115  to satellite transceiver  140  on the ground. If central server  150  is located remotely from satellite transceiver  140 , satellite transceiver  140  may be coupled to central server  150  via wireline  145 . As will be explained below in greater detail, central server  150  receives and sorts incoming wireless messages from satellite  160  and groups together wireless messages that are being sent to target mobile stations located in the same regional service area. Central server  150  then retransmits the reformatted packets of wireless messages back to satellite  160  via satellite transceiver  140 . Next, satellite  160  transmits the packets of wireless messages to the base transceiver stations in the target regional service area. Finally, the base transceiver stations in the target service area transmit the wireless messages in a “forward” channel to the mobile stations in the target regional service area. 
     Not all messages handled by wireless messaging network  100  originate from a wireless device. Many messages will originate from wireline devices, such as numeric telephone pages or e-mail transmitted from a PC. To accommodate these messages, wireless messaging network  100  contains numerous interfaces to the central office exchanges of the public switched telephone network (PSTN) and to the public Internet. 
     For example, in regional service area  110 , locally generated wireless messages are received from PSTN interface  125  and in regional service area  120 , locally generated wireless messages are received from PSTN interface  135 . The messages received from PSTN interfaces  125  and  135  then may be transmitted via satellite transceivers  105  and  115  to satellite transceiver  140  and central server  150  without using long-distance lines. Furthermore, central server  150  may also receive messages directly from PSTN interface  155 . 
     To facilitate the handling of locally generated wireless messages received from PSTN interfaces  125  and  135 , regional service areas  110  and  120  may further comprise interactive voice response interface (IVR IF)  126  and interactive voice response interface (IVR IF)  136 , respectively. A caller who wishes to send a numeric message, an alphanumeric message, or a voice message to a subscriber calls into an interactive voice response interface in the caller&#39;s local area and interacts with the interactive voice response interface by means of a series of voice message prompts, DTMF key pad entries, spoken responses, etc. 
     For example, if mobile station (MS)  131  is a message paging unit and a caller in regional service area  110  dials the subscriber telephone number corresponding to MS  131 , the caller is automatically connected to IVR IF  126 , which may play to the caller a system voice greeting message, or a voice greeting message recorded by the subscriber. The voice greeting message typically prompts the caller to enter the caller&#39;s telephone number using the telephone keypad. IVR IF  126  then stores the caller&#39;s telephone number and formats it in a wireless message that is suitable for transmission to central server  150  via satellite  160 , as described below in greater detail. 
     Alternatively, the caller may be prompted to leave a voice message by IVR IF  126 , which records the caller&#39;s voice. IVR IF  126  may then send a short message to the subscriber indicating that the subscriber has received a voice message. The subscriber then has the option of calling into IVR IF  126  to retrieve the stored voice message. IVR IF  126  also may use any one of a number of well-known voice compression algorithms to convert the caller&#39;s stored voice message to digital data that may be incorporated into one or more wireless messages that are suitable for transmission to central server  150 . 
     In still other embodiments of the present invention, IVR IF  126  may comprise modems devices that enable IVR IF  126  to interact with a processing device, such as a personal computer, in order to receive and reformat alphanumeric messages, such as e-mail, graphics files, video files, audio files, or the like. These files/messages may then be transmitted to central server  150 . In sum, IVR IF  126 , IVR IF  136  and other regionally located interactive voice response interfaces enable wireless messaging network  100  to receive data messages in a variety of different formats from the public switched telephone network over local lines in the different regional service areas. These data messages are then re-formatted for transmission to central server  150  and, ultimately, delivery to the wireless messaging unit of the targeted subscriber. 
     The operation of wireless messaging network  100  may be better understood by means of illustrative example. A subscriber originates a wireless message using mobile station  121 , which is a two-way numeric pager. The wireless message is to be sent to mobile station  131 , which also is a two-way numeric pager. The wireless message is received in a reverse channel by base transceiver station  101  and is sent to satellite transceiver  105 . Satellite transceiver  105  transmits the wireless message (and other messages perhaps) on an uplink connection to satellite  160 . Satellite  160  relays the wireless message(s) on a downlink connection to satellite transceiver  140 . Satellite transceiver  140  then transfers the wireless message(s) to central server  150 . 
     Central server  150  then determines that the target mobile station  131  is located in regional service area  120 . Central server  150  then adds the wireless message to a larger frame of wireless messages destined for regional service area  120  and sends the message frame to satellite transceiver  140 . Satellite transceiver  140  then transmits the frame to satellite  160 , which re-transmits the frame to satellite transceiver  115 . The wireless message is then broadcast in a forward channel by base transceiver stations  111  and  112  and is received by mobile station  131 . 
     In the above-described embodiment of the present invention, satellite  160  gathers all “inbound” wireless messages from all base transceiver stations and sends them to central server  150 . Satellite  160  also receives all “outbound” messages from central server  150  and distributes them to the base transceiver stations. However, this is by way of illustration only, and it will be understood by those skilled in the art that more than one satellite may be used to operate wireless messaging network  100 . For example, perhaps one or more other satellites may be used to gather the inbound wireless messages from all of the source base transceiver stations, while one or more other satellites may be used to distribute the outbound wireless messages to the destination base transceiver stations. 
     In an advantageous embodiment of the present invention, satellite  160  (and any other satellite used by wireless messaging network  100 ) is in a geosynchronous orbit, such that satellite  160  is located at a fixed point in the sky with respect to the satellite transceivers  105 ,  115 , and  140 . In alternate embodiments of the present invention, satellite  160  may comprise combinations of any one or more of the following: low-earth orbit satellite(s), plane(s) flying at high altitude above a defined coverage area, high-altitude balloon(s) or blimp(s), and the like. In sum, the term “satellite” in this disclosure may include any type of airborne system that can wirelessly relay messages across comparatively large distances to and from central server  150 . 
     Satellite transceivers  105 ,  115 , and  140  may communicate with satellite  160  by means of any conventional protocol, such as frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), or the like. Similarly, base transceiver stations  101 ,  102 ,  111 , and  112  may communicate with mobile stations  121 - 123  and  131 - 133  by means of one or more conventional protocols, such as frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), or the like. In an advantageous embodiment of the present invention, mobile stations  121 - 123  and  131 - 133  and base transceiver stations  101 ,  102 ,  111 , and  112  communicate using a TDMA protocol in the narrowband PCS spectrum, such as REFLEX25™ protocol developed by Motorola, Inc. 
     FIG. 2 illustrates central server  150  according to one embodiment of the present invention. Central server  150  comprises message processor  205 , memory  210 , satellite uplink interface  220 , satellite downlink interface  230 , and data bus  240 . Memory  210  contains the operating program executed by message processor  205  and a plurality of data structures, including inbound queues  211 , outbound queues  212  and target look-up table  213 . 
     Wireless messages are received from satellite transceiver  140  by satellite downlink interface  230  and are stored in memory  210  in inbound queues  211 . Message processor  205  parses each of the wireless messages in inbound queues  211  and examines the destination address in each message header to determine the target mobile station to the wireless message is directed. Message processor  205  uses the address of the target mobile station to search target look-up table  213  in order to determine the target regional service area in which the target mobile station is currently located. Message processor  205  also identifies the base transceiver station(s) in the target regional service area. 
     All wireless messages that are being sent to mobile stations in the same target regional service area are then packed together in the same larger transmission frame in outbound queues  212 . Message processor attaches to each such transmission frame address and header information fields that enable the base transceiver stations in the target regional service areas to identify wireless messages that are being sent to them. The transmission frames in the outbound queues  212  are then sent to satellite uplink interface  220 , which transfers the transmission frames to satellite transceiver  140  for subsequent transmission to satellite  160 . 
     FIG. 3 is a flow diagram  300  illustrating the operation of the exemplary wireless network  100  according to one embodiment of the present invention. Flow diagram  300  outlines the processing of a wireless message from source mobile station  121  to target mobile station  131 . Initially, a wireless message is received in the reverse channel from source mobile station  121  by base transceiver station  101  (process step  301 ). The received wireless message (and possibly other messages) are sent to satellite transceiver  105  associated with base transceiver station  101  (process step  302 ). Satellite transceiver  105  transmits the wireless message(s) in a larger transmission frame to satellite  160 , including wireless messages from other base transceiver stations, if any, served by satellite transceiver  105  (process step  303 ). 
     Next, satellite  160  relays the received transmission frame to satellite transceiver  140  associated with central server  150  (process step  304 ). Central server  150  processes the wireless messages in the received transmission frame and transfers to satellite transceiver  140  outbound transmission frames containing reformatted wireless messages (process step  305 ). Satellite transceiver  140  then transmits the outbound wireless messages to satellite  160  (process step  306 ). 
     Satellite  160  relays the received outbound wireless messages to satellite transceiver  115 , which is associated with target base transceiver station  111  and target base transceiver station  112  (process step  307 ). Target base transceiver station  111  and target base transceiver station  112  then simultaneously broadcast (i.e., simulcast) the original wireless message to target mobile station  131  (process step  308 ). 
     Although the principles of the present invention have been described in detail with reference to message paging system and infrastructure embodiments, those of ordinary skill in the art should understand that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the invention in its broadest form.