MXPA00002352A - Efficient message transmission in a mobile communication system - Google Patents

Abstract

The present invention reduces signaling between a mobile control node and one or more base stations. A common controller at each base station controls allocation of communication resources related to communications with mobile communication units. A single message is sent from the mobile control node to at least one of the base stations including information that identifies plural communication resources at the one base station, e.g., channel units corresponding to plural sector cells supported by the base station. The common controller at the one base station distributes the single message to the plural communication resources to be communicated ultimately by one of those communications resources to the mobile communication units. Signaling between a control node and plural base stations is therefore reduced by sending a single message from the control node to the base station that identifies plural communication resources at the base station rather than sending a separate message to each of the communications resources.

Description

EFFICIENT TRANSMISSION OF MESSAGES IN A MOBILE COMMUNICATION SYSTEM FIELD OF THE INVENTION The present invention relates to message transmissions between nodes in a mobile telecommunication system, and particularly to a method and apparatus for eliminating redundant or unnecessary message transmissions between the nodes. BACKGROUND OF THE INVENTION Mobile communication systems, such as, for example, cellular radiotelephone systems, are typically made in the form of a network of neighboring radio cells that together provide complete coverage of the area to which they are serviced. Mobile phone subscribers can move freely within the system area from one cell to another. A well-known digital radio system for mobile stations is the Global System for Mobile communication (GSM) (Global System for Communication of Mobile Stations). Although the present invention is sometimes described using GSM terms, the present invention has broad application and, in any way, applies to any type of cellular system or other communication system of mobile stations. Each cell receives service from a base station that includes radio transmission and reception equipment.

Several base stations are interconnected through a switching node sometimes known as a mobile switching center (MSC) which can also be connected to other networks, such as the public switched telephone network (PSTN). Alternatively, several base stations may be controlled by a base station controller (BSC) connected between the base stations and an MSC. Typically, several BSCs receive service from a single MSC that handles incoming calls and originates from other data and telephony communication networks. Whatever the node (MSC or BSC) interconnecting a group of base stations, this node controls radio-related functions such as paging, radio channel assignment, transfer, and power control. When a call is directed to a mobile station (MS) in the mobile communication system, said mobile station must be located and then voiced before a call connection can be established. These tasks are facilitated by having inactive mobile stations tuned to a base station control channel and through the periodic transmission by mobile stations of message registration messages in a base station control channel. As the mobile station moves from cell to cell, it is tuned again to the control channel corresponding to the current cell. In order to make subscriber location and paging efficient, cellular networks are often divided into location areas (Las) where a location area includes a group of cells. In accordance with that illustrated in Figure 1, a localization area 4 (LA4) includes cells 1-6. In this example five location areas LA1-LA5 constitute a mobile switching center (MSC) service area. The MSC service area is associated with a visitor location registration database (VLR) where the mobile stations currently within this service area are registered. When a call is routed to the MSC, the MSC reviews the VLR in order to identify the current location area where the called mobile station is registered. Then, a paging message is distributed to the base stations in the identified location area and transmitted by the base station transceivers within the location area. As the demand for base stations increases, the configuration of cells as well as the equipment compartment become more sophisticated. For example, Figure 2A shows a single cell that employs a unique omnidirectional antenna used by all base station transmitter receivers that service this cell. A more sophisticated configuration is shown in Figure 2B where a single base station site serves three sectors or cells with each sector cell of this type having its own directional antenna. Each sector cell shares the same set of transmission and reception equipment located at the base station site. Even when the same point of transmitter receiver equipment is used for several base station sectors, the paging messages are sent from the MSC node or BSC to the base station site for each of the sectors supported on this site. Thus, if the base station serves three sectors, three identical but separate paging messages are sent from the MSC or BSC to the base station site. Redundant message transmission creates unnecessary signaling, consumes transmission resource and increases data processing loads. A similar problem exists for other types of control messages sent to some or all of the base station sectors, for example, short messaging service (SMS) cell broadcast messages, system information messages used for inform mobile stations about network access procedures, etc. It is an object of the present invention to overcome this problem and eliminate unnecessary and redundant signaling between nodes in a mobile communication system. It is also an object of the present invention to minimize the processor load associated with sending several messages to the same node. It is a further object of the present invention to provide a unique message from the MSC or BSC in a mobile communication system to a base station site and have the base station site transmit the message to multiple sectors supported by this site. Another object of the present invention is to improve the speed and performance of mobile radio paging operations. COMPENDIUM OF THE INVENTION The aforementioned problems are solved and the aforementioned objects are fulfilled through this invention. In a mobile radio communication system that supports communications with several mobile radio units, each of several base stations includes radio transceivers and a common controller. The common controller assigns radio channels to the transceivers. A switching controller such as an MSC or BSC is connected to the base stations and controls the communications involving the radio units. The switching controller transmits a control message (for example a mobile station paging command, an SMS command, a system information message, etc.) to a selected (or several) base station. The control message identifies several channels associated with the selected base station. The common controller in the selected base station distributes the control message to each of the channels identified for radio transmission. Each channel may correspond, for example, to one of several sector cells supported by the base station, for example, a sector control channel or a sector paging channel. In other words, each sector cell shares the base station radio transceivers under the control of the common controller. Accordingly, the common controller in the base station distributes the control message that has been transmitted and received only once and that is transmitted in several channels, for example, a channel assigned to each sector. In this way, redundant control messages for each sector redundant control messages for each sector do not have to be transmitted between the switching controller (such as MSC or BSC) and the base station. If the control message is a paging message addressed to the mobile radio unit located in an area supported by the base station, only this single paging message will be sent from the switching controller to the base station. The paging message is then distributed by the common controller in the base station to each of the paging channels associated with each cell of sector supported by the base station. In specific embodiments different from the present invention, in single control message received by each selected base station from the switching controller indicates that the control message must be sent several times on several channels associated with the selected base station or it must be broadcast on all channels of a specific type associated with the selected base station. The method of the present invention consequently reduces the signaling between a control node and several base stations by sending a single message from the control node to at least one of the base stations including information identifying several communication resources in the base station instead of separately sending the message to each of the communication resources. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects, advantages and characteristics of the invention will be more fully understood by reading the following detailed description in combination with the drawings in which like reference numbers refer to similar elements throughout the description and in which: Figure 1 is a diagram of an area service center mobile switching that covers several areas of location; Figures 2A and 2B show configurations of single antenna and antenna cells per sector, respectively; Fig. 3 is a block diagram of function of a mobile communication system in which the present invention can be applied profitably; Figure 4 is a function block diagram illustrating with additional details the base station controller and a base station in accordance with the system depicted in Figure 3; Figure 5 shows a multiple-distribution message format in accordance with an exemplary embodiment of the present invention; Figure 6 shows a broadcast message format in accordance with an exemplary embodiment of the present invention; and Figure 7 is a flowchart illustrating exemplary procedures for implementing a method of compliance with an exemplary embodiment of the present invention. DETAILED DESCRIPTION In the following description, for purposes of explanation and not limitation, specific details are shown, such as particular modalities, signaling implementations, interfaces, techniques, etc. for the purpose of providing a thorough understanding of the present invention. However, it will be evident to a person skilled in the art that the present invention can be practiced in other modalities and applications (including applications other than cellular telephony) that come out of these specific details. For example, while the present invention is described in the context of an exemplary cell phone network employing a GSM terminology, those skilled in the art will note that such terminology is illustrative and in no way limiting and that the present invention can be implemented in any way. cell phone system. In other cases, detailed descriptions of well-known methods, interfaces, devices, and signaling techniques are omitted so as not to obscure the description of the present invention with unnecessary details. Figure 3 illustrates a mobile communication system 10 which is an exemplary environment in which the present invention can be implemented in a useful manner. A mobile communication system 10 includes a mobile gate switching center (GMSC) 12 that communicates with other external data and telephony communication systems 11 such as PSTN, ISDN, PSDN, etc. In accordance with what is described above, the GMSC 12 is the point in the communication system 10 into which the calls to the mobile stations (MS) 42 come in, and therefore each call ending at a mobile station must be routed by the mobile station. GMSC 12 to the appropriate MSC for delivery to the called mobile station. In Figure 3, a single MSC 14 is shown for illustration purposes; of course, additional MSCs can also be used. In order to carry out the initial routing functions, the GMSC 12 analyzes the incoming mobile call and extracts a mobile station identification number, for example, a mobile station ISDN number (MSISDN) in order to identify the registration of home location (HLR) where the mobile station is registered. The HLR stores a location information for each mobile subscriber unit and also contains a list of basic services and complementary services that a mobile subscriber can employ together with a current subscriber location number corresponding to a location registration address of the subscriber. visitor (VLR). The MSC 12 collides with HLR 16 information as to how it routes the call to the service area of the mobile switching center that is currently serving the mobile station. Using the service area information obtained from HLR 16, the call is routed to the appropriate service MSC 14 associated with a visitor location register (VLR) 18. VLR 18 includes a database containing information regarding all mobile stations currently located in the associated service area. Particularly, VLR 18 contains a temporary subscriber information required by MSC 14 to provide services to mobile / on-the-go mobile subscribers. When a mobile station moves into a new MSC service area, the associated VLR 18 requests data about the mobile station from the HLR 16 and stores it. Thus, if the traveling mobile station makes a call, the VLR 18 already has the necessary information to establish the call. Regarding the service MSC / VLR pair, the MSC 14 and the VLR 18 know, as a result of the regular mobile station registration procedures, the particular location area (LA9) in the MSC service area where it is located the mobile station called. The MCS 14 then sends a single paging message to a base station subsystem 22 at an interface "A" identified by the reference number 20 to a base station system (BSS) 22 including a base station controller. (BSC) 24 connected to several base stations (BSs) 28, 30, and 32. The communications between the base station controller 24 and the base stations 28, 30, and 32 are carried out through an interface "A" "identified in the reference number 26. Although it is not necessary to implement the present invention, in the illustrative embodiment, the base station system 22 performs or supervises the radio-based functions in the radio system. mobile communication and therefore manages radio communications with mobile stations through call set-up, call recording, handling of call transfer in progress between cells, etc. In handling connections of mobile stations during call set-up, the BSC 24 sends paging messages to the base stations within the identified location area. The base station then transmits the paging message through the air interface 40 in a control channel or a paging sub-channel incorporated in the control channel. When the called mobile station detects the paging message, it sends an acknowledgment on the control channel of the base station, a traffic channel is allocated, the mobile station calls, and a call connection is established if the mobile subscriber answers. The representative base stations BS1, BS2, and BS3 in a system of base stations 22 each include a common base station functional controller (BSFC) (known simply as "common controller") that controls a set of representative transceivers (TRX) 34a and 34b, 36a-36c, 38a, and 38b, respectively. In accordance with what is mentioned in the background section, the base station function controller (BSFC) and the transceiver equipment are placed in a single base station site but serve several sector or sector cells, each sector having its own antenna but sharing the common transceiver and controller equipment. For example, three base station sites in Figure 3 can each serve three or six sectors. Each sector cell typically receives a portion of the shared communication resources provided by the base station. Such communication resources include, for example, control channels, paging channels, broadcast channels, traffic channels, a portion of the BSFC 24 data processing expense, etc. Significantly, when a paging or other type of control message is to be communicated to several base stations and several sector cells, the MSC 14 simply transmits a single paging message or another control message to the station controller. base 24. The base station controller 24 transmits a single paging message or another control to the base station function controller at each base station in the identified location area currently serving the loco station call 42. The base station function controller then distributes the paging or other type of message for transmission in the paging channel or in another channel associated with each cell of sector supported by each base station. More specifically and with reference to the function block diagram illustrated in FIG. 4 and employing the example of a paging command, the base station controller 24 receives the paging command in an A 50 interface controller and provides it to a BSC function controller 52. The function controller 52 performs several functions, some of which were described above. One of these functions is to analyze the paging command to determine which location area and / or cell list are identified in the paging command. The BSC function controller 52 then sends the paging message through the interface controller A "54 on the interface A" to each base station in the designated location area or serving one of the sector cells. identified. Each base station includes an interface controller A "60, a base station function controller 62, and several radio receiver transmitter channel units (CUs) 64a, 64b, 64c, ... 64n. or channel unit covers any type of radio channel, for example, a frequency in FDMA systems, one or more time segments in TDMA systems, a chip code in a CDMA system, etc. Each station function controller 62 The selected base unit decides which channel units the paging command should transmit, some of the channel units, such as traffic channel units, are shared in the sense that they can be temporarily assigned to any of the sector cells supported by The base station, however, one or more of the channel units can be configured as a control, paging, or broadcast unit for each of the sector cells, in other words, each sector cell. it includes its own control, paging or broadcast channel. Each of the controllers 50, 52, 54, 60, and 64 can be implemented using programmatic, equipment, or both. The paging control message (or of another type) may be transmitted from the base station controller 24 on the A "interface to each of the base stations in any format that in some way specifies which channels it should the control message is distributed Two exemplary formats are described in connection with Figures 5 and 6. Figure 5 illustrates a multiple distribution message format 70. The multiple distribution message format includes a message type field 72., a channel field number 74, a list of sector channels 76, 78, and 80, and a message field 82. The message type may be, for example, a paging command or an SMS message. The number of channels 74 indicates the number of channel units that must transmit this type of message, while each sector channel that appears in the list can identify a control, paging, or broadcast channel for each sector cell. . Figure 6 shows a broadcast format message 90. Field 92 includes a type of message, such as a paging command. Field 94 sends a type of transmission indicating, for example, that the message in field 98 must be transmitted to all channel units. Field 96 can be used to qualify the type of channels, for example, all the paging channels, instead of all possible channel units. An exemplary method in accordance with the present invention is presented below in relation to the flow chart illustrated in FIG. 7. Initially, the BSC (or MSC) receives a control message (such as a paging command) and determines the location or list of cells in which one or more receiver (s) of this control message is located (block 100). The BSC (or MSC) then identifies from this location area or cell list the relevant base station sites to receive this control message (block 102). From the identified base stations, each base station function controller (BSSC) analyzes the received control message to determine its message type, eg, paging, short message command, etc. (block 104). The type of transmission is also identified to determine its type of transmission, for example, emission, multiple distribution, etc., (block 106). Then, the channel or the type of channel in which the control message is to be transmitted is identified (block 108). The identified channel units then transmit the control message (block 110). Thus, by sending only one control message to each base station that is ultimately provided to each sector cell supported by the base station, the present invention significantly decreases the signaling load at the MSC / BSC-station interface. base. As a result, the present invention also reduces the data processing load on the MSC / BSC as well as on the individual base stations due to this lower signaling load. In a paging context, the present invention improves the efficiency and overall performance of mobile paging operations. While the invention has been described in relation to what is currently considered to be the preferred and most practical embodiment, it will be understood that the invention is not limited to the modality presented, but rather has the purpose of encompassing several modifications and equivalent arrangements included within the spirit and scope of the appended claims. For example, while the illustrative mode was frequently described in terms of SMS and paging control messages, the invention can be applied to any type of message finally distributed in more than one channel supported by a base station.

Claims (22)

1. CLAIMS A communication system comprising: mobile radio units; several base stations, each base station includes several radio transceivers, and a common controller that assigns radio channels to some of the radio transceivers; and a control node connected to the base stations and controlling the communications involving the mobile radio units, where the control node transmits a message to a selected base station, the message identifies several radio channels associated with the station of selected base, and where the common controller in the selected base station distributes the message for transmission in each of the several identified radio channels associated with the selected base station.
2. The communication system according to claim 1, wherein the control node is a mobile switching controller (MSC).
3. The communication system according to claim 1, wherein the control node is a base station switching controller (BSC) which communicates with other communication systems through a mobile switching center.
4. The communication system according to claim 1, wherein the selected base station serves several sectors having corresponding sector antennas, each sector shares the radio transceivers and is controlled by the common controller.
5. The communication system according to claim 4, wherein the common controller causes the message to be transmitted on a radio channel assigned to each sector.
6. The communication system according to claim 1, wherein the selected base station serves several cells having corresponding cell antennas, each cell shares the radio transceivers and is controlled by the common controller.
7. The communication system according to claim 6, wherein the common controller causes the message to be transmitted on a radio channel assigned to each cell.
8. The communication system according to claim 1, wherein the message is a paging message addressed to one of the mobile radio units with only the sending of this paging message from the control nodes to the selected base station , and where the paging message is distributed by the controller common to each of the identified channels associated with this selected base station.
9. The communication system according to claim 1, wherein the message is a short message offered by a short messaging service to be distributed to several mobile radio units.
10. The communication system according to claim 1, wherein the message is a system information message to be distributed to several mobile radio units.
11. The communication system according to claim 1, wherein the message received by the base station selected from the control node indicates that the message must have a multiple distribution in several radio channels associated with the selected base station .
12. The communication system according to claim 1, wherein the message received by the base station selected from the control node indicates that the message must be sent several times through all the radio channels of a specific type associated with the selected base station.
13. A communication system comprising: mobile radio units; several base stations, each base station includes several radio transceivers, and a common controller coordination channel assigned to one of the transceivers; at least one of the base stations including cells of several sectors having antennas of corresponding sector cells, the common controller of a base station assigns a control channel for each sector cell to one of the base station transceivers; a switching controller connected to the base stations and controlling the handling of communications involving the mobile communication units; where the switching controller transmits a single paging command to selected base stations including the base station, the single paging command identifies several control channels associated with the various sector cells of the base station.
14. The communication system according to claim 13 wherein the common controller in each of the selected base stations distributes the unique message to each of the identified channels associated with this selected base station.
15. The communication system according to claim 13, wherein the single-paging command includes information regarding all channels associated with a selected base station where a paging message is to be sent.
16. The communication system according to claim 13, wherein the single call command includes a message type field and an identification of all channels associated with a selected base station.
17. The communication system according to claim 13, wherein the single call command includes a message type field and a transmission type field indicating that all channels of a specific type associated with a selected base station they must transmit a voice message associated with the paging command.
18. 18. The communication system according to claim 13, wherein the switching controller is a mobile switching controller (MSC).
19. 19. The communication system according to claim 13, wherein the switching controller is a base station switching controller (BSC) that communicates with other communication systems through a mobile switching controller (MSC).
20. 20. In a mobile communication network, a method for reducing signaling between a mobile control node and several base stations, comprising the steps of: establishing a common controller for each base station that controls the allocation of communication resources associated with radio communication with mobile communication units; sending a message from the mobile control node to at least one of the base stations including information identifying several communication resources in the base station; distribute the message to each of the communication resources in the base station; and transmit the message through the use of various communication resources.
21. 21. The method according to claim 20, wherein the communication resources include communication channels.
22. 22. The method according to claim 20, wherein each communication channel corresponds to a logical type of channel. The method according to claim 22, wherein the logical type of channel is a paging channel. The method according to claim 22, wherein the logical channel type is a short message service issuing channel. The method according to claim 20, wherein the message is a paging command. The method according to claim 20, wherein the base station includes a plurality of transceivers, each receiver transmitter supports one or more communication resources, and where one of the communication resources employs several transceivers. The method according to claim 20, wherein the base station includes a transmission and reception equipment shared by several sectors supported by the base station, each sector includes a corresponding sector antenna and is assigned one of several resources of communication in such a way that the message is communicated to mobile communication units that monitor communication resources in each of the various sectors. The method according to claim 20, wherein the message includes a message type field and an identification of all communication resources associated with the base station. The method according to claim 20, wherein the message includes a message type field and a transmission type field indicating that all communication resources of a specific type associated with the base station must transmit the message . 0. In a communication network that provides communication with mobile communication units, a method for reducing signaling between a control node and several base stations by sending a message from the control node to at least one of the base stations, which includes information that identifies several communication resources in a base station instead of sending the message separately from the control node to each of the communication resources. The method according to claim 30, further comprising: the distribution in the base station of the message to each of the various communication resources. The method according to claim 31, further comprising: transmitting in each of the various communication resources of the message to the mobile communication units.