KR101001662B1 - Method for decoding received signal in wireless network system - Google Patents

Abstract

The present invention relates to a method for decoding a received signal in a wireless network environment. As the interference signal included in a received signal can be decoded in a wireless network environment, the decoding complexity is reduced by removing and decoding the corresponding interference signal from the received signal. To provide a method for decoding a received signal in a wireless network environment to more efficiently and decode the received signal.

To this end, the present invention provides a method for decoding a received signal, the method comprising: extracting a corresponding channel value and MCS (Modulation and Coding Scheme) information from the received signal from the main transmitter and the interference signal received from another transmitter; Calculating a first signal-to-interference noise ratio at the corresponding destination receiver using the extracted channel value and MCS information of the interference signal; Calculating a second signal-to-interference noise ratio using the strength of the received interference signal; And decoding the received signal after decoding the interference signal as the calculated second signal to interference noise ratio exceeds the calculated first signal to interference noise ratio.

Wireless network, interference cancellation, channel value, modulation and coding scheme (MCS), signal strength, decoding

Description

Received signal decoding method in wireless network environment {METHOD FOR DECODING RECEIVED SIGNAL IN WIRELESS NETWORK SYSTEM}

The present invention relates to a method of decoding a received signal in a wireless network environment, and more particularly, by decoding the interference signal from the received signal according to the decoding of the interference signal included in the received signal in a wireless network environment, The present invention relates to a method for decoding a received signal in a wireless network environment to reduce decoding complexity and more efficiently decode a received signal.

In general, a wireless network system includes a transmitter (TX) for controlling transmission power and a receiver (RX) having a sequential interference cancellation (SIC) function.

Here, the base station includes an outdoor base station installed outdoors, an indoor base station separately installed indoors, and an indoor base station group installed in a group indoors.

In addition, indoor base stations installed separately include indoor indoor base stations used in homes, and indoor base stations installed in groups include a group of indoor indoor base stations that can be used in an enterprise.

In addition, the sequential interference cancellation method refers to a technique of sequentially removing interference signals from a received signal after decoding an interference signal in a receiver when signals transmitted from a plurality of transmitters are simultaneously received.

In the conventional method of decoding a received signal, when a receiver simultaneously receives several signals, all of the interference signals are processed as noise to decode a desired signal. For example, when there are K pairs of transmitters and receivers, the received signal at the i th receiver is expressed by Equation 1 below.

Where h _{k and i} are channel characteristics between the k th transmitter and the i th receiver, x _k is a transmission signal of power P _k that the k th transmitter wants to send to the k th receiver, and n _i is the noise received by the i th receiver Each means. In this case, n _i follows a normal distribution having an average of 0 and a variance N.

는 간섭신호를 의미한다.Also,

Denotes an interference signal.

Therefore, the signal-to-interference noise ratio (SINR) that the i-th transmitter sends to the i-th receiver may be expressed as Equation 2 below.

The conventional method of decoding a received signal decodes the received signal represented by Equation 1 as noise without removing the interference signal, thereby increasing complexity due to unnecessary decoding process and increasing the overall processing capacity. There is a problem to reduce.

It is a problem of the present invention to solve the problems of the prior art as described above.

Accordingly, the present invention can decode the interference signal included in the received signal in a wireless network environment, and then remove the corresponding interference signal from the received signal and then decode it, thereby reducing the decoding complexity and more efficiently decoding the received signal. It is an object of the present invention to provide a decoding method of a received signal in a network environment.

In addition, the present invention determines whether the interference signal included in the received signal can be decoded in a wireless network environment, and if possible, removes the interference signal from the received signal and then decodes it. It is another object of the present invention to provide a method for decoding a received signal in a wireless network environment to reduce a decoding complexity and to efficiently decode a received signal by decoding a received signal from which an interference signal has been removed after performing the method.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

In accordance with another aspect of the present invention, there is provided a method of decoding a received signal, the method comprising: extracting a channel value and MCS (Modulation and Coding Scheme) information from a received signal from a main transmitter and an interference signal received from another transmitter; ; Calculating a first signal-to-interference noise ratio at the corresponding destination receiver using the extracted channel value and MCS information of the interference signal; Calculating a second signal-to-interference noise ratio using the strength of the received interference signal; And decoding the received signal after decoding the interference signal as the calculated second signal to interference noise ratio exceeds the calculated first signal to interference noise ratio.

In addition, the method of the present invention for achieving the above another object, in the received signal decoding method, the channel value and MCS (Modulation and Coding Scheme) information from the received signal from the main transmitter and the interference signal received from the other transmitter Extracting; Calculating a first signal-to-interference noise ratio at the corresponding destination receiver using the extracted channel value and MCS information of the interference signal; Calculating a second signal-to-interference noise ratio using the strength of the received interference signal; Checking whether the interference signal decoding capability of the calculated second signal-to-interference noise ratio exceeds the calculated first signal-to-interference noise ratio; Decoding the received signal after removing the interference signal if exceeded; And a decoding step of reducing and transmitting the transmission power of the main transmitter in the equation for calculating the second signal-to-interference noise ratio if it does not exceed.

In addition, the present invention solves an inefficient use of resources due to interference generated during transmission and reception by using an interference cancellation (SIC) function and a transmission power control function.

According to the present invention as described above, since the interference signal included in the received signal can be decoded in a wireless network environment, the interference signal can be decoded and then decoded to reduce the decoding complexity and more efficiently decode the received signal. It can be effective.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, It can be easily carried out. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, when a receiver receives signals from a plurality of transmitters, a transmitter that sends a message to the receiver as a destination is called a main transmitter. In this case, it is assumed that the main transmitter uses the maximum transmission power, and the influence on other transmitters is minimal.

1 is an exemplary view of a wireless network environment to which the present invention is applied.

As shown in FIG. 1, the wireless network environment to which the present invention is applied may include a first terminal MS ₁ 11, a second terminal MS ₂ 12, and a first base station BS ₁ 21. , And a second base station (BS ₂ ) 22.

At this time, in a situation where the first base station 21 has already formed a cell to support the first terminal 11, the second base station 22 forms another small cell in the cell to support the second terminal 12. Doing.

In addition, it is assumed that the signal of the first base station 21 acts as an interference to the second terminal 12, but the signal of the second base station 22 has little effect on the first terminal 11.

In addition, the first base station 21 and the second base station 22 transmit at a predetermined transmission power.

In addition, the case where the first base station 21 and the second base station 22 operates as a transmitter, and the first terminal 11 and the second terminal 12 operates as a receiver will be described.

In addition, the first base station 21 and the second base station 22 may arbitrarily adjust the transmission power within the maximum transmission power, the first terminal 11 and the second terminal 12 has an interference cancellation (SIC) function Have.

2 is a flowchart illustrating a method of decoding a received signal in a wireless network environment according to the present invention.

First, channel values and MCS (Modulation and Coding Scheme) information are extracted from a received signal from a main transmitter and an interference signal received from another transmitter (201).

Thereafter, a first signal-to-interference noise ratio is calculated at the destination receiver using the extracted channel value and MCS information of the interference signal (202).

Thereafter, a second signal to interference noise ratio is calculated using the received interference signal strength (203).

Thereafter, as the calculated second signal-to-interference noise ratio exceeds the calculated first signal-to-interference noise ratio, the interference signal is decoded and removed, and then the received signal is decoded (204).

Here, if the second signal-to-interference noise ratio does not exceed the first signal-to-interference noise ratio, the interference signal is regarded as noise and decoded in a conventional manner.

This decoding method will be described in more detail with reference to FIG. 1.

First, the first terminal 11 stores the channel value and the MCS value through the first received signal received from the first base station 21.

In addition, the second terminal 12 stores the channel value and the MCS value through the second received signal received from the second base station 22. In this case, the second received signal includes an interference signal (first received signal) from the first base station 21, and knows the channel value and the MCS value with the first base station 21 through the interference signal.

Thereafter, the second terminal 12 calculates a signal-to-interference noise ratio (hereinafter, referred to as a first signal-to-interference noise ratio) of the first received signal using the channel value and the MCS information with the first base station 21.

Subsequently, the signal-to-interference noise ratio (hereinafter referred to as the second signal-to-interference noise ratio) of the interference signal is calculated by using the strength of the interference signal received by the second terminal 12 to the first base station 21.

As the calculated second signal to interference noise ratio exceeds the first signal to interference noise ratio, the interference signal is decoded and then removed from the second received signal.

Thereafter, the second received signal from which the interference signal has been removed is decoded.

3 is a flowchart illustrating another embodiment of a method for decoding a received signal in a wireless network environment according to the present invention.

First, channel values and MCS (Modulation and Coding Scheme) information are extracted from a received signal from a main transmitter and an interference signal received from another transmitter (301).

Thereafter, a first signal-to-interference noise ratio is calculated at the destination receiver using the extracted channel value and MCS information of the interference signal (302).

Then, the second signal-to-interference noise ratio is calculated using the strength of the interference signal received from the other transmitter (303).

Then, it is checked whether the calculated second signal to interference noise ratio exceeds the first signal to interference noise ratio (304). That is, it is determined whether the interference signal can be decoded.

As a result of the check 304, if the second signal-to-interference noise ratio exceeds the first signal-to-interference noise ratio, the received signal is decoded and then decoded (305). In this case, when there are a plurality of decoded interference signals, only the interference signal having the greatest strength may be removed or all of the interference signals may be sequentially removed according to the signal strength.

As a result of the check 304, if the second signal-to-interference noise ratio does not exceed the first signal-to-interference noise ratio, the transmission power of the main transmitter is determined in the equation for calculating the second signal-to-interference noise ratio (for example, Equation 6 below). Reduce (306). At this time, the transmission power of the main transmitter means P _i -ΔP in Equation 6 below.

Thereafter, the transmission power of the main transmitter is greater than zero (307). If it exceeds, the process proceeds to the "304" process. If not, the interference signal is regarded as noise and decoded (308).

In addition, when the transmission power is lowered and the process "304" is satisfied, it is determined whether the first transmission amount exceeds the second transmission amount, and if it does not exceed, the process "305" is performed. Perform the process. Here, the first transmission amount and the second transmission amount will be described in detail below.

Hereinafter, a process of decoding a received signal in a wireless network environment will be described in more detail.

First, the receiver performs an initialization process as follows to obtain channel values and MCS (Modulation and Coding Scheme) information of a received signal and an interference signal.

That is, the channel value is estimated from the received signal from the main transmitter and the interference signal received from the other transmitter. At this time, the received signal strength from the main transmitter and the interference signal strength from the other transmitter are selected signals exceeding the threshold.

Thereafter, MCS information is extracted by decoding a map included in the received signal and the interference signal using the estimated channel value. Here, a map generally refers to a portion of a transmitted signal that contains MCS information that the transmitter uses to send a message to the receiver.

Initialization is completed through this process, and the channel value and MCS information thus obtained are used to calculate a Signal to Interference Noise Ratio (SINR).

On the other hand, the process of calculating the first transmission amount by recognizing the interference signal as a noise in the received signal using Equation 3 below.

Here, C (x) includes all functions representing link capacity when SINR is x, and a unit is bit / sec / Hz. At this time, SINR _{i, i} is the same as [Equation 2].

Also, the second signal-to-interference noise ratio calculated using the strength of the interference signal received from another transmitter must exceed the first signal-to-interference noise ratio calculated using the channel value and MCS information of the interference signal received from the other transmitter. The interference signal can be decoded. Such an interference signal must be decoded to be removed.

This is performed using Equation 4 below.

Here, SINR _{j , j} indicates a case where the j-th receiver receives the transmission signal of the j-th transmitter _, and SINR _{j , i} indicates a case where the i-th receiver receives the transmission signal of the j-th transmitter.

Then, when the second signal-to-interference noise ratio exceeds the first signal-to-interference noise ratio, the interference signal received from another transmitter is decoded and then removed. In this case, when there are a large number of interference signals from other transmitters that can be decoded, only the received signal having the greatest intensity may be removed or all of the signals may be sequentially removed according to the signal strength.

Herein, the description of the decoding itself is not the subject matter to be dealt with in the present invention, and if necessary, a publicly known publicly known technique may be used.

For example, the SINR _{i , i} of the signal obtained from the i-th transmitter by removing the interference signal from the j-th transmitter from the j-th transmitter from the received signal is expressed by Equation 5 below.

Here, the second transmission amount may be calculated by applying Equation 5 to Equation 3.

On the other hand, if the second signal-to-interference noise ratio does not exceed the first signal-to-interference noise ratio, the transmission power (P _i ) of the main transmitter is reduced (ΔP) in Equation 6, which represents the second signal-to-interference noise ratio.

At this time, the transmission power of the main transmitter is controlled so that the transmission power is not 0 or less. If the transmission signal is 0 or less, the interference signal is regarded as noise if the second signal to interference noise ratio does not exceed the first signal to interference noise ratio. Decrypt

Here, in order to remove the interference signal from the j-th transmitter, SINR _{j , i} that the i-th receiver can obtain after the transmit power of the i-th transmitter is reduced by ΔP is expressed by Equation 6 below.

4 is a diagram illustrating a performance analysis of a method of decoding a received signal in a wireless network environment according to the present invention.

First, assuming that the distance between the first base station 21 and the second terminal 12 and the distance between the second base station 22 and the second terminal 12 are constant, the first base station 21 and the first base station 21 are the same. The distance between the terminals 11 is changed, and the transmission rate relationship of the second terminal 12 has been described.

That is, the strength of the signal transmitted from the first base station 21 to the second terminal 12 is fixed to 15 dB, and the strength of the signal transmitted from the second base station 22 to the second terminal 12 is fixed to 20 dB. Then, the signal-to-interference noise ratio of the first base station 21 and the first terminal 11 was changed from 0 dB to 30 dB.

In this case, the channel and noise are complex random variables following a normal distribution, the average is all zero, the channel variance is N, and the variance of noise is set to one.

As shown in FIG. 4, in the situation where the signal-to-interference noise ratio between the first base station 21 and the first terminal 11 is 0 dB to 30 dB, the transmission amount from the second base station 22 to the second terminal 12 is conventionally determined. Method, proposed receiving method, proposed transmitting and receiving method.

Here, the conventional method means a method of considering the interference signal as noise, the proposed reception method means a method of removing the interference signal, the proposed transmission and reception method is to remove the interference signal and to adjust the transmission power of the main transmitter It means the way all the process is done.

Through this, it can be seen that the proposed transmission / reception scheme shows a higher transmission amount than the conventional scheme and the proposed reception scheme in a section in which the signal-to-interference noise ratio of the first base station 21 to the first terminal 11 is not relatively large.

That is, when the SNR of BS ₁ -MS ₁ is 0dB, the transmission amount of the proposed reception scheme is increased by 50% compared to the transmission rate of the conventional scheme, and the transmission amount of the proposed transmission / reception scheme is 95% compared to the transmission ratio of the conventional scheme. It can be seen that increased.

On the other hand, the method of the present invention as described above can be written in a computer program. And the code and code segments constituting the program can be easily inferred by a computer programmer in the art. In addition, the written program is stored in a computer-readable recording medium (information storage medium), and read and executed by a computer to implement the method of the present invention. The recording medium may include any type of computer readable recording medium.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention can be used for decoding received signals.

1 is an exemplary view of a wireless network environment to which the present invention is applied;

2 is a flowchart illustrating a method of decoding a received signal in a wireless network environment according to the present invention;

3 is a flowchart illustrating another embodiment of a method for decoding a received signal in a wireless network environment according to the present invention;

4 is a diagram illustrating a performance analysis of a method of decoding a received signal in a wireless network environment according to the present invention.

* Explanation of symbols for the main parts of the drawings

11: first terminal 12: second terminal

21: first base station 22: second base station

Claims (5)

In the received signal decoding method, Extracting a corresponding channel value and MCS (Modulation and Coding Scheme) information from a received signal from a main transmitter and an interference signal received from another transmitter; Calculating a first signal-to-interference noise ratio at the corresponding destination receiver using the extracted channel value and MCS information of the interference signal; Calculating a second signal-to-interference noise ratio using the strength of the received interference signal; And A decoding step of decoding the received signal after decoding the interference signal as the calculated second signal to interference noise ratio exceeds the calculated first signal to interference noise ratio; Received signal decoding method comprising a. The method of claim 1, The decoding step, If the interference signal is a plurality, the received signal decoding method for decoding after removing the interference signal having the largest signal strength. delete In the received signal decoding method, Extracting a corresponding channel value and MCS (Modulation and Coding Scheme) information from a received signal from a main transmitter and an interference signal received from another transmitter; Calculating a first signal-to-interference noise ratio at the corresponding destination receiver using the extracted channel value and MCS information of the interference signal; Calculating a second signal-to-interference noise ratio using the strength of the received interference signal; Checking whether the interference signal decoding capability of the calculated second signal-to-interference noise ratio exceeds the calculated first signal-to-interference noise ratio; Decoding the received signal after removing the interference signal if exceeded; And Decoding step of decoding after reducing the transmission power of the main transmitter in the equation for calculating the second signal-to-interference noise ratio, if not exceeded as a result of the confirmation Received signal decoding method comprising a. The method of claim 4, wherein The decoding step, Reconfirming whether or not decoding is possible after reducing the transmission power of the main transmitter in the second signal to interference noise ratio; Decoding the received signal after removing the interference signal if decoding is possible as a result of the reconfirmation; And If it is impossible to decode within the control range of the transmission power as a result of the reconfirmation, deciphering the interference signal as noise Received signal decoding method comprising a.

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