KR102602449B1 - Apparatus, method, computer-readable storage medium and computer program for successive interference cancellation using re-generating signal in non-orthogonal multiple access system of uplink satellite communication - Google Patents

Abstract

An interference removal device according to an embodiment includes a first receiver that receives an overlapped signal including a strong signal and a weak signal in a non-orthogonal multiple access system, demodulates and decodes the overlapped signal, and extracts a strong signal bit; a channel estimation unit that receives a synchronization signal corresponding to the strong signal and determines a channel estimate value of the strong signal; a signal regeneration unit that generates a regenerated strong signal using the strong signal bit and the channel estimate value; And it may include a discriminator that performs serial interference cancellation by generating a discrimination signal consisting of the sum or difference of the offset correction overlap signal and the regeneration strong signal based on the power difference value of the offset correction overlap signal and the regeneration strong signal.

Description

Interference cancellation apparatus, method, computer-readable recording medium and computer program using signal regeneration in a non-orthogonal multiple access system of uplink satellite communication SIGNAL IN NON-ORTHOGONAL MULTIPLE ACCESS SYSTEM OF UPLINK SATELLITE COMMUNICATION}

The present invention relates to an interference cancellation apparatus and method using signal regeneration in a non-orthogonal multiple access system of uplink satellite communication, a computer-readable recording medium, and a computer program.

The Non-Orthogonal Multiple Access (NOMA) system is a method of transmitting two different, non-orthogonal signals by overlapping them. Non-orthogonal multiple access methods can be divided into a method that distinguishes signals through a power domain and a method that distinguishes signals through a code domain.

Meanwhile, in the case of uplink low-orbit satellite communication, a Doppler rate of up to 580 Hz/s occurs depending on altitude. In order to demodulate a non-orthogonal multiple access signal, serial interference cancellation (SIC) must be performed at the receiving end. However, there is a problem in that the Doppler rate is a major obstacle in performing serial interference cancellation in a low-orbit satellite communication environment. .

Republic of Korea Patent Publication No. 10-2074217: Adaptive rate division method and system for uplink non-orthogonal multiple access system

The problem to be solved by the present invention is to propose a technology to effectively perform serial interference cancellation (SIC) using signal regeneration in a non-orthogonal multiple access (NOMA) system of uplink satellite communication. It is done.

However, the problem to be solved by the present invention is not limited to the above-mentioned, and includes purposes that are not mentioned but can be clearly understood by those skilled in the art from the description below. can do.

An interference removal device according to an embodiment of the present invention receives an overlapping signal including a strong signal and a weak signal in a non-orthogonal multiple access (NOMA) system, demodulates and decodes the overlapping signal, and generates a strong signal bit. a first receiver that extracts; a channel estimation unit that receives a synchronization signal corresponding to the strong signal and determines a channel estimate value of the strong signal; a signal regeneration unit that generates a regenerated strong signal using the strong signal bit and the channel estimate value; and a discriminator that performs serial interference cancellation (SIC) by generating a discrimination signal consisting of the sum or difference of the offset correction overlap signal and the regeneration strong signal based on the power difference value between the offset correction overlap signal and the regeneration strong signal. It can be included.

In addition, the channel estimation unit includes an automatic gain control unit that maintains the size of the synchronization signal corresponding to the strong signal within a certain range; a square root raised cosine filter unit that samples the signal output from the automatic gain control unit; a frequency offset correction unit that performs frequency offset correction on the signal output from the square root raised cosine filter unit; a timing offset correction unit that corrects timing offset for the signal output from the frequency offset correction unit; and a channel estimation unit that determines the channel estimate value for estimating a channel used for the strong signal based on the signal output by the timing offset correction unit.

Additionally, the frequency offset correction unit may determine the frequency offset value used for the strong signal based on the synchronization signal.

Additionally, the first receiver may perform frequency correction of the overlapping signal based on the frequency offset value to generate the offset corrected overlapping signal and transmit it to the determination unit.

Additionally, the signal regeneration unit may include a channel coding unit that encodes the strong signal bits; a modulator that modulates the encoded strong signal bits; A square root raised cosine filter unit that samples the modulated signal; and a channel filter unit that generates the regenerated strong signal using the sampled signal and the channel estimate value.

In addition, the determination unit may include a subtraction unit generating a first signal by subtracting the regenerative strong signal from the offset correction superimposed signal; a summation unit that generates a second signal by summing the regenerated strong signal from the offset correction superimposed signal; a power measuring unit that measures the power of the first signal; and outputting the first signal as the determination signal if the power level of the first signal is less than or equal to a predetermined threshold, and outputting the second signal as the determination signal if the power level of the first signal is greater than a predetermined threshold. It may include a switch unit that outputs a signal.

Additionally, the device may further include a second receiver that demodulates and decodes the discrimination signal to extract a weak signal bit.

The interference cancellation method performed by the interference removal device according to an embodiment of the present invention is to receive an overlapping signal including a strong signal and a weak signal in a non-orthogonal multiple access (NOMA) system, and Demodulating and decoding to extract strong signal bits; Receiving a synchronization signal corresponding to the strong signal and determining a channel estimate value of the strong signal; generating a regenerative strong signal using the strong signal bit and the channel estimate value; And performing serial interference cancellation (SIC) by generating a discrimination signal consisting of the sum or difference of the offset correction overlap signal and the regeneration strong signal based on the power difference value between the offset correction overlap signal and the regeneration strong signal. It can be included.

In addition, the step of determining the channel estimate value includes maintaining the size of the synchronization signal corresponding to the strong signal within a certain range and outputting it; sampling the output signal; performing frequency offset correction on the output signal;

correcting timing offset for the output signal; and determining the channel estimate value for estimating a channel used for the strong signal based on the output signal.

Additionally, determining the channel estimate value may further include determining a frequency offset value used for the strong signal based on the synchronization signal.

Additionally, the step of extracting the strong signal bit may include generating the offset-corrected overlap signal by performing frequency correction of the overlap signal based on the frequency offset value.

Additionally, generating the regenerative strong signal may include encoding the strong signal bits; Modulating the encoded strong signal bits; sampling the modulated signal; and generating the regenerated strong signal using the sampled signal and the channel estimate value.

In addition, performing the serial interference cancellation may include generating a first signal by subtracting the regenerative strong signal from the offset correction superimposed signal; generating a second signal by adding the regenerated strong signal to the offset correction superimposed signal; measuring the power of the first signal; and outputting the first signal as the determination signal if the power level of the first signal is less than or equal to a predetermined threshold, and outputting the second signal as the determination signal if the power level of the first signal is greater than a predetermined threshold. It may include the step of outputting a signal.

Additionally, the method may further include the step of demodulating and decoding the discrimination signal to extract a weak signal bit.

A computer-readable recording medium storing a computer program according to an embodiment of the present invention, which receives an overlapping signal including a strong signal and a weak signal in a Non-Orthogonal Multiple Access (NOMA) system, Extracting strong signal bits by demodulating and decoding the overlapping signals; Receiving a synchronization signal corresponding to the strong signal and determining a channel estimate value of the strong signal; generating a regenerative strong signal using the strong signal bit and the channel estimate value; And performing serial interference cancellation (SIC) by generating a discrimination signal consisting of the sum or difference of the offset correction overlap signal and the regeneration strong signal based on the power difference value between the offset correction overlap signal and the regeneration strong signal. It can be included.

A computer program stored in a computer-readable recording medium according to an embodiment of the present invention, which receives an overlapping signal including a strong signal and a weak signal in a Non-Orthogonal Multiple Access (NOMA) system, Extracting strong signal bits by demodulating and decoding the overlapping signals; Receiving a synchronization signal corresponding to the strong signal and determining a channel estimate value of the strong signal; generating a regenerative strong signal using the strong signal bit and the channel estimate value; And performing serial interference cancellation (SIC) by generating a discrimination signal consisting of the sum or difference of the offset correction overlap signal and the regeneration strong signal based on the power difference value between the offset correction overlap signal and the regeneration strong signal. It can be included.

Embodiments of the present invention are excellent in low-orbit satellite communication where the Doppler effect is large, and when operating a power domain-based Non-Orthogonal Multiple Access (NOMA) system, serial interference is removed even in the section where the intensity difference between the two signals is low ( Since Successive Interference Cancellation (SIC) can be performed, the strength difference between the two signals can be effectively operated in a wide range when using the uplink.

The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description below. will be.

Figure 1 is a configuration diagram of a non-orthogonal multiple access system for uplink satellite communication according to an embodiment of the present invention.
Figure 2 is a configuration diagram of an interference removal device using signal regeneration according to an embodiment of the present invention.
Figure 3 is an exemplary diagram of an interference removal device using signal regeneration according to an embodiment of the present invention.
Figure 4 is an exemplary diagram of a signal regeneration unit according to an embodiment of the present invention.
Figure 5 is an exemplary diagram of a discriminator according to an embodiment of the present invention.
Figure 6 is an exemplary diagram of a second receiver according to an embodiment of the present invention.
Figure 7 is a flowchart of an interference removal method using signal regeneration according to an embodiment of the present invention.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and can be implemented in various forms. The present embodiments are merely provided to ensure that the disclosure of the present invention is complete and to those skilled in the art to which the present invention pertains. It is provided to fully inform the person of the scope of the invention, and the scope of the invention is only defined by the claims.

In describing the embodiments of the present invention, detailed descriptions of well-known functions or configurations will be omitted except when actually necessary. The terms described below are terms defined in consideration of functions in the embodiments of the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, the definition should be made based on the contents throughout this specification.

Hereinafter used ‘…’ wealth', '… Terms such as 'unit' refer to a unit that processes at least one function or operation, and may be implemented as hardware, software, or a combination of hardware and software.

Figure 1 is a configuration diagram of a non-orthogonal multiple access system for uplink satellite communication according to an embodiment of the present invention.

Referring to FIG. 1, the Non-Orthogonal Multiple Access (NOMA) system of uplink satellite communication according to an embodiment of the present invention includes an interference removal device 100 using signal regeneration (hereinafter, “interference removal”). It may include a strong signal terminal 200 and a weak signal terminal 300 (referred to as “device 100”).

The interference removal device 100 according to an embodiment of the present invention can use a power domain-based non-orthogonal multiple access signal, and can use a difference in strength of the two signals of the non-orthogonal multiple access by a predetermined amount (dB). You can. In an embodiment of the present invention, among the two signals, a signal with a relatively large amplitude (dB) is referred to as a strong signal, and a signal with a relatively small amplitude (dB) is referred to as a weak signal. The interference cancellation device 100 may include a computer device mounted on a satellite that receives signals from a terrestrial terminal through an uplink.

The interference removal device 100 can simultaneously receive overlapping signals in which the signals of the strong signal terminal 200 and the weak signal terminal 300 overlap in a non-orthogonal multiple access method. As an example, the interference removal device 100 may receive the signal of the strong signal terminal 200 and the signal of the weak signal terminal 300 by overlapping them through a non-orthogonal multiple access traffic channel. As an example, the interference removal device 100 may estimate a frequency channel corresponding to a strong signal and a frequency channel corresponding to a weak signal through a time division multiple access (TDMA) type synchronization channel and perform synchronization.

The strong signal terminal 200 is a terminal that transmits a signal with relatively high power among signals of a non-orthogonal multiple access system to the interference removal device 100. The strong signal terminal 200 may transmit a strong signal through a traffic channel and transmit a synchronization signal corresponding to the strong signal through a synchronization channel.

The weak signal terminal 300 is a terminal that transmits a signal with relatively low power among signals of a non-orthogonal multiple access system to the interference removal device 100. The weak signal terminal 300 may transmit a weak signal through a traffic channel and a synchronization signal corresponding to the weak signal through a synchronization channel.

The strong signal terminal 200 and the weak signal terminal 300 operate a traffic channel and a synchronization channel simultaneously, and the modulation method of the strong signal terminal 200 and the weak signal terminal 300 may use a differential modulation method. .

The interference removal device 100 simultaneously receives an overlap signal and a synchronization signal, and to remove interference, first demodulates and decodes the strong signal, regenerates the extracted strong signal bit as the original signal, and removes the strong signal regenerated from the received overlap signal. Thus, the data of the weak signal can be demodulated. The specific configuration of the interference removal device 100 that performs this is shown in FIG. 2.

Figure 2 is a configuration diagram of an interference cancellation device 100 according to an embodiment of the present invention. The overall operation of the interference removal device 100 according to an embodiment of the present invention may be performed by one or more processors, and the one or more processors may control the functional blocks included in FIG. 2 to perform operations to be described later. .

Referring to FIG. 2, the interference removal apparatus 100 according to an embodiment of the present invention includes a first receiver 110, a channel estimation unit 120, a signal regeneration unit 130, a determination unit 140, and a second It may include a receiver 150.

The first receiver 110 may receive an overlapping signal including a strong signal and a weak signal in a non-orthogonal multiple access system, demodulate and decode the overlapping signal, and extract the strong signal bit. The first receiver 110 is a device that receives a traffic signal and performs offset correction, demodulation, and decoding, and may include the configuration of a general receiver such as the specific functional block illustrated in FIG. 3.

Figure 3 is an exemplary diagram of an interference removal device 100 using signal regeneration according to an embodiment of the present invention.

Referring to FIG. 3, the first receiver 110 according to one embodiment includes an automatic gain control unit (AGC) that maintains the size of the received overlapping signal within a certain range, and samples the signal output from the automatic gain control unit. Square root raised cosine filter unit (Square Root Raised Cosine Rx Filter), frequency offset correction unit, which performs frequency offset correction of the signal output by the square root raised cosine filter unit based on the offset frequency discrimination value to generate an offset-corrected overlapping signal, frequency A timing offset correction unit that corrects the timing offset for the signal output from the offset correction unit, a fine frequency offset correction unit that performs more precise frequency offset correction on the signal output from the timing offset correction unit, and a fine frequency offset correction unit that performs more precise frequency offset correction on the signal output from the fine frequency offset correction unit. It may include a phase offset correction unit that performs phase offset correction, a demodulation unit that demodulates the signal on which offset correction has been performed, and a channel decoding unit that performs channel decoding to extract bits of the signal.

The input signal and output signal passing through each functional block in FIG. 3 may be as shown in Table 1 below. However, the signals in Table 1 are only examples for understanding and are not limited thereto.

block input signal output signal automatic gain control Overlapping Traffic Signals (NOMA) Overlapping traffic signal (NOMA) with constant strength regardless of input strength Square Root Raised Cosine Filter Overlapping traffic signal (NOMA) with constant strength regardless of input strength Overlapping traffic signals with signal-to-noise ratio gain as a matched filter Frequency offset correction unit 1. Overlapping traffic signals with signal-to-noise ratio gain as a matched filter
2. Offset frequency discrimination value obtained through a strong synchronization signal Overlapping traffic signals corrected for subtle frequency offsets Timing offset correction unit Overlapping traffic signals corrected for subtle frequency offsets Overlapping traffic signals with corrected symbol timing offsets Fine frequency offset correction unit Overlapping traffic signals with corrected symbol timing offsets Overlapping traffic signals with fine frequency offset corrected Phase offset correction unit Overlapping traffic signals with fine frequency offset corrected Overlapping traffic signals with phase offset correction demodulator Overlapping traffic signals with phase offset correction Bit data of strong signal obtained through differential demodulation Channel decoding unit Bit data of strong signal obtained through differential demodulation Strong signal bits obtained through channel decoding channel estimation unit Synchronization signal (in the example of Figure 3, a synchronization signal with constant intensity, passed through a matched filter to obtain SNR gain, and corrected for fine frequency offset and symbol timing offset) Channel estimate value of synchronization signal of strong signal Signal regeneration unit 1. Bits of strong signal obtained through channel decoding
2. Channel estimates Regenerated strong traffic signal Determination unit 1. Regenerated strong traffic signal
2. Fine frequency correction unit output (in the example of Figure 3, an overlapping traffic signal with constant intensity, SNR gain obtained through a matched filter, and fine frequency offset corrected) Weak traffic signal second receiver Weak traffic signal bit of weak signal

The channel estimation unit 120 may receive a synchronization signal corresponding to a strong signal and determine a channel estimate value of the strong signal. The channel estimation unit 120 is a device that receives a synchronization signal, performs synchronization, and estimates an offset and a channel, and may include a general configuration such as the specific functional block illustrated in FIG. 3.

Referring again to FIG. 3, the channel estimation unit 120 according to one embodiment includes an automatic gain control (AGC) unit that maintains the size of the synchronization signal corresponding to the strong signal within a certain range, and the automatic gain control unit outputs A square root raised cosine filter unit that oversamples the signal, performs frequency offset correction on the signal output by the square root raised cosine filter unit, and adjusts the signal to the strong signal of the traffic channel based on the information contained in the synchronization signal. A frequency offset correction unit that determines the used frequency offset value, a timing offset correction unit that corrects the timing offset for the signal output by the frequency offset correction unit, and a channel that estimates the channel used for the strong signal based on the signal output by the timing offset correction unit. It may include a channel estimation unit that determines the estimated value.

The signal regeneration unit 130 may generate a regenerated strong signal using the strong signal bit output by the first receiver 110 and the channel estimate value output by the channel estimation unit 120.

Figure 4 is an exemplary diagram of the signal regeneration unit 130 according to an embodiment of the present invention.

Referring to FIG. 4, the signal regeneration unit 130 according to one embodiment includes a channel coding unit 131 for encoding a strong signal bit, a modulation unit 132 for modulating the encoded strong signal bit, and two components for the modulated signal. It may include two square root raised cosine filter units 133 and 134 that perform sampling (N oversampling, N/2 downsampling) and a channel filter unit 135 that generates a regenerative strong signal using the sampled signal and the channel estimate value. You can.

The input signal and output signal passing through each functional block in FIG. 4 may be as shown in the example in Table 2 below. However, the signals in Table 2 are only examples for understanding and are not limited thereto.

block input signal output signal Channel coding department Kang Shin-ho's beat channel coded bits Modulation section channel coded bits Differentially modulated symbols Square root raised cosine filter section (N oversample) Differentially modulated symbols Signal oversampled to N (same value as terrestrial transmitting terminal) Square root raised cosine filter section (N/2 downsample) Signal oversampled to N (same value as terrestrial transmitting terminal) A signal that is downsampled to N/2 and has 2 samples per symbol. Channel filter section 1. Signal downsampled to N/2 with 2 samples per symbol
2. Channel estimates Signal passed through filter using channel estimate as filter coefficient

The determination unit 140 generates a discrimination signal consisting of the sum or difference of the offset correction overlap signal and the regeneration strong signal based on the power difference value between the offset correction overlap signal and the regeneration strong signal to perform serial interference cancellation (SIC). You can. Since the strong signal and the weak signal pass through different Doppler channels, the discriminator 140 can apply a differential modulation method using the phase difference of two bits to perform more accurate demodulation. That is, in the differential modulation method, if an error occurs in one bit while regenerating a signal, a signal with a phase 180 degrees opposite to the original signal is generated from the next bit. To solve this problem, the determination unit 140 according to an embodiment of the present invention sets a standard for the sum and difference of the two signals to distinguish between cases where the average power of the difference value is greater than and less than a certain threshold value. This allows the signal to be switched.

Figure 5 is an exemplary diagram of the determination unit 140 according to an embodiment of the present invention.

Referring to FIG. 5, the determination unit 140 according to an embodiment includes a subtraction unit 141 that generates a first signal by subtracting the regenerative strong signal from the offset correction overlapping signal, and a first signal by summing the regenerative strong signal from the offset correction overlapping signal. A summing unit 142 that generates a 2 signal, a power measuring unit 143 that measures the power of the first signal, and if the power magnitude of the first signal is less than or equal to a predetermined threshold, outputs the first signal as a determination signal. , it may include a switch unit 144 that outputs the second signal as a determination signal when the power level of the first signal is greater than a predetermined threshold.

The second receiver 150 may extract a weak signal bit by demodulating and decoding the discrimination signal output by the determination unit 140. The second receiver 150 is a device that receives a traffic signal and performs offset correction, demodulation, and decoding, and may include a general configuration such as the specific functional block illustrated in FIG. 6.

Figure 6 is an exemplary diagram of a second receiver 150 according to an embodiment of the present invention.

Referring to FIG. 6, the second receiver 150 according to one embodiment includes an automatic gain control unit (AGC) that maintains the size of the input signal within a certain range and a sampling unit that samples the signal output from the automatic gain control unit. Square root raised cosine filter unit (Square Root Raised Cosine Rx Filter), frequency offset correction unit, which performs frequency offset correction of the signal output by the square root raised cosine filter unit based on the offset frequency discrimination value to generate an offset-corrected overlapping signal, frequency correction A timing offset correction unit that corrects the timing offset for the additionally output signal, a fine frequency offset correction unit that performs more precise frequency offset correction on the signal output from the timing offset correction unit, and a phase correction unit for the signal output from the fine frequency offset correction unit. It may include a phase offset correction unit that performs offset correction, a demodulation unit that demodulates the signal on which offset correction has been performed, and a channel decoding unit that performs channel decoding to extract bits of the signal.

The input signals and output signals passing through each functional block in FIG. 6 may be as shown in Table 3 below. However, the signals in Table 3 are only examples for understanding and are not limited thereto.

block input signal output signal automatic gain control weak signal Weak signal with constant intensity regardless of input intensity Square root round
cosine filter Weak signal with constant intensity regardless of input intensity Overlapping traffic signals with signal-to-noise ratio gain as a matched filter Frequency offset correction unit Overlapping traffic signals with signal-to-noise ratio gain as a matched filter Weak signal with frequency offset corrected Timing offset correction unit Weak signal with frequency offset corrected Weak signal with corrected symbol timing offset Fine frequency correction unit Weak signal with corrected symbol timing offset Weak signal with minor frequency offset corrected Phase offset correction unit Weak signal with minor frequency offset corrected Weak signal with phase offset corrected demodulator Weak signal with phase offset corrected Bit data of weak signal obtained through differential demodulation Channel decoding unit Bit data of weak signal obtained through differential demodulation Weak signal bits obtained through channel decoding

Figure 7 is a flowchart of an interference cancellation method according to an embodiment of the present invention. Each step of the interference removal method according to FIG. 7 can be performed by the interference removal device 100 described with reference to FIG. 2, and each step is described as follows.

In step S1010, the first receiver 110 may receive an overlapping signal including a strong signal and a weak signal in a non-orthogonal multiple access system, demodulate and decode the overlapping signal, and extract a strong signal bit.

In step S1020, the channel estimator 120 may receive a synchronization signal corresponding to a strong signal and determine a channel estimate value of the strong signal.

In step S1030, the signal regeneration unit 130 may generate a regenerated strong signal using the strong signal bit and channel estimate value.

In step S1040, the determination unit 140 may perform serial interference removal by generating a determination signal consisting of the sum or difference of the offset correction overlap signal and the regeneration strong signal based on the power difference value between the offset correction overlap signal and the regeneration strong signal.

In step S1050, the second receiver 150 may extract a weak signal bit by demodulating and decoding the discrimination signal.

Meanwhile, in addition to the steps shown in FIG. 7, the above-described frame first receiver 110, channel estimation unit 120, signal regeneration unit 130, determination unit 140, and second receiver 150 are performed in FIGS. As the embodiments that perform the operations described with FIG. 6 are configured in various ways, new steps performed by each functional block may be added to the steps in FIG. 7, and the configuration of additional steps and the components that are the subject of each step Since the operations for performing the corresponding steps are described in FIGS. 2 to 6, duplicate descriptions will be omitted.

According to the above-described embodiments, the embodiment of the present invention is excellent in low-orbit satellite communication where the Doppler effect is large, and when operating a power domain-based non-orthogonal multiple access system, serial interference removal is performed even in the section where the intensity difference between the two signals is low. Therefore, the difference in intensity between the two signals can be effectively operated over a wide range.

The above description is merely an illustrative explanation of the technical idea of the present invention, and those skilled in the art will be able to make various modifications and variations without departing from the essential quality of the present invention. Accordingly, the embodiments disclosed in this specification are not intended to limit the technical idea of the present invention, but rather to explain it, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention shall be interpreted in accordance with the claims below, and all technical ideas within the scope equivalent thereto shall be construed as being included in the scope of rights of the present invention.

100: Interference cancellation device
110: first receiver
120: Channel estimation unit
130: Signal regeneration unit
131: Channel coding unit
132: Modulation unit
133, 134: Square root raised cosine filter unit
135: Channel filter unit
140: Determination unit
141: Subtraction department
142: Addition section
143: Power measurement unit
144: switch part
150: second receiver
200: Strong signal terminal
300: Weak signal terminal

Claims (16)

A first receiver that receives overlapping signals including strong signals and weak signals in a non-orthogonal multiple access (NOMA) system, demodulates and decodes the overlapping signals to extract strong signal bits;
a channel estimation unit that receives a synchronization signal corresponding to the strong signal and determines a channel estimate value of the strong signal;
a signal regeneration unit that generates a regenerated strong signal using the strong signal bit and the channel estimate value;
A discriminator that performs serial interference cancellation (SIC) by generating a discrimination signal consisting of the sum or difference of the offset correction overlap signal and the regeneration strong signal based on the power difference value between the offset correction overlap signal and the regeneration strong signal; and
A second receiver that demodulates and decodes the discrimination signal to extract a weak signal bit,
The determination unit,
a subtraction unit that generates a first signal by subtracting the regenerated strong signal from the offset correction superimposed signal;
a summation unit that generates a second signal by summing the regenerated strong signal from the offset correction superimposed signal;
a power measuring unit that measures the power of the first signal; and
If the power magnitude of the first signal is less than or equal to the threshold, the first signal is output as the determination signal, and if the power magnitude of the first signal is greater than the threshold value, the second signal is output as the discrimination signal. Includes a switch unit;
Applying a differential modulation method using the phase difference between the strong signal bit and the weak signal bit,
Interference cancellation device.
According to paragraph 1,
The channel estimation unit,
an automatic gain control unit that maintains the magnitude of the synchronization signal corresponding to the strong signal within a certain range;
a square root raised cosine filter unit that samples the signal output from the automatic gain control unit;
a frequency offset correction unit that performs frequency offset correction on the signal output from the square root raised cosine filter unit;
a timing offset correction unit that corrects timing offset for the signal output from the frequency offset correction unit; and
Comprising a channel estimation unit that determines the channel estimate value for estimating a channel used by the strong signal based on the signal output by the timing offset correction unit,
Interference cancellation device.
According to paragraph 2,
The frequency offset correction unit,
Determining the frequency offset value used in the strong signal based on the synchronization signal,
Interference cancellation device.
According to paragraph 3,
The first receiver,
Performing frequency correction of the overlap signal based on the frequency offset value to generate the offset correction overlap signal and transmitting it to the determination unit.
Interference cancellation device.
According to paragraph 1,
The signal regeneration unit,
a channel coding unit that encodes the strong signal bits;
a modulator that modulates the encoded strong signal bits;
A square root raised cosine filter unit that samples the modulated signal; and
Comprising a channel filter unit that generates the regenerative strong signal using the sampled signal and the channel estimate value,
Interference cancellation device.
delete delete In the interference cancellation method performed by the interference cancellation device,
Receiving an overlapping signal including a strong signal and a weak signal in a non-orthogonal multiple access (NOMA) system, demodulating and decoding the overlapping signal to extract a strong signal bit;
Receiving a synchronization signal corresponding to the strong signal and determining a channel estimate value of the strong signal;
generating a regenerative strong signal using the strong signal bit and the channel estimate value;
Performing serial interference cancellation (SIC) by generating a discrimination signal consisting of the sum or difference of the offset correction overlap signal and the regeneration strong signal based on the power difference value between the offset correction overlap signal and the regeneration strong signal; and
Demodulating and decoding the discrimination signal to extract a weak signal bit,
The step of performing the serial interference cancellation is,
generating a first signal by subtracting the regenerated strong signal from the offset correction superimposed signal;
generating a second signal by adding the regenerated strong signal to the offset correction superimposed signal;
measuring the power of the first signal; and
If the power magnitude of the first signal is less than or equal to the threshold, the first signal is output as the determination signal, and if the power magnitude of the first signal is greater than the threshold value, the second signal is output as the discrimination signal. Including steps;
Applying a differential modulation method using the phase difference between the strong signal bit and the weak signal bit,
How to eliminate interference.
According to clause 8,
The step of determining the channel estimate value is,
maintaining the size of the synchronization signal corresponding to the strong signal within a certain range and outputting it;
sampling the output signal;
performing frequency offset correction on the output signal;
correcting timing offset for the output signal; and
Comprising the step of determining the channel estimate value for estimating a used channel of the strong signal based on the output signal,
How to eliminate interference.
According to clause 9,
The step of determining the channel estimate value is,
Further comprising the step of determining the frequency offset value used for the strong signal based on the synchronization signal,
How to eliminate interference.
According to clause 10,
The step of extracting the strong signal bit is,
Comprising the step of performing frequency correction of the overlap signal based on the frequency offset value to generate the offset correction overlap signal,
How to eliminate interference.
According to clause 8,
The step of generating the regenerative strong signal is,
Encoding the strong signal bits;
Modulating the encoded strong signal bits;
sampling the modulated signal; and
Generating the regenerative strong signal using the sampled signal and the channel estimate,
How to eliminate interference.
delete delete A computer-readable recording medium storing a computer program,
Receiving an overlapping signal including a strong signal and a weak signal in a non-orthogonal multiple access (NOMA) system, demodulating and decoding the overlapping signal to extract a strong signal bit;
Receiving a synchronization signal corresponding to the strong signal and determining a channel estimate value of the strong signal;
generating a regenerative strong signal using the strong signal bit and the channel estimate value;
Performing serial interference cancellation (SIC) by generating a discrimination signal consisting of the sum or difference of the offset correction overlap signal and the regeneration strong signal based on the power difference value between the offset correction overlap signal and the regeneration strong signal; and
Demodulating and decoding the discrimination signal to extract a weak signal bit,
The step of performing the serial interference cancellation is,
generating a first signal by subtracting the regenerated strong signal from the offset correction superimposed signal;
generating a second signal by adding the regenerated strong signal to the offset correction superimposed signal;
measuring the power of the first signal; and
If the power magnitude of the first signal is less than or equal to the threshold, the first signal is output as the determination signal, and if the power magnitude of the first signal is greater than the threshold value, the second signal is output as the discrimination signal. Including steps;
Applying a differential modulation method using the phase difference between the strong signal bit and the weak signal bit,
A computer-readable recording medium comprising instructions for causing a processor to perform an interference cancellation method.
A computer program stored on a computer-readable recording medium,
Receiving an overlapping signal including a strong signal and a weak signal in a non-orthogonal multiple access (NOMA) system, demodulating and decoding the overlapping signal to extract a strong signal bit;
Receiving a synchronization signal corresponding to the strong signal and determining a channel estimate value of the strong signal;
generating a regenerative strong signal using the strong signal bit and the channel estimate value;
Performing serial interference cancellation (SIC) by generating a discrimination signal consisting of the sum or difference of the offset correction overlap signal and the regeneration strong signal based on the power difference value between the offset correction overlap signal and the regeneration strong signal; and
Demodulating and decoding the discrimination signal to extract a weak signal bit,
The step of performing the serial interference cancellation is,
generating a first signal by subtracting the regenerated strong signal from the offset correction superimposed signal;
generating a second signal by adding the regenerated strong signal to the offset correction superimposed signal;
measuring the power of the first signal; and
If the power magnitude of the first signal is less than or equal to the threshold, the first signal is output as the determination signal, and if the power magnitude of the first signal is greater than the threshold value, the second signal is output as the discrimination signal. Including steps;
Applying a differential modulation method using the phase difference between the strong signal bit and the weak signal bit.
A computer program comprising instructions for causing a processor to perform an interference cancellation method.

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