KR20050053871A - Method for measuring neighbor access environment of mobile communication for handoff of connected mobile between asynchronous mobile communication and synchronous mobile communication mobile - Google Patents

Abstract

According to the present invention, when detecting a handoff event from a WCDMA network to a CDMA network, the base station controller notifies the mobile station of the radio environment measurement event, and the CDMA frequency band information to be measured in the DT message of the RANAP protocol of the WCDMA standard defined for the Iu interface. And the CDMA standard surrounding frequency measurement request message indicating the measurement method and transmitting to the switching center, and the switching station converts the received DT message into the RP-DATA message among the WCDMA standard SMS messages defined as transmission messages between the switching station and the mobile station. Send it to the mobile station. Thereafter, the exchange receives the RP-DATA message including the ambient frequency measurement response message from the mobile station, converts the received RP-DATA message into a DT message, and transmits it. The base station controller measures the ambient frequency, which is a MAHO message indicating the radio environment measurement. The control message is included in the DT message of the RANAP protocol and transmitted to the switching center. The exchange converts the received DT message into an RP-DATA message and transmits it to the mobile station, receives the RP-DATA message including the surrounding frequency measurement report message from the mobile station, converts the DT message into a DT message, and transmits the received message to the base station controller. The CDMA cell to be handed off is determined through a peripheral frequency measurement report message, and a handoff is requested to the switching center.

Description

Method for measuring neighbor access environment of mobile communication for handoff of connected mobile between asynchronous mobile communication and synchronous mobile communication mobile}

The present invention relates to a hand-off from an asynchronous mobile communication network to a synchronous mobile communication network. In particular, WCDMA using a CDMA Mobile Assisted Handoff (MAHO) algorithm in a WCDMA network during handoff from a WCDMA network to a CDMA network. The present invention relates to a method for enabling a mobile station in a network to measure radio resources for a CDMA cell.

In general, mobile communication networks such as WCDMA networks and CDMA networks support handoff technology to ensure mobility of mobile stations. Handoff is a technique of connecting a communication channel of a mobile station moving from a current cell to a next cell to a next cell from a current cell. This handoff is a control channel signal of a current cell received at a mobile station located at a boundary between the current cell and the next cell. Occurs when strength is sufficiently weak

In the wireless mobile communication environment, the mobile station measures and reports the signal strength of the control channel received at every set cycle time to monitor a situation in which the control channel strength of the current cell is sufficiently weakened (that is, a handoff event). Then, the mobile communication network determines whether the control channel strength of the current cell is sufficiently weakened based on the measurement result transmitted from the mobile station, and if it is sufficiently weak, it instructs wireless environment measurement on the neighboring cell for handoff.

In the case of a WCDMA network, inter-frequency radio environment measurement is performed using a specific transmission mode called a compression mode defined by the Universal Mobile Telecommunication System (UMTS) of 3F TS25.212, and a Radio Resource Control (RRC) protocol. The message is made between the UTRAN (UMTS Terrestrial Radio Access Network) and the mobile station. Briefly describing the process, the mobile station reports the signal strength of the measured control channel to the UTRAN as a Radio Resource Control (RRC) / Measurement Report message, and the UTRAN determines that the received message is a received message. The RRC / Measurement Control message is sent to the mobile station to determine what is the next cell to move. Accordingly, the mobile station measures the radio environment for the neighboring CDMA cell according to the radio environment measurement information set, and informs the UTRAN of the cell with the largest received signal strength.

In the case of CDMA networks, radio environment measurements typically follow the MAHO algorithm. The radio frequency measurement according to the MAHO algorithm measures a downlink signal transmitted from a neighbor base station controller of a cell in which a mobile station is currently located at the request of a base station located in a current cell, reports the result, and reports the cell to be handed off by the base station controller of the current cell. (I.e., base station) can be determined, this MAHO algorithm is already standardized.

Radio environment measurement process according to a more detailed MAHO algorithm is shown in FIG. As shown in FIG. 1, the mobile station 1 reports a measurement result of the received signal strength of the current cell, and exchanges a message directly with the mobile station 1 at the base station controller (BSC) 2 that has received it. Is achieved.

At this time, the MAHO message for radio environment measurement exchanged between the mobile station 1 and the BSC (2) is according to the standard, such as the Candidate Frequency Search Request Message (CFSRQM), Candidate Frequency Measurement Response Message (CFSRSM) Search Response Message (CFSCNM), Candidate Frequency Search Control Message (CFSCNM), and Candidate Frequency Search Report Message (CFSRPM).

The CFSRQM is a signal transmitted from the BSC 2 to the mobile station 1, and includes measurement information for measuring a pilot signal transmitted from a base station of each CDMA cell, as well as band information of a target frequency to be measured. This message is provided. The CFSRSM is a signal transmitted from the mobile station 1 to the BSC 2 and is a response message of the CFSRQM which reports that the measurement preparation is completed according to the information of the CFSRQM. The CFSCNM is a signal transmitted from the BSC 2 to the mobile station 1, and is a message instructing to perform measurement preparation set according to the CFSRQM. The CFSRPM is a signal transmitted from the mobile station 1 to the BSC 2, and is a response message of the CFSRPM which reports the result of measuring the radio environment for the neighboring CDMA cells according to the CFSCNM to the BSC 2.

When the BSC 2 receives the CFSRPM from the mobile station 1, the BSC 2 determines the next cell to hand off through the received CFSRPM message.

On the other hand, in the case of the domestic WCDMA network, which is a pilot service level, since the construction area of the WCDMA network is local, the WCDMA network should provide a handoff service to a user who has left the WCDMA network and enters the CDMA network. It must have a process of measuring radio environment for CDMA cell at the time of occurrence.

However, when the wireless environment for the CDMA cell is measured in the WCDMA network when the handoff occurs from the WCDMA network to the CDMA network, the radio environment for the CDMA cell cannot be measured.

This is because the radio environment measurement in the WCDMA network described above is a radio environment measurement for cells in the same network. Therefore, it cannot accept parameters for radio environment measurement for a CDMA cell having a different radio access specification and use frequency from the WCDMA network. As a result, the radio environment of other frequency bands cannot be measured.

Accordingly, an object of the present invention is to solve a conventional problem and to instruct and receive a radio environment measurement for a CDMA cell from a mobile station in a WCDMA network.

In order to achieve the above technical problem, the present invention is characterized by applying the MAHO algorithm used in the CDMA network to the WCDMA network, and measuring the radio environment for the CDMA cell on the WCDMA radio access standard according to the MAHO algorithm.

Therefore, according to an aspect of the present invention, when a base station controller of a WCDMA network determines a handoff event through a radio environment for a current cell periodically received from a mobile station, the base station controller wirelessly transmits to the mobile station. A first step of informing an environmental measurement event, and the base station controller measures the CDMA standard peripheral frequency information informing the CDMA frequency band information to be measured and the measurement method in a DT (Direct Transfer) message of the RANAP protocol of the WCDMA standard defined for the lu interface. A second step of including the request message to the switching center, and the switching station converts the received DT message of the RANAP protocol into an RP-DATA message among SMS messages of the WCDMA standard defined as a transmission message between the switching station and the mobile station; A third step of transmitting to the mobile station; Receiving the RP-DATA message including an ambient frequency response message from the mobile station, converting the received RP-DATA message into a DT message of a RANAP protocol and transmitting the received RP-DATA message to the base station controller; The base station controller receiving the step 5 includes transmitting a peripheral frequency measurement control message, which is one of the MAHO messages indicating radio environment measurement, to the switching station by including the DT message of the RANAP protocol, and the switching station receives the received RANAP. Converting the DT message of the protocol into the RP-DATA message and transmitting the RP-DATA message to the mobile station; A seventh step of converting the DT message of the RANAP protocol and transmitting the same to the base station controller; And an eighth step of determining, by the controller, the CDMA cell to be handed off through the received peripheral frequency measurement report message, and requesting handoff to the switching center. A wireless environment measurement method for a synchronous mobile communication network in a mobile communication network is provided.

Hereinafter, with reference to the accompanying drawings will be described a method of protection in an asynchronous mobile communication network for wireless environment measurement according to an embodiment of the present invention.

Since radio environment measurement using MAHO algorithm of CDMA standard is performed by message exchange between mobile station and BSC, wireless interface between mobile station and RNC (base station controller) should be used to apply MAHO algorithm to WCDMA network.

However, in the WCDMA standard, the Iu air interface is defined between the RNC and the MSC (exchange station), the Iub air interface is not defined between the RNS and the RNC, and the air interface between the mobile station and the UTRAN is defined by RRC (Radio Resource Control). There is no suitable medium for performing the MAHO algorithm of the CDMA standard.

The present invention uses the message path of the mobile station → MSC → RNC and the message path of the RNC → MSC → mobile station as a message transfer path between the mobile station and the UTRAN to solve this technical difficulty. In this case, since the message path between the mobile station ↔ MSC does not have a wireless interface specified in the WCDMA standard, it uses an SMS message which is a NAS (Non Access Stratum) used in a wireless mobile communication network, and the message path between the RNC↔UTRAN uses an Iu air interface. .

The present invention uses the RP-DATA message exchanged directly between the mobile station and the MSC in using the SMS message of the NAS. The specification of the RP-DATA message is known from 3GPP TS 24.011. As known from the 3GPP TS 24.011, the RP-DATA message is a message transmitted directly between the mobile station and the MSC.

In addition, the present invention uses a Direct Transfer (DT) message conforming to the Radio Access Network Application Part (RANAP) protocol which is directly exchanged between the RNC and the MSC in using the Iu air interface. According to the WCDMA specification, DT messages are used for direct exchange between the MSC and the RNC.

Therefore, the present invention uses the RANAP / DT message between the MSC and the RNC interval described above, and the NAS / SMS message between the MSC and the mobile station, the message path of the mobile station → MSC → RNC and the message path of the RNC → MSC → mobile station This allows a WCDMA standard message to be exchanged between the mobile station and the RNC.

Here, when a RANAP / DT message is sent from the RNC to the MSC, the MSC does not know that the received RANAP / DT message should be delivered to the mobile station. In addition, even when the NAS / SMS message is transmitted from the mobile station to the MSC, the MSC does not know that the received NAS / SMS message should be transmitted to the RNC.

The present invention addresses undefined (i.e. not used) fields among fields of a RANAP / DT message to resolve the unrecognized relay of the MSC and to transmit the MAHO type messages CFSRQM, CFSRSM, CFSCNM and CFSRPM to the corresponding destination. The MAHO message is recorded and transmitted in an undefined field among fields of a NAS / SMS message.

The undefined field of the RANAP / DT message to be used by the present invention is a SAC area of a Service Area Identifier (SAI) field, and the undefined field of a NAS / SMS message is a reserved area of an Information Element Identifier (IEI) field. to be. As a result, the present invention records the MAHO message in the SAC area in the SAI field of the NAS / SMS message and the MAHO message in the spare area of the IEI field.

Here, it is preferable to record a code indicating whether or not a MAHO message is recorded in the SAI field and the IEI field (hereinafter referred to as a "status code"), so that the MSC can easily grasp the transmission path.

Hereinafter, with reference to FIG. 2, a description will be given of a security method in an asynchronous mobile communication network for wireless environment measurement according to an embodiment of the present invention. 2 is a flowchart of a mah method in an asynchronous mobile communication network for measuring a wireless environment according to an embodiment of the present invention.

First, a mobile station applied to the present invention is a dual mode mobile communication terminal having a WCDMA module for processing a mobile communication signal of WCDMA standard and a CDMA module for processing a mobile communication signal of CDMA standard.

The mobile station 10 that is in a call over the WCDMA network periodically measures the received signal strength of the current cell and reports it to the RNC 20 in an RRC / Measurement Report message (S201).

Then, the RNC 20 determines whether the handoff is performed through the received RRC / Measurement Report message. If the received signal strength of the current cell becomes weak enough, the RNC 20 instructs the mobile station 10 to measure the radio environment for the neighbor CDMA cell. The RRC / Measurement Control message is transmitted (S202).

  Simultaneously with the process (S202), the RNC 20 generates a RANAP / DT message including CFSRQM in the SAC area and transmits the RANAP / DT message to the MSC 30 (S203). At this time, the SAI field including the SAC region includes a status code indicating that the CFSRQM message is included.

Upon receipt of the RANAP / DT message, the MSC 30 checks the status code of the SAI field of the RANAP / DT message to determine whether the CFSRQM message is included, indicating that the status code of the SAI field does not include the CFSRQM message. It determines itself as the destination of the message, processes itself, and if it indicates that the status code of the SAI field includes CFSRQM, it determines that the message is to be transmitted to the mobile station 10 (S204).

If the MSC 30 determines that the message is to be transmitted to the mobile station 10, the MSC 30 converts the RANAP / DT message into a NAS / SMS message, stores the CFSRQM in the reserved area of the IEI field (S205), and transmits the message to the mobile station 10. (S206). At this time, the IEI field includes a status code indicating that the CFSRQM is included.

When the WCDMA module of the mobile station 10 receives the NAS / SMS message including the CFSRQM from the MSC 30, the WCDMA module checks the IEI field of the NAS / SMS message and knows that the CFSRQM is included. The mobile station then activates the CDMA module and passes the CFSRQM to the CDMA module. Upon receiving the CFSRQM, the CDMA module checks the frequency band information of the CDMA cell to be measured and other basic information for measuring the radio environment, and prepares the measurement accordingly.

On the other hand, upon receiving the CFSRQM, the WCDMA module of the mobile station 10 includes the CFSRSM, which is the response message of the CFSRQM, in the reserved area of the NAS / SMS message and transmits it to the MSC 30 (S207). In this case, the IEI field of the NAS / SMS message also includes a status code indicating that CFSRSM is included.

When the MSC 30 receives the NAS / SMS message from the mobile station 10, the MSC 30 checks the IEI field to determine that the destination is the RNC 20 (S208), and converts it into a RANAP / DT message including the CFSRSM (S209). Transmission to the RNC 20 (S210).

The RNC 30 knows that the mobile station 10 has received a message transmitted by the mobile station 10 in the RANAP / DT message including the CFSRSM received from the MSC 30, and accordingly RANAP / including the CFSRCNM indicating the radio environment measurement. The DT message is transmitted to the MSC 30 (S211). Accordingly, the MSC 30 checks the status code of the SAI field of the RANAP / DT message including the CFSRCNM (S212), converts it into a NAS / SMS message including the CFSRCNM (S213), and then transmits it to the mobile station 10. (S214).

When the mobile station 10 receives the NAS / SMS message including the CFSRCNM, the mobile station 10 drives the CDMA module to measure the radio environment for the neighboring CDMA cells according to the information included in the CFSRQM. When the mobile station 10 measures the radio environment for the neighboring CDMA cell, the result is included in the CFSRPM, which is the response of the CFSRCNM, and a NAS / SMS message including the CFSRPM is generated and transmitted to the MSC 30 (S215).

After checking the IEI field of the NAS / SMS message (S216), the MSC (30) identifies the message to be transmitted to the RNC 20, converts the NAS / SMS message into a RANAP / DT message including CFSRPM (S217), The transmission is sent to the RNC 20 (S218). Then, the RNC 20 determines a CDMA cell to be handed off through a radio environment report on the CDMA cell measured by the mobile station, and transmits a RANAP / Relocation request message to the MSC 30 requesting handoff to the determined CDMA cell. (S219).

When the MSC 30 receives the Relocation Request message from the RNC 20, it will communicate with the CDMA switch to cause the CDMA switch to allocate a channel to the mobile station 30.

The technical spirit of the present invention has been described above with reference to the accompanying drawings, but this is by way of example only and not intended to limit the present invention. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

According to the present invention, by defining a message according to the WCDMA standard and an undefined region of a message to be used, and using a word system according to the WCDMA standard, the radio environment for a CDMA cell in a WCDMA network can be measured.

1 is a flowchart illustrating a radio environment measurement method in a general CDMA network.

2 is a flowchart illustrating a wireless environment measurement method for a synchronous mobile communication network in an asynchronous mobile communication network to support handoff of a mobile station in a call according to an embodiment of the present invention.

Claims (6)

If the base station controller of the WCDMA network determines the handoff event through the radio environment for the current cell periodically received from the mobile station, The base station controller is a first step of informing the mobile station of the radio environment measurement event; The base station controller transmits a CDMA standard peripheral frequency measurement request message indicating a CDMA frequency band information to be measured and a measurement method in a DT (Direct Transfer) message of a RANAP protocol of a WCDMA standard defined for an Iu interface, and transmits it to a switching center. Two steps; A third step of the exchange station converting the received DT message of the RANAP protocol into an RP-DATA message among WCDMA standard SMS messages defined as a transmission message between the exchange station and the mobile station and transmitting the RP-DATA message to the mobile station; Receiving, by the switching station, the RP-DATA message including the peripheral frequency measurement response message from the mobile station, converting the received RP-DATA message into a DT message of a RANAP protocol and transmitting the same to the base station controller; A fifth step of receiving, by the base station controller, the peripheral frequency measurement response message, including the peripheral frequency measurement control message, which is one of the MAHO messages indicating the radio environment measurement, in a DT message of the RANAP protocol and transmitting it to the switching center; A sixth step of the switching station converting the received DT message of the RANAP protocol into an RP-DATA message and transmitting the same to the mobile station; When the switching center receives the RP-DATA message including the neighboring frequency measurement report message from the mobile station, converting the received RP-DATA message into a DT message of the RANAP protocol and transmitting it to the base station controller; And And the base station controller determines an CDMA cell to be handed off through the received peripheral frequency measurement report message, and requests handoff to the switching center. Wireless environment measurement method for synchronous mobile communication network in asynchronous mobile communication network. The method according to claim 1, DT message of the RANAP protocol is a call characterized in that the SAI field in the SAI field, the peripheral frequency measurement request message, the peripheral frequency measurement response message, the peripheral frequency measurement control message, the peripheral frequency measurement report message is optionally included; A wireless environment measurement method for a synchronous mobile communication network in an asynchronous mobile communication network to support handoff of a mobile station. The method according to claim 2, The RP-DATA message of the SMS message may optionally include the peripheral frequency measurement request message, the peripheral frequency measurement response message, the peripheral frequency measurement control message, and the peripheral frequency measurement report message in a reserved area in an IEI field. A wireless environment measurement method for a synchronous mobile communication network in an asynchronous mobile communication network to support handoff of a mobile station in call. The method according to claim 2, In the SAC field of the DT message, a status code indicating that the MAHO message is included is recorded, and the exchange of the third and sixth steps performs a message conversion when the status code is present. A wireless environment measurement method for a synchronous mobile communication network in an asynchronous mobile communication network to support handoff of a mobile station. The method according to claim 3, In the IEI field of the RP-DATA message, a status code indicating that the MAHO message is included is recorded, and the switch of the fourth and seventh steps performs message conversion when the status code is present. A wireless environment measurement method for a synchronous mobile communication network in an asynchronous mobile communication network to support handoff of a mobile station in a call. In the processor of the WCDMA mobile network, The base station controller is a first step of informing the mobile station of the radio environment measurement event; The base station controller transmits a CDMA standard peripheral frequency measurement request message indicating a CDMA frequency band information to be measured and a measurement method in a DT (Direct Transfer) message of a RANAP protocol of a WCDMA standard defined for an Iu interface, and transmits it to a switching center. Two steps; A third step of the exchange station converting the received DT message of the RANAP protocol into an RP-DATA message among WCDMA standard SMS messages defined as a transmission message between the exchange station and the mobile station and transmitting the RP-DATA message to the mobile station; Receiving, by the switching station, the RP-DATA message including the peripheral frequency measurement response message from the mobile station, converting the received RP-DATA message into a DT message of a RANAP protocol and transmitting the same to the base station controller; A fifth step of receiving, by the base station controller, the peripheral frequency measurement response message, including the peripheral frequency measurement control message, which is one of the MAHO messages indicating the radio environment measurement, in a DT message of the RANAP protocol and transmitting it to the switching center; A sixth step of the switching station converting the received DT message of the RANAP protocol into an RP-DATA message and transmitting the same to the mobile station; When the switching center receives the RP-DATA message including the neighboring frequency measurement report message from the mobile station, converting the received RP-DATA message into a DT message of the RANAP protocol and transmitting it to the base station controller; And The base station controller determines the CDMA cell to be handed off via the received peripheral frequency measurement report message and executes an eighth step of requesting handoff to the switching center. .