KR102575361B1 - Base station and control method thereof - Google Patents

Abstract

The present invention relates to a base station and a control method thereof. In the method for controlling a base station according to the present invention, the steps of receiving a Sounding Reference Signal (SRS) signal and an Uplink Demodulation Reference Signal (UL DMRS) signal from a user terminal; calculating an evaluation value considering both the received SRS signal and the UL DMRS signal; comparing the calculated evaluation value with a preset reference value and selecting a Modulation and Coding Scheme (MCS) based on the difference; and controlling so that uplink communication is performed based on the selected MCS.

Description

Base station and its control method {BASE STATION AND CONTROL METHOD THEREOF}

The present invention relates to a base station and a control method thereof, and more particularly, to a 5G base station and a control method thereof for selecting an appropriate MCS even when an SRS is not normally received.

In operating a mobile communication network, a predetermined reference signal RS (Reference Signal) signal must be exchanged between a terminal and a base station.

In other words, RS is a predefined signal emitted from the transmitter for a specific purpose and is mainly used for 'channel estimation'.

For example, which RS is defined depends on whether it is LTE (4G communication) or NR (5G communication).

For example, CSI-RS (Channel State Information - Reference Signal) is an RS for finding out the state of a channel that a gNodeB (gNB) sends downlink to a user equipment (UE).

To this end, when a gNB creates a CSI-RS and sends the CSI-RS, the UE looks at the CSI-RS, identifies the channel situation, and reports the result to the gNB. Methods and algorithms for identifying channel conditions are standardized as disclosed in TS 38.211.

In addition, a sounding reference signal (SRS) corresponds to a reference signal signal in which the subject transmitting the CSI-RS and the subject receiving the CSI-RS are opposite.

That is, when the UE transmits to the gNB to check the status of the uplink channel sent to the gNB, the gNB reports to the UE based on the current channel status and reflects it in the future UL.

In particular, the UE transmits the SRS with beams in multiple directions, and the gNB identifies the channel conditions in each direction based on the received SRS, and based on this, it determines which beam to use or the rank of the uplink channel. It transmits information necessary for (Uplink Channel) to the UE.

In this process, it can be said that the gNB (base station) selects a Modulation Coding Scheme (MCS) and controls uplink communication based on the selected MCS. For example, it may be configured in the form of a kind of table consisting of a combination of each variable.

However, conventionally, when selecting an MCS, there is a case in which an appropriate MCS cannot be selected by relying only on the SRS signal.

For example, when the UE transmits the SRS signal, due to various problems such as measurement gap and UL power shortage, the priority is lost and the base station cannot properly transmit the SRS at the expected time. In this case, the base station may select an inappropriate MCS by erroneously determining that the SRS SINR (Signal to Interference plus Noise Ratio) is very low without recognizing that the SRS was not transmitted at all by the UE.

Registered Patent No. 10-2268939

The present invention has been made to solve the above conventional problems, and its object is to provide a base station and a control method for selecting an MCS with minimized errors even in a situation where an SRS is not properly transmitted from a user terminal.

In order to achieve the above object, a control method of a base station according to the present invention includes the steps of receiving a Sounding Reference Signal (SRS) signal and an Uplink DeModulation Reference Signal (UL DMRS) signal from a user terminal; calculating an evaluation value considering both the received SRS signal and the UL DMRS signal; comparing the calculated evaluation value with a preset reference value and selecting a Modulation and Coding Scheme (MCS) based on the difference; and controlling so that uplink communication is performed based on the selected MCS.

Here, an evaluation value corresponding to the sum of the SINR of the SRS signal and the SINR of the UL DMRS signal may be calculated.

Here, when the calculated evaluation value is greater than the preset reference value, the MCS is selected based on the SINR of the SRS signal, and when the calculated evaluation value is not greater than the preset reference value, the MCS is selected based on the SINR of the UL DMRS signal. can

Here, the step of determining a strong electric field state or a weak electric field state using a signal received from the user terminal, and when the strong electric field state is determined, the full-band SRS signal and the UL DMRS signal together Taking into account the above evaluation value can be calculated.

Here, when the weak electric field state is determined, the evaluation value may be calculated by considering both the sub-band SRS signal and the UL DMRS signal.

In addition, a base station according to the present invention in order to achieve the above object, in the base station, a signal receiving unit for receiving a sounding reference signal (SRS) signal and an uplink demodulation reference signal (UL DMRS) signal from a user terminal; an evaluation value calculating unit calculating an evaluation value considering both the SRS signal and the UL DMRS signal received by the signal receiving unit; an MCS selection unit that compares the evaluation value calculated by the evaluation value calculation unit with a preset reference value and selects a Modulation and Coding Scheme (MCS) based on the difference; A communication control unit controlling uplink communication to be performed based on the MCS selected by the MCS selection unit may be included.

Here, the evaluation value calculation unit may calculate an evaluation value corresponding to the sum of the SINR of the SRS signal and the SINR of the UL DMRS signal.

Here, the MCS selection unit selects an MCS based on the SINR of the SRS signal when the evaluation value calculated by the evaluation value calculation unit is greater than the preset reference value, and the evaluation value calculated by the evaluation value calculation unit is greater than the preset reference value. If it is not large, the MCS may be selected based on the SINR of the UL DMRS signal.

Here, further comprising a communication environment determination unit for determining a strong electric field state or a weak electric field state using a signal received from the user terminal, and when the communication environment determination unit determines that the strong electric field state, the evaluation value calculation unit full-band ( The evaluation value may be calculated by considering both the full-band) SRS signal and the UL DMRS signal.

Here, when the communication environment determination unit determines that the electric field is weak, the evaluation value calculation unit may calculate the evaluation value by considering both the sub-band SRS signal and the UL DMRS signal.

As described above, according to the present invention, by determining based on the evaluation value considering the SRS signal and the UL DMRS signal together, due to various problems such as measurement gap and UL power shortage in the user terminal Even when the SRS signal is not properly transmitted due to a high priority, the base station can select an appropriate MCS, and thus the uplink communication quality can be improved.

1 is a schematic configuration diagram of an entire communication system including a base station according to an embodiment of the present invention;
2 is a functional block diagram of the user terminal of FIG. 1;
3 and 4 are control flow diagrams of a base station according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, each embodiment according to the present invention is only one example to aid understanding of the present invention, and the present invention is not limited to these embodiments. In particular, the present invention may be composed of at least one or more combinations of individual components, individual functions, or individual steps included in each embodiment.

In particular, although alphabets such as '(a)' are included in some claims of the claims for convenience, these alphabets do not prescribe the order of each step.

A schematic configuration of the entire communication system including the base station 100 according to an embodiment of the present invention is as shown in FIG.

In the same figure, the user terminal 200 is used by communication subscribers who want to communicate with the other party or the server 300 on the network, and may correspond to, for example, a smart phone.

The user terminal 200 performs wireless communication by forming a communication channel with the base station 100. At this time, various signals or reports necessary for selecting an appropriate communication channel can be exchanged with the base station 100.

For example, when the user terminal 200 is a 5G (Fifth Generation) terminal, it may transmit a Sounding Reference Signal (SRS) signal and an Uplink Demodulation Reference Signal (UL DMRS) signal to the base station 100.

In addition, the user terminal 200 may measure Reference Signals Received Power (RSRP) for a reference signal on a Physical Uplink Control Channel (PUCCH)/Physical Uplink Shared Channel (PUSCH) and transmit the result to the base station 100.

As such, the process of transmitting and receiving the user terminal 200 to and from the base station 100 for determining the communication environment, selecting an appropriate communication channel, etc. corresponds to a known technology, and thus a detailed description thereof will be omitted.

The base station 100 establishes a communication channel with the user terminal 200 and transmits communication signals/data transmitted by the user terminal 200 through the formed communication channel to its destination.

In this embodiment, the 'base station 100' includes a repeater necessary for signal transmission.

In particular, the base station 100 may correspond to 5G New Radio (NR), which is a radio access technology (RAT) defined by 3GPP for a 5G (5th generation) mobile network.

Here, the meaning of forming a communication channel includes a process of selecting and exchanging not only a communication frequency but also beam direction (SRS Index), rank, transmit precoding information for uplink, and the like.

In particular, as described above, the base station 100 may transmit and receive a predetermined reference signal (RS) to establish an appropriate communication channel with the user terminal 200.

An example of a specific functional block of the base station 100 is as shown in FIG. 2 .

As shown in the same figure, it may include a signal receiving unit 110, an evaluation value calculating unit 120, an MCS selection unit 130, a communication control unit 140, and a communication environment determining unit 150.

First, the communication environment determination unit 150 performs a function of determining a strong electric field state or a weak electric field state using a signal received from the user terminal 200 .

That is, it is possible to determine whether the communication quality is in a strong electric field state or a weak electric field state. For this purpose, the communication environment determining unit 150 may determine such a communication environment by its own algorithm, or the user terminal The communication environment may be determined by receiving RSRP (Reference Signal Received Power) determined by step 200.

The signal receiving unit 110 performs a function of receiving a Sounding Reference Signal (SRS) signal and an Uplink Demodulation Reference Signal (UL DMRS) signal from the user terminal 200 .

Here, the SRS signal is a reference signal transmitted by the user terminal 200 for the status or selection of an uplink channel, as mentioned in the background art.

In addition, a demodulation reference signal (DMRS) signal is a reference signal for estimating a channel value necessary for demodulating data. DMRS can be transmitted regardless of downlink (DL) and uplink (UL), but in this embodiment, only the case of uplink is considered.

The evaluation value calculating unit 120 performs a function of calculating an evaluation value considering both the SRS signal and the UL DMRS signal received by the signal receiving unit 110 .

For example, the evaluation value calculating unit 120 may calculate a sum of the signal to interference plus noise ratio (SINR) of the SRS signal and the SINR of the UL DMRS signal as an evaluation value.

In particular, when the above-mentioned communication environment determining unit 150 determines that a strong electric field is present, the evaluation value calculating unit 120 may calculate an evaluation value in consideration of a full-band SRS signal and a UL DMRS signal.

On the other hand, when the communication environment determination unit 150 determines that the electric field is weak, the evaluation value calculation unit 120 may calculate an evaluation value in consideration of the sub-band SRS signal and the UL DMRS signal.

That is, the type of signal used to calculate the evaluation value in the evaluation value calculation unit 120 is different depending on whether it is in a strong electric field state or a weak electric field state.

Here, the full-band means the entire available band, and the sub-band means a part of the available band. For reference, it is generally desirable to transmit the SRS signal over all bands, but in this case, the reach is short It has the advantage of being longer.

The MCS selection unit 130 compares the evaluation value calculated by the evaluation value calculation unit 120 with a preset reference value and selects a Modulation and Coding Scheme (MCS) based on the difference.

Selecting an MCS means, in this embodiment, that a specific MCS is selected so that appropriate uplink communication can be performed. The MCS corresponds to a combination of various parameters required for communication, and is configured in the form of a table consisting of combinations of each variable, for example. It has been mentioned above that it may be, and since the configuration of the MCS itself corresponds to a known technology, a detailed description thereof will be omitted.

However, in the prior art, if the base station 100 relied only on the SRS signal in selecting the MCS, in this embodiment, the MCS is selected based on the evaluation value, and the evaluation value here is a value considering both the SRS signal and the UL DMRS signal (especially , a value corresponding to the sum of the SINR of the SRS signal and the SINR of the UL DMRS signal).

In particular, the MCS selection unit 130 selects the MCS based on the SINR of the SRS signal when the evaluation value calculated by the evaluation value calculation unit 120 is greater than the preset reference value, and If the evaluation value is not greater than the preset reference value, the MCS may be selected based on the SINR of the UL DMRS signal.

Here, the MCS selector 130 does not need to check whether the SRS signal and the UL DMRS signal are actually transmitted by the user terminal 200, but after controlling the transmission of the SRS signal and the UL DMRS signal, the corresponding signals Assuming that it is transmitted by the terminal 200, the evaluation value calculated by adding the SINR values of the received signals is compared with a preset reference value, and based on the result, the MCS is selected based on the SINR of the SRS signal or the UL DMRS signal Selecting the MCS based on the SINR.

The communication controller 140 performs a function of controlling uplink communication based on the MCS selected by the MCS selector 130.

For example, the communication control unit 140 can transmit information on the MCS selected by the MCS selection unit 130 to the user terminal 200 and control communication to be performed based on the selected MCS.

That is, the user terminal 200 can perform communication after setting the beam direction (SRS Index), rank, transmit precoding information for uplink, etc. based on the received MCS.

Since the process itself of controlling the user terminal 200 to perform uplink communication based on the selected MCS by the base station 100 corresponds to a well-known technique, a detailed description thereof will be omitted.

Hereinafter, a control flow of the base station 100 according to an embodiment of the present invention will be described with reference to FIGS. 3 and 4.

First, referring to FIG. 3 as follows.

The base station 100 receives the SRS signal and the UL DMRS signal from the user terminal 200 (step S1).

Here, transmission of the SRS signal and the UL DMRS signal by the user terminal 200 may be performed by request or control of the base station 100 .

The base station 100 determines the SINR of the SRS signal received from the user terminal 200 (step S3) and also determines the SINR of the UL DMRS signal received from the user terminal 200 (step S5).

Determining the SINR of the received signal itself corresponds to a known technique, and thus a detailed description thereof will be omitted.

Subsequently, the base station 100 calculates an evaluation value by adding the SINR of the SRS signal and the SINR of the UL DMRS signal (step S7).

In addition, the base station 100 compares the calculated evaluation value with a preset reference value (step S9), and when the comparison result evaluation value is greater than the reference value, the base station 100 selects an MCS based on the SINR of the SRS signal (step S11 ).

When the comparison result evaluation value is less than or equal to the reference value (step S9), the base station 100 selects the MCS based on the SINR of the UL DMRS (step S13).

Next, referring to FIG. 4 , processing according to strong/weak electric field conditions will be described.

The base station 100 determines the communication environment state (step S21). That is, it is determined whether it is in a strong electric field state or a weak electric field state.

Here, whether it is a strong electric field state or a weak electric field state may be determined by, for example, RSRP received from the user terminal 200 .

As a result of the determination, when the strong electric field state (step S23), the base station 100 considers the full-band SRS signal and the UL DMRS signal together and selects the MCS (step S25). For example, in the case of a weak electric field state) (step S23), the MCS is selected by considering both the sub-band SRS signal and the UL DMRS signal (step S27).

Here, the process of selecting the MCS by considering both the SRS signal and the UL DMRS signal is the same as that described in FIG. 3, so redundant description is omitted.

Next, the base station 100 controls the user terminal 200 to perform uplink communication using the selected MCS (step S29).

Although not specifically mentioned in the above-described embodiment, the base station 100 may additionally request a transmission method of the SRS signal from the user terminal 200 for processing according to the strong electric field/weak electric field situation.

For example, the base station 100 may request the user terminal 200 to transmit the SRS signal in full-band in the case of a strong electric field state, and in the case of a weak electric field state, the SRS signal may be transmitted in a sub-band (sub-band) -band) can be requested.

That is, in response to such a request, the user terminal 200 transmits the SRS signal through an appropriate band, and the base station 100 uses the received SRS signal to determine an appropriate MCS by considering it together with the UL DMRS signal as described above. you can choose

Meanwhile, it goes without saying that the process of performing each of the above-described embodiments may be performed by a program or application stored in a predetermined recording medium (for example, computer-readable). Here, the recording medium includes all of an electronic recording medium such as RAM (Random Access Memory), a magnetic recording medium such as a hard disk, an optical recording medium such as a CD (Compact Disk), and the like.

At this time, the program stored in the recording medium may be executed on hardware such as a computer or smart phone to perform each of the above-described embodiments. In particular, at least one of the functional blocks of the base station 100 according to the present invention described above may be implemented by such a program or application.

In addition, the present invention is not limited to the specific embodiment described above, but can be implemented by various modifications and variations within the scope of the present invention. It will be apparent that such variations and modifications are included in the present invention provided they come within the scope of the appended claims.

100: base station 200: user terminal
110: signal receiving unit 120: evaluation value calculating unit
130: MCS selection unit 140: communication control unit
150: communication environment determination unit

Claims (12)

(a) receiving a Sounding Reference Signal (SRS) signal and an Uplink Demodulation Reference Signal (UL DMRS) signal from a user terminal;
(b) calculating an evaluation value considering both the SRS signal and the UL DMRS signal received in step (a);
(c) comparing the evaluation value calculated in step (b) with a preset reference value, and selecting a Modulation and Coding Scheme (MCS) based on the difference;
(d) controlling so that uplink communication is performed based on the MCS selected in step (c);
In the step (b), an evaluation value is calculated using a sum operation of the SINR of the SRS signal and the SINR of the UL DMRS signal. delete According to claim 1,
In the step (c), when the evaluation value calculated in the step (b) is greater than the preset reference value, the MCS is selected based on the SINR of the SRS signal, and the evaluation value calculated in the step (b) is greater than the preset reference value. A control method of a base station, characterized in that the MCS is selected based on the SINR of the UL DMRS signal when it is not large. According to claim 3,
(e) further comprising determining a strong electric field state or a weak electric field state using a signal received from the user terminal;
In step (b), when it is determined that the state is in a strong electric field state in step (e), the evaluation value is calculated by considering both the full-band SRS signal and the UL DMRS signal. Control method of a base station. According to claim 4,
When it is determined that the electric field is weak in step (e), in step (b), the evaluation value is calculated by considering both the sub-band SRS signal and the UL DMRS signal. Control method of a base station, characterized in that . A computer readable recording medium recording a program for executing the method of any one of claims 1, 3 to 5. An application program stored in a computer readable recording medium to be combined with hardware to execute the method of any one of claims 1, 3 to 5. a signal receiver for receiving a sounding reference signal (SRS) signal and an uplink demodulation reference signal (UL DMRS) signal from a user terminal;
an evaluation value calculating unit calculating an evaluation value considering both the SRS signal and the UL DMRS signal received by the signal receiving unit;
an MCS selection unit that compares the evaluation value calculated by the evaluation value calculation unit with a preset reference value and selects a Modulation and Coding Scheme (MCS) based on the difference;
A communication control unit for controlling uplink communication to be performed based on the MCS selected by the MCS selection unit;
The base station, characterized in that the evaluation value calculation unit calculates the evaluation value using a sum operation of the SINR of the SRS signal and the SINR of the UL DMRS signal. delete According to claim 8,
The MCS selection unit selects an MCS based on the SINR of the SRS signal when the evaluation value calculated by the evaluation value calculation unit is greater than the preset reference value, and the evaluation value calculated by the evaluation value calculation unit is not greater than the preset reference value In this case, the base station characterized in that the MCS is selected based on the SINR of the UL DMRS signal. According to claim 10,
Further comprising a communication environment determination unit for determining a strong electric field state or a weak electric field state using a signal received from the user terminal;
Wherein the evaluation value calculation unit calculates the evaluation value by considering both the full-band SRS signal and the UL DMRS signal when the communication environment determination unit determines that the strong electric field is present. According to claim 11,
The base station, characterized in that, when the communication environment determination unit determines that the electric field state is weak, the evaluation value calculation unit calculates the evaluation value by considering both the sub-band SRS signal and the UL DMRS signal.