KR20180040321A - Multiple input multiple output power line communication system and transmitter and receiver included therein - Google Patents

Abstract

A multi-input multi-output power line communication system according to one embodiment of the present invention comprises: a power line; a transmitting terminal which is connected to the power line, has a plurality of transmitting ports and transmits pilot to the power line; and a receiving terminal which is connected to the power line, receives the pilot from the power line with a plurality of receiving ports more than the number of transmitting ports, and estimates a channel matrix having a plurality of channel transmission functions from the pilot. The receiving terminal inserts 0 into a Grassmannian codebook to generate a first codebook, changes a location of a factor contained in the first codebook or removes a part of the factor contained in the first codebook to generate a second codebook, extracts an index of beamforming vector from the second codebook, and transmits the index to the transmitting terminal. According to the present invention, the performance of multi-input multi-output communications can be improved in a structure where a transmitting port and a receiving port are asymmetric to each other.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a multi-input / output (I / O) power line communication system,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a MIMO power line communication system, and a transmitter and a receiver included therein.

Power Line Communication (PLC) is a system that converts a communication signal into a high frequency signal of several hundred Hz to several tens of MHz through a power line installed in a home or office, and transmits the signal by using a dedicated device. It says.

That is, the power line communication is a convenient and economical communication method that can be used as an external network such as an Internet connection or a home network such as a home network by plugging a power outlet into a home power outlet without installing a costly dedicated line or a backbone network.

Power line communication technology enables remote control of electronic devices using a remote control, control of household appliances through mobile phones or the Internet from outside, security such as lighting control, intrusion detection, remote disconnection of gas valves, It is attracting attention as home automation such as device control, automatic remote meter reading, and remote monitoring. In particular, powerline communication technology is attracting attention as a technology suitable for intelligent power meter infrastructure (AMI).

Power line communication can be modeled on the basis of a single network to which two power lines are connected. Since the number of ordinary power lines is three, power line communication can realize multiple input multiple output (MIMO) communication by utilizing a plurality of networks. Therefore, researches that apply MIMO technology to power line communication technology are actively being carried out.

Unlike a general communication system, a power line communication system can have a structure in which a transmitting port and a receiving port are asymmetric with respect to each other. For example, the transmit port may be constrained by Kirchhoff's law, and the receive port may utilize a CM (Common Mode) port using ground.

Japanese Patent Application Laid-Open No. 10-2011-0050642

An embodiment of the present invention provides a multi-input / output power line communication system capable of improving the performance of multi-input / output communication when a transmission port and a reception port are asymmetric with each other, and a transmitting end and a receiving end included therein.

A multi-input / output power line communication system according to an embodiment of the present invention includes: a power line; A transmitting terminal connected to the power line and having a plurality of transmitting ports and transmitting a pilot with the power line; And a receiver for receiving the pilot from the power line and having a plurality of reception ports greater than the number of the plurality of transmission ports and estimating a channel matrix having a plurality of channel transfer functions from the pilot; Wherein the receiving end inserts 0 in a Grassmannian codebook to generate a first codebook, changes the position of an element included in the first codebook, or changes a position of a part of the element included in the first codebook To extract a beamforming vector index from the second codebook, and to transmit the index to the transmitting end.

For example, the Grassmannian codebook may include four matrices each having a size of 1X2, and the first codebook may include first, second, third, and fourth , 9th, 10th, 11th and 12th matrices and fifth, sixth, seventh and eighth matrices each of which includes 0 and 2 elements each of which is included in at least one of the 4 matrices have.

For example, the number of the plurality of transmission ports is three, the number of the plurality of reception ports is four, the channel matrix has a size of 3X4, and the transmitter transmits a 3x3 temporary channel matrix Can be estimated.

A multi-input / output power line communication receiving end according to an embodiment of the present invention includes: a plurality of transmission ports connected to a power line; A pilot generator for estimating a temporary channel matrix, generating a pilot and transmitting the pilot on the power line; A first codebook is generated by inserting 0 into a Grassmannian codebook, a position of an element included in the first codebook is changed, or a part of elements included in the first codebook is removed, A codebook converter for generating a codebook; And a diversity gain calculator for receiving an index of a beamforming vector generated from the second codebook from the power line and calculating a beamforming diversity gain based on the index; . ≪ / RTI >

A multi-input / output power line communication transmitting end according to an embodiment of the present invention includes: a plurality of receiving ports connected to a power line; A channel matrix estimator for receiving a pilot from the power line and estimating a channel matrix having a plurality of channel transfer functions from the pilot; And a Grassmannian codebook to generate a first codebook, change a position of an element included in the first codebook, or remove a part of elements included in the first codebook, An index generator for generating an index of a beamforming vector from the second codebook and transmitting the index to the powerline; . ≪ / RTI >

According to the present invention, the performance of the MIMO communication can be improved in a structure in which the transmission port and the reception port are asymmetric with each other.

Also, the MIMO power line communication system according to an embodiment of the present invention can reduce the amount of information fed back for MIMO beamforming, thereby efficiently reducing the complexity of the receiving end and obtaining a signal-to-noise ratio gain efficiently .

1 is a block diagram of a MIMO communication system according to an embodiment of the present invention.
2 is a diagram illustrating communication between a transmission port and a reception port included in the MIMO power line communication system according to an embodiment of the present invention.
3 is a diagram illustrating a transmitting end and a receiving end included in a MIMO power line communication system according to an embodiment of the present invention.
4 is a diagram illustrating a channel matrix and a codebook used in a MIMO power line communication system according to an embodiment of the present invention.
5 is a diagram illustrating a channel matrix and a codebook for beamforming with multiple streams.

The following detailed description of the invention refers to the accompanying drawings, which illustrate, by way of illustration, specific embodiments in which the invention may be practiced. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly explained. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in order that those skilled in the art can easily carry out the present invention.

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

Referring to FIG. 1, a MIMO power line communication system according to an embodiment of the present invention may include a power line 100, a transmitter 200, and a receiver 300.

The power line 100 may include a phase line P, a neutral line N, and a protective earth line PE. Here, the phase line P may be replaced with a line L.

The transmitting terminal 200 is connected to the power line 100 and can transmit a pilot to the receiving terminal 300 with three transmitting ports. The transmitting terminal 200 may orthogonally transmit the pilot so that the receiving terminal 300 can estimate the channel matrix for the three transmitting ports despite Kirchhoff's law.

The three transmission ports include a port PN connected to the phase line P and the neutral line N, a port N-PE connected to the neutral line N and the protective earth line PE, (P-PE) to which a protective earth line (P) and a protective earth line (PE) are connected.

The receiving end 300 can receive the pilot from the transmitting end 200 connected to the power line 100 and has four receiving ports and estimate a channel matrix having a plurality of channel transfer functions from the pilot. The channel matrix is the H matrix shown in FIG.

The four reception ports include a port PN connected to the phase line P and the neutral line N, a port N-PE connected to the neutral line N and the protective earth line PE, A port P connected to a protective earth line P and a port CM connected to a ground line and a power line 100. [

행렬을 추정할 수 있다.Also, the receiver 300 may transmit a sounding signal to the transmitter 200. The transmitting terminal 200 estimates the sounding signal and uses channel reciprocity to generate a signal

The matrix can be estimated.

Here, the channel matrix estimated by the receiving terminal 300 may have a size of 3 × 4, and the channel matrix estimated by the transmitting terminal 200 may have a size of 3 × 3. For 3X4 MIMO communication, the receiver 300 may feed back the index of the beamforming vector to the transmitter 200, and the transmitter 200 may estimate the channel matrix corresponding to the channel matrix estimated by the receiver 300 . Accordingly, the MIMO beamforming system can perform MIMO beamforming so as to obtain a high signal-to-noise ratio (SNR) gain while the complexity of the receiver 300 is reduced.

The MIMO power line communication system according to an embodiment of the present invention can reduce the index of the beamforming vector fed back from the receiving end 300 to the transmitting end 200, thereby efficiently performing MIMO beamforming.

행렬이며, 송신단(200)에 공유될 수 있다.Specifically, the receiver 300 may generate a first codebook by cyclically inserting 0 into a Grassmannian codebook designed by glassmanian packing. The Grassmannian codebook is C shown in Fig. Here, the codeword can be made up of unitary vectors having the greatest distance from each other. 4, the first codebook

And may be shared by the transmitting end 200. [

행렬 또는

행렬이다.Thereafter, the receiver 300 changes the position of an element included in the first codebook or removes a part of the elements included in the first codebook so as to match the channel matrix estimated by the transmitter 200, Can be generated. Here, the second codebook corresponds to the codebook shown in FIG. 4

Matrix or

It is a matrix.

이다. 상기 인덱스는 송신단(200)이 수신단(300)이 추정한 행렬에 대응되는 행렬을 추정하게 하는 정보이다.The receiving end 300 may generate an index of a beamforming vector from the second codebook so as to be suitable for the channel matrix estimated by the transmitting end 200 and transmit the index to the transmitting end 200. 4,

to be. The index is information for allowing the transmitting end 200 to estimate a matrix corresponding to the matrix estimated by the receiving end 300.

2 is a diagram illustrating communication between a transmission port and a reception port included in the MIMO power line communication system according to an embodiment of the present invention.

Referring to FIG. 2, each of the first through third transmission ports 211, 212, and 213 may form a channel with each of the first through fourth reception ports 311, 312, 313, and 314.

Meanwhile, the MIMO communication system according to an embodiment of the present invention may have a Frequency Division Duplex (FDD) scheme and / or a TDD (Time Division Duplex) scheme.

3 is a diagram illustrating a transmitting end and a receiving end included in a MIMO power line communication system according to an embodiment of the present invention.

3, the transmitting terminal 200 includes first to third transmitting ports 211, 212 and 213, a pilot generating unit 220, a codebook converting unit 230, and a diversity gain calculating unit 240 can do.

The first to third transmission ports 211, 212, and 213 may be connected to the power line 100.

The pilot generation unit 220 may estimate a 3x3 temporal channel matrix, generate a pilot, and transmit the pilot to the power line 100. [ Here, the pilot generator 220 may estimate the temporary channel matrix using the sounding signal received from the receiver 300.

The codebook conversion unit 230 generates a first codebook by inserting 0 into a Grassmannian codebook, changes the position of the element included in the first codebook, or changes the position of an element included in the first codebook So that the second codebook can be generated. If the index generator 330 generates the first and second codebooks, the codebook converter 230 may utilize the first and second codebooks generated without generating the first and second codebooks.

The diversity gain calculator 240 may receive the index of the beamforming vector generated from the second codebook from the power line 100 and calculate the beamforming diversity gain based on the index. Here, the beamforming diversity gain is a parameter for MIMO beamforming, and is a parameter corresponding to the complexity of the receiving end 300 and the signal-to-noise ratio gain.

3, the receiver 300 may include first through fourth receive ports 311, 312, 313, and 314, a channel matrix estimator 320, and an index generator 330.

The first to fourth receiving ports 311, 312, 313 and 314 may be connected to the power line 100.

The channel matrix estimator 320 may receive a pilot from the power line 100 and estimate a 3x4 size channel matrix having a plurality of channel transfer functions from the pilot. In addition, the channel matrix estimator 320 may transmit a sounding signal for estimating a 3x3 channel matrix on the power line 100 by the transmitter 200. [

The index generator 330 generates a first codebook by inserting 0 into a Grassmannian codebook, changes the position of the element included in the first codebook, or changes the position of the element included in the first codebook To generate a second codebook, generate an index of a beamforming vector from the second codebook, and transmit the index to the powerline 100. If the first and second codebooks are generated in the codebook converter 230, the index generator 330 may utilize the first and second codebooks generated without generating the first and second codebooks.

4 is a diagram illustrating a channel matrix and a codebook used in a MIMO power line communication system according to an embodiment of the present invention.

Referring to FIG. 4, the grammar codebook may include four matrices each having a size of 1x2. The first codebook includes first, second, third, fourth, ninth, tenth, eleventh and twelfth matrices each including one of the four matrices and 0, A fifth, a sixth, a seventh and an eighth matrix including two elements included in at least one and 0s.

5 is a diagram illustrating a channel matrix and a codebook for beamforming with multiple streams.

Referring to FIG. 5, E represents an error, and the remainder is similar to the channel matrix and codebook shown in FIG. In other words, the MIMO communication system according to an embodiment of the present invention not only includes a case where the structures of the transmitter and the receiver are asymmetrical to each other, but also includes a case where the transmitter and the receiver know information The present invention can be applied to cases where information is asymmetric with respect to each other.

Meanwhile, the beamforming diversity gain calculation method using the channel matrix and the codebook illustrated in FIGS. 4 and 5 can be the same as the beamforming diversity gain calculation method in the general MIMO technique, and can be referred to from the following documents have.

D. Schneider, J Speidel, L. Stadelmeier, and D. Schill, "Precoded Spatial Multiplexing MIMO for Inhome Power Line Communications ", Prec. IEEE Global Telecommunications Conference (GLOBECOM), Now. 2008

D. Love, J. Heath, R. W., and T. Strohmer, "Grassmannian Beamforming for Multiple-Input Multiple-Output Wireless Systems", IEEE Transactions on Information Theory, vol. 49, no. 10, pp. 2735-2745, Oct. 2008

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Anyone can make various variations.

100: Power line
200: transmitting end
211, 212, 213: first to third transmission ports
220:
230: codebook conversion section
240: Diversity gain calculating section
300: Receiver
311, 312, 313, 314: first to fourth receiving ports
320: channel matrix estimator
330: index generation unit

Claims (5)

Power line;
A transmitting terminal connected to the power line and having a plurality of transmitting ports and transmitting a pilot with the power line; And
A receiver connected to the power line and having a plurality of reception ports greater than the number of the plurality of transmission ports, receiving the pilot from the power line and estimating a channel matrix having a plurality of channel transfer functions from the pilot; / RTI >
The receiver inserts 0 in a Grassmannian codebook to generate a first codebook, changes the position of an element included in the first codebook, or removes a part of elements included in the first codebook, 2 codebook, extracts an index of a beamforming vector from the second codebook, and transmits the index to the transmitter.
The method according to claim 1,
The Grassmannian codebook includes four matrices each having a size of 1X2,
Wherein the first codebook comprises first, second, third, fourth, ninth, tenth, eleventh and twelfth matrices each including one of the four matrices and 0, and at least one of the four matrices And a fifth, a sixth, a seventh and an eighth matrix including two elements included in one and zero.
The method according to claim 1,
Wherein the number of the plurality of transmission ports is three,
The number of the plurality of receiving ports is four,
The channel matrix has a size of 3X4,
Wherein the transmitter estimates a 3x3 temporary channel matrix before transmitting the pilot.
A plurality of transmission ports connected to the power line;
A pilot generator for estimating a temporary channel matrix, generating a pilot and transmitting the pilot on the power line;
A first codebook is generated by inserting 0 into a Grassmannian codebook, a position of an element included in the first codebook is changed, or a part of elements included in the first codebook is removed, A codebook converter for generating a codebook; And
A diversity gain calculator for receiving an index of a beamforming vector generated from the second codebook from the power line and calculating a beamforming diversity gain based on the index; Output power line communication transmission terminal.
A plurality of receiving ports connected to a power line;
A channel matrix estimator for receiving a pilot from the power line and estimating a channel matrix having a plurality of channel transfer functions from the pilot; And
A first codebook is generated by inserting 0 into a Grassmannian codebook, a position of an element included in the first codebook is changed, or a part of elements included in the first codebook is removed, An index generator for extracting an index of a beamforming vector from the second codebook and transmitting the index on the power line; Output power line communication terminal.

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