KR20230088058A - Multi-hop relay wireless communication system and method for minimizing source transmission power - Google Patents

Abstract

The present invention provides a multi-hop relay wireless power transmission system including a source node, a plurality of relay nodes that simultaneously perform beamforming of power and information in a multi-homed manner, and a destination node, wherein the relay node comprises a source A receiving unit for receiving the RF signal of the node; A controller for dividing power and information into a power division ratio (PS ratio) or a time division ratio (TS ratio) for energy harvesting (EH) and information decoding (ID) in the received RF signal; And a transmission unit for sequentially beamforming the power and information divided by the control unit to the next relay node, wherein the control unit uses inverse average inter-node channel gains (IAICG) to perform energy and It is characterized by selecting the next relay node that can be routed through the shortest path having the maximum channel gain and the minimum number of nodes according to rate constraints.

Description

Multi-hop relay wireless communication system and method minimizing source transmission power

The present invention relates to a multi-hop relay-type wireless communication system and method, and more particularly, to a multi-hop relay-type wireless communication system that minimizes source transmission power when performing beepforming for simultaneous transmission of power and information in a multi-hop relay manner, and It's about how.

Recently, as the capacity of transmission data and the high speed of data transmission are progressing to provide multimedia services, research on multiple antenna systems (MIMO (Multiple Input Multiple Output)) that can efficiently use limited frequencies is being actively conducted.

Such a multi-antenna system can transmit data using independent channels for each antenna, thereby increasing transmission reliability and data rate compared to a single-antenna system without additional frequency or transmission power allocation.

A multi-antenna system in a multi-user environment removes interference between users or between antennas using dirty paper coding, which is a nonlinear pre-coding method.

Dirty paper coding is an interference signal cancellation technique in a transmitter that prevents a receiver from being affected by an interference signal when the transmitter knows the interference signal in advance in the presence of an interference signal in addition to a noise signal in a channel. That is, assuming that signal A is a signal to be sent to user A and signal B is to be sent to user B, signal A is first processed from an appropriate relationship with signal B, and a signal like noise (A' ) is created and added to signal B and transmitted through the channel. User B who receives this signal considers both the noise from the channel of the original signal B and the processed signal (A') as noise and decodes it. Then, user A perfectly restores signal A from the processed noise (A'). This is called dirty paper coding.

This DPC technology was developed as a multi-input multi-output (MIMO) multi-antenna utilization technology in a single-hop wireless network such as a cellular mobile phone network.

However, the current wireless network is dominated by single-hop wireless networks such as cellular or WiFi, but multi-hop network configuration is becoming essential for next-generation wireless networks such as 4G, WiBro, and mesh. there is.

A technology in which a wireless communication node simultaneously transmits power and information in such a multi-hop relay type WPCN is referred to as simultaneous wireless information and power transfer (SWIPT). Research and development are underway to implement the WPCN, WPT and SWIPT systems and exploit the potential benefits of these systems.

Recently, the idea of SWIPT has been extended to non-regenerative and regenerative relay systems. In the case of a non-regenerative relay system, each relay transmits the received signal as it is without decoding it. In the case of a regenerative relay system, each relay first decodes the received signal and generates a transmission signal based on the decoded message.

Research on cooperation of non-regenerative and regenerative relay systems is focused on amplify-and-forward (AF) and decode-and-forward (DF) protocols. For AF and DF systems, relay protocols based on time switching (TS) and power splitting (PS) are being specially studied.

Korea Patent Registration No. 10-2209990

An object of the present invention is to derive an optimal power division ratio (PS rate) or time division ratio (TS rate) for minimizing source transmission power.

Another object of the present invention is to provide an algorithm for optimizing a routing path.

In order to achieve the above object, the present invention provides a multi-hop relay wireless power transmission system including a source node, a plurality of relay nodes that simultaneously perform beamforming of power and information in a multi-homed manner, and a destination node, The relay node includes a receiving unit for receiving an RF signal of a source node; A controller for dividing power and information into a power division ratio (PS ratio) or a time division ratio (TS ratio) for energy harvesting (EH) and information decoding (ID) in the received RF signal; And a transmission unit for sequentially beamforming the power and information divided by the control unit to the next relay node, wherein the control unit uses inverse average inter-node channel gains (IAICG) to perform energy and It is characterized by selecting the next relay node that can be routed through the shortest path having the maximum channel gain and the minimum number of nodes according to rate constraints.

Preferably, the control unit may derive the minimum source transmit power through [Relationship 1] below.

[Relationship 1]

(여기서,

는 노이즈 분산,

는 에너지 수확 효율,

는 요구되는 비율 임계값,

을 의미한다.)

(here,

is the noise variance,

is the energy harvesting efficiency,

is the required rate threshold,

means.)

Preferably, the control unit may derive a power division ratio for minimizing source transmission power through [Relationship 2] below.

[Relationship 2]

(여기서,

는 전력분할 비율을 의미한다.)

(here,

means the power split ratio.)

Preferably, the control unit may derive a time division ratio for minimizing source transmission power through an iterative algorithm of [Relationship 3] below.

[Relationship 3]

(여기서,

는 시간분할 비율,

는 비율 임계값,

를 의미한다.)

(here,

is the time division ratio,

is the ratio threshold,

means.)

이고, 상기 에너지 제약 조건은

일 수 있다.(여기서,

는 달성 가능한 비율(rate),

는 최대 소스 전력을 의미한다.)Preferably, in the case of the power division method, the ratio constraint is

, and the energy constraint is

(where,

is the achievable rate,

means the maximum source power.)

이고, 상기 에너지 제약 조건은

일 수 있다.(여기서,

는 달성가능한 비율(rate),

는 최대 소스 전력을 의미한다.)Preferably, in the case of the time division method, the rate constraint is

, and the energy constraint is

(where,

is the achievable rate,

means the maximum source power.)

In addition, the present invention provides a multi-hop relay wireless power transmission method of a transmission system including a source node, a plurality of relay nodes that simultaneously perform beamforming of power and information in a multi-homed manner, and a destination node, the relay A receiving step of receiving an RF signal of a source node in a node; A control step of dividing power and information into a power division ratio (PS ratio) or a time division ratio (TS ratio) for energy harvesting (EH) and information decoding (ID) in the received RF signal; And a transmission step of sequentially beamforming the power and information divided in the control step to the next relay node, wherein the control step uses inverse average inter-node channel gains (IAICG) Another feature is to select the next relay node that can be routed through the shortest path having the maximum channel gain and the minimum number of nodes according to , energy and rate constraints.

According to the present invention, there is an advantage in that source transmission power can be minimized by deriving a power splitting ratio (PS rate) through a closed non-repetitive algorithm.

In addition, the present invention has an advantage of minimizing source transmission power by deriving a time division ratio (TS rate) through an iterative algorithm.

In addition, the present invention has an advantage of optimizing a routing path through a routing algorithm based on the Dijkstra algorithm (DA).

)
도 5는 본 발명의 실시예에 따른 서로 다른 SWIPT 체계에 대한 라우팅 경로를 나타낸다.

도 6은 본 발명의 실시예에 따른 비율 임계값 변화에 대한 최소 전송 전력의 그래프를 나타낸다.
도 7은 본 발명의 실시예에 따른 소스-목적지 거리에 대한 최소 전송 전력의 그래프를 나타낸다.
도 8은 본 발명의 실시예에 따른 채널 추정 오류에 대한 최소 전송 전력의 그래프를 나타낸다.
도 9는 본 발명의 실시예에 따른 안테나의 수에 대한 최소 전송 전력의 그래프를 나타낸다.
도 10은 본 발명의 실시예에 따른 각 노드에서 수확되는 최소 에너지를 나타낸다. 1 shows a configuration diagram of a multi-hop relay wireless communication system according to an embodiment of the present invention.
2 shows a configuration diagram of a relay node according to an embodiment of the present invention.
3 shows a graph of a convergence test result of an iterative algorithm for obtaining a time division ratio according to an embodiment of the present invention.
4 shows routing paths for different SWIPT schemes according to an embodiment of the present invention. (

)
5 shows routing paths for different SWIPT schemes according to an embodiment of the present invention.

6 shows a graph of minimum transmit power versus rate threshold change according to an embodiment of the present invention.
7 shows a graph of minimum transmit power versus source-destination distance according to an embodiment of the present invention.
8 shows a graph of minimum transmit power versus channel estimation error according to an embodiment of the present invention.
9 shows a graph of minimum transmit power versus the number of antennas according to an embodiment of the present invention.
10 shows the minimum energy harvested at each node according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the contents described in the accompanying drawings. However, the present invention is not limited or limited by exemplary embodiments. The same reference numerals in each figure indicate members performing substantially the same function.

The objects and effects of the present invention can be naturally understood or more clearly understood by the following description, and the objects and effects of the present invention are not limited only by the following description. In addition, in describing the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

1 shows a configuration diagram of a multi-hop relay wireless communication system 10 according to an embodiment of the present invention. Referring to FIG. 1 , a multi-hop relay wireless communication system 10 may include a source node 110, a relay node 130, and a destination node 150. The multi-hop relay wireless communication system 10 may perform wireless communication using a power splitting method or a time splitting method.

In the multi-hop relay wireless communication system 10, a source node 110 can communicate with a destination node 150 by routing through k SWIPT multi-hop wireless relay nodes 130 in a wireless network. The multi-hop relay wireless communication system 10 may be composed of a node having a plurality of antennas.

The source node 110 and the destination node 130 may have their own energy sources. The source node 110 may mean a gateway, the Internet, or an external system. Each relay node 130 may be configured to simultaneously beamform information decoding and energy harvesting (EH) from a supercapacitor and a radio signal (RF).

릴레이 노드(120)는 수신부(131), 제어부(133), 및 송신부(135)를 포함할 수 있다. 2 shows a configuration diagram of a relay node 130 according to an embodiment of the present invention. Referring to Figure 2, each

The relay node 120 may include a receiving unit 131 , a control unit 133 , and a transmission unit 135 .

The receiver 131 may receive the RF signal transmitted from the source node 110 . The receiver 131 may combine the received RF signal with noise and transmit it to the control unit 133 . The transmitter 135 may sequentially beamform the power and information divided by the controller 133 to the next relay node 130 .

The receiving unit 131 may receive an RF signal such as [Equation 1] from the previous node.

[Equation 1]

는

안테나의 이전 노드의 빔포밍 행렬이며,

의 전력 제한이 있다.

는 이전 노드로부터 수신한 정보 신호 벡터이고,

는 현재 노드의 안테나 노이즈 벡터이다.

는 이전 노드와 현재 노드 사이의 채널 계수이다. From here,

Is

The beamforming matrix of the previous node of the antenna,

has a power limit.

Is the information signal vector received from the previous node,

is the antenna noise vector of the current node.

is the channel coefficient between the previous node and the current node.

이다.

는 추정된 채널 행렬이고,

는 추정된 채널 에러 행렬이다.

의 각 원소는

로 모델링될 수 있다(

).

를 만족하고,

large-scale 페이딩 계수이다(ij는 연속되는 두 노드를 의미한다). large-scale 페이딩 계수는

로 정의된다.

는 신호 감쇄 계수,

는 거리 손실 지수,

는 경로 손실 지수이다.

의 각 원소는

로 모델링될 수 있다(

). In the case of incomplete channel state information (CSI),

am.

is the estimated channel matrix,

is the estimated channel error matrix.

Each element of

can be modeled as (

).

satisfies,

It is a large-scale fading coefficient (ij means two consecutive nodes). The large-scale fading coefficient is

is defined as

is the signal attenuation coefficient,

is the distance loss exponent,

is the path loss exponent.

Each element of

can be modeled as (

).

In the power division scheme (PS), an RF signal received at node k may be divided into energy harvesting (EH) and information decoding (ID) according to a power division ratio (PS ratio). [Equation 2] is the RF signal part used in energy harvesting, and [Equation 3] is the RF signal part used in information decoding.

[Equation 2]

[Equation 3]

는 노드 k의 전력분할 비율이고,

는 정보 디코딩 회로에 의해 유도되는 추가 노이즈이며,

는 수신 결합 행렬이다. From here,

is the power split ratio of node k,

is the additional noise induced by the information decoding circuit,

is the receive combining matrix.

From [Equation 2], the harvest energy stored in the supercapacitor can be expressed as [Equation 4].

[Equation 4]

(여기에서,

는 k번째 노드에 대한 에너지 수확 장치의 에너지 변환 효율이다.)

(From here,

is the energy conversion efficiency of the energy harvesting device for the kth node.)

From [Equation 3], the ratio achievable at the node can be expressed as [Equation 5].

[Equation 5]

(여기에서,

,

)

(From here,

,

)

의 singular value decomposition(SVD)를 적용하면, 이전 노드 최적의 빔포밍 행렬은

, 현재 노드에서의 수신 결합 매트릭스는

로 나타낼 수 있다(

와

는 단일행렬이다.).

는 음이 아닌 대각행렬을 나타낸다.

는 노드 k-1에 대한 프리코딩 전력 할당으로 구성된 대각행렬을 나타낸다.

는 노드 k-1에 대한 프리코딩 전력 할당으로 구성된 대각행렬을 나타낸다.

는

의 0이 아닌 특이값에 해당하는 활성 채널의 수를 나타낸다. 따라서, 각 릴레이 노드(130)에서 수확된 에너지는 [수학식 6]으로 나타낼 수 있다. 또한, 각 노드에서 달성 가능한 비율은 [수학식 7]로 나타낼 수 있다.

Applying the singular value decomposition (SVD) of , the optimal beamforming matrix for the previous node is

, the receive coupling matrix at the current node is

can be expressed as (

and

is a single matrix).

denotes a non-negative diagonal matrix.

represents a diagonal matrix composed of precoding power allocations for node k-1.

represents a diagonal matrix composed of precoding power allocations for node k-1.

Is

Indicates the number of active channels corresponding to a non-zero singular value of . Therefore, the energy harvested from each relay node 130 can be expressed by [Equation 6]. In addition, the ratio achievable at each node can be expressed by [Equation 7].

[Equation 6]

[Equation 7]

에 대한 최소화 문제는 [수학식 8]과 같이 나타낼 수 있다. source transmission power

The minimization problem for can be expressed as [Equation 8].

[Equation 8]

(여기에서,

는 요구되는 비율 임계값,

,

)

(From here,

is the required rate threshold,

,

)

The difference between time-division and power-division is how energy harvesting occurs. While power division divides the signal power for energy harvesting and information decoding, time division divides the time between energy harvesting and information decoding. Therefore, according to a procedure similar to that proposed for the SWIPT power splitting scheme, the energy harvested at the k-th node can be expressed by [Equation 9]. In addition, the achievable ratio can be expressed by [Equation 10].

[Equation 9]

[Equation 10]

(여기서에,

는 노드 k에서 시간분할 비율을 의미한다.)

(here,

means the time division ratio at node k.)

에 대한 최소화 문제는 [수학식 11]과 같이 나타낼 수 있다. source transmission power

The minimization problem for can be expressed as [Equation 11].

[Equation 11]

(여기에서,

)

(From here,

)

The controller 133 may receive a signal in which the signal received by the receiver 131 and noise are combined. The control unit 133 may harvest power from the transmitted RF signal in order to transmit the received signal to the next relay node 130 . The control unit 133 may decode the information received from the previous relay node 130 using the supercapacitor and then consume the harvested power to retransmit it to the next relay node 130 . The controller 133 may harvest power from the RF signal through a power division ratio or a time division ratio in order to perform beamforming for simultaneous transmission of power and information in a Decoding and Forward (DF) scheme.

The controller 133 may divide power and information from the received RF signal into a power division ratio (PS ratio) or a time division ratio (TS ratio) for energy harvesting (EH) and information decoding (ID).

The control unit 133 may derive the minimum source transmit power through the following [Relationship 1].

[Relationship 1]

(여기서,

는 노이즈 분산,

는 에너지 수확 효율,

는 요구되는 비율 임계값,

을 의미한다.)

(here,

is the noise variance,

is the energy harvesting efficiency,

is the required rate threshold,

means.)

The control unit 133 may derive a power division ratio for minimizing the source transmission power through [Relationship 2] below.

[Relationship 2]

(여기서,

는 전력분할 비율을 의미한다.)

(here,

means the power split ratio.)

The controller 133 derives a time division ratio for minimizing source transmission power through an iterative algorithm of [Relationship 3] below.

[Relationship 3]

(여기서,

는 시간분할 비율,

는 비율 임계값,

를 의미한다.)

(here,

is the time division ratio,

is the ratio threshold,

means.)

에서 변수가 계속 존재하기 때문에 SWIPT TS 기술에 대해 폐쇄형 해를 구할 수 없다. 따라서, 제어부(133)은 반복 알고리즘(Algorithm 1)을 통해 소스 전송 전력을 최소화하기 위한 시간분할 비율을 도출할 수 있다. Optimizing the time division method

Since the variable still exists in , a closed-form solution cannot be obtained for the SWIPT TS technique. Accordingly, the control unit 133 may derive a time division ratio for minimizing source transmission power through an iterative algorithm (Algorithm 1).

에서 최소 소스 전송 전력

과 최적의 시간분할 비율

은 [수학식 14]의 반복 알고리즘을 사용하여 도출할 수 있다. [수학식 14]를 이용하여 최종적으로 도출한 최적의 시간분할 비율

는 [관계식 3]으로 나타낼 수 있다. To solve the problem given in [Equation 11], the given total time

Minimum source transmit power at

and optimal time division ratio

can be derived using the iterative algorithm of [Equation 14]. Optimal time division ratio finally derived using [Equation 14]

can be represented by [Relationship 3].

[Equation 14]

[Table 1] represents an iterative algorithm (Algorithm 1) that derives [Relationship 3] through [Equation 14].

[table 1]

The control unit 133 uses inverse average inter-node channel gains (IAICG) to determine the shortest path having the maximum channel gain and the minimum number of nodes according to energy and rate constraints. You can choose the next relay node that can be routed to. The control unit 133 may use a DA algorithm (Algorithm 2) in which an IAICG weight matrix is used. In the embodiment of the present invention, since the channel gain model is composed of channel effects (distance between nodes, signal fading, and Rayleigh fading), and the reciprocal number decreases as the channel gain increases, the DA algorithm using the IAICG weight matrix is suitable. The control unit 133 may select the shortest path based on the highest channel gain and the minimum number of nodes using the DA to which IAICG is applied.

[table 2] shows the DA algorithm (Algorithm 2) in which the IAICG weight matrix is used.

[table 2]

으로 하고, 에너지 제약 조건을

으로 할 수 있다. 여기서,

는 달성 가능한 비율(rate),

는 최대 소스 전력을 의미한다. 제어부(133)는 비율 제약 조건 및 에너지 제약 조건이 만족되지 않을 때 새로운 경로를 선택할 수 있다. In the case of the power division method, the control unit 133 determines the ratio constraint condition.

, and the energy constraint

can be done with here,

is the achievable rate,

denotes the maximum source power. The controller 133 may select a new path when the rate constraint condition and the energy constraint condition are not satisfied.

와

로 표시된 무선 네트워크 내의 모든 가장자리와 꼭지점으로 구성된 그래프 행렬

를 식별하고 개발할 수 있다. 소스 노드(110) 역할을 하는 현재 또는 가장 최근 노드

는 새로운 행렬

를 갖는

값으로 인스턴스화될 수 있다. 행렬

내에는

및 이전 노드는 정의되지 않는다(

).제어부(133)는 위와 같은 방식으로 이전에 선택한 모든 노드를 다시 선택되지 않게 할 수 있다. The multi-hop relay wireless communication system 10 may use a centralized routing algorithm implemented by the source node 110 . Specifically, the source node 110 is

and

A graph matrix consisting of all edges and vertices within the wireless network denoted by

can be identified and developed. The current or most recent node serving as the source node (110)

is the new matrix

having

Can be instantiated by value. procession

within

and the previous node is undefined (

). The control unit 133 may prevent all previously selected nodes from being selected again in the same manner as above.

를 갖는 첫 번째로 연결될 릴레이 노드(130)를 선택할 수 있다. 제어부(133)는 현재 노드에서 목적지 노드(150)에 도달할 때까지 동일한 프로세스를 반복할 수 있다. Next, the source node 110 has the lowest weight that satisfies the ratio and source node power constraints.

It is possible to select the relay node 130 to be connected first having . The control unit 133 may repeat the same process until reaching the destination node 150 from the current node.

으로 하고, 에너지 제약 조건을

으로 할 수 있다. 여기서,

는 달성가능한 비율(rate),

최대 소스 전력을 의미한다. 이하, 프로세스는 전력분할 방식과 동일하다.In the case of the time division method, the control unit 133 sets a rate constraint

, and the energy constraint

can be done with here,

is the achievable rate,

Indicates the maximum source power. Hereinafter, the process is the same as that of the power division method.

In another embodiment of the present invention, a multi-hop relay wireless communication method may include a receiving step, a controlling step, and a transmitting step.

In the receiving step, the relay node may receive the RF signal of the source node. The receiving step refers to a function performed by the above-described receiving unit 131.

The control step may divide power and information from the received RF signal into a power division ratio (PS ratio) or a time division ratio (TS ratio) for energy harvesting (EH) and information decoding (ID). The control step refers to a function performed by the controller 133 described above.

The control step uses inverse average inter-node channel gains (IAICG) to route to the shortest path with the maximum channel gain and the minimum number of nodes according to the energy and rate constraints. You can select the next relay node available.

The transmission step may sequentially beamform the power and information split in the control step to the next relay node. The transmission step refers to a function performed by the transmission unit 135 described above.

The following describes how to implement centralized and decentralized SWIPT rate protocols.

및 소스 전송 전력 최소화를 사용하여 각 노드에 대한 전력분할 비율을 계산한다. 소스 노드(110)는 계산 후 전력분할 비율, 선택된 릴레이 노드(130)의 인덱스 및 정보 신호를 첫 번째 릴레이 노드(130)로 전송한다. 릴레이 노드 k는 디코딩된 정보를 후속 중계 노드의 인덱스 및 전력분할 비율과 함께 다음 릴레이 노드(130)로 전송한다. First, we look at the SWIPT power splitting scheme in a centralized implementation. In the case of the centralized method, the node node 110 knows all the channel gains for the selected relay node 130 in the network. Accordingly, the source node 110 may calculate a power split ratio for each relay node 130 . Source node 110 according to the antenna structure

and calculate a power split ratio for each node using source transmit power minimization. The source node 110 transmits the calculated power split ratio, the index of the selected relay node 130 and an information signal to the first relay node 130 . The relay node k transmits the decoded information to the next relay node 130 together with the index and power split ratio of the next relay node.

We look at the SWIPT time-slicing scheme in a centralized implementation. To implement the centralized approach through the SWIPT time-slicing ratio-based method, Algorithm 1 must be executed in the source node 110 to discover all time-slicing ratios and source transmit powers. The implementation of Algorithm 1 uses four different arithmetic equations. Thus, calculation involves repeating these arithmetic calculations. For this reason, the time division method requires more computational power than the power division method. However, data transmission at each node is the same for both time division and power division ratios. This is because both technologies transmit actual information signals, SWIPT ratios and indices.

Next, we look at the SWIPT power splitting scheme in a distributed implementation. In the SWIPT power splitting scheme, the source node 110 calculates the power splitting ratio of the first relay node 130 as shown in [Equation 15].

[Equation 15]

,

, 및 모든 릴레이 노드(130) 인덱스를 첫 번째 릴레이 노드(130)로 전송한다. k번째 릴레이 노드(130)는 k+1번째의 릴레이 노드(130)의 전력분할 비율을 [수학식 16]과 같이 계산한다. The source node 110 is an information signal after calculation,

,

, and all relay node 130 indices are transmitted to the first relay node 130. The k-th relay node 130 calculates the power split ratio of the k+1-th relay node 130 as shown in [Equation 16].

[Equation 16]

,

,

번째의 릴레이 노드들의 인덱스를 다음 노드인 k+1번째의 릴레이 노드(130)에 전송한다. The k-th relay node 130, which is the current node, has decoded information,

,

,

The indexes of the th relay nodes are transmitted to the k+1 th relay node 130, which is the next node.

An advantage of a centralized implementation is that the relay node 130 is off-loaded with respect to power split ratio calculations. However, the first few relay nodes 130 have a large amount of data bits to process and transmit according to the power split ratio of subsequent relay nodes 130 that are transmitted. A centralized implementation may affect the DF process if the relay node 130 does not have enough memory.

과

를 계산해야 한다는 것이다. A decentralized implementation means that each node receives fewer data bits for the DF function compared to a centralized implementation. A disadvantage of the decentralized implementation is that the relay node 130 transmits the variable before retransmitting to the next node.

class

is that you have to calculate

Hereinafter, simulation results of the present invention will be described.

3 shows a graph of a convergence test result of an iterative algorithm for obtaining a time division ratio according to an embodiment of the present invention. Referring to FIG. 3 , it can be seen that the iterative algorithm (Algorithm 1) begins to converge after two or more iterations.

)4 shows routing paths for different SWIPT schemes according to an embodiment of the present invention. (

)

)5 shows routing paths for different SWIPT schemes according to an embodiment of the present invention. (

)

=30dBm인 Algorithm 2를 통해 수행된다. 최적의 전력분할 비율 방식(

), 고정된 전력분할 비율 방식(

), 최적의 시간분할 비율 방식(

), 고정된 전력분할 비율 방식(

), 최적의 시간분할 비율 방식(

), 고정된 시간분할 비율 방식(

) 각각을 사용하여 소스 노드(110)와 목적지 노드(150) 간의 E2E 통신에 필요한 최소 소스 전력을 탐색한다. 시뮬레이션 토폴로지는 50개의 노드가 차원이 있는 정사각형에 분산된 것이다(

. 여기서,

).Referring to FIGS. 4 and 5 , various routing paths for different DF-SWIPT schemes can be seen. Routing is the maximum available source power

= 30 dBm is performed through Algorithm 2. Optimal power split ratio method (

), fixed power split ratio method (

), the optimal time division ratio method (

), fixed power split ratio method (

), the optimal time division ratio method (

), fixed time division ratio method (

) is used to search for minimum source power required for E2E communication between the source node 110 and the destination node 150. The simulated topology is 50 nodes distributed in a dimensional square (

. here,

).

4 and 5 show that the same or different routing paths can be selected for information transmission based on energy harvesting scheme, antenna configuration and channel gain. 4 and 5 also show that the minimum source power required to support communication increases as the total area increases. Therefore, it can be seen that an attempt to apply both SWIPT-based energy harvesting and routing functions is very helpful in improving performance. As can be seen through FIGS. 4 and 5 , the present invention not only selects the nearest relay node but also uses the least amount of energy during transmission.

6 shows a graph of minimum transmit power versus rate threshold change according to an embodiment of the present invention. Referring to FIG. 6 , it can be seen that the required minimum amount of source power increases as the SNR threshold increases. It can be seen that the two different MIMO configurations with antenna numbers 2 and 5 completely outperform the SISO configuration. It can be seen that MIMO with L = 2 and MIMO with L = 5 reduce energy demand by 100 dBm and 150 dBm, respectively.

를 필요로 하는 것을 알 수 있다. 또한, 최적의 방식은 최소

측면에서 고정 비율 방식보다 성능이 뛰어남을 알 수 있다. In particular, focusing on two different MIMO setups, it can be seen that the transmit power demand increases by about 50 dBm in the same scheme for different antenna configurations. This can be confirmed by the reasoning of the closed-end solution for the minimum required source transmit power. In addition, compared to the time division scheme, the power division scheme requires fewer

It can be seen that it requires Also, the optimal method is

From the side, it can be seen that the performance is superior to the fixed ratio method.

는 노드간 거리가 10m에서 30m로 늘어남에 따라 증가함을 알 수 있다. MIMO 모델은 L=1과 L=2 사이에서 약 80dBm, L=1과 L=5 사이에서 약 130dBm의 하락으로 벤치마크 SISO 모델을 능가함을 알 수 있다. 또한, 최적의 방식은 고정 비율 방식보다 성능이 우수함을 알 수 있다. 예를 들면, 최적 전력분할 방식은 L=5로 설정된 고정 비율 방식으로 이동할 때 전력 수요가 약 20dBm이 증가한다. 안테나는 5에서 2로 감소할 때, 모든 방식에 대한 소스-목적지 통신을 지원하는데 필요한 최소

가 증가함을 알 수 있다. 7 shows a graph of minimum transmit power versus source-destination distance according to an embodiment of the present invention. Referring to Figure 7, the minimum required

It can be seen that increases as the distance between nodes increases from 10 m to 30 m. It can be seen that the MIMO model outperforms the benchmark SISO model with a drop of about 80dBm between L=1 and L=2 and about 130dBm between L=1 and L=5. In addition, it can be seen that the optimal method has better performance than the fixed ratio method. For example, the power demand increases by about 20 dBm when the optimal power splitting scheme moves to a fixed ratio scheme with L=5. When antennas are reduced from 5 to 2, the minimum required to support source-destination communication for all modes

It can be seen that increases.

8 shows a graph of minimum transmit power versus channel estimation error according to an embodiment of the present invention. Referring to FIG. 8 , it can be confirmed that the optimized MIMO routing scheme is more advantageous than the benchmark SISO system. That is, it can be seen that the energy required for transmission increases as the channel estimation error increases.

9 shows a graph of minimum transmit power versus the number of antennas according to an embodiment of the present invention. Referring to FIG. 9, it can be seen that the energy required for transmission decreases as the number of antennas of each node increases. It can be seen that the minimum required source transmission energy increases as the channel estimation error increases from 0 to 0.3. This means that an increase in channel estimation error causes a larger loss. It can be seen that the optimal power division scheme outperforms the optimal time division scheme.

10 shows the minimum energy harvested at each node according to an embodiment of the present invention. Referring to FIG. 10 , it can be seen that node 1 harvested more energy than node 2 when there are two relay nodes 130 . The power splitting method and the time splitting method have the same node energy harvest. Node 1 is 70dBm to 65dBm, node 2 is 85dBm to 65dBm. However, it can be seen that the overall cumulative effect is greater in the power division method than in the time division method.

Although the present invention has been described in detail through representative embodiments, those skilled in the art will understand that various modifications are possible to the above-described embodiments without departing from the scope of the present invention. will be. Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, and should be defined by all changes or modifications derived from the claims and equivalent concepts as well as the claims to be described later.

10: Multi-hop relay wireless communication system
110: source node
130: relay node
131: receiver
133: control unit
135: transmission unit
150: destination node

Claims (7)

A multi-hop relay wireless power transmission system including a source node, a plurality of relay nodes that simultaneously perform beamforming of power and information in a multi-homed manner, and a destination node,
The relay node,
A receiving unit for receiving the RF signal of the source node;
A controller for dividing power and information into a power division ratio (PS ratio) or a time division ratio (TS ratio) for energy harvesting (EH) and information decoding (ID) in the received RF signal; and
A transmission unit for sequentially beamforming the power and information divided by the control unit to the next relay node;
The control unit routes to the shortest path having the maximum channel gain and the minimum number of nodes according to energy and rate constraints using inverse average inter-node channel gains (IAICG). A multi-hop relay wireless communication system, characterized in that for selecting the next possible relay node.
According to claim 1,
The control unit,
A multi-hop relay-type wireless communication system, characterized in that the minimum source transmit power is derived through [Relationship 1] below.
[Relationship 1]

(here,

is the noise variance,

is the energy harvesting efficiency,

is the required rate threshold,

means.)
According to claim 2,
The control unit,
A multi-hop relay-type wireless communication system, characterized in that a power division ratio for minimizing source transmission power is derived through [Relationship 2] below.
[Relationship 2]

(here,

means the power split ratio.)
According to claim 2,
The control unit,
A multi-hop relay-type wireless communication system, characterized in that a time division ratio for minimizing source transmission power is derived through an iterative algorithm of [Relationship 3] below.
[Relationship 3]

(here,

is the time division ratio,

is the ratio threshold,

means.)
According to claim 1,
In the case of the power splitting method, the ratio constraint is

, and the energy constraint is

A multi-hop relay wireless communication system, characterized in that. (here,

is the achievable rate,

means the maximum source power.)
According to claim 1,
In the case of the time division method, the rate constraint is

, and the energy constraint is

A multi-hop relay wireless communication system, characterized in that. (here,

is the achievable rate,

means the maximum source power.)
In a wireless power transmission method of a multi-hop relay method of a transmission system including a source node, a plurality of relay nodes that simultaneously perform beamforming of power and information in a multi-home method, and a destination node,
A receiving step of receiving an RF signal of a source node in the relay node; A control step of dividing power and information into a power division ratio (PS ratio) or a time division ratio (TS ratio) for energy harvesting (EH) and information decoding (ID) in the received RF signal; And a transmission step of sequentially beamforming the power and information divided in the control step to the next relay node,
The control step uses inverse average inter-node channel gains (IAICG) to determine the shortest path having the maximum channel gain and the minimum number of nodes according to energy and rate constraints. A multi-hop relay wireless communication method characterized by selecting the next routable relay node.

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