CN1798419B - Method for processing layer convergence information in multimedia broadcast and multicast services - Google Patents

Abstract

According to the present invention, a method for processing layer convergence information in multimedia broadcast and multicast services is proposed, the method includes the steps: the user equipment receives and stores a system message from a radio network controller, the system message contains a frequency Layer convergence offset information; when starting a session, the radio network controller sends a multimedia broadcast and multicast service message containing the layer convergence information to the user equipment, and the layer convergence information includes the frequency information of the preferred layer at the current location and the preferred layer The cell ID of the cell; the user equipment judges whether it is on the preferred layer according to the frequency information of the preferred layer in the layer convergence information in the received multimedia broadcast and multicast service message; and if it is not on the preferred layer, then according to the received The cell identifier and the frequency layer convergence offset information in the received layer convergence information are obtained, and cell reselection is performed.

Description

Method for processing layer convergence information in multimedia broadcast and multicast services

technical field

The present invention proposes a method for processing Layer Convergence Information (LCI) in multimedia broadcast and multicast services in a mobile communication system, especially in a WCDMA (Wideband Code Division Multiple Access) mobile communication system, more specifically , a method for processing layer convergence information in multimedia broadcast and multicast services is proposed, which is used to support the improved LCI introduced by FLC (frequency layer convergence) when MBMS (multimedia broadcast and multicast services) services are provided A processing method provided for the content of (layer convergence information).

Background technique

Multimedia Broadcast and Multicast Service (hereinafter referred to as MBMS) is a new service being standardized by the Third Generation Partnership Project (hereinafter referred to as 3GPP). The MBMS service is a one-way point-to-multipoint service. The biggest feature of this service is that it can effectively utilize wireless resources and network resources.

When frequency layer convergence is used in the MBMS service, the RNC (Radio Network Controller) informs the UE of its selected PL (Preferred Layer), and lets the UE in IDLE, CELL_PCH, URA_PCH and CELL_FACH (four states of the UE) (User equipment) reselects to the PL as much as possible, and needs to send LCI to the UE.

Usually, when providing MBMS services, in order to save resources, UTRAN (Universal Terrestrial Radio Access Network) hopes to select certain PLs to preferentially provide MBMS services, not necessarily on all frequencies. In order to realize this function, the concept of frequency layer convergence is introduced in the MBMS service.

Frequency layer convergence refers to the process in which UTRAN requests UE to preferentially reselect to PL. The existing technology (TS 25.346v6.2, 0) stipulates some basic principles of frequency layer convergence, as follows:

1. In order to support frequency layer convergence, UTRAN needs to send LCI (Layer Convergence Information) related to MBMS session to UE. The LCI includes information such as the frequency information of the PL and the convergence offset of the frequency layer.

2. PL is for each MBMS service, and different PLs can be selected in different parts of the service area. The choice of PL and whether to provide MBMS service on NPL (non-preferred layer) are decided by RRM (radio resource management).

3. The frequency layer convergence offset is the same for all MBMS services in a given PL.

4. CRNC sends LCI through MCCH channel between the start and end of MBMS session. It needs to be taken into account whenever a UE in IDLE, CELL_PCH, URA_PCH and CELL_FACH states receives LCI on MCCH. Since the frequency layer convergence only affects the cell reselection process, it is not applicable to UEs in the CELL_DCH state.

Currently, it is determined that the LCI should include the service identifier, frequency information of the PL, and frequency layer convergence offset. Wherein, PL is the PL of the UE's current location.

In order to apply the frequency layer convergence offset, the UE needs to identify the cell whose current location is on the PL from the stored cell information list. The current problem is that it cannot be identified only based on the frequency information of the PL in the LCI. Let's use an example to describe it in detail.

Assumptions:

1. Base station 1 (nodeB1) is divided into three sectors: sector 1, sector 2, and sector 3. Each sector has two frequencies: f1, f2; cell 0: sector 1, f1; cell 1: sector 1, f2; cell 2: sector 2, f1; cell 3: sector 2, f2; Cell 4: sector 3, f1; cell 5: sector 3, f2. Currently, the serving cell of UE1 is cell 1 .

2. For MBMS service S1, the PL of sector 1 is f1, the PL of sector 2 is f2, and the PL of sector 3 is f1, that is, it is preferred to provide MBMS service S1 in cell 0, cell 3 and cell 4.

3. Cell 0, cell 2, cell 3, cell 4 and cell 5 are all in the measured cell information list of UE1.

The PL of the MBMS service S1 received by UE1 in the LCI is f1. UE1 judges whether to receive the MBMS service S1 according to its own situation, and if it decides to receive it, it needs to consider the information of the MBMS service S1 in the LCI. The specific process is that UE1 starts inter-frequency measurement when it finds that it is not on the PL, and then measures cell 0, cell 2 and cell 4. These three cells are all on f1, and it is impossible to judge which cell is the cell on the current location PL according to the existing information. Moreover, not all cells on f1 belong to the cell that preferentially provides MBMS service S1, for example, cell 2 does not belong, so the frequency layer convergence offset cannot be used for all cells on f1 in the cell information list.

Another problem is that the convergence offset of the frequency layer in the LCI is the same for all MBMS services in a cell, while the existing messages on the MCCH are for each service. If the frequency layer convergence offset is transmitted in one of the messages, it will be repeated many times; otherwise, a special message needs to be added to transmit the frequency layer convergence offset.

Contents of the invention

In order to overcome the above-mentioned defects, the present invention is proposed, and the purpose of the present invention is to propose a method for processing layer convergence information in multimedia broadcast and multicast services, by which method, the UE is notified of a method of giving priority to a cell that provides MBMS services at its current location, Enable UE to identify from the measurement cell information list, so as to apply frequency layer convergence offset.

In addition, the object of the present invention is to propose a method for processing layer convergence information in multimedia broadcast and multicast services, through which the traditional method of transmitting frequency layer convergence offset information is improved.

In order to achieve the above purpose, a method for processing layer convergence information in multimedia broadcast and multicast services is proposed, the method includes the steps: user equipment receives and stores a system message from a radio network controller, the system message includes Frequency layer convergence offset information; when starting a session, the radio network controller sends a multimedia broadcast and multicast service message containing the layer convergence information to the user equipment, and the layer convergence information includes the frequency information of the preferred layer and the current location preferred The cell identity of the layer cell; the user equipment judges whether it is on the preferred layer according to the frequency information of the preferred layer in the layer convergence information in the received multimedia broadcast and multicast service message; and if it is not on the preferred layer, then according to performing cell reselection based on the received cell identifier in the layer convergence information and the frequency layer convergence offset information.

Preferably, according to the present invention, the step of receiving, by the user equipment, the system message including the frequency convergence layer offset information from the radio network controller is realized through BCCH (broadcast control channel).

Preferably, according to the present invention, the system message is composed of frequency layer convergence offset information and cell selection and reselection information including cell selection and reselection parameters.

Preferably, according to the present invention, the step of performing cell reselection includes the following sub-steps: perform measurement on each cell in the cell list (including the inter-frequency cell list); calculate the R value of each measured cell; applying the frequency convergence layer offset to the corresponding cell; and selecting the cell with the largest R value from the cells as the reselected cell.

Preferably, according to the present invention, the step of the radio network controller sending the multimedia broadcast and multicast service message containing the layer convergence information to the user equipment is through the MCCH (multimedia broadcast and multicast service point-to-multipoint control channel) channel implemented.

Preferably, according to the present invention, the step of starting a session is initiated when the RNC receives a session start message from the SGSN.

Preferably, according to the present invention, when the RNC receives a session start message from the SGSN, the RNC determines the preferred layer of each area, so as to transmit the layer including the frequency information of the preferred layer and the cell identity of the preferred layer cell at the current location to the user equipment Convergence information.

Through the above method, according to the present invention, adding the cell identity of the cell that provides MBMS service preferentially at the current location in the LCI can make the UE identify the cell in the measured cell information list, so as to apply the frequency layer convergence offset.

In addition, adding a cell ID can solve the problem that the PL frequency information alone cannot be identified. Since the PL of different parts of the service area may be different, it is impossible to know the cell that preferentially provides MBMS service in the measured cell information list only by the frequency information.

In addition, according to the present invention, the frequency layer convergence offset is sent on the BCCH, the method is: adding the frequency layer convergence offset in the cell selection and reselection information of system information 3 and system information 4 . The advantages of doing this are:

1. Avoid repeatedly transmitting the frequency layer convergence offset for each MBMS service in a certain message of MCCH;

2. Avoid inventing a new message on the MCCH to transmit the frequency layer convergence offset.

Description of drawings

The above objects, advantages and features of the present invention will become apparent by referring to the following detailed description of preferred embodiments taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a sequence diagram illustrating an operation process of a method for processing layer convergence information in multimedia broadcast and multicast services according to the present invention;

Fig. 2 is a flowchart showing the operation process carried out by RNC (radio network controller) in the processing method of layer convergence information according to the present invention:

FIG. 3 is a flow chart showing an operation process performed by a UE in a method for processing layer convergence information according to the present invention.

Detailed ways

According to the present invention, since frequency layer convergence will be realized by modifying the existing cell reselection process, so first briefly introduce the relevant content of the existing cell reselection process (please refer to the specification TS 25.346 of 3GPP for the specific meaning of various parameters , V6.2.0 and TS 25.304, V6.0.0).

The UE calculates S _x according to the received power of the serving cell (frequency division multiplexing cell: S _qual , time division multiplexing cell: S _rxlev ). In the absence of HCS (Hierarchical Cell Structure), the following principles need to be obeyed:

1. If S _x >S _intrasearch , the UE does not need to perform intra-frequency measurement.

If S _x <= S _intrasearch , the UE needs to perform intra-frequency measurement.

If the S _intrasearch of the serving cell is not sent, the UE needs to perform intra-frequency measurement.

2. If S _x >S _intersearch , the UE does not need to perform inter-frequency measurement.

If S _x <= S _intersearch , the UE needs to perform inter-frequency measurement.

If the S _intersearch of the serving cell is not sent, the UE needs to perform inter-frequency measurement.

3. If S _x >S _searchRATm , the UE does not need to measure the cell whose radio access technology is "m".

If S _x <= S _searchRATm , the UE needs to measure the cell whose radio access technology is "m".

If the S _searchRATm of the serving cell is not sent, the UE needs to measure the cell of RAT "m".

UTRAN sends measurement information to UE through system information 11 and system information 12 . The measurement information includes an intra-frequency cell information list, an inter-frequency cell information list, and an inter-RAT cell information list. The cell information includes cell identifiers and cell information, and the inter-frequency cell information also includes frequency information.

The UE measures each cell in the cell list according to the measurement information, and calculates the R value of each cell. The R value is defined as:

R _s = Q _{meas, s} + Qhyst _s

R _n = Q _{meas, n} - Q offset _{s, n} - TO _n *(1-L _n )

Among them, R _s is used for the serving cell, and R _n is used for the nth neighboring cell.

In the above formula, TO _n =TEMP_OFFSET _n *W(PENALTY_TIME _n -T _n )

L _n = 0 if HCS_PRIO _n = HCS_PRIO _s

L _n = 1 if HCS_PRIO _n <> HCS_PRIO _s

W(x)＝0 for x＜0

W(x)＝1 for x＞＝0

For all the cells that meet the S principle, they are arranged according to the R value from large to small, and the cell ranked first is selected as the reselected cell.

The S-principle is:

FDD cell s: S _rxlev > 0 and S _qual > 0

For TDD cell s: S _rxlev >0

For GSM (Global System for Mobile Communications) cell s: S _rxlev > 0

in:

S _qual = Q _qualmeas -Q _qualmin

S _rxlev =Q _rxlevmeas -Q _rxlevmin -P _compensation

In order to support frequency layer convergence in MBMS services, the following functions need to be added to cell reselection:

1. When the MBMS session starts, UTRAN selects PL and sends it to UE through MCCH. When the UE finds that it is not on the PL after receiving the LCI, it will ignore the S _intersearch parameter and perform inter-frequency measurement.

2. In order to allow UEs that are not on the PL to preferentially reselect to the PL, it is necessary to apply the frequency layer convergence offset to the calculation of the R value, and how to apply it is still to be discussed.

A method of processing layer convergence information in a mobile communication system according to the present invention will be described below with reference to the accompanying drawings.

Through the processing method of the present invention, the UE can be notified of the cell in which the MBMS service is preferentially provided at the current location, so that the UE can identify it from the measured cell information list, so as to apply the convergence offset of the frequency layer. Through the processing method of the invention, an improvement of the method of conveying the frequency layer convergence offset is also given.

According to the present invention, in order to inform the UE of the cell that preferentially provides the MBMS service at the current location, the cell identifier of the cell can be added to the LCI. The measured cell information stored by the UE includes the cell ID, and the UE can find the corresponding cell in the cell information list according to the cell ID, so as to apply the frequency layer convergence offset.

In addition, because the frequency layer convergence offset is the same for all MBMS services in a cell, and the frequency layer convergence offset changes infrequently, the frequency layer convergence offset can be transmitted on the BCCH. The cell selection and reselection information in system information 3 and system information 4 includes parameters of cell selection and reselection, and the frequency layer convergence offset can be added to it.

First, an operation procedure of a method for processing layer convergence information in a mobile communication system according to the present invention will be described with reference to FIG. 1 .

Step 101 - RNC sends system message 3 and system message 4 to UE through BCCH channel. System information 3 and system information 4 contain cell selection and reselection information, and frequency layer convergence offset is added to this information.

After receiving the frequency layer convergence offset, the UE saves it.

Step 102 - When the session of the MBMS service starts, the SGSN sends a "session start" message to the RNC.

After receiving the "session start" message, the RNC determines the PL in each area and sets timer 1. Timer 1 is the time reserved for UE to reselect to PL

Step 103 - RNC sends MBMS service information to UE through MCCH channel, which includes frequency information of PL and cell identity of PL cell at current location.

After receiving the LCI, the UE judges whether to receive the MBMS service according to its own situation. If you decide to receive it, you need to consider the information of this MBMS service in the LCI. The specific operation is that after receiving the frequency information of the PL, the UE judges whether it is on the PL. If not, ignore the S _intersearch parameter and perform inter-frequency measurements. When calculating the R value of each measurement cell, the frequency layer convergence offset is applied to the corresponding cell according to the cell identity of the PL cell in the current area. Then arrange the R values of each cell in descending order, and select the cell that ranks first as the reselected cell.

After the timer 1 at the RNC side expires, it starts counting in the cells that need to be counted.

Step 104 - RNC sends access information to UE through MCCH channel, and starts counting process.

Next, the counting process will start. The following processes are clearly stipulated in the 3GPP agreement, and will not be repeated here.

The operation process performed by the RNC in the method for processing layer convergence information according to the present invention will be described below with reference to FIG. 2 .

Step 201-RNC receives a message from SGSN;

Step 202 - judging whether a "session start" message from the SGSN is received;

Step 203 - if the "session start" message is received, the RNC determines the PLs in each area, that is, the cells that provide MBMS services preferentially;

Step 204 - set timer 1, start timing, and start sending the "MBMS service information" of the service on the MCCH, which includes the PL of the MBMS service and the cell identity of the current location PL cell;

Step 205—judging whether timer 1 is overtime;

Step 206 - if the timer 1 is overtime, start sending the "access message" of the service on the MCCH;

The following will refer to FIG. 3 for a flow chart of the operation process performed by the UE in the layer convergence information processing method according to the present invention.

Step 301-UE receives a message;

Step 302 - judging whether "system message 3" or "system message 4" is received;

Step 303 - If "system message 3" or "system message 4" is received, determine whether it contains frequency layer convergence offset;

Step 304 - if it contains a frequency layer convergence offset, store the frequency layer convergence offset;

Step 305 - storing other information in the message;

Step 306 - receiving MBMS service information, and judging whether there is a service in which the UE has joined;

Step 307 - If the service information of the MBMS service that the UE has joined is received, determine whether it contains LCI (the LCI contains the frequency information of the PL and the cell identity of the PL cell at the current location);

Step 308 - if the LCI is included, the UE judges whether it is on the PL;

Step 309—If the UE is not on the PL, it needs to perform inter-frequency measurement, calculate the R value of each cell, and make a cell reselection decision. When calculating the R value of each cell, it is necessary to apply an offset to the R value of the cell according to the cell identity of the PL cell at the current location;

Step 310 - judging whether cell reselection is required;

Step 311 - If cell reselection is required, the UE will perform cell reselection;

Step 312 - When the UE receives the "MBMS service access information" on the MCCH, it needs to determine whether there is access information of the MBMS service that the UE has joined;

Step 313 - If the access information of the MBMS service that the UE has joined is received, the UE needs to access it.

Although the present invention has been illustrated above in conjunction with preferred embodiments of the present invention, those skilled in the art will appreciate that various modifications, substitutions and changes can be made to the present invention without departing from the spirit and scope of the present invention. . Accordingly, the invention should not be limited by the above-described embodiments, but by the appended claims and their equivalents.

Claims (7)

1. A method for processing layer convergence information in multimedia broadcast and multicast services, said method comprising steps: The user equipment receives and stores a system message from the radio network controller, where the system message includes frequency layer convergence offset information; When starting a session, the radio network controller sends a multimedia broadcast and multicast service message including the layer convergence information to the user equipment, and the layer convergence information includes the frequency information of the preferred layer at the current location and the cell identity of the preferred layer cell; The user equipment judges whether it is on the preferred layer according to the frequency information of the preferred layer in the layer convergence information in the received multimedia broadcast and multicast service message; and If not on the preferred layer, perform cell reselection according to the received cell identifier in the layer convergence information and the frequency layer convergence offset information. 2. The method according to claim 1, wherein the step of receiving, by the user equipment, the system message containing the frequency convergence layer offset information from the radio network controller is realized by broadcasting a control channel. 3. The method according to claim 1 or 2, wherein the system message is composed of frequency layer convergence offset information and cell selection and reselection information including cell selection and reselection parameters. 4. The method according to claim 1, characterized in that: the step of performing cell reselection comprises the following sub-steps: performing measurements on cells in a cell list including an inter-frequency cell list; Calculate the R value of each measurement plot; applying a frequency convergence layer offset to the corresponding cell according to the cell identity of the preferred layer cell in the current area; and Select the cell with the largest R value from each cell as the reselected cell, Among them, the R value is defined as: R _s = Q _{meas, s} + Qhyst _s , R _n = Q _{meas, n} - Q offset _{s, n} - TO _n *(1-L _n ), Among them, R _s is used for the serving cell, R _n is used for the nth neighboring cell, In the above formula, TO _n =TEMP_OFFSET _n *W(PENALTY_TIME _n −T _n ), and if HCS_PRIO _n =HCS_PRIO _s then L _n =0, and if HCS_PRIO _n ≠HCS_PRIO _s , then L _n =1; for x< 0, W(x)=0, and for x>=0, W(x)=1, Wherein Q _{meas, s} represents the signal-to-noise ratio measurement quantity of the serving cell; Q _{meas, n} represents the signal-to-noise ratio measurement of adjacent cells; Qhyst _s represents the hysteresis parameter of cell reselection; Qoffset _{s, n} represents the offset between the serving cell and the neighboring cell; R _s represents the cell grade standard of the serving cell; R _n represents the cell grade standard of the neighboring cell; L _n represents whether the priorities of the adjacent cell and the serving cell are the same; TO _n represents a temporary offset value determined according to the priority and time of adjacent cells; TEMP_OFFSET _n represents the temporary adjacent cell offset; PENALTY_TIME _n indicates the time to indicate that the adjacent cell applies the temporary offset value; T _n represents the timer of the neighboring cell; HCS_PRIO _n indicates the priority of the hierarchical cell structure of neighboring cells; and HCS_PRIO _s indicate the priorities of the hierarchical cell structure of the serving cell. 5. The method according to claim 1, characterized in that: the step of the radio network controller sending the multimedia broadcast and multicast service message comprising the layer convergence information to the user equipment is through the multimedia broadcast and multicast service point-to-multiple Point control channel to perform. 6. The method according to claim 1, wherein the step of starting a session is started when the radio network controller receives a session start message from the serving GPRS support node. 7. The method according to claim 6, characterized in that: when the radio network controller receives the session start message from the serving general packet radio service support node, the radio network controller determines the preferred layer of each region, so as to provide The user equipment transmits layer convergence information including the frequency information of the preferred layer at the current location and the cell identity of the cell of the preferred layer.

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