KR20160091792A - Method and apparatus for estimating communication quality based on channel status estimation - Google Patents

Abstract

A communication quality prediction method and apparatus are provided. In an environment providing a high-speed communication service utilizing a high-frequency band to a terminal, the strength of a received signal is measured every preset measurement period. Calculates a channel quality degradation parameter for a communication channel between the UE and the base station based on the strength of the received signal, and compares the channel quality degradation parameter with a preset threshold value. If the channel quality degradation parameter is greater than or equal to the threshold value, it is determined that the quality of the communication channel is drastically degraded.

Description

[0001] The present invention relates to a method and apparatus for estimating communication quality based on channel state prediction,

The present invention relates to a communication quality prediction method and apparatus therefor.

In recent years, there has been a rapid increase in demand for high-speed communication services for users, and a communication service and an existing macro area service for providing a very high transmission rate to wireless communication users utilizing a higher- There is an active research on a local communication service aiming at providing a communication service with a relatively high data rate to a user located in a corresponding service area by limiting an extremely narrow area to a service object.

In the case of such a service, the communication environment of the user is seriously changed compared to the existing communication service due to the characteristics of the high frequency band to be used and the environmental characteristic of the communication in which the user is located, such as the city center. This phenomenon can be attributed to signal discontinuity, diffraction, reflection, etc., caused by the surrounding environment in which the user is located and by other objects present in the communication channel between the user and the base station. That is, it can be said that the change in the communication quality is greatly affected not only by the environmental factors such as the geographical characteristic of the user himself, but also by the surrounding factors such as other moving objects surrounding the user.

It can be seen that the environmental or peripheral influence is higher as the utilized frequency becomes higher, and the service quality of the communication cell or sector belonging to a single service area is rapidly changed according to the user's location and surrounding environment .

The general communication connection and quality maintenance measure measures the received signal strength for the user communication and recognizes that a problem has occurred in the communication of the user when the corresponding strength has decreased to a certain level or less. It is recognized as a communication quality degradation. If it is recognized that the communication quality is deteriorated, an adjustment process such as beam searching and beam tracking for tracking an optimal service path in the case of a beam forming service may be performed, A radio link failure (RLF) recovery or a handover procedure is performed to cope with the degradation of the communication quality.

However, in a situation where communication quality deterioration occurs rapidly, if it is determined that the communication quality deterioration has continued for a predetermined problem duration after recognizing the degradation of the communication quality, and a corresponding procedure for the problem is performed, There is a high possibility that it will be lowered to a certain level or less to be performed. As a result, it is difficult to ensure smooth communication service, and in the worst case, it is highly likely to cause communication disconnection.

For example, in the case of an RLF situation in which a physical channel is disconnected in LTE (Long Term Evolution), it is determined that a problem occurs in a communication channel when an out-of-sync situation Q10 occurs. If such a problem situation persists for a preset T310 time, it is determined to be RLF and a corresponding procedure for the problem is performed. That is, when the communication environment is suddenly degraded due to environmental and peripheral changes while a user is stably providing a high-speed communication service in a very high frequency communication service, It is difficult to maintain the communication quality of the communication network, and furthermore, communication disconnection is difficult to cope with.

SUMMARY OF THE INVENTION The present invention is directed to a method for providing a user with a high-speed communication service utilizing a relatively high frequency band by tracking a channel environment of a user and estimating and predicting sudden degradation of communication quality through the channel environment, .

According to an aspect of the present invention, there is provided a method for predicting a communication channel quality in an environment for providing a terminal with a high-speed communication service utilizing a high frequency band, the method comprising: measuring a strength of a received signal at every predetermined measurement period; Calculating a channel quality deterioration parameter for a communication channel between the terminal and the base station based on the strength of the received signal; Comparing the channel quality degradation variable with a preset threshold; And determining that the quality of the communication channel is drastically degraded if the channel quality degradation variable is greater than or equal to the threshold value.

의 조건에 따라 산출될 수 있다. 여기서,

는

을 만족하는 값이며,

는 신호를 수신하는 지점(또는 수신단)과 전송점(또는 송신단) 사이의 거리를 나타내고,

는 기준 거리를 나타낸다. The channel quality degradation variable k is

Can be calculated according to the conditions of < RTI ID = 0.0 > here,

The

, ≪ / RTI >

Represents a distance between a point (or a receiving end) at which a signal is received and a transmission point (or a transmitting end)

Represents the reference distance.

The prediction method may further include determining that the quality of the communication channel is maintained in a normal state when the channel quality degradation variable is smaller than the threshold value.

The method may further include performing quality reduction countermeasure processing when it is determined that the quality of the communication channel is rapidly deteriorated.

The corresponding processing may include adjusting the connection beam or performing the beam searching and tracking process for the candidate beam early, RLF (radio link failure) recovery, or RLF recovery after a problem occurs in a handover procedure or handover decision Setting the time for maintaining the current state to be shorter than a predetermined time, and reflecting the predicted channel environment change information to the user channel configuration and the system setting.

According to another aspect of the present invention, there is provided an apparatus for predicting a communication channel quality in an environment for providing a terminal with a high-speed communication service utilizing a high frequency band, the apparatus comprising: a radio frequency converter for transmitting / receiving a signal through an antenna; And estimating the communication channel quality, the processor comprising: a received signal measuring unit for measuring an intensity of a received signal at every preset measurement period through the RF transceiver; A channel quality degradation variable calculation unit for calculating a channel quality degradation parameter for a communication channel between the UE and the base station based on the strength of the received signal; And a quality predicting unit for comparing the channel quality degradation variable with a preset threshold value and determining that the quality of the communication channel is drastically degraded if the channel quality degradation parameter is greater than or equal to the threshold value.

의 조건에 따라 산출될 수 있으며, 여기서,

는

을 만족하는 값이고,

는 신호를 수신하는 지점(또는 수신단)과 전송점(또는 송신단) 사이의 거리를 나타내고,

는 기준 거리를 나타낸다. The channel quality degradation variable k is

, Where < RTI ID = 0.0 >

The

, ≪ / RTI >

Represents a distance between a point (or a receiving end) at which a signal is received and a transmission point (or a transmitting end)

Represents the reference distance.

The quality predicting unit may determine that the quality of the communication channel is maintained in a normal state when the channel quality degradation parameter is smaller than the threshold value.

Also, the quality predicting unit may perform the quality degradation countermeasure process when it is determined that the quality of the communication channel is drastically degraded, and the corresponding process may include adjusting the connection beam or performing a beam searching and tracking process on the candidate beam Setting the time to maintain the current state for the RLF recovery decision or handover decision after the occurrence of a problem in the RLF recovery or handover procedure to be shorter than a preset time, User channel configuration, and system configuration.

According to an embodiment of the present invention, in a communication environment in which a high-speed communication service is provided to a user, a channel environment of a user is tracked, and a rapid communication quality deterioration is predicted in advance, It is possible to prevent a communication quality degradation and a communication failure of the user due to the environmental deterioration.

In addition, when it is determined that the degree of the sudden drop in the communication quality is predicted to be a certain level or less, and it is determined that there is a problem in providing a stable communication quality to the user and a problem in communication channel maintenance, The quality of the communication service can be improved by providing a more reliable and stable communication service.

1 is a diagram illustrating a received signal measurement state in a communication environment according to an embodiment of the present invention.
2 is a flowchart of a communication quality prediction method according to an embodiment of the present invention.
3 is a diagram illustrating a structure of a communication quality prediction apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

In this specification, a terminal includes a terrestrial station, a return channel satellite terminal (RCST), a mobile station (MS), a mobile terminal (MT), a subscriber station (SS), a portable subscriber station Station, a PSS, a user equipment (UE), an access terminal (AT), and the like, and may include all or part of an earth station, RCST, mobile terminal, subscriber station, mobile subscriber station, May include the functions of

In this specification, a central station includes a base station (BS), an access point (AP), a radio access station (RAS), a node B, a base transceiver station (BTS) Mobile Multihop Relay (MMR) -BS, or the like, and may include all or some functions of an access point, a radio access station, a Node B, a base transceiver station, and an MMR-BS.

Hereinafter, a communication quality predicting method and apparatus according to an embodiment of the present invention will be described with reference to the drawings.

In the embodiment of the present invention, when a high-speed communication service utilizing a relatively high frequency band is provided, a user accesses a base station in a stable communication environment to receive a high-speed communication service, It is assumed that the environment remains constant. Here, the communication quality for the user is measured based on the strength of the received signal (for example, Reference Signal Received Power (RSRP) or Received Signal Strength Indicator (RSSI)), but is not limited thereto.

The received signal can be estimated by the channel characteristics model, and the relationship between the distance between the transmitting end that transmits the signal and the receiving end that receives the signal and the received signal is as follows.

는 측정에 관련된 기준 거리를 나타내며,

는 신호를 수신하는 지점(또는 수신단)과 전송점(또는 송신단) 사이의 거리를 나타낸다.

는 기준 거리에서 해당 주파수의 전송 특성을 반영하는 값으로 상수 값을 갖는다. 그리고

는 채널 모델의 특성을 결정짓는 감쇄 상수이다.Where P _tx represents the intensity of the transmitted signal and P _rx represents the intensity of the received signal. The intensity of each signal may be a measured value or a value calculated through an average filter or a predictive filter.

Represents a reference distance related to the measurement,

Represents a distance between a point (or a receiving end) at which a signal is received and a transmission point (or a transmitting end).

Is a value that reflects the transmission characteristics of the frequency at the reference distance and has a constant value. And

Is an attenuation constant that determines the characteristics of the channel model.

The UE can perform the measurement on the received signal according to the measurement period value set by the base station.

1 is a diagram illustrating a received signal measurement state in a communication environment according to an embodiment of the present invention.

)의 값을 d₁, d₂, d₃ 라고 할 때, 측정 시간에 대한 이동 거리의 변화는 다음과 같이 나타낼 수 있다. If a terminal located a certain distance d from the base station measures the received signal at regular intervals, the relative change value of the measured position may be close to zero corresponding to the stop state if the measurement period is relatively short, It can be seen that it has a constant variation value with no significant change. That is, the ratio of the reference distance and the current position of the terminal to the measurement times t ₁ , t ₂ , t ₃ having a constant measurement period

) Is d ₁ , d ₂ , and d ₃ , the change in the travel distance with respect to the measurement time can be expressed as follows.

가 0의 값을 가지는 경우에는 고정 상태(stationary state)를 나타내며,

가 특정 상수의 값을 가지는 경우에는 정상 상태(steady state)를 나타낸다. d_n-1은 단말의 이전 위치를 나타내며, d_n은 단말의 현재 위치를 나타낸다. here,

Represents a stationary state when the value is 0,

(Steady state) when it has a certain constant value. d _n-1 represents the previous position of the UE, and d _n represents the current position of the UE.

Assuming that the distance traveled by the terminal during the measurement period is relatively small in comparison with the distance between the terminal and the base station in a super high-speed communication system utilizing the very high frequency band, the change in the travel distance of the terminal according to Equation (2) Can be expressed by Equation (3).

Thus, when the distance traveled by the terminal during the measurement period is relatively small compared to the distance between the terminal and the base station, the change in the travel distance with respect to the measurement time is measured to be very small. That is, the change of the mobility of the terminal according to the measurement period is very small, and the ratio of distances between the terminal and the base station for each measurement time is similar.

The relationship between the distance and the received signal according to Equation (1) above can be summarized as follows.

은 위의 수학식과 같은 방식으로 수신 신호의 정보를 기반으로 추산된 정보이다. here,

Is the information estimated based on the information of the received signal in the same manner as the above equation.

On the other hand, assuming that a communication channel state of a user of a high-speed communication service utilizing a high frequency band is in a steady state, the user channel characteristic can be explained by the same channel characteristic. Therefore, it can be seen that the channel attenuation constants of the measurement periods t ₁ , t ₂ , and t ₃ have constant values. However, when the quality of the user channel deteriorates drastically and t ₁ and t ₂ reach the t ₃ state and the channel state is different from the previous _one , t ₁ and t ₂ , the channel attenuation constant value is "α" , The channel attenuation constant of t ₃ becomes "k x alpha ", where k has a larger positive value.

If k is derived from the above assumption, the k value can be expressed as follows.

Therefore, if the value of k increases by more than a predetermined threshold value, the channel environment of the user is rapidly deteriorated. Based on this, it is possible to cope with the degradation of the user communication service environment.

In the embodiment of the present invention, it is determined that a sudden channel state drop (Rapid Ch.Degradation) occurs when the value of k is compared with a predetermined threshold (Degradation threshold) do.

As described above, if the channel state of the user is changed in a steady state and a sudden quality degradation occurs, k has a value larger than 1. Therefore, if the user's channel is predicted to experience a rapid deterioration in quality through Equation (6) or if it is predicted that the connection state of the active beam in the beamforming is rapidly deteriorated, the quality degradation countermeasure process can be performed quickly. Specifically, in the case of beamforming, the connection beam is adjusted or the beam searching and tracking process for the candidate beam is performed in an early stage. Or if a quality degradation is predicted in a channel recovery procedure such as an RLF recovery or a handover procedure, by setting a shorter time to maintain observation of the current state for RLF recovery decision or handover decision after a problem occurs, Identify and respond. In addition, the predicted channel environment change information is reflected in the user channel configuration and the system setting, so that it can be utilized for providing more reliable and stable communication service to the users in the same environment.

2 is a flowchart of a communication quality prediction method according to an embodiment of the present invention.

In an embodiment of the present invention, in an environment providing a terminal with a high-speed communication service utilizing a high-frequency band, the communication quality prediction apparatus measures the strength of a received signal (S100). The communication quality predicting device measures the strength of the received signal by a preset measurement period. Here, the change of the mobility of the terminal according to the measurement period is very small, and the ratios of the distances between the terminal and the base station for each measurement time of the measurement period are similar.

When the communication channel state of the terminal is in a normal state, the channel attenuation constant for the measurement time has a constant value, and the k value, that is, the channel quality degradation variable is calculated in consideration of the fact that the channel attenuation constant value, (S110).

의 조건에 따라 산출될 수 있으며, 여기서,

는

을 만족하는 값이다.

는 신호를 수신하는 지점(또는 수신단)과 전송점(또는 송신단) 사이의 거리를 나타내고, 또

는 기준 거리를 나타낸다 The channel quality degradation variable k

, Where < RTI ID = 0.0 >

The

.

Represents a distance between a point (or a receiving end) at which a signal is received and a transmission point (or a transmitting end), and

Represents the reference distance

Here, the reference distance represents the distance between the terminal and the base station set for measuring the received signal. It is assumed that the strength of the transmission signal to the terminal is already known.

The communication quality prediction device compares the calculated channel quality degradation variable k with a preset threshold (S120). If the calculated channel quality degradation variable k is smaller than the threshold value, it is determined that the channel state of the user is maintained in a normal state (S130).

On the other hand, if the calculated channel quality degradation variable k is greater than or equal to the threshold value, it is determined that the channel state of the user is degraded in a normal state and a rapid quality degradation occurs (S140). In the case where the communication quality prediction device predicts a state in which a rapid quality deterioration can occur, the quality degradation countermeasure process is performed. As described above, the quality degradation countermeasure process is performed by adjusting the connection beam or performing the beam searching and tracking process for the candidate beam in an early stage, or after a problem occurs in a channel recovery procedure such as RLF recovery or handover procedure, Setting a shorter time for maintaining the current state observation for a recovery decision or a handover decision, reflecting the predicted channel environment change information to the user channel configuration and the system setting, But is not limited thereto.

3 is a diagram illustrating a structure of a communication quality prediction apparatus according to an embodiment of the present invention.

3, the communication quality prediction apparatus 100 includes a processor 110, a memory 120, and a radio frequency (RF) converter 130. As shown in FIG. The processor 110 may be configured to implement the methods described above based on Figs.

For this, the processor 110 may include a received signal measurement unit 111, a channel quality degradation variable calculation unit 112, and a quality prediction unit 113.

The received signal measuring unit 111 measures the intensity of the received signal according to a preset measurement period.

The channel quality degradation parameter calculator 112 calculates a channel quality degradation parameter based on a constant value that reflects the transmission characteristics of the corresponding frequency in the strength of the transmission signal, the strength of the received signal, and the reference distance.

The quality predicting unit 113 compares the calculated channel quality degradation variable k with a preset threshold value. If the channel quality degradation variable k is smaller than the threshold value, it is determined that the channel state of the user is maintained in the normal state. On the other hand, if the calculated channel quality degradation variable k is greater than or equal to the threshold value, the channel state of the user is degraded in a steady state to predict a state in which rapid quality degradation can occur.

The memory 120 is coupled to the processor 110 and stores various information related to the operation of the processor 110. [ The RF converter 130 is connected to the processor 110 and transmits or receives radio signals.

The embodiments of the present invention are not limited to the above-described apparatuses and / or methods, but may be implemented through a program for realizing functions corresponding to the configuration of the embodiment of the present invention, a recording medium on which the program is recorded And such an embodiment can be easily implemented by those skilled in the art from the description of the embodiments described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (9)

In a method for predicting a communication channel quality in an environment providing a high-speed communication service utilizing a high-frequency band to a terminal,
Measuring the strength of the received signal every predetermined measurement period;
Calculating a channel quality deterioration parameter for a communication channel between the terminal and the base station based on the strength of the received signal;
Comparing the channel quality degradation variable with a preset threshold; And
Determining that the quality of the communication channel is drastically degraded if the channel quality degradation parameter is greater than or equal to the threshold;
/ RTI > The method of claim 1, wherein
The channel quality degradation variable k is

, Where < RTI ID = 0.0 >

The

, ≪ / RTI >

Represents a distance between a point (or a receiving end) at which a signal is received and a transmission point (or a transmitting end)

≪ / RTI > The method of claim 1, wherein
Determining that the quality of the communication channel is maintained in a normal state when the channel quality degradation variable is smaller than the threshold value
≪ / RTI > The method of claim 1, wherein
When it is determined that the quality of the communication channel is drastically degraded, performing quality degradation countermeasure processing
≪ / RTI > The method of claim 4, wherein
The corresponding processing may include adjusting the connection beam or performing the beam searching and tracking process for the candidate beam early, RLF (radio link failure) recovery, or RLF recovery after a problem occurs in a handover procedure or handover decision Setting the time to maintain the current state to be shorter than a predetermined time, and reflecting the predicted channel environment change information to the user channel configuration and the system setting. In an apparatus for predicting a communication channel quality in an environment providing a terminal with a high-speed communication service utilizing a high-frequency band,
A radio frequency converter for transmitting and receiving signals through an antenna, and
And a process coupled to the radio frequency translator to predict the communication channel quality,
The processor comprising:
A received signal measuring unit for measuring an intensity of a received signal at every preset measurement period through the RF transceiver;
A channel quality degradation variable calculation unit for calculating a channel quality degradation parameter for a communication channel between the UE and the base station based on the strength of the received signal;
Comparing the channel quality degradation parameter with a preset threshold value and determining that the quality of the communication channel is drastically degraded if the channel quality degradation parameter is greater than or equal to the threshold value,
Lt; / RTI > The method according to claim 6,
The channel quality degradation variable k is

, Where < RTI ID = 0.0 >

The

, ≪ / RTI >

Represents a distance between a point (or a receiving end) at which a signal is received and a transmission point (or a transmitting end)

Represents a reference distance. The method of claim 6, wherein
Wherein the quality predicting unit determines that the quality of the communication channel is maintained in a steady state when the channel quality degradation variable is smaller than the threshold value. The method of claim 6, wherein
Wherein the quality predicting unit performs quality degradation countermeasure processing when it is determined that the quality of the communication channel is drastically degraded,
The corresponding processing may include adjusting the connection beam or performing the beam searching and tracking process for the candidate beam early, RLF (radio link failure) recovery, or RLF recovery after a problem occurs in a handover procedure or handover decision Setting the time for maintaining the current state to be shorter than a predetermined time, and reflecting the predicted channel environment change information to the user channel configuration and the system setting.

Images