Multiple wireless switching units embedded in a switching system

IS 2 170 212 T3

DESCRIPTION

Personal communication service systems.

Technical field

This invention relates to personal communication service systems, and specifically, to the insertion of a personal communication system in a telecommunication switching system.

Background of the invention

In the previous technique, it is known that a personal communication services system (PCS), also called a wireless system, can be connected to a terminal exchange (also called a local exchange) or a business telecommunication switching system (also called PBX) using what is called a line aspect connection. In a line-like connection, each wireless device that can be connected to the PCS system has a unique telephone number and telephone link in the switching system. The PCS system terminates each of these telephone links and answers a call received on a telephone link to connect that call to the wireless device assigned to that telephone link. When a wireless device originates a telephone call, the PCS system originates a call to the switching system on the telephone link assigned to the originating wireless device. The main advantage of the lone-like connection procedure is that all telephone functions are provided by existing commercial switching systems. In addition, the switching system provides the necessary billing and records of the telephonic rates associated with the calls originated by the wireless device.

The lone-like connection procedure has, however, a number of problems. For a small number of wireless devices, the lonely-looking connection procedure has the drawback that you need a separate PCS system that has a phosphor protection, power supplies, etc. As a consequence, for a small number of wireless devices, the lone-like connection procedure is very expensive. In addition, as the number of wireless devices increases, it is necessary to increase the switching capabilities of the PCS system so that an active wireless device can connect to its dedicated telephone link through the PCS system. This requires the PCS system to have a large capacity network for voice and data switching. Also, the lone-look connection procedure requires a link interface on the switching system side of a link and a link interface on the PCS system side of the link for each wireless handset. The result is that a great deal of money is spent on the link interfaces in both the switching system and the PCS system.

In EP-529359 a wireless switch is described which is used as an integral part of a telecommunication switching system to provide service to wireless telephones assigned according to the preamble of claim 1.

So what is needed is an inexpensive way to develop a PCS system using the lonely-looking connection procedure from a small number of wireless devices to a large number of wireless devices.

Summary of the invention

The foregoing problems have been solved, and a technical advance in the technique is achieved by inserting a PCS switch or a plurality of them into a switching system. PCS switches are both physically and logically integrated into the switching system. The switching system performs complex switching operations, which is a great advantage. Physically, each PCS switch emulates link interfaces in its connections to the data carriers and communication control of the switching system. Logically, each of the PCS switching units communicates with a control processor, controlling the operations of the switching system as if each of the PCS switches were a collection of individual stations. Each PCS switch is assigned a set of wireless devices. Each of the wireless devices has a unique telephone number that the switching system control processor identifies with a physical position in the communication medium.

When receiving an incoming call on a specific wireless device, the control processor directs the control and voice information of the call to the PCS switch that is emulating what appears to the control processor to be a station attached to the switching system. . If the wireless device registers to a base station attached to the assigned PCS switch, then the call is completed through the assigned PCS switch and the base station with the PCS switch directly handles communication between the wireless device and the control processor. . In addition, the PCS switch provides an internal network to connect the audio portion of the call between the base station and the communication medium of the switching system's switching network. If the wireless device registers with a base station connected to another PCS switch than the assigned PCS switch, the assigned PCS switch receives the call control information from the control processor and transmits this information to the other PCS switch. The assigned PCS switch then continued to transmit all the control information that was being exchanged between the control processor and the other PCS switches. The assigned PCS switch transmits the network connection information for the voice or circuit-switched data portion of the call to the other PCS switch. The other PCS switch responds to this network connection information to connect the wireless device through the es2.

ES 2 170 212 T3 base operation in the switching network of the switching system. Similar operations are carried out when a wireless device originates a call.

As additional wireless devices are added to the system, additional PCS switches are inserted into the switching system. Since the PCS switches transmit control information between them through the communication medium of the switching system, intercommunication between the PCS switches is physically provided. In addition, the data switching over circuits or voice is performed by the switching network of the switching system, and no additional switching capabilities are required from the PCS switches in place as the number of wireless devices increases. For a small number of wireless devices, only one PCS switch needs to be inserted into the switching system; therefore, there is no need for additional fossil protection, power supplies, etc. This means that the invention allows the number of wireless devices to increase from a small number to a very large number in an economical way.

These and other advantages and functions of the invention will be apparent from the following description of illustrative embodiments of the invention and the accompanying drawings.

Brief description of the drawings

Fig. 1 shows, in block diagram form, an embodiment of the invention;

Fig. 2 shows, in block diagram form, the internal structure of a switch

PCS;

Fig. 3 shows, in block diagram form, the software structure of a switching processor of a PCS switch;

Figures 4 and 5 show tables used by the switching processors of the PCS switches of Fig. 1;

Figures 6-9 show in greater detail the operations carried out by the switching processor.

Detailed description

Fig. 1 shows a first embodiment of the invention. The switching system 100 may be a terminal exchange or a business switching system. The 100 Switching System is the Definity® Business Switching System made by AT&T, which is a big plus. The switching system 100 consists of a control computer 101 that provides the maintenance, administration, and total control of the calls of the switching system 100. The network 102 has a plurality of TDM buses such as the TDM bus 103 ending in oel. However, Fig. 1 only shows TDM bus 103. Control computer 101 transmits and receives information on LAN bus 104. Switching system 100 is phosphically constructed using printed circuit board holders or carriers. Physically inserted into these printed circuit board carriers are printed circuit boards with BRI 107-109 link interfaces and PCS 111 and 112 switches as well as a control computer 101 and a network 102. Each PCS switch is placed on a single board. of printed circuits. There are 12 BRI interfaces on each printed circuit board. Using internally stored administrative tables, the control computer 101 associates a BRI station with a particular BRI link interface that is assigned to a physical location on a carrier. For example, if an external call is received for BRI station 106, the control computer 101 answers this incoming call to transmit a setup message through the LAN bus 104 to the BRI link interface 107 which transmits the message to the station. BRI station 106. Once the user of the BRI station 106 answers the call, the BRI station 106 transmits a connection message through the BRI link interface 107 and the LAN bus 104 to the control computer 101. The control computer 101 answers. with an acknowledgment message of the connection transmitted through the LAN bus 104 to the BRI link 107. The connection acknowledgment message specifies which of the two B-channels of the BRI link that interconnects the BRI link interface 107 and the BRI station 106 is to be used. In addition, the control computer 101 transmits through a control channel on the TDM BUS 103 the information of the slot that specifies to the link interface 107 the slot that will receive and transmit data by circuits or audio on the bus. TDM 103. The TDM bus 103 is a dual 256 slot parallel bus (for a total of 512 slots). The control channel is implemented in the first five slots of each frame on the TDM bus 103. The BRI link interface 107 responds to slot information to transmit and receive in the specified slot. The incoming call was received on another TDM bus that was interconnected via network 102 to TDM bus 103 by control computer 101. The switching system 100 can support a variety of links such as Primary Rate Interface (PRI) links or analog lines.

To understand the operation of a PCS switch, consider the following example. Assume that the phone number used by a wireless device 113 is assigned by a control computer 101 to a virtual BRI link interface emulated by the PCS switch 111. When BRI station 107 originates a call to wireless device 113, control computer 101 responds to the setup message received from BRI station 106 specifying the destination phone number to route the setup message through LAN bus 104 to the PCS 111 switch. If wireless device 113 registers through base station 114 to PCS switch 111, PCS switch 111 routes the setup message in a format acceptable to a wireless device to wireless device 113. When the user of the wireless device 113 answers the call from the BRI station 106, the wireless device 113 transmits a connection message to the PCS switch 111 through the base station 114 and the BRI link 123. The PCS switch 111 transmits this to him. connection message to control computer 101.

IS 2 170 212 T3

The control computer 101 transmits the setup message to the BRI station 106 via the LAN bus 104 and the BRI link interface 107. The connect message specifies to the BRI link interface 107 the B-channel that should be used. to transmit the information by voice to and from the BRI 106 station. In addition, the control computer 101 transmits through the control channel on the TDM bus 103 the slots that must be used by the BRI link interface 107 to receive information by audio or transmit information by audio on the TDM bus 103. Also, in In response to the connection message from the wireless device 113, the control computer 101 transmits back a connection acknowledgment message to the PCS switch 111. Also, the control computer 101 transmits the receive and transmit slot to the switch PCS111 through the TDM bus control channel 103. The PCS switch 111 uses this control information to establish a talk path from the wireless device 113 to the TDM bus 103. via base station 114, BRI link 123, and PCS switch 111.

Now consider an extension of this example. Assume that wireless device 113 registers to base station 119. Each PCS switch has an assignment table that defines the phone numbers of the wireless devices with respect to the assignment of these phone numbers to individual PCS switches. Fig. 5 shows such an allocation table. When the wireless device 113 registers with the base station 119, the PCS switch 112 looks at its allocation table and determines that the wireless device 113 is assigned to the PCS switch 111. The PCS switch 112 transmits a message over the LAN bus 104 to the PCS switch 111 indicating that the wireless device 113 is now registered to the PCS switch 112. If the BRI station 106 now requests a call to a wireless device 113 by transmitting a setup message, the control computer 101 responds to the setup message to route this message to the PCS switch 111. The PCS switch 111 determines from From its active table (Fig. 4) that station 113 is now registered in the PCS switch 112. The PCS switch 111 then transmits the setup message to the PCS switch 112 via the LAN bus 104. The PCS switch 112 responds to this setup message sent to transmit a setup message to the wireless device 113 through the base station 119. When the user of the wireless device 113 answers the call, the wireless device 113 transmits a connection message to the PCS switch 112 through the base station 119. The PCS switch 112 responds to this connection message to transmit the connection message. to the PCS switch 111 which transmits the connection message to the control computer 101. The control computer 101 responds to the connect message from the PCS switch 111 with a connection acknowledgment. Upon receiving the connection acknowledgment from the control computer 101, the PCS switch 111 transmits this connection acknowledgment message to the PCS switch 112. The control computer 101 also transmits the numbers of the receiving and transmitting slot. via TDM bus control channel 103 to PCS switch 111. Upon receiving the slot information, the PCS switch transmits this information to the PCS switch 112. The PCS switch 112 responds to the receive and transmit slot numbers to establish a connection between the wireless device 118 and the TDM bus 103.

Now consider another extension of the previous example where the wireless device 113 is busy on an active call through the base station 114 and the PCS switch 111. The wireless device 113 physically moves and begins communicating with the base station 119. The device Wireless 113 initiates a handover procedure by transmitting a setup message to PCS switch 112. They can also be used in other wireless protocols, which is a great advantage. The setup message specifies that a transfer is taking place. The PCS switch 112 examines its assignment table and determines that the phone number of the wireless device 113 is assigned to the PCS switch.

111. Based on this information, the PCS switch 112 transmits a message to the PCS switch 111 informing it that the wireless device 113 has performed a handover operation to the PCS switch 112. The PCS switch 111 then transmits the numbers of the receive slot and transmitted back to the PCS 112 switch. The PCS switch 112 uses this slot information to establish a conversation path between the wireless device 113 and the TDM bus 103 through the base station 119. The PCS switch 111 registers that the wireless device 113 is now active on the switch. PCS 112 and transfers all control messages received from the control computer 101 to the PCS switch 112. If the wireless device 113 has registered in a PCS switch other than the PCS 111 and 112 switches before registering in the PCS

112, the PCS switch 111 informed the other PCS switch of the registration in the PCS switch 112.

Fig. 2 shows the PCS switch 111 in greater detail. The switching processor 201 provides full control of the PCS 111 switch. The PCS 111 switch has an internal switching network consisting of the internal LAN bus 208, the internal TDM bus 209 and the SCOTCH circuit 207. This internal network was controlled by a network processor 202. Network processor 202 transmits slot information to BRI link interfaces 204206 over internal LAN bus 208. SCOTCH circuit 207 was controlled via cable 213. Network processor 202 controls the internal operation of the internal network and transmits messages between switching processor 201 and BRI link interface 204-206. The network processor 202 receives and transmits information through the LAN interface 203. The processor

ES 2 170 212 T3 switching 201 transmits and receives messages from the LAN bus 104 and TDM bus 103 through the LAN interface 211 and the “health and control interface” (SAKI) 212. The SCOTCH circuit 207 is a switching conferencing device. and a concentration handler that controls the transmission of voice and circuit-switched data between the internal TDM bus 209 and the TDM bus 103. Details on the LAN interfaces, the SAKI interface, and the SCOTCH circuit are provided in US Patent 3,311,576 and 5,329,579. Those patents are included herein by reference. The SAKI interface 212 is used by the switching processor 201 to receive and transmit on the control channel of the TDM bus 103.

The PCS switch 111 can emulate 24 BRI stations, which is an advantage; therefore, there can be 24 wireless device phone numbers assigned to the PCS switch 111. Also, the PCS switch 111 can have 12 BRI link interfaces, which is an advantage. One skilled in the art could well see that the number of phone numbers of assigned wireless devices and BRI link interfaces could increase or decrease.

Consider the previous example, where the wireless device 113 was registered to the PCS switch 111 through the base station 114. The base station 114 was interconnected to the PCS switch 111 through the BRI link 123 that ends at the BRI link interface 204. . When switching processor 201 receives the setup message indicating an incoming call from LAN bus 104 through LAN interface 211, switching processor 201 first checks to see if wireless device 113 is registered with any of the base stations. 114-117 attached to the PCS 111 switch. Since wireless device 113 is registered to base station 114, switching processor transmits the setup message to wireless device 113 via network processor 202, LAN interface 203, internal LAN bus 208, and wireless interface. BRI links 204. When a connection message is returned from the wireless device 113, the switching processor 201 transfers this connection message to the control computer 101 through the LAN interface 211 and the LAN bus 104. The connection acknowledgment message received from the control computer 101 it is routed to the wireless device 113 via the same route described for the setup message. When the control computer 101 transmits the numbers of the receive slot and transmitted through the control channel of the TDM bus 103, the SAKI interface 212 receives this information and transfers it to the switching processor 201. The switching processor 201 responds to slot information to control network processor 202 to allow SCOTCH circuit 207 through cable 213 to establish a route between internal TDM bus 209 and TDM bus 103. The network processor 202 also instructs the BRI link interface 204 which slots should be used for the information being communicated to and from the wireless device.

113 by transmitting a message on the internal LAN bus 208 through the LAN interface 203. Although BRI links have been used to connect base stations to individual PCS switches, one of ordinary skill in the art could well see that these links could be PRI links or links that use another protocol.

Fig. 3 shows the software architecture of the switching processor 201 of Fig. 2. The architecture shown in Fig. 3 is described in greater detail in US Patent 5,159,594 and 5,386,466. These patents are included herein by reference. Information transmitted by local clutter 303 to and from network processor 202 and LAN interface 211 is handled in the same manner as described in the two incorporated patents. Information from the SAKI interface 212 is inserted into a message by the deposit echo 303 and transmitted to the wireless manager 301 through the software layer 310-315. The parasite echo 303 is shown as a separate processor but, as described in the incorporated patents, it is a software process that was implemented in the switching processor 201. The wireless manager 301 controls the implementation of operations with respect to wireless devices. . The connection manager 302 controls the internal network connections of the PCS 111 switch.

FIG. 4 shows an activity table used by the assigned PCS switch to determine the following information for the telephone numbers assigned to that PCS switch. Column 404 defines the assigned phone numbers. Column 406 defines which PCS switch is the active PCS switch for a particular phone number, column 407 indicates the PCS switch from which a transfer has taken place, column 408 provides the current call status of the wireless device assigned to the phone. telephone number, and column 409 indicates which receive and transmit slots should be used by a PCS switch to communicate with the TDM bus 103 of Fig. 1.

Fig. 5 is the allocation table. Each PCS switch maintains a table like Fig. 5 that defines for each telephone number to which PCS switch that telephone number is assigned.

Figures 6-9 show in greater detail the operations carried out by the switching processors. Decision block 601 determines whether a message from a wireless device, which has established communication with a base station of the executing PCS switch, has transmitted a message to the PCS switch through the base station. If the answer is yes, decision block 602 determines whether the message is a call origination message. This type of setup message means that the wireless device is initiating a new call. If the answer is no, decision block 603 determines whether the message is a call transfer setup message. If the answer is yes, control is transferred to decision block 604 which determines if the device

ES 2 170 212 T3 wireless is assigned to this PCS switch. The assigned PCS switch is the switch to which the control computer 101 of Fig. 1 thinks the wireless device is connected as a wired station. If the decision in decision block 604 is no, control transfers to block 901 of FIG. 9. If the answer in decision block 604 is yes, block 605 transmits a transmit message "send transfer to another PCS switch" to the currently active PCS switch. The currently active PCS switch responds to this message to cease transmitting audio information to switching system 100. The currently assigned PCS switch accomplishes this by removing the talk path by itself. Block 606 then establishes a talk path through the execute switch and begins transmitting information with the TDM bus 103 of Fig. 1. Block 607 marks the execute PCS switch as the currently active PCS switch and transfers control. back to decision block 601.

Returning to decision block 602, if the answer is yes, control is transferred to decision block 608. This decision block determines if the wireless device is assigned to the PCS execution switch. If the answer is yes, block 609 processes the call origin normally before returning control to decision block 601. If the answer in decision block 608 is no, block 611 determines the assigned PCS switch of the wireless device, and block 612 sends a "transmit request setup" message to the assigned PCS switch. The "transmit request setup" message creates a message path that allows the assigned PCS switch to transmit messages between the current executing PCS switch and the control computer 101 of FIG. 1. Decision block 613 then determines whether a "transmission request accepted" message is returned from the assigned PCS switch. If the answer is no, block 617 sends a rejection message to the wireless device. If the answer in decision block 613 is yes, block 614 transmits the setup message to the assigned PCS switch which transmits it to control processor 101, and block 616 marks the execute PCS switch as the active PCS switch.

Returning to decision block 603, if the answer is no, control is transferred to decision block 618. This decision block determines whether a registration message was received from the wireless device. If the answer is no, decision block 619 determines whether a "lost communication with wireless device" message was received from the base station. If the answer is yes, block 621 sends an "alert of lost communication with wireless device" message to the assigned PCS switch. Block 629 removes all references to the wireless device from the internal tables of the PCS execution switch. If the answer in decision block 619 is no, 622 performs normal processing.

Returning to decision block 618, if the answer is yes, control is transferred to 626 which sends a registration notice message to the assigned PCS switch. Decision block 627 determines whether a "registration notice acknowledgment" message was received from the assigned PCS switch. If the answer is yes, block 628 registers the wireless device. If the answer in decision block 627 is no, block 623 transmits a rejection message to the wireless device, and block 624 performs debugging.

Returning to decision block 601, if the answer is no, control is transferred to decision block 701 of Fig. 7. Decision block 701 determines if the message is from the switching system 100. If the answer is only, decision block 702 determines if it is slot information. If the answer is yes, block 703 stores the slot information in the assigned PCS switch, which in this case is also the executing PCS switch. Control is transferred to decision block 704 which determines whether the wireless device is assigned to the assigned execution switch PCS. If the answer is yes, block 706 processes the message normally. If the answer in decision block 704 is no, decision block 707 determines whether a release message has been received from switching system 100. If the answer is yes, block 708 marks the wireless device as free and transfers control to block 709. This block transfers the received message to the currently active PCS switch as a transmit message. Finally, block 709 returns control to decision block 601 of FIG. 6.

Returning to decision block 701 of FIG. 7, if the answer is no, control is transferred to decision block 711. This decision block determines whether a transmit message has been received from another switch PC. If the answer is no, control is transferred to decision block 801 of FIG. 8. If the answer in decision block 711 is yes, decision block 712 determines whether the currently active PCS switch sent the message. If the answer is only, block 713 sends the transmission message to control processor 101 as if that message originated from the assigned PCS switch. If the answer in decision block 712 is no, decision block 714 determines whether the transmitted message is a handover setup message. If the answer is yes, block 719 sends the slot information for the wireless device to the transmitting PCS switch. In addition, block 721 transmits a communication cease message to the currently active PCS switch. Block 722 marks the transmit PCS switch as the currently active PCS switch before returning control to decision block 601 of Fig. 6. If the answer in decision block 714 is no, decision block 716 determines whether the transmitted message is an origin establishment message. If the answer is yes, block 718 transmits a setup message to switching system 100 before transferring control to block 722. If the answer in block 6

ES 2 170 212 T3 that decision 716 is no, block 717 performs an error elimination before transferring control to decision block 601 of FIG. 6.

Returning to decision block 711 of Fig. 7, if the answer is no, control is transferred to decision block 801 of Fig. 8. Decision block 801 determines if a "request establishment" message has been received. of transmission". If the answer is yes, the decision block 802 determines whether the wireless device that is the object of the "transmit request setup" message is assigned to the execution switch PCS. If the answer is no, block 803 sends a "transmission request or rejected" message to the transmit switch PCS before transferring control back to decision block 601 of FIG.

6. If the answer in decision block 802 is only, block 804 sends a "transmission request accepted" message.

Returning to decision block 801, if the answer is no, decision block 806 determines whether a "registration notice" message has been received. This message is transmitted over a PCS switch to the assigned PCS switch when a wireless device is registered. If the answer in decision block 806 is yes, decision block 807 determines whether the wireless device is assigned to the execution PCS switch. If the answer is no, block 811 sends a "registration notice reject" message back to the transmit switch PCS. If the answer in decision block 807 is yes, block 808 sends a "registration acknowledgment" message to the transmitting PCS switch, and block 809 marks the wireless device as being on the transmitting PCS switch at the same time. table shown in Fig. 4.

Returning to decision block 806, if the answer is no, control is transferred to decision block 812 which determines if the received message was a "lost communication with wireless device" warning message. If the answer is yes, decision block 816 determines whether to assign the PCS run switch to the wireless device. If the answer is no, control is transferred to block 818 which sends a rejection message of "lost communication with wireless device" to the transmitting PCS switch. If the answer in decision block 816 is yes, block 817 sends an acknowledgment message of "lost communication with wireless device" to the transmitting PCS switch. Returning to decision block 812, if the answer is no, decision block 819 determines whether the message was a "stop communication" message from the assigned PCS switch. This message is transmitted during a transfer from the current running PCS switch to another PCS switch. If the answer is no at decision block 819, block 814 processes any other messages normally. If the answer in decision block 819 is yes, block 821 removes the conversation path through the PCS execution switch, and block 822 removes all references to the wireless device established in the table shown in Fig. Four.

Returning to decision block 604 of FIG. 6, if the answer is no, control is transferred to block 901 of FIG. 9. Transfer to block 901 of FIG. 9 from decision block 604 means that it was received. a call transfer setup message for a wireless device not assigned to the executing PCS switch. When this occurs, the executing PCS switch must go to the assigned PCS switch to get the slot information and to get the assigned PCS switch to release the PCS switch from which the transfer is taking place. Block 901 determines the assigned PCS switch for the wireless device from the table shown in Fig. 5. Block 901 sends a "transmit request setup" message to the assigned PCS switch. Decision block 903 determines whether the "transmit request setup" message was accepted by the assigned PCS switch. If the answer is yes, block 904 transmits the setup message received from the wireless device to the assigned PCS switch for transmission to the control processor 101 of FIG. 1. Decision blocks 906 and 907 either wait for the reception of a connection message from the assigned PCS switch or a disconnection message from the wireless device. If decision block 907 determines a disconnect message, block 908 transmits a "disconnect transmission" message to the assigned PCS switch which will send a disconnect message to control processor 101 of FIG. 1 ending the attempt to originate a call. If a "connection transmission" message is received, decision block 907 transfers control to block 909 which sends a "connection acknowledgment transmission" message to the PCS switch assigned for transmission to the control processor 101. Decision block 911 determines whether a message is received from the assigned PCS switch slot. If the answer is no, block 914 sends a rejection message to the wireless device, and block 916 sends a "transmission disconnect" message to the assigned PCS switch. If the answer in decision block 911 is yes, block 912 establishes a talk path through the PCS run switch, and block 913 marks the PCS run switch as the currently active PCS switch before transferring control of the switch to it. back to decision block 901 of FIG. 6. If the answer in decision block 903 was no, blocks 914 and 916 are executed whose operations have already been described.