KR20120058349A - Apparatus for sharing resource and method using thereof - Google Patents

Apparatus for sharing resource and method using thereof Download PDF

Info

Publication number
KR20120058349A
KR20120058349A KR1020100120084A KR20100120084A KR20120058349A KR 20120058349 A KR20120058349 A KR 20120058349A KR 1020100120084 A KR1020100120084 A KR 1020100120084A KR 20100120084 A KR20100120084 A KR 20100120084A KR 20120058349 A KR20120058349 A KR 20120058349A
Authority
KR
South Korea
Prior art keywords
signal
sub
source node
node
main
Prior art date
Application number
KR1020100120084A
Other languages
Korean (ko)
Other versions
KR101236976B1 (en
Inventor
공형윤
충 두이 창
Original Assignee
울산대학교 산학협력단
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 울산대학교 산학협력단 filed Critical 울산대학교 산학협력단
Priority to KR20100120084A priority Critical patent/KR101236976B1/en
Priority to PCT/KR2011/008929 priority patent/WO2012074239A2/en
Publication of KR20120058349A publication Critical patent/KR20120058349A/en
Application granted granted Critical
Publication of KR101236976B1 publication Critical patent/KR101236976B1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/16—Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/022—Site diversity; Macro-diversity
    • H04B7/024—Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems

Landscapes

  • Engineering & Computer Science (AREA)
  • Quality & Reliability (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Radio Relay Systems (AREA)

Abstract

PURPOSE: A resource sharing apparatus and resource sharing method thereof are provided to enable a sub source node to transmit sub source node signal by transmitting transmission signals of a main source node to a main destination node through various routes. CONSTITUTION: A main destination node processes a first signal transmitted through a first time slot and a combination signal transmitted through a second time slot(S330). The main destination node corresponds to a source node. A sub destination node receives the combination signal. The sub destination node corresponds to the sub source node. The sub destination node processes the second signals(S335).

Description

Apparatus for sharing resource and method using YOO}

The present invention relates to a resource sharing apparatus and a resource sharing method, and more particularly, to a resource sharing apparatus for transmitting a signal by sharing a frequency resource and a resource sharing method accordingly.

Due to the rapid increase in the number of wireless devices, the lack of usable frequencies has become an important issue. In order to solve this problem, one of the proposed technologies may be a radio recognition technology, a cooperative communication technology and the like.

The wireless recognition technology refers to a technology for improving frequency efficiency by sharing an idle frequency portion of an existing primary user without infringing the authority of an existing primary user based on a dynamic frequency resource management concept.

In addition, cooperative relaying technology transmits signals through multiple paths formed by two or more communication nodes having equivalent functions, and signals are relayed through the at least one path to the destination, and these multiple paths It means a communication scheme for estimating transmission information by combining or selecting the signals received from them.

In particular, such cooperative communication technology can secure a plurality of communication paths by relaying signals from a plurality of communication nodes to a destination, but the plurality of relay furnaces only relay a signal to a destination, and a signal they want to transmit is transmitted. There has been a problem in frequency utilization efficiency.

In order to solve the above problems of the present invention, an object of the present invention is that the main source node transmits a signal to the main destination node, and transmits itself to the transmission signal of the main source node received by the sub source node. A resource sharing apparatus for combining and transmitting a desired signal and a resource sharing method using the same are provided.

According to an embodiment of the present invention, a resource sharing method in a cooperative communication system including a plurality of nodes may include a main signal receiving a first signal through a first time slot of a preset frequency band. Broadcasting, the sub-source node receives the signal and combines it with a second signal to be transmitted by the sub-source node, and broadcasts the combined combined signal through a second time slot of the preset frequency band; and The main destination node corresponding to the main source node receives and processes the first signal transmitted through the first time slot and the combined signal transmitted through the second time slot, and the sub corresponding to the sub source node. A destination node receiving the combined signal and processing the second signal.

Here, the sub source node and the sub destination node may be formed of a plurality of pairs corresponding to each other.

Here, the plurality of sub source nodes sequentially transmits a signal to be transmitted and a combined signal combining the first signal by using time slots after the first time slot, and the plurality of sub source nodes. The plurality of sub-destination nodes corresponding to may receive the combined signal transmitted through each time slot and process the signal of the corresponding sub-source node.

Meanwhile, the combined signal may linearly combine the first signal and the second signal by applying a power weight corresponding to each of the first signal and the second signal, as shown in the following equation.

Figure pat00001

Here, x p is the first signal transmitted from the main source node, x s is the second signal to be transmitted from the sub source node, P is the transmission power of the sub node, α and 1-α are the division of the transmission power. The coefficient, x c, is preferably a combined signal in which the first signal and the second signal are combined.

On the other hand, according to another embodiment of the present invention, the resource sharing method of the sub-source node for relaying a signal transmitted from the main source node is the sub-source node from the main source node through a first time slot of a preset frequency band Receiving the broadcasted first signal, the sub-source node applies the power weight corresponding to each of the received first signal and the second signal to be transmitted by the sub-source node to apply the first signal and the second signal Linearly combining and the sub-source node broadcasting the combined combined signal through a second time slot of a predetermined frequency band.

Here, in the combining step, the first signal and the second signal may be combined using the following equation.

Figure pat00002

Here, x p is the first signal transmitted from the main source node, x s is the second signal to be transmitted from the sub source node, P is the transmission power of the sub node, α and 1-α are the division of the transmission power. The coefficient, x c, is preferably a combined signal in which the first signal and the second signal are combined.

On the other hand, according to another embodiment of the present invention, the resource sharing method of the main destination node for receiving a signal transmitted by the main source node through a plurality of sub-source nodes, the first destination node in the first frequency band of a predetermined frequency band; Receiving a first signal broadcast from a main source node through a time slot; and receiving and processing a combined signal transmitted by the sub source node through a second time slot of the preset frequency band by the main destination node. And the combined signal is a combined signal that the sub source node receives the first signal and combines it with a second signal to be transmitted by the sub source node.

Here, the combined signal may be calculated using the following equation.

Figure pat00003

Here, x p is the first signal transmitted from the main source node, x s is the second signal to be transmitted from the sub source node, P is the transmission power of the sub node, α and 1-α are the division of the transmission power. The coefficient, x c, is preferably a combined signal in which the first signal and the second signal are combined.

Meanwhile, according to another embodiment of the present disclosure, a node device may include an interface unit configured to receive a first signal broadcast by a main source node through a first time slot of a preset frequency band, a signal to be transmitted, and the first signal. And a controller configured to combine the signals to generate a combined signal and to control the interface unit to broadcast the combined signal through a second time slot of the frequency band.

According to various embodiments of the present disclosure, an apparatus for sharing a resource and a method for sharing resources according thereto may generate a combined signal by combining a signal to be transmitted by a sub source node with a transmitted signal of a received main source node, and may combine the combined signal with each other. Can broadcast in other time slots. Accordingly, since the transmission signal of the main source node is transmitted to the main destination node along a plurality of paths, various diversity gains can be obtained, and the sub source node can also transmit its own signal to the sub destination node.

1 is a block diagram of a cooperative communication system according to an embodiment of the present invention;
2 is a block diagram of a sub source node forming a cooperative communication system according to an embodiment of the present invention;
3 is a flowchart illustrating a resource sharing method of a cooperative communication system according to an embodiment of the present invention;
4 is a flowchart illustrating a resource sharing method of a sub source node according to an embodiment of the present invention;
5 is a flowchart illustrating a resource sharing method of a main destination node according to an embodiment of the present invention;

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

1 is a block diagram illustrating a cooperative communication system according to an embodiment of the present invention.

Referring to FIG. 1, the cooperative communication system 100 includes a main source node 110, a plurality of sub source nodes 120-1, 120-2,..., 120-n, and a plurality of sub destination nodes 125. -1, 125-2, ..., 125-n) and main destination node 130. In Figure 1, the main source node 110 PR, a plurality of sub-source node (120-1, 120-2, ..., 120 -n) is ST 1, ST 2, ..., respectively, ST N, The plurality of sub-destination nodes 125-1, 125-2,..., And 125-n are SR 1 , SR 2 ,..., SR N , and the main destination node 130 is shown as a PR for convenience.

The cooperative communication system 100 transmits a constant signal from the main source node 110 to the main destination node 130, and also includes a plurality of sub source nodes 120-1, 120-2, ..., 120-. n) may transmit its signal to each of the plurality of sub-destination nodes 125-1, 125-2,..., 125-n while assisting the signal transmission of the main source node 110.

In addition, in the communication system 100, when the main source node 110 and the plurality of sub source nodes 120-1, 120-2, ..., 120-n each want to transmit signals, In the frequency band, different signals can be transmitted using different time slots. The time slot setting will be described later in more detail.

The main source node 110 may broadcast its signal during a predetermined time slot of a preset frequency band. At this time, the main source node 110 may encode its signal and broadcast using a constant transmission power (P). Here, since the signal of the main source node 110 is broadcast, not only the main source node 130 corresponding to the main source node, but also a plurality of sub source nodes 120-1, 120-2, ..., 120-. n) and the plurality of sub-destination nodes 125-1, 125-2,..., 125-n may also receive this.

Here, the predetermined time slot value may be automatically set according to the control of the controller (not shown) received from the user through an input unit (not shown) or based on previously stored time slot information.

The plurality of sub source nodes 120-1, 120-2, ..., 120-n and the plurality of sub destination nodes 125-1, 125-2, ..., 125-n are main source nodes ( The signal broadcast by the 110 may be received, and the received signal of the main source node 110 may be decoded to detect a transmission signal of the main source node 110.

Here, each node decodes a signal such as a maximum ratio ratio combining (MRC) technique, an equal gain combining (EGC) technique, an orthogonality restoring combining (ORC) technique, a minimum mean square error combining (MMCEC) technique, and a linear combining technique (LC). A variety of techniques, such as the following techniques, SC (Selection Combining) technique, etc. may be used.

The plurality of sub source nodes 120-1, 120-2,..., 120-n may broadcast a combined signal during time slots assigned to each sub source node. Here, the combined signal is a signal obtained by combining the signals to be transmitted by each of the sub source nodes to the signal of the received main source node 110, it can be expressed as follows.

Figure pat00004

Here, x p is a signal broadcast by the main source node, x s is a signal to be transmitted from each of the sub source nodes, P is the transmission power of the sub source node, α and 1-α are the partition coefficient of the transmission power, x c is a combined signal in which a signal of a main source node and a signal to be transmitted by a sub source node are combined.

In addition, the combined signal combined with each of the sub source nodes 120-1, 120-2, ..., 120-n may be broadcast in different time slots for each sub source node, and the broadcast signal is the main destination. Node 130 and sub-destination nodes 125-1, 125-2, ..., 125-n.

Meanwhile, the main destination node 130 may detect signals of the main source node 110 by synthesizing the signals of the main source node 110 received through a plurality of paths. Here, the plurality of paths are paths in which the main source node 110 directly transmits a signal to the main destination node 130 in its time slot, and the plurality of sub source nodes 120-1, 120-2, ..., 120-n may refer to a path for combining and transmitting its own signal to the main source node 110 signal in different time slots.

Here, when the main destination node 130 decodes the signals of the main source node 110 by combining, the LC technique may be used to obtain various diversity gains. That is, since the signals of the main source node 110 received through a plurality of paths are linearly combined and decoded, a higher diversity diversity gain can be obtained, and a mathematical proof thereof will be described later.

Meanwhile, the sub-destination nodes 125-1, 125-2, ..., 125-n are broadcasted by the corresponding sub-source nodes 120-1, 120-2, ..., 120-n. By receiving the signal, each sub source node signal can be detected. Specifically, the detection is performed by using the combined signal of the main source node and the sub source node received in different time slots, and a detailed description thereof will be described later.

Meanwhile, the main destination node 130 and the sub destination nodes 125-1, 125-2,..., 125-n are the main source node 110 and the sub source nodes 120-1, 120-2,. 120-n) When receiving and decoding a signal, if the decoding fails, the signal can be re-received by transmitting a control signal to retransmit the signal to the transmitting node.

The combined signal broadcasted by each of the sub source nodes 120-1, 120-2, ..., 120-n is broadcast in a different time slot, and also the sub destination nodes 125-1, 125-2. , ..., 125-n) may be configured by using the signals of the main source node 110 and the sub-source nodes 120-1, 120-2, ..., 120-n respectively received in different time slots. Can detect a sub source node signal. Hereinafter, for example, different time slots will be described in detail.

As an example, assume that there are two pairs of sub node systems (two sub source nodes and two corresponding sub destination nodes) between the main source node and the main destination node. At this time, the signal that the main source node wants to transmit to the main destination node is xp, and the signal that the first sub-source node wants to transmit to the first sub-destination node is xs1 and the second sub-source node goes to the second sub-destination node. Signals to be transmitted are referred to below as xs2, respectively.

Here, the number of sub-node systems is only one example for convenience of description, and the technical idea of the present invention may be implemented by more or fewer sub-node systems.

First, if the main source node broadcasts xp, the main destination node and the two sub source nodes and the two sub destination nodes may receive xp. At this time, broadcast of the main source node and reception of other nodes are performed in a first time slot of a given frequency band.

Upon receiving xp, the first sub-source node generates a combined signal by combining xs1, which is a signal to be transmitted, with xp. This operation is performed by the power weight as in Equation 1 in the first time slot, but for convenience, the combined signal will be referred to as xp + xs1. Thereafter, the first sub source node may broadcast the combined signal xp + xs1 in a second time slot indicating a time interval subsequent to the first time slot.

The xp + xs1 broadcast by the first sub source node may be received by the main destination node and the first sub destination node. In this case, the first sub-destination node may detect xs1, which is a signal transmitted by the first sub-source node, using xp received in the first time slot and xp + xs1 received in the second time slot. This process can be expressed as an equation below.

Figure pat00005

Here, y PR1 represents a signal received by the main destination node from the signal broadcast by the main source node in the first time slot, P is the transmit power of the main source node, h PT , PR are the main source node and the main destination. The fading coefficient between nodes, x p is the transmission signal of the main source node, n PT , PR is the additive white Gaussian noise (AWGN) between the main source node and the main destination node. .

Figure pat00006

Here, y SR1 represents a signal received from the first sub-destination node by a signal broadcast by the main source node in the first time slot, P is a transmit power of the main source node, h PT , and SR represent a main source node. A fading coefficient between sub destination nodes, x p is a transmission signal of a main source node, and n PT and SR are AWGN between a main source node and a first sub destination node.

In a second time slot subsequent to the first time slot, the first sub source node may broadcast a signal that it intends to transmit to the transmission signal of the main source node (see Equation 1 described above), This may be received by the main destination node and the first sub destination node.

Figure pat00007

Figure pat00008

Figure pat00009

Here, y PR2 is a signal received at the main destination node in the second time slot, P is the transmit power of the main source node, h ST , PR and n ST , and PR is fading between the first sub source node and the main destination node. Coefficients and AWGN are shown respectively.

In this case, the signal received by the sub-destination node in the second time slot may be represented as follows.

Figure pat00010

Figure pat00011

Figure pat00012

Here, y SR2 is a signal received by the sub-destination node in the second time slot, P is the transmit power of the main source node, h ST , SR and n ST , and SR is the fading coefficient between the sub-source node and the sub-destination node). And AWGN, respectively.

In conclusion, the first sub-destination node removes the received signal y SR1 in Equation 3 from the received signal y SR2 in Equation 5, so that the first sub-source signal is to be transmitted in the second time slot. The signal can be determined.

Meanwhile, the second sub source node may broadcast a combined signal in a third time slot subsequent to the second time slot. Specifically, xp is decoded by applying the SC scheme to xp received in the first time slot and xp + xs1 received in the second time slot, and xs2, which is a signal to be transmitted to the decoded xp, is combined and combined signal. You can create xp + xs2. Here, the combined signal xp + xs2 is shown for convenience and is combined by the power weight by using Equation 1 described above. Here, the SC technique may mean a technique for selecting and decoding a received signal that is optimal among the received signals, which will be described later.

The combined signal xp + xs2 thus generated is broadcast in the third time slot, and the second sub-destination node and the main destination node may receive the combined signal xp + xs2.

The second sub-destination node receives the main source node signal received in the first time slot and the third chime slot received in the first time slot, as described above (the method of detecting the first sub-source node signal by the first sub-destination node). A signal of the second sub source node may be detected using the combined signal of the two sub source nodes.

Meanwhile, the main destination node may detect a signal of the main source node by using signals received through a plurality of paths. Specifically, xp, which is a signal directly received from the main source node through the first time slot, and xp + xs1, which is a signal received from the first sub source node through the second time slot, and the second sub through the third time slot. By combining xp + xs2 which is a signal received from the source node, xp can be detected. In this case, since xp can be decoded by the LC technique, the signal of the main sword node can be transmitted to the main destination node with various diversity gains.

As such, when all the source nodes have finished transmitting their signals, in the fourth time slot subsequent to the third time slot, the main source node broadcasts its signal xp again, and the above-described process is repeated to transmit the signal. do.

Although the present embodiment is limited to two sub source nodes and two sub destination nodes, this is merely for convenience of description and the number of sub source nodes and corresponding sub destination nodes may be increased for more diversity. have. In this case, the signal received by each sub-destination node may be expressed in the form of Equation 3 and Equation 5 by changing only fading coefficients and AWGN values between main source nodes and corresponding sub-source nodes.

Accordingly, in the cooperative communication system 100 according to an embodiment of the present invention, the main destination node 130 not only receives a signal directly transmitted by the main source node 110, but also each sub source node 120. -1, 120-2, ..., 120-n) receives and decodes a signal transmitted by combining the signal with the signal of the source node to its signal, and thus receives the signal of the main source node 110 through various paths. The diversity gain can be improved. In addition, since each sub source node 120-1, 120-2, ..., 120-n combines and broadcasts its own signal to the signal of the main source node 110, the corresponding sub destination node ( 125-1, 125-2, ..., 125-n) each can transmit its own signal.

2 is a block diagram of a sub source node according to an embodiment of the present invention.

Referring to FIG. 2, the sub source node 200 combines and broadcasts a signal to be transmitted to a signal of a main source node, which may include an interface unit 210 and a controller 210. have. Although FIG. 2 illustrates a block diagram of one sub source node 200, a plurality of sub source nodes may have the same configuration.

The interface unit 210 receives a signal broadcast by the main source node 110. That is, the main source node 110 may receive a transmission signal of the main source node broadcast in the first time slot.

The controller 220 combines a signal to be transmitted by the sub source node 200 with a signal received by the interface unit 210. Specifically, the combined signal may be generated by decoding the transmission signal of the main source node received in the first time slot and combining the signal to be transmitted thereto.

As described above, the plurality of sub-source nodes generate different combined signals in different time slots, which have been described in detail, and thus will be omitted below.

In addition, the controller 220 may control the interface unit 210 to broadcast the combined signal in a time slot after the first time slot. In this case, when a plurality of sub source nodes according to an embodiment of the present invention are provided, each sub source node may transmit a combined signal in different time slots. Specifically, if N sub source nodes are provided, the first sub source node broadcasts the combined signal in the second time slot, and the second sub source node broadcasts the combined signal in the third time slot. Accordingly, the Nth sub-source node broadcasts the combined signal in the N + 1th time slot.

In addition, the controller 220 may control the interface unit 210 to transmit a retransmission command to the node that has transmitted the signal.

3 is a flowchart illustrating a resource sharing method of a cooperative communication system according to an embodiment of the present invention.

First, the main source node broadcasts its signal in a first time slot of a preset frequency band (S310).

Thereafter, the broadcast signal may be received at a plurality of sub source nodes, a plurality of sub destination nodes, and a main destination node, and the plurality of sub source nodes decodes it to detect a signal of the main source node.

Thereafter, each of the sub source nodes combines and broadcasts a signal to be transmitted to the signal of the main source node in different time slots (S320). If there are N sub-source nodes, in a second time slot subsequent to the first time slot, the first sub source node combines and broadcasts its signal to the signal of the main source node, and in the third time slot, broadcasts the second. The sub source node combines and broadcasts its signal to the signal of the main source node. In this way, in the N + 1th time slot, the Nth sub-source node broadcasts by combining its signal with the main source node signal.

Different combined signals broadcast by each sub source node in different time slots may be received at the corresponding sub destination node and the main destination node.

The main destination node may detect the signal of the main source node using the signal of the main source node directly received from the main source node in the first time slot and the combined signal received from each of the sub source nodes in different time slots ( S330). Accordingly, since the main source node signal is received and detected through a plurality of paths, various diversity gains can be obtained.

In addition, the sub-destination node may receive a signal of the sub-source node using a signal broadcast by the corresponding sub-source node in each time slot and a signal broadcast by the main source node in the first time slot. Specifically, in the second time slot, the first sub source node combines its signal with the main source node signal and broadcasts the combined signal, and in the third time slot, the second sub source node sends its own signal to the main source node signal. Combine signals and broadcast combined signals. Accordingly, in the second time slot, the first sub-destination node uses the main source node signal received in the first time slot and the signal of the first sub source node received in the second time slot, and thus the signal of the first source node. Can be detected, and a detailed method has been described in Equations 3 and 5, and will be omitted here. Similarly, in the third time slot, the second sub destination node can detect the signal of the second sub source node.

Although in the above-described embodiments, the number of sub-source nodes and sub-destination nodes is limited to two, respectively, these numbers can be extended, and for N sub-source nodes, the N-th sub-source node is the N + 1 time. It will broadcast the combined signal in the slot.

As described above, in the method of sharing resources in the cooperative communication system according to an exemplary embodiment of the present invention, the sub-source node combines its own signal with the signal of the main source node and broadcasts it in different time slots. It can be transmitted with a diversity gain, and the sub source node can transmit its signal to the sub destination node.

 4 is a flowchart illustrating a resource sharing method of a sub source node according to an embodiment of the present invention.

The sub source node receives a signal broadcast by the main source node during the first time slot (S410).

Thereafter, the sub-source node generates a combined signal by combining the signal to be transmitted with the signal of the received main source node (S420). In this case, since the method of generating the combined signal has been described above, it is omitted here.

The sub source node broadcasts the combined signal during the second time slot (S420). Although described in the above example as the second time slot, when the sub-source node is extended to a plurality, it is possible to transmit each combined signal in a plurality of different time slots.

5 is a flowchart illustrating a resource sharing method of a main destination node according to an embodiment of the present invention.

First, a signal broadcasted through a main source node in a first time slot is received (S510).

If there are a plurality of sub source nodes, the combined signal broadcasted by the first sub source node is received in the second time slot, and similarly, the combined signal of the second sub source node is received in the third time slot, and Nth is received. In the +1 time slot, the combined signal of the Nth sub-source node is received (S520). By using the various signals thus received, the signal of the main source node is detected. In this case, the LC technique may be applied to improve the diversity gain.

Hereinafter, the operation of the cooperative communication system according to an embodiment of the present invention will be analyzed in terms of outage probablity and diversity gain.

To this end, first, a communication environment of a cooperative communication system according to an embodiment of the present invention will be described. For convenience of description, the main source node is represented by PT, the main destination node is represented by RP, and the sub source node and the sub destination node are assumed to be N pairs, and the sub source nodes are ST 1 to ST n and the sub destination node is SR. It represents with 1 to SR n . The channel between each node is assumed to be Rayleigh flat fading. In addition, each node has a single half duplex radio and a single antenna, and because of the half duplex, each node can transmit a signal on a separate channel. In addition, a time division channel assignment is occupied that includes time slots of N + 1 to recognize orthogonal channels.

 When the signal is transmitted at the node i, the signal received at the node j may be expressed as in the following equation.

Figure pat00013

Here, in the node j AWGN noise n j has a variance N 0, h i, j denotes a fading coefficient between node i and node j, x i is the transmit signal at node i. P is also assumed to be the transmit power, which is the same at all nodes.

From Equation 6, the instantaneous signal to noise ratio (SNR) can be determined as follows.

Figure pat00014

here,

Figure pat00015
Means the average SNR.

In Equation 7,

Figure pat00016
Is

parameter

Figure pat00017
Is an exponential distribution with. Considering the path loss, the distribution of channel coefficients between node i and node j can be expressed as a function of distance between nodes,
Figure pat00018
Can be expressed as follows.

Figure pat00019

Here, β is a path loss exponent varying from 2 to 6, and d i , j is the distance between node i and node j.

Hereinafter, theoretically calculate the power failure probability of the cooperative communication system according to an embodiment of the present invention. As described above, it is assumed that the relay node and the destination node of the relay node are N pairs (ST j -SR j (1 <j <N)).

First, it is assumed that a set of relay nodes ST j ((1 <j <N)) that successfully decodes a signal received from a source node is D j . D j is a random match, and the number n of nodes of the set D j may be a random variable having a range of 0 <n <j−1. Further, D j = {ST k1 , ST k2 ,... , ST kn }, where 1 ≦ k 1 <k 2 <. <k n ≤ j-1. In addition, a set of relay nodes that do not successfully decode a signal received from a source node is selected as F j = {ST l1 , ST l2 ,... , ST lj- 1-n }, and 1 ≦ l 1 <l 2 <. It can be assumed that. <l j -1-n ≤ j -1.

For each n, a possible set of sizes n

Figure pat00020
Therefore, the possible set of D j may be 2 j −1 . Now, below, the probability of blackout of the set D j is calculated.

Considering the node ST km (1 ≦ m ≦ n) including the set D j , ST km is one from the main source node PT and ST k1 , ST k2 ,. It can be seen that (m−1) signals are received from the sub source node of ST km −1 , and m signals are received in total. Since ST kg (1≤g≤m-1) successfully decodes the signal of the main source node PT, the signal x p of the main source node and its own signal x s , kg can be combined, which is It can be expressed as

Figure pat00021

On the other hand, the received signal at ST km may be represented by Equation 10 below because of the transmission of ST kg .

Figure pat00022

When the instantaneous SNR is obtained from the above equation (10),

Figure pat00023

Therefore, the instantaneous SNR at the output by the SC (selection combining) technique at ST km is

Figure pat00024

Can be

Next, the achievable rate between PT and ST km can be expressed by the following equation.

Figure pat00025

Here, N + 1 means that the entire transmission is made in a time slot divided into N + 1. Since ST km can successfully decode the signal of the source node, R STkm can be greater than the target velocity R of the system. Therefore, the probability in this case can be calculated as follows.

Figure pat00026

here,

Figure pat00027
to be.

On the other hand, according to equations (7) and (8), the probability of equation (13)

Figure pat00028
Can be given as

Figure pat00029

here,

Figure pat00030
to be.

now,

Figure pat00031
To calculate, random variable
Figure pat00032
Cumulative density function (CDF) is required. Using the general definition of CDF, the following equation can be obtained.

Figure pat00033

Using Equations 15 and 16, Equation 14 may be as follows.

Figure pat00034

If m = 1, Equation 17 is

Figure pat00035
As can be simplified as follows, the probability of the set D j can be expressed as follows.

Figure pat00036

As described above, the probability of the set D j can be theoretically calculated, and the probability of the set F j can also be calculated as follows.

In consideration of ST lb (1 ≦ b ≦ j -1-n) belonging to the set F j , assume km −1 <lb <km (1 <m <n). In this case, ST lb is one main source node signal from PT and ST k1 , ST k2 ,... (M-1) sub-source node signals may be received from ST Km −1 , and m source node signals may be received in total. Using the same method as the set D j , ST lb, which has not successfully decoded the source node signal, can be represented as follows.

Figure pat00037

If l b <k 1 , since ST lb receives a signal only from PT, Equation 19 can be expressed as follows.

Figure pat00038

In addition, when l b > k n , node ST lb may receive a source node signal from all nodes belonging to set D j , and Equation 19 may be expressed as follows.

Figure pat00039

From Equations 19 to 21, the probability of the set F j can be expressed as follows.

Figure pat00040

Similar to the case of l b > k n , ST j and SR j can receive signals from all nodes belonging to set D j , therefore, the probability that decoding is not successful in ST j and SR j is Can be represented.

Figure pat00041

Figure pat00042

Here, when j = 1, equations 23 and 24 are

Figure pat00043
,
Figure pat00044
Each can be expressed simply as

When the source node signal is correctly decoded in ST j , the main source node signal and the signal to be transmitted by ST j are combined and transmitted, where the combined signal may be expressed as follows.

Figure pat00045

In SR j , a received signal may be represented as follows because of transmission of ST j .

Figure pat00046

If SR j successfully decodes the main source node signal,

Figure pat00047
May be eliminated from Equation 26, and through Equation 27,

Figure pat00048

Therefore, the achieved transmission rate between ST j and SR j can be given as follows.

Figure pat00049

Equation 28 may indicate a case where the node SR j incorrectly recovers x s , j , which is shown in Equation 29.

Figure pat00050

If SR j or ST j does not correctly decode x p or the ST j -SR j link is in a suspended state, SR j cannot successfully recover x s , j . Therefore, the total stopping probability in SR j from Equations 18, 22 to 24 can be expressed as follows.

Figure pat00051

If the definition of the interrupt probability of the sub node system is the same as the probability that all the sub source nodes are in the suspended state, the following equation may be obtained.

Figure pat00052

Considering the main source node link, it is possible to define a set of sub-source nodes having a set D that successfully decodes the source node signal and a set F that does not successfully decode. Respectively, 0 ≦ n ≦ N and 1 ≦ k 1 <.. < k n &lt; N and 1 &lt; l 1 &lt; Suppose D = {ST k1 , ST k2 , ..., ST kn }, satisfying <l (Nn) ≤N, F = {ST l1 , ST l2 , ..., ST l (Nn) } Similar to Equations 18, 22, and 23, the following equations can be obtained.

Figure pat00053

Figure pat00054

Figure pat00055

Using a total probability thorem, the average interruption probability between the main source node and the main destination node can be expressed as follows.

Figure pat00056

Hereinafter, the diversity gain of a cooperative communication system according to an embodiment of the present invention will be theoretically calculated.

The node ST j (1 ≦ j ≦ N) divides the transmission power P into α j and 1-α j and allocates the signal to the signal of the main node source and the signal to be transmitted by itself. If αj

Figure pat00057
If is satisfied, ST j is referred to as a non-diversity relay source node (non-diversity relay). If there are q non-diversity sub source nodes among the N sub source nodes, the attainable diversity gain for the main source node may be N + 1-q. This is demonstrated below.

To this end, D = {ST k1 , ST k2 ,... , ST kn }, F = {ST l1 , ST l2 ,.. , ST lN −n }, and it is assumed that w (0 ≦ w ≦ n) non-diversity sub source nodes exist in the set D and qw non-diversity sub source nodes exist in the set F. From equations 16 and 32, high SNR

Figure pat00058
In Equations 32 to 34
Figure pat00059
,
Figure pat00060
And
Figure pat00061
Can be represented as follows.

Figure pat00062

Figure pat00063

Figure pat00064

here,

Figure pat00065
,
Figure pat00066
,
Figure pat00067
to be.

According to equations 36 to 38, the probability of interruption of the main source link for each possible set of D can be approximated as follows.

Figure pat00068

In addition, in this case all sub-source nodes can successfully decode or D = {ST k1 , ST k2 ,... , ST kn }, F = {Φ}, so the probability of interruption can be expressed as

Figure pat00069

High SNR

Figure pat00070
Equation 39 described above can be approximated as follows.

Figure pat00071

here,

Figure pat00072
to be.

Furthermore, it can be represented by (Nn) (mw) + n-w + 1≥N-w + 1≥N-q + 1, so that high SNR from equations (35), (39) and (41)

Figure pat00073
in
Figure pat00074
Can be approximated as

Figure pat00075

Where c is a constant.

Accordingly, the diversity gain can be expressed as follows.

Figure pat00076

Hereinafter, the diversity gain obtained in the sub node system will be described. In a cooperative relay system according to an embodiment of the present invention, a diversity gain of 1 may be obtained at each subnode, and a diversity gain of N may be obtained in a subnode system. Prove it with the attached equation.

To this end, D = {ST k1 , ST k2 ,... , ST kn }, F = {ST l1 , ST l2 ,.. , ST lN −n }, and if w (0 ≦ w ≦ n) non-diversity sub source nodes exist in the set D, then D = {ST k1 , ST k2 ,... , ST kw }.

First, high SNR

Figure pat00077
In Equation 18, 22 is approximated as follows.

Figure pat00078

Figure pat00079

here,

Figure pat00080
to be.

Next, from equations 23, 24, and 29,

Figure pat00081
Can be approximated as

Figure pat00082

here,

Figure pat00083
,
Figure pat00084
to be.

From Equations 44 to 46, the stopping probability of each of the possible sets Dj can be expressed as follows.

Figure pat00085

In a possible set D j of 2 j-1 , all nodes ST 1 , ST 2 ,... , Since ST j -1 can be successfully decoded, n = j-1 and Equation 47 can be expressed as follows.

Figure pat00086

In all cases of the set D j , (jn-1) (mw) + 1 ≧ jn ≧ 1 and therefore, high SNR

Figure pat00087
Suspension Probability of ST j -SR j in Equation 29 in Equation 29
Figure pat00088
Can be written as

Figure pat00089

Where c j is a constant.

Therefore, the interruption probability of the sub node in Equation 21 may be expressed as follows.

Figure pat00090

Accordingly, the diversity gain of the subnode system having N pairs of ST j -SR j , which is a pair of subnodes, may be determined as 1 and N, respectively.

Hereinafter, the simulation result of the transmission and reception apparatus according to an embodiment of the present invention will be described with the accompanying drawings. To this end, Monte-Carlo simulation is used, where the sub source node is placed between the main source node and the main destination node, and the distance between the sub source node and the main transmitting node is normalized to one. In addition, in the plurality of sub source nodes, the distance between each sub source node and the main source node is j / (N + 1) (where j means the index of the sub node), and the path loss between each node (β ) And 3, the target speed was set to 1.

FIG. 6 is a graph illustrating an average SNR of a sub source node as a stopping probability with respect to dB according to an embodiment of the present invention. In this simulation, the number of sub source nodes N varies from 0-3, and the power weight α for the transmission signal of the main source node is 0.95. In this case, when N = 0, the main source node directly transmits a signal to the main destination node without the help of a sub source node. As the value of N increases, the main source node plays a relay role for the signal transmitted by the main source node. This means that the number of sub source nodes is increased. Referring to FIG. 6, it can be seen that the main source node has a higher SNR when the main source node is cooperated by the sub source node than when directly transmitting a signal without the help of the sub source node.

7 is a view illustrating a combination of a transmission signal of a main source node and a transmission signal of a sub source node in a plurality of sub source nodes according to an embodiment of the present invention, respectively. It is a graph of the stopping probability according to the case of changing the power weight corresponding to. Referring to FIG. 7, it can be seen that the cooperative communication system according to an embodiment of the present invention exhibits poor operation performance when [α1, α2] = [0.8, 0.8]. this is

Figure pat00091
ego,
Figure pat00092
In this case, therefore, the diversity diversity order is equal to one. However, in the cooperative communication system according to an embodiment of the present invention, when [α1, α2] = [0.9, 0.8] (or [α1, α2] = [0.8, 0.9]),
Figure pat00093
(or
Figure pat00094
In this case, the diversity order is larger than 1 with the help of the sub source node. In addition, when [α1, α2] = [0.9, 0.9], since it is three of the diversity gains that can be achieved in the high SNR region, it has the best operating performance.

8 and 9 are graphs comparing theoretical calculation values and simulation result values of the probability of interruption in a cooperative communication system according to an exemplary embodiment of the present invention.

In FIG. 8, it is assumed that the sub source node and the sub destination node are composed of three pairs, and each sub source node has a transmission signal of the main source node and a transmission signal of each sub source node by the same power weight α. Assume to combine As shown in FIG. 8, the operation performance of the sub source node increases as the value α decreases. This is because the power weight value (1-α) applied to the transmission signal of the sub source node increases. In addition, simulations and theoretical calculations can be found to match well. In FIG. 9, the number of sub source nodes is four, and the power weight value α is changed. Through this, the change in the probability of interruption according to the change in the power weight value α can be seen, and the diversity gain is equal to each other.

10 and 11 are graphs illustrating the stopping probabilities of each sub source node and a sub destination node according to an embodiment of the present invention. Through this, it can be seen that the theoretical results and the simulation results show the very same value, and as the α j (1 ≦ αj ≦ 3) decreases, the operation performance of the sub source node and the sub destination node increases. In addition, the first sub source node and the sub destination node do not depend on α 2 , α 3 , the second sub source node and sub destination node depend on α 1 , and the third sub source node and sub destination node are α 1 And α 2 .

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the above-described specific embodiment, the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

100: cooperative communication system 110: main source node
120-1,... , 120-N: sub-source node
125-1,... , 125-N: sub-destination node
130: main destination node
210: interface unit 220: control unit

Claims (9)

In the resource sharing method in a cooperative communication system including a plurality of nodes,
The main source node broadcasting a first signal through a first time slot of a preset frequency band;
Receiving, by a sub-source node, the signal and combining it with a second signal to be transmitted by the sub-source node, and broadcasting the combined signal through a second time slot of the preset frequency band; And
The main destination node corresponding to the main source node receives and processes the first signal transmitted through the first time slot and the combined signal transmitted through the second time slot, and corresponds to the sub source node. And receiving, by the sub-destination node, the combined signal and processing the second signal. The method of claim 1,
The sub-source node and the sub-destination node each comprises a plurality of pairs corresponding to each other. The method of claim 2,
The plurality of sub-source nodes sequentially use the time slots after the first time slot to transmit a combined signal to which a signal to be transmitted and the first signal are combined.
The plurality of sub-destination nodes corresponding to the plurality of sub-source nodes receive a combined signal transmitted through each time slot to process signals of the corresponding sub-source nodes. . The method of claim 1,
The combined signal is,
A resource in a cooperative communication system, wherein the first signal and the second signal are linearly combined by applying a power weight corresponding to each of the first signal and the second signal as shown in the following equation. How to share:
Figure pat00095

Here, x p is the first signal transmitted from the main source node, x s is the second signal to be transmitted from the sub source node, P is the transmission power of the sub node, α and 1-α are the division of the transmission power. The coefficient, x c, is a combined signal in which the first signal and the second signal are combined. In the resource sharing method of the sub-source node to relay the signal transmitted from the main source node,
Receiving, by the sub source node, a first signal broadcast from the main source node through a first time slot of a preset frequency band;
Linearly combining the first signal and the second signal by applying power weights corresponding to each of the received first signal and a second signal to be transmitted by the sub source node; And
And broadcasting, by the sub source node, the combined combined signal through a second time slot of a preset frequency band. The method of claim 5,
The combining step,
A signal processing method comprising combining the first signal and the second signal using the following equation:
Figure pat00096

Here, x p is the first signal transmitted from the main source node, x s is the second signal to be transmitted from the sub source node, P is the transmission power of the sub node, α and 1-α are the division of the transmission power. The coefficient, x c, is a combined signal in which the first signal and the second signal are combined. In the resource sharing method of the main destination node for receiving a signal transmitted by the main source node through a plurality of sub source nodes,
Receiving, by the main destination node, a first signal broadcast from the main source node through a first time slot of a preset frequency band; And
And receiving and processing, by the main destination node, a combined signal transmitted by the sub source node through a second time slot of the preset frequency band.
The combined signal is a resource sharing method of a main destination node, characterized in that the sub-source node receives the first signal and combines with the second signal to be transmitted. The method of claim 7, wherein
The combined signal is,
Signal processing method characterized in that it is calculated using the following equation:
Figure pat00097

Here, x p is the first signal transmitted from the main source node, x s is the second signal to be transmitted from the sub source node, P is the transmission power of the sub node, α and 1-α are the division of the transmission power. The coefficient, x c, is a combined signal in which the first signal and the second signal are combined. An interface unit configured to receive a first signal broadcast by the main source node through a first time slot of a preset frequency band;
And a controller configured to combine the signal to be transmitted with the first signal to generate a combined signal and to control the interface unit to broadcast the combined signal through a second time slot of the frequency band.
KR20100120084A 2010-11-29 2010-11-29 Apparatus for sharing resource and method using thereof KR101236976B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
KR20100120084A KR101236976B1 (en) 2010-11-29 2010-11-29 Apparatus for sharing resource and method using thereof
PCT/KR2011/008929 WO2012074239A2 (en) 2010-11-29 2011-11-22 Resource sharing device and resource sharing method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR20100120084A KR101236976B1 (en) 2010-11-29 2010-11-29 Apparatus for sharing resource and method using thereof

Publications (2)

Publication Number Publication Date
KR20120058349A true KR20120058349A (en) 2012-06-07
KR101236976B1 KR101236976B1 (en) 2013-02-26

Family

ID=46172362

Family Applications (1)

Application Number Title Priority Date Filing Date
KR20100120084A KR101236976B1 (en) 2010-11-29 2010-11-29 Apparatus for sharing resource and method using thereof

Country Status (2)

Country Link
KR (1) KR101236976B1 (en)
WO (1) WO2012074239A2 (en)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20090026965A (en) * 2007-09-11 2009-03-16 울산대학교 산학협력단 System for cooperative relaying without reducing spectral efficiency
KR101081253B1 (en) * 2009-01-30 2011-11-08 서울대학교산학협력단 Apparatus and Method for communicating cooperatively using network coding in Uplink System comprised of multiple relay device

Also Published As

Publication number Publication date
KR101236976B1 (en) 2013-02-26
WO2012074239A3 (en) 2012-09-13
WO2012074239A2 (en) 2012-06-07

Similar Documents

Publication Publication Date Title
Nguyen et al. Energy harvesting-based spectrum access with incremental cooperation, relay selection and hardware noises
CN101207621B (en) Power distribution method for reducing interruption probability in AF-DSTC collaboration communication protocol
CN103916929A (en) Neighbor finding method for directional Ad Hoc network
KR20130036937A (en) A method of managind interference of relay node and a relay node managing interference in a multi-hop network
EP2095252B1 (en) Piggyback networks
Li et al. Spectrum sharing with distributed relay selection and clustering
Shin Performance evaluation of parallel opportunistic multihop routing
JP5408254B2 (en) Wireless communication system, base station, relay station, and wireless communication method
CN113923787A (en) User self-adaptive access method and device for realizing large-scale URLLC
KR101236976B1 (en) Apparatus for sharing resource and method using thereof
Guimaraes et al. Best relay selection in cooperative spectrum sharing systems with multiple primary users
CN102769511A (en) Network coding cooperation method based on forward amplification transport protocol
CA2672416C (en) System and method for relaying turbo-coded piggyback messages
Jung et al. Analysis of spatial pipelining in opportunistic large array broadcasts
CN111866985B (en) Hybrid relay selection method for dense communication networks
Deng et al. Relay selection in wireless cooperative networks using decode-and-forward transmission
EP3855642A1 (en) Ad-hoc hf time frequency diversity
JP2010068505A (en) Method and system of scheduling for multihop relay in wireless communication
Chen et al. Efficient Cooperative MIMO Paradigms for Cognitive Radio Networks
Zhou et al. Alternate Distributed Beamforming with Power Allocation for Decode-and-Forward Multirelay Systems Using Buffers
Chen et al. Cooperative MIMO paradigms for cognitive radio networks
US20220360318A1 (en) Radio communication apparatus, and radio communication method
NGUYEN et al. Energy Harvesting-based Spectrum Access With Incremental Cooperation, Relay Selection and Hardware Noises
Rathnasamy et al. Channel and Relay Assignment Using Kruskal Algorithm in LTE Networks
Li et al. Optimal Set of Multiple Relays and Distributed Self-Selection in Cooperative Networks

Legal Events

Date Code Title Description
A201 Request for examination
E902 Notification of reason for refusal
E701 Decision to grant or registration of patent right
GRNT Written decision to grant
FPAY Annual fee payment

Payment date: 20151221

Year of fee payment: 4

FPAY Annual fee payment

Payment date: 20170221

Year of fee payment: 5

LAPS Lapse due to unpaid annual fee