CN1249943C - A compress mode measurement parameter configuration method - Google Patents

Abstract

A method for configuring compressed mode measurement parameters, which relates to a method for configuring compressed mode parameters required for a UE in a WCDMA system to measure another mobile communication system, including a parameter acquisition process and a parameter configuration process; the parameter acquisition process is completed The timing information of the GSM cell is obtained from the measurement report of the user equipment; the parameter configuration process completes the parameter configuration of the user equipment that needs compressed mode parameter configuration according to the obtained timing information of the GSM cell. By adopting the method of the present invention, appropriate compressed mode parameters can be assigned to the UE, and the UE can accurately decode the SCH in the compressed mode frame defined by these compressed mode parameters, so as to ensure that the measurement performance required by the system is achieved, and at the same time, the The number of compressed mode frames required is reduced, the system transmission power is reduced, and the system capacity is improved.

Description

A Configuration Method of Compressed Mode Measurement Parameters

technical field

The present invention relates to UE (User Equipment, user equipment) in WCDMA (Wideband Code Division Multiple Access, wideband code division multiple access) system to another mobile communication system, especially GSM (Global System for Mobile Communications, Global Mobile communication system) system, a method for configuring compressed mode parameters required for measurement.

Background technique

As one of the representatives of the third-generation mobile communication technology, WCDMA technology is being increasingly widely used. But the mobile communication system adopting the second generation mobile communication technology (mainly GSM technology) still occupies the main position in the market. For cost considerations, WCDMA mobile communication systems will be mixed with GSM mobile communication systems in the foreseeable future. In order to ensure seamless coverage of user services, it is necessary to realize handover from the WCDMA system to the GSM system or from the GSM system to the WCDMA system.

Considering the handover from the WCDMA system to the GSM system, in order to ensure the success rate of the handover, the UE must do: 1, be able to measure the RSSI (Received Signal Strength Indicator) of the target GSM cell; 2, be able to Synchronize with the target cell. This requires the UE to measure the BCCH (Broadcast Control Channel, broadcast control channel) carrier frequency of the GSM cell, and to synchronize the SCH (Synchronization Channel, synchronization channel) of the GSM cell. On the other hand, under normal circumstances, a UE with only one transceiver that is performing services (especially voice services) in a WCDMA system will receive and transmit at all times, that is to say, under normal circumstances, the UE will not have the opportunity to perform a call to the GSM cell. Measure and sync. To solve this problem, the WCDMA system specification points out that the UE in the dedicated traffic channel state can enter the compressed mode state. In this state, the UE will stop receiving or transmitting in the WCDMA cell in certain time slots in certain frames. And use these times to measure and synchronize the GSM cell. For the description of the compressed mode, please refer to 3GPP specification 25.212. In order to ensure the transmission quality of the remaining time slots, frames using compressed mode will be transmitted with higher power than normal frames. Figure 1 shows the structure of a compressed mode frame.

The protocol specifies three TGPS (transmission gap pattern sequence) for GSM measurement, which are used for three different measurements of "GSM Carrier RSSI", "Initial BSIC Identification" and "BSIC Re-confirmation". Purpose. Each TGPS has different parameters describing the time when the compressed mode frame appears, which is set by the RNC (Radio Network Controller, radio network controller) and sent to the UE. Among them, "GSM Carrier RSSI TGPS" is used to measure the BCCH carrier frequency RSSI of the GSM cell, "Initial BSIC Identification TGPS" is used for the UE to decode the SCH of the GSM cell for the first time without knowing the timing information of the GSM cell, and "BSIC Re-confirmationTGPS" is used to perform subsequent decoding of the SCH under the condition that the first decoding of the SCH of the GSM cell has been completed. Simply put, "BSIC Re-confirmation TGPS" is used to keep the GSM cell in sync, so it needs to be done periodically.

Since GSM adopts TDMA (Time Division Multiple Access) technology, SCH channels are discretely distributed on the time axis (as shown in Figure 2), so the "BSIC Re The measurement gaps (Gaps) generated by -confirmation TGPS" compressed mode parameters may not necessarily coincide with the occurrence time of the GSM SCH channel. In this case, if good measurement performance is required, enough compressed mode frames should be allocated to the UE within a unit time, so that the UE can have enough opportunities to complete the decoding of the SCH within a certain period of time. However, as mentioned above, under the condition of a large number of UEs, the allocation of too many compressed mode frames will significantly increase the power transmission level of the WCDMA cell, which will not only increase the interference but also reduce the capacity of the cell. The US patent "Reducing interference in inter-frequency measurement" (application number: 20010022782) configures appropriate compressed mode parameters for different UEs so that the compressed mode frames of different UEs will not overlap in time to reduce power levels and interference . Obviously, this method is only to make the frame distribution of the compressed mode as uniform as possible and reduce the highest possible instantaneous power, but it has no effect on the increase of the average power.

Contents of the invention

The present invention proposes a method for configuring the compressed mode parameters required for the UE in the WCDMA system to perform GSM inter-system measurement. The method can ensure that the allocated compressed mode frames can be synchronized with the appearance time of the SCH channel of the GSM cell, that is, The UE can definitely complete the decoding of the SCH channel of the GSM cell in the allocated compressed mode frame, thus reducing the number of required compressed mode frames while ensuring high measurement performance and reducing the total transmission power of the system.

Technical scheme of the present invention is:

A compressed mode measurement parameter configuration method, including a parameter acquisition process and a parameter configuration process; the parameter acquisition process is to complete the acquisition of the timing information of the GSM cell from the measurement report of the user equipment; the parameter configuration process is based on the obtained GSM cell Timing information to complete the parameter configuration of the user equipment that needs to be configured with compressed mode parameters.

The process of obtaining the timing information of the GSM cell from the measurement report of the user equipment in the above solution includes:

2.1 The radio network controller (RNC) orders the user equipment (UE) to measure the timing information of the (BCCH51) multiframe of the GSM adjacent cell including the GSM broadcast channel;

2.2 The UE uses the measurement result as the time between the start time of the (BCC51) multiframe containing the GSM broadcast channel of the GSM neighboring cell and the start time of the frame with the system frame number 0 (SFN=0) in the cell where the user equipment (UE) resides Report to RNC in the form of difference;

2.3 The RNC converts the measurement result reported by the UE into the difference between the start time of the (BCCH51) multiframe of the GSM broadcast channel (BCCH51) of the GSM adjacent cell and the frame number counter RFN of the radio network controller;

2.4 calculate according to above-mentioned difference value in one RNC cycle, corresponding corresponding GSM sub-district each synchronous channel (SCH) frame start moment and the RNC frame number counter value of radio network controller between the frame start moment of 0 (RFN=0) The difference value, and determine the RNC frame number counter value (RFN) of the frame that can be used for GSM measurement according to this difference value.

The conversion process described in 2.3 above includes: first, the measurement results are converted from the start time of the multiframe (BCCH51) of the GSM adjacent cell containing the GSM broadcast channel to the multiframe with the system frame number 0 (SFN=0) in the cell where the UE resides. The difference between the start time of the frame" is converted into "the start time of the (BCCH51) multiframe of the GSM adjacent cell containing the GSM broadcast channel and the NodeB frame number counter value in the NodeB of the cell where the user equipment (UE) resides is 0 ( BFN=0) between the difference between the start time of the frame"; then converted to "the (BCCH51) multiframe start time of the GSM adjacent cell that includes the GSM broadcast channel and the user equipment (UE) camped on radio network controller The difference between the start times of the frames for which the RNC frame number counter value is 0 (RFN=0)".

The process of configuring the parameters of the user equipment includes: according to "the starting time of the multiframe containing the GSM broadcast channel of the GSM adjacent cell and the starting time of the frame whose RNC frame number counter value of the radio network controller where the user equipment resides is 0 The difference between "calculate the RNC frame number counter value of the frames that can be used for GSM measurement, and configure these frames as compressed mode frames; then convert the compressed mode parameter settings represented by the RNC frame number counter value into connection frames The compression mode parameter setting represented by the number counter value is then configured to the user equipment.

The compressed mode parameter setting represented by the RNC frame number counter (RFN) is converted into the compressed mode parameter setting represented by the connection frame number counter value (CFN) and includes:

5.1 Convert "compression mode parameter setting represented by RNC frame number counter (RFN)" to "compression mode parameter setting represented by NodeB frame number counter value (BFN)";

5.2 Convert "compression mode parameter setting represented by NodeB frame number counter value (BFN)" to "compression mode parameter setting represented by system frame number counter value (SFN)";

5.3 Convert "compression mode parameter setting represented by system frame number counter value (SFN)" to "compression mode parameter setting represented by connection frame number counter value (CFN)".

In the present invention, RNC obtains the occurrence time of SCH in the accurate BCCH51 multiframe by collecting UE's measurement results of BCCH51 multiframe time information of GSM adjacent cells, thereby can distribute appropriate compressed mode parameters to UE, and UE can use these compressed mode parameters The SCH can be accurately decoded in the defined compressed mode frame. In this way, we can ensure that the measurement performance required by the system is achieved, and at the same time, the number of compressed mode frames required is greatly reduced, the transmission power of the system is reduced, and the system capacity is improved.

Description of drawings

FIG. 1 is a schematic diagram of a compressed mode frame structure;

Fig. 2 is the distribution schematic diagram of GSM51 multiframe structure and SCH channel;

Figure 3 is a schematic diagram of a WCDMA UTRAN cell with a GSM neighboring cell;

Fig. 4 is a schematic diagram of timing information related to BCCH51 multi-frame time difference measurement and compressed mode parameters;

Fig. 5 is a flowchart of an embodiment of the present invention;

Detailed ways

The synchronization and timing mechanism in the WCDMA UTRAN (Universal Terrestrial RadioAccess Network, Universal Terrestrial Radio Access Network) utilized by the present invention are first described below (referring to 3GPP protocol 25.402):

BFN (NodeB Frame Number counter): Node-B frame number counter. Add 1 operation of modulo 4096 every 10ms, range 0～4095.

RFN (RNC Frame Number counter): RNC frame number counter. Add 1 operation of modulo 4096 every 10ms, range 0～4095.

SFN (Cell System Frame Number counter): cell system frame number counter. The SFN is sent on the cell broadcast channel, and the operation of adding 1 modulo 4096 is performed every 10 ms, and the range is 0 to 4095. The following relationship exists between SFN and BFN:

SFN＝(BFN-T_Cell)mod 4096 (1)

T_Cell is a delay value set by the Node-B to prevent overlapping of SCHs of subordinate cells.

CFN (Connection Frame Number counter): Connection frame number counter. Used for transmission channel synchronization between UTRAN and UE. Add 1 to modulo 256 every 10ms, the range is 0-255.

Frame_Offset and Chip_Offset: frame offset and chip offset, UTRAN sets these two parameters to determine the offset between CFN and SFN, as shown in the following formula:

SFN mod 256＝(CFN+Frame_Offset+Chip_Offset)mod 256 (2)

CFN＝(SFN-Frame_Offset-Chip_Offset)mod 256 (3)

RFN-BFN Offset: RNC and its subordinate Node-B can obtain the offset between RFN and BFN through the RNC-NodeB node synchronization process, namely:

RFN＝(BFN+RFN_BFN_Offset)mod 4096 (4)

The present invention can be divided into two parts: parameter acquisition and parameter configuration. The first part is used to obtain the timing information of the GSM cell from the measurement report of the UE; the second part is used to configure the parameters of the UE that needs compressed mode parameter configuration.

The present invention will be described in detail below according to the flowchart of an embodiment of the present invention shown in Fig. 5:

The first part of the present invention, i.e. the parameter acquisition process comprises:

1. The RNC orders the UE in the UTRAN cell to measure the BCCH51 multiframe timing information of the GSM neighboring cell.

2. The UE reports the measurement result to the RNC in the form of the difference between the start time of the BCCH51 multiframe of the GSM neighboring cell and the start time of the frame with SFN=0 in the cell where the UE resides. The measurement command and measurement report in step 1 and step 2 can be completed by using the signaling process in 3GPP protocol 25.331.

3. Since the cells where different UEs reside are not necessarily the same, even if the same GSM cell is measured, the measurement results of different UEs may be different. Therefore, an important part of the present invention is to convert these measurement results into the difference between the BCCH51 multiframe starting time of GSM adjacent cells and a common timing reference, so that the measurement results of different UEs on the same GSM cell can be unified. The public timing reference adopted in the present invention is the aforementioned RNC frame number counter RFN, because one RNC has only one unique RFN.

4. In order to complete the above conversion, the present invention first converts the measurement result from "the difference between the starting moment of the BCCH51 multiframe of the GSM adjacent cell and the starting moment of the frame with SFN=0 in the cell where the UE resides" into "GSM adjacent cell The difference between the starting time of the BCCH51 multiframe of the cell and the starting time of the frame with BFN=0 in the NodeB where the UE resides in the cell", as mentioned above, there is a known conversion formula (1) between SFN and BFN, So this conversion can be done by the formula;

5. Next to the previous step, the present invention converts the measurement result from "the difference between the starting time of the BCCH51 multiframe of the GSM adjacent cell and the starting moment of the frame of BFN=0 in the NodeB where the UE resides in the cell" to " The difference between the start time of the BCCH51 multiframe of the GSM adjacent cell and the start time of the frame where the UE resides in the RNC with RFN=0", as mentioned above, there is a conversion formula (4) between BFN and RFN, so this conversion It can be done with this formula.

6. Up to the last step, the RNC can obtain "the difference between the BCCH51 multiframe start time of the GSM adjacent cell and the start time of the frame of RFN=0 of the UE residing in the RNC" by the present invention. For the regularity and periodicity of the channel, the difference between the start time of each SCH frame of the corresponding GSM cell and the start time of the frame with RFN=0 of the RNC in this RFN cycle and any subsequent RFN cycle can be calculated according to the above difference . Such calculations can be easily performed by anyone who understands the present invention and the principles of GSM. In addition, the RNC may receive the measurement results of multiple UEs on the BCCH51 multiframe start time of the same GSM cell. After the above conversion is completed, these measurement results will have the same timing reference, so they can be reduced by averaging and other methods. UE's measurement error.

The procedure of the present invention includes the second part, that is, the parameter configuration part. According to the description of the parameter acquisition part of the present invention, the difference between the initial moment of the SCH frame of the target GSM cell in this RFN period and the frame initial moment of RFN=0 can be calculated, according to this difference we can determine that The RFN of the frames used for GSM measurements, configuring these frames as compressed mode frames, allows the UE to accurately decode and synchronize the SCH. However, the UE cannot directly set the compressed mode parameters represented by the RFN, because the UE does not know the RFN and therefore only accepts the parameter settings represented by the CFN. It is also necessary to convert the compression mode parameter setting represented by RFN to the compression mode parameter setting represented by CFN, and the conversion process is as follows:

1. Convert "compression mode parameter setting represented by RFN" to "compression mode parameter setting represented by CFN";

2. According to the formula (4), the "compression mode parameter setting represented by RFN" is converted into "compression mode parameter setting represented by BFN";

3. According to the formula (1), the "compression mode parameter setting represented by BFN" is converted into "compression mode parameter setting represented by SFN";

4. Convert the "compression mode parameter setting represented by SFN" into "compression mode parameter setting represented by CFN" according to formula (3);

5. Finally, configure the obtained "compression mode parameter setting represented by CFN" to the UE.

Let's illustrate with a more concrete example:

Consider the WCDMA UTRAN system shown in Figure 3, which consists of one RNC and two NodeBs, where every NodeB governs a cell. Both cells have a common GSM neighbor cell. The timing relationship between the various system nodes is shown in Figure 4, which will be described below in conjunction with these two figures.

In the initial state, the RNC does not know the timing information of the BCCH carrier frequency 51 multiframe of the GSM cell, so the RNC commands UE1 in cell 1 to measure the timing information of the BCCH 51 multiframe of the GSM adjacent cell (in the measurement control message, set "Observed time difference to GSM cell Reporting indicator" is set to True, and the format of the measurement control message can refer to 3GPP specification 25.331).

The UE measures the "Observed time difference to GSM cell", that is, the time difference T ₁ between the start of the multiframe of BCCH carrier frequency 51 in the GSM cell and the start of the frame with SFN=0 in the UTRAN cell, and reports the measurement result to the RNC.

According to the aforementioned UTRAN timing relationship, the RNC replaces _T1 with the difference _T2 between the BCCH51 multiframe start time of the GSM adjacent cell and the frame start time of RFN=0:

T ₂ =(T ₁ +T_Cell ₁ +RFN_BFN_Offset ₁ ) mod 4096

If UE2 in cell 2 needs to allocate compressed mode parameters for "BSICRe-confirmation" measurement at this time, the RNC calculates that RFN = T ₃ time is the time when the SCH channel of the GSM cell appears from the recorded T ₂ parameters, and then allocates it to the UE The compressed mode parameters ensure that the UE is exactly in the gap in the compressed mode frame at this moment. Since the start time of the compressed mode frame allocated to the UE in the specification is represented by CFN, the RNC will convert T ₃ into T ₄ :

T ₄ =[(T ₃ -T_Cell ₂ -RFN_BFN_Offset ₂ ) mod 4096

-ROUNDED(Frame_Offset+Chip_Offset)]mod 256

ROUNDED in the formula means rounding to the boundary of 256 chips.

The RNC then allocates appropriate compressed mode frame parameters to the UE, so that the UE can correctly decode the SCH at time _T4 in the space of the compressed mode frame.

Since the measurement and timing mechanism we adopt is provided by any WCDMA system conforming to the 3GPP standard, the present invention should be applicable to any standard WCDMA system.

Claims (3)

1, a kind of compact model measurement parameter collocation method comprises parameter acquiring process and parameter configuration process; Described parameter acquiring process specifically comprises:

2.1 radio network controller order subscriber equipment is measured the multi-frame timing information that comprises the GSM broadcast channel of neighboring GSM cell;

2.2 being the form of 0 the difference of frame between the zero hour with System Frame Number in the multi-frame zero-time that comprises the GSM broadcast channel of neighboring GSM cell and the user equipment to reside in cell with measurement result, subscriber equipment reports to radio network controller;

2.3 radio network controller is converted to the difference of the multi-frame zero-time that comprises the GSM broadcast channel of neighboring GSM cell to radio network controller frame number counter RFN with the measurement result of subscriber equipment report;

2.4 calculate difference between the zero hour that in the radio network controller frame number counter cycle radio network controller frame number counter value of each synchronizing channel frame zero hour of corresponding GSM sub-district and radio network controller is 0 frame according to above-mentioned difference, and according to the definite radio network controller frame number counter value that can be used for the frame of GSM measurement of this difference

Described parameter configuration process, comprise: calculate the radio network controller frame number counter value that can be used for the frame that GSM measures according to " the multi-frame zero-time that comprises the GSM broadcast channel of neighboring GSM cell and the frame number counter value of the resident radio network controller of subscriber equipment are the difference between zero hour of 0 frame ", and these frames are configured to compressed mode frame; To be converted to the compressed-mode parameter setting of representing with the Connection Frame Number Counter Value with the compressed-mode parameter setting of radio network controller frame number counter value representation again, subscriber equipment is given in configuration then.

2, the described compact model measurement parameter of claim 1 collocation method, it is characterized in that the transfer process described in the step 2.3 comprises: earlier measurement result is converted to from " System Frame Number is the difference between zero hour of 0 frame the initial moment of the multi-frame that comprises the GSM broadcast channel of neighboring GSM cell and the user equipment to reside in cell " " under the initial moment of the multi-frame that comprises the GSM broadcast channel of neighboring GSM cell and the user equipment to reside in cell among the Node B NodeB frame number counter value be difference between zero hour of 0 frame "; Be converted to " the multi-frame zero-time that comprises the GSM broadcast channel of neighboring GSM cell and the frame number counter value of the resident radio network controller of subscriber equipment are the difference between zero hour of 0 frame " again.

3, the described compact model measurement parameter of claim 1 collocation method, it is characterized in that, describedly will be converted to the compressed-mode parameter setting of representing with the Connection Frame Number Counter Value with the compressed-mode parameter setting of radio network controller frame number counter value representation and comprise:

5.1 " with the compressed-mode parameter setting of radio network controller frame number counter value representation " is converted to " with the compressed-mode parameter setting of NodeB frame number counter value representation ";

5.2 " with the compressed-mode parameter setting of NodeB frame number counter value representation " is converted to " with the compressed-mode parameter setting of System Frame Number value representation ";

5.3 " with the compressed-mode parameter setting of System Frame Number value representation " is converted to " the compressed-mode parameter setting of representing with the Connection Frame Number Counter Value ".

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