Abstract:
An integrated IP-SS7 gateway and home location register system is disclosed for transmitting and receiving messages in a wireless communication network. The system comprises a processing system including a home location register (HLR) storing wireless user subscriber information. A first interface is in communication with a wireless office system (WOS) network for routing messages using a TCP/IP protocol. A second interface is in communication with a public land mobile network (PLMN) for routing messages using an MTP protocol. A gateway function is operatively connected to the HLR and the first and second interfaces for controlling message transmission therebetween.

Description:
FIELD OF THE INVENTION 
     This invention relates to wireless office communication systems and, more particularly, to an integrated IP-SS7 gateway and home location register. 
     BACKGROUND OF THE INVENTION 
     A wireless communication system, in the form of a cellular system, is designed to cover a large geographic area. The system is divided into numerous cells providing air interface between mobile stations and land-based systems. The network interfaces described herein are based on the ANSI-41 intersystem communications standard. This standard defines the functionality for a Mobile Application Part (MAP) for personal communication systems (PCS). Messages are sent via signaling system 7 (SS7) protocols. 
     Recently, cellular based system design is being used as a foundation for smaller systems, such as a wireless office system (WOS). One such WOS employs time-division multiple access (TDMA) technology to deliver a private communication environment that is flexible and compatible with existing digital wireless networks. 
     A TDMA WOS may be associated with a TDMA PLMN and requires a way to transmit and receive ANSI-41 messages. These messages are normally sent via SS7 protocols and routed using either direct point code (PC) routing or global title translation (GTT). 
     One design of a WOS contemplates connecting to the SS7 network through use of a WOS gateway. The gateway is a separate physical node serving one or more WOSs. From the perspective of the SS7 network, the WOS is a signaling point (SP) with its own point code. However, this system adds an additional physical node to the network architecture, which results in more equipment in the network and a larger number of nodes to configure. This design requires that any purchaser of the WOS also has access to this gateway node, or provide the same functionality separately. 
     The vast majority of the messages that the gateway passes between the WOS and the SS7 network are for a home location register (HLR) which stores wireless user subscriber information. In order to communicate with the HLR, the gateway must process the messages and perform a protocol conversion. This increases processing and delays in operation of the WOS. 
     The present invention is directed to overcoming one or more of the problems discussed above in a novel and simple manner. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention there is provided an integrated home location register and wireless office system gateway. 
     Broadly, there is disclosed herein a router controlling message communication between a first wireless communication network that transmits and receives messages using a TCP/IP protocol and a second wireless communication network that transmits and receives messages using an MTP protocol. The router includes an integrated processing system including a home location register (HLR) storing wireless user subscriber information. A first interface communicates with the first wireless communication network using the TCP/IP protocol. A second interface communicates with the second wireless communication network using the MTP protocol. A gateway function is operatively connected to the HLR and the first and second interfaces for controlling message transmission therebetween. 
     It is a feature of the invention that the HLR stores subscriber information for users of both the first wireless communication network and the second wireless communication network. The gateway function transmits and receives HLR subscriber information with either network directly without protocol conversion. 
     It is another feature of the invention that the gateway function converts protocol of messages between TCP/IP and MTP for messages to be transferred from one of the networks to the other of the networks. The gateway function translates global titles received from the second wireless communication network to IP addresses for the first wireless communication network. 
     It is another feature of the invention that the gateway function operates as a signaling transfer point for the second wireless communication network via the second interface. 
     It is still a further feature of the invention that the gateway function operates as a termination point for first wireless communication network protocols. The first wireless communication network protocols may support monitoring of communication between the first wireless communication network and the gateway function or transport of configuration messages. 
     There is disclosed in accordance with another aspect of the invention an integrated gateway and home location register system for transmitting and receiving messages in a wireless communication network. The system comprises a processing system including a home location register (HLR) storing wireless user subscriber information. A first interface is in communication with a wireless office system (WOS) network for routing messages using a TCP/IP protocol. A second interface is in communication with a public land mobile network (PLMN) for routing messages using an MTP protocol. A gateway function is operatively connected to the HLR and the first and second interfaces for controlling message transmission therebetween. 
     More particularly, the present invention relates to combining gateway functionality of a WOS into an HLR. This system directly sends ANSI-41 messages from the WOS to the HLR using TCP/IP protocol. Additionally, since the HLR maintains SS7 routing information for the network, it is adapted to perform protocol conversion and routing functionality of the gateway without the need of an additional node. 
     Further features and advantages of the invention will be readily apparent from the specification and from the drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a network block diagram illustrating a prior art wireless office system associated with a public land mobile network; 
     FIG. 2 is a layer diagram illustrating protocol stacks for the system of FIG. 1; 
     FIG. 3 is a network block diagram illustrating a wireless office system associated with a public land mobile network according to the invention; and 
     FIG. 4 is a layer diagram illustrating protocol stacks for the system of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a block diagram illustrates a time-division multiple access (TDMA) wireless office system (WOS)  10  associated with a TDMA public land mobile network (PLMN)  12 . The PLMN  12  may be of any desired configuration and is particularly adapted for transmitting and receiving messages using ANSI-41 standards. These messages are normally sent via signaling system 7 (SS7) protocol as illustrated by the network “cloud”  13 . In the illustrated embodiment of the invention, the PLMN  12  includes plural nodes. These nodes include a mobile switching center (MSC)  14 , a home location register (HLR)  16  and an MC block  18  representing multiple carriers. 
     The WOS system  10  includes plural WOS blocks  20 , two of which are illustrated. The WOS  20 , in accordance with the invention, may take any desired form. For example, the WOS  20  may include a private branch exchange (PBX) as a switching center to receive calls from, and send calls to, the public switched telephone network (PSTN). The PBX may in turn be connected to a hub which controls and coordinates wireless connection among a plurality of fixed radio heads and various wireless devices, such as a mobile station  22 . The mobile station  22  can also be configured to directly communicate in the PLMN  12 . The WOS system  10  is adapted to operate as a reduced scale version of the PLMN  12  in controlling communication with the mobile station  22 . For example, the system  10  is used to initiate service with the mobile station  22  and provide handoffs and the like as the mobile station moves within the WOS system  10 . 
     To enhance operations, one such WOS system  10  connects to the PLMN  12  through the use of a WOS gateway  22 . The gateway  24  is a separate physical node serving one or more WOSs  20 . From the PLMN network  12  point of view, the gateway  24  is a signaling point (SP) with its own point code (PC). The gateway  24  and WOS blocks  20  communicate via a network  26  using Internet protocol (IP). 
     Referring to FIG. 2, the WOS system  10  uses the SCCP, TCAP, and MAP layers of the SS7 protocol stack on top of a TCP/IP protocol stack to transport ANSI-41 messages to the gateway  24 . The gateway  24  converts the messages from riding atop the TCP/IP protocol stack to riding on the MTP layers of the SS7 protocol stack. Particularly, the gateway  24  acts as a router in that it is a signaling transfer point (STP) in the SS7 protocol, and performs GTT for messages from the WOS system  10 . This frees the WOS  20  from having to maintain point code tables. The reformatted message is then sent on to its final destination from the gateway  24 . The gateway  24  also receives SS7 messages meant for the WOS system  10  and determines which WOS  20  is being addressed if necessary, and repacks the messages onto TCP/IP for delivery to the particular WOS  20 . 
     The illustrated gateway  24  adds an additional physical node to the network architecture. This results in more equipment in the network and a larger number of nodes to configure. It also requires that a purchaser of the WOS system  10  has access to this node, or provides the same capability separately. The vast majority of messages in the WOS system  10  are to the associated HLR  16 . These messages provide subscriber information used for controlling communication with the mobile station  22 . 
     In accordance with the invention, the HLR is integrated with a WOS gateway so that for HLR messages protocol conversions are unnecessary. 
     Referring to FIG. 3, a block diagram illustrates an improved system in which an HLR is integrated with a gateway, as represented by the HLR-GW block  30 . Particularly, in accordance with the invention, the WOS gateway functionality is combined with an HLR in a single node. This functionality consists of software applications implemented on an integrated processing system in the form of a network server. Referring also to FIG. 4, the HLR-GW  30  includes a home location register (HLR)  32  and a WOS gateway  34 . The HLR function  32  stores wireless user subscriber information for use both by the WOS system  10  and the PLMN  12 . With the combined functionality ANSI-41 messages from the WOS system  10  are sent directly to the HLR  32  using TCP/IP protocols. Thus, the integrated HLR-GW  30  eliminates one or more physical nodes from prior systems. 
     As above, the WOS  20  uses the SCCP, TCAP and MAP layers of the SS7 protocol stack on top of the TCP/IP stack to transfer the messages to the HLR-GW  30 . A WOSP stack is included between the SCCP stack and the TCP stack for addressing at both ends. The HLR-GW  30  uses the SCCP, TCAP and MAP layers of the SS7 protocol on top of the TCP/IP stack for connection to the IP network  26  and on top of an MTP layer for connection to the SS7 network  13 . 
     The HLR  32  maintains SS7 routing information for the PLMN  12  and the WOS-GW  34  performs the protocol conversions and routing functionality of the prior gateway without the need of additional gateway nodes being configured with routing information. 
     The HLR-GW  30  has three main responsibilities. These responsibilities are the PLMN HLR, routing between SS7 nodes and the IP network  26 , and WOS protocol termination. 
     The HLR function  32  serves the normal role as an HLR in the PLMN  12 . The HLR  32  serves both subscribers using WOSs  20  and subscribers not using WOSs. From the PLMN  12  the HLR  32  is reached in the standard manner through the SS7 network  13 . From the WOS  20 , the HLR  32  is reached directly via the IP network  26  without any protocol conversions. Because the majority of messages between a WOS  20  and PLMN  12  are with the associated HLR, for those messages unnecessary processing and delays because of protocol conversion are avoided. 
     The HLR-GW  30  acts as an SS7 signaling transfer point (STP) with the interworking function between the SS7 MTP and TCP/IP. If global title (GT) is used to address the WOS  20 , a translation between the GT and the associated IP address is done by the HLR/GW  30 . 
     The WOS-GW  34  terminates WOS protocols. The WOS protocols may, for example, support monitoring of the connection between the WOS  20  and gateway  34 , and transport of configuration messages. Administration of configuration information to be sent from the PLMN to the WOSs  20  is made through the HLR-GW  30 . Thus, no extra nodes, in the form of separate gateways, have to be reached from the operation support system. 
     As described, the HLR-GW is an integrated software application running on a server. As is apparent, the HLR function  32  and the gateway function  34  could be separate software applications, running on one or more servers, withe the software applications interacting via a suitable network connection. In any event the HLR-GW  30  is configured to be a single node with respect both to the SS7 network  13  and the IP network  26 . 
     Thus, in accordance with the invention, the wireless office gateway functionality is integrated with an HLR in a single node for both an SS7 network and an IP network.