WO2008130206A1

WO2008130206A1 - Method for generating sequence and method for transmitting signal based on the sequence in mobile communication system

Info

Publication number: WO2008130206A1
Application number: PCT/KR2008/002338
Authority: WO
Inventors: Seung Hee Han; Min Seok Noh; Yeong Hyeon Kwon; Hyun Woo Lee; Dong Cheol Kim; Jin Sam Kwak
Original assignee: Lg Electronics Inc.
Priority date: 2007-04-24
Filing date: 2008-04-24
Publication date: 2008-10-30

Abstract

A method for generating a sequence and transmitting a sequence-based signal are disclosed. According to the sequence generation method, each of at least two sequences is divided into a real part and an imaginary part, such that the resultant sequence is configured. As a method for transmitting the sequence-based channel signal, the sequence generated by the above sequence generation method may be mapped to a channel, and is then transmitted. Otherwise, at least two sequences are combined according to an interleaved or localized structure, and are then mapped to the channel. In this case, both inphase (I) and quadrature (Q) components of the channel are used for this channel mapping, such that the channel mapping result may be transmitted.

Description

[DESCRIPTION] [Invention Title]

METHOD FOR GENERATING SEQUENCE AND METHOD FOR TRANSMITTING SIGNAL BASED ON THE SEQUENCE IN MOBILE COMMUNICATION SYSTEM

[Technical Field]

The present invention relates to a mobile communication system, and more particularly to a method for generating a sequence for use in a mobile communication system, and a sequence-based signal transmission method.

[Background Art]

A method for generating two or more sequence sets capable of being applied to a specific channel of a communication system, and a sequence generation method for the above method will hereinafter be described in detail.

FIG. 1 is a conceptual diagram illustrating a method for generating a two- layered sequence.

In order to increase an amount of information to be transmitted within limited resources, the two-layered sequence as shown in Fig. 1 can be used. Generally, the two-layered sequence is a combination of a scramble sequence and an orthogonal sequence. In other words, the two-layered sequence may be composed of a vector product of a scramble sequence and an orthogonal sequence as shown in FIG. In this way, although the two-layered sequence is able to transmit a large amount of information, it requests an excessive number of calculation times from a reception end. For example, it is assumed that a total of sequence length is "N", an amount of information from the scramble sequence is "Msc", and an amount of information from the orthogonal sequence is "Mor".

Under the aforementioned assumption, the total amount of information capable of being transmitted is denoted by "Msc*Mor". However, in order to allow the reception end to detect the information whose amount is "Msc*Mor", a total of correlation calculation times "Msc*Mor" are required. In more detail, provided that "N" is 64 (N=64), the scramble sequence is a

Zadoff-Chu (ZC) sequence (Msc=32), and the orthogonal sequence is a Hadamard sequence (Mor=54), a total amount of available information is denoted by 32*64=2048. In this case, a total of 2048 correlation calculations are requested.

[Disclosure] [ Technical Problem ]

Accordingly, the present invention is directed to a method for generating a sequence for use in a mobile communication system, and a sequence-based signal transmission method that substantially obviate one or more problems due to limitations and disadvantages of the related art. An object of the present invention is to provide a sequence generation method for allowing a reception end to easily detect a desired signal, and a method for transmitting a channel signal based on a sequence. Another object of the present invention is to provide a sequence generation method which reduces the number of calculations of a transmission/reception end, and increases an amount of transmission (Tx) information of the transmission/reception end, and a method for transmitting a channel signal based on a sequence.

[Technical Solution]

To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a signal transmission method based on a sequence in a communication system comprising: selecting at least one sequence; and mapping the at least one selected sequence to at least one of an inphase (I) component and a quadrature (Q) component, and transmitting the mapping resultant signal.

Preferably, the signal transmission method according to claim 1, wherein some elements of each of the at least one sequence are mapped to the inphase (I) component, and the remaining elements of each of the at least one sequence are mapped to the quadrature (Q) component.

Preferably, the signal transmission method according to claim 1, wherein some elements of the at least one sequence are mapped to the inphase (I) component, and other elements of the at least one sequence are mapped to the quadrature (Q) component. Preferably, the selected sequences may be a first sequence and a second sequence. If each of the first and second sequences is a binary sequence, the first sequence is configured in the form of a real value of the above sequence, and the second sequence is configured in the form of the sum of complex numbers composed of an imaginary value of the above sequence.

If each of the first and second sequences is a complex sequence, the real value of the first sequence or the imaginary value of the second sequence is composed of the real value of the above sequence, and the imaginary value of the first sequence and the real value of the second sequence may be equal to the sequence having the sum of complex numbers composed of the imaginary value of the above sequence.

Preferably, at least one of the selected sequences is configured when a third sequence is multiplied by the first sequence and a fourth sequence is multiplied by the second sequence. In this case, the third sequence may be equal to the fourth sequence.

In this case, it is considered that the third sequence is multiplied by the sum of complex numbers of the first and second sequences. In this case, the third sequence may be the scramble sequence.

Preferably, the first sequence and the second sequence are either homogeneous sequences or heterogeneous sequences.

Preferably, the at least one of the selected sequences is mapped according to a sequence combination scheme when it is mapped to the channel.

Preferably, the sequence combination scheme maps a first sequence and a second sequence to the channel on a sub-carrier axis according to a localized method. Preferably, the sequence combination scheme maps elements of a first sequence and elements of a second sequence to the channel on a sub-carrier axis according to an interleaved method.

In another aspect of the present invention, there is provided a sequence generation method comprising: selecting a first sequence and a second sequence; and generating a sequence by adding the first sequence and the second sequence, in which the second sequence is multiplied by an imaginary unit (j) (wherein a square of the imaginary unit (j) is "-1").

Preferably, the sequence is configured when a third sequence is multiplied by the first sequence and a fourth sequence is multiplied by the second sequence, or is configured when the third sequence is multiplied by the sum of complex numbers of the first and second sequences.

Preferably, the at least one of the first sequence, the second sequence, and the third sequence is a complex signal including at least one of a real value and an imaginary value.

Preferably, the at least one of the first sequence, the second sequence, and the third sequence is either one of a scramble sequence and a quadrature sequence (or an orthogonal sequence).

In another aspect of the present invention, there is provided a signal transmission method based on a sequence in a mobile communication system comprising: selecting a sequence; and transmitting a signal using the selected sequence and both an inphase (I) channel and a quadrature (Q) channel of the channel. In another aspect of the present invention, there is provided a signal transmission method for a mobile communication system comprising: selecting a sequence; and transmitting a signal using the selected sequence, wherein the sequence includes at least two different sequences. The real value and the imaginary value of the sequence are composed of different sequences. In another aspect of the present invention, there is provided a signal generation method for a communication system comprising: generating a sequence using at least one sequence, in which at least one sequence includes a real value and an imaginary value, such that the sequence can be generated. In another aspect of the present invention, there is provided a signal transmission method in a communication system including several cells comprising: employing at least one of a sequence generation method, which is different in each cell, and a sequence-based channel signal transmission method, wherein the sequence generation method allows at least two sequences with a real value and an imaginary value, thereby generating each sequence, and the sequence-based channel signal transmission method divides at least one sequence into an inphase (I) component and a quadrature (Q) component of the channel, maps the at least one sequence to the I component and the Q component, and transmits the mapping result.

Preferably, the individual elements of the sequence are a complex signal including at least one of a real value and an imaginary value.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

[Advantageous Effects]

By the following embodiments of the present invention, a desired signal can be more easily detected from the reception end. As a result, the number of calculation times of the transmission/reception ends can be reduced, resulting in the increase of an amount of Tx information.

I Description of Drawings]

The accompanying drawings, which are included to provide a further understanding of the invention, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention. In the drawings:

FIG. 1 is a conceptual diagram illustrating a method for generating a two- layered sequence; FIG. 2 is a conceptual diagram illustrating a method for generating a sequence according to one embodiment of the present invention;

FIG. 3 is a conceptual diagram illustrating an example of a sequence combination method according to the present invention;

FIG. 4 is a structural diagram illustrating a 10ms radio frame structure proposed by the 3GPP LTE according to the present invention;

FIG. 5 is a structural diagram illustrating a exemplary method for combining sequences for SSC(Secondary Synchronization code) of 3GPP LTE according to the present invention;

FIG. 6 is a conceptual diagram illustrating a method for mapping the S-SCH signal using at least two sequences according to the present invention; FIG. 7 is a conceptual diagram illustrating a method for mapping the S-SCH signal using at least two sequences according to one embodiment of the present invention;

FIG. 8 is a conceptual diagram illustrating a method for mapping the S-SCH signal using at least two sequences according to the present invention;

FIG. 9 shows PDF graphs of PAPR and CM when the Golay sequence modulated with the 64-length Hadamard sequence is applied to a single code;

FIGS. 10 to 14 show the simulation resultant graphs of the embodiments shown in FIGS. 6 to7 according to the present invention; and FIGS . 15 ~ 18 show PDF graphs of PAPR and CM acquired when the Golay sequence modulated with the Hadamard sequence is used as the SSC according to a conventional interleaved mapping scheme, a localized mapping scheme, a rotational interleaved mapping scheme, and a rotational localized mapping scheme.

[Best Mode] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

The following embodiment(s) transmits a channel signal using at least one sequence, and allows a reception end to transmit at least two component signals capable of being discriminated by the reception end. For example, a channel may be divided into an Inphase (I) channel and a Quadrature (Q) channel at a channel mapping time, and be mapped into channels. In this case, individual elements of the In-phase-sequence element and the Quadrature-sequence element can be determined in various ways.

At least two sequences are combined when the final sequence mapped to the channel is constructed. One of the sequences is composed of a real value (or a real part), and the other one is composed of an imaginary value (or an imaginary part), such that the at least two sequences are divided into Inphase (I) components and Quadrature (Q) components. I-components and Q-components are mapped to the channel. In this case, if the sequence is divided into the I-component and the Q- component, and the I-component and the Q-component are mapped to the channel, or if at least two sequences are combined with each other, individual sequences may be configured according to an interleaved or localized method.

For this purpose, a mobile communication system for use in the following embodiments of the present invention will hereinafter be described. Specifically, a sequence for use in a multi-carrier system (e.g., an OFDM system, an OFDMA system, and a 3GPP LTE system, or an IEEE 802.16e/m system) will hereinafter be described in detail.

In recent times, as the demand of high-speed data transmission rapidly increases, the Orthogonal Frequency Division Multiplexing (OFDM) scheme is more advantageous to this high-speed transmission, so that the OFDM scheme is used as a transmission scheme for use in a variety of high-speed communication systems. The OFDM (Orthogonal Frequency Division Multiplexing) scheme will hereinafter be described. According to the basic principles of the OFDM scheme, the OFDM scheme divides a high-rate data stream into many slow-rate data streams, and simultaneously transmits the slow-rate data streams via many carriers. Each of the carriers is called a sub-carrier.

The orthogonality exists between many carriers of the OFDM scheme. Accordingly, although frequency components of the carrier are overlapped with each other, the overlapped frequency components can be detected by a reception end. A high-rate data stream is converted to a low-rate data stream by a serial to parallel (SP) converter. The individual sub-carriers are multiplied by the parallel data streams, the individual data streams are added to the multiplied result, and the added result is transmitted to the reception end. The OFDMA scheme is a multiple access method for allowing the OFDMA scheme to allocate specific subcarriers among the total subcarriers for a multi-user according to a transmission rate required by the multi-user.

The above-mentioned OFDM system has a disadvantage in that either a

Peak-to-Average-Power Ratio (PAPR) or a Cubic Metric (CM) of a transmission (Tx) signal is very high. As frequency domain signals are Inverse Fast Fourier Transformed to produce corresponding time domains signals (multi-carrier), and the time domain signals are added to each other, the amplitude of an OFDM signal may be denoted by a sum of the time domain signals. If individual phases of the time domain signals are equal to each other, the OFDM signal has a very high PAPR or CM due to the occurrence of a signal of a high maximum value such as an impulse. The OFDM-based Tx signal reduces the efficiency of a high-power linear amplifier, and allows the high-power amplifier to be driven in a non-linear area, resulting in the occurrence of signal distortion. In the meantime, a channel for use in the 3rd Generation Partnership Project (3 GPP) Long Term Evolution (LTE) system and a sequence for use in the above channel will hereinafter be described in detail.

Generally, the highest priority matter for allowing a user equipment (UE) to communicate with a Node-B or base station is that the user equipment (UE) establishes synchronization with the Node-B over a synchronous (SCH) channel and then searches for a cell. This SCH channel may have a hierarchical structure, such that it may be classified into a primary-SCH (P-SCH) channel and a secondary-SCH (S-SCH) channel. The above-mentioned process in which the UE establishes synchronization with the Node-B and acquires a cell ID of the UE is called a cell search process. Generally, the cell search process is classified into an initial cell search step and a neighbor cell search step. The initial cell search step is performed when the initial UE is powered on. The neighbor cell search step is performed when a UE in connection-mode or a UE in idle-mode searches for a neighboring Node-B.

Preferably, the synchronous channel (SCH) for use in the communication system (e.g., an OFDM or SC-FDMA system) capable of using several orthogonal sub-carriers may satisfy the following first to fourth conditions.

According to the first condition, the above-mentioned communication system must have superior time-domain auto-correlation characteristics of a sequence constituting the SCH, such that it can detect superior performances at a reception end.

According to the second condition, the above-mentioned communication system must have a low complexity according to synchronization detection. According to the third condition, the above-mentioned communication system must have a low PAPR value or a low CM (Cubic Metric) value.

According to the fourth condition, if the synchronous channel is used for channel estimation, it is preferable that a frequency response of the SCH channel may be constant. In other words, in light of the channel estimation, it is well known in the art that the best channel estimation performance is accomplished when a response is flat in the frequency domain.

For the convenience of description and better understanding of the present invention, although the above-mentioned communication system has been described on the basis of a synchronous channel (e.g., S-SCH) of the 3GPP LTE system, it can also be equally applied to sequence-based channels (e.g., a random access channel

(RACH), a uplink/downlink (DL/UL) reference signal, and a uplink/downlink

(DL/UL) control channel). For example, the DL/UL control channel may be an

ACK/NACK channel, a CQI channel, or a scheduling request (SR) channel. The channels described in this document may not be limited to general communication channels, and may include any signal such as the above-mentioned signal.

In other words, the following embodiments of the present invention may be applied to not only transmission of a channel signal but also transmission of various signal types. The following description will use a binary-based sequence. In the case of correlation calculation, the binary sequence can be implemented with the sum of complex numbers, such that the present invention is advantageous to calculation complexity. Needless to say, it should be noted that the sequence based on a complex number may also be applied to the following embodiments. Next, a method for generating a sequence capable of using both an I- component and a Q-component of a channel according to one embodiment of the present invention will hereinafter be described in detail.

According to a method for transmitting the sequence-based channel signal using a communication system of the present invention, a channel signal is transmitted on the basis of the final sequence composed of the sum of at least two sequence complex numbers.

According to this embodiment, a first sequence and a second sequence are used to generate another sequence capable of being transmitted through a channel (e.g., the S-SCH signal). An exemplary method for generating the final sequence using the first and second sequences is represented by the following equation 1 : [Equation 1 ]

In Equation 1, Sl(n) denotes a first sequence, S2(n) denotes a second sequence, and S(n) denotes the final sequence acquired by the combination of the first sequence and the second sequence. In this case, "n" is an index of a sequence element. If a total length of the index is N, "n" may be set to an arbitrary integer number from among 0 ~ N-I. The sequence S(n) may be composed of a first sequence Sl(n) and a second sequence S2(n). The first sequence Sl(n) is composed of a real value, and the second sequence S2(n) is composed of an imaginary value.

In this case, the final sequence S(n), the first sequence Sl(n), and the second sequence

S2(n) are complex signals. Needless to say, each of the final sequence S(n), the first sequence Sl(n), and the second sequence S2(n) may also be composed of an imaginary or real signal.

In order to reduce the PAPR or CM value or to randomize interference between cells, the present invention may apply a scramble code. The following equation 2 shows an example for additionally applying a scramble sequence to the sequence generated by Equation 1 : [Equation 2]

S(H)=[ S₁ (H^j S ₂(n) }E(H)

In Equation 2, Sl(n), S2(n), and S(n) are equal to those of Equation 1. That is, Sl(n) is a first sequence, S2(n) is a second sequence, and S(n) is the final sequence acquired by the combination of the first sequence and the second sequence. Differently from Equation 1, E(n) denotes an additionally-applied scramble sequence. In case of additionally applying scramble codes in order to reduce the PAPR value or the CM value or to randomize interference between cells, the same scramble code may be applied to each of Sl(n) and S2(n) as shown in Equation 2. In this case, El(n) can also be modulated even when the sequences Sl(n) and S2(n) are scrambled by the same or different scramble sequence. The following equation 3 shows an example for scrambling each of S 1 (n) and S2(n) with scramble sequences, which is different from Equation 2: [Equation 3]

S(YI)= S ₁ (VI) E M⁺J S₂(VI) E₂(VI)

In Equation 3, Sl(n), S2(n), and S(n) are equal to those of Equation 1. Each of El(n) and E2(n) denotes an additionally-applied scramble sequence. As described above, El(n) and E2(n) may be equal to each other or El(n) may be have the same sequence as that of E2(n). If El(n) and E2(n) are equal to each other, Equation 3 may be equal to the above Equation 2.

In case of performing normalization in consideration of actual transmission, the following equation 4 can be acquired. For the convenience of description, it is assumed that the same scramble sequence be used. [Equation 4]

In Equation 4, Sl(n), S2(n), and S(n) are equal to those of Equation 1. In the same manner as in Equation 2, E(n) is an additionally-applied scramble sequence. Specifically, an exemplary normalization is executed on the assumption that the scramble sequence E(n) has the power of 1.

FIG. 2 is a conceptual diagram illustrating a method for generating a sequence according to one embodiment of the present invention. A method for constructing a final sequence by combining the first sequence

Sl(n) with the second sequence S2(n) in the form of a complex number will hereinafter be described with reference to FIG. 2. In this case, the first sequence Sl(n) may be equal to the second sequence S2(n), or may also be different from the second sequence S2(n). For the convenience of description and better understanding of the present invention, it is assumed that the present invention uses the same sequence. Specifically, the present invention assumes that the Hadamard sequence is used for a first sequence Sl(n) and a second sequence S2(n). As described above, it is assumed that the present invention uses a binary-based sequence.

A first sequence Sl(n) having the length of N may be configured as shown in FIG. 3. In other words, the first sequence Sl(n) may be configured in the form of Sl(O), Sl(I), S 1(2), S 1(3), ..., Sl(N-4), Sl(N-3), Sl(N-2), Sl(N-I). In this way, the second sequence S2(n) may also be configured in the form of S2(0), S2(l), S2(2),

S2(3), ... , S2(N-4), S2(N-3), S2(N-2), S2(N-1).

The final sequence S(n) is configured by using the above-mentioned sequences Sl(n) and S2(n). According to the sequence generation method of the present invention, individual elements of the final sequence S(n) can be represented by the following expression:

S(O)= Sl(O) +jS2(0)

S(I)= Sl(I) +jS2(l)

S(2)= Sl(2) +jS2(2) S(3)= Sl(3) +jS2(3)

S(N-4)= Sl(N-4) + jS2(N-4)

S(N-3)= Sl(N-3) + jS2(N-3)

S(N-2)= Sl(N-2) + jS2(N-2) S(N-I)= Sl(N-I) +jS2(N-l)

For the convenience of description and better understanding of the present invention, it is assumed that the sequence length N is 64, and each of Sl(n) and S2(n) is set to a 64-length Hadamard sequence. In order to scramble the final sequence, E(n) can be selectively used as described above. In case of using E(n), it is assumed that a single Golay sequence be used. An amount of information Sl(n) capable of being transmitted via each Hadamard sequence may be 64, and S2(n) may be 64.

A complex number-based sequence can also be used for a sequence generation method which is equal or similar to the above-mentioned sequence generation method. For example, if each sequence of Sl(n) and S2(n) is a complex- based sequence, a difference value between a real value of the first sequence Sl(n) and an imaginary value of the second sequence S2(n) may constitute a real value of the final sequence, and the sum of an imaginary value of the first sequence Sl(n) and the real value of the second sequence S2(n) may constitute an imaginary value of the final sequence. In other words, provided that Sl(n) is represented by Sl(n)=a(n)+jb(n), and S2(n) is represented by S2(n)=c(n)+jd(n), the final sequence can be represented by the following expression:

[Expression] S(n)=Sl(n)+jS2(n)-a(n)+jb(n)+j(c(n)+jd(n)-(a(n)-(n))+j(b(n)+c(n)) As described above, provided that the sequence is a binary sequence, the final sequence according to this embodiment may be represented as a sequence, a series of real value of which is composed of a first sequence, and a series of imaginary value of which is composed of a second sequence. In this way, provided that each of different sequences are composed of real and imaginary values, and a channel signal is transmitted using the above sequence, this channel signal may be transmitted in the same manner as in a Quadrature Phase Shift Keying (QPSK) scheme in which the transmitted channel signal is divided into an Inphase (I) component and a Quadrature (Q) component during the transmission time. In the case of using a coherent detection scheme which can recognize or estimate a channel value to detect a desired signal, a total amount of information capable of being transmitted may be denoted by 64 x 64 - 4096. In this case, an information index of the first sequence Sl(n) may be 0-63, an information index of the second sequence S2(n) may be 0~63, and consequently, a total information index capable of being possessed by the final sequence S(n) may be 0~4095.

If the non-coherent detection scheme is used because no channel value can be acquired, a maximum amount of information capable of being transmitted (i.e., the maximum number of combinations capable of being generated) may be ₆₄C₂ = 2016. In this case, ₆₄ C₂ indicates that only two combinations are selected from among 64 combinations and one of the two combinations is higher than the other one. That means selecting a combination in which the number of a second selection index is larger that that of a first selection index. The combination of (0, 1), (0, 2), (0, 3), (61, 62), (61, 63), (62, 63)) may exemplify such a combination. In this case, the number of necessary correlation calculations may be 64, which is relatively less than a total amount of transmittable information. In this case, an information index of the first sequence Sl(n) may be 0~63, an information index of the second sequence S2(n) may be 0-63, and consequently, a total information index capable of being possessed by the final sequence S(n) may be 0-2015. This transmission (Tx) signal can be represented by the following equation 5:

[Equation 5]

T(rt)=S(π)={ S_] (π)+jS₂(π)}E(n) In Equation 5, Sl(n) denotes a first sequence, S2(n) denotes a second sequence, S(n) denotes the final sequence acquired by the combination of the first sequence and the second sequence, and E(n) is an additionally-applied scramble sequence. In Equation 5, the transmission (Tx) signal is represented on a frequency domain. In the case of transmitting the signal of Equation 5, the signal received in a reception end is represented by the following equation 6: [Equation 6]

R(n)=T(n)H(n)+N(n)

In Equation 6, T(n) denotes a transmission (Tx) signal. For example, T(n) may be denoted by Equation 5. H(n) may indicate a channel value, and may be composed of a complex value. N(n) may be general noise of a channel, and may be an Additive White Gaussian Noise (AWGN).

For example, if the reception end receives the signal (e.g., the signal of Equation 6), it can detect the reception (Rx) signal using correlation calculation. The following equation 7 shows an exemplary correlation calculation method capable of being applied to the Rx signal: [Equation 7]

1-1

^C(^t) =£ n=0*(^»)(*(^«)) (*. (^»))

Equation 7 shows the correlation calculation of the reception (Rx) signal (e.g., R(n) shown in Equation 6). E(n) is a scramble sequence applied when a

S ^k (n) transmission end transmits a scramble-sequence resultant signal. ^base is an original sequence of the k-th index. In this case, C(k) is a correlation output (i.e., a correlation value) of a sequence corresponding to the k-th index of the corresponding sequence. Namely, C(k) has an inverse relationship with a cost function. In this embodiment, the calculation of Equation 7 with respect to a single k value is treated as one correlation calculation. In more detail, this embodiment can detect the Rx signal by performing the correlation calculations as many as the original sequences (i.e., the correlation calculations for the original sequence indexes), instead of performing correlation calculations as much as a total amount of information.

The final information can be detected by the soft-value combining method of two combinations. For example, using the cost function value C(3) with respect to index 3 of the sequence Sl and the cost function value C(5) with respect to index 5 of the sequence S2, the final cost function can be represented as following equation 8: [Equation 8]

|C(3)| ²+ |C(5)| ² In the case of transmitting the channel signal using the final sequence generated by the combination of at least two sequences, the transmission/reception operations will hereinafter be described in detail.

For the convenience of description and better understanding of the present invention, the combination capable of being generated by the non-coherent detection scheme (i.e., a total amount of information capable of being transmitted) may be represented by 64C2 = 2016. Also, the following description assumes that ₂₇C₂=351 among the total amount 2016 of available information are used. As described above, an exemplary index allocation method in case of transmitting information of 351 is shown in the following Table 1 : [Table 1]

A transmission end may select one of 351 data units, and transmit the selected one. Indexes 0-350 for the 351 data units can be represented by Table 1. In this case, provided that a combination is selected so that the index of S2(n) is higher than the other index of S 1 (n), it is sufficient for an information index of the index Sl(n) to be 0-25 among 0-62. In more detail, the transmission end selects only a combination in which the sequence index of S2(n) is higher than the other sequence index of Sl(n). So, if the final sequence is configured by combining the first sequence Sl(n) of the indexes 0-25 with the second sequence S2(n) of the indexes 1—26, total sequences (i.e., 351 sequences ) to be used can be generated.

In this case, operations at a reception end can be represented by Equation 7. In this case, the value of k has the range of 0-26, the reception (Rx) signal can be detected by a total of 27 correlation calculations. After calculating the cost function of the k value of 0-26, if the final cost function of the combination of Table 1 is calculated and compared, the final information can be detected. Also, as shown in Equation 8, the reception end may generate the above-mentioned final cost function value using the soft value combining method shown in Equation 8.

FIG. 3 is a conceptual diagram illustrating an example of a sequence combination method according to the present invention. In the case of using the above-mentioned two-layered sequence, in order to obviate a large number of requested calculations and transmit a large amount of information, a sequence combination method can be used. This sequence combination method combines at least two sequences, and transmits the combined result. In the case of mapping the combined result to a specific physical channel, the following two cases may be considered.

The first case is a localized structure. The second case is an interleaved structure. The localized structure is shown in FIG. 3(a), and is configured by interconnecting at least two sequences. In other words, individual sequences are successively mapped to a physical channel. The interleaved structure is shown in FIG. 3(b). In other words, at least two sequences are mixed with each other according to an interleaving method. In other words, elements of individual sequences are mapped to the physical channel according to the interleaving method.

FIG. 4 is a structural diagram illustrating the 10ms radio frame structure proposed by the 3GPP LTE according to the present invention. As described above, the highest priority matter for allowing a user equipment (UE) to communicate with a Node-B or base station is that the user equipment (UE) establishes synchronization with the Node-B over a synchronous (SCH) channel and then searches for a cell. This SCH channel may have a hierarchical structure, such that it may be classified into a primary-SCH (P-SCH) (40 and 42) channel and a secondary-SCH (S-SCH) channel (41 and 43).

Referring to FIG. 4, according to the 10ms radio frame structure proposed by the 3GPP LTE, each of the P-SCH and the S-SCH channel is transmitted two times within a single frame. If the sequence combination method of FIG. 3 is extended to add a single bit (1 bit) to be used as a frame boundary acting as a secondary synchronization code (SSC) of the 3GPP LTE, the method of FIG. 5 may be used.

FIG. 5 is a structural diagram illustrating an exemplary sequence combination method of the secondary synchronization code (SSC) of the 3GPP LTE according to the present invention.

FIG. 5 is an extended version of the sequence combination method of FIG. 3. FIG. 5(a) is an extended version of the localized structure of FIG. 3(a). FIG. 5(b) is an extended version of the interleaved structure of FIG. 3(b).

In other words, a frame boundary between two combinations shown in FIG. 5(a) can be discriminated by a secondary synchronization code (SSC). The sequence

Sl may be used as a first code, and the other sequence S2 may be used as a second code. The sequence Sl has a localized structure in which Si is leading Sj. The other sequence S2 has another localized structure in which Sj is leading Si.

In this way, as shown in FIG. 5(b), the sequence Sl may be used as a first code, and the other sequence S2 may be used as a second code. The sequence Sl has an interleaved structure in which Si is leading Sj. The other sequence S2 has another interleaved structure in which Sj is leading Si.

The final sequence mapped to the final channel is configured to have the above characteristic, and then the channel signal can be transmitted. Also, components are divided into several parts during the mapping time of the channel signal, such that the same or similar effects can be expected. A method for mapping at least one sequence to a channel and transmitting a sequence-based channel signal according to the present invention will hereinafter be described. FIG. 6 is a conceptual diagram illustrating a method for mapping the S-SCH signal using at least two sequences according to the present invention.

FIGS. 6(a)~6(b) show that two sequences, each of which has the length of N/2, are used to transmit a channel signal corresponding to a sequence having the length of N. In this case, two sequences are SSCl and SSC2, respectively. FIG. 6(a) shows a channel mapping method corresponding to a localized structure shown in FIG. 3(a) and/or FIG. 5(a). Referring to FIG. 6(a), SCCl having the length of N/2 is mapped to the channel according to a localized method, and SCC2 of the length of N/2 is mapped to the channel on a frequency axis according to a localized method. Specifically, it can be recognized that SSCl or SSC2 be mapped to only one component (e.g., an inphase (I) component) irrespective of a distinction between channel components. This mapping method is referred to as a conventional localized mapping scheme.

FIG. 6(b) shows a channel mapping method corresponding to an interleaved structure shown in FIG. 3(b) and/or FIG. 5(b). Referring to FIG. 6(b), SCCl having the length of N/2 is mapped to the channel according to an interleaved method, and SCC2 of the length of N/2 is mapped to the channel on a frequency axis according to an interleaved method. It can also be recognized that SSCl or SSC2 be mapped to only one component (e.g., an inphase (I) component) irrespective of a distinction between channel components. This mapping method is referred to as a conventional localized mapping scheme.

In the examples of FIGS. 6(a) and 6(b), it is obvious to those skilled in the art that the combination order of SSCl and SSC2 be changed to another order. Each of SSCl and SSC2 may use the final sequence capable of being generated according to one embodiment shown in FIG. 2. In other words, the final sequence generated by the combination of at least two sequences is used as the code set of SSCl equal to the localized structure of FIG. 6(a), or is used as the other code set of SSC2 equal to the interleaved structure of FIG. 6(b). The above-mentioned transmission scheme is unable to optimize the PAPR or CM value of the transmission end, such that it can perform the scrambling.

A Golay sequence modulated by Hadamard sequence has a low calculation number and an optimum PAPR among various sequences, and may have the structure of FIG. 1. In this case, the Golay sequence may be used as a scrambling sequence, and the Hadamard sequence may be used as an orthogonal sequence.

Although a sequence of an optimum PAPR is used, the structure of FIG. 2 is unable to optimize the PAPR. Specifically, if the OFDM system inserts the sequence in a frequency area, and a sequence-modulated Golay sequence is applied to the sequence combination method of FIG. 3, the present invention can transmit a sufficient amount of information using the combination of two Hadamard sequences, such that it is preferable that the number of Golay sequence categories be minimized if possible. In other words, it is preferable that the Golay sequence be used only to reduce the PAPR. Needless to say, another Golay sequence may also be used for information transmission. By the above-mentioned method, the number of correlation calculations of the reception end can be reduced, and at the same time a large amount of information can also be transmitted. For example, if N is 64, the mapping of FIG. 6 may be conducted by the combination of two sequences, each of which has the length of 32. Provided that the sequence is a Hadamard sequence, a total amount (32 x 32 = 1024) of information can be transmitted. Otherwise, in the case of selecting two information combinations, the total number of selecting the two information combinations without any overlap between them is denoted by ₃₂C₂ =240. In this case, it is sufficient that the number of calculations is considered to be correlation calculations denoted by 32+32=64.

FIG. 7 is a conceptual diagram illustrating a method for mapping the S-SCH signal using at least two SSC according to one embodiment of the present invention.

FIGS. 7(a)~7(b) show that two sequences, each of which has the length of N/2, are used to transmit a channel signal corresponding to a sequence having the length of N. In this case, two sequences are SSCl and SSC2, respectively.

FIG. 7(a) shows a channel mapping method corresponding to a localized structure shown in FIG. 3(a) and/or FIG. 5(a). Referring to FIG. 7(a), SCCl having the length of N/2 is mapped to the channel according to a localized method, and SCC2 of the length of N/2 is mapped to the channel on a frequency axis according to a localized method. Furthermore, referring to FIG. 7(a), SSCl having the length of N/2 is mapped to the channel according to the localized method, but SSCl is sequentially mapped to inphase (I) and quadrature (Q) components.

In other words, if Sl(O) of SSCl is mapped to the inphase (I) component and Sl(I) is mapped to the quadrature (Q) component, S 1(2) is mapped to the inphase (I) component. In this way, SSCl having the length of N/2 may be mapped to the channel according to the localized method. Similar to SSCl, SSC2 having the length of N/2 may be mapped to the channel according to the localized method, and may be sequentially mapped to the inphase (I) component and the quadrature (Q) component. FIG. 7(b) shows a channel mapping method corresponding to an interleaved structure shown in FIG. 3(b) and/or FIG. 5(b). Referring to FIG. 7(b), SCCl having the length of N/2 is mapped to the channel according to an interleaved method, and SCC2 of the length of N/2 is mapped to the channel on a frequency axis according to an interleaved method. Referring to FIG. 7(b), SSCl having the length of N/2 and SSC2 having the length of N/2 are mapped to the channel according to the interleaved method, but they are sequentially mapped to inphase (I) and quadrature (Q) components.

In other words, if Sl(O) of SSCl is mapped to the inphase (I) component and S2(0) of SSC2 is mapped to the quadrature (Q) component, and Sl(I) of SSCl is mapped to the inphase (I) component. S2(l) of SSC2 is mapped to the quadrature (Q) component. In this way, SSCl having the length of N/2 and SSC2 having the length of N/2 are mapped to the channel according to the interleaved method, such that it can be recognized that SSCl and SSC2 are sequentially mapped to inphase (I) and quadrature (Q) components. Each sequence of FIG. 7(a) or 7(b) is divided into inphase (I) and quadrature

(Q) components, the I and Q components are mapped to the channel. The operation, in which the same or different sequences are mapped to the I or Q components according to the interleaved method, may indicate that the other sequence mapped to the orthogonal sequence is mapped by the phase rotation of π/2 . The mapping method of FIG. 7(a) is a rotational localized mapping scheme, and the other mapping method of FIG. 7(b) is a rotational interleaved mapping scheme. In the examples of FIGS. 7(a) and 7(b), it is obvious to those skilled in the art that the combination order of SSCl and SSC2 may be changed to another order. Each of SSCl and SSC2 may use the final sequence capable of being generated according to one embodiment shown in FIG. 2. In other words, the final sequence generated by the combination of at least two sequences is used as the code set of SSCl equal to the localized structure of FIG. 7(a), or is used as the other code set of SSC2 equal to the interleaved structure of FIG. 7(b). FIG. 8 is a conceptual diagram illustrating a method for mapping the S-SCH signal using at least two sequences according to the present invention.

FIGS. 8(a)~8(b) show that two sequences, each of which has the length of N/2, are used to transmit a channel signal corresponding to a sequence having the length of N. In this case, two sequences are SSCl and SSC2, respectively. FIG. 8(a) shows a channel mapping method corresponding to a localized structure shown in FIG. 3(a) and/or FIG. 5(a). Referring to FIG. 8(a), SCCl having the length of N/2 is mapped to the channel according to a localized method, and SCC2 of the length of N/2 is mapped to the channel on a frequency axis according to a localized method. Furthermore, referring to FIG. 8(a), SSCl having the length of N/2 is mapped to the channel. Specifically, it can be recognized that SSCl is mapped to the inphase (I) component of the channel. In this way, SSCl having the length of N/2 may be mapped to the channel according to the localized method. Then, SSCl having the same length of N/2 may be mapped to the channel, but be mapped to the orthogonal component differently from SSCl. FIG. 8(b) shows a channel mapping method corresponding to an interleaved structure shown in FIG. 3(b) and/or FIG. 5(b). Referring to FIG. 8(b), SCCl having the length of N/2 is mapped to the channel according to an interleaved method, and SCC2 of the length of N/2 is mapped to the channel on a frequency axis according to an interleaved method. Referring to FIG. 8(b), SSCl having the length of N/2 and SSC2 having the length of N/2 are mapped to the channel according to the interleaved method. Sequences Sl(0)~Sl(m) of SSCl, and sequences S2(0)~S 1 (m)~S2(m) of SSC2 are mapped to the inphase (I) component. Sl(m+1)~S1(N-1) of SSCl, and S2(m+ I)-Sl (N- 1)~S2(N-1) of SSC2 are mapped to the quadrature (Q) component. In the examples of FIGS. 8(a) and 8(b), it is obvious to those skilled in the art that the combination order of SSCl and SSC2 may be changed to another order. Each of SSCl and SSC2 may use the final sequence capable of being generated according to one embodiment shown in FIG. 2. In other words, the final sequence generated by the combination of at least two sequences is used as the code set of SSCl equal to the localized structure of FIG. 8(a), or is used as the other code set of SSC2 equal to the interleaved structure of FIG. 8(b).

Each sequence of FIGS. 7(a)~7(b) or 8(a)~8(b) is divided into inphase (I) and quadrature (Q) components, the I and Q components are mapped to the channel. In this operation, the same or different sequences are mapped to the I and Q components according to the interleaved method, and the front part of the sequence and the rear part of the sequence are mapped to the orthogonal component. However, it should be noted that the above-mentioned mapping rule for dividing the sequence into the inphase (I) and quadrature (Q) components and mapping the divided result may be modified in various ways. In another embodiment of the present invention, at least two sequences may be used when the mapping method of FIGS. 7 and 8 is made available, but only one sequence may also be used. In other words, some components of a single sequence are mapped to inphase (I) components of the channel, such that they are transmitted as the I components. The remaining components are mapped to the quadrature (Q) components of the channel, such that they are transmitted as the Q components of the channel.

For example, if the embodiment of FIG. 7 is applied according to the single sequence S(n), S(O) is mapped to the I component of the channel, S(I) is mapped to the Q component of the channel, and S(2) is then mapped to the I component. In this way, each from S(O) to S(N-I) are mapped to the I and Q components according to the interleaved method. In other words, even index elements of the sequence S(n) are mapped to the I components, and odd index elements of the sequence S(n) are mapped to the Q components. Needless to say, the odd index elements of the sequence S(n) may also be mapped to the I elements, and the even index elements of the sequence

S(n) may also be mapped to the Q elements.

In the case of applying the embodiment of FIG. 8 using the single sequence

S(n), sequences from S(O) to S(N/2-l) are mapped to I components of the channel, and sequences from S(N/2) to S(N-I) are mapped to Q components of the channel. In this way, sequences from S(O) to S (N/2-1) are mapped to I components of the channel, and sequences from S(N/2) to S(N-I) are mapped to Q components of the channel.

Each element contained in the sequence according to the above-mentioned embodiments may have a real or imaginary value, or may also have a complex number as necessary. The above-mentioned channel mapping method has been disclosed on the basis of the synchronous channel of the 3GPP LTE, particularly, the S-SCH channel. As described above, it should be noted that the following embodiments of the present invention can also be equally applied to other sequence-based Tx channels, e.g., a random access channel (RACH), a DL/UL reference signal (RS), a DL/UL control channel, etc.

Generally, the above-mentioned channels can be provided other systems with to conduct the same functions, such that they can also be equally applied to other systems such as the IEEE 802.16e/m system. However, needless to say, the channel for providing other systems with the same function may also be referred to as other name different from that of the above-mentioned 3GPP LTE system. For example, according to the IEEE802.16 system, "SCH" may be called a "Preamble", "RACH" may be called a "Ranging", and "DL/UL reference signal" may be called a "DL/UL pilot". However, it is preferable that the above-mentioned channel mapping method be applied to other channels in consideration of characteristics of individual channels. For example, provided that a downlink reference signal (DL RS) is mapped at intervals of 6 sub-carriers, the channel mapping characteristics of the downlink reference signal (DL RS) are considered in the above-mentioned embodiments, and the resultant embodiments are mapped to the downlink reference signal (DL RS).

An example for applying the present invention to the DL/UL reference signal transmission will hereinafter be described in detail. If the transmission end transmits the reference signal by the present invention, the signal received in the reception end can be represented by the following equation 9: [Equation 9]

R(k)=C(k)H(k)+N(k)

In Equation 9, R(k) is a reception (Rx) signal, H(Jt) is a channel signal, N(k) is a noise signal (i.e., AWGN), and A; is a sequence index. In the case of using a Least Square (LS) method to perform channel estimation, the estimated channel can be represented by the following equation 10: [Equation 10]

^« , x ^R (^k )

^{1 }} C (Jt)

In this way, the estimated channel may be used to perform channel compensation when a signal modulated by the BPSK, QPSK, M-ary QAM is demodulated at other data parts. An exemplary signal demodulation method based on the channel estimation result of Equation 10 is represented by the following equation

11:

[Equation 11 ]

In Equation 11, ^ώfl^ Ms a Rx data signal, ⁵W is a Tx signal, #(*)

is a channel signal, ^da is a noise signal of Rx data, and ^H(k~) is an estimated channel signal. Generally, the reference signal is arranged in consideration of the coherent time/frequency, such that the channel of data can be compensated by an estimated channel, which is estimated from the reference signal.

Also, the example of applying the embodiment of the present invention to a UL preamble such as the RACH ranging will hereinafter be described. The RACH preamble according to this embodiment is transmitted from the user equipment (UE).

Generally, the RACH preamble may be used to perform UL synchronization, scheduling request such as bandwidth request, and timing/frequency maintenance, etc. The Node-

B or the base station detects the preamble transmitted via a RACH using the correlation calculation, such that it may perform scheduling request (e.g., bandwidth request or the time/frequency maintenance).

The above-mentioned RACH preamble may include the access opportunity information of the UE, and may be transmitted via the sequence. This opportunity information is related to the number of sequences capable of being used as a RACH preamble. The RACH preamble can be transmitted using the sequence generated by the above-mentioned embodiment, and the number of sequences can be increased, resulting in the increase in the number of UE opportunities.

If the sequence generated by the above-mentioned embodiment is applied to transmit the DL/UL ACK/NACK signals, the number of sequences may be used as ACK/NACK information.

If the sequences generated by this embodiment are applied to CQI transmission, the CQI value may be transmitted using the sequence. Namely, the sequences generated by this embodiment may be used as CQI information. If the sequences generated by this embodiment are applied to the control channel, control information may be configured by the above sequences as necessary.

If the sequences generated by the embodiment are applied to the general traffic channel, traffic channel data may be configured by the above sequences generated by this embodiment.

If each channel is multiplexed into at least two channels and then transmitted on the condition that the above sequences have been applied to transmit signals over the above synchronous channel, general traffic channels, or other various channels, the sequence generated by this embodiment may also be used to distinguish individual channels from each other. Also, if these sequences are CDM (Code Division Multiplexing) - processed between UEs, they may also be used to distinguish individual UEs from each other.

Besides the above-mentioned examples, if a general communication system uses such a sequence, the above-mentioned sequence generated by the aforementioned embodiment may also be widely used as necessary.

Next, preferred sequences capable of being applied to the above-mentioned embodiments will hereinafter be described. However, it should be noted that the following preferred sequences will be disclosed for only illustrative purposes, and will not be limited to only a specific sequence. Specifically, it is assumed that the following sequence be used as the above SSC.

The Hadamard orthogonal sequence from among various binary sequences is characterized in that it can greatly reduce the complexity encountered in the reception end by using FHT(Fast Hadamard Transform). However, if a scrambling is performed using the Hadamard sequence, there is needed a method for reducing the PAPR or CM because individual sequences of the Hadamard sequence may encounter a very high PAPR. In order to solve this problem, the Golay sequence may also be used as the scramble code. Specifically, if the Golay sequence modulated with the Hadamard sequence is applied to a total bandwidth using a single code, it can satisfy the proper PAPR within the range of 3dB without forming a pulse shape for Hadamard sequences.

For another example of the binary sequence, the m-sequence or the PN sequence may also be used. In this case, the ordering matrix or the re-ordering matrix is applied to the M-sequence, such that the FHT may be used to detect the M-sequence. As a result, the complexity encountered in the reception end can be reduced. The method for using the FHT to detect the M-sequence has been disclosed in <M. Cohn and A. Lempel, "on Fast M-sequence Transforms", IEEE Transactions on Information Theory, ppl35-137, January 1977>. Besides, it is obvious to those skilled in the art that other binary sequences (e.g., computer search sequences) may also be used.

FIG. 9 shows PDF graphs of PAPR and CM when the Golay sequence modulated with the 64-length Hadamard sequence is applied to a single code.

Referring to FIG. 9, the Golay sequence modulated with the Hadamard sequence can acquire a proper PAPR which cannot make the pulse shape of 3dB or less simultaneously while acquiring the CM of 2.9732dB or less. In other words, in the case of using the Golay sequence modulated with the Hadamard sequence as a SSC, the complexity of the transmission/reception end may be improved or the PAPR/CM may also be improved. Needless to say, the channel mapping method based on such a SSC can also be matched with the methods of FIGS. 6 to 8.

FIGS. 10~ 14 show the simulation resultant graphs of the embodiments shown in FIGS. 6~7 according to the present invention. The simulation results of the above-mentioned embodiments and their effects will hereinafter be described in detail.

The following table 2 shows the simulation parameters: [Table 2]

FIGS. 10~ 14 show the error detection rate graphs of the embodiments shown in FIGS. 6~7 illustrating the conventional localized mapping scheme, the conventional interleaved mapping scheme, the rotational localized mapping scheme, and the rotational interleaved mapping method.

Specifically, FIG. 10 shows the error detection rate graph of the above- mentioned four channel mapping structures under the condition that the residual frequency offset is O.Oppm. FIG. 11 shows the error detection rate graph of the above-mentioned four channel mapping structures under the condition that the residual frequency offset is 0.5ppm. FIG. 12 shows the error detection rate graph of the above-mentioned four channel mapping structures under the condition that the residual frequency offset is l.Oppm. FIG. 13 shows the error detection rate graph of the above-mentioned four channel mapping structures under the condition that the residual frequency offset is 1.5ppm. FIG. 14 shows the error detection rate graph of the above-mentioned four channel mapping structures of FIGS. 6 and 7 under the condition that the residual frequency offset is 2.0ppm.

Referring to the graphs of FIGS. 10 — 14, it can be recognized that the interleaved mapping scheme is superior to the localized mapping method in the aspect of a frequency diversity gain. If the residual frequency offset is relatively low, for example, if the residual frequency offset is lower than l.Oppm, the conventional mapping method may have the performance similar to that of the rotational mapping method. Otherwise, if the residual frequency offset is relatively high, for example, if the residual frequency offset is equal to or higher than 1.Oppm, the rotational mapping method may have the performance similar to that of the conventional mapping method. The higher the residual frequency offset, the higher the possibility of generating the worst case. Accordingly, the above-mentioned operations of the present invention may be considered to be effective operations.

The interference caused by the residual frequency offset from the neighboring sub-carrier can be removed by the above-mentioned rotational mapping method of FIG. 7 in which the SSC mapped to the neighboring sub-carrier is matched with different constellation domains, such that the above-mentioned advantageous effect can be acquired. According to the present invention, the above-mentioned SSC is mapped to different constellation domains (e.g., inphase or quadrature components orthogonal to each other) without increasing the complexity or the additional cost, such that the above-mentioned advantageous effect can be acquired.

FIGS. 15- 18 show PDF graphs of PAPR and CM acquired when the Golay sequence modulated with the Hadamard sequence is used as the SSC according to a conventional interleaved mapping scheme, a localized mapping scheme, a rotational interleaved mapping scheme, and a rotational localized mapping scheme.

If the above-mentioned four mapping methods of FIGS. 15- 18 are used, it can be recognized that the four mapping methods have the almost same PAPR and CM values. In other words, in the case of using the localized mapping method and the interleaved mapping method, the above four mapping methods have the almost same PAPR and CM characteristic values. Also, in the case of using the conventional mapping method and the rotational mapping method, they have the almost same PAPR and CM characteristic values. Therefore, although the above-mentioned four mapping methods are applied when the Golay sequence modulated with the Hadamard sequence is used as the SSC, it may be considered that the above four mapping methods may have the same PAPR and CM characteristic values.

According to another embodiment of the present invention, the present invention may differently determine whether each cell includes the real and imaginary value, and may generate a corresponding sequence according to the determined result. For example, a specific cell loads a sequence on only a real part (i.e., a real value), and transmits the real part, and the other cell loads a sequence on only an imaginary part (i.e., an imaginary value), and transmits the imaginary part. Otherwise, a mapping rule of the I and Q components is differently applied to each cell, such that the channel signal is then transmitted according to the resultant mapping rule. For example, in a specific cell, a sequence is mapped to only the I component of the channel, and the mapping result is transmitted. In the other cell, a sequence is mapped to only the Q component of the channel, and the mapping result is transmitted. In this way, the sequence generation method or the channel mapping method is differently applied to individual cells, such that the inter-cell interference amount may be reduced or the diversity effect can be acquired from the constellation mapping process.

According to the above embodiment in which the sequence composed of the real and imaginary values is used or according to the other embodiment in which the sequence is divided into I and Q components while it is mapped to the channel, if a general sequence combination method is compared with the localized structure case or the interleaved structure case in the aspect of the number of calculations, the above sequence combination method has the same number of calculation as that of either the localized structure case or the interleaved structure case. However, it can be readily noted that the above-mentioned sequence combination method can transmit much more information than those of the localized structure case or the interleaved structure case.

Also, the present invention can use all the sub-carriers, such that it is superior to the localized structure case or the interleaved structure case in the aspect of the resource use. In addition, the present invention has improved interference averages, improved frequency diversities, and a long sequence, such that it has performances superior to those of the localized structure case or the interleaved structure case.

Furthermore, if the Golay-sequence-based scrambling is performed on all parts of the sequence composed of the real and imaginary parts created by the above- mentioned embodiments, the PAPR can be more optimized. According to the above-mentioned embodiments, the present invention can basically acquire the sufficient interference averages, the frequency diversity (OFDM case), and the spreading gain effect.

Although the above-mentioned embodiments have disclosed the frequency hopping scheme available for uplink data packet transmission, it should be noted that the present invention can also be applied to downlink data packet transmission.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

That is, the present patent is not limited to the embodiments described herein and should be interpreted to have the widest range according to the principles and features disclosed herein.

[Industrial Applicability]

As apparent from the above description, the present invention transmits a channel signal using at least one sequence. In this case, this channel signal is divided into at least two component signals capable of being discriminated by a reception end, such that the reception end can more easily detect the channel signal. There is no need for the system of the present invention to be limited to the OFDM system, the OFDMA system, the 3GPP LTE system, the IEEE 802-based system (e.g., the multi-carrier system such as the IEEE 802.16e or IEEE 802.16m system), and the above system of the present invention can also be applied to base stations, switching centers, and mobile stations of various wireless communication systems compatible with the 3GPP LTE, IEEE 802.16e, and IEEE 802.16m systems.

Claims

[CLAIMS]

[Claim 1 ] A method for transmitting a sequence-based signal in a communication system comprising: selecting at least one sequence; and mapping the selected at least one sequence to at least one of an inphase (I) component and a quadrature (Q) component to transmit a signal.

[Claim 2] The method according to claim 1, wherein some elements of each of the at least one sequence are mapped to the inphase (I) component, and remaining elements of each of the at least one sequence are mapped to the quadrature (Q) component.

[Claim 3) The method according to claim 1, wherein some elements of the at least one sequence are mapped to the inphase (I) component, and other elements of the at least one sequence are mapped to the quadrature (Q) component.

[Claim 4] The method according to claim 1, wherein at least one of the selected sequences is configured by a sum of a first sequence and a second sequence multiplied by an imaginary unit (j), in which a square of the imaginary unit (j) is '-1'.

[Claim 5] The method according to claim 4, wherein at least one of the selected sequences is configured such that a third sequence is multiplied by the first sequence and a fourth sequence is multiplied by the second sequence.

[Claim 6] The method according to claim 4, wherein the first sequence and the second sequence are either homogeneous sequences or heterogeneous sequences.

[Claim 7] The method according to any one of claims 1 to 3, wherein the at least one of the selected sequences are mapped according to a sequence combination scheme when the at least one of the selected sequences are mapped to a channel.

[Claim 8] The method according to claim 7, wherein the sequence combination scheme is a scheme by which each of one sequence and another sequence among the selected at least one sequence is mapped on the channel along with a sub-carrier axis in a localized structure.

[Claim 9] The method according to claim 7, wherein the sequence combination scheme is a scheme by which each of one sequence and another sequence among the selected at least one sequence is mapped on the channel along with a sub-carrier axis in a interleaved structure.

[Claim 10] A sequence generation method comprising: selecting a first sequence and a second sequence; and generating a sequence by adding the first sequence and the second sequence multiplied by an imaginary unit 'j', wherein a value of a square of the imaginary unit 'j' is '-1'.

[Claim 11 ] The sequence generation method according to claim 10, wherein: the sequence is configured such that a third sequence is multiplied by the first sequence and a fourth sequence is multiplied by the second sequence, or such that the third sequence is multiplied by the sum of the first and second sequences.

[Claim 12] The sequence generation method according to claim 10 or 11, wherein at least one of the first sequence, the second sequence, and the third sequence is a complex signal including at least one of a real part and an imaginary part.

[Claim 13] The sequence generation method according to claim 12, wherein at least one of the first sequence, the second sequence, and the third sequence is either one of a scramble sequence and a quadrature sequence.

[Claim 14] The sequence generation method according to claim 10, wherein the first sequence and the second sequence are either homogeneous sequences or heterogeneous sequences.

[Claim 15] A method for transmitting a sequence-based channel signal in a mobile communication system comprising: selecting a sequence; and transmitting a signal through both an inphase (I) channel and a quadrature (Q) channel of the channel using the selected sequence.

[Claim 16] The method according to claim 15, wherein the sequence uses at least two different sequences, and real and imaginary parts of the sequence are composed of different sequences.

[Claim 17] A method for transmitting a signal in a communication system including a plurality of cells, comprising: using at least one of sequence generation schemes and at least one of sequence-based channel signal transmission schemes, wherein the sequence generation schemes are different in each cell, and, the sequence-based channel signal transmission schemes are different in each cell wherein the sequence generation scheme generates a sequence by configuring at least two sequences with real part and imaginary part, and the sequence-based channel signal transmission scheme divides at least one sequence into an inphase part and a quadrature part, each of which mapped onto an inphase component and a quadrature component of a channel respectively to be transmitted.

[Claim 18] The signal transmission method according to claim 17, wherein individual element of the sequence is a complex signal including at least one of a real part and an imaginary part.

[Claim 19] A method for transmitting a sequence-based signal comprising: selecting a sequence, which is configured by a sum of a first sequence and a second sequence multiplied by an imaginary unit 'j'; and transmitting a signal using the selected sequence.

[Claim 20] The method according to claim 19, wherein the signal includes at least one of a synchronous channel (SCH), a random access channel (RACH), a control channel (CCH), and a reference signal (RS).