KR102094428B1 - Method and System for Non-Orthogonal Multiple Access Communication Using Space-Time Line Code Based Phase Steering - Google Patents

Abstract

The present invention relates to a non-orthogonal multiple access communication method using space time line code based on a phase steering, and a system thereof. The non-orthogonal multiple access communication method using space time line code based on a phase steering according to one embodiment of the present invention, for a method for communicating a plurality of transmitters having one antenna, respectively, to a receiver having a plurality of antennas in a non-orthogonal multiple access (NOMA) method, comprises the steps of: allowing the transmitters to apply different phases to a modulating symbol in order to have different constellation for each modulating symbol; allowing the transmitters to use channel information for the modulating symbol having different phases applied thereto to encode the same in a space time line code (STLC) method, and transmit the same to the receiver simultaneously; and allowing the receiver to combine a plurality of signals received through the multiple antennas without channel information and decode an information symbol. Accordingly, the present invention can improve a total transmission rate.

Description

Method and System for Non-Orthogonal Multiple Access Communication Using Space-Time Line Code Based Phase Steering}

The present invention relates to a non-orthogonal multiple access communication method and system using phase-steering-based spatio-temporal line coding. In particular, in an uplink NOMA system, a phase-steering-based spatio-temporal line coding technique is used, so that only a transmitting device knows channel information. It relates to a non-orthogonal multiple access communication method and system using phase-steering-based space-time line coding capable of obtaining diversity.

In a cellular network, a non-orthogonal multiple access (NOMA) system, which is a technology for increasing frequency efficiency and cell capacity, transmits a signal to a single receiving device at the same frequency by two or more transmitting devices. Is a wireless communication system that detects each signal in terms of power for a received signal in which two or more signals overlap.

In the NOMA system including such a multi-antenna receiving apparatus, maximum diversity can be obtained only when the receiving apparatus knows channel information.

However, in a conventional wireless communication system including a multi-antenna receiving apparatus, when only the transmitting apparatuses know the channel information, the maximum ratio transmission (MRT) technique that can be used is one receiving antenna of the receiving apparatus in the transmitting apparatus. The maximum diversity cannot be obtained because the signal is encoded based only on the channel information. Therefore, good performance cannot be expected.

Accordingly, in the NOMA system, if channel information is known only from the transmitting device, additional research is needed on a communication method that can obtain maximum diversity.

In this regard, Korean Registered Patent No. 10-1275851, entitled " Transmission and reception apparatus and method based on space-time block encoding using U (ｑ) (ｎ).

Technical problem to be solved by the present invention is a non-orthogonal multiple access communication method using a phase steering-based space-time line code capable of obtaining maximum diversity even when only a transmitting device knows channel information in an uplink non-orthogonal multiple access system and the same It is to provide a system.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person skilled in the art from the following description.

In order to solve the above technical problem, a non-orthogonal multiple access communication method using a phase steering-based space-time line code according to an embodiment of the present invention includes a plurality of transmitting devices each having one antenna and a receiving device having a plurality of antennas. A method in which a device communicates in a non-orthogonal multiple access (NOMA) method, wherein the plurality of transmitting devices have different phases in the modulation symbol so that they have different constellations for each modulation symbol. Applying, the plurality of transmitting devices, using the channel information for the modulation symbols to which the different phases are applied, encoding in a space-time line code (STLC) method, and simultaneously transmitting to the receiving device, the receiving device And combining a plurality of signals received through the plurality of antennas without channel information to demodulate information symbols.

Preferably, prior to the step of encoding by the space-time line coding method, the receiving device allocates different phase angles for phase steering of each of the plurality of transmitting devices, and includes information about the assigned phase angles. The method may further include transmitting a pilot signal to the plurality of transmitting devices, and each of the plurality of transmitting devices acquires channel information from the pilot signal and sets the obtained channel information and the phase angle, respectively. have.

Preferably, in the step of applying different phases to the modulation symbols such that the plurality of transmission devices have different constellations for each modulation symbol, the plurality of transmission devices may set each information symbol to a predetermined value. The method may include modulating a modulation method to output a modulation symbol, and applying a different phase to each modulation symbol by the plurality of transmitting devices.

Preferably, in the step of simultaneously transmitting to the receiving device, when the plurality of transmitting devices are two, and each of two information symbols is space-time line-encoded, the signal transmitted to the receiving device may be expressed by the following equation: have.

 [Mathematics]

는 i번째 송신장치의 j번째 타임슬롯에서 변조된 변조 심벌,

는 i번째 송신장치의 j번째 타임슬롯에 송신할 시공간 선 부호화된 심볼,

는 i번째 송신장치에서부터 수신장치의 k번째 안테나까지의 레일-레이 페이딩 채널,

는 위상 조향을 위한 임의의 위상각을 의미함.here,

Is a modulation symbol modulated in the j-th timeslot of the i-th transmitter,

Is a space-time line-encoded symbol to be transmitted in the j-th time slot of the i-th transmission device,

Is a rail-ray fading channel from the i th transmitting device to the k th antenna of the receiving device,

Means an arbitrary phase angle for phase steering.

)는 아래 수학식으로 정의될 수 있다. Preferably, in the step of demodulating the information symbol, the combined signal without the channel information (

) May be defined by the following equation.

 [Mathematics]

와

는 수신장치의 k번째 안테나로 j번째 타임슬롯에 수신한 신호와 잡음,

는 i번째 송신장치의 j번째 타임슬롯에 변조된 변조 심벌,

는

번째 송신장치의 무선 채널의 노름을 의미함.here,

Wow

Is the kth antenna of the receiving device, the signal and noise received in the jth timeslot,

Is a modulation symbol modulated in the j-th timeslot of the i-th transmitter,

The

It means the gambling of the wireless channel of the first transmitting device.

Preferably, the information symbol can be demodulated by the following equation according to joint maximum likelihood detection.

[Mathematics]

는 수신장치에서 복조한 첫번째 송신장치의 j번째 정보 심볼,

는 수신장치에서 복조한 두번째 송신장치의 j번째 정보 심볼을 의미하며

는 변조된 신호의 집합을 의미함.here,

Is the jth information symbol of the first transmitting device demodulated by the receiving device,

Denotes the j-th information symbol of the second transmitting device demodulated by the receiving device,

Means a set of modulated signals.

The transmission apparatus according to another embodiment of the present invention for solving the above technical problem, a modulator for modulating an antenna, an information symbol with a predetermined modulation method, and outputting a modulation symbol, a phase for applying a preset phase to the modulation symbol A phase steerer, a space-time line code (STLC) encoder that encodes the phase-steered modulation symbol using a space-time line code (STLC) method, receives the coded STLC symbol through the antenna It includes a transmitter for transmitting to the device.

Preferably, the receiver may further include a setting unit that receives a pilot signal including channel information and a phase angle for phase steering, and provides a phase angle to the phase steering unit and the channel information to the STLC encoder. have.

A receiving apparatus according to another embodiment of the present invention for solving the above technical problem, a plurality of antennas, a receiving unit for receiving a signal through the plurality of antennas, linearly combines the received plurality of signals to obtain a linear combined signal A STLC decoder to generate, a detection unit that detects a modulation symbol using a joint maximum likelihood (ML) detection technique, and demodulates the detected modulation symbol by a predetermined demodulation method to output an information symbol It includes a demodulator.

Preferably, when a plurality of transmitting devices exist in the coverage of the receiving device, a different phase angle is allocated for phase steering of each of the plurality of transmitting devices, and a pilot including information on the assigned phase angle It may further include a pre-processing unit for transmitting a signal to the plurality of transmission devices.

In order to solve the above technical problem, a non-orthogonal multiple access system using phase steering-based space-time line coding according to another embodiment of the present invention includes a plurality of transmitting devices each having one antenna and a receiving device having a plurality of antennas. In a method in which a device communicates in a non-orthogonal multiple access (NOMA) method, different phases are applied so as to have different constellations for a plurality of modulation symbols, and space-time line codes are used using channel information. (STLC) method, and a plurality of transmitting devices, a plurality of antennas are provided for transmitting to a receiving device in a non-orthogonal multiple access (NOMA) method, a plurality of received through the plurality of antennas And a receiving device for demodulating information symbols by combining signals without channel information.

According to the present invention, when using a phase-steering-based space-time line coding technique in a NOMA system for a base station (region, receiving device) that requires high frequency efficiency in an uplink cellular network, more terminals due to more than twice the frequency efficiency (Transmission device) can be accommodated, and for a base station using multiple antennas, terminals can achieve maximum diversity, thereby improving the total transmission rate.

In addition, when there are many terminals serving in the base station, it is possible to distribute a computational amount to be handled by the base station, thereby reducing the load on the base station.

In addition, even if a channel is not known to a receiving apparatus having multiple antennas, the signal of the transmitting apparatus can be decoded by simple calculation of the received signals by transmitting the signal encoded by the space-time line coding technique.

In addition, as a method for improving performance, it can be implemented by simply controlling the phase of the signal without controlling transmission power or requiring complicated calculation.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

값이 0일 때,

의 성상도를 설명하기 위한 예시도이다.
도 7은 본 발명의 일 실시예에 따른 위상 조향을 위한 위상각

값이 0이 아닐 때,

의 성상도를 설명하기 위한 예시도이다.
도 8은 본 발명의 일 실시예에 따른 여러 조향 위상각에 대한 QPSK 신호에 신호 대 잡음비에 따른 비트 오류율 성능을 비교한 그래프이다.1 and 2 are diagrams for explaining a non-orthogonal multiple access system using phase-steering-based space-time linear encoding according to an embodiment of the present invention.
3 is a view for explaining a transmitting apparatus in an uplink non-orthogonal multiple access system using a phase steering-based space-time line code according to an embodiment of the present invention.
4 is a diagram for explaining a receiving apparatus in an uplink non-orthogonal multiple access system using a phase steering-based space-time line code according to an embodiment of the present invention.
5 is a view for explaining a non-orthogonal multiple access communication method using phase-steering-based spatio-temporal linear encoding according to an embodiment of the present invention.
6 is a phase angle for phase steering according to an embodiment of the present invention

When the value is 0,

It is an example for explaining the constellation of.
7 is a phase angle for phase steering according to an embodiment of the present invention

When the value is not 0,

It is an example for explaining the constellation of.
8 is a graph comparing bit error rate performance according to signal-to-noise ratio to QPSK signals for various steering phase angles according to an embodiment of the present invention.

The present invention can be applied to various changes and may have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing each drawing, similar reference numerals are used for similar components.

Terms such as first, second, A, and B can be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from other components. For example, the first component may be referred to as a second component without departing from the scope of the present invention, and similarly, the second component may be referred to as a first component. The term and / or includes a combination of a plurality of related described items or any one of a plurality of related described items.

When an element is said to be "connected" or "connected" to another component, it is understood that other components may be directly connected to or connected to the other component, but may exist in the middle. It should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that no other component exists in the middle.

The terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "include" or "have" are intended to indicate the presence of features, numbers, steps, actions, components, parts or combinations thereof described herein, one or more other features. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. Terms such as those defined in a commonly used dictionary should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined in the present application. Does not.

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

1 and 2 are diagrams for explaining a non-orthogonal multiple access system using space-time line coding according to an embodiment of the present invention.

1 and 2, a non-orthogonal multiple access system using space-time line coding according to an embodiment of the present invention includes a plurality of transmitting devices 100 and a receiving device 200 with a plurality of antennas. .

After applying different phases to a plurality of modulation symbols, the transmitting apparatus 100 encodes the space-time line coding technique using channel information, and receives the apparatus through a non-orthogonal multiple access (NOMA) method. (200). The transmission device 100 may include, for example, an IoT device, a sensor, a wireless device such as a smartphone.

The receiving apparatus 200 demodulates information symbols by linearly combining a plurality of signals received through a plurality of antennas without channel information.

The receiving device 200 may be, for example, a base station.

On the other hand, the present invention relates to a non-orthogonal multiple access system for transmitting a signal in an uplink, there are a plurality of transmission devices 100 in the transmission range (coverage) of the base station 200, but for convenience of description, the following description There are two devices, and the receiving device (base station) 200 will be described as being limited to two antennas. Accordingly, the present invention considers an uplink cellular radio communication environment in which a base station 200 having two transmitting devices 100a and 100b and two receiving antennas is present, and simultaneously transmits and receives signals at the same frequency. It is about.

The receiving device 200 does not know the channel information, and each transmitting device 100a, 100b acquires channel information from the pilot signal of the receiving device 200, and uses only the channel information to use the space-time line code (STLC) to maximize Diversity can be obtained. Accordingly, the receiving device 200 transmits a pilot signal for channel estimation, and each transmitting device 100a and 100b can estimate channel information from the pilot signal.

)로 조향하고 STLC를 이용하여 부호화된 두 개의 신호를 전송한다. 이때, 두 개의 신호는 각 송신장치(100a, 100b)에서 기지국(200)까지의 채널 정보를 이용하여 부호화된다. 이처럼, 송신장치(100a, 100b) 중 하나의 송신장치(100a)는 심볼의 성상도를 특정 각도(

)로 회전시켜 신호를 전송함으로써, 최대 다이버시티를 얻게 하여 비트 오류율 성능을 향상시킬 수 있다.The first and second transmitting devices 100a and 100b apply a phase steering technique to the modulated signal during the first and second timeslots to determine the phase at a specific angle (

) And transmits two signals encoded using STLC. At this time, the two signals are encoded using channel information from each of the transmitting devices 100a and 100b to the base station 200. As described above, one of the transmitting devices 100a and 100b transmits the constellation of the symbol at a specific angle (

) To transmit the signal to obtain maximum diversity, thereby improving bit error rate performance.

The receiving device 200 simultaneously receives signals of the first and second transmitting devices 100a and 100b by NOMA, and uses the characteristics of STLC to receive signals received by two receiving antennas during the first and second time slots. Since the phase difference between the transmitting and receiving terminals can be compensated for the two signals constituting in a linear combination of them, decoding of each signal is possible.

Hereinafter, the operation of the transmitting apparatus 100 and the receiving apparatus 200 according to the present invention will be described.

The first and second transmission devices 100a and 100b each have two information symbols, and modulate each information symbol. That is, the first transmission device 100a generates quadrature amplitude modulation (QAM) of two information symbols to generate modulation symbols x _{1, 1} and x _1,2 , and the second transmission device 100 b includes two information symbols. Modulation symbols x _2,1 and x _2,2 are generated by orthogonal amplitude modulation of the two pieces of data.

) 회전시키고 채널 정보를 이용하여 STLC로 부호화하여, STLC 심볼을 생성한다. 따라서 제1 송신장치(100a)와 제2 송신장치(100b)는 아래 수학식 1과 같은 STLC 심볼을 생성한다. In addition, the first and second transmitting devices 100a and 100b are configured to set the phase to a specific angle (so that each modulation symbol has a different constellation.

) Rotate and encode to STLC using channel information to generate STLC symbols. Accordingly, the first transmission device 100a and the second transmission device 100b generate STLC symbols as shown in Equation 1 below.

[Equation 1]

는 i번째 송신장치의 j번째 타임슬롯에서 변조된 변조 심벌,

는

i번째 송신장치의 j번째 타임슬롯에 송신할 시공간 선 부호화된 STLC 심볼,

는 i번째 송신장치에서부터 수신장치의 k번째 안테나까지의 레일-레이 페이딩 채널,

는 위상 조향을 위한 임의의 위상각을 의미한다. 채널은 제1 및 제2 타임슬롯동안 변하지 않고 모든 채널은

분포를 따른다고 가정한다.here,

Is a modulation symbol modulated in the j-th timeslot of the i-th transmitter,

The

a space-time line-encoded STLC symbol to be transmitted in the j-th timeslot of the i-th transmitter,

Is a rail-ray fading channel from the i th transmitting device to the k th antenna of the receiving device,

Means an arbitrary phase angle for phase steering. Channels do not change during the first and second timeslots and all channels

Assume that you follow the distribution.

When the STLC symbol is generated as shown in Equation 1, the first and second transmission devices 100a and 100b sequentially transmit the first STLC symbol and the second STLC symbol through the antenna in the first and second timeslots, respectively. . That is, the first and second transmitting devices 100a and 100b simultaneously transmit the first STLC symbols s _1,1 and the first STLC symbols s _2,1 in the first timeslot, and the second STLC in the second timeslot. The symbols s _1,2 and the first STLC symbols s ₂ and ₂ are transmitted simultaneously. As described above, the first and second transmitting devices 100a and 100b continuously transmit two STLC symbols during the first timeslot and the second timeslot.

As described above, since the first and second transmitting devices 100a and 100b simultaneously transmit signals at the same frequency during one timeslot, the signals received from the receiving device 200 over the first and second timeslots are Equation 2 below may be the same. That is, when the received signal from the k-th antenna (the k-th antenna) is represented by y _{k, j} in the j-th timeslot (the j-th timeslot), the four received signals can be expressed as Equation 2 according to Table 1 below. You can.

[Table 1]

[Equation 2]

와

는 수신장치의 k번째 안테나로 j번째 타임슬롯에 수신한 신호와 잡음을 의미한다.here,

Wow

Denotes the signal and noise received in the j-th timeslot as the k-th antenna of the receiving device.

)를 생성한다. The receiving device 200 linearly combines four received signals of Equation 2 to decode symbols transmitted from the transmitting device 100. That is, the receiving device 200 linearly combines the four received signals to form a linear combined signal (Equation 3 below)

).

[Equation 3]

Since the transmission signals of the first and second transmission devices 100a and 100b are superimposed on the linear combination signal of Equation 3, the reception device 200 uses a joint maximum likelihood (ML) detection technique. Decrypt each symbol. That is, the receiving device 200 restores each symbol as shown in Equation 4 below.

[Equation 4]

는 수신장치에서 복조한 첫번째 송신장치의 j번째 정보 심볼,

는 수신장치에서 복조한 두번째 송신장치의 j번째 정보 심볼,

는 소정의 변조 심벌의 집합을 의미한다.here,

Is the jth information symbol of the first transmitting device demodulated by the receiving device,

Is the jth information symbol of the second transmitter demodulated by the receiver,

Means a set of predetermined modulation symbols.

3 is a view for explaining a transmitting apparatus in an uplink non-orthogonal multiple access system using a phase steering-based space-time line code according to an embodiment of the present invention.

Referring to FIG. 3, in an uplink non-orthogonal multiple access system using a space-time line code according to an embodiment of the present invention, the transmitter 100 includes a modulator 110, a phase steerer 120, It includes an STLC encoder 130, a transmitter 140, and an antenna 150.

The transmitting apparatus 100 according to the present invention receives a pilot signal including a phase angle for phase steering from a receiving device, obtains channel information from the pilot signal, and provides the obtained phase angle to the phase steering unit 120 And, it may further include a setting unit (not shown) for providing the channel information to the STLC encoder 130.

The modulator 110 modulates the input information symbol by a predetermined modulation method and outputs a modulation symbol. At this time, as a modulation method, for example, among a variety of modulation methods such as BPSK (Binary Phase Shift Keying), QPSK (Quadrature Phase Shift Keying), QAM (Quadrature Amplitude Modulation), PAM (Pulse Amplitude Modulation), and PSK (Phase Shift Keying). Either can be applied. Preferably, the information symbol can be modulated in QAM.

)만큼 조향시킨다.The phase steering unit 120 applies a preset phase to the modulation symbols x _1,1 and x _1,2 and x _2,1 and x _2,2 modulated by the modulation unit 110. That is, the phase steering unit 120, when the phase angle set by the setting unit, the modulation symbol modulated by the modulation unit 110 corresponds to the angle (

).

The STLC encoder 130 performs space-time line encoding on the modulation symbol output from the phase steering unit 120 using channel information. That is, the STLC encoder 130 uses the modulated two modulation symbols x _{1, 1} and x _1,2 and x _2,1 and x _2,2 using channel information during the first timeslot and the second timeslot, respectively. It encodes in the STLC method, and outputs an STLC symbol.

The transmitter 140 transmits the STLC symbols s _{1, 1} and s _1,2 generated by the STLC encoder 130 to the receiving device through the antenna 150. At this time, the transmitting unit 140 transmits the first STLC symbols s _1,1 and s _2,1 during the first timeslot, and transmits the second STLC symbols s _1,2 and s _2,2 during the second timeslot. .

4 is a diagram for explaining a receiving apparatus in an uplink non-orthogonal multiple access system using a phase steering-based space-time line code according to an embodiment of the present invention.

FIG. 4 illustrates that in the uplink non-orthogonal multiple access system using space-time line codes according to an embodiment of the present invention, the receiving device 200 includes a plurality of antennas 210, a receiving unit 220, an STLC decoder 230, and a detecting unit ( 240), a demodulator 250.

In addition, when a plurality of transmitting devices exist in their coverage, the receiving device 200 according to the present invention allocates different phase angles for phase steering of each of the plurality of transmitting devices, and for the assigned phase angle It may further include a pre-processing unit (not shown) for transmitting the pilot signal including the information to a plurality of transmission devices.

The receiver 220 receives signals through a plurality of antennas 210.

The STLC decoder 230 linearly combines signals received through the plurality of antennas 210 to generate a linear combined signal. The linear combined signal is expressed by Equation 3.

The detector 240 detects a modulation symbol by using a joint maximum likelihood (ML) detection technique of the linear combined signal generated by the STLC decoder 230. That is, the detection unit 240 detects a modulation symbol using Equation (4). Then, a modulation symbol such as Equation 5 below can be detected.

[Equation 5]

The demodulator 250 demodulates the modulation symbol detected by the detector 240 in a predetermined demodulation method and outputs the original information symbol of the transmitter. At this time, as a demodulation method, for example, among various demodulation methods such as binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM), pulse amplitude modulation (PAM), and phase shift keying (PSK). Either can be applied. Preferably, the original information symbol can be demodulated in QAM.

5 is a view for explaining a non-orthogonal multiple access communication method using phase-steering-based spatio-temporal linear encoding according to an embodiment of the present invention.

Referring to FIG. 5, the first and second transmitting devices modulate a predetermined modulation method for each information symbol and output modulation symbols (S510). At this time, it is assumed that the phase angle for phase steering is set in the first transmission device, and the phase angle is not set in the second transmission device.

)만큼 조향시키고(S520), 시공간 선 부호화하여 STLC 심볼을 생성한다(S530). 이때, 제2 송신장치에는 위상각이 설정되어 있지 않으므로, 변조 심볼을 시공간 선 부호화하여 STLC 심볼로 생성한다(S530).When the step S510 is performed, the first transmission device generates an modulation symbol corresponding to the phase angle (

) (S520) and space-time line encoding to generate an STLC symbol (S530). At this time, since the phase angle is not set in the second transmission device, the modulation symbols are space-time line-encoded to generate STLC symbols (S530).

When step S530 is performed, the first and second transmitting devices simultaneously transmit the generated STLC symbols to the receiving device (S540).

Then, the reception device receives signals transmitted by the first and second transmission devices through a plurality of antennas, and linearly combines the received signals to generate a linear combined signal (S550).

Then, the receiving device demodulates the information symbol using a joint maximum likelihood (ML) detection technique for the linear combined signal (S560).

값이 0일 때,

의 성상도를 설명하기 위한 예시도, 도 7은 본 발명의 일 실시예에 따른 위상 조향을 위한 위상각

값이 0이 아닐 때,

의 성상도를 설명하기 위한 예시도, 도 8은 본 발명의 일 실시예에 따른 여러 조향 위상각에 대한 QPSK 신호에 신호 대 잡음비에 따른 비트 오류율 성능을 비교한 그래프이다. 6 is a phase angle for phase steering according to an embodiment of the present invention

When the value is 0,

Exemplary diagram for explaining the constellation of Figure, Figure 7 is a phase angle for phase steering according to an embodiment of the present invention

When the value is not 0,

8 is a graph comparing bit error rate performance according to signal-to-noise ratio to QPSK signals for various steering phase angles according to an embodiment of the present invention.

일 때 성상도의 신호 점들이 겹치는 부분이 생성되어 신호의 성능을 크게 떨어뜨리며 이는 도 8의 비트 오류율 측면에 대해서 확인할 수 있다. 도 7을 참조하면, 성상도의 신호 점간의 최소 거리가 더 증가한 것을 확인할 수 있다. 이는 한 송신장치에 대해서 성상도의 위상을 임의의 각도로 조향함으로 인해 의도적으로 신호 점들의 겹침을 회피하였기 때문이다. 이 결과에 대한 성능은 도 8의 비트 오류율 측면에 대해서 확인할 수 있으며

가 22.5°일 때 최적의 값임을 수치적으로 확인하였다. 추가로 높은 신호 대 잡음비 구간에서는 직교 다중화 접속(Orthogonal Multiple Access, OMA)과 거의 동일한 성능을 확인할 수 있다.Referring to FIG. 6, the larger the minimum distance between signal points of constellations, which is one of the measures of communication performance, the better the performance. But

In this case, a portion where signal points of the constellation overlap is generated, which significantly degrades the performance of the signal, which can be confirmed with respect to the bit error rate aspect of FIG. 8. Referring to FIG. 7, it can be seen that the minimum distance between the signal points of the constellation is further increased. This is because the overlapping of signal points is intentionally avoided by steering the phase of the constellation with an arbitrary angle for one transmission device. The performance of this result can be confirmed with respect to the bit error rate aspect of FIG. 8,

It was numerically confirmed that is an optimal value when is 22.5 °. In the additional high signal-to-noise ratio section, almost the same performance as orthogonal multiple access (OMA) can be confirmed.

So far, the present invention has been focused on the preferred embodiments. Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered in terms of explanation, not limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the equivalent range should be interpreted as being included in the present invention.

100: transmitting device
110: modulator
120: STLC encoder
130: phase steering unit
140: transmitting unit
150, 210: antenna
200: receiving device
220: receiver
230: STLC decoder
240: detection unit
250: demodulator

Claims (11)

A method of communicating in a non-orthogonal multiple access (NOMA) method by a plurality of transmitting devices each having one antenna and a receiving device having multiple antennas,
Applying a different phase to the modulation symbols such that the plurality of transmission devices have different constellations for each modulation symbol;
The plurality of transmitting apparatuses encoding channel-modulated symbols with different phases by using space-time line code (STLC), and simultaneously transmitting them to the receiving apparatus; And
The receiving device demodulates information symbols by combining a plurality of signals received through the plurality of antennas without channel information.
A non-orthogonal multiple access communication method using phase steering-based space-time line coding. According to claim 1,
Before the step of encoding with the space-time line coding method,
The receiving device respectively assigning different phase angles for phase steering of each of the plurality of transmitting devices, and transmitting a pilot signal including information on the assigned phase angles to the plurality of transmitting devices; And
Each of the plurality of transmitting apparatuses further comprises obtaining channel information from the pilot signal, and setting the obtained channel information and the phase angle, respectively, and non-orthogonal multiple access communication method using space-time line coding. . According to claim 1,
The step of applying different phases to the modulation symbols such that the plurality of transmission devices have different constellations for each modulation symbol,
The plurality of transmitting devices modulating each information symbol by a predetermined modulation method to output a modulation symbol; And
The plurality of transmitting apparatus, applying a different phase to each modulation symbol, characterized in that it comprises a phase steering-based space-time line coding non-orthogonal multiple access communication method. According to claim 1,
In the step of simultaneously transmitting to the receiving device,
When the plurality of transmission apparatuses are two and each of the two information symbols is space-time line-encoded, a signal transmitted to the reception apparatus is represented by the following equation, and non-orthogonal multiplexing using phase-steering-based space-time line encoding. Connection communication method.
[Mathematics]

here,

Is a modulation symbol modulated in the j-th timeslot of the i-th transmitter,

Is a space-time line-encoded symbol to be transmitted in the j-th time slot of the i-th transmission device,

Is a rail-ray fading channel from the i th transmitting device to the k th antenna of the receiving device,

Means an arbitrary phase angle for phase steering. According to claim 4,
In the step of demodulating the information symbol,
The combined signal without the channel information (

) Is a non-orthogonal multiple access communication method using phase-steering-based space-time line coding, characterized by being defined by the following equation.
[Mathematics]

here,

Wow

Is the kth antenna of the receiving device, the signal and noise received in the jth timeslot,

Is a modulation symbol modulated in the j-th timeslot of the i-th transmitter,

The

It means the gambling of the wireless channel of the first transmitting device. The method of claim 5,
The information symbol is demodulated by the following equation according to the joint maximum likelihood detection (joint Maximum Likelihood Detection), non-orthogonal multiple access communication method using phase-steering-based space-time line coding.
[Mathematics]

here,

Is the jth information symbol of the first transmitting device demodulated by the receiving device,

Denotes the j-th information symbol of the second transmitting device demodulated by the receiving device,

Means a set of modulated signals. antenna;
A modulator for modulating the information symbol by a predetermined modulation method and outputting a modulation symbol;
A phase steerer applying a preset phase to the modulation symbol;
A space-time line code (STLC) encoder for encoding the phase-steered modulation symbol using channel information in a space-time line code (STLC) method; And
Transmitter for transmitting the coded STLC symbol to the receiving device through the antenna
Transmission device comprising a. The method of claim 7,
And receiving a pilot signal including channel information and a phase angle for phase steering from the receiving device, and further comprising a setting unit configured to provide the phase angle to the phase steering unit and the channel information to the STLC encoder. Device. A plurality of antennas;
A receiver configured to receive signals through the plurality of antennas;
An STLC decoder that linearly combines the received plurality of signals to generate a linear combined signal;
A detection unit that detects a modulation symbol using a joint maximum likelihood (ML) detection technique for the linear combined signal; And
A demodulator that demodulates the detected modulation symbol by a predetermined demodulation method and outputs information symbols.
Receiving device comprising a. The method of claim 9,
When a plurality of transmission devices exist in the coverage of the reception device, different phase angles are allocated for phase steering of each of the plurality of transmission devices, and a plurality of pilot signals including information on the assigned phase angles are transmitted to the plurality of transmission devices. Further comprising a pre-processing unit for transmitting to the transmitting device. A method of communicating in a non-orthogonal multiple access (NOMA) method by a plurality of transmitting devices each having one antenna and a receiving device having multiple antennas,
Different phases are applied to a plurality of modulation symbols to have different constellations, and the channel information is used to encode in space-time line code (STLC) and non-orthogonal multiple access (NOMA). A plurality of transmitting devices transmitting to the receiving device; And
A receiving device provided with a plurality of antennas, combining a plurality of signals received through the plurality of antennas without channel information, and demodulating information symbols
A non-orthogonal multiple access system using space-time line coding based on phase steering including a.

Images