KR102042173B1 - Method and apparatus for monitoring radio link based on frequency region in wireless communication system - Google Patents

Abstract

The present invention relates to a radio link monitoring technology, a method for operating a base station and a terminal, and a method for evaluating a radio link quality in a wireless communication system. The terminal includes a process of performing radio link quality evaluation and a radio link quality evaluation method. In addition, the UE includes the process of transmitting the frequency domain quality information to the base station after the radio link quality evaluation to be utilized for the downlink resource allocation of the base station.
By using the above method, despite the existence of a frequency range in which a service can be provided in the downlink channel band, the terminal enters a physical layer abnormality and a radio link failure state or the terminal performs an unnecessary handover. I can solve it.

Description

METHOD AND APPARATUS FOR MONITORING RADIO LINK BASED ON FREQUENCY REGION IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to a wireless communication system. More specifically, the present invention relates to a radio link monitoring technique, a method of operating a base station and a terminal, and a method of evaluating radio link quality.

In a wireless communication system, a UE measures a downlink channel state currently connected from a base station, and evaluates downlink quality based on this to determine whether a corresponding link can provide a reliable level of service. ). As a representative example, in the Long Term Evolution (LTE) system, which is a next generation mobile communication system of the 3rd Generation Partnership Project (3GPP), the asynchronous cellular mobile communication standard group, Common Reference Signal (CRS), that is, a reference signal transmitted from the base station to the downlink, is common It is standardized to perform radio link monitoring by evaluating link quality by measuring channel state from a reference signal. Here, the reference signal that can be received by the UE through the downlink of the LTE system is a channel state information RS (CSI-RS), which is a channel state information reference signal, a demodulation reference signal (DM RS), etc. in addition to the common reference signal. Can be mentioned.

The terminal performs filtering on common reference signal-based measurement values during the previous specific time interval and compares the result with specific thresholds to evaluate the radio link quality. The specific thresholds are determined as signal levels satisfying a specific block error rate (BLER) of the physical downlink control channel PDCCH (Physical Downlink Control Channel) distributed and transmitted over the downlink channel band. The current standard defines the threshold Q_out as the level corresponding to the 10% block error rate and the threshold Q_in as the level corresponding to the 2% block error rate. The UE sets threshold Q_out and Q_in values, which are levels corresponding to respective hypothesis block error rates, during PDCCH transmission considering the physical control format indicator channel PCFICH (Physical Control Format Indicator Channel) error rate. Compare the resulting levels.

If the level of the radio link quality evaluation result of the terminal is lower than the specific threshold Q_out, the current radio link quality is determined as “Out-of-sync”. If the level is higher than the threshold Q_in, the current radio link quality is “In-sync”. Determine with. "Out-of-sync" means that the current downlink state is not reliable, and "In-sync" indicates that the current downlink state is reliable. After the determination, the terminal physical layer transmits an “out-of-sync indication” or an “in-sync indication” to the terminal higher layer according to the determination result.

When the "out-of-sync indication" appears more than a certain number of times, the upper layer of the UE detects that there is an abnormality in the current downlink quality and switches the state of the terminal to a physical layer problem detection state. At this time, the specific timer starts to operate. If the state of the terminal does not recover from the physical layer abnormality detection state until the timer expires, a radio link failure is determined. On the other hand, if the state of the terminal receives the "In-sync indication" a certain number of times in succession from the physical layer before the timer expires, it recovers from the physical layer abnormality detection state to a normal state.

3GPP release 11, which is currently being standardized, is discussing the introduction of a new type of additional carrier type in which a common reference signal is not transmitted. As a result, existing radio link monitoring methods based on common reference signals cannot be used.

In particular, new types of carriers are likely to be configured with frequency division multiplexing (FDM). Therefore, in the new type of carrier, if the reliable quality is maintained even in some frequency domains of the downlink channel band, an environment in which downlink service is available to the terminal will be created.

In this environment, when Q_out and Q_in are determined based on the hypothetical block error rate of the PDCCH that is distributed and transmitted throughout the channel band in the conventional manner, the degree of downlink maintenance in some frequency domains is possible when the average quality of the entire channel band is lower than Q_out. Even with the reliability of out-of-sync ”can be determined. Similarly, even though the downlink quality of some frequency domains is sufficient to judge “in-sync”, the average quality of the entire channel band is lower than Q_in, so that “in-sync” determination may not be possible.

For example, in the case of using the conventional radio link quality estimation method on a new type of carrier, as shown in FIG. 1, Q_out 100 is set and the average channel state measured by the UE for the entire downlink channel band is averaged. A situation with a value of 101 may occur. Here, although the UE still has a better channel state than Q_out, a reliable frequency region 102 capable of allocating a control channel and a data channel is present in the downlink channel band. -sync ”.

The above-mentioned phenomenon is particularly likely to occur in terminals located outside the cell where the average quality of the entire channel band is near the threshold. As a result, although the service may be provided from the currently connected cell, the UE may perform an unnecessary operation by performing an unnecessary handover to an adjacent cell or entering into a physical layer abnormality detection and a radio link failure state.

Therefore, there is a need for a new technology that can solve the above problems and support smooth wireless link monitoring.

The present invention is derived to solve the problems of the background art as described above, an object of the present invention is to provide a radio for at least one or more frequency domains divided in the downlink channel band when the terminal performs radio link monitoring in a wireless communication system A method and apparatus for performing link quality evaluation are provided.

Still another object of the present invention is to allow a terminal to transmit information on the frequency domain quality to a base station through uplink, and the base station allocates a control channel and a data channel for the corresponding terminal based on the frequency domain quality information received from the terminal. A method and apparatus are provided.

According to a first aspect of the present invention for achieving the above object, a step in which a terminal performs a channel state measurement and evaluation for each of at least one frequency region divided within a downlink channel band in a wireless communication system It features.

According to a second aspect of the present invention for achieving the above objects, in the wireless communication system, "out-of-sync" for the radio link quality based on the channel state measurement and evaluation for each of the aforementioned frequency domain and It is characterized by including the process of performing wireless link monitoring by determining the "In-sync".

According to a third aspect of the present invention for achieving the above objects, a terminal transmits an uplink resource allocation request such as a scheduling request or a random access to a base station in a wireless communication system and accordingly And transmitting the frequency domain quality information obtained as a result of the radio link quality evaluation to the base station through the uplink resource allocated from the base station.

According to a fourth aspect of the present invention for achieving the above objects, in a wireless communication system, a base station performs a process of allocating a downlink control channel and a data channel for a corresponding terminal based on frequency domain quality information received from the terminal. It is characterized by including.

According to a fifth aspect of the present invention for achieving the above objects, in a wireless communication system, when a terminal requests an uplink resource to transmit frequency domain quality information and then does not receive the requested resource allocation information from the base station, the corresponding terminal is downward. And performing a radio link quality assessment for the entire link channel band.

According to a sixth aspect of the present invention for achieving the above objects, in a wireless communication system, a terminal performs quality evaluation of the aforementioned frequency domains, and as a result, it is determined that the quality of all frequency domains is reliable or that the quality of all frequency domains is reliable. If it is determined that this is not reliable, characterized in that it comprises the step of not performing the transmission of the frequency domain quality information through the uplink channel.

More specifically, in the wireless communication system of the present invention, a method for monitoring a radio link of a terminal includes: a division step of dividing a downlink channel band into a plurality of frequency domains for performing radio link monitoring, and a channel state for each of the divided frequency domains And a determination step of determining a wireless link quality result as in-sync or out-of-sync based on the measurement result.

In addition, the terminal for monitoring the radio link in the wireless communication system of the present invention, a transceiver for transmitting and receiving a signal to and from the base station, the downlink channel band is divided into a plurality of frequency domains for performing radio link monitoring, the divided frequency domain A channel measuring unit for measuring a channel state for each, and a radio link quality evaluating unit for determining a radio link quality result as in-sync or out-of-sync based on the measurement result. It features.

In the present invention, the terminal performs radio link quality evaluation on at least one frequency domain divided within the downlink channel band and transmits frequency domain quality information to the base station. The base station receives the frequency domain quality information from the terminal and utilizes the control channel and data channel allocation for the terminal.

Therefore, even though there is a frequency range in which a service can be provided in a downlink channel band that may occur in the conventional radio link monitoring method, the terminal may enter into a physical layer abnormality and a radio link failure state. In addition, when there is a frequency domain in which a service can be provided in a downlink channel band, it is possible to make full use of it and to prevent unnecessary handover operation of the terminal.

1 is a diagram illustrating a problem when a terminal uses a conventional radio link monitoring method;
2 is a diagram illustrating a method of dividing a downlink channel band into at least one frequency region for monitoring a radio link in a wireless communication system according to an embodiment of the present invention;
3 is a diagram illustrating a procedure for a terminal to perform a radio link quality evaluation in a wireless communication system according to an embodiment of the present invention;
4 is a diagram illustrating another procedure for a terminal to perform a radio link quality evaluation in a wireless communication system according to an embodiment of the present invention;
FIG. 5 is a diagram illustrating a procedure of transmitting, by a terminal, frequency domain quality information to a base station in a wireless communication system according to an embodiment of the present invention;
6 is a diagram illustrating another procedure of transmitting, by a terminal, frequency domain quality information to a base station in a wireless communication system according to an embodiment of the present invention;
FIG. 7 is a diagram illustrating an example in which a terminal inserts frequency domain quality information into a PUSCH (Physical Uplink Shared Channel) in a wireless communication system according to an embodiment of the present invention; FIG.
FIG. 8 is a diagram illustrating another example of inserting frequency domain quality information into a physical uplink shared channel (PUSCH) by a terminal in a wireless communication system according to an embodiment of the present invention; FIG.
9 is a diagram illustrating a configuration of a base transceiver station in a wireless communication system according to an embodiment of the present invention;
10 is a diagram showing the configuration of a terminal transceiver in a wireless communication system according to an embodiment of the present invention;
11 is a diagram illustrating an operation procedure of a base station in a wireless communication system according to an embodiment of the present invention;
12 is a diagram illustrating a terminal operation procedure in a wireless communication system according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of related well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification.

Hereinafter, the present invention will be described with reference to the radio link monitoring (Radio link monitoring) performed by the terminal based on at least one or more frequency domain in the downlink channel band, the operation procedure of the base station and the terminal and the method of evaluating the radio link quality.

In the present invention, a base station uses a new type of carrier and transmits not only a downlink data channel but also a control channel using a frequency division multiplexing (FDM) method. In addition, a reference signal (RS), that is, a reference signal, which can be used for wireless link monitoring of a terminal, is a common reference signal (CRS) or a channel state information reference signal (CSI-RS). In the following description of an embodiment of the present invention, it is assumed that a common reference signal is not transmitted when using a new type of carrier. Accordingly, the terminal according to the embodiment of the present invention utilizes the measurement result from the channel state information reference signal for radio link monitoring. However, the present invention is not limited to using the channel state information reference signal of the embodiment, and other reference signals such as a common reference signal may be used.

In the present invention, the downlink channel band is divided into at least one or more frequency domains for wireless link monitoring. To this end, the base station informs the terminal of the setting of the divided frequency domain. Here, the configuration of the frequency domain of the base station may be transmitted to the terminal through RRC signaling and the like, and the corresponding configuration information may include the size, number, and position on the frequency domain. The terminal measures a channel state in each frequency domain and evaluates the quality of each of the frequency domains by using the channel state measurement result. The terminal finally sets the radio link quality to “Out-of-sync” (or “bad”, hereinafter same) or “In-sync” (or “normal”, based on the quality evaluation result for each of the frequency domains). The same applies to the following). The terminal transmits the frequency domain quality information derived by performing radio link quality evaluation to the base station. Then, the base station receives the frequency domain quality information from the terminal and utilizes the control channel and data channel allocation for the terminal.

In this case, for radio link monitoring, a base station determines at least one setting of at least one frequency domain that is divided within a downlink channel band, for example, the size of each frequency domain and the number of frequency domains in the downlink channel band are determined by a base station. Control) or other signaling to inform the UE. As another method, by using a predetermined configuration between the base station and the terminal, separate signaling for frequency domain configuration that is divided within the downlink channel band may not be required for the radio link monitoring. Alternatively, the terminal may determine the frequency domain setting that is divided in the downlink channel band for radio link monitoring and inform the base station of the related information. As the criterion for setting the frequency domain, various criteria, such as downlink and uplink channel bandwidth, base station traffic load, base station type, and terminal type, may be applied, but are not necessarily limited to these factors.

In addition, when the base station supports a method of transmitting through a plurality of carriers such as carrier aggregation (CA), which is a carrier combining technique, the frequency domain for monitoring the radio link is not distinguished only within the downlink channel band of one carrier, but is transmitted to the CA. It can be extended to be divided within the entire downlink channel band of the available multiple carriers. For example, if the base station can use the N carriers in the CA, the base station may be configured to divide the frequency domain into N sub-units having a downlink channel bandwidth of each carrier. Alternatively, radio link monitoring may be performed only for downlink channel bands of some of N carriers. The size of the frequency domain division unit may be freely set to correspond to a part of the downlink bandwidth of each carrier or the downlink bandwidth of each carrier. In addition, the size and number of frequency domain division units for each carrier may be set differently. The frequency domain quality information according to an embodiment of the present invention may be a frequency domain having at least one or more reliable quality or at least one or more unreliable quality. It may include information on the frequency domain having a. Alternatively, the frequency domain quality information may include information indicative of at least one value of quality for each frequency domain, wherein the value may be expressed as an absolute value or a difference with respect to a specific reference quality value. As described above, the frequency domain quality information may be utilized to allocate a control channel and a data channel to a corresponding terminal.

Hereinafter, in the present invention, the terminal performs radio link quality evaluation for each of at least one or more frequency domains divided within the downlink channel band configured for the radio link monitoring.

2 is a diagram illustrating a method of dividing a downlink channel band into at least one frequency region for monitoring a radio link in a wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the downlink channel bandwidth is divided into three frequency domains (sub-bands), and the three frequency domains are divided into sub-band 0 (200), sub-band 1 (201), and sub- bands, respectively. Expressed as band 2 (202).

In order to evaluate the radio link quality, the terminal acquires an average level for each frequency domain by using channel state measurement values from the channel state information reference signals included in the divided frequency domains as shown in FIG. 2. The terminal filters the obtained level for each frequency domain and compares the level with a threshold Q_out 203 (or a first reference value, which is the same below).

The average level 204 for the sub-band 0 (200) is higher than the Q_out 203, but the average level 205 of the sub-band 1 201 is lower than the Q_out 203 and the sub-band 2 (202). It can be seen that the average level 206 is higher than the Q_out 203. In other words, the frequency domain of Sub-band 1 201 has unreliable quality, whereas the quality of frequency domain of Sub-band 0 200 and Sub-band 2 202 is not degraded to an unreliable level. It means state. FIG. 2 of the present embodiment shows a case in which the terminal compares the average levels 204, 205, and 206 of each frequency domain with Q_out. However, the terminal shows the average levels 204, 205 of each frequency domain. ), 206 can be compared with Q_in as well as Q_out. More specifically, the terminal compares the average level of each frequency domain with Q_out when evaluating whether the out-of-sync of the radio link quality. On the other hand, when the UE evaluates the in-sync of the radio link quality, the terminal compares the average level of each frequency domain with Q_in.

In the present invention, without limiting the size of each divided frequency domain, it can be set to various sizes. For example, the size of the divided frequency domain corresponds to the frequency resource size (6/15/25/50/75/100) corresponding to the channel bandwidth (1.4 MHz / 3 MHz / 5 MHz / 10 MHz / 15 MHz / 20 MHz) that can be supported in the LTE system. RB) may be set to an appropriate value. Here, RB (Resource Block) is a frequency resource allocation unit of the LTE RB is composed of 12 subcarriers, and has a size of 180kHz.

3 is a flowchart illustrating a procedure of performing radio link quality estimation by a terminal in a wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 3, in step 300, the UE performs measurement and evaluation based on the channel state information reference signal (CSI-RS) for each set frequency region. Thereafter, in step 301, the terminal determines whether the evaluation result for all frequency domains is lower than Q_out. If the evaluation result for all frequency domains is lower than Q_out, the terminal determines in step 302 the radio link quality evaluation result as “out-of-sync”. This is because there is no space in the downlink channel band that can be provided smoothly because there is no frequency domain with a quality enough to be provided with the service.

On the other hand, if the evaluation result of at least one frequency domain is higher than Q_out, the terminal returns to step 300 without determining “out-of-sync” and continuously performs radio link monitoring. This is to make the best use of these frequency ranges while maintaining the radio link when there are at least one frequency region having a quality enough to receive service from the base station in the downlink channel band. For example, the terminal may then transmit information on the frequency domain (quality information for each frequency domain) having a quality that can provide a service from the base station to the base station. Then, the base station can make full use of the frequency domain by assigning resources to the frequency domain.

In addition to the above-described method for evaluating the radio link quality, the present invention may be implemented in various ways. For example, if there is at least one evaluation result for each frequency region lower than Q_out, the terminal may make an “out-of-sync” determination, or otherwise, the radio link monitoring may be continued without making a determination.

FIG. 4 is a flowchart illustrating another procedure of evaluating a radio link quality by a terminal in a wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 4, in step 400, the terminal performs measurement and evaluation based on the channel state information reference signal for each set frequency region. Thereafter, in step 401, the UE checks whether there is a higher than Q_in among evaluation results for the frequency domain. If there is at least one evaluation result for the frequency region higher than Q_in, the terminal determines in step 402 the radio link quality evaluation result as "In-sync". This is advantageous when the terminal enters the physical layer abnormality detection state, and the evaluation result of at least one frequency domain is determined to be normal, so as to recover the state of the terminal as quickly as possible. If the evaluation result for all frequency domains is lower than Q_in, the terminal returns to step 400 without performing “In-sync” determination and continues to perform radio link monitoring.

In addition to the above-described method for evaluating the radio link quality, the present invention may be implemented in various ways. For example, if the evaluation result for each frequency domain is higher than Q_in, the UE may make an “Out-of-sync” decision or otherwise perform radio link monitoring without making a decision.

As described above, the terminal performs frequency domain based radio link quality evaluation, and as a result, the terminal acquires quality information for each frequency domain. The terminal transmits the frequency domain quality information obtained in the frequency domain based radio link quality evaluation to the base station so that the base station can allocate a downlink resource for the terminal in a frequency domain having a quality that allows smooth service.

Here, the terminal requests uplink resource allocation to the base station to transmit frequency domain quality information. For example, the terminal may transmit a scheduling request to the base station in uplink or transmit a random access preamble.

Then, the base station may receive the scheduling request and transmit uplink resource allocation information for the corresponding request in downlink to the terminal. Alternatively, the base station may receive a random access preamble and transmit a random access response including uplink resource allocation information to the terminal. Accordingly, the terminal can transmit the frequency domain quality information of the terminal through the uplink resources allocated from the base station using the above methods.

If the evaluation results of all frequency domains are the same in the frequency domain-based radio quality estimation of the terminal, the terminal may not perform the operation for receiving the aforementioned uplink resource. For example, if the evaluation result of all frequency domains is higher than Q_out, the UE may not transmit a scheduling request or a random access preamble for transmitting the frequency domain quality information. This is because even if a downlink resource is allocated to any frequency domain, the gain obtained by utilizing the frequency domain quality information will be small since smooth service can be provided.

5 is a flowchart illustrating a procedure in which a terminal transmits frequency domain quality information to a base station in a wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 5, in step 500, the terminal performs frequency domain based radio link quality evaluation. In step 501, the terminal determines whether it is necessary to transmit frequency domain quality information as a result of the evaluation.

If it is determined that the evaluation results of the frequency domains are different and it is necessary to inform the base station of a frequency domain capable of providing a service, the terminal proceeds to step 502 and transmits a scheduling request to the base station. If it is determined that there is no need, the terminal terminates the process of transmitting the frequency domain quality information.

In step 503, the terminal checks whether the requested uplink resource allocation information is received from the base station. If uplink resource allocation information is received, the terminal proceeds to step 504 and transmits frequency domain quality information to the base station through the allocated uplink resources.

If the uplink resource allocation information has not been received, the terminal proceeds to step 505 and performs a full band-based radio link quality evaluation, which is a conventional method, rather than a frequency domain-based quality evaluation. This is because the scheduling request transmitted by the terminal is not normally received by the base station or the uplink resource allocation information transmitted from the base station is not normally received by the terminal and thus the downlink resource allocation gain using the frequency domain quality information is not obtained. It is to perform a full band-based radio link quality assessment.

6 is a flowchart illustrating a procedure according to another embodiment in which a terminal transmits frequency domain quality information to a base station in a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 6, in step 600, the terminal performs frequency domain based radio link quality evaluation. In step 501, the terminal determines whether it is necessary to transmit frequency domain quality information as a result of the evaluation.

If it is determined that the evaluation results of the frequency domains are different and it is necessary to inform the base station of a frequency domain capable of providing a service, the terminal proceeds to step 602 and transmits a random access preamble to the base station. If it is determined that there is no need, the terminal terminates the process of transmitting the frequency domain quality information.

In step 603, the terminal checks whether a random access response transmitted from the base station is received. If the random access response is received, the terminal proceeds to step 604 and transmits the frequency domain quality information to the base station through the allocated uplink resources based on the uplink resource allocation included in the random access response.

If the random access response has not been received, the terminal proceeds to step 605 and performs the conventional full band based radio link quality estimation instead of the frequency domain based quality estimation. This is because the random access preamble transmitted by the mobile station is not normally received by the base station or the random access response transmitted from the base station is not normally received by the mobile station, so that a downlink resource allocation gain using frequency domain quality information cannot be obtained. To perform band-based radio link quality assessment.

FIG. 7 is a diagram illustrating an example in which a terminal inserts frequency domain quality information into a physical uplink shared channel (PUSCH) for transmitting frequency domain quality information to a base station in a wireless communication system according to an embodiment of the present invention.

Here, the PUSCH is a physical channel used by the UE to transmit data in the uplink in the LTE system, and includes channel quality information (CQI), AN (ACK-NACK), and rank indicator (Rank Indicator, RI) in the PUSCH. It is standardized to transmit the same uplink channel information with data.

Referring to FIG. 7, frequency domain quality information transmitted from a mobile station to a base station is denoted by an FB 700 meaning feedback (FedBack), and the FB 700 is inserted as a symbol in the DFT input 701 during a PUSCH transmission process. . Since the data may be rate matched in consideration of the corresponding FB 700 information amount, there is no problem due to the insertion of frequency domain quality information.

RS 702 in the figure is an uplink reference signal, and is used for channel estimation and demodulation when the base station receives a PUSCH. AN 703 represents a Hybrid Automatic Repeat Request (HARQ) ACK-NACK signal. In addition, the RI 704 refers to a rank indicator including rank information for multiple input multiple output (MIMO) transmission of the base station.

In FIG. 7, the AN 703 and the RI 704 are inserted into the PUSCH together with the frequency domain quality information FB 700, but the frequency domain quality information FB (without the AN 703 and the RI 704) is illustrated. Only 700 may be inserted in the PUSCH, and either the AN 703 or the RI 704 and the frequency domain quality information FB 700 may be inserted together in the PUSCH. In addition, data may not exist in the PUSCH including the frequency domain quality information FB 700.

Alternatively, the frequency domain quality information location may be set to be adjacent to the uplink reference signal RS 702 so that the base station has excellent channel estimation accuracy when receiving the frequency domain quality information.

FIG. 8 is a diagram illustrating another example in which a terminal inserts frequency domain quality information into a physical uplink shared channel (PUSCH) for transmitting a frequency domain quality information to a base station in a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 8, CQI 801 (Channel Quality Information) information is present when the frequency domain quality information FB 800 is inserted into a PUSCH. The frequency domain quality information FB 800 corresponds to a CQI 801. ) Is inserted at the next position. Alternatively, the CQI 801 and the frequency domain quality information may be encoded and inserted together.

9 is a block diagram illustrating a configuration of a base station transceiver in a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 9, the base station receives a PUSCH in which frequency domain quality information is inserted from the terminal through the antenna 900 (or the wireless communication unit). The frequency domain quality information may be quality information for each of at least one or more frequency domains divided within a downlink channel band. Specifically, as described above, it may include information on a frequency domain having at least one or more reliable qualities or a frequency domain having at least one or more unreliable qualities. Alternatively, the frequency domain quality information may include information indicative of at least one value of quality for each frequency domain, wherein the value may be expressed as an absolute value or a difference with respect to a specific reference quality value.

The received PUSCH passes through the cyclic prefix removal unit 901, the DFT unit 902, the resource demapping unit 903, and the inverse-DFT unit ID904, and as a result, the frequency domain quality inserted into the PUSCH. Information is separated. The frequency domain quality information is detected by the frequency domain quality information detector 905.

The resource allocation control unit 906 performs downlink resource allocation based on the detected frequency quality region information. The downlink signals for the UE are generated through the downlink control signal generator 907, the downlink data signal generator 908, and the reference signal, that is, the RS signal generator 909. The control signal generated by the downlink control signal generator 907 includes resource allocation related information determined by the resource allocation controller 906. The generated downlink signals are input to the resource mapping unit 910 and mapped to the corresponding resources according to the resource allocation decision of the resource allocation control unit 906. Thereafter, the resource mapping unit 910 output is transmitted to the terminal through the antenna 913 through the inverse fast fourier transform (IFFT) unit 911 and the CP insertion unit 912.

10 is a block diagram illustrating a configuration of a terminal transceiver device in a wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 10, the terminal receives a downlink signal through an antenna 1000 (or a wireless communication unit) constituting a transceiver. Thereafter, the downlink signal is separated from the reference signal, the data channel, and the control channel through the CP removing unit 1001, the FFT unit 1002, and the resource demapping unit 1003.

The channel measurer 1004 performs downlink channel estimation and channel state measurement based on the reference signal. The channel estimation result is used by the data and control signal detector 1005 to detect the data and the control channel. In addition, the channel state measurement result is used by the radio link quality evaluation unit 1006 to perform radio link quality evaluation. According to an exemplary embodiment of the present invention, the channel measuring unit 1004 may measure a channel state using a channel state information reference signal (CSI-RS) or a common reference signal among various types of reference signals. Meanwhile, the wireless link quality evaluator 1006 evaluates the radio link quality as bad when the quality evaluation result for all frequency domains is smaller than the Q-out (first reference value), and evaluates the quality for at least one frequency domain. If the result is larger than Q_out, the wireless link monitoring may be continuously performed without evaluating the radio link quality as bad.

In addition, the radio link quality evaluator 1006 evaluates the radio link quality as normal when the quality evaluation result of at least one or more frequency domains is greater than Q_in (second reference value), and the quality evaluation results of all frequency domains. Is smaller than Q_in, the wireless link monitoring may be continuously performed without evaluating the radio link quality as normal.

When it is necessary to transmit the frequency domain quality information to the base station as a result of the radio link quality evaluation, the frequency domain quality information generating unit 1007 generates frequency domain quality information that the base station can utilize for downlink resource allocation.

The frequency domain quality information generator 1007 may control a series of processes such that the generated frequency domain quality information may be transmitted to the base station. To this end, the frequency domain quality information generation unit 1007 transmits an uplink resource allocation request or a random access preamble to the base station, and the uplink resource allocated by the base station in response to the uplink resource allocation request or the random access preamble. It can be controlled to transmit the quality information for each frequency region to the base station through. When the frequency domain quality information generation unit 1007 does not receive the uplink resource allocation request or the response according to the random access preamble from the base station, the frequency domain quality information generation unit 1007 performs radio link quality evaluation on the entire downlink channel band. It can be controlled to instruct the radio link quality evaluation unit.

In addition, according to an embodiment of the present invention, if the frequency domain quality information generation unit determines that the quality of all frequency domains is good or the quality of all the frequency domains is poor, the frequency domain quality information is transmitted to the base station. You can also control not to.

When the above process is described as a signal flow, the output of the frequency domain quality information generation unit 1007 enters the DFT unit 1008 and is inserted into the PUSCH. In the resource mapping unit 1009, the PUSCH including the frequency domain quality information is mapped to the corresponding resource according to the resource allocation information obtained by the data and control signal detection unit 1005. Thereafter, the output of the resource mapping unit 1009 is transmitted to the base station through the antenna 1012 via the IDFT unit 1010 and the CP insertion unit 1011.

11 is a flowchart illustrating an operation procedure of a base station in a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 11, the base station may first receive an uplink resource allocation request transmitted from the terminal. As described above, the uplink resource allocation request of the terminal may be performed through a scheduling request or a random access preamble.

Then, in step 1100, the base station allocates uplink resources to the terminal in response to the uplink resource allocation request from the terminal. In step 1101, the base station receives frequency domain quality information received through the uplink resource allocated to the terminal from the terminal. In step 1102, the base station performs downlink resource allocation to the corresponding terminal based on the received frequency domain quality information. The base station then terminates the algorithm according to the invention.

12 is a flowchart illustrating an operation procedure of a terminal in a wireless communication system according to an embodiment of the present invention.

 Referring to FIG. 12, in step 1200, the terminal performs frequency domain based radio link quality estimation based on a channel measurement result obtained from a downlink reference signal received from a base station.

The process may include measuring a channel state for each of at least one frequency domain divided within a downlink channel band, evaluating quality for each of the frequency domains using the measurement result, The step of evaluating the radio link quality based on the quality evaluation result can be more specifically subdivided.

In step 1201, the terminal determines whether it is necessary to transmit frequency domain quality information as a result of the evaluation of step 1200. If it is determined that it is necessary to inform the base station of the frequency domain quality information, the terminal proceeds to step 1202 and transmits an uplink resource allocation request to the base station. As described above, the terminal may transmit a scheduling request or a random access preamble to the base station for the resource allocation request. On the other hand, if the terminal determines that transmission of the frequency domain quality information is not necessary, the terminal terminates the algorithm according to the present invention. .

Meanwhile, in step 1203, the terminal checks whether uplink resource allocation information requested by the base station has been received.

If the uplink resource allocation information is received, the terminal proceeds to step 1204 and transmits the frequency domain quality information to the base station through the allocated uplink resources. If the uplink resource allocation information has not been received, the UE proceeds to step 1205 and the UE performs the entire band-based radio link quality evaluation instead of the frequency domain-based quality evaluation. The terminal then terminates the algorithm according to the present invention.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

Claims (14)

In the method of the terminal of a wireless communication system,
Receiving configuration information including a plurality of frequency domains for radio link monitoring;
Identifying at least one frequency domain in the plurality of frequency domains;
Measuring radio link quality based on a reference signal in the at least one frequency domain; And
Indicating, by the physical layer of the terminal, an in-sync or out-of-sync of the radio link quality of the at least one frequency band to an upper layer,
The plurality of frequency domains are included in a downlink band,
The setting information includes location and bandwidth information of each frequency domain. The method of claim 1, wherein when the evaluation result of the radio link quality of at least one of the resources for monitoring the radio link is higher than a first threshold, the in-sync is indicated to the upper layer. How to. The method of claim 1, wherein the out-of-sync is indicated to the upper layer when the evaluation result of the radio link quality of all resources among the resources for monitoring the radio link is lower than a second threshold value. How to. The method of claim 1, wherein when a plurality of carriers are configured in the terminal, the radio link monitoring is performed in a plurality of frequency domains included in the plurality of carriers. The method of claim 1,
Confirming whether an out-of-sync instruction is continuously generated more than a first number of times; And
And when the out-of-sync indication occurs more than the first number of times, confirming that a physical layer problem is detected and initiating a timer operation. The method of claim 5,
Checking whether an in-sync instruction has been continuously generated for a second or more times while the timer is running;
And confirming that the physical layer abnormality has recovered when the in-sync indication occurs continuously for more than the second number of times. The method of claim 1, wherein the reference signal is a channel state information reference signal. In a terminal of a wireless communication system,
A transceiver; And
Receives configuration information including a plurality of frequency domains for wireless link monitoring, identifies at least one frequency domain in the plurality of frequency domains, and measures radio link quality based on reference signals of the at least one frequency domain. Doing; And a control unit connected to the transceiver for controlling the physical layer of the terminal to instruct in-sync or out-of-sync of the radio link quality of the at least one frequency band to an upper layer. ,
The plurality of frequency domains are included in a downlink band,
The setting information includes a location and bandwidth information of each frequency domain. The method of claim 8, wherein when the evaluation result of the radio link quality of at least one of the resources for the radio link monitoring is higher than the first threshold value, the in-sync is indicated to the upper layer. Terminal. The method of claim 8, wherein the out-of-sync is indicated to the upper layer when the evaluation result of the radio link quality of all resources among the resources for monitoring the radio link is lower than a second threshold value. Terminal. The terminal of claim 8, wherein when a plurality of carriers are configured in the terminal, the radio link monitoring is performed in a plurality of frequency domains included in the plurality of carriers. The method of claim 8, wherein the controller is further configured to determine whether an out-of-sync instruction is continuously generated more than the first number of times, and if the out-of-sync instruction is generated more than the first number of times, The terminal characterized in that the physical layer problem is detected and further controls to start the timer operation. The method of claim 12, wherein the controller is further configured to determine whether an in-sync instruction is continuously generated for a second time or more while the timer is operating, and wherein the in-sync instruction is continuously for more than the second number of times. The terminal, characterized in that further control to confirm that the physical layer abnormality has recovered. The terminal of claim 8, wherein the reference signal is a channel state information reference signal.

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