KR100696334B1 - Soft hand-off method and between BTS diversity apparetus - Google Patents

Abstract

The present invention implements a diversity function device (hereinafter, abbreviated as "DVF") that performs a function of selecting a frame, and connects the DVF device and the base station through a separate direct path. The present invention relates to a diversity apparatus and a soft handoff method between base stations (BTSs) in an Internet protocol-based next generation mobile communication system in which an effective soft handoff is performed by connecting. A DVF apparatus for performing a diversity function (DVF) for channel selection and frame selection of a path; By implementing a LAN gateway that interfaces data between each base station and the IP core network, an effective soft handoff is performed.

In addition, the present invention provides a plurality of DVF devices for interfacing data between respective base stations via a direct path, and selecting diversity of data frames interfacing between each base station to enable diversity; By implementing a LAN gateway for interfacing data between each base station and the IP core network, an effective soft handoff is performed.

 IMT-2000 system, soft handoff, DVF, diversity, frame selection

Description

Diversity device and soft handoff method between base stations (BITS) in internet protocol based next generation mobile communication system {Soft hand-off method and between BTS diversity apparetus}             

1 is a diagram illustrating a network structure of a conventional IMT-2000 system.

2 is a structural diagram of an all IP network reference model contributed to 3GPP2 All IP Adhoc,

3 is a diagram showing an embodiment configuration of a diversity apparatus between base stations in an Internet protocol based next generation mobile communication system according to the present invention;

4 is a view showing the configuration of another embodiment of the inter-base station diversity apparatus in the Internet protocol-based next-generation mobile communication system according to the present invention,

5 is a flowchart illustrating an embodiment of a soft handoff method in an internet protocol based next generation mobile communication system according to the present invention;

6 is a flowchart illustrating another embodiment of a soft handoff method in an internet protocol based next generation mobile communication system according to the present invention.

<Explanation of symbols for the main parts of the drawings>

101 to 103, 301 to 306: base station

101a, 102a, 103a, 401 to 402: diversity function performing unit

200, 501, 502: LAN Gateway

602: source base station

603: Source DVF

604: target base station

605: PCF

The present invention relates to diversity and soft hand-off between base stations (BTS) in an internet protocol (IP) based next generation mobile communication system, and in particular, a diversity function for performing a frame selection function. Internet protocol based to implement an effective soft handoff by implementing a device (DiverSity Function: abbreviated as "DVF") and connecting the connection between the DVF device and the base station through a separate direct path. The present invention relates to a diversity apparatus and a soft handoff method between base stations (BTS) in a next generation mobile communication system.

1 is a diagram illustrating a network structure of a conventional IMT-2000 system.

Here, reference numerals 11 and 12 denote mobile stations MS capable of making calls while moving, reference numeral 20 denotes a base station BTS that interfaces data with the mobile stations 11 and 12 through an air interface. Reference numeral 30 denotes a control station (BSC) 30 for interfacing data with the base station (BTS) 20, reference numeral 40 denotes a mobile communication exchange (MSC), and reference numeral 50 denotes the mobile communication exchange 40 Represents an IMT-2000 core network that implements a core network.

The operation of the conventional IMT-2000 system configured as described above is as follows.

Each of the mobile stations 11 and 12 connects to a call with the base station 20 and receives service through the base station 20 when the connection is successfully established. The base station 20 assigns a corresponding channel to the mobile stations 11 and 12 under the control of the control station 30, and the control station 30 is connected to the mobile communication switch 40 so that the base station 20 While controlling the handoff and the like. The mobile communication switch 40 is connected to the core network 50 and serves to switch the call.

In such a conventional IMT-2000 system, there is a function called diversity.

In this case, diversity refers to a process of combining signals or selecting frames through multiple paths in order to improve service quality during soft handoff in a mobile communication system. The function of performing a function is performed at a base station, and the function of selecting a frame is performed at a control station.

Meanwhile, the two largest mountains in 3GPP (3 ^rd Generation Partnership Projects) and All IP networks issues to the entire network of IMT (International Mobile Telecommunication) -2000 network system based (Internet Protocol) IP in 3GPP2 of the recent International Conference on the Standardization of concrete The 2000 standard is expected to include specifications for implementing an all IP network. All IP networks have many differences compared to the existing IMT-2000 system network configuration (see FIG. 1).

2 is a diagram illustrating a structure of an all IP network reference model contributed to 3GPP2 All IP Adhoc.

Reference numerals 61 to 63 denote base stations which wirelessly interface data with mobile stations. Reference numeral 71 denotes a home subscriber subsystem (HSS) in which information specific to a specific user and terminal, such as a home location register (HLR), an AC, and the like, an internet-specific authentication algorithm and location information are stored. . Reference numeral 72 denotes a feature server responsible for call processing, and reference numeral 73 denotes a call control function unit that performs a function for call processing control. Reference numeral 74 denotes a roaming gateway (Roaming G / W) that performs a connection function with 2G network, and reference numeral 75 denotes a packet gateway (Packet G / W) for connection to the Internet network (not the IMT-2000 network). W).

Also, reference numeral 76 denotes a circuit gateway (Circuit G / W) for connection with a PSTN switching network, 77 denotes a legacy system, 78 denotes a PSTN network, and 79 denotes an internet network.

In this case, each gateway supports a dual protocol stack to be used for connection between networks using different protocols, performs functions such as address mapping, and there is a difference only in interworking with any network.

As shown in FIG. 2, one of the biggest differences is that the base station controller (BSC) disappears and the base transceiver system (BTS) itself is directly attached to the IP network, that is, the BTS becomes an IP node. Although the reference model of the All IP network has not been determined yet, at least 3GPP2 will adopt a configuration in which the BTS becomes an IP node.

Therefore, when the IMT-2000 system is implemented in such a configuration, the diversity function performed by the conventional control station should be implemented in the base station or the core network. In the IMT-2000 system, which is implemented to be standardized as shown in FIG. It is not considered.

The proposal to use All IP based on Packet Data Transfer for IMT-2000 System network, which has emerged as the biggest issue in 3GPP and 3GPP2, which is currently leading global communication standards, has been made since late 1999, especially in the case of 3GPP2. At the two Adhoc meetings in December 1999 and January 2000, we gained a great deal of opinion on the reference model of the All IP network. Looking at the reference models of the articles published here, it can be seen that by distributing the functions of the existing BSC to the BTS and core network, the BSC device itself disappears and eventually the BTS becomes an IP node (see FIG. 2).

Given this trend, the BSC's functions must be distributed to the BTS and the core network. In the process, the following problems must be addressed.

During soft handoff between BTSs, the data transmitted from the terminal to the network is improved through the diversity function. That is, the quality of data is improved by combining or transmitting a frame through data transmitted through multiple paths. However, among these, the frame selection function must be transferred to the BTS or the core network because it is a function existing in the BSC, and it should be placed in the BTS because it is difficult to select a frame in the core network. However, in this case, since problems such as frequent data generation between BTSs may occur, a solution to this, that is, selection of a suitable device location is required.

Another function to consider when selecting a device to select a frame is that the quality of service is not sufficiently guaranteed in the Internet. Therefore, in the case of a frame selection function requiring real time processing, a problem must be solved for the connection method between the device in which the function is implemented and the BTS.

Therefore, the present invention has been proposed to solve various problems that occur when the base station is switched to the IP node as described above,

An object of the present invention is to implement a diversity function device that performs a frame selection function, and to connect the DVF device and the base station through a separate direct path so that effective soft handoff is performed. An object of the present invention is to provide a diversity device and a soft handoff method between base stations (BTS) in an Internet protocol based next generation mobile communication system.

The present invention for achieving the above object,

First of all, the functional device that selects the frame is divided into a device independent from the BTS (DVF), and the connection between the device and the BTS is connected through a separate direct path instead of the existing internet path. The reason for using the direct path is to effectively perform the frame selection function, which is an important feature of the real-time processing, because the existing internet does not satisfy the real-time characteristics sufficiently. Of course, if the internet can guarantee sufficient real-time processing in the future, the direct path can be replaced with the internet.

Regarding the location of the DVF, there is a method of placing a DVF device in each BTS, and a method of sharing the DVF in several BTS units.

Hereinafter, described in detail with reference to the accompanying drawings, preferred embodiments of the present invention according to the technical spirit as described above.

FIG. 3 is a diagram illustrating an embodiment configuration of a diversity apparatus between base stations in an internet protocol based next generation mobile communication system.

Reference numerals 101 to 103 denote base stations which wirelessly interface data with mobile stations, and each base station is provided with DVFs 101a, 102a and 103a for performing a diversity function.

In such a configuration, each of the base stations 101 to 103 combines a plurality of channel signals or selects frames in the DVF provided internally.

Reference numeral 200 denotes a RAN gateway in charge of connection with a RAN network.

The functions of each other block are the same as those of the blocks corresponding to the same reference numerals in FIG. 2 and briefly described below.

Reference numeral 72 denotes a feature server responsible for call processing, and reference numeral 73 denotes a call control function unit that performs a function for call processing control. Reference numeral 74 denotes a roaming gateway (Roaming G / W) that performs a connection function with 2G network, and reference numeral 75 denotes a packet gateway (Packet G / W) for connection to the Internet network (not the IMT-2000 network). W).

Also, reference numeral 76 denotes a circuit gateway (Circuit G / W) for connection with a PSTN switching network, 77 denotes a legacy system, 78 denotes a PSTN network, and 79 denotes an internet network.

4 is a diagram illustrating an embodiment configuration of a diversity apparatus between base stations in an internet protocol based next generation mobile communication system.

Reference numerals 301 to 306 denote base stations which wirelessly interface data with mobile stations. These base stations each perform only a function of combining a plurality of channel signals.

Reference numerals 401 to 402 denote a DVF that performs a diversity function. In FIG. 4, unlike FIG. 3, the DVF 401 and 402 are implemented as separate devices from the base stations to independently perform the diversity function. . That is, the frame selection function performed by the conventional control station is performed.

In addition, reference numerals 501 and 502 denote the RAN gateway in charge of connection with the RAN network, similarly to the RAN gateway 200 of FIG. 3.

The functions of each other block are the same as those of the blocks corresponding to the same reference numerals in FIG. 2 and briefly described below.

Reference numeral 72 denotes a feature server responsible for call processing, and reference numeral 73 denotes a call control function unit that performs a function for call processing control. Reference numeral 74 denotes a roaming gateway (Roaming G / W) that performs a connection function with 2G network, and reference numeral 75 denotes a packet gateway (Packet G / W) for connection to the Internet network (not the IMT-2000 network). W).

Also, reference numeral 76 denotes a circuit gateway (Circuit G / W) for connection with a PSTN switching network, 77 denotes a legacy system, 78 denotes a PSTN network, and 79 denotes an internet network.

5 is a flowchart illustrating an embodiment of a soft handoff method in a next generation mobile communication system based on the Internet Protocol IP according to the present invention.

In this case, the traffic transmission procedure of the soft handoff time between the mobile station (MS) and the RAN devices is shown.

In step S1, if the strength of the pilot of the BTS included in the neighbor set among the pilot offset lists held by the mobile station exceeds the T_ADD value, the mobile station sends PSMM_msg to the Source BTS.

In step S2, the Source BTS analyzes PSMM_msg and sends a Handoff Request message to the Target BTS.

In step S3, the source BTS starts sending forward frames to the target BTS, and in step S4, the target BTS transfers forward frames to the mobile station as soon as it is synchronized.

In step S5, as soon as the target BTS receives the first forward frame from the source BTS, the target BTS sends a reverse frame, which is an idle frame. The Reverse Frame contains enough time adjustment information to synchronize.

In step S6, the Target BTS sends a Handoff Request Ack message indicating Cell Addition success to the Source BTS.

In step S7 the Target BTS establishes a Link and sends a Traffic Channel Status message to the Source BTS.

In step S8, the source BTS sends an extended handoff direction message to the mobile station to add a new cell to the active set.

In step S9, the mobile station sends an MS Ack Order to the source base station, and in step S10, the mobile station notifies by sending a handoff completion message that a new cell has been added to the active set.

In step S11, the Source BTS informs the mobile station that it has received a Handoff Completion message.

In step S12, the mobile station sends traffic to the source BTS and the target BTS.

In steps S13, S14, and S15, the source BTS delivers traffic to the DVF device through the internal connection, and the target BTS delivers traffic through the direct path to the DVF device of the source BTS.

In step S16, the DVF of the Source BTS performs an error check, selects high-quality traffic, and sends it to the PCF.

6 is a flowchart illustrating another embodiment of the soft handoff method according to the present invention.

In this case, the Soft Handoff instantaneous traffic transmission procedure between the mobile station (MS) and the RAN devices is shown.

In step S21, if the strength of the pilot included in the neighbor set among the pilot offset lists held by the mobile station exceeds the T_ADD value, the mobile station sends PSMM_msg to the Source BTS.

In step S22, the Source BTS analyzes PSMM_msg and analyzes whether the Pilot Offset value is in the same RAN Gateway group, and if it is in the same group, sends a Handoff Request message to the Target BTS.

In step S23, the Source BTS starts sending Forward Frames to the Target BTS.

In step S24, the Target BTS transfers Forward Frames to the mobile station as soon as synchronization is established.

In step S25, as soon as the target BTS receives the first forward frame from the source BTS, the target BTS sends a reverse frame which is an idle frame. The Reverse Frame contains enough time control information to synchronize.

In step S26, the Target BTS sends a Handoff Request Ack message indicating Cell Addition success to the Source BTS.

In step S27, the Target BTS establishes a Link and sends a Traffic Channel Status message to the Source BTS.

In step S28, the source BTS sends an extended handoff direction message to the mobile station to add a new cell to the active set.

In step S29, the mobile station sends an MS Ack Order to the source base station, and in step S30, the mobile station notifies by sending a handoff completion message that a new cell has been added to the active set.

In step S31, the Source BTS informs the DVF of the Source BTS and Target BTS information and makes a Frame Selection request.

In step S32, the Source BTS informs the mobile station that the BS Ack Order has received a Handoff Completion message.

In step S33, the mobile station sends traffic to the source BTS and the target BTS.

In step S34, the source BTS and the target BTS deliver traffic to the DVF device using the direct path.

In step S35 and S36, the DVF performs an error check, selects high-quality traffic, and delivers it to the source BTS through the direct path.

In step S37, the Source BTS transfers the traffic to the PCF via the internet path, thereby terminating the soft handoff procedure.

According to the present invention described above "the diversity apparatus and soft handoff method between base stations (BTS) in the next generation mobile communication system based on the Internet protocol", the specific system configuration for the RAN field in the configuration of the All IP-based IMT-2000 system Since it can be provided, not only can promote the activation of the All IP network, there is an advantage that the system configuration of the RAN field among the All IP network is possible.

In addition, by connecting the DVF device and the base station through a separate direct path (Direct Path) there is an advantage to enable effective soft handoff.

Claims (4)

delete A diversity device between base stations (BTS) in an internet protocol based next generation mobile communication system, A plurality of DVF devices positioned separately from each of the base stations to interface the data between the respective base stations through a direct path, and to select diversity of the data to be interfaced between the respective base stations to enable diversity; Diversity device between base stations (BTS) in a next generation mobile communication system based on the Internet Protocol, characterized in that it comprises a LAN gateway for interfacing data between each base station and the IP core network. A soft handoff method of an IMT-2000 system consisting of a mobile station, a source base station, a DVF device, a target base station, and a PCF, Transmitting, by the mobile station, the PSMM_msg to the source BTS when the strength of the pilot of the BTS included in the neighbor set among the pilot offset lists held by the mobile station exceeds the T_ADD value; The Source BTS analyzing PSMM_msg and transmitting a Handoff Request message to a Target BTS; The source BTS starts sending forward frames to the target BTS, and the target BTS forwards the forward frames to the mobile station as soon as the synchronization is synchronized; Transmitting, by the target BTS, a reverse frame, which is an idle frame, upon receiving a first forward frame from a source BTS; The target BTS transmitting a Handoff Request Ack message indicating a Cell Addition success to a Source BTS; Setting a link by the target BTS and transmitting a Traffic Channel Status message to a source BTS; The Source BTS transmitting an Extended Handoff Direction message for adding a new Cell to the Active Set to the mobile station; The mobile station transmitting an MS Ack Order to a source base station; Notifying, by the mobile station, via a handoff completion message that a new cell has been added to an active set; Sending, by the Source BTS, a BS Ack Order to the mobile station indicating that a Handoff Completion message has been received; The mobile station transmitting traffic to a source BTS and a target BTS; The source BTS delivers traffic to the DVF device through an internal connection, and the target BTS delivers traffic through the direct path to the DVF device of the source BTS; The DVF of the Source BTS performs an error check, selecting a high-quality traffic, and transmitting the same to a PCF, wherein the soft handoff between base stations (BTS) is performed. A soft handoff method of an IMT-2000 system consisting of a mobile station, a source base station, a DVF device, a target base station, and a PCF, Transmitting, by the mobile station, the PSMM_msg to the Source BTS when the strength of the pilot included in the neighbor set among the pilot offset lists held by the mobile station exceeds a T_ADD value; Analyzing, by the Source BTS, whether the Pilot Offset value is in the same RAN Gateway group by analyzing PSMM_msg, and transmitting a Handoff Request message to the Target BTS if it is in the same group; Transmitting, by the Source BTS, Forward Frames to a Target BTS; The target BTS forwarding Forward Frames to the mobile station after synchronization is established; Transmitting, by the target BTS, a reverse frame, which is an idle frame, upon receiving a first forward frame from a source BTS; The target BTS transmitting a Handoff Request Ack message indicating a Cell Addition success to a Source BTS; Setting a link by the target BTS and transmitting a Traffic Channel Status message to a source BTS; The Source BTS transmitting an Extended Handoff Direction message for adding a new Cell to an Active Set to the mobile station; The mobile station transmitting an MS Ack Order to a source base station; The mobile station transmitting a handoff completion message to the source BTS indicating that a new cell has been added to the active set; The Source BTS informing the DVF of the Source BTS and Target BTS information and making a Frame Selection request; Transmitting, by the Source BTS, a BS Ack Order to the mobile station indicating that a Handoff Completion message has been received; The mobile station transmitting traffic to a source BTS and a target BTS; Transmitting traffic to a DVF device using a direct path between the source BTS and the target BTS; The DVF performs an error check, selects high quality traffic, and transmits the selected traffic to the source BTS through a direct path; The source BTS is a soft handoff method between base stations (BTS) in the Internet protocol-based next generation mobile communication system, characterized in that the step of delivering traffic to the PCF through the Internet path.

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