KR20100041602A - Method of transmitting measurement report message in wireless communication system - Google Patents

Abstract

PURPOSE: A method of transmitting a measurement report message in a wireless communication system is provided to reduce the information amount of a report value included in a measurement report message. CONSTITUTION: A measurement values of a signal characteristic value of an adjacent cell is mapped to a report value classified based on the serving cell signal strength of a signal characteristic value of a serving cell. A measurement report message including the reporting value is transmitted. The measurement value is an RSRP(Reference Signal Received Power), and the serving cell is a GSM(Global System for Mobile communication)/GPRS(General Packet Radio Service) cell. The adjacent cell is an E-UTRAN(Evolved-UMTS Terrestrial Radio Access Network) cell.

Description

METHOD OF TRANSMITTING MEASUREMENT REPORT MESSAGE IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to wireless communication, and more particularly, to a method for transmitting a measurement report message in a wireless communication system.

The next generation multimedia wireless communication system, which is being actively researched recently, requires a system capable of processing and transmitting various information such as video, wireless data, etc., out of an initial voice-oriented service. The purpose of a wireless communication system is to enable a large number of users to communicate reliably regardless of location and mobility.

The wireless communication system provides a communication service by dividing the service area into a plurality of cells in order to overcome the limitation of the service area and the user capacity. This is called a multi-cell environment. A cell providing a service to a terminal is called a serving cell, and another cell adjacent to the serving cell is called a neighbor cell. The wireless communication system is different from the wired communication system in that it is necessary to provide endless services to mobile terminals. When the terminal moves its position from the serving cell to the neighbor cell, it is necessary to change the moved neighbor cell to the serving cell to provide a continuous service to the terminal. As such, a procedure of changing the serving cell of the terminal due to the movement of the terminal is referred to as handover.

However, the neighbor cell may be a radio access technology (RAT) cell different from the serving cell. RAT is a type of technology used for radio access. For example, RAT includes Global System for Mobile communication (GSM) / General Packet Radio Service (GPRS), Universal Mobile Telecommunications System (UTTS) Terrestrial Radio Access Network (UTTS), and Evoloved-UMTS Terrestrial Radio Access Network (E-UTRAN). Etc. There are also various RATs.

GSM is a wireless technology developed as a system for standardizing wireless communication systems in Europe, and GPRS is intended to provide a packet switched data service in a circuit switched data service provided by GSM. Technology. GSM / GPRS is a system based on TDMA. GSM / GPRS may be referred to as a second generation wireless communication system. UMTS may be referred to as a third generation wireless communication system based on wideband code division multiple access (WCDMA). E-UTRAN is a wireless communication system based on Orthogonal Frequency Division Multiple Access (OFDMA). E-UTRAN is also called Long Term Evolution (LTE). The GSM cell is a cell of which RAT is GSM / GPRS, the UTRAN cell is a cell of which RAT is UMTS, and the E-UTRAN cell is a cell of which RAT is E-UTRAN.

As various types of RATs emerge, interoperability between existing RATs such as GSM / GPRS and UMTS is problematic. Even if a new RAT is introduced, compatibility with existing GSM / GPRS is convenient for the user, and the operator can also reuse the existing equipment. For interoperation between different RATs, the UE may support multi-RAT. The terminal supporting the multi-RAT may support not only GSM but also UMTS, E-UTRAN, and the like. For example, if the serving cell is a GSM cell, the terminal supporting the multi-RAT may handover to an adjacent E-UTRAN cell.

The UE supporting the multi-RAT belonging to the GSM cell may measure not only the GSM neighbor cell but also the UMTS cell or the E-UTRAN cell, and report the measurement result to the base station. The mobile terminal can be provided with a service from a suitable cell through the transmission of the measurement report message. Through this, the terminal may maintain a quality of service and receive a better signal. Therefore, the transmission of the measurement report message to the neighbor cell of the terminal is very important.

Therefore, there is a need to provide an efficient measurement report message transmission method.

The technical problem to be achieved by the present invention is to provide an efficient measurement report message transmission method.

In one aspect, a method of transmitting a measurement report message in a wireless communication system is provided. The method may include mapping a measurement value, which is a signal characteristic value of an adjacent cell, to a report value divided based on a serving cell signal strength, which is a signal characteristic value of a serving cell, and transmitting a measurement report message including the report value. Include.

In another aspect, a processor for mapping a measurement value, which is a signal characteristic value of an adjacent cell, to a report value divided based on a serving cell signal strength, which is a signal characteristic value of a serving cell, and an RF for transmitting a measurement report message including the report value. It provides a terminal including a (Radio Frequency) unit.

It is possible to provide an efficient method for transmitting a measurement report message. The amount of information of the report value included in the measurement report message can be reduced. Through this, limited radio resources can be used efficiently. Thus, overall system performance can be improved.

1 is a block diagram illustrating a wireless communication system. This represents a GSM (Global System for Mobile communication) / GPRS (General Packet Radio Service) based network. Hereinafter, GPRS may include not only general GPRS but also Enhanced GPRS (EGPRS) / EGPRS2. Wireless communication systems are widely deployed to provide various communication services such as voice, packet data, and the like.

Referring to FIG. 1, a mobile station (MS) 10 refers to communication equipment carried by a user, and includes a user equipment (UE), a user terminal (UT), a subscriber station (SS), and a wireless device (wireless device). Etc. may be called.

A base station (BS) 20 includes a base transceiver station (BTS) 22 and a base station controller (BSC) 24. The BTS 22 communicates with the terminal 10 in one cell area through a radio interface and performs a function such as synchronization with the terminal 10. The BSC 24 interfaces at least one BTS 22 with the Mobile Switching Center (MSC) 30.

The MSC 30 connects a heterogeneous network such as a Public Switching Telephone Network (PSTN) 65 or a Public Land Mobile Network (PLMN) to the base station 20 through a Gateway MSC (GMSC) 60. The VLR (Visitor Location Register) 40 stores temporary user data and includes information about roaming of all terminals 10 in the MSC 30 service area. The Home Location Register (HLR) 50 contains information about all subscribers in the home network. The Serving GPRS Support Node (SGSN) 70 is responsible for mobility management of subscribers. The Gateway GPRS Support Node (GGSN) routes the packet to the current location of the terminal 10 and interfaces with an external packet data network such as a public data network (PDN) 85.

2 is a block diagram illustrating elements of a terminal. The terminal 50 includes a processor 51, a memory 52, an RF unit 53, a display unit 54, and a user interface unit 55. ). The processor 51 is implemented with layers of the air interface protocol to provide a control plane and a user plane. The functions of each layer may be implemented through the processor 51. The memory 52 is connected to the processor 51 to store a terminal driving system, an application, and a general file. The display unit 54 displays various information of the terminal, and may use well-known elements such as liquid crystal display (LCD) and organic light emitting diodes (OLED). The user interface unit 55 may be a combination of a well-known user interface such as a keypad or a touch screen. The RF unit 53 is connected to a processor and transmits and / or receives a radio signal.

Hereinafter, it is assumed that the serving cell is a GSM cell, and neighbor cells are GSM cells, UTRAN cells, or E-UTRAN cells. In addition, it is assumed that the terminal supports multi-RAT.

The terminal measures the GSM cell or the UTRAN cell according to the indication of the base station and transmits the measurement result to the base station. When the base station determines that the serving cell needs to be changed to the E-UTRAN cell for the terminal, the base station informs the terminal of the E-UTRAN center frequency and instructs E-UTRAN cell measurement. The terminal measures the signal characteristic value for the E-UTRAN cell.

The signal characteristic value is received signal strength information from a serving cell or neighbor cells measured by the terminal. For example, the signal characteristic values include RSSI (Reseived Signal Strength Indicator), RSCP (Received Signal Code Power), RSRP (Reference Signal Received Power), path loss criterion parameter, and the like. The received signal strength information used as the signal characteristic value may be different for each RAT type. For example, in the case of a GSM cell, the terminal may measure the path loss reference parameter as a signal characteristic value. In the case of a UTRAN cell, the terminal may measure RSCP as a signal characteristic value. In the case of an E-UTRAN cell, the terminal may measure the RSRP as a signal characteristic value.

The terminal measures the RSRP for the E-UTRAN cell. The terminal reports the RSRP measurement result to the base station. This is called a measurement report. The measurement report may be performed by transmitting a MEASUREMENT REPORT message including a received signal level (RXLEV) field. The received signal level is information on the RSRP measurement result. The terminal performing the measurement report may be in a packet idle mode, a packet transfer mode, a dedicated mode, or a dual transfer mode (DTM).

In order to deliver measurement results for the E-UTRAN cell to the base station, first, a new measurement report message format may be defined and used. Second, existing measurement report messages can be used.

First, the case of defining a new measurement report message format is described. The UE may report the measurement to the base station using the newly defined measurement report message format. The new measurement report message type can be defined to suit the E-UTRAN cell. Therefore, the terminal can perform the measurement report relatively simply. However, the addition of new measurement report message formats can increase complexity in terms of standards and implementations. This is because the addition of a new uplink message may reduce the efficiency of radio resource management of the base station and increase the signaling load. In addition, problems may arise in backward compatibility with existing systems.

Second, the case of using the existing measurement report message will be described. Existing measurement report messages include MEASUREMENT REPORT messages, PACKET MEASUREMENT REPORT messages, extended ENHANCED MEASUREMENT REPORT messages, or enhanced packet measurement report messages.

3 shows an example of an existing GSM neighbor cell measurement report message.

Referring to FIG. 3, the GSM neighbor cell measurement report message may be 17 bits. The GSM neighbor cell measurement report message includes a 6-bit neighbor cell received signal level (RXLEV NCell) field, a 5-bit neighbor cell Broadcast Control Channel (BCCH) frequency (BCCH Freq NCell) field, and a 6-bit neighbor cell Base transceiver Station (BSIC). It may include an Identity Code (BSIC NCell) field.

In order to indicate the measurement result of the E-UTRAN cell using the MEASUREMENT REPORT message, the measurement result of the E-UTRAN neighbor cell should be adjusted to the size of one GSM neighbor cell measurement result field. E-UTRAN center frequency, physical cell identity (PCID), RSRP, etc. must be changed to match the existing GSM neighbor cell reporting field.

However, in order to perform handover correctly, the physical cell identifier of the E-UTRAN cell must be known correctly. E-UTRAN cells are distinguished by 504 physical cell identifiers. 9 bits are required to represent the physical cell identifier of the E-UTRAN cell. In order not to reduce the physical cell identifier field (9 bits) in the MEASUREMENT REPORT message, the received signal level field may be reduced in the existing GSM neighbor cell measurement report message.

4 illustrates an example of applying a measurement report message of an existing GSM neighbor cell to a measurement report message of an E-UTRAN neighbor cell.

4 shows an example of applying an existing GSM neighbor cell measurement report message to the measurement report of the E-UTRAN neighbor cell.

Referring to FIG. 4, the E-UTRAN neighbor cell measurement report message is 17 bits. The E-UTRAN Neighbor Cell Measurement Report message consists of a 3-bit E-UTRAN Neighbor Cell Measurement Report (EUTRAN Ncell MR) field, a 5-bit "30-n" field, a 6-bit PCID High field, and a 3-bit It may include a PCID low field. The PCID high field and the PCID low field may be used to represent a physical cell identifier of a 9-bit E-UTRAN cell. The "30-n" field uses the neighbor cell BCCH frequency field of the GSM neighbor cell measurement report message. In order to use the 9-bit physical cell identifier of the E-UTRAN cell as it is, the E-UTRAN neighbor cell measurement report field is reduced to 3 bits.

The following table shows an example of measurement report mapping of RSRP.

비트가 필요하다(N은 자연수). Referring to the table, the reporting range of RSRP has a resolution of 1 dB from -140 dBm to -44 dBm. This mapping method is called full reporting resolution. There are 98 RSRP Reported Values from RSRP_00 to RSRP_97. At least 7 bits are required to represent 98 code points as an RSRP report value. If there are N values in the reported value, the length of the reported value is

A bit is needed (N is a natural number).

However, the RXLEV field of the existing measurement report message is composed of 6 bits. Therefore, applying full report resolution to existing measurement report messages is problematic.

To solve this problem, we first consider how to use 2 dB resolution for the entire RSRP range. Two RSRP Measured quantity values may be mapped to one RSRP report value. 49 code points may represent a full range of RSRP. RSRP encoding using 6 bits is possible. Among the existing measurement report messages, the packet measurement report message, the extended measurement report message, or the enhanced packet measurement report message can be extended to allow 2 dB resolution. .

However, in the case of the measurement report message, the total message length is fixed, including the measurement result field for six adjacent cells. Therefore, the 2 dB resolution method cannot be used to deliver the measurement report message for six E-UTRAN cells using the MEASUREMENT REPORT message.

In order not to reduce the physical cell identifier field in the MEASUREMENT REPORT message, it is necessary to consider how to express RSRP schematically. For example, when the E-UTRAN neighbor cell measurement report field is called an RSRP field, the length of the RSRP field may be 3 bits. If the length of the RSRP field is 3 bits, 8 code points should be used to express the RSRP report value. Hereinafter, a method of schematically expressing RSRP will be described. It is assumed that the length of the RSRP field is 3 bits, but the length of the RSRP field is changeable.

(1) First example

5 shows a first example of an RSRP encoding method.

Referring to FIG. 5, RSRP measurements are classified based on Serving Cell Signal Strength (SCSS) and mapped to RSRP reports. Specifically, all RSRP measurements smaller than the serving cell signal strength are mapped to one RSRP report value (RSRP_0), and the RSRP measurements larger than the serving cell signal strength are subdivided by signal strength and mapped to the RSRP report values (RSRP_1 to RSRP_7). Let's do it. When handing over from an GSM cell as a serving cell to an E-UTRAN cell as an adjacent cell, it is assumed that there is a high possibility of handover to an E-UTRAN cell having better signal strength than the GSM cell.

The following table shows a first example of measurement report mapping of RSRP.

Referring to the table, all RSRP measurements smaller than the serving cell signal strength are mapped to one RSRP report value, RSRP_0. Measurements from the serving cell signal strength to measurements as large as a (dB) are mapped to report value RSRP_1, and then measurements to RSRP_2 to measurements as large as b (dB). In this way, the RSRP measurement is mapped up to the report value RSRP_6. RSRP measurements greater than the range of RSRP measurements mapped to report value RSRP_6 are mapped to RSRP_7. In this way, the entire range of RSRP measurements can be mapped to RSRP reports. Reported values RSRP_0 to RSRP_7 can have multiple resolutions from a to f or more. In this case, all of a to f may be the same value or may be different values.

6 shows a second example of an RSRP encoding method.

Referring to FIG. 6, the RSRP measurement value is classified based on the serving cell signal strength (SCSS) and mapped to the RSRP report value. Specifically, the RSRP measurement value smaller than the serving cell signal strength is not mapped to the RSRP report value, and only the RSRP measurement values larger than the serving cell signal strength are subdivided by signal strength and mapped to the RSRP report values RSRP_0 to RSRP_7. Since it is assumed that there is a high possibility of handover to an E-UTRAN cell having a better signal strength than the GSM cell, the UE does not need to report measurement on the E-UTRAN cell having an RSRP measurement smaller than the serving cell signal strength.

The following table shows a second example of measurement report mapping of RSRP.

Referring to the table, RSRP measurements smaller than the serving cell signal strength are not mapped to the reported values. Except for this, it is similar to Table 2. Reported values RSRP_0 to RSRP_7 can have multiple resolutions from a to g or more. In this case, all of a to g may be the same value or different values.

7 shows a third example of an RSRP encoding method.

Referring to FIG. 7, RSRP measurement values are classified based on serving cell signal strength (SCSS) and mapped to RSRP report values. Specifically, RSRP report values are mapped by dividing the range of RSRP measurement values based on the serving cell signal strength. When handing over from an GSM cell, which is a serving cell, to an E-UTRAN cell, which is an adjacent cell, it is assumed that there is a high possibility of handover to an E-UTRAN cell regardless of the serving cell signal strength.

The following table shows a third example of measurement report mapping of RSRP.

Referring to the table, from the serving cell signal strength to a measurement as large as a (dB) is mapped to the report value RSRP_4, the next measurement to a measurement as large as b (dB) is mapped to RSRP_5 and then to the next measurement To a measurement as large as c (dB) is mapped to RSRP_6. RSRP measurements greater than the range of measurements mapped to RSRP_6 are mapped to RSRP_7. From the serving cell signal strength to measurements as small as d (dB), are mapped to the report value RSRP_3, and the measurement from d (dB) less than the serving cell signal strength to the measurement as small as (d + e) (dB). Is mapped to RSRP_2. Measurements smaller by (d + e) (dB) than serving cell signal strength to measurements smaller by (d + e + f) (dB) are mapped to report value RSRP_1. From the measured value smaller by (d + e + f) (dB) than the serving cell signal strength, it is mapped to the report value RSRP_0. In this way, the entire range of RSRP measurements can be mapped to RSRP reports. Reported values RSRP_0 to RSRP_7 can have multiple resolutions from a to f or more. In this case, all of a to f may be the same value or may be different values.

8 shows a fourth example of an RSRP encoding method.

Referring to FIG. 8, the RSRP measurement value is classified based on the serving cell signal strength (SCSS) and mapped to the RSRP report value. Specifically, RSRP report values are mapped by dividing the range of RSRP measurement values based on the serving cell signal strength. In this case, it is assumed that most of the RSRP measurements based on the serving cell signal strength may be included in the RSRP_0 or RSRP_7 region. Therefore, a measurement value having a specific value or more than the serving cell or a measurement value having a specific value or less than the serving cell is not reported.

The following table shows a fourth example of measurement report mapping of RSRP.

Referring to the table, measurements greater than (a + b + c + d) (dB) from the serving cell signal strength and measurements less than (e + f + g + h) (dB) from the serving cell signal strength are It is not mapped to the reported value. Except for this, it is similar to Table 4. Reported values RSRP_0 to RSRP_7 may have several resolutions from a to h or more. In this case, all of a to h may be the same value or may be different values.

9 shows a fifth example of an RSRP encoding method.

Referring to Figure 9, a separate RSRP measurement value as an upper limit based on the threshold (Threshold _high) and a lower limit threshold (Threshold _low). Specifically, when the RSRP measurement value is larger than the upper limit threshold line, and when the RSRP measurement value is smaller than the lower limit threshold line, the case where the RSRP measurement value is between the upper limit line and the lower limit line is distinguished and mapped to the RSRP report value. The terminal may receive the information on the upper limit line and the information on the lower limit line from the base station. In this case, the terminal may receive information about an upper limit line and information about a lower limit line through a broadcast channel or a dedicated channel.

The following table shows a fifth example of measurement report mapping of RSRP.

Referring to the table, when the RSRP measurement value is smaller than the lower limit threshold, the RSRP report value is mapped to RSRP_0. If the RSRP measurement is greater than the upper threshold, then the RSRP report is mapped to RSRP_7. The RSRP range between the upper threshold line and the lower threshold line is divided into six regions and mapped to report values RSRP_1 to RSRP_6, respectively. The upper threshold line is the same as "lower threshold line + (a + b + c + d + e + f)". Reported values RSRP_0 to RSRP_7 can have multiple resolutions from a to f or more. In this case, all of a to f may be the same value or may be different values.

10 shows a sixth example of an RSRP encoding method.

10, divides the value of the upper limit based on the measured RSRP threshold (Threshold _high) and a lower limit threshold (Threshold _low). Specifically, when the RSRP measurement value is larger than the upper limit threshold, the measurement report is not reported when the RSRP measurement value is smaller than the lower limit threshold.

The following table shows a sixth example of measurement report mapping of RSRP.

Referring to the table, RSRP measurements larger than the upper threshold or RSRP measurements smaller than the lower threshold are not mapped to the reported values. Except for this, it is similar to Table 6. The upper threshold line is the same as the "lower threshold line + (a + b + c + d + e + f + g + h)". Reported values RSRP_0 to RSRP_7 may have several resolutions from a to h or more. In this case, all of a to h may be the same value or may be different values.

By using any one of the first to sixth examples of the measurement report mapping of the RSRP described above, the terminal may map the measurement value of the neighbor cell to one report value. The terminal transmits a measurement report message including the report value.

In addition, in any one of the first to sixth examples of measurement report mapping of RSRP described above, one or more RSRP measurement values may be mapped to one RSRP report value. It is necessary to distinguish between E-UTRAN cells having the same RSRP report value. To this end, the UE may include in the measurement report message from the E-UTRAN cell having a large RSRP measurement value.

As such, when the RSRP report value is represented by 8 code points, RSRP of the E-UTRAN cell can be encoded with 3 bits. Therefore, all existing measurement report messages, such as MEASUREMENT REPORT messages, PACKET MEASUREMENT REPORT messages, ENHANCED MEASUREMENT REPORT messages, or Enhanced Packet Measurement Report (PACKET ENHANCED MEASUREMENT REPORT) messages. The measurement report for the E-UTRAN cell is enabled using a message or the like. In addition, when defining a new measurement report message format, the amount of information in the RSRP report value can be reduced. Through this, limited radio resources can be used efficiently. Thus, overall system performance can be improved.

The invention can be implemented in hardware, software or a combination thereof. (DSP), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microprocessor, and the like, which are designed to perform the above- , Other electronic units, or a combination thereof. In the software implementation, the module may be implemented as a module that performs the above-described function. The software may be stored in a memory unit and executed by a processor. The memory unit or processor may employ various means well known to those skilled in the art.

Although the present invention has been described above with reference to the embodiments, it will be apparent to those skilled in the art that the present invention may be modified and changed in various ways without departing from the spirit and scope of the present invention. I can understand. Therefore, the present invention is not limited to the above-described embodiment, and the present invention will include all embodiments within the scope of the following claims.

1 is a block diagram illustrating a wireless communication system.

2 is a block diagram illustrating elements of a terminal.

3 shows an example of an existing GSM neighbor cell measurement report message.

4 illustrates an example of applying a measurement report message of an existing GSM neighbor cell to a measurement report message of an E-UTRAN neighbor cell.

5 shows a first example of an RSRP encoding method.

6 shows a second example of an RSRP encoding method.

7 shows a third example of an RSRP encoding method.

8 shows a fourth example of an RSRP encoding method.

9 shows a fifth example of an RSRP encoding method.

10 shows a sixth example of an RSRP encoding method.

Claims (11)

In a method of transmitting a measurement report message in a wireless communication system, Mapping a measurement value, which is a signal characteristic value of an adjacent cell, to a report value divided based on a serving cell signal strength, which is a signal characteristic value of a serving cell; And And transmitting a measurement report message including the report value. The method of claim 1, The measurement value is a measurement report message transmission method, characterized in that the RSRP (Reference Signal Received Power). The method of claim 1, The serving cell is a method for transmitting a measurement report message, characterized in that the GSM (Global System for Mobile communication) / GPRS (General Packet Radio Service) cell. The method of claim 1, The adjacent cell is a measurement report message transmission method, characterized in that the E-UTRAN (Evloved-UMTS Terrestrial Radio Access Network) cell. The method of claim 1, And the measurement report message further comprises a cell identifier of the neighbor cell. The method of claim 1, The measurement report message further includes a second report value to which a second measurement value of a second neighboring cell is mapped. If the report value and the second report value are the same, the measurement report message further includes one of the measured value and the second measurement value. Method for transmitting a measurement report message, characterized in that it comprises a report value corresponding to the large measurement value first. The method of claim 1, The report value corresponds to a region to which the measurement value belongs among N (N is a natural number) regions, wherein the N region is a measurement report range of the adjacent cell is divided based on the serving cell signal strength. How to send a measurement report message. The method of claim 7, wherein And a portion of the N regions is larger than the serving cell signal strength, and the remaining regions are smaller than the serving cell signal strength. The method of claim 7, wherein The measurement report reporting range of the neighbor cell is a measurement report message transmission method, characterized in that the measured value is larger than the lower threshold, the measured value is smaller than the upper threshold. The method of claim 7, wherein The reported value is

Method of transmitting a measurement report message, characterized in that the binary number. A processor configured to map the measured value, which is a signal characteristic value of an adjacent cell, to a report value divided based on the serving cell signal strength, which is a signal characteristic value of a serving cell; And And a radio frequency (RF) unit for transmitting a measurement report message including the report value.

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