KR20100110033A - Cell update message active controlling method and mobile telecommunication system for using the same - Google Patents

Abstract

The present invention relates to a method for supporting multi-service by actively controlling the size of a cell update message and a mobile communication system using the same. The method and system determine whether RACH measurement is included in a Cell Update message transmission, calculate the size of the Cell Update message when the Cell Update message includes the RACH measurement, and divide the SDU by the size of the Cell Update message. The Cell Update message is transmitted when the size is less than the allowable size, and the number of cells is reduced when the SDU division allowance size is exceeded, and the Cell Update message is calculated by calculating the size of the Cell Update message corresponding to the reduced number of cells. Determines whether a message is sent.

Description

Cell update message active control method and mobile communication system using same {CELL UPDATE MESSAGE ACTIVE CONTROLLING METHOD AND MOBILE TELECOMMUNICATION SYSTEM FOR USING THE SAME}

The present invention relates to a mobile communication system, and more particularly, to a method for supporting multi service by actively controlling the size of a cell update message and a mobile communication system using the same.

Recently, due to the rapid development of communication, computer network, and semiconductor technology, various services using wireless communication networks are provided, and the demands of consumers are increasing day by day, and the global market for wireless internet services is exploding. It is a trend. Accordingly, a service provided by a mobile communication system using a wireless communication network is developing not only a voice service but also a multimedia communication service for transmitting various data.

Global System for Mobile Communications (GSM) or Interim Standard (IS) -95 is a second generation mobile communication method that provides voice-oriented services. GSM, a Time Division Multiple Access (TDMA) scheme, was commercialized around Europe in 1992. IS-95, a Code Division Multiple Access (CDMA) scheme, It is commercially available in Korea and the United States.

The third generation mobile communication system uses a CDMA scheme, and is based on the 3rd Generation Partnership Project (3GPP) and the 3rd Generation Partnership Project (3GPP2) based on the synchronization between the base stations based on the asynchronous between the Node Bs, or CDMA2000. Separated by). 3GPP, also called Universal Mobile Telecommunications System (UMTS), is a European standard, and 3GPP2, also called CDMA2000, is an American standard.

One of the third generation mobile communication technology standards is WCDMA (Wideband Code Division Multiple Access) method. Technically, WCDMA is a broadband spread-spectrum mobile radio interface that uses direct sequence code division multiple access signal processing (CDMA) to support higher speeds and more users than time division multiple access (TDMA) used in 2G GSM networks. In addition, WCDMA is also called asynchronous third generation mobile communication by distinguishing technical differences from CDMA 2000 1X, which is a synchronous third generation mobile communication. A network according to the WCDMA standard (hereinafter referred to as a "WCDMA" network) provides services such as video call, high speed downlink packet access (HSDPA) and high speed uplink packet access (HSUPA).

A typical WCDMA network is a user connected to a UMTS Terrestrial Radio Access Network (UTRAN), a Core Network (UTRAN), and a UTRAN including a Radio Network Controller (RNC) and a Node-Base Station (Node-B). It includes a user equipment (UE).

The core network handles voice information and supports various Non-Access Stratum (NAS) protocols to handle mobile control centers (MSCs), which perform functions such as call control and mobile device mobility, and to handle voice information and to public switched telephone networks. ; Gateway Mobile Switching Center (GMSC) that connects WCDMA network with general telephone voice communication network), and SGSN which handles packet information indicating unit of data and detects user terminals coming into its area and controls packet transmission and reception. (Serving GPRS support node), a gateway GPRS support node that handles packet information, connects the Internet network with the core network, and forms a logical path through which packets can be transmitted and received to and from user terminals using user terminal information input from SGSN. And HLR (Hom) which stores the user's location information and performs terminal authentication procedure and registration in WCDMA network. e Location Register).

The radio network controller (RNC) plays the same role as a base station controller (BSC) in GSM, and the Node-B plays the same role as a base transceiver site (BTS) in GSM. The radio network controller supports radio resource management, handover of user terminals, and an interface between other network elements, and Node-B is a base station supporting both frequency division duplex (FDD) and time division duplex (TDD) modes. It performs the function of accessing and connecting with wireless network controller.

In the structure of a radio access protocol that is responsible for data transmission in WCDMA, the same can be applied to a UE and a UTRAN. In the UE, all these protocols are contained within a single entity, but in the UTRAN, each network component can be distributed. Compared with the commonly known Open System Interface (OSI) reference model, the physical layer corresponds to the first layer L1, and the upper MAC, RLC, PDCP, and BMC layers correspond to the second layer L2. The exchange of information between protocol layers is accomplished through a virtual access point called a service access point (SAP).

First, the lowest radio physical layer (Radio Physical Layer) is responsible for the transmission of data over a radio channel between the UE and the UTRAN. Since the physical layer supports WCDMA technology, related technologies such as data multiplexing, channel coding, spreading, and modulation are applied. In addition, in the wireless environment, since the radio signal changes from time to time according to the movement of the terminal or the surrounding environment, various methods for correcting the demand are required. The upper MAC layer is connected through a transport channel.

The radio data link layer corresponding to the second layer of the OSI reference model includes a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a broadcast / multicast layer (BMC). Control) layer.

 The MAC layer is a layer responsible for mapping between logical channels and transport channels. The MAC layer selects an appropriate transport channel for transmitting data transmitted from the RLC layer, and supplies necessary control information to a header of a MAC protocol data unit (PDU). Add to Special features include Radio Resource Management and Measurement. The radio resource management function controls the transmission of data by setting the operation of the MAC layer based on various MAC parameters transmitted from an upper RRC (Radio Resource Control) layer, and the mapping relationship between logical channels and transport channels. Or a function of multiplexing and transmitting data by a scheduling function. The measurement function is a function of measuring a traffic volume of a UE and reporting it to the UTRAN. The UTRAN may change the setting of the MAC layer based on the information measured by the MAC layer of the UE, thereby efficiently managing radio resources.

 The RLC layer is located above the MAC layer to support reliable transmission of data. In order to configure data of an appropriate size for the radio section, RLC service data units (SDUs) transmitted from a higher layer are segmented and concatenated. The RLC layer of the receiver supports a reassembly function of data to recover the original RLC SDU from the received RLC PDUs. Each RLC entity may operate in a transparent mode, an unacknowledged mode, or an acknowledgment mode according to a processing and transmission method of an RLC SDU. In case of operating as TM, RLC SDU can be delivered to RLC SDU without adding any header information to MAC layer.In case of UM, RLC PDUs can be divided and connected to configure RLC PDUs. Header information including the number is attached. UM does not support retransmission of data. When operating as an AM, the RLC PDU can be configured using the partitioning / connection function of the RLC SDU and retransmitted when a packet fails to be transmitted. Various parameters and variables are used for the retransmission function of the AM such as the transmission window, the reception window, a timer, and a counter.

 The PDCP layer is used only in the packet switched area, and may compress and transmit the header of the IP packet to increase the transmission efficiency of packet data in a wireless channel. This function is called header compression. In R99, RFC 2507, which is an IP packet header compression method, is used. In R4, a header compression method of real-time packet data called RFC 3095 (ROHC) is additionally supported. In addition, the PDCP layer manages a sequence number to prevent data loss during SRNS relocation.

The BMC layer delivers cell broadcast messages delivered from CBC (Cell Broadcast Center) of the core network to various UEs through a common channel. A service supported by the BMC layer of R99 is called a CBS (Cell Broadcast Service), and a BMC message for CBS is transmitted to all terminals in a cell using CTCH / FACH.

Finally, Radio Resource Control (RRC) layer provides various control functions related to setting / changing / release of lower layer in UE or UTRAN. To this end, the RRC layer provides a path for directly exchanging control information with a lower layer, which is called C-SAP (Control SAP) in order to distinguish it from a general SAP. Various RRC procedures are defined between the UE RRC layer and the UTRAN RRC layer for mutual control information exchange. Most RRC procedures are used for the purpose of setting and controlling the function of the terminal. In addition, the RRC message may include control messages descending from the Non-Access Stratum (NAS) protocol, which are transparently transmitted to the terminal or the core network without being read in the UTRAN.

The data transmitted by the overall protocol structure may be divided into two areas, a user plane and a control plane, depending on the type. The user plane is an area in which user traffic information such as voice or IP packet is transmitted, and the control plane is an area in which control information is transmitted, such as network interface or call maintenance and management. Data delivered by the RRC layer is included in the user plane, and data transmitted through the PDCP layer and the BMC layer belongs only to the user plane. The RLC layer may belong to the user plane or may belong to the control plane according to the type of the connected higher layer. That is, when the RLC layer is connected to the RRC layer, it belongs to the control plane, and in the other case, the RLC layer is located in the user plane.

In the concept of a bearer service provided by WCDMA, a service for transmitting data through a radio bearer is provided between the terminal and the UTRAN. In a more accurate sense, a data transmission service provided to a higher layer by a second layer is defined as "Radio Bearer" (RB). Therefore, the characteristics of the radio bearer are determined by the characteristics of the lower protocol layer, transport channel, physical channel, and the like. To distinguish from a general radio bearer transmitting user data, a radio bearer for transmitting control plane data is also called a signaling radio bearer (SRB). The radio bearer may provide a bidirectional or unidirectional service to a higher layer. The direction of the service provided may be determined by the RLC entity using it. For example, an AM RLC entity provides a bidirectional data transfer service, and an RLC entity operating in UM or TM only provides a unidirectional service. A maximum of 32 radio bearers may be defined between the terminal and the UTRAN, some of which are allocated to the SRB.

FIG. 1 is a flowchart showing an RRC state transition process from a CELL_DCH state to a Cell_PCH state, and FIG. 2 is a flowchart showing a call processing procedure in a Cell_PCH or URA_PCH state.

In the WCDMA system, when there is no transmission / reception data of a user in a PS call, the UTRAN sets the RRC state so that the UE does not use a dedicated channel (DCH) or a shared channel (HS-DSCH) for efficient use of radio resources. Transition from Cell_FACH to Cell_PCH or URA_PCH. When the user attempts to add a voice (AMR), video call, or PS RAB to the terminal that has been in this state transition, the RRC of the UE should transmit a Cell Update message through the RLC TM SAP using RB0 (SRB0). The RRC of the UE transmits the measurement result for the corresponding cells in the Measurement result on RACH IE of the Cell Update message according to the Maximum number of reported cells on RACH IE value of SIB (Systrm Information Block) 11 when transmitting the Cell Update message. Should be. TB size in RLC TM mode defined in TS25.331 in 3GPP is 168 bits and consists of RRC payload 166 bits + 2 bits MAC header. If the subscriber attempts CS service while the PS call transitions to Cell_FACH or Cell_PCH / URA_PCH state, the CS + PS multiservice call is established. The Cell Update message transmitted when the multiservice call is established includes information on the PS domain, CS domain information, and RACH measurement results. In this case, the RRC PDU size of the Cell Update message exceeds 166 bits, and since the SDU splitting is not allowed in the RLC TM mode used by RB0, the RRC of the UE cannot transmit the Cell Update message and thus cannot attempt a CS call. . In addition, if the user does not change the RRC state to the Cell_DCH state by releasing the PS call or transmitting data to the PS call, the CS call continues to fail.

The present invention provides a method for supporting multi-service by actively controlling the size of a cell update message and a mobile communication system using the same.

According to an aspect of the present invention, there is provided a method of actively controlling a cell update message, comprising: a) determining whether to include a RACH measurement when transmitting a Cell Update message; b) calculating the size of the Cell Update message if the Cell Update message includes the RACH Measurement; c) transmitting the Cell Update message when the size of the Cell Update message is less than or equal to the SDU division allowable size and reducing the number of cells when the SDU division allowance is exceeded; And d) repeating step c) by calculating a size of the Cell Update message corresponding to the reduced number of cells.

In addition, the mobile communication system of the present invention determines whether to include the RACH measurement when transmitting the Cell Update message, and calculates the size of the Cell Update message when the Cell Update message includes the RACH Measurement, The cell update message is transmitted when the size is smaller than the SDU partitioning allowed size. When the SDU partitioning size is exceeded, the number of cells is reduced, and the size of the cell update message corresponding to the reduced number of cells is calculated. To control the Cell Update message.

According to the present invention, by solving a 3GPP specification problem that may occur due to the inclusion of RACH measurement when transmitting Cell Update message in RLC TM mode, it is impossible to transmit Cell Update message that may occur in Cell_FACH state or Cell_PCH / URA_PCH state. This solves the problem of not being able to set up multiple RABs.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions will not be described in detail if they obscure the subject matter of the present invention.

3 is a block diagram showing the configuration of a mobile communication system according to an embodiment of the present invention.

First, in the mobile communication system, the user equipment (UE) 130 and the Node-B 122 of the UTRAN 120 communicate with each other through a Radio Resource Control (RRC) protocol. The broadcast message to the controlling cell area is defined as an RRC message. The RRC message may include control messages descending from the Non-Access Stratum (NAS) protocol, which are not read within the UTRAN 120 and are transparent to the UE 130 or the Core Network 110. It is passed transparently. The channel frequency unit assigned to one Node-B 122 is represented by a Frequency Assignment (FA) (for example, 4FA in the case of WCDMA), and the FA is an identifier for identifying a cell in the physical layer (for example, WCDMA). PSC (Primary Scrambling Code).

The core network 110 of the WCDMA network includes three domains: a circuit switched (CS) domain, a packet switched (PS) domain, and a broadcast switched (BS) domain. Each domain is connected to the RNC 121 of the UTRAN 120 using the Iu interface.

The CS (Circuit Switched) domain is a method of transmitting data by allocating a dedicated channel (meaning that a sender and a receiver are connected 1: 1) in a physical layer. MSC, HLR and AuC (Authentication Center) play a major role in the connection. Typical functions include the MM (Mobility Management) protocol, a connection management protocol, and a voice call that switch the connection to a nearby Node-B 122 as the UE 130 used in the NAS stage moves. CC (Call Connection) protocol that manages the transmission and reception, SMS (Short Message Service) that is in charge of connection with the core network in the voice call transmission and reception procedure, and means the call reconnection and text service. In general, user call voice data is transmitted and received using the CS domain.

The PS (Packet Switched) domain is used to transmit user data in packet units. SGSN and GGSN play a major role in this connection. In addition to voice data carried by the CS domain, video and various control commands are transmitted and received using the PS domain. Typically, there is a Session Management (SM) protocol using a GPRS Mobility Management (GMM) protocol and a PS bearer, which is generally faster than the CS domain.

A BS (Broadcast Switched) domain is a domain used when it is necessary to collectively transmit data to multiple UEs in a certain area.

In the UTRAN 120 of the WCDMA network, when the UE 130 transmits an RRC Connection Request message to the Node-B 122 to set up a call for a call request, the Node-B 122 has its own. Check the radio resource status.

The RRC protocol is responsible for creating, modifying, and releasing an RRC connection that is responsible for transmitting an RRC signaling message. The RRC connection occurs between the UE 130 and the UTRAN 120, where the NAS provides transport services using the RRC connection. Only one RRC protocol is generated in the UE 130, but the UTRAN 120, which needs to connect a plurality of UEs 130, has a plurality of RRC protocols. Another function of the RRC protocol is with respect to a radio access bearer (RAB). The RAB is responsible for generating voice and packet data, ie, user plane connection, going up from the UE 130 of the NAS to the core network. And, RRC protocol is in charge of mobile mobility support. Various handovers are controlled to ensure free mobility of the terminal. In addition, it updates the Cell, URA (UTRAN Registration Area, area) area to effectively locate the UE in the network.

The UE 130 is set to be in a predefined state according to the RRC connection state. The RRC connection state includes a CELL_DCH state, a CELL_FACH state, a CELL_PCH state, and a URA_PCH state.

The CELL_DCH state is a state that is entered when the RRC connection request or the UTRAN 120 changes the connection setting. The RNC of the UTRAN 120 includes location information about the UE. The UE 130 may use all resources allocated or shared in the CELL_DCH state and may be available within the range of the TCF received from the RNC 121. In addition, in the CELL_DCH state, the UE 130 may be identified by a physical layer technology (for example, channelization or scrambling code). In the CELL_DCH state, movement to all states is possible.

In the CELL FACH state, uplink can be used. When the UTRAN 120 makes an RRC connection, the UE 130 uses a common channel or enters the CELL_FACH state as part of a radio bearer (RB) reconfiguration. The common channel is used differently depending on the amount of data transmission. RACH is used for low uplink transmission amount and CPCH is used for large transmission amount, respectively. The location information of the UE 130 is known toward the cell, and a cell update message is formed based on the location information of the UE 130. The cell update message is a means for accurately identifying the location information of the UE 130. The UE 130 may be recognized by receiving a temporary identifier of u-RNTI from the RNC 121 in the cell.

The fundamental purpose of the CELL_PCH state is to reduce battery usage by using DRX (Discontinous Reception) parameters and to inform the WCDMA network of the exact location of the UE 130. In the WCDMA network, a paging message transmitted to the UE 130 periodically is transmitted only to the cell to which the UE 130 belongs. The CELL_PCH state can be accessed only through the CELL_DCH and CELL_FACH states, and the cell information can be updated by periodically checking the cell information. When the UTRAN 120 receives the paging message, the UE enters the CELL_PCH state and transmits a response message from the UE 130.

The paging message refers to a DRX parameter periodically transmitted from the core network 110 or the UTRAN 120 to the UE 130 in order to control the sleep mode of the UE 130. The paging message is composed of eight areas, and includes a paging purpose, identifier information, and the like.

The URA_PCH state is basically the same as CELL_PCH, such as a battery saving function using a DRX parameter, but the process is performed in units of URA (bundle of cells) rather than the cell to which the UE 130 belongs. Although there is a CELL_PCH state that is responsible for similar functions, the URA_PCH state is a state necessary to prepare for when the UE 130 moves at high speed. When the UE 130 passes a large number of cells in a short time, too many cell updates occur in a short time, which may reduce network efficiency. Determining the size of the URA according to the moving speed of the UE 130 is an important problem in determining performance. The difference from the CELL_PCH state is that uplink is not supported. Therefore, data must be transmitted through the CELL_PCH state in order to perform a WCDMA network update.

 When the RRC connection is connected, resources are allocated from the UTRAN 120 and u-RNTI serving as an identifier in the UTRAN 120 is granted. As with other communication protocols, logical connections for each layer occur. The logical connection relationship for each layer is as follows.

RL (Radio Link) is a link created in the physical layer. To be exact, it may be said that the connection between the UE 130 and the Node-B 122 of the UTRAN 120. One RL is a connection between one Node-B 122 and one UE 130. However, the Node-B 122 maintains connection with a large number of UEs 130, and there is only one RF (Radio Frequency) carrier output from the Node-B 122 of the WCDMA network in the FDD mode. Thus many RLs are included together in one RF carrier. Numerous RLs are divided into channelization codes and scrambling codes, respectively, and are connected to each UE 130. RLS (Radio Link Set) is a bundle of RLs. Connections from one Node-B 122 may be viewed as one RLS.

RB (Radio Bearer) is a connection used in the AS stage. It is used for both user information and signal transmission. Especially, RB used for signal transmission is called Signaling Radio Bearer (SRB). SRB includes physical channel connection, transport channel connection, logical channel connection, and RLC channel connection. As they are connected, the RRC connection is connected. The SRB is a connection between the UE 130 and the RNC 121 except for the physical channel connection.

RAB (Radio Access Bearer) is a concept higher than that of RB, that is, NAS related. RAB, which is formed based on QoS at the request of SGSN, is focused on transmitting user information, unlike SRB that sends and receives signal information. RAB consists of Iu-bearer and RB.

 The PDP context is one notch higher than RAB. User data using the PS domain is connected based on QoS from the UE to the GGSN. This connection consists of the CN bearer and the RAB.

4 is a flowchart showing a procedure of an RRC operation according to an embodiment of the present invention.

The UE 130 first determines whether to include the RACH measurement when transmitting the Cell Update message (S110). If it is determined that the RACH measurement is not included in the Cell Update message, since the size of the Cell Update message does not exceed 166 bits, the Cell Update message is directly transmitted to the RLC TM SAP (S120). If the Cell Update message includes RACH Measurement, the size of the Cell Update message including the RACH Measurement for N cells is calculated according to the number N of cells to be reported in SIB11 of 3GPP TS25.331 (S130). . If the size of the calculated Cell Update message is determined (S140) or less than the SDU division allowable size (for example, 166 bits), the Cell Update message is transmitted to the RLC TM SAP (S120), and the size of the calculated Cell Update message is SDU. If the division allowance is exceeded, N is decreased by 1 (S150). The size of the Cell Update message including the RACH measurement corresponding to the reduced N is recalculated (S130). N is reduced so that the calculated Cell Update message size is smaller than the SDU splitting allowable size. If the Cell Update message size is smaller than the SDU splitting allowable size, the cell Update message is changed and transmitted to the RLC TM SAP (S130).

While the above methods have been described through specific embodiments, the methods may also be implemented as computer readable code on a computer readable recording medium. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like, which are also implemented in the form of carrier waves (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs, codes, and code segments for implementing the above embodiments can be easily deduced by programmers of the present invention.

In addition, while the present invention has been described in connection with some embodiments, it is to be understood that various modifications and changes can be made without departing from the spirit and scope of the invention as will be understood by those skilled in the art. You will need to know It is also contemplated that such variations and modifications are within the scope of the claims appended hereto.

1 is a flowchart showing an RRC state transition process from a CELL_DCH state to a Cell_PCH state.

2 is a flowchart showing a call processing procedure in a Cell_PCH or URA_PCH state.

Figure 3 is a block diagram showing the configuration of a mobile communication system according to an embodiment of the present invention.

4 is a flowchart showing a procedure of an RRC operation according to an embodiment of the present invention.

Claims (7)

In the cell update message active control method of the present invention, a) determining whether to include a RACH measurement when transmitting a Cell Update message; b) calculating the size of the Cell Update message if the Cell Update message includes the RACH Measurement; c) transmitting the Cell Update message when the size of the Cell Update message is less than or equal to the SDU division allowable size and reducing the number of cells when the SDU division allowance is exceeded; And d) repeating step c) by calculating the size of the Cell Update message corresponding to the reduced number of cells; Cell update message active control method comprising a. The method of claim 1, And transmitting the Cell Update message if the Cell Update message does not include the RACH Measurement. The method of claim 2, And if the reduced number of cells is zero, transmitting the Cell Update message without including the RACH Measurement. The method of claim 3, And the SDU partitioning allowable size is 166 bits. As a mobile communication system, When the Cell Update message is transmitted, it is determined whether the RACH measurement is included, and when the Cell Update message includes the RACH measurement, the size of the Cell Update message is calculated, and when the size of the Cell Update message is smaller than the SDU division allowable size, the Cell is determined. A mobile communication for transmitting an Update message, reducing the number of cells when the SDU splitting allowance is exceeded, and controlling the Cell Update message by calculating the size of the Cell Update message corresponding to the reduced number of cells. system. The method of claim 5, And when the reduced number of cells is zero, transmitting the Cell Update message without including the RACH measurement. The method of claim 6, And the SDU partitioning allowable size is 166 bits.

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