KR100892611B1 - Method for generating integrated preamble for selective coding support, and digital orthogonal transmission system and method using it - Google Patents

Abstract

The present invention relates to a method for generating an integrated preamble for supporting selective encoding, a digital orthogonal transmission system using the same, and a method for encoding a specific coding scheme (for example, space-time encoding (STC)) in a digital orthogonal transmission system, particularly an OFDM transmission system. One state state diagram that can accommodate both cases, and the corresponding preamble (STC supported preamble or STC non-supported preamble) based on whether the encoding is supported or not. By generating the, it is intended to eliminate the hardware cost and power inefficiency of separately configuring / operating the preamble generator according to the STC support.

To this end, the present invention provides a method for generating an integrated preamble for selective encoding support, comprising: a control signal receiving step of receiving a control signal indicating whether a predetermined encoding scheme is supported from the outside; A state transition step of transitioning to either a preamble generation state for supporting the encoding scheme or a preamble generation state not supporting the encoding scheme according to the control signal; And a preamble generation step of generating a corresponding preamble in the transitioned state.

OFDM, STC, preamble, WiMAX, STC encoder, space-time coding

Description

Integrated Preamble Generation Method for Selective Coding Support, Digital Orthogonal Transmission System Using the Same, and Method therefor {METHOD FOR GENERATING INTEGRATED PREAMBLE FOR SELECTIVE CODING SUPPORT, AND DIGITAL ORTHOGONAL TRANSMISSION SYSTEM AND METHOD USING IT}

The present invention relates to a method for generating an integrated preamble for supporting selective encoding, a digital orthogonal transmission system using the same, and more particularly, a specific coding scheme (for example, a space-time encoding (STC) scheme) in a digital orthogonal transmission system. By generating the preamble using a single integrated state diagram regardless of whether or not to support), it is possible to solve the hardware cost and power inefficiency of separately configuring / operating the preamble generator according to whether to support the optional encoding. The present invention relates to a method for generating an integrated preamble for selective encoding support, a digital orthogonal transmission system using the same, and a method thereof.

The present invention is derived from research conducted as part of the IT Strategic Technology Development Project of the Ministry of Information and Communication and the Ministry of Information and Communication Research and Development.

FIG. 1 is a block diagram of a conventional OFDM transmission system supporting STC. In particular, FIG. 1 illustrates a configuration of a WiMAX modem transmitter, and each component operates under the control of the controller 100. Referring to FIG.

The mapper (TxMap) 101 modulates the input data by a predetermined modulation method to generate complex symbol data. Here, the complex symbol data is in the form of a complex signal consisting of an in-phase (I) signal and a quadrature-phase (Q) signal.

The data txMapData output from the mapper TxMap 101 is subchannelized in the subchannelizer TxSubChan 102.

The preamble generator # 1 (TxPreamble # 1) 103 generates a preamble by itself and merges it with data (txChData) input from the subchannelizer (TxSubChan) 102 to form a downlink subframe (PrmData). do.

The configured downlink subframe (PrmData) is input to STC encoder # 1 (TxSTC # 1) 104 and is STC encoded. Here, the STC encoder # 1 (TxSTC # 1) 104 performs STC encoding by using start timing related information and control signals of the STC zone specified in the downlink map (DL-MAP). .

The STC encoding result (stcData (0), stcData (1)) output from the STC encoder # 1 (TxSTC # 1) 104 is input to the Fast Fourier Transform (FFT) converter (TxFFT) 105 and OFDM modulated. A Guard Interval (GI) is inserted through the Cyclic Prefix (TxCP) 106 and transmitted through an antenna that is an end of the transmission system.

2A and 2B are state transition diagrams used in the implementation of a conventional transmit-side preamble generator.

As shown in FIGS. 2A and 2B, the state transition diagram used in the implementation of the conventional preamble generator is implemented in the following two types depending on whether STC is supported.

First, in the case of not supporting STC, as the control signal for initiating a new downlink is inputted, the burst 201 is set to "longPreamble" 202 or a first short of a state of generating a long training symbol (preamble). The state transition diagram is configured in the form of a transition to the "shortPreamble # 1" 203 which is the generation state of the training symbol (preamble) (see FIG. 2A).

Second, in the case of supporting STC, when a control signal for initiating a new downlink is input, the burst 211 may be set to "longPreamble" 212 or a second short training symbol, which is a state of generation of a long training symbol (preamble). The state transition diagram is configured in the form of transition to the "shortPreamble # 2" 213 which is the generation state of the (preamble) (see FIG. 2B).

Here, the difference between the shortPreamble # 1 203 and the shortPreambl # 2 213 is whether the STC preamble is generated or not. In the related art, a preamble is generated through two different state transition diagrams according to whether the STC preamble is generated. . That is, in the related art, two types of preamble generators exist according to whether STC preambles are generated, and are used independently or separately according to the purpose of use.

3 is a state transition diagram used in the implementation of the conventional transmitting side STC encoder.

As shown in FIG. 3, the state transition diagram used in the conventional STC encoder implementation is a state transition state in accordance with the input of a control signal indicating whether the STC zone is included and the start time of the STC zone. Is implemented. That is, FIG. 3 illustrates the STC execution state ("stcCtrl # 1") 302 or STC non-performance state ("nonstcCtrl # 1") 303 according to a control signal indicating whether the input new burst 301 supports STC. ) Indicates a state transition.

When a control signal indicating the start of a new downlink is input, a general burst, not a burst transmitted through the STC zone of the downlink subframe specified in the downlink map (DL-MAP), is input to the FFT converter (TxFFT). The state transitions to state "303," which is the state "nonstcCtrl # 1".

In this case, the "nonstcCtrl # 1" state indicates that each of the antenna 1 and the antenna 2 without STC encoding the 'preamble' generated from the preamble generator # 1 103 and the 'TxMap output data' merged into the preamble. A state in which an FFT converter (TxFFT) 105 is input in an appropriate form is shown.

If the preamble generated by the preamble generator # 1 (103) does not support STC encoding because the P_ALL sequence suggested in the standard is generated continuously so that the preamble generated by the preamble generator # 1 (103) may include all of the preambles. There must be a state in which the signal for 2 is forced to '0' in accordance with the control signal. This causes the complexity of system implementation / operation.

Thereafter, when the STC zone is started by the control signal, the state transitions to the "stcCtrl # 1" state 302 which is responsible for performing the STC encoding.

Here, the "stcCtrl # 1" state 302 STC encodes the 'preamble' generated in the preamble generator # 1 (TxPreamble # 1) 103 and the 'TxMap output data' merged with the corresponding preamble and antenna 1 And an operation of inputting to an FFT converter (TxFFT) 105 for each of the and antennas 2. In this case, the operation of the "stcCtrl # 1" state 302 is different from the operation of the "nonstcCtrl # 1" state 303 to perform buffering by performing STC encoding.

In a high-speed digital communication system using a WiMAX modem supporting space-time coding (STC) and an OFDM scheme with STC coding as described above, a transmission process of a preamble used for channel estimation is essentially performed every frame. Because of this, it is important to design and implement a preamble generator and STC encoder with efficient control routines and arithmetic routines, which are essential for modem design.

Therefore, the preamble generator and STC encoder are also implemented in the WiMAX modem that supports STC.The corresponding block is determined according to the presence or absence of the STC zone specified in the downlink map (DL-MAP) and the start time of the STC zone. The operation of is determined. In general, the preamble generator consists of a memory storing all kinds of preamble patterns that can be generated, and a control block for accessing the memory. Meanwhile, the STC encoder is a memory control block and a memory block for storing Fast Fourier Transform (FFT) input data using a control signal indicating the start time of the STC zone specified in the downlink map (DL-MAP). It is composed.

In this case, when the modem is configured by treating the preamble generator and the STC encoder separately, a case in which the control block of the STC encoder needs to be complicated in order to simplify the control block of the preamble generator or vice versa There is a problem that can occur. This is in contrast to hardware cost reduction and power consumption reduction, which are important factors in a wireless communication system.

The prior art as described above has a problem of increasing hardware cost and power consumption by separately configuring / operating a preamble generator according to whether STC is supported, and it is an object of the present invention to solve this problem.

That is, according to the present invention, selective encoding is generated by generating a preamble using one integrated state transition diagram regardless of whether a specific coding scheme (for example, space-time coding (STC) scheme) is supported in a digital orthogonal transmission system or the like. To provide an integrated preamble generation method for supporting selective encoding, a digital orthogonal transmission system using the same, and a method for solving the hardware cost and power inefficiency of separately configuring / operating a preamble generator according to whether or not it is supported. The purpose is.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned above can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

In order to achieve the above object, the present invention provides a preamble using an integrated state transition diagram regardless of whether a specific coding scheme (for example, space-time coding (STC) scheme) is supported in a digital orthogonal transmission system. It is characterized by generating.

More specifically, the present invention provides a method for generating an integrated preamble for selective encoding support, comprising: a control signal receiving step of receiving a control signal indicating whether a predetermined encoding scheme is supported from the outside; A state transition step of transitioning to either a preamble generation state for supporting the encoding scheme or a preamble generation state not supporting the encoding scheme according to the control signal; And a preamble generation step of generating a corresponding preamble in the transitioned state.

In addition, the present invention provides a digital orthogonal transmission system for selective encoding support, comprising: transmission symbol generation means for generating transmission symbol data; Control means for generating a control signal indicating whether a predetermined encoding scheme is supported; Preamble generating means for generating a preamble for supporting the coding scheme or a preamble not supporting the coding scheme according to the control signal and combining the transmission symbol data to generate a subframe; Encoding means for encoding a subframe for encoding support according to the control signal and encoding the subframe for encoding support by the encoding method and bypassing the subframe for non-coding support; And transmission signal generating means for generating an orthogonal transmission signal with respect to the output data of said encoding means.

The present invention also provides a digital orthogonal transmission method for selective support of space-time encoding (STC), comprising: a transmission symbol generation step of generating transmission symbol data; A preamble generation step of generating a corresponding preamble according to whether a predetermined coding scheme is supported and combining the transmitted symbol data to generate an encoding support subframe or an encoding non-support subframe; An encoding step of encoding the encoding support subframe using the encoding scheme and bypassing the encoding non-supporting subframe according to whether the predetermined encoding scheme is supported; And a transmission step of generating an orthogonal transmission signal for the encoding result for the encoding support subframe or the encoded non-supporting subframe.

As described above, the present invention is a technology used in a WiMAX base station implemented based on software wireless communication technology (SDR), and can design and implement a preamble generator capable of accommodating a commercial WiMAX standard while satisfying a WiMAX modem standard supporting STC. It's effective. That is, while the present invention enables compatibility with commercial WiMAX standards, an appropriate preamble can be generated even in the case of STC transmission.

The present invention also enables the design / implementation of a preamble generator capable of generating all kinds of preambles required by the system according to the input of the control signal in order to support the WiMAX modem system supporting STC. There is an effect of enabling the design / implementation of the necessary STC encoder to enable all kinds of encodings required.

In addition, the present invention can be implemented using only a small amount of code with less memory than any existing system including a preamble generator and an STC encoder, and also any existing system forcibly fixing a value by a control signal. In addition, the power consumption can be significantly reduced.

In addition, the present invention has the effect that it is not necessary to reconfigure the software for the base station for the WiMAX base station implemented based on software wireless communication technology (SDR). That is, the present invention has the effect that the time required for reconfiguration of the base station software is not additionally required.

The present invention satisfies the specifications of an Orthogonal Frequency Division Multiplexing (OFDM) transmission system (for example, a WiMAX modem) that supports Space Time Coding (STC) while still being able to accommodate commercial Orthogonal Frequency Division Multiplexing (OFDM) transmission system standards. The present invention relates to the design and implementation of a preamble generator, which implements a preamble generator and an STC encoder based on an integrated state diagram that enables the use of an array element (AE) that is both acceptable and efficient.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a diagram illustrating an embodiment of an OFDM transmission system for selectively supporting STC according to the present invention. In particular, FIG. 4 illustrates a configuration of a WiMAX modem transmitter supporting STC.

The present invention relates to the design and implementation of a preamble generator 403 and an STC encoder 404, and more particularly to a WiMAX modem supporting STC and a modem preamble generator (OFDM) using Orthogonal Frequency Division Multiplexing (OFDM) with STC coding. 403 and the design and implementation of the STC encoder 404.

As illustrated in FIG. 4, the OFDM transmission system supporting the STC according to the present invention includes a control unit 400, a mapper (TxMap) 401, a subchannelizer (TxSubChan) 402, and a preamble generator # 2 ( TxPreamble # 2) 403, STC Encoder # 2 (TxSTC # 2) 404, FFT Converter (TxFFT) 405, and CP Inserter (TxCP) 406.

The control unit 400 controls each component of FIG. 4, and in particular, the preamble generator # 2 (TxPreamble # 2) 403 and the STC encoder # 2 through a control signal (localCtrl (2)) indicating whether STC is supported. (TxSTC # 2) 404 is controlled.

The mapper (TxMap) 401 generates complex symbol data by modulating the input data by a predetermined modulation scheme. Here, the complex symbol data is in the form of a complex signal consisting of an in-phase (I) signal and a quadrature-phase (Q) signal.

The data (txMapData) output from the mapper (TxMap) 401 is subchannelized in a subchannelizer (TxSubChan) 402. Here, the mapper (TxMap) 401 and the subchannelizer (TxSubChan) 402 may be collectively referred to as a 'transmission symbol generator 40'.

The preamble generator # 2 (TxPreamble # 2) 403 generates a preamble by itself, merges the generated preamble with data (txChData) input from the subchannelizer (TxSubChan) 402, and downlink subframe (PrmData). ). That is, the preamble generator # 2 (TxPreamble # 2) 403 corresponds to the preamble (STC support) according to the control signal of the controller 400 (corresponding to localCtrl (2) in FIG. 4 as a control signal indicating whether or not the STC is supported). After generating a preamble or a non-STC preamble), the generated preamble is combined with data (txChData) input from the subchannelizer (TxSubChan) 402 to generate a subframe for STC support or a subframe for non-STC support.

Herein, the preamble generation process in the preamble generator # 2 (TxPreamble # 2) 403 will be described in more detail. The preamble generator # 2 (TxPreamble # 2) 403 indicates whether the control signal (STC) of the controller 400 is supported. As a control signal for indicating a corresponding to the localCtrl (2) in FIG. 4), the state transitions to either the STC support preamble generation state or the STC non-support preamble generation state, and generates the corresponding preamble in the transition state. That is, the preamble generator # 2 (TxPreamble # 2) 403 may be any one of a long preamble generation state 502, a short preamble generation state 503, or an STC short preamble generation state 504 according to a control signal. After the transition to the state of the preamble is generated in the transition state.

On the other hand, the downlink subframe (PrmData) configured as described above is input to the STC encoder # 2 (TxSTC # 2) 404, as a control signal indicating whether or not the control signal (STC) of the control unit 400 in FIG. Corresponding to localCtrl (2) of), the STC is encoded or bypassed as it is and input to the FFT converter 405. Here, the STC encoder # 2 (TxSTC # 2) 404 performs STC encoding by using start timing related information and a control signal of the STC zone specified in the downlink map DL-MAP.

The STC encoder # 2 (TxSTC # 2) 404 converts the STC encoding result (stcData (0), stcData (1)) into an FFT converter (TxFFT) when STC encoding is performed according to a control signal of the control unit 400. Output at 405. In contrast, when the STC encoder # 2 (TxSTC # 2) 404 does not perform STC encoding according to the control signal of the controller 400, the downlink subframe PrmData output from the preamble generator # 2 403 is used. ) Is bypassed to an FFT converter (TxFFT) 405.

The STC encoding result (stcData (0), stcData (1)) or downlink subframe (PrmData) output from the STC encoder # 2 (TxSTC # 2) 404 is OFDM modulated by the FFT converter (TxFFT) 405. Thereafter, a Guard Interval (GI) is inserted through the CP Inserter (TxCP) 406 and transmitted through an antenna that is an end of the modem transmitter. Here, the FFT converter (TxFFT) 405 and the CP inserter (TxCP) 406 will be collectively referred to as a 'transmission signal generator 41' for generating orthogonal transmission signals.

5 is an exemplary state transition diagram used in the implementation of the preamble generator of FIG. 4 in accordance with the present invention.

As shown in FIG. 5, the state transition diagram used in the implementation of the preamble generator 403 according to the present invention includes only one state transition diagram (“integrated state transition diagram”) regardless of whether STC is supported or not.

In the preamble generator 403 according to the present invention, when a control signal (localCtrl (2) shown in FIG. 4) indicating the start of a new downlink and whether STC is supported is input, the burst 501 generates a long training symbol (long "LongPreamble" 502, which is a preamble generation state, "shortPreamble # 1" 503, which is a short training symbol generation state (short preamble generation state), or "STCshortPreamble which is an STC short training symbol generation state (STC short preamble generation state). After transitioning to the state of any one of " 504, a corresponding preamble is generated in the transitioned state.

6 is an embodiment state transition diagram used in the implementation of the STC encoder of FIG. 4 in accordance with the present invention.

State transition diagram used in the implementation of the STC encoder 404 according to the present invention, as shown in Figure 6, the state transition according to the input of the control signal indicating whether the STC zone (Zone) and the start time of the STC zone It consists of a form. That is, FIG. 6 does not perform the STC encoding or the "stcCtrl # 2" state 602, which is a state of performing STC encoding (STC execution state) of the new burst 601 input according to a control signal indicating whether STC is supported. State transition to any one of the " nonstcCtrl # 2 " state 603, which is a non-state state (STC not performing state).

In the STC encoder according to the present invention, when a control signal (localCtrl (2) in FIG. 4) indicating the start of a new downlink and STC support is input, a downlink subframe specified in a downlink map DL-MAP is input. Transition to the " nonstcCtrl " state 603, which is a state of inputting a general burst, not a burst transmitted to the STC zone, into the FFT converter (TxFFT) 405.

Here, the specific operation of the "nonstcCtrl" state 603 is to simply buffer data without performing STC encoding on the STC unsupported subframe output from the preamble generator # 2 (TxPreamble # 2) 403, and then antenna 1 And output to the FFT converter (TxFFT) 405 for antenna 2.

The preambles generated by the preamble generator # 2 (TxPreamble # 2) 403 are included until the presence of the STC zone. However, since the preambles are generated by the control signal (localCtrl (2) in FIG. In the present invention, there is no need to force the signal for the antenna 2 to '0' in accordance with the control signal. That is, in the present invention, if it is determined that STC is not supported through the control signal (localCtrl (2) in FIG. 4), the STC encoder # 2 404 does not perform STC encoding and preamble generator # 2 403. Bypass the output of the FFT converter 405.

Thereafter, when the STC zone is started by the control signal (localCtrl (2) in FIG. 4), the state transitions to the "stcCtrl # 2" state 602 which is responsible for performing STC encoding.

Here, the specific operation of the "stcCtrl # 2" state 602 receives and buffers the STC support subframe output from the preamble generator # 2 (TxPreamble # 2) 403 and STC encodes the antenna 1 and the antenna 2, respectively. An output of the FFT converter 405 for the FFT converter 405 is output in a form suitable for input. In this case, the operation of the "stcCtrl # 2" state 602 differs from the operation of the "nonstcCtrl" state 603 in that the data is buffered by performing STC encoding.

On the other hand, the method of the present invention as described above can be written in a computer program. And the code and code segments constituting the program can be easily inferred by a computer programmer in the art. In addition, the written program is stored in a computer-readable recording medium (information storage medium), and read and executed by a computer to implement the method of the present invention. The recording medium may include any type of computer readable recording medium.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

1 is a configuration diagram of an OFDM transmission system supporting a conventional STC;

2A and 2B are state transition diagrams used in the implementation of the preamble generator of FIG. 1;

3 is a state transition diagram used in the implementation of the STC encoder of FIG.

4 is a diagram illustrating an embodiment of an OFDM transmission system for selective support of an STC according to the present invention;

5 is an exemplary state transition diagram used in the implementation of the preamble generator of FIG. 4 according to the present invention;

6 is an embodiment state transition diagram used in the implementation of the STC encoder of FIG. 4 in accordance with the present invention.

* Explanation of symbols on the main parts of the drawings

40: transmission symbol generator 41: transmission signal generator

400: control unit 401: mapper

402: subchannelizer 403: preamble generator # 2

404: STC Encoder # 2 405: FFT Converter

406: CP inserter

Claims (12)

In the integrated preamble generation method for supporting selective encoding, A control signal receiving step of receiving a control signal indicating whether a predetermined encoding scheme is supported; A state transition step of transitioning to either a preamble generation state for supporting the encoding scheme or a preamble generation state not supporting the encoding scheme according to the control signal; And A preamble generation step of generating a corresponding preamble in the transition state; The state transition step, And a transition to any one of a long preamble generation state, a short preamble generation state, or an STC short preamble generation state according to the control signal. The method of claim 1, The coding scheme is Integrated preamble generation method characterized in that the space-time coding (STC) method. The method of claim 2, The state transition step, And a transition to any one of an STC support preamble generation state or an STC non-support preamble generation state according to the control signal. delete In a digital orthogonal transmission system for supporting selective encoding, Transmission symbol generation means for generating transmission symbol data; Control means for generating a control signal indicating whether a predetermined encoding scheme is supported; Preamble generating means for generating a preamble for supporting the coding scheme or a preamble not supporting the coding scheme according to the control signal and combining the transmission symbol data to generate a subframe; Encoding means for encoding a subframe for encoding support according to the control signal and encoding the subframe for encoding support by the encoding method, and bypassing the encoding non-support subframe; And Transmission signal generation means for generating an orthogonal transmission signal with respect to the output data of the encoding means Digital orthogonal transmission system comprising a. The method of claim 5, wherein The coding scheme is Digital orthogonal transmission system characterized by the space-time coding (STC) method. The method of claim 6, The preamble generating means, And a transition to any one of an STC support preamble generation state or an STC non-support preamble generation state according to the control signal, and generate the corresponding preamble in the transition state. The method of claim 7, wherein The preamble generating means, And a transition to one of a long preamble generation state, a short preamble generation state, or an STC short preamble generation state according to the control signal. In the digital orthogonal transmission method for the selective support of space-time coding (STC), A transmission symbol generation step of generating transmission symbol data; A preamble generation step of generating a corresponding preamble according to whether a predetermined coding scheme is supported and combining the transmitted symbol data to generate an encoding support subframe or an encoding non-support subframe; An encoding step of encoding the encoding support subframe using the encoding scheme and bypassing the encoding non-supporting subframe according to whether the predetermined encoding scheme is supported; And A transmission step of generating an orthogonal transmission signal for the encoding result for the encoding support subframe or the encoded non-supporting subframe; Digital orthogonal transmission method comprising a. The method of claim 9, The coding scheme is Digital orthogonal transmission method characterized by the space-time coding (STC) method. The method of claim 10, The preamble generation step, In response to the first control signal indicating whether the STC scheme is supported, transition to one of a long preamble generation state, a short preamble generation state, or an STC short preamble generation state, and generate the corresponding preamble in the transitioned state. Digital orthogonal transmission method, characterized in that. The method of claim 11, The encoding step, And performing either STC encoding or bypass according to a second control signal indicating whether the STC scheme is supported.

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