KR20080028260A - Method of transmitting signals using at least one sequence - Google Patents

Abstract

A method of transmitting information using a sequence is provided to offer information to a receiver for obtaining synchronization by adding information to a synchronizing channel. A sequence for transmitting data or a control signal is generated. At least one component of the sequence is rotated. The rotated sequence is transmitted to a receiver side. At least one phase rotating component of the generated sequence has an arbitrary information value. The sequence corresponding to a synchronizing channel is generated by using at least two codes containing an orthogonal code and a scrambling code. A phase is rotated by using at least one phase rotating component. The phase rotating component corresponds to at least one of frame synchronization information and a frequency hopping pattern. The frequency hopping pattern is control information for a frequency hopping of a downlink reference signal.

Description

Method of transmitting signals using at least one sequence

1 and 2 illustrate various methods of including a P-SCH and an S-SCH in a radio frame.

3 is a view for explaining an example 2 of Method 1 of the present embodiment.

4 relates to a method of allocating a constant pattern index to S-SCH 1 and S-SCH 2 according to Method 2. FIG.

FIG. 5 relates to a method for configuring S-SCH 1 and S-SCH 2 according to Method 3. FIG.

FIG. 6 is a diagram illustrating a method of performing modulation by '+1' or '-1' on the result of Method 2. FIG.

7 shows an example of applying Method 2 to a P-SCH.

8 shows an example of applying Method 3 to a P-SCH.

FIG. 9 is a block diagram illustrating an example in which both a hopping option and information on frame synchronization are included according to the second embodiment.

10A to 10F relate to an example of rotating a phase component using different phase rotation components for a plurality of subcarriers.

11A to 11D are yet another example according to the present embodiment.

The present invention relates to a method of transmitting information using a sequence, and more particularly, to a method of constructing a channel using a sequence of excellent performance and transmitting information through such a channel.

Hereinafter, OFDM and OFDMA and SC-FDMA techniques used in the present invention will be described.

Recently, the demand for high-speed data transmission is increasing, and OFDM is a suitable method for such a high-speed transmission, and has been recently adopted as a transmission method of various high-speed communication systems. Hereinafter, orthogonal frequency division multiplexing (OFDM) will be described. The basic principle of OFDM is to divide a high-rate data stream into a large number of low-rate data streams, which are transmitted simultaneously using multiple carriers. Each of the plurality of carriers is called a subcarrier. Since orthogonality exists between the multiple carriers of the OFDM, the frequency components of the carriers can be detected at the receiving side even if they overlap each other. The high data rate data stream is converted into a plurality of low data rate data streams through a serial to parallel converter, and each subcarrier is included in the parallel data streams. After multiplying, the respective data strings are summed and sent to the receiving side. OFDMA is a multiple access method for allocating subcarriers according to a transmission rate required by multiple users in the OFD.

Hereinafter, the conventional Single Carrier-FDMA (SC-FDMA) method will be described. The SC-FDMA method is also called a DFT-S-OFDM method. Conventional SC-FDMA technique is a technique that is mainly applied to uplink. Before generating an OFDM signal, spreading is first applied to a DFT matrix in a frequency domain, and then the result is modulated by a conventional OFDM scheme and transmitted. . Several variables are defined to describe the SC-FDMA technique. N denotes the number of subcarriers transmitting the OFDM signal, Nb denotes the number of subcarriers for any user, F denotes a discrete Fourier transform matrix, or DFT matrix, s denotes a data symbol vector, x Denotes a vector in which data is distributed in the frequency domain, and y denotes an OFDM symbol vector transmitted in the time domain.

In SC-FDMA, the data symbols s are distributed using a DFT matrix before transmission. This is expressed by the following formula.

는, 데이터 심볼(s)을 분산시키기 위해서 사용된 N_b 크기의 DFT 행렬이다. 이렇게 분산된 벡터(x)에 대하여 일정한 부 반송파 할당 기법에 의해 부 반송파 매핑(subcarrier mapping)이 수행되고, IDFT 모듈에 의해 시간영역으로 변환되어 수신 측으로 전송하고자 하는 신호가 얻어진다. 상기 수 신 측으로 전송되는 전송신호는 아래 식과 같다. In Equation 1

It is a DFT matrix of size N _b used to disperse the data symbol (s). Subcarrier mapping is performed on the distributed vector x by a constant subcarrier allocation scheme, and a signal to be transmitted to the receiver is obtained by converting to the time domain by the IDFT module. The transmission signal transmitted to the receiving side is as follows.

는 주파수 영역의 신호를 시간 영역의 신호로 변환하기 위해 사용되는 크기 N의 DFT 행렬이다. 상술한 방법에 의해 생성된 신호 y는, 순환 전치(cyclic prefix)가 삽입되어 전송된다. 상술한 방법에 의해 전송 신호를 생성하여 수신 측으로 전송하는 방법을 SC-FDMA 방법이라 한다. DFT 행렬의 크기는 특정한 목적을 위해 다양하게 제어될 수 있다.In Equation 2

Is a DFT matrix of size N that is used to convert a signal in the frequency domain into a signal in the time domain. The signal y generated by the above-described method is transmitted by inserting a cyclic prefix. The method of generating a transmission signal and transmitting it to the receiving side by the above-described method is called an SC-FDMA method. The size of the DFT matrix can be variously controlled for a specific purpose.

The above description is based on the DFT or IDFT operation. However, for convenience of description, the following description uses a Discrete Fourier Transform (DFT) or Fast Fourier Transform (FFT) operation. If the number of input values of the DFT operation is a power of 2, it will be apparent to those skilled in the art that the FFT operation can be performed instead of the DFT operation. Therefore, the following FFT operation is also applicable to the DFT operation.

Hereinafter, a sequence used in the latest ^{3GPP (3 rd Generation Partnership Project)} (Long Term Evolution) LTE technology newly proposed.

Various sequences are also used in LTE systems. Hereinafter, a sequence used in the channel of LTE will be described.

In general, the first thing the terminal performs to communicate with the base station is to perform synchronization with the base station in a synchronization channel (hereinafter, referred to as 'SCH') and perform a cell search.

A series of processes for synchronizing with a base station and acquiring a cell ID to which a terminal belongs is called a cell search. In general, the cell search includes an initial cell search performed when the initial UE is powered on, and a neighbor cell where the UE in a connection or idle mode searches for an adjacent base station. It is classified as a neighbor cell search.

The chronization channel (SCH) may have a hierarchical structure. For example, a primary SCH (P-SCH) and a secondary SCH (S-SCH) may be used.

The P-SCH and the S-SCH may be included in a radio frame by various methods.

1 and 2 illustrate various methods of including a P-SCH and an S-SCH in a radio frame. In the LTE system, the SCH may be configured according to the structure of FIG. 1 or 2 according to various situations.

The P-SCH of FIG. 1 is included in the last OFDM symbol of the first subframe. In addition, the S-SCH is included in the last OFDM symbol of the second subframe.

Meanwhile, the P-SCH of FIG. 2 is included in the last OFDM symbol of the first subframe, and the S-SCH is included in the second to second OFDM symbol of the first subframe.

The LTE system may acquire time and frequency synchronization using the P-SCH. In addition, the S-SCH may include a cell group ID, frame synchronization information, antenna configuration information, and the like.

Hereinafter, a method of configuring an S-SCH proposed in the 3GPP LTE system will be described.

1 and 2, one radio frame includes two S-SCHs, and the two S-SCHs are preferably different sequences. The amount of information to be included in the S-SCH is preferably 1020 pieces of information.

More specifically, 1-bit information for frame synch, 8-bit information indicating a cell group ID, and 2-bit information indicating a transmission antenna to which a signal is transmitted are included.

The 1-bit information represents two pieces of information, the 7-bit information represents 170 pieces of information, and the 2-bit information represents three pieces of information. That is, 2 * 170 * 3 may represent 1020 pieces of information.

Although the above-mentioned S-SCH has been proposed to represent a specific number, for example, 1020 pieces of information, it is not specifically proposed how to represent the information.

The present invention has been proposed to improve the above-described prior art, and an object of the present invention is to propose a method for configuring a channel representing a specific number of information.

It is still another object of the present invention to propose a method for including various information in a channel including a synchronization channel using a sequence of superior performance.

Summary of the Invention

According to an aspect of the present invention, there is provided a method for configuring a channel used for various purposes, the method comprising: generating a sequence for transmitting data or a control signal; Rotating at least one component of the sequence; And transmitting the rotated sequence to a receiving end, wherein the at least one phase rotation component of the generated sequence is any information value.

Work of the present invention Example

The construction, operation and effects of the invention will be embodied in accordance with one embodiment of the invention described below.

Hereinafter, the first embodiment relates to a method of including a specific number of information in various channels including a synchronization channel, and the second embodiment is a method of including information about a hopping option.

First embodiment

The first embodiment proposes a method of including a specific number of information in a channel for synchronization. The channel for synchronization is preferably an S-SCH.

The first embodiment relates to a method for including a specific number of information in at least one S-SCH. 1 and 2, two S-SCHs are included in one radio frame. Hereinafter, a method of including a specific number of information in two S-SCHs for convenience of description. In addition, the first S-SCH of the two S-SCH is called "S-SCH 1", the second S-SCH is called "S-SCH 2".

This embodiment describes a method of including a specific number of information in the S-SCH through five methods. This embodiment represents a specific number of information using at least one sequence. In this case, it is more preferable to combine at least two sequences to increase the number of information to include.

This embodiment uses a first sequence according to a scrambling code, a second sequence according to an orthogonal sequence modulation, and a modulation technique according to phase rotation on a constellation map. The modulation technique according to the phase rotation on the constellation may be referred to as 'M-PSK modulation'.

Specifically, the first sequence is preferably a sequence of CAZAC (constant amplitude & zero autocorrelation) series. For example, Zadoff-Chu sequences and the like are possible. Sequences of the CAZAC family are known as sequences with good correlation properties.

The CAZAC sequence generates various kinds of sequences according to the size of the sequence index, and each generated sequence is orthogonal to each other. Therefore, by adjusting the size of the sequence index, different L pieces of information may be represented.

Further, the second sequence is preferably a delayed CAZAC sequence. The delayed CAZAC sequence is a technique for generating a sequence by performing a cyclic delay in a time domain with respect to a specific sequence. The delayed CAZAC sequence may be referred to as a circular shifted CAZAC sequence.

Performing a cyclic delay for the sequence in the time domain results in phase rotation in the frequency domain. For example, there may be a sequence of 1, 1, 1 values in the frequency domain. In this case, if the sequence is cyclically delayed by the first delay value in the time domain, the sequence may be 1, 1exp (j2π / 3) and 1exp (j4π / 3) in the frequency domain. In addition, when the sequence is cyclically delayed by a second delay value in the time domain, the sequence may be 1, 1exp (j4π / 3) and 1exp (j2π / 3) in the frequency domain. In this case, a sequence of 1, 1, 1, a sequence of 1, 1exp (j2π / 3), 1exp (j4π / 3), and a sequence of 1, 1exp (j4π / 3), 1exp (j2π / 3) are orthogonal to each other. Therefore, three sequences may represent three different information.

The second sequence may be a Walsh code. Walsh codes can be generated by a hadamard matrix. For example, a sequence of length 4 Walsh codes is 1,1,1,1,1, -1,1, -1,1,1, -1, -1,1, -1, -1,1 There is. In this case, four pieces of information may be distinguished by four sequences. When the Walsh code is multiplied by S-SCH 1 or S-SCH 2, an S-SCH 1 or S-SCH 2 indicating four different pieces of information may be configured.

In summary, M pieces of different information may be represented through the second sequence.

N pieces of different information may be represented through a modulation scheme according to phase rotation on the constellation map. The modulation technique according to the phase rotation on the constellation is a technique of rotating the phase of a symbol on which constellation mapping has already been performed. That is, the modulation technique according to the phase rotation on the constellation is related to the rotated constellation to rotate the constellation. For example, in the conventional BPSK symbol, a BPSK symbol is located at a 0 degree point and a 180 degree point on a constellation map. N different pieces of information may be represented by rotating the phase of the BPSK symbol by a predetermined angle.

For example, if one wishes to further include four pieces of information (ie, two bits of information), one of four angles of 0 °, 45 °, 90 °, 135 ° is selected to rotate the phase. The receiving side may calculate how much additional phase is rotated from the phase of the conventional BPSK symbol to decode four different pieces of information.

Referring to the basic concept of the present embodiment described above with the formula.

Equation 3 relates to the case where the first sequence and the second sequence described above use both modulation techniques according to phase rotation on the constellation. Where l represents the index of the scramble code (eg, CAZAC sequence), m represents the index of the orthogonal code (eg, the delayed CAZAC sequence), and n represents the index according to phase rotation on the constellation. . In addition, i is an index for distinguishing S-SCH representing a specific number of information according to the present embodiment.

S-SCH is generated by combining the above-described Zadoff-Chu sequence, delayed CAZAC sequence, and modulation scheme according to phase rotation on constellation.

Hereinafter, five methods which further refine the above-described method will be described.

Method 1

Method 1 proposed in the present embodiment is to allocate a CAZAC sequence having a different sequence index to the S-SCH 1 and the S-SCH 2.

That is, some of the possible sequences are used for S-SCH 1, and the remaining sequences are used for S-SCH 2.

For example, if the sequence index exists from 0 to 63, the sequence ID that can be allocated to S-SCH 1 may be 0 to 31, and the sequence ID that may be allocated to S-SCH 2 may be 32 to 63. . In this case, since S-SCH 1 represents 32 different pieces of information and S-SCH 2 represents 32 different pieces of information, the total amount of information that can be displayed is 32 * 32 = 1024.

In addition, from the standpoint of the receiving end, the frame synchronization can be found by receiving and decoding the S-SCH. That is, when the index of the S-SCH is found to be 31 or less, the corresponding S-SCH may be known to be S-SCH 1, and if the index is 32 or more, it may be known that the S-SCH is S-SCH 2. Thus, frame synchronization can be found automatically.

In summary, when a sequence having 0 to 63 indexes is used according to Method 1, not only 1020 information can be displayed but also frame synchronization can be found.

Since the present invention is not limited to the number of S-SCHs, the method 1 may be applied even when four S-SCHs exist. That is, allocating 0 to 15 indices to the first S-SCH among four S-SCHs, assigning 16 to 31 indices to the second S-SCH, and 32 to 47 for the third S-SCH. Indexes may be allocated, and indexes 48 to 63 may be allocated to the fourth S-SCH. In this way, more than 1020 pieces of information can be displayed and frame sync can be found.

In the case of using the indices of 0 to 63 according to the above-described method 1, the information that can be represented is 1024 pieces. If it is necessary to display more than 1024 pieces of information, the above-described modulation scheme according to the phase rotation on the constellation may be used. In addition, it is possible to represent more kinds of information by performing a cyclic transposition on the sequence. In addition, in the case of the CAZAC sequence, more types of information may be represented by using a method of cutting a portion of the generated sequence after generating the sequence with a prime index.

When more than 1020 pieces of information are included in the S-SCH through Method 1, the receiving end decodes both S-SCH 1 and S-SCH 2 to obtain information included in the transmitting end.

An example 1 in which Method 1 is applied to a Hadamard sequence is described below. The length of the Hadamard sequence is assumed to be 64.

Example 1 of method 1

 Hadamard sequences are the same length and type of sequence. Therefore, if the length of the Hadamard sequence is 64, a total of 64 sequences are generated.

When using the S-SCH sequence in the frequency domain as a Hadamard sequence, the Hadamard sequence corresponding to the indices of 0 to 31 can be used as the S-SCH1 sequence. In addition, a Hadamard sequence corresponding to the indices of 32 to 63 can be used as the sequence of S-SCH2. At this time, the total amount of information included is 1024 (= 32 * 32).

Assume there are two NodeBs (base stations). At this time, a cell ID having a sequence index of NodeB 0 = S-SCH 1 index, S-SCH 2 index = 1,32, and NodeB 1 = 2,33 can be detected. When 1,32 is detected at the receiving end, a cell ID (or cell group ID) corresponding to NodeB 0 is detected, and when 2,33 is detected, it is determined that a cell ID (or cell group ID) of NodeB 1 is detected. do.

If 1,2 is detected, it is easy to see that an index of S-SCH1 or S-SCH2 is incorrectly detected. Candidates may be 32 or less indices, 32 or more indices, or 32 or more indices, or 32 or less indices if the detection is performed correctly at the receiving end. Therefore, the results of 1 and 2 can be removed and searched again.

This method may increase the amount of computation, but it is also possible to determine the cost function for possible combinations and to search through soft combining.

When the present Hadamard sequence is applied, a PAPR (Peak to Average Power Ratio) problem may occur. Therefore, it is more desirable to reduce the PAPR by performing scrambling in a sequence other than the Hadamard sequence.

When the Hadamard sequence is applied, performance must be degraded in a synchronous network because it must be detected through channel estimation and compensation through a cell-common P-SCH. This is a common feature of the Hadamard sequence. In a synchronous network, when a channel is estimated using a cell common P-SCH, a composite channel is estimated instead of the original channel.

Hereinafter, Example 2 in which Method 1 is applied to a CAZAC sequence will be described. The length of the CAZAC sequence (Hadamard sequence) is assumed to be 73.

Example 2 of method 1

3 is a view for explaining an example 2 of Method 1 of the present embodiment. The example of FIG. 3 uses a Zadoff-Chu sequence of length 73. When using the CAZAC sequence used in the present embodiment, the length is preferably a prime number. This is because when the sequence is generated by a few indexes due to the nature of the CAZAC sequence, more kinds of sequences are generated.

As shown in FIG. 3, a Zadoff-Chu sequence having an index of 0 to 35 is allocated to S-SCH 1. In addition, Zadoff-Chu sequence having an index of 36 to 71 is allocated to S-SCH 2.

In this case, the total amount of information included is 1296 (= 36 * 36).

Example 2 described above has a feature corresponding to example 1 using a Hadamard sequence, but has an advantage of not requiring separate data processing for PAPR reduction.

That is, in the case of using the Zadoff-Chu sequence, since the sequence is a CAZAC sequence, scrambling for PAPR reduction is not necessary. In addition, since Zadoff-Chu is less sensitive to channel estimation errors, it is less affected by the P-SCH, which is a cell common sequence.

Method 2

Method 2 relates to a method of assigning an index of a fixed pattern (index indicating a scrambling code) to S-SCH 1 and S-SCH 2. Method 1 relates to a method of classifying S-SCH 1 and S-SCH 2 according to an index. However, Method 2 relates to a method of distinguishing S-SCH 1 and S-SCH 2 through a pattern of two indexes, rather than distinguishing S-SCH 1 and S-SCH 2 by the index itself.

4 relates to a method of allocating a constant pattern index to S-SCH 1 and S-SCH 2 according to Method 2. FIG.

As shown in FIG. 4, the S-SCH 1 may be configured using a scrambling code (eg, a Zadoff-Chu sequence) generated according to the indices 0 to 71, and may be configured in the indices 0 to 71. The S-SCH 2 may be configured using the scrambling code generated accordingly. However, as shown, the indices assigned to S-SCH 1 and S-SCH 2 are contiguous with each other, and a smaller pattern is applied to the indexes assigned to S-SCH 1 than the indexes assigned to S-SCH 2. desirable.

Using the scrambling code (eg, the Zadoff-Chu sequence) generated according to the indices 0 to 71, 72 pieces of information can be represented.

Example 1 of Method 2 described below shows more information using an orthogonal code in addition to the scrambling code.

Example 1 of method 2

An example of representing L pieces of information according to a CAZAC sequence and M pieces of information according to a delayed CAZAC sequence will be described.

In the case of a delayed CAZAC sequence, a delay value may vary. For example, if the delay value is changed in three ways, when the delay is performed according to the first delay value in the time domain, signals of 1, 1, and 1 are generated in the frequency domain, and the delay is performed according to the second delay value in the time domain. In this case, a signal of 1, exp2π / 3, exp4π / 3 is generated in the frequency domain, and if a delay is performed according to a third delay value in the time domain, signals of 1, exp4π / 3, exp2π / 3 are generated in the frequency domain. Can be.

Using these three delay values, three kinds of distinguishable sequences are generated, and thus three types of information can be represented.

The delay value may be any value. For example, if the delay value is changed to six different values, when the delay is performed according to the first delay value in the time domain, signals of 1, 1, and 1 are generated in the frequency domain, and according to the second delay value in the time domain. If delay is performed, signals of 1, exp2π / 3, and exp4π / 3 are generated in the frequency domain, and if the delay is performed according to a third delay value in the time domain, signals of 1, exp4π / 3 and exp2π / 3 are generated in the frequency domain. Can be generated. In addition, when the delay is performed according to the fourth delay value in the time domain, signals of 1, expπ / 3, and exp2π / 3 are generated in the frequency domain, and when the delay is performed according to the fifth delay value in the time domain, 1 in the frequency domain. , signals of exp5π / 3 and exp4π / 3 are generated, and if a delay is performed according to a third delay value in the time domain, signals of 1, expπ, and 1 may be generated in the frequency domain.

If the delayed CAZAC sequence is used, the number of delay values is set to '8', and when 72 Zadoff-Chu sequences are used, a total of 576 (= 72 * 8) through S-SCH 1 or S-SCH 2 is used. Branch information can be expressed.

Using Example 1 of Method 2 or another example of Method 2 described below, the receiver may restore both S-SCH 1 and S-SCH 2 to obtain accurate information.

Method 2 must recover both S-SCH 1 and S-SCH 2 for accurate restoration, but the problem of ambiguity that can be caused in method 1 is eliminated, so performance can be improved compared to method 1.

As described above, according to the method 1, specific information is restored by a combination of sequence indices of S-SCH 1 and S-SCH 2. For example, when transmitting a cell ID in a synchronous network, cell A assigns sequence index '34' to S-SCH 1 and sequence index '36' to S-SCH 2, and cell B assigns S-SCH. A sequence index '35' may be assigned to 1 and a sequence index '37' may be assigned to S-SCH 2. In this case, the receiver may detect the sequence index '35' through S-SCH 1 and detect the sequence index '37' through S-SCH 2. In this case, an incorrect cell ID may be obtained at the receiving end through an incorrect sequence index.

In contrast, using method 2, when cell A assigns sequence index '34' to S-SCH 1, it assigns sequence index '35' to S-SCH 2, and cell B assigns sequence index 'to S-SCH 1'. If 36 'is allocated, sequence index' 37 'can be assigned to S-SCH 2. In this case, the receiver may detect the sequence index '34' through S-SCH 1 and detect the sequence index '37' through S-SCH 2. In this case, the receiving end may detect the sequence index {34, 35} or the sequence index {35, 36} according to the continuity of the index.

The amount of information to be included in the S-SCH may vary freely as required by a communication standard such as LTE. For example, in the conventional LTE standard, if '2' information is to be identified by antenna number information, 170 * 2 = 340 information should be included in the S-SCH. In addition, if '3' is needed as the antenna number information, 170 * 3 = 510 information should be included. In addition, if '4' is needed as the antenna number information, 170 * 4 = 680 pieces of information should be included.

In this case, using a Zadoff-Chu sequence identified according to 72 indexes and using 8 delay values, a total of 576 (= 72 * 8) pieces of information can be represented. In addition, when 10 delay values are used, a total of 720 (= 72 * 10) pieces of information may be represented.

Example 2 of method 2

Example 2 of Method 2 uses a scrambling code and a modulation technique according to the phase rotation on the constellation described above. For example, when a Zadoff-Chu sequence identified according to 72 indices is used and two pieces of information are represented through a modulation scheme according to phase rotation on constellations, a total of 144 (= 72 * 2) pieces of information may be represented. . In addition, when four pieces of information are represented through a modulation technique according to phase rotation on the constellation, a total of 288 (= 72 * 4) pieces of information may be represented.

When two pieces of information (one bit) or four pieces of information (two bits) are represented, two pieces of information can be represented by not rotating the phase and rotating the phase. There is an advantage in that coherent detection is possible.

Coherent detection is a detection that compares using only real or imaginary components among the metrics for a received signal after correcting a component distorted by a channel based on a phase of a reference signal or a separate reference signal. Say technique. Compared to non-coherent detection, which requires the use of both real and imaginary components of the complex signal, a 3dB gain occurs because the amount of noise is reduced by half.

In the present embodiment, detection is possible by comparing the real value after the channel compensation to which 1 bit is added. When 2 bits are added, the detection is possible by comparing each of the real value and the imaginary value.

Example 3 of method 2

Example 3 of Method 2 is an example of using the scrambling code and the Walsh code described above. For example, when a Zadoff-Chu sequence identified according to 72 indexes is used and 8 information is represented using a Walsh code of length 8, a total of 576 (= 72 * 8) information may be represented.

The number of information that can be represented through the S-SCH can be adjusted by using the examples 1, 2, 3, etc. of the method 2. When the S-SCH is configured according to the present embodiment, the standard required by the communication standard such as LTE Can be satisfied.

Method 3

Method 3 configures a sequence for S-SCH 1 and S-SCH 2 using the same sequence, but S-SCH 1 and S-SCH 2 are modulated by different numbers.

Example 1 of method 3

FIG. 5 relates to a method for configuring S-SCH 1 and S-SCH 2 according to Method 3. FIG.

As shown, scrambling codes (eg, Zadoff-Chu sequences) identified according to 72 indexes are used, and the orthogonal codes (eg, delayed CAZAC sequences or Walsh codes) are used. In this case, the indexes (indexes for identifying the scrambling code) assigned to the S-SCH 1 and the S-SCH 2 are the same. However, S-SCH 1 is modulated by '+1' and S-SCH is modulated by '-1'. That is, S-SCH 1 is constructed by using the result of multiplying the sequence of the scrambling code and the orthogonal code by '+1', and using the result of multiplying the sequence of the combination of the scrambling code and the orthogonal code by '-1'. It configures S-SCH 2.

It is also possible that the S-SCH 1 is modulated by '-1' and the S-SCH 2 is modulated by '+1'.

In the case of the method 3, after the same sequence (sequence generated by combining a scrambling code and an orthogonal code) is allocated to S-SCH 1 and S-SCH 2, modulation is performed by '+1' or '-1'. Therefore, the receiving side can restore data normally with only one of S-SCH 1 and S-SCH 2. Since the present embodiment provides cell group ID, antenna configuration information, and frame synchronization information through the S-SCH, information included in the S-SCH can be obtained through S-SCH 1 or S-SCH 2. have.

As shown in FIG. 5, S-SCH 1 and S-SCH 2 are generated through a scrambling code (eg, Zadoff-Chu sequence) having the same index, and delayed CAZAC sequence or same Walsh with the same delay value. Generated by code

For example, when using a CAZAC sequence using eight delay values or using a Walsh code of length 8, the amount of information included in S-SCH 1 or S-SCH 2 is 576 (= 72 * 8). Becomes In addition, S-SCH 1 and S-SCH 2 may be provided with information for frame sync by applying modulation by '+1' and '-1', respectively.

Example 2 of method 3

Example 2 of Method 3 uses a scrambling code (eg, Zadoff-Chu sequence) identified according to 72 indices, and uses a modulation technique according to the phase rotation on the constellation described above. . In this case, the indexes (indexes for identifying the scrambling code) assigned to the S-SCH 1 and the S-SCH 2 are the same. However, S-SCH 1 is modulated by '+1' and S-SCH is modulated by '-1'.

It is also possible that the S-SCH 1 is modulated by '-1' and the S-SCH 2 is modulated by '+1'.

In the case of Example 2 of Method 3, the receiving side can restore data normally only by using either S-SCH 1 or S-SCH 2.

S-SCH 1 and S-SCH 2 are generated through a scrambling code (eg, Zadoff-Chu sequence) having the same index, and are generated by a modulation technique according to phase rotation on the same constellation.

For example, when using a technique in which four types of phase rotation are performed, the amount of information included in S-SCH 1 or S-SCH 2 is 298 (= 72 * 4). In addition, S-SCH 1 and S-SCH 2 may be provided with information for frame sync by applying modulation by '+1' and '-1', respectively.

Method 4

Method 4 proposes to simultaneously use the above-described delayed CAZAC sequence and modulation scheme according to phase rotation on constellation. In the case of the delayed CAZAC sequence, various numbers of information may be represented according to different delay values. In addition, in the modulation scheme according to the phase rotation on the constellation, various numbers of information are represented by a method of rotating the phase of a conventional symbol (for example, QPSK, 16QAM, etc.). More information may be indicated by simultaneously using the above-described delayed CAZAC sequence and a modulation technique according to phase rotation on the constellation.

Method 4 may use the example of FIG. 3. That is, as shown in FIG. 3, the Zadoff-Chu sequence at indexes 0 to 35 is allocated to S-SCH 1, and the Zadoff-Chu sequence at indexes 36 to 71 is allocated to S-SCH 2. In this case, a cyclic delay may be applied in the time domain, and a desired number of information may be represented by using a modulation technique according to phase rotation on the constellation.

The receiver may check the information included in the S-SCH by reconstructing the S-SCH 1 and the S-SCH 2.

Method 5

Method 5 proposes to perform modulation using '+1' or '-1' for the proposed methods. That is, S-SCH 1 generated by the above-described methods 1, 2, and 4 is modulated by '+1 (or -1)', and S-SCH 2 by '-1 (or +1)'. It is suggested to perform modulation.

As described above, it is modulated by '+1' or '-1' and used as information for frame synchronization.

FIG. 6 is a diagram illustrating a method of performing modulation by '+1' or '-1' on the result of Method 2. FIG. As shown, S-SCH 1 and S-SCH 2 are assigned an index of a predetermined pattern. That is, assign contiguous indexes, assign smaller (or larger) indexes to S-SCH 1 and assign larger (or smaller) indexes to S-SCH 2. In addition, S-SCH 1 and S-SCH 2 are modulated by '+1' or '-1', respectively.

The above five methods can be applied to channels other than the S-SCH. That is, it may be applied to the P-SCH. 7 shows an example in which Method 2 is applied to a P-SCH. As shown in FIG. 7, the above-described method 2 is still applied, but desired information may be delivered to the P-SCH. 8 is an example in which Method 3 is applied to a P-SCH.

As shown, the methods 1 to 5 may be applied to a channel such as a P-SCH.

Second embodiment

The second embodiment to be described below proposes a method of transmitting control information about a hopping option for a downlink reference signal. The second embodiment is preferably combined with the methods 1 to 5 of the first embodiment described above. That is, it is possible to add control information regarding the hopping option through the P-SCH or the S-SCH configured according to the first embodiment described above.

The hopping option described above will now be described.

The hopping option relates to frequency hopping of a downlink reference signal. The transmitting end may perform the leap of the reference signal according to a frequency band managed by itself, a type of service (for example, an MBMS service or a unicast service), a cell, and the like. For example, the transmitting end may leap and transmit a reference signal in a first pattern in a first cell, hop in a second pattern in a second cell, and transmit a hop in a third pattern in a third cell. .

All sub-frames within the cell or carrier are preferably hopping or no hopping for the downlink reference signal. In this case, the unit of hopping is a subframe.

In this case, the receiving end preferably receives information regarding whether the transmitting end performs frequency hopping on the reference signal. Information about whether to perform the frequency hopping is a hopping option.

The reference signal is a signal called a pilot signal or the like and is a signal already known to the transmitting and receiving end. The channel estimation may be performed through the reference signal.

Hereinafter, signaling for the hopping option will be described.

Since the downlink reference signal provides a phase reference necessary for demodulating a control channel or a data channel (traffic channel), the receiving end needs to know whether hopping. If you don't know if you're hopping, you have to perform blind detection, which increases complexity.

The second embodiment proposes signaling for the hopping option. The second embodiment proposes a method in which a hopping option is detected at a stage in which a receiving end (eg, a UE) does not need to use a reference signal as a phase reference.

More specifically, the second embodiment proposes a method in which a hopping option is detected in a cell search step.

The steps for the current cell search are as follows.

First, timing synchronization acquisition is performed through the P-SCH, the frequency offset is estimated and compensated, and the cell ID is detected within the cell group ID.

Secondly, the cell group ID is detected through the S-SCH, frame boundary acquisition is performed, and other information is received.

Third, cell ID confirmation is performed through the reference signal or other information is confirmed.

Fourthly, the primary broadcast channel (p-BCH) is demodulated to obtain basic system parameters.

The following four methods may be used to detect the hopping option in the cell search step described above.

Firstly, a method of transmitting a hopping option via p-BCH is possible. However, this method can cause the following problems.

Since p-BCH is basically modulated by a basic modulation unit such as QPSK, a reference signal for coherent demodulation is required. Thus, this method raises the problem that the reference signal for the p-BCH should not be hopped.

Secondly, a method of transmitting a hopping option through a reference signal is possible. However, this method has a problem of deterioration in performance.

Since the reference signal is inserted in three subcarrier intervals in the frequency domain, the reference signal is allocated outside the coherent BW period. Since the receiver cannot know the transmission band of the receiver until it decodes p-BCH, it should use only 1.25MHz band. In this case, since only a reference signal in one subframe (48 in this case) can be used, performance is degraded as compared with the other method proposed below.

Third, a method of transmitting a hopping option through the P-SCH is possible.

The basic premise of the current LTE specification is to use three Primary Synchronization Codes (PSCs). To use three PSCs, cell planning must be performed. Cell planning refers to a procedure for allocating PSCs to a cell or sector in order for a communication system to operate efficiently.

In the case of supporting a plurality of PSCs through the P-SCH, a problem of increasing complexity at the receiving end may occur. In the case of the correlation operation performed for P-SCH demodulation, unlike the correlation operation for the S-SCH channel, the complexity increases rapidly when various information is included in the P-SCH. If there are three types of PSCs, adding a hopping option to the P-SCH further increases the complexity. Therefore, it is preferable not to include information such as a hopping option in the P-SCH.

Meanwhile, a hopping option may be added to the P-SCH using a method of rotating the constellation of the P-SCH, that is, the M-PSK modulation method.

Fourth, a method of transmitting a hopping option through the S-SCH is possible.

As described in the first embodiment, it is possible to add a sequence index to the S-SCH, or add another FDM / TDM (when the S-SCH is 2 symbols or more) / CDM. That is, information can be added through various sequence indexes. In addition, various information may be added through sequence indexes classified according to different frequencies / times / codes. Meanwhile, as described in the first embodiment, it is possible to add a hopping option of 1 bit through M-PSK modulation.

Conventional S-SCH detection techniques must perform blind detection for short / long cyclic prefixes. That is, two FFT operations must be performed.

However, by performing M-PSK modulation according to the present embodiment, it is possible to obtain 1 bit (ie, hopping option) without increasing the complexity. In other words, applying M-PSK modulation makes it possible to transmit one bit of information without increasing complexity and degrading performance.

As described above, the hopping option is preferably transmitted through the S-SCH or P-SCH proposed in the first embodiment.

Hereinafter, a method of transmitting the hopping option through the S-SCH will be described. More specifically, a method of transmitting the hopping option through the method 3 of the first embodiment will be described.

Method 3 of the first embodiment transmits one bit of additional information by multiplying '+1' or '-1', as also shown in FIG. Since multiplying '+1' or '-1' is the same as causing phase rotation on constellation, Method 3 of the first embodiment performs the above-described M-PSK modulation. In the example of FIG. 5, frame synchronization may be obtained through M-PSK modulation.

Hereinafter, the second embodiment proposes to transmit only a hopping option, transmit information for frame synchronization, or transmit both hopping option and information for frame synchronization through M-PSK modulation applied to the S-SCH.

Hereinafter, an example of transmitting both hopping options and information for frame synchronization will be described. It is assumed that the hopping option and the information for frame synchronization are 1 bit of information (total of 2 bits in total). The hopping option or information for frame synchronization may be a specific size bit.

FIG. 9 is a block diagram illustrating an example in which both a hopping option and information on frame synchronization are included according to the second embodiment.

9 assigns a sequence index to S-SCH 1 and S-SCH 2 similarly to FIG. 5. The sequence index is preferably a sequence index that identifies a Zadoff-Chu sequence. In addition, it is preferable that the delayed CAZAC sequence technique is applied to S-SCH 1 and S-SCH 2 to transmit additional information.

Unlike FIG. 5, the example of FIG. 9 further provides information on a hopping option, and thus, it is preferable to represent two pieces of information through M-PSK modulation. For example, when hopping is deactivated as in the first case 901 of FIG. 9, M-PSK modulation is performed using '+1' and '-1', and '+ j' when hopping is activated. M-PSK modulation may be performed by using '-j'. Alternatively, as in the second case 902 of FIG. 9, when hopping is deactivated, M-PSK modulation is performed using '1' and '+1', and '-j' when hopping is activated. M-PSK modulation may be performed using 'and' + j '.

S-SCH 1 and S-SCH 2 according to the second embodiment provide information about a frame boundary, that is, information for frame synchronization. It also provides information about hopping options that indicate a hopping pattern.

9 illustrates a method of transmitting information about a hopping option and / or frame synchronization using an S-SCH. As described above, since the second embodiment is based on the first embodiment, the information on the hopping option and / or frame synchronization can be transmitted through the P-SCH in addition to the S-SCH. In this case, instead of S-SCH 1 and S-SCH 2 used in the example of FIG. 9, P-SCH 1 and P-SCH 2 may be used to transmit information about a hopping option and / or frame synchronization.

Hereinafter, an example of the various methods of M-PSK modulation mentioned above is demonstrated.

로 표시될 수 있다. 즉, 주파수 성분 k에 따라 동일하거나 서로 상이한 값을 이용하여 위상 성분을 회전시킬 수 있다. 예를 들어, 무선 프레임에 포함되는 S-SCH 1 시퀀스는 다수의 부 반송파를 통해 송신되는데 이 경우, '+1' 또는 '+j' 등의 하나의 값으로 위상 성분을 회전시킬 수 있다. 또한, 특정한 부 반송파에 대해서는 위상 성분을 회전시키고, 나머지 부 반송파에 대해서는 위상 성분을 회전시키지 않을 수가 있다. 또한, 특정 시퀀스 엘리먼트에 대해서만 위상 성분을 회전시킬 수 있다. As shown in Equation 3, M-PSK modulation is

It may be represented as. That is, the phase component can be rotated using the same or different values according to the frequency component k. For example, the S-SCH 1 sequence included in the radio frame is transmitted through a plurality of subcarriers. In this case, the phase component may be rotated by one value such as '+1' or '+ j'. In addition, the phase component may be rotated for a specific subcarrier, and the phase component may not be rotated for the remaining subcarriers. It is also possible to rotate the phase component only for certain sequence elements.

The M-PSK modulation proposed in this embodiment can be used for various channels. Hereinafter, the result of performing M-PSK modulation on the S-SCH will be described.

10A to 10F relate to an example of rotating a phase component using different phase rotation components for a plurality of subcarriers.

It is preferable that the technique of the above-described CAZAC sequence or delayed CAZAC sequence is already applied to the S-SCH shown in the example of FIGS. 10A to 10F.

In addition, S-SCH 1 and S-SCH 2 illustrated in the example of FIGS. 10A to 10F may be temporally adjacent sequences or spaced apart sequences.

FIG. 10A illustrates a result of performing M-PSK modulation with one phase rotation component on S-SCH 1 and S-SCH 2. FIG. As shown, one value (eg '+1') or multiple values (eg '+1' for some components and '-j' for the remaining components for all frequency components Can be rotated). In the example of FIG. 10A, the phases of all frequency components are rotated, so a separate phase reference is required.

For example, if S-SCH 1 and S-SCH 2 of FIG. 10A correspond to 72 subcarriers, the S-SCH 1 is a 72-length sequence generated by one seed value (eg, For example, the above-described CAZAC sequence, Jadodorf-Chu sequence, Frank sequence), and the S-SCH 2 may correspond to the 72-length sequence generated by another seed value.

FIG. 10B illustrates a result of performing M-PSK modulation on S-SCH 1 and not performing M-PSK modulation on S-SCH 2. FIG. The example of FIG. 10B has the advantage that there is no need to provide a separate phase reference since M-PSK modulation is not performed for some sequences.

Region 10 of FIG. 10B may be a 72-length sequence generated by a particular first seed value, and region 20 of FIG. 10B may be a 72-length sequence generated by a particular second seed value. This feature can be equally applied to FIGS. 10C to 11D.

In addition, M-PSK modulation may not be performed in region 10 of FIG. 10B, and M-PSK modulation may be performed in region 20. This feature can be equally applied to FIGS. 10C to 11D.

10C is a diagram illustrating that a sequence that is not performed in a sequence in which M-PSK modulation is performed may be freely determined.

10D is another example according to the present embodiment. As shown, M-PSK modulation is performed on some frequency components of S-SCH 1 and some frequency components of S-SCH 2, and M-PSK modulation is not performed on the remaining components. That is, M-PSK modulation is performed on the 1001, 1003, 1005, and 1006 components. On the other hand, M-PSK modulation is not performed on the 1002 and 1004 components. In this case, the phases 1001, 1003, 1005, and 1006 may all be rotated by one phase rotation component (eg, '+ j'), and may be rotated by several phase components. That is, the phases of the 1001 and 1003 components may be rotated by '-1', and the phases of the 1005 and 1006 components may be rotated by '+ j'.

10E to 10F are still another example according to the present embodiment.

의 값을 자유롭게 조절하여 다양한 M-PSK 변조를 수행할 수 있다. As shown,

By freely adjusting the value of can be performed a variety of M-PSK modulation.

11A to 11C show another example according to the present embodiment.

As shown in FIG. 11A, M-PSK modulation may be performed on all components except for a portion of S-SCH 1. In addition, as illustrated in FIG. 11B, M-PSK modulation may be performed on the remaining components except for some components of S-SCH 1 and S-SCH 2.

In addition, M-PSK modulation may be performed as in the example of FIG. 11C.

11D illustrates an example of performing different types of information through M-PSK modulation.

As shown, M-PSK representing M1 information is applied to some frequency components 10, and M-PSK representing M2 information is applied to some other frequency components 30. M-PSK may not be applied to the remaining components 20.

The M1 information or M2 information may be various information including information for frame synchronization or hopping information.

In the above example, the position where M-PSK modulation is performed and the position where M-PSK modulation is not performed may be changed.

Those skilled in the art through the above description can be seen that various changes and modifications can be made without departing from the spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

When configuring a channel for synchronization according to the present invention, it is possible to include a variety of information in the channel for synchronization. Through this, various information may be provided to the receiver to help in acquiring synchronization.

Claims (9)

In the method for transmitting information using a sequence, Generating a sequence for data or control signal transmission; Rotating at least one component of the sequence; And Transmitting the rotated sequence to a receiving end, The at least one phase rotation component of the generated sequence is an arbitrary information value A method of transmitting information using a sequence. In the method for transmitting information using a sequence, Generating a sequence corresponding to the channel for synchronization using two or more codes including orthogonal code and scrambling code; Rotating a phase using at least one phase rotation component with respect to at least one first component of the generated sequence; Including but not limited to: The at least one phase rotation component corresponds to at least one of information for frame synchronization and information about a pattern of frequency hopping performed at the transmitting end. A method of transmitting information using a sequence. The method of claim 2, The information about the pattern of the frequency hopping, Control information about the frequency hopping of the downlink reference signal, A method of transmitting information using a sequence. The method of claim 2, The orthogonal code is generated by a cyclic shift constant shift constant amplitude zero auto-correlation (CAZAC) sequence. A method of transmitting information using a sequence. The method of claim 2, The scrambling code is generated by a constant amplitude zero auto-correlation (CAZAC) sequence. A method of transmitting information using a sequence. The method of claim 2, The scrambling code is generated by a Zadoff-Chu sequence. A method of transmitting information using a sequence. The method of claim 2, The channel for synchronization may be at least one of a first floating channel (Secondary Synchronous Channel 1: S-SCH 1) and a second floating channel (Secondary Synchronous Channel 2: S-SCH 2). A method of transmitting information using a sequence. The method of claim 7, wherein Phase rotation is performed on the first component of the first and second floater channels, and phase rotation is not performed on the remaining second component. A method of transmitting information using a sequence. The method of claim 2, The channel for synchronization may be at least one of a Primary Synchronous Channel (P-SCH 1) and a Second Synchronous Channel (P-SCH 2). A method of transmitting information using a sequence.

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