KR102399977B1 - Method for transmitting wireless communication signals - Google Patents

Abstract

The present invention relates to a method for transmitting a wireless communication signal, wherein a transmission signal is transmitted using a Mode Division Multiple Access (MDMA) method according to an Orbital Angular Momentum (OAM) mode in a base station using a Large Intelligent Surface (LIS) method. ) to the device, and by using a plurality of reflective elements in the LIS device to reflect the transmission signal to a near user and a far user, respectively, it is possible to improve the communication channel capacity while reducing power consumption. .

Description

A method of transmitting a wireless communication signal {METHOD FOR TRANSMITTING WIRELESS COMMUNICATION SIGNALS}

The present invention applies LIS (Large Intelligent Surface) technology while utilizing various orbital angular momentum (OAM) modes by applying a Mode Division Multiple Access (MDMA) method based on Orbital Angular Momentum (OAM). By doing so, the present invention relates to a method of transmitting a wireless communication signal capable of improving communication channel capacity while reducing power consumption.

As is well known, the conventional communication system is a method using linear momentum from the viewpoint of electromagnetics, Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), MIMO Like (Multi-Input and Multi-Output) technology, communication is performed through frequency, time, code dimension, and spatial domain.

However, in the case of such an existing communication system, as the number of users and the required transmission capacity increase, the available resources are limited, so the efficiency decreases, and accordingly, it is difficult to find a communication resource of a new dimension became very important.

In accordance with this trend, research on a communication system using orbital angular momentum (OAM) started from optical communication is attracting attention.

Here, angular momentum is a physical quantity conserved in space-time with respect to a rotating material, and research has been conducted to perform communication using it in optical communication. In particular, in the case of orbital angular momentum (OAM), it is expressed in the form of a quantized integer, which is a form in which electromagnetic waves propagate in a spiral, and each is referred to as a mode. .

In addition, research results have been found that transmission capacity can be increased from several to several tens of times depending on the number of modes in optical communication, and research is underway to apply this to an RF (Radio Frequency) band. In the case of multi-mode transmission technology using the orbital angular momentum (OAM) of electromagnetic waves in the RF band, unlike the existing MIMO technology, independent channels can be configured in a Line-of-Sight (LoS) channel environment, and through this, spectrum efficiency ( It is known that spectral efficiency) and transmission capacity can be increased.

This multi-mode generation technology is known to be applicable to short-distance 5G small cells and wireless backhaul in LoS channel environments that require large-capacity transmission in the future, and various technologies are being developed to improve communication performance using such OAM. am.

1. Korea Patent No. 10-1669354 (Registered on October 19, 2016)

The present invention applies a mode division multiple access (MDMA) method based on orbital angular momentum (OAM) to utilize various orbital angular momentum (OAM) modes while applying LIS (Large Intelligent Surface) technology to reduce power consumption while reducing communication channel An object of the present invention is to provide a method for transmitting a wireless communication signal capable of improving capacity.

In addition, the present invention transmits a transmission signal to the LIS device in a mode division multiple access (MDMA) method according to the multiple orbital angular momentum (OAM) mode in the base station, and uses a plurality of reflection elements in the LIS device to provide near-field users and remote users. An object of the present invention is to provide a method of transmitting a wireless communication signal capable of improving a channel capacity by reflecting each of the transmission signals.

The purpose of the embodiments of the present invention is not limited to the above-mentioned purpose, and other objects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. .

According to an embodiment of the present invention, the base station transmits a transmission signal to the LIS (Large Intelligent Surface) device in a Mode Division Multiple Access (MDMA) method according to the Orbital Angular Momentum (OAM) mode. A method of transmitting a wireless communication signal comprising the step of reflecting the transmission signal to a local user and a remote user, respectively, by using a plurality of reflection elements in the LIS device may be provided.

Also, according to an embodiment of the present invention, a method of transmitting a wireless communication signal in which the transmission signal is transmitted or reflected through a Line-of-Sight (LoS) channel may be provided.

In addition, according to an embodiment of the present invention, the LoS channel may be provided with a method of transmitting a wireless communication signal including a Rician fading channel.

In addition, according to an embodiment of the present invention, each channel capacity of the near user and the far user is a transmission signal-to-noise ratio (SNR) for each orbital angular momentum (OAM) mode, the LIS device and the near user and the far user A method of transmitting a wireless communication signal calculated using a two-channel response matrix between the base station and the singular value of a channel matrix from the base station to the LIS device, and a singular value of a channel matrix from the LIS device to the local user and the far user can be provided.

In addition, according to an embodiment of the present invention, a method of transmitting a wireless communication signal in which the capacity of each channel is calculated in consideration of the order of the channel matrix and the reflection angle of the LIS device may be provided.

The present invention applies a mode division multiple access (MDMA) method based on orbital angular momentum (OAM) to utilize various orbital angular momentum (OAM) modes while applying LIS (Large Intelligent Surface) technology, thereby reducing power consumption while reducing the communication channel capacity can be improved.

In addition, the present invention transmits a transmission signal to the LIS device in a mode division multiple access (MDMA) method according to the multiple orbital angular momentum (OAM) mode in the base station, and uses a plurality of reflection elements in the LIS device to provide near-field users and remote users. By reflecting each of the transmitted signals, the channel capacity can be improved.

1 is a flowchart illustrating a process of transmitting a wireless signal according to an embodiment of the present invention;
2 is a diagram illustrating a system to which a method of transmitting a wireless signal according to an embodiment of the present invention is applied;
3 is a diagram for explaining that the channel capacity is improved through the method of transmitting a wireless signal according to an embodiment of the present invention.

Advantages and features of embodiments of the present invention, and methods of achieving them, will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

In describing the embodiments of the present invention, if it is determined that a detailed description of a well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms to be described later are terms defined in consideration of functions in an embodiment of the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

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

1 is a flowchart illustrating a process of transmitting a wireless signal according to an embodiment of the present invention, FIG. 2 is a diagram illustrating a system to which a method for transmitting a wireless signal according to an embodiment of the present invention is applied, and FIG. 3 is this It is a diagram for explaining that the channel capacity is improved through the method of transmitting a wireless signal according to an embodiment of the present invention.

1 to 3, the base station 10 transmits a transmission signal in a Mode Division Multiple Access (MDMA) method according to an Orbital Angular Momentum (OAM) mode to a Large Intelligent Surface (LIS). It can be transmitted to the device 20 (step 110).

Here, if the multiple orbital angular momentum (OAM) mode is described, by mode division multiplexing and transmitting multiple signals in a mode division multiple access (MDMA) method through modes having different helical phase fronts, LoS It is possible to obtain a high transmission rate in the channel, and it can be generated so that its phase changes linearly from 0 to 2πm clockwise along an arc on a plane perpendicular to the propagation direction of the electromagnetic wave. can be said to have

As such, in the multi-orbital angular momentum (OAM) mode, since different mode signals have phases that change at different speeds in space, even when transmitting multiple mode signals overlappingly through the same space using the orthogonal form of this phase It is possible to stably separate the desired signal at the receiving end.

In the case of the multiple orbital angular momentum (OAM) mode as described above, for example, first, by using the reflection characteristics of electromagnetic waves, the signal of the horn feeding unit is reflected from the parabolic reflector having a step difference to generate the orbital angular momentum mode. Second, an orbital angular momentum mode can be generated by forming a step in the dielectric lens to generate a rotation mode. Third, an orbital angular momentum mode can be generated using a uniform circular array antenna consisting of N patches along a circular trajectory. Fourth, an orbital angular momentum mode can be generated through a single-fed elliptical patch antenna that generates a circular polarization by creating an asymmetrical shape called an ellipse in a circular structure. Fifth, an orbital angular momentum mode can be generated by giving a step difference to the sub-reflector instead of the main reflector. Sixth, an orbital angular momentum mode can be generated by using a reflector in which a curved reflector is transformed into a small-volume reflect array method.

On the other hand, LIS was developed to improve the channel capacity, which determines the rate of bits per second allocated to the frequency band according to the channel state, and is provided as an inexpensive passive artificial structure that can digitally manipulate electromagnetic waves. , can be presented as a planar array of nearly passive, low-cost, low-energy-consuming reflective elements with reconfigurable parameters, each of which is known to be capable of inducing a specific phase shift in an incident electromagnetic wave.

In addition, the LIS device 20 may reflect the transmission signal to the near user 30 and the far user 40 by using a plurality of reflective elements, respectively (step 120).

Here, the transmission signal may be transmitted or reflected through a Line-of-Sight (LoS) channel, and may include, for example, a Lician fading channel. Such a Rician fading channel is known as a model of a propagation environment in which LoS exists like a satellite communication system and a direct wave component dominates compared to a reflected wave component.

Briefly describing the system for transmitting the wireless transmission signal as described above, as shown in FIG. 2 , the base station 10, the LIS device 20, and a short-distance user ( 30, CCU: Cell Center User, UE1) and a remote user (40, CEU: Cell Edge User, UE2) in the cell edge (cell edge) can be built a LIS-OAM-MDMA system including the LIS device In (20), a total of M reflective elements are arranged and may be arranged in the center of the cell, and each element may be indicated by m of the LIS device 20 .

Multiple OAM mode (N-1 OAM modes) through this system transmits a wireless transmission signal from the base station 10 to the LIS device 20 using MDMA technology, and the LIS device 20 uses the wireless transmission signal (OAM) By reflecting the wave) to the local user 30 and the far user 40, respectively, the wireless transmission signal transmitted from the base station 10 can be stably transmitted to the local user 30 and the far user 40.

On the other hand, if the channel capacity is improved through the wireless signal transmission method according to the embodiment of the present invention as described above in detail, the base station 10, the LIS device 20, the local user 30, and the remote user In the LIS-OAM-MDMA system including 40, each channel capacity of the near user 30 and the far user 40 is, the transmission signal-to-noise ratio (SNR) for each orbital angular momentum (OAM) mode, and the LIS device (20) and a two-channel response matrix between the local user 30 and the far user 40, the singular value of the channel matrix from the base station 10 to the LIS device 20, and the local user ( 30) and the singular value of the channel matrix up to the remote user 40 may be used to calculate each channel capacity, and the channel capacity may be calculated in consideration of the order of the channel matrix and the reflection angle of the LIS device 20 .

는 채널 위상을 나타낸다.For example, as shown in FIG. 2, in the LIS-OAM-MDMA system, where K, K1, and K2 are from the base station 10 to the LIS device 20 and from the LIS device 20 to the local user 30, respectively. , means the LOS channel from the LIS device 20 to the remote user 40, d1 and d2 are the respective distances from the LIS device 20 to the local user 30 and the far user 40, and d is the base station ( 10) represents the distance from the LIS device 20, θA, θD are the channel angle parameters,

represents the channel phase.

In this LIS-OAM-MDMA system, each achievable channel capacity of the local user 30 and the remote user 40 is Equation 1 (channel capacity of the near user 30) and Equation 2 (the remote user 40) ) of the channel capacity).

는 LIS 장치(20)에 의한 반사 각도를 의미한다.Here, H means a channel between the base station 10 and the LIS device 20, ρ is the transmission SNR (Signal-to-Noise Ration) for each OAM mode, and h1 and h2 are each LIS device 20 and It is a two-channel response matrix between the local user 30 and the far user 40, and μN, q and μF, q are the channel matrix from the LIS device 20 to the local user 30 and to the far user 40 is a singular value, μH, q is a singular value of the channel matrix from the base station 10 to the LIS device 20, Q is the rank of the channel matrix,

denotes a reflection angle by the LIS device 20 .

As described above, if the two-channel response matrix h1 and h2 between the LIS device 20 and the local user 30 and the far user 40 are described, the channel matrix between the base station 10 and the LIS device 20 is as follows. It can be expressed as Equation 3 of

Here, M denotes the total number of uniform circular array (UCA) and OAM modes.

And, the elements of the channel matrix from the base station 10 to the LIS device 20 can be expressed as in Equation 4 below.

Here, k=2π/λ, and λ means a wavelength.

Next, each channel matrix between the base station 10 and the local user 30 and the base station 10 and the far user 40 can be expressed as Equations 5 and 6 below.

In addition, the channel element from the LIS device 20 to the short-distance user 30 can be expressed as in Equation 7 below.

And, the channel element from the LIS device 20 to the remote user 40 can be expressed as in Equation 8 below.

=180°, g₁=g₂=2. K=5, K₁=5 및 K₂=2로 설정될 수 있으며, 도 3에 도시한 바와 같이 기존 LIS 지원 셀룰러 통신보다 훨씬 더 높은 채널 용량을 제공함을 보여준다. 여기에서,

는 LIS 장치(20)의 m 번째 요소에 의해 도입된 위상 편이를 의미한다.On the other hand, when analyzing and comparing the channel capacity of the LIS-OAM-MDMA scheme and the existing LIS-supported cellular communication system according to the embodiment of the present invention, the parameters l ₀ =0, l _N-1 =+1, d=0.25λ , d ₁ =50λ, d ₂ =100λ, λ=0.01, M=64, N=2, θ _A =90°, θ _D =45°,

=180°, g ₁ =g ₂ =2. It can be set to K=5, K ₁ =5 and K ₂ =2, which shows that it provides a much higher channel capacity than the existing LIS-supported cellular communication as shown in FIG. 3 . From here,

denotes the phase shift introduced by the m-th element of the LIS device 20 .

As described above, since multiple channels used in different OAM modes can transmit multiple symbols to the local user 30 and the far user 40 at the same time without interference, compared to the existing LIS-supported cellular communication system, the implementation of the present invention It can be seen that the channel capacity can be improved in the case of the local user 30 and the far user 40 of the LIS-OAM-MDMA scheme according to the example.

Therefore, the present invention applies a mode division multiple access (MDMA) method based on orbital angular momentum (OAM) to utilize various orbital angular momentum (OAM) modes while applying LIS (Large Intelligent Surface) technology, while reducing power consumption It is possible to improve the communication channel capacity.

In addition, the present invention transmits a transmission signal to the LIS device in a mode division multiple access (MDMA) method according to the multiple orbital angular momentum (OAM) mode in the base station, and uses a plurality of reflective elements in the LIS device to provide near-field users and far-field users. By reflecting each of the transmitted signals, the channel capacity can be improved.

In the above description, various embodiments of the present invention have been presented and described, but the present invention is not necessarily limited thereto. It will be readily appreciated that branch substitutions, transformations and alterations are possible.

10: base station
20: LIS device
30: short-distance user
40: remote user

Claims (5)

Transmitting a transmission signal to a LIS (Large Intelligent Surface) device in a Mode Division Multiple Access (MDMA) method according to the Orbital Angular Momentum (OAM) mode at the base station;
In the LIS device, using a plurality of reflective elements to reflect each of the transmission signal to a short-distance user and a long-distance user
including,
The transmission signal is transmitted or reflected through a Line-of-Sight (LoS) channel,
The LoS channel includes a Rician fading channel,
Each channel capacity of the near user and the far user is,
A transmit signal-to-noise ratio (SNR) for each orbital angular momentum (OAM) mode, a two-channel response matrix between the LIS device and the near and far users, and a singular value of a channel matrix from the base station to the LIS device, By calculating using the singular value of the channel matrix from the LIS device to the near user and the far user, the rank of the channel matrix, and the reflection angle of the LIS device,
Multiple channels used in different OAM modes can transmit symbols to local users and far users without interference, so that the LIS-OAM-MDMA method can improve the channel capacity of local and far users. How the signal is transmitted.
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