KR20080107114A - Wireless impulse transmitter, wireless impulse receiver and transmission method in uwb-ir system - Google Patents

Abstract

A wireless impulse transmitter, a wireless impulse receiver and a transmission method in an UWB-IR system are provided to obtain a space-diversity gain always without the time-invariant condition of a wireless channel. A wireless impulse transmitter in an UWB-IR system comprises the followings: a data unit(110) in which data is stored; a space-shape coding unit(120) which processes the first single pulse string, set correspondingly to one data, through the PPM to express the data as information bit 0 or 1, and then codes/outputs the first single pulse string based on the space-shape diversity; and a multi-transmission antenna part(130) which transmits the coded signal.

Description

Wireless impulse transmitter, wireless impulse receiver and transmission method in UWB-IR system

1 is a block diagram of an ultra-wideband impulse radio system according to an embodiment of the present invention.

2 is a diagram illustrating a form of a single pulse string corresponding to information bits according to an exemplary embodiment of the present invention.

3 is a comparison of BER performance between an ultra-wideband impulse radio system and a single shape, single antenna application system according to an exemplary embodiment of the present invention.

The present invention relates to an ultra-wideband impulse radio (UWB-IR) system, and more particularly, to a wireless impulse transmitter using a space-shaped diversity coding technique, a receiver for receiving the same, and a method for transmitting a wireless impulse. The present invention compares and analyzes the performance of the conventional single-shape pulse and single-antenna technique in a multipath fading environment to quantitatively prove the effect of the coding technique using the multi-shape pulse and multi-antenna on the performance. to provide.

Ultra-wideband (UWB) is a technology used by the US Department of Defense as a military radiocommunication technology that has been of interest since the Federal Communications Commission (FCC), a US communications frequency authority, opened to private companies. It is one of the leading radio techniques that can be applied to low power application system such as the base system.

Ultra-Wide Impulse Radio (UWB-IR) is a technique that emits extremely short impulse heat with a pulse width of several nS to several tens of pS, and the energy of the emitted signal is wide ranging from low frequency to several GHz. More specifically, UWB guarantees a transmission distance of 10m to 1km while using a frequency band of 3.1 to 10.6 GHz, and is very strong even in multipath fading due to the use of such short pulses, and modulates a signal to be transmitted. Unlike the existing communication technology that modulates and amplifies and transmits the uplink signal, the baseband signal is directly modulated by an impulse string to be directly transmitted, thereby making the system simple and inexpensive.

In the conventional UWB-IR communication method, information bits are made into an impulse string and transmitted. In order to transmit the information bits, the UWB-IR is converted into a predetermined code that is repeated and formed into a chip, and then converted into a pulse string. When converting to pulse train, bit 0 and bit 1 are transmitted by using pulse position modulation (PPM) method that is shifted by delta from original position.

Other conventional prior art disclosed in addition to the conventional communication method using the single-shaped pulse and PPM method as described above is disclosed in the "wireless impulse transmitter, receiver and method" published in Republic of Korea Patent Publication No. 10-2003-0011600. The "wireless impulse transmitter, receiver, and method" selects and transmits a pulse type corresponding to an information bit to be sent using a plurality of pull shapes to transmit bit 0 and bit 1 separately.

Recently, researches have been made to improve transmission performance by applying a multi-antenna coding technique to UWB-IR to obtain a spatial diversity gain. However, the coding technique using the multi-antenna as described above has a limitation of obtaining a spatial diversity gain using only a single shape pulse.

In addition, in order to obtain spatial diversity gain in the conventional multi-antenna coding technique, there is a time-invariant constraint that the radio channel environment must not be changed while transmitting two or more consecutive pulse trains. Changing the wireless channel for successive pulse trains of H has a problem that results in a significant degradation of the performance of the system.

The present invention is to solve the conventional problems and to meet the needs of the user, a space-shaped diversity coding technique using the shape diversity and the spatial diversity of multiple antennas according to the mutual orthogonal characteristics of a plurality of orthogonal ultra-wideband pulses Is applied to a single pulse train rather than to a continuous pulse train on the time axis, so that the spatial diversity gain can always be obtained without time-invariant conditions of the radio channel.

According to a feature for achieving the above technical problem, the present invention provides a wireless impulse transmitter in an ultra-wideband impulse radio system. The wireless impulse transmitter includes a data unit for storing data; Spatial-shape to output information bit-0 or 1- of the data by PPM of the first single pulse train set corresponding to one data, and to perform spatial-shape diversity coding on the first PPM trained pulse stream Coding unit; And a multiple transmit antenna unit configured to transmit the space-shaped diversity coded signal through a first antenna and a second antenna, wherein the space-shaped diversity coding comprises: a first unit pulse shape of the PPM first single pulse train; And different combinations of a second unit pulse shape orthogonal to the first unit pulse shape and provided to the first and second antennas.

According to another feature for achieving the above technical problem, the present invention provides a wireless impulse receiver of an ultra-wideband impulse radio system. The wireless impulse receiver comprises a first path channel and a second path by combining first and second combinations of a first unit pulse shape of a first PPM pulsed sequence and a second unit pulse shape orthogonal to the first unit pulse shape. A receiving antenna receiving over a channel; The first and second unit pulse shapes captured at the first position among the first and second combinations received by the reception antenna in consideration of the first and second positions by the PPM; A matched filter unit including first and second matched filters and third and fourth matched filters for extracting first and second unit pulse shapes captured at the second position, respectively; A vector generator comprising a first generator for detecting a vector configured with the outputs of the first and second matched filters, and a second generator for detecting a vector configured with the outputs of the third and fourth matched filters; And a detector for generating a data train by detecting the position information having the largest output power by multiplying the output vectors of the first and second generators.

According to another feature for achieving the above technical problem, the present invention provides a method for transmitting a wireless impulse in an ultra-wideband impulse radio system. The wireless impulse transmission method includes the steps of: generating a first single pulse string set corresponding to one data; PPM said first single pulse train to represent information bits-0 or 1-of said data; Performing spatial-shape diversity coding on each unit pulse shape of the PPM-first single pulse train and outputting the same; Transmitting the space-shaped diversity coded first combination via a first antenna and transmitting the space-shaped diversity coded second combination via a second antenna, wherein the space-shaped diversity is transmitted. Coding generates the first and second combinations different from each other by combining the first unit pulse shape of the first single pulse and the second unit pulse shape orthogonal to the first unit pulse shape.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise. In addition, the terms “… unit”, “… unit”, “module”, “block”, etc. described in the specification mean a unit that processes at least one function or operation, which is hardware or software or a combination of hardware and software. It can be implemented as.

Now, a wireless impulse transmitter, a receiver, and a transmission method in an ultra-wideband impulse radio system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an ultra-wideband impulse radio system according to an embodiment of the present invention. As shown in FIG. 1, an ultra-wideband impulse radio system according to an exemplary embodiment of the present invention includes a transmitter 10 and a receiver 20.

The transmitter 10 includes a data unit 110, a space-shaped coding unit 120, and a multiple transmit antenna unit 130. The receiver 20 includes a matched filter unit 140 and a vector generator 150. And a detector 160.

The data unit 110 stores data to be transmitted and outputs data in an input order.

The space-shape coding unit 120 converts the data output from the data unit 110 into a space-shape diversity code (see Table 1) and outputs the data to each transmitting antenna, wherein the space-shape diversity code is space-shape. Generated by coding, Pulse Position Modulation (PPM), and spatial-shaped diversity coding.

Spatial-shaped coding transforms each incoming data into a single set of pulse trains. Here, a single pulse train is composed of a plurality of unit pulse shapes (Ns) to become a symbol for one information bit.

The PPM either leaves the single pulse string as it is or delays it by a delay value, depending on the information bit value (eg 0 or 1) of the data to be transmitted. For example, the PPM delays a single pulse string when the information bit is 1, and delays the single pulse string by a set delay value when the information bit is 0. As another example, the PPM may delay the delay value when the information bit is 1 and eliminate the delay when the information bit is 0. As a result, the PPM determines whether to delay according to the information bit value according to the setting condition.

)는 다음의 수학식 1로 나타내어진다.The transmission signal of the impulse string for the i th information bit generated by this space-shape coding and PPM (

Is represented by the following equation.

는 복수의 상호 직교 펄스 형상이며, 예컨데, 상호 직교 펄스 형상이 2개인 경우에 a = {0, 1}이 된다.

는 송신전력이며,

는 프레임간의 간격이고,

는 1개의 정보 비트를 나타내는 단일 펄스 열 상에서 펄스의 개수이다. Δ는 PPM 방식에서의 위치변환 값으로, 예로 들어 지연값이 ε이면,

이다. j는 해당 번째 프레임이다.From above

Are a plurality of mutually orthogonal pulse shapes, for example, a = {0, 1} when there are two mutually orthogonal pulse shapes.

Is the transmit power,

Is the interval between frames,

Is the number of pulses on a single pulse train representing one information bit. Δ is a position conversion value in the PPM method, for example, if the delay value is ε,

to be. j is the corresponding frame.

An example of a single pulse train generated by Equation 1 will be described with reference to FIG. 2. FIG. 2 is a diagram illustrating a form of a single pulse string corresponding to information bits according to an embodiment of the present invention. It is assumed that information bits transmitted are {1, 1, 0}. 2 illustrates an example in which the unit pulse train has eight impulses, that is, eight unit pulse shapes.

)로 공간-형상 코딩되고 Tsym0에서 시간지연이 없이 전송된다. 그리고 두 번째 정보비트 1은 첫 번째 정보 비트와 동일한 단일 펄스 열(

)로 공간-형상 코딩되고 Tsym1에서 시간지연이 없이

로 전송된다. 마지막으로, 세 번째 정보 비트 0은 첫 번째 정보 비트와 동일한 단일 펄스 열(

)로 공간-형상 코딩되고 Tsym2에서 지연값(ε)만큼 지연된 위치인 Tsym2+ε에서

로 전송된다.As shown in FIG. 2, the first information bit 1 of the information bits {1, 1, 0} is a unit pulse string (

Is space-shaped coded and transmitted without time delay in Tsym0. And the second information bit 1 is the same single pulse string as the first information bit.

Space-shape coded and without time delay in Tsym1

Is sent to. Finally, the third information bit 0 is the same single pulse string as the first information bit.

At Tsym2 + ε where it is space-shaped coded and delayed by the delay value ε in Tsym2

Is sent to.

Meanwhile, when the space-shape coding unit 120 provides the space-shape coded and PPM modulated information bits to the multiple transmit antenna unit 130, the space-shape divers to secure space diversity of two or more antennas. Use city coding techniques. In this case, the space-shaped diversity coding technique generates a space-shaped code using a single pulse train.

The space-shape code, which is a result of the space-shape diversity coding scheme, is shown in Table 1 below.

)에 대하여 수학식 1의 a가 2인 경우에 생성되는 상호 직교하는 단위 펄스 형상이다. 표 1에서 알 수 있듯이 공간-형상 다이버시티 코딩기법은 단일 펄스 열에 적용될 수 있음을 알 수 있다.Table 1 is for the case of two transmitting antennas, when the value of the i-th information bit is 1 (corresponding to the case of FIG. 2) without committing an error of generalization, it is applied to the j-th frame of the impulse string. Space-shape diversity coding technique is shown. In Table 1, Shape 0 and Shape 1 are the unit pulse shapes (

Is a mutually orthogonal unit pulse shape generated when a in Expression 1 is 2. As can be seen from Table 1, it can be seen that the spatial-shape diversity coding technique can be applied to a single pulse train.

The multiplex transmission antenna unit 130 has at least two transmission antennas ant1 and ant2 and transmits a space-shaped code as shown in Table 1 output from the space-shaped coding unit 120.

In this case, when there are two transmitting antennas, a signal transmitted through each of the antennas atnt1 and ant2 is represented by the following equation.

는 제1 안테나(ant1)를 통해 송신된 신호이고,

는 제2 안테나(ant2)를 통해 송신된 신호를 나타낸다. 여기서, 수학식 2로 나타낸 제1 및 제2 안테나(ant1, ant2)에서 송신된 신호는 동일한 송신전력 조건하에서 단일 펄스 형상 및 단일 안테나 시스템과의 성능을 비교 하기 위해 각 안테나에서의 송신전력을 1/2로 고려하였다.From above

Is a signal transmitted through the first antenna ant1,

Denotes a signal transmitted through the second antenna ant2. Here, the signals transmitted from the first and second antennas ant1 and ant2 represented by Equation 2 are set to transmit power of each antenna in order to compare the performance with a single pulse shape and a single antenna system under the same transmission power conditions. / 2 was considered.

및

를 거쳐 정합 필터부(140)에 연결된 수신 안테나에서 수신된다.The signal transmitted from the multiplex transmission antenna unit 130 is received by an antenna connected to the matching filter 140 of the receiving end 20. In this case, the signals received from the first and second antennas ant1 and ant2 to the matching filter unit 140 are channels independent of each other,

And

Received by the receiving antenna connected to the matching filter unit 140 through.

Here, if the i-th information bit and the received signal is called the j-th frame of the impulse string, and the signal received by the antenna of the matched filter unit 140 is X (t; i; j), then X (t; i; j Is represented by the following equation.

는 AWGN(Additive White Gaussian Noise; 백색 가우시안 잡음) 채널을 나타내며, 상호 독립적인 다중경로채널,

및

은 수학식 4에 관련된다.From above

Represents an Additive White Gaussian Noise (AWGN) channel, a multipath channel independent of each other,

And

Is related to equation (4).

은 분해 가능한 다중 경로의 수를,

는 디락델타(Dirac Delta) 함수를,

는 다중 경로 페이딩 계수를 나타낸다.From above

Is the number of decomposable multipaths,

Is the Dirac Delta function,

Denotes the multipath fading coefficient.

The matched filter unit 140 captures the multiple orthogonal spread shapes of the signals transmitted from the antennas ant1 and ant2 of the multiplex antenna unit 130. To this end, the matched filter unit 140 includes 2N matched filters, where N is the number of orthogonal pulse shapes transmitted through two or more transmit antennas (corresponding to a in Equation 1). Hereinafter, the matching filter unit 140 includes four matching filters 141 to 144 which extract information bits 1 and 0 according to two orthogonal pulse shapes Ptx0 (t) and Ptx1 (t) so as to correspond to Table 1. Explain that it is done.

Accordingly, the matched filters 141 to 144 of the matched filter unit 140 distinguish two orthogonal unit pulses with respect to the received signal X (t; j) for the jth frame of the impulse string, and information of 0 and 1 is used. Extract the bits separately.

That is, with respect to X (t), which is a received signal of the j-th frame for the i-th information bit, the first matched filter 141 receives the first unit pulse shape Ptx0 (t) corresponding to the information bit 1. In order to extract the first unit pulse shape Prx0 (t) of Prx0 (t), the second matching filter 142 of the second unit pulse shape Ptx1 (t) corresponding to the information bit 1 It is composed of Prx1 (t) to extract the second unit pulse shape Prx1 (t) at the receiver. The third matched filter 143 is configured of Prx0 (t-ε) to extract the first unit pulse shape Ptx0 (t-ε) corresponding to the information bit 0, and the fourth matched filter 144 is Prx1 (t-ε) is configured to extract the second unit pulse shape Ptx1 (t-ε) corresponding to the information bit 0.

The signals output from the matched filters 141 to 144 of the matched filter unit 140 are received by the vector generator 150. The signals output from the matched filters 141 and 142 according to the information bits are the vector generator 150. ) Is input to the first generator 151, and the signal output from the matched filters 143 and 144 is input to the second generator 152 of the vector generator 150.

The first and second generators 151 and 152 detect the j-th frame of the impulse string for the i-th information bit received using the matching filters 141 to 144 in a vector form. (t; i; j)) is represented by the following equation.

The vector shape detected by the first generator 151 is Y (t: i; j), and the vector shape detected by the second generator 152 is Y (t-ε; i; j).

는 수신단에서의 펄스 형상을,

는 정규화된 자 기상관 함수(Normalized Autocorrelation)를,

는 필터를 통과한 노이즈를 나타낸다.From above

Is the pulse shape at the receiving end,

Is the normalized autocorrelation function,

Denotes the noise passing through the filter.

Δ becomes 0 when the information bit is 1, and ε is a delay value when the information bit is 0. Therefore, for the j th frame of the impulse string for the i th information bit, the vector form of the first generator 151 is represented by Y (t), and the vector form of the second generator 152 is represented by Y (t−ε). Is expressed.

The first and second generators 151 and 152 generate the respective vector shapes and provide them to the detector 160.

The detector 160 uses a j th frame of an impulse string in a vector form generated (or detected) as expressed in Equation 5 to form a squared Euclidean norm noncoherent as in Equation 6. A noncoherent decryption technique restores data, i.e. generates a data train.

이며, 상기의 수학식 6은 이하의 등식으로 풀이된다.From above

Equation 6 is solved by the following equation.

이다.From above

to be.

의 값이 생성되는 Δ 값을 검출한다. 그러므로, 검출기(160)는 i번째 정보 비트가 1이면 Δ=0 에 단위 펄스 형상이 나타나게 되므로 Δ의 값이 0일 때가 Δ의 값이 ε일 경우보다 큰

값을 생성하게 되고, 이로써 정보 비트 1을 복원할 수 있게 된다. 여기서 i 번째 정보 비트가 0이면 반대로 Δ의 값이 ε일 경우 상대적으로 큰

값을 생성하게 되고, 이로써 정보 비트 0을 복원할 수 있게 된다.Equation 6 as described above is the largest when the value of the position transformation Δ is 0 or ε, respectively.

The value of Δ in which the value of is generated is detected. Therefore, if the i-th information bit is 1, the unit pulse shape appears at Δ = 0.

It generates a value, which allows you to recover information bit 1. If the i th information bit is 0, on the contrary, if the value of Δ is ε,

It generates a value, which allows you to restore information bit 0.

3 is shown to support the description of the above-described embodiment of the present invention. FIG. 3 shows the Bit Error Rate (BER) performance when the spatial-shape diversity coding technique is applied to a system having two transmit antennas and one receive antenna compared to the BER performance of a system having a single shape and single antenna. FIG. Doing.

In the case of fixing Eb / No (energy-to-noise ratio) as shown in FIG. 3, the system using the space-shape diversity coding technique can significantly reduce the error occurrence rate compared to a single-shape, single-antenna system. . On the other hand, when the target BER is fixed, the system using the space-shape diversity coding technique can satisfy the target BER even with low Eb / No compared to a single antenna system. Therefore, when the target BER and the Eb / No are fixed, the coverage of the system can be improved by the transmission power gain obtained by applying the space-shaped diversity coding technique.

Embodiments of the present invention are not implemented only through the above-described apparatus and / or method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiments of the present invention, a recording medium on which the program is recorded, and the like. Such implementations may be readily implemented by those skilled in the art from the description of the above-described embodiments.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

According to an embodiment of the present invention, the present invention improves transmission performance through transmission using a space-shaped diversity coding technique.

In addition, the present invention applies a space-shaped diversity coding technique to a single pulse train rather than to a continuous pulse train on the time axis, so that the spatial diversity gain can always be obtained without time-invariant conditions of the wireless channel.

Claims (10)

A wireless impulse transmitter in an ultra-wideband impulse radio system, A data unit for storing data; Spatial-shape to output information bit-0 or 1- of the data by PPM of the first single pulse train set corresponding to one data, and to perform spatial-shape diversity coding on the first PPM trained pulse stream Coding unit; And A multiple transmit antenna unit configured to transmit the space-shaped diversity coded signal through a first antenna and a second antenna, The space-shaped diversity coding is configured to provide different combinations of a first unit pulse shape of the PPM first single pulse train and a second unit pulse shape orthogonal to the first unit pulse shape to the first and second antennas. Providing wireless impulse transmitter. The method of claim 1, The space-shaped diversity coding is Provide the first antenna with a sum of the PPM first and second unit pulse shapes of a definite code, and add the sum of the PPM first single pulse shape of an inverse code and the PPM second single pulse shape of a definite code; And a wireless impulse transmitter provided to the second antenna. The method according to claim 1 or 2, The signal transmitted through the first and second antennas satisfy the following equation.

Is a signal transmitted through the first antenna,

Is a signal transmitted through the second antenna ant2. In the wireless impulse receiver of an ultra-wideband impulse radio system, Receiving through a first path channel and a second path channel a first and a second combination of a first unit pulse shape of a PPM first single pulse train and a second unit pulse shape orthogonal to the first unit pulse shape antenna; The first and second unit pulse shapes captured at the first position among the first and second combinations received by the reception antenna in consideration of the first and second positions by the PPM; A matched filter unit including first and second matched filters and third and fourth matched filters for extracting first and second unit pulse shapes captured at the second position, respectively; A vector generator comprising a first generator for detecting a vector configured with the outputs of the first and second matched filters, and a second generator for detecting a vector configured with the outputs of the third and fourth matched filters; And  And a detector for multiplying output vectors of the first and second generators to detect positional information having the largest output power to generate a data train. The method of claim 4, wherein The first combination is a sum of the first and second unit pulse shapes of a definite number, And said second combination is a sum of said PPM first single pulse shape of an inverse code and said PPM second second pulse shape of a definite code. The method of claim 5, The vector form detected by the first and second generators satisfies the following equation.

Is the first and second unit pulse shapes received by the receiving antenna,

Is a normalized autocorrelation,

Is the noise passing through the filter, Δ is the delay value corresponding to the information bit,

Is the number of decomposable multipaths,

Is the Dirac Delta function,

Multipath fading coefficient. Where a is 0 or 1. In the wireless impulse transmission method in an ultra-wideband impulse radio system, Generating a first single pulse train set in correspondence with one data; PPM said first single pulse train to represent information bits-0 or 1-of said data; Performing spatial-shape diversity coding on each unit pulse shape of the PPM-first single pulse train and outputting the same; Transmitting the space-shaped diversity coded first combination via a first antenna and transmitting the space-shaped diversity coded second combination via a second antenna, The spatial-shaped diversity coding combines a first unit pulse shape of the first single pulse and a second unit pulse shape orthogonal to the first unit pulse shape to generate the first and second combinations different from each other. Transmission method. The method of claim 7, wherein The first combination is a sum of the first and second unit pulse shapes of a definite number, And wherein the second combination is the sum of the PPM first single pulse shape of the inverse code and the PPM second single pulse shape of the definite code. The method according to claim 7 or 8, Wherein each single pulse string satisfies the following equation.

Is the transmit signal of a single pulse train,

Is a plurality of mutually orthogonal pulse shapes a = {0, 1},

Is the transmit power,

Is the interval between frames,

Is the number of pulses on a single pulse string representing one information bit, Δ is the position transformation value in the PPM scheme, j is the corresponding second frame. The method of claim 9, The signal transmitted through the first and second antennas satisfy the following equation.

Is a signal transmitted through the first antenna,

Is a signal transmitted through the second antenna ant2.

Images