RU2434346C2 - Method of setting cyclic shift considering frequency offset - Google Patents

Abstract

FIELD: information technology.

SUBSTANCE: first variable (d_u) of cyclic shift corresponding to Doppler shift of one subcarrier spacing is obtained by using a root index (u) of the given sequence; secondary variables are obtained using the first variable (d_u), where the secondary variables comprise a number of groups (G) formed by grouping said sequence, a length of the each group (S) and the number of applicable cyclic shifts (P) per group; and the cyclic shift to be applied to said sequence according to the secondary variables is established.

EFFECT: high carrying capacity.

24 cl, 24 dwg

Description

FIELD OF THE INVENTION

The present invention relates to a sequence of a wireless communication system and, in particular, to a method for setting a cyclic shift taking into account the characteristics of a CAZAC sequence to solve a frequency shift problem.

State of the art

The constant amplitude and zero autocorrelation sequence (CAZAC sequence) is one of the various sequences that have been intensively discussed in the context of the 3GPP LTE technology (hereinafter, 3GPP LTE).

Channels typically retrieve many different identifiers (IDs) or information using a CAZAC sequence, for example, synchronization channels (e.g., primary SCH, secondary SCH, and BCH (broadcast channel)) for downlink synchronization, other synchronization channels (e.g., RACH ( random access channel)) for uplink synchronization and pilot channels (e.g., data pilot and channel quality pilot). In addition, the aforementioned CAZAC sequence was used to perform scrambling.

Two types of methods were applied to the CAZAC sequence, namely, the first method for changing the root index to another root index and applying the changed root index and the second method for performing a cyclic shift (CS) for a single root sequence and applying the CS result.

If the current root index is changed to a new root index, a weak cross-correlation occurs between the current root index and the new root index, but there are no restrictions on the development of the use of sequences.

In the case of a cyclic shift, the cross-correlation between the current root index and the new root index is zero, and therefore two root indices are used when each of the root indices needs a high suppression coefficient. In particular, when time-frequency resources are shared in one cell and data / control signals are transmitted, the two root indexes mentioned above are adapted to distinguish between different signals or UE devices.

A typical example of CAZAC sequences is the Zadov-Chu sequence (ZC sequence), and the Zadov-Chu sequence can be described by the following equation 1:

[Equation 1]

для нечетных Nzc,

for odd Nzc,

для четных Nzc,

for even Nzc,

where “n” indicates the index of the sample, “Nzc” indicates the length of the ZC sequence, and “u” indicates the root index of the ZC sequence.

However, if a shift in the frequency domain occurs in the same manner as in the case where the CAZAC sequence is transmitted using the OFDM (orthogonal frequency division multiplexing) scheme, then an excessive degradation in the functional characteristic or frequency of the false alarm signal or throughput is possible.

In particular, if a cyclic shift (CS) is applied to the CAZAC sequence, then the frequency or time shift occurs excessively, so it is difficult to distinguish between the sequences.

SUMMARY OF THE INVENTION

Technical challenge

Accordingly, the present invention relates to such a method of setting a cyclic shift (CS) taking into account the frequency shift, which essentially eliminates one or more problems, due to the limitations and disadvantages of related technical devices.

It is an object of the present invention to provide a method for setting a cyclic shift (CS) to counteract a frequency shift, so that said method can easily prevent a sequence degradation (e.g., a CAZAC sequence) under conditions where a frequency shift occurs.

Additional advantages, objects, and features of the invention are set forth in part in the following description and in part will become apparent to those of ordinary skill in the art after studying the following material, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and carried out using the structure, partially shown in the above description and the claims of the present invention, as well as in the accompanying drawings.

Technical solution

To accomplish the aforementioned tasks and obtain other advantages and, in accordance with the purpose of the invention, as shown and widely explained in this application, a method for performing a cyclic shift setting is provided, which should be applied to this sequence to counteract the influence of a Doppler frequency higher than a predetermined value. In accordance with this method, the following steps are performed: receive the first variable (d _u ) of the cyclic shift corresponding to the Doppler shift of the spacing of one subcarrier using the root index (u) of this sequence; secondary variables are obtained containing the number of groups (G) contained in a given sequence, the length of each group (S) and the number of cyclic shifts per group (P) using the first variable (d _u ); and establish a cyclic shift, which should be applied to this sequence, in accordance with the secondary variables.

In a preferred embodiment, the secondary variables additionally contain a number of additional cyclic shifts that are applicable to this sequence, not based on group (R).

In a preferred embodiment, the sequence is a Zadoff-Chu sequence (ZC sequence), and the first variable is obtained according to the equation

where “u” means the root index of the ZC sequence, and “N _ZC ” corresponds to the length of the ZC sequence.

And, in this case, the secondary variables are obtained differently, depending on the range of the first variable (d _u ), and the range of the first variable is divided using a criterion corresponding to 1/3 of the length of the given sequence (Nzc / 3).

And, if the range of the first variable (d _u ) is Ncs≤d _u <(Nzc / 3), then the secondary variables can be obtained according to the equations

where “N _CS ” is a predetermined cyclic shift parameter, “P” corresponds to the number of cyclic shifts per group, “S” corresponds to the length of each group, “G” corresponds to the number of groups, and “R” corresponds to the number of additional cyclic shifts.

On the other hand, if the range of the first variable (d _u ) is (Nzc / 3) ≤d _u ≤ (Nzc-Ncs) / 2, then the secondary variables can be obtained according to the equations

where “N _CS ” is a predetermined cyclic shift parameter, “P” corresponds to the number of cyclic shifts per group, “S” corresponds to the length of each group, “G” corresponds to the number of groups, and “R” corresponds to the number of additional cyclic shifts.

And, in a preferred embodiment, said cyclic shift setting ( C _ν ) is performed in accordance with an equation of the form

C _ν = S · [ ν / P ] + ( ν mod P ) · N _CS , ν = 0,1, ..., ( P · G + R-1).

And this sequence can serve to generate a random access preamble.

In accordance with another aspect of the present invention, there is provided a method for adjusting a cyclic shift to be applied to a given sequence, the method comprising the steps of: determining whether to establish a cyclic shift in accordance with limited sets limited due to Doppler shift; and set the cyclic shift that should be applied to this sequence, taking into account the cyclic shift corresponding to the Doppler shift of the separation of one subcarrier, if it is determined that the cyclic shift should be set in accordance with limited sets.

In a preferred embodiment, when it is determined that the cyclic shift should be set in accordance with the limited sets, said cyclic shift setting to be applied to the sequence comprises the following steps: a first variable (d _u ) is obtained indicating the cyclic shift corresponding to the Doppler spacing shift one subcarrier using the root index (u) of a given sequence; secondary variables are obtained containing the number of groups (G) contained in a given sequence, the length of each group (S), the number of cyclic shifts per group (P) using the first variable (d _u ), and the number of additional cyclic shifts that apply to this sequence, not based on group (R); and establish a cyclic shift, which should be applied to this sequence, in accordance with the secondary variables.

In a preferred embodiment, the sequence is a Zadoff-Chu sequence (ZC sequence), and the first variable is obtained according to the equation

,

,

where “u” means the root index of the ZC sequence, and “N _ZC ” corresponds to the length of the ZC sequence.

And the secondary variables can be obtained differently, depending on the range of the first variable (d _u ), and the range of the first variable is divided using the criterion corresponding to 1/3 of the length of this sequence (Nzc / 3).

In this case, if the range of the first variable (d _u ) is Ncs≤d _u <(Nzc / 3), then the secondary variables are obtained according to the equations

where “N _CS ” is a predetermined cyclic shift parameter, “P” corresponds to the number of cyclic shifts per group, “S” corresponds to the length of each group, “G” corresponds to the number of groups, and “R” corresponds to the number of additional cyclic shifts.

On the other hand, if the range of the first variable (d _u ) is (Nzc / 3) ≤d _u ≤ (Nzc-Ncs) / 2, then the secondary variables can be obtained according to the equations

where “N _CS ” is a predetermined cyclic shift parameter, “P” corresponds to the number of cyclic shifts per group, “S” corresponds to the length of each group, “G” corresponds to the number of groups, and “R” corresponds to the number of additional cyclic shifts.

And, in a preferred embodiment, the cyclic shift ( C _ν ) is performed according to the following equation,

And this sequence can serve to generate a random access preamble.

In accordance with another aspect of the present invention, there is provided a method for adjusting a cyclic shift to be applied to a given sequence, the method comprising the following steps: (a) obtaining the variable d _u from the equation

,

,

where "u" means the root index of a given sequence, and "N _ZC " corresponds to the length of this sequence; (b) get the variables G, S, P and R from the equations

when the range of the first variable (d _u ) is Ncs≤d _u <(Nzc / 3), and the variables G, S, P and R are obtained from the equations

when the range of the first variable (d _u ) is (Nzc / 3) ≤d _u ≤ (Nzc-Ncs) / 2,

where “N _CS ” is a predetermined cyclic shift parameter; (c) establish a cyclic shift ( C _ν ) according to the equation

in which the restricted sets are sets of cyclic shifts limited due to Doppler shift, and the unlimited sets are sets of cyclic shifts not limited due to Doppler shift.

In accordance with another aspect of the present invention, there is provided a method for transmitting a random access preamble using a cyclic shift, the method comprising the steps of: obtaining a root index (u) of a random access preamble sequence from system information; establish a cyclic shift, which should be applied to this sequence, and with the above installation, when it is determined that the cyclic shift should be set in accordance with limited sets limited due to Doppler shift, the cyclic shift that should be applied to this sequence is set taking into account the cyclic shift corresponding to the Doppler shift of the spacing of one subcarrier; generate a sequence in accordance with the root index (u), with the established cyclic shift; and transmitting the cyclic-shifted sequence as a random access preamble.

In a preferred embodiment, when it is determined that the cyclic shift should be set in accordance with the limited sets, said setting of the cyclic shift to be applied to the sequence comprises the following steps: a first variable (d _u ) indicating the cyclic shift corresponding to the Doppler separation shift is obtained one subcarrier using the root index (u) of a given sequence; secondary variables are obtained containing the number of groups (G) contained in a given sequence, the length of each group (S), the number of cyclic shifts per group (P) using the first variable (d _u ), and the number of additional cyclic shifts that apply to a given sequence, not based on a group (R); and establish a cyclic shift, which should be applied to the sequence, in accordance with the secondary variables.

In a preferred embodiment, in which the sequence is a Zadoff-Chu sequence (ZC sequence), and the first variable is obtained according to the equation

where “u” means the root index of the ZC sequence, and “N _ZC ” corresponds to the length of the ZC sequence.

In a preferred embodiment, the secondary variables are obtained differently, depending on the range of the first variable (d _u ), and the range of the first variable is partitioned using a criterion corresponding to 1/3 of the length of the sequence (Nzc / 3).

In particular, if the range of the first variable (d _u ) is Ncs≤d _u <(Nzc / 3), then the secondary variables can be obtained according to the equations

where “N _CS ” is a predetermined cyclic shift parameter, “P” corresponds to the number of cyclic shifts per group, “S” corresponds to the length of each group, “G” corresponds to the number of groups, and “R” corresponds to the number of additional cyclic shifts.

On the other hand, if the range of the first variable (d _u ) is (Nzc / 3) ≤d _u ≤ (Nzc-Ncs) / 2, then the secondary variables can be obtained according to the equations

where “N _CS ” is a predetermined cyclic shift parameter, “P” corresponds to the number of cyclic shifts per group, “S” corresponds to the length of each group, “G” corresponds to the number of groups, and “R” corresponds to the number of additional cyclic shifts.

And, in a preferred embodiment, the cyclic shift ( C _ν ) is performed according to the following equation

It should be understood that both the foregoing general description and the following detailed description serve as an example and explanation and are intended to provide further explanation of the claimed invention.

Technical result

The present invention makes it easy to set the cyclic shift interval (CS) in a particular place, without overlapping, taking into account the channel response of the received (Rx) sequence and the false position of this received (Rx) sequence, although the received (Rx) signal is shifted by the amount of frequency shift categories of the area generating the sequence, so that the number of detection errors and the frequency of false alarms can be significantly reduced.

And, if a cell with a frequency shift exceeding a predetermined level is assigned a cyclic shift sequence (CS), then the present invention minimizes the effect of the frequency shift on a cell with significant subscriber mobility.

Description of drawings

The accompanying drawings, which are included to provide a deeper understanding of the invention, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

In the drawings:

FIG. 1 is a conceptual diagram depicting the effect of a frequency shift caused by pulse generation in the frequency domain when a sequence is mapped to a subcarrier, in accordance with the present invention;

FIG. 2 is a conceptual diagram depicting different frequency shift situations existing in a plurality of cells in accordance with the present invention;

FIG. 3 is a conceptual diagram representing a method for assigning a sequence when the sequence is a CAZAC sequence in accordance with the present invention;

FIG. 4 is a conceptual diagram depicting spurious components that occur in a channel response in a frequency domain of a received sequence due to a frequency shift, in accordance with the present invention;

FIG. 5 is a conceptual diagram showing a method of installing a new cyclic shift (CS) application unit by introducing an additional spare field into the old CS application unit, in accordance with the present invention;

FIG. 6 and 7 are conceptual diagrams depicting examples of the application of the additional spare field shown in FIG. 5, under conditions where the sequence index is of little importance, in accordance with the present invention;

FIG. 8 and 9 is a conceptual diagram illustrating exemplary additional spare fields shown in FIG. 5, under conditions where the sequence index is of great importance, in accordance with the present invention;

FIG. 10 is an example of a single group consisting of P sets of cyclic shifts in accordance with the present invention;

FIG. 11 is a conceptual diagram representing a method of setting a cyclic shift application group and a cyclic shift application interval for each group in accordance with the present invention;

FIG. 12 shows the positions where the pulses occur due to mutual interference when the CAZAC index is contained in the interval N / 3 - N / 2 in accordance with the present invention;

FIG. 13 is a flowchart depicting obtaining a limited set of cyclic shifts in accordance with one embodiment of the present invention;

FIG. 14 is a conceptual diagram showing a method of setting a cyclic shift variable (d _u ) corresponding to a Doppler shift associated with a subcarrier spacing 1 when a limited set of cyclic shifts is set up in accordance with the present invention;

FIG. 15 is a conceptual diagram representing a special case in which a variable (d _u ) is smaller than a main block N _CS to which a cyclic shift (CS) is applied, in accordance with the present invention;

FIG. 16 is a conceptual diagram representing a method of computing a variable establishing a cyclic shift in the range of N _CS ≤ d _u <(N _ZC / 3), in accordance with the present invention;

FIG. 17 is a conceptual diagram representing a method of computing a variable establishing a cyclic shift in the interval (N _ZC / 3) ≤ d _u <(N _ZC -N _CS ) / 2, in accordance with the present invention;

FIG. 18 and 19 are conceptual diagrams representing a method of reducing the number of ZCZ preamble sequences due to a false response when Nzc = 839, Ncs = 100, and d _u = 155, in accordance with the present invention;

FIG. 20 is a conceptual diagram showing an increase coefficient of an available limited cyclic shift after the restriction of the initial position of the cyclic shift is removed in the case of Nzc = 839, in accordance with the present invention;

FIG. 21 is a conceptual diagram depicting an exemplary cyclic shift in the case where Nzc = 839, Ncs = 40, and d _u = 150, in accordance with one embodiment of the present invention;

FIG. 22 is a conceptual diagram depicting an exemplary cyclic shift in the case where Nzc = 839, Ncs = 40, and d _u = 399, in accordance with one embodiment of the present invention;

FIG. 23 is a conceptual diagram depicting an exemplary cyclic shift in the case where Nzc = 839, Ncs = 40, and d _u = 150, in accordance with another embodiment of the present invention; and

FIG. 24 is a conceptual diagram depicting an exemplary cyclic shift in the case where Nzc = 839, Ncs = 40, and d _u = 399, in accordance with another embodiment of the present invention.

An embodiment of the invention

Below are detailed references to preferred embodiments of the present invention, examples of which are shown in the accompanying drawings. Hereinafter, wherever possible, the same reference numerals throughout the drawings are used to refer to the same or like parts.

Before describing the present invention, it should be understood that most of the terms described in the present invention correspond to general terms commonly known in the art, but some of the terms are selected by the author of this application as necessary and are further explained in the following description of the present invention. Therefore, it is advisable that the terms introduced by the author of this application be understood on the basis of their semantic meaning in the present invention.

For convenience of description and ease of understanding of the present invention, the general structures and devices commonly known in the art are not mentioned below or are denoted by flow charts or flowcharts. Whenever possible, the same numeric positions are used throughout the drawings to refer to the same or like parts.

The present invention provides a cyclic shift (CS) setting method for counteracting a frequency shift, such that the method can easily prevent degradation of a sequence (e.g., CAZAC sequence). To this end, the present invention provides a method for applying a cyclic shift to a CAZAC sequence and the influence of the frequency shift of the CAZAC sequence.

A cyclic shift can be applied to a CAZAC sequence in accordance with two schemes, namely, the first scheme for performing a cyclic shift on a sequence and a method for multiplying the exponential function of other sections by a sequence in the time or frequency domain and performing a cyclic shift on the result of multiplication.

The cyclic shift “d” is applied to the “k” index in frequency in the frequency domain. If the sequence index is M and the sequence of length N is represented as c (k; d, M, N), then the method of performing a cyclic shift on the sequence can be represented by the following equation 2:

[Equation 2]

Where “d” means the magnitude of the cyclic shift, and “mod” means the modular operator.

The method of applying the cyclic shift by multiplying the exponential function by a sequence can be expressed by the following equation 3:

[Equation 3]

In the meantime, although each of the above equations 2 and 3 shows an exemplary cyclic shift applied in the frequency domain, the cyclic shift can be applied to a sequence in the time domain with the sample index “n” in the time domain. In this case, an example of applying a cyclic shift can be represented by the following equation 4:

[Equation 4]

,

,

where “C _ν ” means the degree of cyclic shift, “n” means the index of the sample, “N _ZC ” means the length of the ZC sequence, and “u” means the root index of the ZC sequence.

CAZAC sequences can be distinguished from one another provided that different root indices are used, but it should be noted that CAZAC sequences differ in cross-correlation.

However, in the case of at least two CAZAC sequences associated with a cyclic shift, the cross-correlation value between the CAZAC sequences is zero, since the aforementioned CAZAC sequences are used when a high rejection ratio for two CAZAC sequences is required.

In particular, cyclic shift CAZAC sequences share time-frequency resources within a single cell, so that they can be used to distinguish between different signals / UEs during data / control signals.

However, if the frequency shift in the frequency domain occurs in the same manner as in the case in which the CAZAC sequence is transmitted using the OFDM scheme, then, within the framework of the present invention, one may encounter excessive deterioration in the functional characteristic and frequency of the false alarm signal.

The following description provides an example in which a sequence is transmitted in the frequency domain, and another example in which a sequence is transmitted using an OFDM scheme.

In FIG. 1 is a conceptual diagram depicting the effect of a frequency shift caused by pulse generation in the frequency domain when a sequence is mapped to a subcarrier, in accordance with the present invention.

As shown in FIG. 1, each of the sequence samples is mapped to a subcarrier. If the receiving station samples the signal due to a frequency shift, as indicated by the “interference” location, then the signals of adjacent subcarriers are mixed within a single reference. In other words, if the pulse shaping function has the form p (x), then the response of an arbitrary subcarrier can be represented by the following equation 5:

[Equation 5]

where “r (k, f _off )” means a particular response characteristic in receive mode (Rx) at the location of the kth subcarrier if the frequency shift is f _off , “c (n)” means a CAZAC sequence mapped to a subcarrier by user equipment ( UE), “p (f)” means the pulse shaping function in the frequency domain, and ω ₀ characterizes the subcarrier spacing.

In the case f _off = 0, the above equation 5 gives only the value c (k). Otherwise, in the case of f _off ≠ 0, the signal of the adjacent subcarrier may arrive at the receiving station so that the functional characteristics of the receiving station deteriorate. Due to the deterioration of the functional characteristics caused by the frequency shift, the probability of encountering a detection error at the receiving station increases, and the frequency of false alarms and / or skipping detection can inevitably increase at the receiving station.

In particular, if a cyclic shift is applied in the time domain and the CAZAC sequence is transmitted in the frequency domain, it is not possible to distinguish between the different sequences. And the above problem may occur in a situation even when the CAZAC sequence is transmitted in the time domain as a time shift.

In other words, if a frequency or time shift occurs, the methods of applying the cyclic shift must inevitably undergo a deterioration in functional characteristics. In addition, the effect of the frequency shift is equally applicable to a particular case in which a cyclic shift is applied in the time domain, as expressed by equation 4.

Therefore, there is an urgent need to develop a new technology to prevent the degradation of the functional characteristics of the sequence (i.e., the CAZAC sequence) under conditions when a frequency shift occurs.

In particular, when applying a cyclic shift to a CAZAC sequence, an excessive frequency or time shift occurs, so that, within the framework of the present invention, it is difficult to distinguish between sequences when the frequency or time shift occupies at least half the spacing of one subcarrier.

However, the magnitude of the frequency shift and the magnitude of the Doppler shift may be different in individual cells of a cellular mobile communication system.

Therefore, in accordance with one embodiment, the present invention provides various methods for setting a cyclic shift (CS) according to the frequency shifts of individual cells, and the following is a detailed description of said methods.

In FIG. 2 is a conceptual diagram depicting various frequency shift situations existing in a plurality of cells in accordance with the present invention.

As shown in FIG. 2, the present invention makes it possible to determine that a particular cell containing many UE devices with high mobility in a cellular mobile communication system containing many cells has a large frequency shift. A UE within a cell covering residential areas is very likely to be a low speed UE, so the frequency shift within the cell may be small.

In FIG. 2 shows in more detail cells A and B adjacent to the high-speed railway and cell C remote from the high-speed railway.

In the case of cells A and B adjacent to the high-speed railway, it is very likely that there are many high-speed UE devices in the corresponding cell, so the present invention offers the advantage that a sequence that is very resistant to frequency shift can be assigned.

For example, in the case of cell C near a residential area remote from the high-speed railway, the likelihood of a high-speed device UE staying in the corresponding cell is relatively low, which eliminates the need to assign only a sequence that is very resistant to frequency shift.

In the case of an available sequence (for example, a CAZAC sequence), the first sequences caused by the root indices of the individual sequences and the second sequences caused by the cyclic shift applied to the first sequences may have different frequency shift characteristics.

Therefore, the present invention establishes a limited case and an unlimited case and provides methods for setting a cyclic shift for individual cases.

The limited case means that the influence of the Doppler shift is higher than the predetermined threshold value, so that setting an interval for applying the cyclic shift (CS) causes an unexpected limitation.

An unlimited case means that the influence of the Doppler shift is equal to or less than a predetermined threshold value, so there is no restriction when setting the CS application interval.

The following is a detailed description of the cyclic shift setting method.

In FIG. 3 is a conceptual diagram depicting a sequence assignment method when the sequence is a CAZAC sequence in accordance with the present invention.

A CAZAC sequence can contain the root sequence of each root CAZAC sequence and a sequence with a zero correlation zone (ZCZ sequence), to which different cyclic shifts are applied (also called circular shifts).

In addition, in FIG. Figure 3 shows the root sequence for each root index in the Nt root indexes and a set of ZCZ sequences in which L cyclic shifts are applied to each root sequence.

In this case, the ZCZ indicates the cyclic shift application interval to which the cyclic shift (CS) is applied so that the Node B can distinguish the RACH signals.

Meanwhile, if the CAZAC sequence is used when a frequency shift occurs, then within the scope of the present invention, it is possible to distinguish between the ZCZ sequence during the frequency shift. Therefore, the present invention makes it possible to determine that the ZCZ sequence is not used in a predetermined cell with a frequency offset exceeding a predetermined level.

At the same time, the choice of the threshold value used to decide on the magnitude of the frequency shift of each cell can be made correctly depending on the number of available sequences of the corresponding system and the magnitude of the frequency shift of each cell.

If it is determined that there is a frequency shift in the cell that exceeds a predetermined level, then the probability of the high-speed UE being in the cell is very high, as shown for cell A or B.

However, if it is determined that the ZCZ sequence is not used in a cell with a frequency offset exceeding a predetermined level, then only Nt indices based on CAZAC indices are possible, so that the number of available sequences becomes smaller.

If the sequence reuse factor becomes smaller, the sequences should be assigned in accordance with cell planning. However, this assignment based on cell scheduling may unexpectedly increase the complexity of the process of assigning sequences to individual cells, so another solution may be needed additionally when the number of available sequences is a problem.

In addition, if only Nt sequences are used and the ZCZ sequence is not used, the problem of estimating two-way delay or one-way delay may occur, while the sequence detection characteristic is improved. That is, a problem may arise in recognizing the position of a correlation peak changing due to a two-way delay or one-way delay, and the position of a correlation peak changing due to a frequency shift. Therefore, to resolve the aforementioned problem, another solution may additionally be required.

Meanwhile, the aforementioned problem of the difficulty of distinguishing ZCZ sequences due to frequency shift is tightened under conditions where the CAZAC index is very large or not very small.

On closer examination, if “k” means an index in the frequency domain, “N” means the length of the CAZAC sequence, “M” means the CAZAC sequence, and the transmitted (Tx) signal is represented as “c (k, N, M)” , then the received (Rx) signal can be represented by the following equation 6:

[Equation 6]

,

,

where "d" means the amount of delay in the frequency domain caused by the frequency shift.

As can be seen from equation 6, if the CAZAC index “M” has a very small value, or if the CAZAC index “M” has a maximum value from all indices of Nt sequences, then the influence of the exponential function due to the frequency shift gradually decreases, so that the influence of the frequency shift on the Rx signal is gradually weakening.

If a CAZAC sequence is assigned to a cell with a frequency shift greater than a predetermined level, then the present invention allows only the root sequence to be assigned. In the case of using the CAZAC sequence with ZCZ due to the insufficient number of root sequences, the present invention allows the use of a special sequence in the CAZAC sequence, which is in the original predefined range or the last predefined range, from full indices. It should be noted that the term "predefined range" can be set in various ways depending on the characteristics of the detection system.

In the case of comparing the aforementioned method with another method, which allows not to use the ZCZ sequence in a cell with a large frequency shift, the aforementioned method increases the categories or types of available sequences, which almost eliminates the need for scheduling cells.

On closer examination, if the number of complete CAZAC sequences is Nt, as shown in FIG. 3, the sequence for use in a cell with a large frequency shift can be set by CAZAC indices 0, 1, 2, Nt-2, Nt-1 and Nt.

Meanwhile, in the case of using a CAZAC sequence for a cell with a frequency shift exceeding a predetermined level, there is no need to use only those indices that differ from the aforementioned CAZAC indices 0, 1, 2, Nt-1, Nt-2 and Nt. In order to reduce interference between the aforementioned CAZAC sequence and another sequence used for a cell with a high frequency shift, the present invention eliminates the need for the sequence index requested for a cell with a high frequency shift, if necessary, resulting in high efficiency.

Moreover, in the case of using the ZCZ sequence to provide a certain number of available sequences in a cell with a large frequency shift and / or to provide an estimate of the time delay occurring in the channel, the present invention sets the cyclic shift interval in a limited case, taking into account the false frequency (t ie, Doppler shift) caused by frequency shift. As a result, the present invention prevents the deterioration of the functional characteristics caused by the frequency shift, and the following is a detailed description.

If it is decided that a frequency shift occurs, then the frequency response of the Rx signal can be represented by Equation 6 above.

Meanwhile, Equation 6 shows that the signal value is transmitted from all neighboring subcarriers due to the frequency shift. However, in reality, a particular component, which has a strong influence on the response of the Rx signal channel, can be set to the part located on both sides of the corresponding subcarrier, while the part receives the signal of the neighboring subcarrier.

Therefore, for the first-order case only, Equation 6 can be represented by three terms, as shown in Equation 7 below:

[Equation 7]

Meanwhile, the receiving station introduces a complex conjugate number c (n) into the Rx signal, and the result of the introduction can be represented by the following equation 8:

[Equation 8]

The pulse formation function expressed by Equation 7 can be easily expressed by the raised cosine function or sinc-function.

For convenience of description, the pulse formation function is represented as constants using the constants α ₀ , α ₋₁ and α ₁ .

As equation 8 shows, the response of the Rx signal channel is observed at three points, i.e. “T” means the intended position in the time domain, “t-M” means the position shifted to the left, and “t + M” means the position shifted to the right. Obviously, the response of the channel generated at the position shifted by M, taking into account the right-to-left shift, corresponds to the false component of the Rx signal, i.e. component of the Doppler shift separation 1 subcarrier.

The above-described phenomenon in which a spurious component due to a frequency shift appears in the channel response is shown in FIG. four.

In FIG. 4 is a conceptual diagram depicting spurious components that appear in a channel response in a time domain of a received sequence due to a frequency shift, in accordance with the present invention.

If a cyclic shift is applied to a sequence used in a particular cell with a frequency shift exceeding a predetermined level, then a separate channel response appears at the intended position in the Rx channel response of the corresponding sequence, and two additional spurious components may appear in the Rx channel response of the corresponding sequence in accordance with the Doppler shift of the separation of 1 subcarrier.

Therefore, if the CS application interval is set regardless of the intended position and positions of the false components, then due to the delay in channel expansion and the delay in signal propagation, an unexpected overlap of the channel response and the false component of the Rx sequence occurs, so that a distorted overlap of the intended position and position can occur false component for different sequences using CS.

Accordingly, if a decision is made in favor of the limited case where the CS application interval is assigned in the CAZAC sequence, the present invention takes into account the spurious component generated in the channel response, so that it sets the CS application interval for a specific period within which the channel response The Rx sequence does not match the spurious in the aforementioned channel response.

In FIG. 4 illustrates an exemplary case in which a spurious component with an offset M is formed (where M = sequence index) when a CAZAC sequence is generated in the frequency domain. However, if the CAZAC sequence is generated in the time domain, then the position of the generation of the spurious component due to the Doppler shift of the spacing of 1 subcarrier can be determined in various ways.

The following is a detailed description of all CS applications used for specific areas. For convenience of description and a deeper understanding of the present invention, FIG. 5-11, it is assumed that the cyclic shift is set to T ₀ .

In FIG. 5 is a conceptual diagram showing a method of installing a new cyclic shift (CS) application unit by introducing an additional spare field into the old CS application unit, in accordance with the present invention.

In accordance with the present invention, a cyclically shifted preamble is generated according to a circuit taking into account the RACH component. However, in an environment in which there is a frequency shift associated with OFDM, the receiving station in accordance with the present invention may very well mistake the normal sequence for another sequence.

In order to eliminate the occurrence of the aforementioned problem, the present invention provides the possibility of using an additional spare field for cyclic shift, as shown in FIG. 5.

As shown in FIG. 5, delay-induced expansion characterizes delay-induced channel expansion, and two-way delay (RTD) characterizes the propagation time of a signal on a physical path between a subscriber user device (UE) and node B. If an additional spare field is used for cyclic shift, the present invention provides tuning the size of the spare field for each sequence of the sequence, so that the influence of the frequency shift when the sequence is used can be attenuated.

In the case of performing a frequency shift using an additional spare field, the choice of a cyclic shift block is determined by the function of the CAZAC sequence. In other words, in connection with the CAZAC sequence “M”, the cyclic shift unit is represented by the following equation 9:

[Equation 9]

,

,

where T ₀ means a regular cyclic shift block independent of the sequence index, and T _margin (M) means an additional spare field, used when the sequence index is M. This spare field can be selected in other ways depending on the applications of the sequence and cyclic shift.

Therefore, although it is advisable that the cyclic shear unit be at least 2M, this additional reserve field can be replaced with another reserve field depending on the CS application area. The above situation is shown in FIG. 6 and 7.

In FIG. 6 and 7 are conceptual diagrams depicting examples of the application of the additional spare field shown in FIG. 5, under conditions where the sequence index is of little importance, in accordance with the present invention.

Moreover, as shown in FIG. 6, the interval M due to the frequency shift is less than the interval T _{0 of the} cyclic shift. Even with this range, the overlap problem with other sequences can be eliminated. However, a problem may arise in evaluating information on the time delay of the transmitted sequence. Therefore, in one embodiment of the present invention, it is advisable not to use such a range when the interval M, due to the frequency shift, is less than the interval T _{0 of the} cyclic shift. However, there may be a system using this range depending on the requirements of the system.

The oblique hatched portion of FIG. 6 and 7 show the possibility of cyclic shift.

If the signal that is not affected by the frequency shift is in the t position, then the pulse affected by the frequency shift can appear at one point on the left and can appear at one point on the right. If the signal contains T ₀ as the main block of the cyclic shift, then T _margin (M) can be set equal to 2M.

An additional reserve field is applied to all indices, so that the present invention allows you to specify a cyclic shift that is highly resistant to frequency / time shifts.

However, the larger the sequence index, the higher the T _margin (M) value. As a result, the number of available cyclic shifts is reduced to “1”. To prevent a reduction in the number of cyclic shifts, the present invention provides a detailed case description with a large CAZAC index.

In FIG. 8 and 9 are a conceptual diagram showing exemplary additional spare fields shown in FIG. 5, under conditions where the sequence index is of great importance, in accordance with the present invention.

In FIG. 8 shows the case where the CAZAC index “M” is 2T ₀ -3T ₀ , and in FIG. 9 shows the case where the CAZAC index “M” is 2T ₀ -4T ₀ . Although in the case shown in FIG. 8, the main block of the cyclic shift is taken into account, a set of cyclic shifts, indicated by the oblique shaded part, can be additionally introduced into the intermediate space. The case of FIG. 9 is characterized by a wider space, and therefore, at least two cyclic shifts can be introduced into this wider space.

In FIG. 10 shows an example of a single group consisting of P sets of cyclic shifts in accordance with the present invention. As shown in FIG. 10, if, in order to generalize the above explanation, the slots indicated by oblique shaded parts are specified in the range 3M, in which the block is created by pulses, and the range M is equal to PT ₀ ~ (P + 1) T ₀ , then we can see that P is created sets of cyclic shifts.

For convenience of description, a 3M or 2M + PT ₀ block is hereinafter referred to as a group of cyclic shifts. The particular sequence to which the cyclic shift is applied contains a predetermined number of cyclic shift groups. A predetermined number of cyclic shifts can be applied to each group of cyclic shifts, so that a predetermined number of cyclic shifts can be applied to the cyclic shift component due to the Doppler shift.

In FIG. 11 is a conceptual diagram depicting a method of setting a cyclic shift application group and a cyclic shift application interval for each group in accordance with the present invention.

As shown in FIG. 11, blocks of cyclic shift groups can be defined on complete sequences, and each group of cyclic shifts can be defined, as shown in FIG. 10. Provided that the number of cyclic shift groups is G and the number of cyclic shifts for each group is P, the total number of available cyclic shifts is P * G. As shown in FIG. 11, in accordance with one embodiment of the present invention, it is assumed that the sequence is divided into groups, and each group searches for a limited available cyclic shift in each group.

In the case of applying the above scheme, all available cyclic shifts are determined in the range of indices, in which the number of groups of cyclic shifts is equal to "1". If the sequence length is N, then this range having the length N of the sequence corresponds to indices ranging from 1-N / 3 to 2N / 3-N-1. In this case, the k-th index contains the same group of cyclic shifts as the (N-k) -th index, and a set of cyclic shifts.

In FIG. 12 shows places where pulses occur due to mutual interference when the CAZAC index is in the range N / 3-N / 2 in accordance with the present invention.

The single rectangle in FIG. 12 denotes a cyclic shift unit. If the CAZAC index is greater than "N / 3", then all consecutive positions of cyclic shifts (ie, positions of cyclic shifts specified by T ₀ ) cannot be used, and they can be used in accordance with predefined rules.

The following is a description of a method for setting a limited set of cyclic shifts in accordance with one embodiment of the present invention.

In FIG. 13 is a flowchart depicting the receipt of a limited set of cyclic shifts in accordance with one embodiment of the present invention.

As shown in FIG. 13, if a limited set of cyclic shifts is set in a cell with a frequency shift exceeding a predetermined threshold value, the present invention provides a method for setting a cyclic shift taking into account the superposition of false components to avoid distorting the superposition of the desired channel response and false components.

To this end, as shown in step S1301 in FIG. 13, the present invention provides a distance “d _u ” between a response generated by a Doppler shift and a desired channel response using a given root index “u” of the sequence. Moreover, said distance corresponds to a cyclic shift generated by a Doppler shift corresponding to a spacing of 1 subcarrier.

The following is a detailed description of the variable "d _u ".

In FIG. 14 is a conceptual diagram showing a method of setting a cyclic shift variable (d _u ) corresponding to a Doppler shift associated with a subcarrier spacing 1 when a limited set of cyclic shifts is set up in accordance with the present invention.

As shown in FIG. 14 (a) if there is no influence of Doppler frequency, then the peak generated by the correlation operation at the receiving station is present at the position indicated by “1401”. Due to delay expansion and two-way delay (RTD), the peak position in the receiving station is in the N _CS block (1402) of the cyclic shift, used as the cyclic shift block, essentially selected by the system.

Meanwhile, in the presence of a Doppler frequency corresponding to a spacing of 1 subcarrier, the position of the peak caused by the correlation operation in the receiving station is selected in accordance with the sequence indices.

According to the present invention, the distance between the peak position based on the Doppler shift corresponding to the spacing Δ f 1 of the subcarrier and the ideal peak position is called “d _u ”.

In other words, in FIG. 14 (b) shows the channel response shift at the receiving station caused by the Doppler frequency −Δ f . In FIG. 14 (c) shows the channel response shift in the receiving station caused by the Doppler frequency + Δ f . Given the above phenomenon, the value of "d _u " can be considered a cyclic shift caused by the Doppler shift.

If the bounded cyclic shift is set taking into account the cyclic shift corresponding to the Doppler shift of the subcarrier spacing 1, the present invention provides control over the set bounded cyclic shift to prevent its partial coincidence with the channel response movement caused by the Doppler shift.

The present invention excludes reserved areas designated as “reserved” in FIG. 14 (b) and 14 (c) from the set cyclic shift interval so that confusion between channel responses can be prevented even when a relatively large Doppler shift occurs.

As shown above in FIG. 13 of the present invention, obtaining the secondary variables is carried out in step S1302 using the variable “d _u ” obtained in the above step S1301. Namely, according to the present invention, the number (G) of cyclic shift groups, the number (P) of cyclic shifts applicable to each group, and the length (S) of each group from the current sequences (e.g., ZC sequences) are determined.

The aforementioned secondary variables should be set in various ways, in accordance with the indices of the sequences, since the length of the group is replaced by another in accordance with the indices of the sequences. And the variable "d _u " depends on the index of the sequence, so the present invention provides a method for determining secondary variables in accordance with the range of the variable "d _u ".

In addition, in accordance with the present invention, not only the above-described group cyclic shift can be applied, but also an additional cyclic shift using a special portion that is not contained in the group of cyclic shifts within the sequence range, and a detailed description of said cyclic shift is given below.

Then, in step S1303, according to the present invention, a cyclic shift is set using the secondary variables obtained in step S1302.

A detailed description of the mathematical relationship between variables for applying cyclic shift is given below.

A limited cyclic shift is proposed in accordance with the present invention in order to prevent the generation of a strong effect of exposure to Doppler frequency.

In the following, a detailed description will be given of another offset “C _off ” of the cyclic shift other than the variable “d _u ”.

The value “C _off ” indicates the amount of displacement created by the Doppler shift.

If the amount of bias created by the Doppler shift is less than half the range of a given sequence, then this amount of bias can have the same value as the variable d _u . Otherwise, if the degree of displacement created by the Doppler shift is equal to or greater than half the range of the given sequence, then the resulting value obtained when the value “C _off ” is subtracted from the total length of the sequence corresponds to the variable d _u .

The value of “C _off ” depends on the root index of the sequence used. The preamble can be generated either in the time domain or in the frequency domain. The relationship between the values “C _off ” and “u” depends on the region generating the preamble.

If the ZC sequence is generated in the frequency domain and a cyclic shift is applied in the time domain, then the present invention allows the value “C _off ” to be derived using the following method, and its detailed description will be given below.

As an assumption, it is assumed that the signal energy is transmitted from a value transferred from an adjacent subcarrier corresponding to the Doppler frequency. It is also assumed that the transfer from the neighboring carrier occurs only in the position of the subcarrier, spaced from the current subcarrier by one empty space, and this case is called the first-order case. In this case, the Rx signal on a particular subcarrier is summed from the three terms shown in equation 10:

[Equation 10]

s (n) = p (-f _off ) c (n) + p (-w ₀ -f _off ) c (n-1) + p (w ₀ -f _off ) c (n + 1),

where the pulse formation function “p (f)” can be expressed by the raised cosine function or sinc-function. For convenience of description, if we establish the constants c ₀ , c _-1 and c ₁ , then the value of s (n) can be expressed as s (n) = c ₀ c (n) + c _-1 c (n-1) + c ₁ s (n + 1). For convenience of description, if the conjugate sequence is multiplied by the obtained value s (n), then we can obtain the following equation 11:

[Equation 11]

s (n) c ^* (n) = c ^* (n) (c ₀ c (n) + c _-1 c (n-1) + c ₁ c (n + 1)) = c ₀ + c _-1 c (n-1) c ^* (n) + c ₁ c (n + 1) c ^* (n)

If, in equation 11, “c (n) = x (n)” is expressed in terms of a CAZAC sequence, then c (n-1) c ^* (n) can be expressed using the following equation 12:

[Equation 12]

.

.

In this case, “u” means the root index, and “Nzc” means the length of the sequence.

If equation 12 is applied to equation 11, then you can see that “s (n)” consists of three signals. The first term of the value “s (n)” means a simple constant component, the second term characterizes a complex exponential wave with a frequency u / Nzc, and the third term characterizes a complex exponential wave with a frequency -u / Nzc. Therefore, the value of “C _off ” can be represented by the following equation 13:

[Equation 13]

C _{off, u} = u

Conversely, if the ZC sequence is generated from the time domain, and a cyclic shift is generated from the frequency domain, then the value “C _off ” can be calculated in the following way.

If the RACH preamble received without a frequency shift is set to r (n), then the RACH signal received with a frequency shift can be represented by the following equation 14:

[Equation 14]

.

.

Where Δω is Δω = 2πΔf / f _S , and Δf is the frequency shift in hertz (Hz), and f _S is the sampling frequency of the RACH preamble.

можно вычислить с использованием уравнения «r(n)=x_u(n)», в котором «u» указывает индекс ZC-последовательности.Autocorrelation values

can be calculated using the equation "r (n) = x _u (n)", in which "u" indicates the index of the ZC sequence.

[Equation 15]

можно вычислить с использованием If, in equation 15, “C _off , _u ” characterizes the spare field of the frequency shift, then the autocorrelation

can be calculated using

in the following equation 16:

[Equation 16]

In equation 16, “() _Nzc ” means a modular operation with respect to the value of “Nzc”. If C _{off, u} '= u * C _{off, u} is the root index associated with the shifts in the sample, and γ means the re-sample rate, which is the response to the time shift, then the value of C _{off, u} ' can be represented by the expression

C _{off, u} '= (γ-1) N _ZC .

Using equations 15 and 16, the value of γ can be represented by the expression

γ = 1 + Δ f / f _S.

The channel response position is called the main lobe, and the response position of the false component of the channel experiencing the (+/-) Doppler frequency is called the side lobe.

To clarify, the main lobe shows the position at a shift of 0, and corresponds to the normal position of the channel response in the absence of the influence of the Doppler frequency.

A positive (+) side lobe shows the position due to a positive (+) shift and corresponds to a false response position under the influence of a positive (+) Doppler frequency. A negative (-) side lobe shows the position due to a negative (-) shift and corresponds to a false response position under the influence of a negative (-) Doppler frequency.

As can be seen from equation 16, the main lobe of the autocorrelation peak arises at the position with the coordinate C _{off, u} = 0 or C _{off, u} '= 0. According to the above equation 16, a pair of side lobes arises according to the condition expressed by the following equation 17:

[Equation 17]

(u * C _{off, u} ) _Nzc = -1

Therefore, the result "u * C _{off, u} -m * Nzc" is equal to "-1", as follows from

"C _{off, u} = (m * Nzc-1) / u." In this case, “m” means the smallest integer capable of ensuring that the value C _off , _{u is} an integer. For example, if the length of the ZC sequence is 839 and the root index is 300, then the value “m” is set to 59, and the value C _{off, u is} set to 165.

In the case of using the ZC sequence in the time domain, the value of C _off can be set using the following equation 18:

[Equation 18]

C _{off, u} = (N _zc m-1) / u

In equation 18, “m” means the smallest positive number capable of ensuring that the value C _off , _{u is} an integer, and “Nzc” means the length of the ZC sequence.

All indices "u" are coprime with a value of Nzc. Therefore, there is a positive integer (u _inv = 1 / u) capable of satisfying the equation (u * u _inv = 1 mod Nzc). Therefore, the value of C _{off, u} can be conveniently represented using the following equation 19:

[Equation 19]

.

.

In equation 19, a negative sign (-) is opposite to a positive sign

(+), so that this equation can be represented as the following equation 20:

[Equation 20]

C _{off, u} = (1 / u) mod N _zc .

In short, if a CAZAC sequence is used in the frequency domain, then the index “u” of the CAZAC sequence becomes “C _off ” without any change. If the CAZAC sequence is used in the time domain, then the operation “(1 / u) mod Nzc” is performed with the index “u” of the CAZAC sequence so that the value C _off can be obtained.

In the event that the ZC sequence is used in the frequency or time domain, and the coupling feature between C _off and ZC sequences is used, then the distance “d _u ” between the main lobe and the side lobe can be expressed by the following equation 21:

[Equation 21]

.

.

The present invention provides a number of different methods for setting limited cyclic shifts, for example, a first method for setting a limited cyclic shift without using a fixed position of a cyclic shift, and a second method of setting a limited cyclic shift using a fixed position of a cyclic shift.

The first method corresponds to a limited cyclic shift without taking into account a predetermined shift position. The second method corresponds to a limited cyclic shift taking into account a predetermined shift position.

As for the first method, there are a number of different methods, namely, a method for directly using the shift value V _{a of the} limited cyclic shift, and a method for setting the cyclic shift interval using the shift value “C _va ”. Namely, the cyclically shifted sequence becomes the sequence x _u , _v (n) = x _u ((n + C _Va ) mod N _zc ), as shown in equation 4.

As for the first method, there are a number of different methods that use the decimal fraction “V _a ” for use in the cyclic shift, for example, the method of setting the interval of the cyclic shift by calculating the decimal fraction “V _a ” of the shift index.

In other words, if the cyclic shift length is set equal to Ncs, then we obtain the cyclically shifted index “x _{u, Va} (n) = x _u ((n + round (v _a N _CS )) mod N _zc )”. In this case, the “round” operator means the rounding function.

Regarding the second method, there are a number of different methods that use the integer "V _a " for use in a cyclic shift, for example, a method for setting the interval of a cyclic shift by calculating the integer "V _a " of the shift index. Namely, the cyclically shifted sequence takes the form x _{u, Va} (n) = x _u ((n + v _a N _CS ) mod N _ZC ).

Moreover, if the cyclic shift is carried out by a multiple of Ncs, then the random access preambles, each of which contains a section with a zero correlation zone (ZCZ) that does not have a correlation in the u-th root ZC-sequence, are determined by the equation x _{u, v} ( n) = x _u ((n + vN _CS ) mod N _ZC ). This definition is suitable for cells with low / medium mobility of subscribers, in which there is no problem of a strong frequency shift. However, if a limited cyclic shift is applied in a cell with high subscriber mobility, then the above definition is not suitable for a cell with high subscriber mobility. In particular, the available value of "v" is limited, and the number of available preambles with ZCZ is reduced to 1/3 of the number of preambles with ZCZ in the general case.

The following is a detailed description of the embodiments corresponding to the above cases.

Best Mode for Carrying Out the Invention

This embodiment of the present invention relates to a method for setting a limited cyclic shift, taking into account the influence of only Doppler shift, without using a fixed position of the cyclic shift.

The present invention assumes that the preamble is generated using the ZC sequence as a CAZAC sequence.

The value of "d _u " in the following equation 22 reflects a special case in which a ZC sequence is generated in the frequency domain.

[Equation 22]

.

.

In the case of generating a ZC sequence in the time domain, the value of “d _u ” can be represented using the following equation 23:

[Equation 23]

In equation 23, “m” means the smallest positive number capable of ensuring that the value “d _u ” is an integer, and Nzc means the length of the ZC sequence. Equation 23 can also be represented as the following equation 24:

[Equation 24]

Therefore, the v-th cyclic shift of the u-th root index can be given in the form x _{u, v} (n) = x _u ((n + C _v ) mod N _ZC ). Moreover, if a common cyclic shift is selected, then the value of C _v can be represented as C _v = v * N _CS . If a limited cyclic shift is selected, then the value of C _v can be obtained from equation 25.

[Equation 25]

If a limited cyclic shift is selected without a predetermined shift position, then this case is considered the first case (case 1), and its detailed description is given below.

The root of the ZC sequence with number u and the vth random access preamble, each of which has a zero correlation zone, are given by the expression “x _{u, v} (n) = x _u ((n + C _v ) mod N _ZC ) ".

In this case, “C _v ” is indicated in Equation 25 above.

In other words, in the case of unlimited sets experiencing little Doppler shift, the present invention allows you to set the cyclic shift corresponding to an integer multiple of Ncs equal to the main block of the cyclic shift.

However, in the case of unlimited sets that experience less Doppler shift, a cyclic shift corresponding to an integer multiple of Ncs can be set.

In accordance with FIG. 13, in the case of limited sets experiencing strong Doppler shift effects, the number (G) of cyclic shift groups, the number (P) of cyclic shifts applicable to each group of cyclic shifts, and the number (R) of additional cyclic shifts can be set.

The method for calculating each secondary variable can be selected differently according to the range of "d _u ", as previously indicated in FIG. 13.

, и существует G (

) групп, каждая из которых имеет длину

, и число ограниченных дополнительных циклических сдвигов задается выражением

On the interval Ncs≤d _u <(Nzc / 3), which separates the false component, the number of cyclic shifts per group is given by

, and there exists G (

) groups, each of which has a length

, and the number of bounded additional cyclic shifts is given by

, и существует G (

) групп, каждая из которых имеет длину

, и число ограниченных дополнительных циклических сдвигов задается выражением

On the interval (Ncs / 3) ≤d _u ≤ (Nzc-Ncs) / 2, separating the false component, the number of cyclic shifts per group is given by

, and there exists G (

) groups, each of which has a length

, and the number of bounded additional cyclic shifts is given by

The following is a detailed description of the principles for calculating the aforementioned secondary variables.

(1) d _u <N _CS

In FIG. 15 is a conceptual diagram representing a special case in which the variable (d _u ) is smaller than the main block N _CS to which the cyclic shift (CS) is applied, in accordance with the present invention.

The cyclic shift unit (N _CS ) is designed to take into account delayed expansion and RTD (two-way delay) that can form in the channel. Therefore, if d _{u is} less than N _CS , then the peak due to delay caused expansion and / or RTD within the range of N _CS may partially coincide with another peak caused by Doppler shift, as shown in FIG. 15. Therefore, when setting the limited cyclic shift, this embodiment does not provide for setting the cyclic shift for the case in which the value of d _{u is} less than the value of N _CS .

(2) N _CS ≤d _u <(N _Zc / 3)

In FIG. 16 is a conceptual diagram showing a method of calculating a variable establishing a cyclic shift in the range of N _CS ≤ d _u <(N _ZC / 3), in accordance with the present invention.

As shown in FIG. 16, the cyclic shift portion generated by the Doppler frequency is in the range N _CS ≤ d _u <(N _ZC / 3). In particular, the cyclic shift portion appears in the range of the sequence length located on both sides of the intended cyclic shift.

According to this embodiment, the cyclic shift portions caused by the Doppler frequency on both sides of the cyclic shift can be grouped into one group. In addition, the present invention determines how many Ncs values can be used without overlapping with other values within the range of "d _u ". The number of bounded cyclic shifts available for each group can be set to P. Namely, the value of P can be calculated using the following 26:

[Equation 26]

The distance between the specific channel response 1601 and the spurious component 1601a due to the Doppler shift is indicated by “d _u ”. The distance between the specific channel response 1601 and the other spurious component 1601a due to the Doppler shift is indicated by “d _u ”.

If P cyclic shifts are applied to each group, then the false components generated in the left section based on the channel response 1601 are contained in the range d _u , and other false components generated in the right section based on the channel 1601 response can be outside the range d _u .

Moreover, if all installation operations of false components from P channel responses generated in the right section are taken into account, the corresponding length is determined by the expression P · N _CS (1602).

Therefore, the length (S) of one cyclic shift can be equal to the sum of the length "d _u " and the length "P · N _CS ", and is expressed by the following equation 27:

[Equation 27]

The number of groups of cyclic shifts in complete sequences can be calculated by dividing the total length (N _ZC ) of the sequence by the length (S) of the group and can be expressed by the following equation 28:

[Equation 28]

Moreover, as shown in FIG. 16, a particular portion 1603 may be left with a length less than the length (S) of the group. The length of the portion “1603” corresponds to “N _ZC -G · S”, where N _ZC is the length of the complete sequence, G is the number of groups, and S is the length of the group.

If N _ZC -G · S-2d _{u is} greater than N _CS , then an additional cyclic shift can also be applied to the aforementioned portion 1603, and a detailed image thereof is shown in FIG. 16, but as for the plot "1604". Therefore, if the number of cyclic shifts that are not based on the cyclic shift group is R, the value of R can be expressed by the following equation 29:

[Equation 29]

(3) (N _Zc / 3) ≤ d _u  <(N _Zc  - N _CS ) / 2

In FIG. 17 is a conceptual diagram showing a method of calculating a variable establishing a cyclic shift in the interval (N _ZC / 3) ≤ d _u <(N _ZC -N _CS ) / 2, in accordance with the present invention.

In the region (N _ZC / 3) ≤ d _u , in contrast to the above case (2) (i.e., the above case (2) N _CS ≤ d _u <(N _ZC / 3)), the position of the channel response and false components due to the Doppler shift extend beyond the full length N _{ZC of the} sequence, so that a spurious component can occur between the channel response in the ideal case and the range of d _u .

For example, at a peak located at “1701” in FIG. 17, false components may occur at positions 1701a and 1701b through (+/-) Doppler shift. Therefore, the number of cyclic shifts applicable to one group of cyclic shifts, in this case (3), is defined by the section “N _ZC -2d _u ” (1702) located in the center of FIG. 17, so that the number P of bounded cyclic shifts applicable to each group can be calculated from the following equation 30:

[Equation 30]

In this case (3), the length S of each group of cyclic shifts can be expressed using the following equation 31:

[Equation 31]

The variable S is equal to the sum of the length of the section (N _ZC -2d _u ) 1702, and the length of the section 1703 corresponds to the length "P · N _CS ". The length of "P · N _CS " may change with a change in the number of cyclic shifts applicable to each actual group on the right side.

Moreover, in the aforementioned case (3), the number of groups of cyclic shifts in a given ZC sequence is determined by taking into account how many lengths (S, where S = the length of a particular group) will be allowed in the range d _u (1704), while in the aforementioned case ( 2) the number of groups of cyclic shifts in a given ZC sequence was determined by taking into account how many lengths (S) will be allowed on the length Nzc of the full sequence.

The space between a particular channel response and two false components for a given channel response exceeds the full sequence range, so that the present invention ensures that individual false components do not fit together within the range of _u . The number of cyclic shift groups can be expressed by the following equation 32:

[Equation 32]

And finally, the cyclic shift group is set in the range d _u (1704), as described above, and you can leave the section 1705 having a length shorter than the length of the cyclic shift group. The mentioned length of the plot 1705 corresponds to "d _u -G · S". If the length of section 1705 is greater than N _CS , then an additional cyclic shift can be applied to this length.

.Therefore, the number R of additional cyclic shifts can be represented by the expression

.

If the length (S) of each group of cyclic shifts is greater than “P”, then additional cyclic shifts corresponding to a number greater than “P” can partially be combined with the false component (+/-) in the right section. Therefore, the present embodiment may indicate the number R of additional cyclic shifts, as shown in the following equation 33:

[Equation 33]

(4) (N _Zc -N _CS ) / 2≤d _u

As shown in FIG. 17, the portion N _zc -2d _u (1702) located in the central portion must exceed N _CS so that a cyclic shift can be applied to each group. Namely, this requirement can be represented as N _ZC -2d _u > N _CS .

If the above requirement is formulated in different ways based on the value of d _u , then you can notice that the equation must be satisfied

N _ZC -N _CS > 2d _u (i.e. (N _ZC -N _CS ) / 2> d _u ). Therefore, the present embodiment does not establish a limited cyclic shift in the range of (N _ZC -N _CS ) / 2> d _u .

Below, on the basis of the above explanation for the individual intervals, a detailed description is given of only the limited set contained in Equation 25. First, the limited set according to Equation 25 can be represented using the following equation 34

[Equation 34]

C _ν = S · [ ν / P ] + ( ν mod P ) · N _CS , ν = 0,1, ..., ( P · G + R -1).

The following is a description of the individual terms used in the aforementioned cyclic shift.

In equation 34, S · [ ν / P ] indicates the starting point of each group of cyclic shifts. If the value of ν is less than the number P of cyclic shifts for each group, then S · [ ν / P ] means "0". If the value of ν is greater than the number P of cyclic shifts for each group, but less than "2P", then S · [ ν / P ] means "S", which corresponds to the length of one group of cyclic shifts.

If the value of ν is greater than “2P”, but less than “3P”, then S · [ ν / P ] means “2S”, which corresponds to the length of two groups of cyclic shifts.

The term ( ν mod P ) · N _CS indicates the position of the cyclic shift applied to each group (or the position of the additional cyclic shift). In other words, the value of ν is shifted to another position by a predetermined distance N _CS at intervals of P times.

The value of ν in equation 34 (or equation 25 containing equation 34) does not distinguish between groups or constituent groups and characterizes the total number of cyclic shifts. As a result, the total number of cyclic shifts can be represented by the expression P · G + R.

Modified Examples

The following is a description of a number of different modified examples useful in the present invention.

Although the aforementioned best embodiment relates to a special case in which there is no restriction regarding the starting point of the cyclic shift, the present invention is applicable not only to the aforementioned case, but also to other limited cases.

The following is a description of not only the aforementioned best embodiment, but also all embodiments that can be used, in general, in accordance with the present invention.

The position in which the false component arises due to the (+) Doppler frequency is indicated by the “+ shift” position, and the position in which the false component arises due to the (+) Doppler frequency is indicated by the “-shift” position.

In FIG. 18 and 19 are conceptual diagrams representing a method of reducing the number of ZCZ preamble sequences due to a false response when Nzc = 839, Ncs = 100, and d _u = 155, in accordance with the present invention.

The cyclic shift shown in FIG. 18 may start at any position. The cyclic shift shown in FIG. 19 can only be performed at a position multiple of N _CS . The value of N _CS in FIG. 18 is equal to the same value in FIG. 19, however, the initial positions of the individual cyclic shifts in FIG. 18 and 19 are different.

In conclusion, the case of FIG. 18 can create much more cyclic shifts than in the case of FIG. 19. More precisely, the case of FIG. 18 removes the restriction on the initial position of the cyclic shift, so that in this case it is possible to obtain an additional limited cyclic shift.

In FIG. 20 is a conceptual diagram showing an increase coefficient of an available limited cyclic shift after the restriction of the initial position of the cyclic shift is removed in the case of Nzc = 839, in accordance with the present invention.

Removing the constraint at the start of a cyclic shift cannot increase the complexity of the hardware.

Therefore, a limited cyclic shift without taking into account a predetermined shift position is preferable, and the aforementioned best embodiment is based on the aforementioned assumption.

However, the present invention is also applicable to a limited cyclic shift with a predetermined shift position, and therefore, the above two cases are described in the following description.

First, the case of a limited cyclic shift (i.e., case 1) not taking into account a predetermined shift position will be described below.

Equation 21 indicates the distance separating the spurious component, regardless of the generation region of the preamble. The number of available limited cyclic shifts per root ZC sequence is determined differently according to the root index and the value of N _CS , so different equations are required for use in different distance ranges separating the false components.

In particular, there are two ranges of distances separating false components in which there is no separation of false responses. The range in which a limited cyclic shift can be used is set as N _CS ≤ d _u ≤ (N _ZC -N _CS ) / 2. In this range, the range of cyclic shifts and the two ranges of false components do not have partial combinations with each other.

In this case, if the preamble is generated in the frequency domain, then the value of "d _u " is set equal to "u", i.e. d _u = u. If the preamble is generated in the time domain, then the value of "d _u " is set to "1 / u mod Nzc", i.e. d _u = 1 / u mod Nzc. The number of bounded cyclic shifts can be represented by the following equation 35:

[Equation 35]

In equation 35, “P” means the number of bounded cyclic shifts per group, “G” means the number of groups generated in the same preamble sequence, and “R” means the number of bounded additional cyclic shifts that are not based on the additional group.

The available limited cyclic shift range is defined by the expression N _CS ≤ d _u ≤ (N _ZC -N _CS ) / 2. This interval “N _CS ≤d _u ≤ (N _ZC -N _CS ) / 2” can be divided into the intervals “N _CS ≤d _u <(N _ZC / 3)” and “(N _ZC / 3) ≤d _u ≤ ( N _ZC -N _CS ) / 2 "based on Nzc / 3.

The reason why the range of distances separating the false component is divided into "N _CS ≤ d _u <(N _ZC / 3)" and "(N _ZC / 3) ≤ d _u ≤ (N _ZC -N _CS ) / 2", based on Nzc / 3, explained earlier in the text.

Therefore, N _CS ≤ d _u ≤ (N _ZC -N _CS ) / 2 is selected differently based on “Nzc / 3”. A description of the range N _CS ≤d _u <(N _ZC / 3) and the range (N _ZC / 3) ≤d _u ≤ (N _ZC -N _CS ) / 2 is given below.

If the initial position of the first group is assigned “0”, then the range of the V _a- th limited cyclic shift is defined as [C _{Va, start} , C _{Va, end} ] from equations 36 and 37.

[Equation 36]

[Equation 37]

C _{Va, end} = C _{Va, start} + Ncs-1

The false component occurs at the positions indicated by the following equations 38 and 39:

[Equation 38]

[Equation 39]

In equation 39, the term “() _Nzc ” means a modular operation.

групп. Каждая группа содержит число

ограниченных циклических сдвигов. Длина каждой группы имеет значение

. Если доступный дополнительный циклический сдвиг является положительным (+) числом, то значение R определяется выражением

.Firstly, the range N _CS ≤ d _u <(N _ZC / 3) of the distances separating the false components (i.e., the range of 1 distances separating the false components) contains the number

groups. Each group contains a number

limited cyclic shifts. The length of each group matters

. If the available additional cyclic shift is a positive (+) number, then the value of R is determined by the expression

.

In FIG. 21 is a conceptual diagram depicting an exemplary cyclic shift in the case where Nzc = 839, Ncs = 40, and d _u = 150, in accordance with one embodiment of the present invention. Each group contains three cyclic shifts, and two additional cyclic shifts exist in the remaining ranges. In this example, the total number of bounded cyclic shifts is “5”.

In one embodiment of the present invention, the number of calculated groups, the number of limited cyclic shifts per group and the length of the group are substituted into equations 36 and 37, and then the interval for applying cyclic shifts based on the above parameters is set.

, длина каждой группы определяется из выражения

, и существует G групп (где

).Then, in the range of (N _ZC / 3) ≤ d _u ≤ (N _ZC -N _CS ) / 2 distances separating the false components (i.e., in the range of 2 distances separating the false components) the number of available cyclic shifts per group determined from the expression

, the length of each group is determined from the expression

, and there are G groups (where

)

Начальная позиция Va-того ограниченного циклического сдвига вычисляется подстановкой вышеупомянутых параметров в уравнения 36 и 37.An additional cyclic shift is selected from the central part and the remaining part of the right side. In this case, the number of selected cyclic shifts should be the smallest number of cyclic shifts. Namely, if the value of R is a positive number, then the number of additional cyclic shifts is determined by the expression

The initial position of the Va-th limited cyclic shift is calculated by substituting the above parameters in equations 36 and 37.

In FIG. 22 is a conceptual diagram depicting an exemplary cyclic shift in the case where Nzc = 839, Ncs = 40, and d _u = 399, in accordance with one embodiment of the present invention.

Four groups are available, each of which contains one cyclic shift and one additional cyclic shift. In this example, the total number of cyclic shifts is 5.

According to this embodiment of the present invention, the number of calculated groups, the number of limited cyclic shifts per group and the group length are substituted into equations 36 and 37, and then, taking into account the above parameters, the interval for applying cyclic shifts is set.

In fact, the equal sign (=) between the two ranges of distances separating the false components may not matter or may have a relatively small value. For example, in the case of using a ZC sequence having a length of 839, the value of (Nzc / 3) is 279.67 (i.e., (Nzc / 3) = 279.67), and therefore the partitioned ranges Ncs≤d _u <( Nzc / 3) and (Nzc / 3) ≤d _u ≤ (Nzc-Ncs) / 2 can give the same results as the partitioned ranges Ncs≤d _u ≤ (Nzc / 3) and (Nzc / 3) <d _u ≤ (Nzc-Ncs) / 2.

The following is a description of a limited cyclic shift (i.e., case 2) that takes into account a predetermined shift position.

A method for generating a limited cyclic shift using a predetermined shift position is changed to another method. Each range of distances separating the false components contains not only G groups, each of which contains P cyclic shifts, but also the first additional cyclic shift of R ₁ groups.

In the case of using a predetermined shift position, the present invention contains a special additional cyclic shift, other than in another case, in which there is no predetermined shift position in the area of the ranges of 2 distances separating the false components.

In the region of 2 distance ranges separating the false components, the main region is formed, as a rule, in the front samples of the sequence, and the regions of the false components are formed, as a rule, in the rear samples of the sequence. However, in accordance with case 2, the main region is formed in the rear samples of the sequence, and the region of the false components are formed in the front samples of the sequence.

The second additional cyclic shift is denoted by R ₂ . The second additional cyclic shift is not formed in the range of 1 distances separating the false components. The total number of bounded cyclic shifts can be represented using the following equation 40:

[Equation 40]

In the event that the initial position of the first group is “0”, the V _a- th limited cyclic shift is set in the interval [C _{Va, start} , C _{Va, end} ], determined from equations 41 and 42:

[Equation 41]

[Equation 42]

C _{Va, end} = C _{Va, start} + Ncs-1.

The concomitant spurious component is formed at the positions given by the following equations 43 and 44:

[Equation 43]

[Equation 44]

In equations 43 and 44, the term “() _Nzc ” means a modular operation.

), P ограниченных циклических сдвигов (где

), и длина каждой группы имеет значение

Если значение R₁ является положительным (+) числом, то число первых дополнительных циклических сдвигов определяется выражением

.In the range N _CS ≤ d _u <(N _ZC / 3) of the distances separating the false components (i.e., in the range of 1 distances separating the false components) there are G groups (where

), P of bounded cyclic shifts (where

), and the length of each group matters

If the value of R ₁ is a positive (+) number, then the number of first additional cyclic shifts is determined by the expression

.

In FIG. 23 is a conceptual diagram depicting an exemplary cyclic shift in the case where Nzc = 839, Ncs = 40, and d _u = 150, in accordance with another embodiment of the present invention. In FIG. 23, each group contains three cyclic shifts and two cyclic shifts. In this example, the total number of bounded cyclic shifts is “5”.

According to this embodiment of the present invention, the number of calculated groups, the number of limited cyclic shifts per group and the group length are substituted into equations 41 and 42, and then, taking into account the above parameters, the interval for applying cyclic shifts is set.

, длина каждой группы определяется из выражения

и существует G групп (где

).Then, in the range of (N _ZC / 3) ≤ d _u ≤ (N _ZC -N _CS ) / 2 distances separating the false components (i.e., in the range of 2 distances separating the false components) the number of available cyclic shifts per group determined from the expression

, the length of each group is determined from the expression

and there are G groups (where

)

The first additional cyclic shift is calculated in the same manner as for range 1 of the distances separating the false components. If the value of R ₁ is a positive number, then the number of first additional cyclic shifts is determined by the expression

If the value of R ₁ is “0” (ie, R ₁ = 0), then the presence or absence of a second additional cyclic shift should be determined. The shape of the second additional cyclic shift is opposite to the shape of the usual cyclic shift, as shown in the last cyclic shift shown in FIG. 23.

), и выполняется определение, доступен ли интервал циклического сдвига (т.е.

).In the present invention, it is determined whether the spurious component range for the second additional cyclic shift is an available range (i.e.

), and a determination is made whether the cyclic shift interval is available (i.e.

)

In FIG. 24 is a conceptual diagram depicting an exemplary cyclic shift in the case where Nzc = 839, Ncs = 40, and d _u = 399, in accordance with another embodiment of the present invention. In FIG. 24, each group contains three cyclic shifts and does not contain the first additional cyclic shift (i.e., it contains zero first additional cyclic shift). And each group additionally contains one additional cyclic shift, in which the relative position of the main region is opposite to the relative position of the region of false components. Said second additional cyclic shift is not created when the fixed position of the cyclic shift is not applied, as shown in FIG. 22. In this example, the number of all bounded cyclic shifts is “4”.

According to this embodiment of the invention, the number of calculated groups, the number of limited cyclic shifts per group and the group length are substituted into equations 41 and 42, and then, taking into account the above parameters, the interval for applying cyclic shifts is set.

In accordance with another embodiment, a particular system with a fixed cyclic shift can determine the cyclic shift in accordance with the following method.

First, the full range of the sequence is divided by the values of the cyclic shift.

Then, according to the present invention, a range search is performed.

(± u or ± (m * Nzc-1) / u), in which the mutual interference caused by the frequency shift is generated in the first range (i.e., n = 1). In this case, there are many ranges, in each of which mutual interference occurs.

For example, if only the first mutual interference is taken into account, the maximum number of mutual interference generation ranges can be set to “4”.

Then, if the first range is not partially aligned with all ranges of mutual interference caused by the frequency shift, then the first range is set equal to the available range, and the remaining ranges caused by the frequency shift are set to a limited range (also called a forbidden range).

According to the present invention, a transition is made to the next range (i.e., n = n + 1) and a second search is made for the range in which mutual interference due to frequency shift is generated.

Although the present invention searches for a range of mutual interference generation in the n-th range, if the control range, several ranges caused by the frequency shift, the previously created available range and the preset forbidden ranges do not overlap, the present invention determines that the current range is an available range, and it is determined that several of the above ranges caused by a frequency shift and corresponding to the current range are are forbidden ranges. If the aforementioned process is repeated until the last range is reached, then the present invention makes it possible to determine a cyclic shift in the system, including a fixed cyclic shift.

According to yet another embodiment of the present invention, the aforementioned set cyclic shift interval can be applied in a mobile communication system only in a cell with high subscriber mobility, including several cells.

In this case, the present invention allows to determine whether the corresponding cell is characterized by high mobility of subscribers by determining whether the frequency shift associated with the cell exceeds a predetermined level after receiving information about the cell. In this case, a predetermined level indicates the magnitude of the frequency shift, which can be easily selected or changed by specialists in this field of technology.

In a preferred embodiment, the present invention allows the monitoring of the Node B or the UE to determine if the corresponding cell is a cell with high subscriber mobility. However, it is difficult for the UE to estimate the magnitude of the frequency shift of each of the remaining UEs in the cell. Therefore, it is more preferable that the node B determines whether the corresponding cell is a cell with high subscriber mobility by evaluating several devices of the cell UE and broadcasting the received signal over the broadcast channel.

Meanwhile, if it is determined that the corresponding cell does not have the features of a cell with high mobility of subscribers, the present invention allows the inclusion of a process for assigning a sequence not assigned to a cell with high mobility of subscribers.

The description below shows that the equations are converted to other equations with the same initial conditions as in the best embodiment, and the following is a detailed description of such transformations.

In connection with the best embodiment, the above equations can also be expressed as follows.

и

,

в диапазоне N_CS≤d_u≤(N_ZC/3) расстояний, отделяющих ложные составляющие, то значения P и G выражаются в виде P=E,

,

.If

and

,

in the range N _CS ≤ d _u ≤ (N _ZC / 3) of the distances separating the false components, the values of P and G are expressed as P = E,

,

.

и

,

в диапазоне (Nzc/3)≤d_u≤(Nzc-Ncs)/2 расстояний, отделяющих ложные составляющие, то значения P, S, G и R выражаются в виде P=F,

,

,

If

and

,

in the range (Nzc / 3) ≤d _u ≤ (Nzc-Ncs) / 2 of the distances separating the false components, then the values of P, S, G and R are expressed as P = F,

,

,

The following describes the case of a limited cyclic shift taking into account a predefined shift position (case 2) and using other equations.

The root ZC sequence with number u containing the region of zero correlation, i.e. The v-th preamble of random access is determined by the expression x _{u, v} (n) = x _u ((n + C _v ) mod N _ZC ). In this case, the value of C _v is given by equation 45:

[Equation 45]

, если R ₂=1, для соты с большой мобильностью.wherein,

if R ₂ = 1, for a cell with great mobility.

In this case, the parameters of the cell with high mobility of subscribers can be determined based on the following explanation.

, значение S определяется выражением

и значение G определяется выражением

. Первый дополнительный циклический сдвиг R1 определяется выражением

и второй дополнительный циклический сдвиг R2 определяется как R₂=0.Namely, in the range Ncs≤d _u <(Nzc / 3) of the false components, the value of P is determined by the expression

, the value of S is determined by the expression

and the value of G is determined by the expression

. The first additional cyclic shift R1 is determined by the expression

and the second additional cyclic shift R2 is defined as R ₂ = 0.

, значение S определяется выражением

и значение G определяется выражением

. Первый дополнительный циклический сдвиг определяется выражением

второй дополнительный циклический сдвиг R₂ определяется как R₂=1 в случае R₁=0 и «X-Ncs<2d_u». В данном случае, значение X определяется выражением

.In the range of (Nzc / 3) ≤d _u <(Nzc-Ncs) / 2 false components, the value of P is determined by the expression

, the value of S is determined by the expression

and the value of G is determined by the expression

. The first additional cyclic shift is determined by the expression

the second additional cyclic shift R ₂ is defined as R ₂ = 1 in the case of R ₁ = 0 and "X-Ncs <2d _u ". In this case, the value of X is determined by the expression

.

In the case of a bounded cyclic shift x _{u, v} (n) = x _u ((n + C _v ) mod N _ZC ), a method for directly using the shift amount for the νth bounded cyclic shift is described above. In addition to this method, you can use another way of applying the Va value for the Va of the limited cyclic shift so that the limited cyclic shift can be applied in the present invention. A closer look reveals that a similar cyclic shift can be created using the equation x _{u, Va} (n) = x _u ((n + round (v _a N _CS )) mod N _ZC ).

In the case of creating a cyclic shift using the aforementioned method, the principle idea is equivalent to the ideas underlying the aforementioned methods. However, different equations apply to the methods mentioned.

Below, using other equations, a description is given of the case (case 1) of a limited cyclic shift without taking into account the predefined shift position.

The index (ν) for the cyclic shift is represented by the following equation 46:

[Equation 46]

, значение S определяется выражением

, и значение G определяется выражением

, и дополнительный циклический сдвиг R определяется выражением

In the range Ncs≤d _u <(Nzc / 3) of the false components, the value of P is determined by the expression

, the value of S is determined by the expression

, and the value of G is determined by the expression

, and the additional cyclic shift R is determined by the expression

значение S определяется выражением

, значение G определяется выражением

, и значение R определяется выражением

In the range of (Nzc / 3) ≤d _u <(Nzc-Ncs) / 2 false components, the value of P is determined by the expression

the value of S is determined by the expression

, the value of G is determined by the expression

, and the value of R is determined by the expression

,

то вышеприведенное выражение можно представить другими способами. Точнее, в диапазоне Ncs≤d_u<(Nzc/3) ложных составляющих, значение P определяется выражением P=E, значение S определяется выражением

, значение G определяется выражением

, и значение R определяется выражением

If accept

,

then the above expression can be represented in other ways. More precisely, in the range Ncs≤d _u <(Nzc / 3) of the false components, the value of P is determined by the expression P = E, the value of S is determined by the expression

, the value of G is determined by the expression

, and the value of R is determined by the expression

, значение G определяется выражением

, и значение R определяется выражением

In the range of (Nzc / 3) ≤d _u ≤ (Nzc-Ncs) / 2 false components, the value of P is determined by the expression P = F, the value of S is determined by the expression

, the value of G is determined by the expression

, and the value of R is determined by the expression

Next, using other equations, a case (case 2) of a limited cyclic shift is described taking into account a predetermined shift position.

The index (ν) for the cyclic shift is represented by the following equation 47:

[Equation 47]

, значение S определяется выражением

и значение G определяется выражением

, и дополнительный ограниченный циклический сдвиг R₁ определяется выражением

In the range Ncs≤d _u <(Nzc / 3) of the false components, the value of P is determined by the expression

, the value of S is determined by the expression

and the value of G is determined by the expression

, and an additional limited cyclic shift R ₁ is determined by the expression

значение S определяется выражением

значение G определяется выражением

, и значение R₁ определяется выражением

In the range of (Nzc / 3) ≤d _u <(Nzc-Ncs) / 2 false components, the value of P is determined by the expression

the value of S is determined by the expression

the value of G is determined by the expression

, and the value of R ₁ is determined by the expression

, то значение R₂ можно представить как R₂=1. В данном случае, значение X определяется выражением

If R ₁ = 0 and

, then the value of R ₂ can be represented as R ₂ = 1. In this case, the value of X is determined by the expression

и

то в диапазоне Ncs≤d_u<(Nzc/3) ложных составляющих значение P определяется выражением P=E, значение S определяется выражением S=2F+F', значение G определяется выражением

, и значение R2 определяется выражением

If accept

and

then in the range Ncs≤d _u <(Nzc / 3) of false components, the value of P is determined by the expression P = E, the value of S is determined by the expression S = 2F + F ', the value of G is determined by the expression

, and the value of R2 is determined by the expression

, то значение R₂ можно представить как R₂=1. В данном случае, значение X определяется выражением

If R ₁ = 0 and

, then the value of R ₂ can be represented as R ₂ = 1. In this case, the value of X is determined by the expression

As described above, in accordance with the above embodiments, in the case of implementing a cyclically shifted sequence using a CAZAC sequence, the present invention allows you to specify a set of cyclic shifts that can eliminate the uncertainty of the shift caused by the frequency or time shift.

In addition, when evaluating an unsynchronized channel, the frequency shift or time offset is not tuned to this unsynchronized channel, so the present invention improves the power of this channel.

Depending on the action of the pulse shaping filter, the present invention allows you to specify a set of cyclic shifts that take into account first-order interference, second-order interference and higher-order interference.

It should be noted that the terms used in the present invention, for the most part, are defined taking into account the functions of the present invention and can be defined differently, depending on the intention of specialists in this field of technology or usual practical application. Therefore, it is advisable that the above terms are understood in view of the entire content of the description of the present invention.

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

Industrial applicability

As is apparent from the above description, the present invention makes it easy to set the cyclic shift interval (CS) at a specific non-overlapping location by taking into account the channel response for the received (Rx) sequence and the location of the spurious components of this received (Rx) sequence, even if the received ( Rx) the signal is shifted due to expansion due to channel delay or propagation delay, regardless of the category of the sequence generation area, so that the number of errors can be easily reduced to detection and false alarm frequency.

And, if a cyclic shift sequence (CS) is assigned to a cell with a frequency shift that exceeds a predetermined level, then the present invention minimizes the effect of the frequency shift on a cell with significant subscriber mobility.

The present invention relates to a first method for assigning a sequence to each cell taking into account the characteristics of a CAZAC sequence and a second method for setting a cyclic shift to be applied to the first method. Therefore, the present invention is applicable in a wireless communication system (for example, a UE device and a Node B).

Although, for clarity, a description of the preferred embodiments of the present invention is provided, it will be apparent to those skilled in the art that various modifications and additions and substitutions can be made without departing from the scope and spirit of the invention defined in the attached claims.

Claims (24)

1. A method for adjusting a cyclic shift to be applied to a given sequence to counteract the effect of a high Doppler frequency higher than a predetermined value, comprising the steps of:
receive the first variable (d _u ) cyclic shift corresponding to the Doppler shift of the separation of one subcarrier, using the root index (u) of this sequence;
secondary variables are obtained using the first variable (d _u ), the secondary variables comprising the number of groups (G) formed by grouping this sequence, the length of each group (S), and the number of applicable cyclic shift values (P) for each group; and set the magnitude of the cyclic shift, which should be applied to this sequence in accordance with the secondary variables. 2. The method according to claim 1, in which the secondary variables additionally contain a number of additional cyclic shifts that are applicable to this sequence, not based on group (R). 3. The method according to claim 1 or 2, in which this sequence is a sequence of Zadova-Chu (ZC) and
the first variable is obtained according to the equation

where “u” indicates the root index of the ZC sequence and “N _ZC ” corresponds to the length of the ZC sequence. 4. The method according to claim 3, in which the secondary variables are obtained differently in accordance with the range of the first variable (d _u ) and the range of the first variable is partitioned using a criterion corresponding to 1/3 of the length of the sequence (N _ZC / 3). 5. The method according to claim 4, in which:
if the range of the first variable (d _u ) is N _CS ≤ d _u <(N _ZC / 3), then the secondary variables are obtained from the equations

where “N _CS ” is a predetermined cyclic shift parameter, “P” corresponds to the number of cyclic shifts per group, “S” corresponds to the length of each group, “G” corresponds to the number of groups, and “R” corresponds to the number of additional cyclic shifts. 6. The method according to claim 4, in which:
if the range of the first variable (d _u ) is (N _ZC / 3) ≤d _u ≤ (N _ZC -N _CS ) / 2, then the secondary variables are obtained from the equations

where “N _CS ” is a predetermined cyclic shift parameter, “P” corresponds to the number of cyclic shifts per group, “S” corresponds to the length of each group, “G” corresponds to the number of groups, and “R” corresponds to the number of additional cyclic shifts. 7. The method according to claim 5 or 6, wherein said cyclic shift setting (C _ν ) is performed in accordance with an equation of the form

8. The method of claim 1, wherein the sequence is for generating a random access preamble. 9. A method for adjusting a cyclic shift to be applied to a given sequence, comprising the steps of:
determining whether to establish a cyclic shift in accordance with limited sets limited due to Doppler shift; and
establish a cyclic shift, which should be applied to this sequence, taking into account the cyclic shift corresponding to the Doppler shift of the separation of one subcarrier, when it is determined that the cyclic shift should be set in accordance with limited sets. 10. The method according to claim 9, in which:
when it is determined that the cyclic shift should be set in accordance with limited sets, said setting of the cyclic shift to be applied to the sequence comprises the steps of:
get the first variable (d _u ) showing the cyclic shift corresponding to the Doppler shift of the spacing of one subcarrier using the root index (u) of this sequence;
secondary variables are obtained containing the number of groups (G) contained in a given sequence, the length (S) of each group, the number (P) of cyclic shifts per group using the first variable (d _u ), and the number of additional cyclic shifts that apply to this sequence, not based on group (R); and establish a cyclic shift, which should be applied to this sequence in accordance with the secondary variables. 11. The method according to claim 10, in which this sequence is a Zadov-Chu (ZC) sequence and the first variable is obtained from the equation

where “u” indicates the root index of the ZC sequence and “N _ZC ” corresponds to the length of the ZC sequence. 12. The method according to claim 11, in which the secondary variables are obtained differently, in accordance with the range of the first variable (d _u ) and the range of the first variable is broken using the criterion corresponding to 1/3 of the length of the sequence (N _ZC / 3). 13. The method according to item 12, in which:
if the range of the first variable (d _u ) is N _cs ≤ d _u <(N _zc / 3), then the secondary variables are obtained according to the equations

where “N _CS ” is a predetermined cyclic shift parameter, “P” corresponds to the number of cyclic shifts per group, “S” corresponds to the length of each group, “G” corresponds to the number of groups, and “R” corresponds to the number of additional cyclic shifts. 14. The method according to item 12, in which:
if the range of the first variable (d _u ) is (N _ZC / 3) ≤d _u ≤ (N _ZC -N _CS ) / 2, then the secondary variables are obtained from the equations

where “N _CS ” is a predetermined cyclic shift parameter, “P” corresponds to the number of cyclic shifts per group, “S” corresponds to the length of each group, “G” corresponds to the number of groups, and “R” corresponds to the number of additional cyclic shifts. 15. The method according to item 13 or 14, in which the cyclic shift (With _ν ) is performed according to the following equation:

16. The method of claim 9, wherein the sequence is for generating a random access preamble. 17. A method for transmitting a random access preamble by adjusting a cyclic shift to be applied to a given sequence in a transmitter, comprising the steps of:
(a) get the variable d _u from the equation

where "u" indicates the root index of the sequence and "N _ZC " corresponds to the length of the sequence; (b) get the variables G, S, P and R from the equations

when the range of the first variable (d _u ) is N _CS ** d _u <(N _ZC / 3), and the variables G, S, P and R are obtained from the equations

when the range of the first variable (d _u ) is (N _ZC / 3) ≤ d _u ≤ (N _ZC -N _CS ) / 2, wherein “N _CS ” is a predetermined cyclic shift parameter;
(c) establish a cyclic shift (C _** ) according to the equation

moreover, limited sets are sets of cyclic shifts limited due to Doppler shift, and unlimited sets are sets of cyclic shifts not limited due to Doppler shift; and
(d) transmit the random access preamble to the receiver by using the established cyclic shift. 18. A method for transmitting a random access preamble using a cyclic shift, comprising the steps of:
obtaining a root index (u) of a sequence for a random access preamble from system information;
establish a cyclic shift that should be applied to the sequence, and the cyclic shift that should be applied to the sequence is set taking into account the cyclic shift corresponding to the Doppler shift of the spacing of one subcarrier, when it is determined that the cyclic shift should be set in accordance with limited sets limited due to Doppler shear;
generate a sequence in accordance with the root index (u) with the established cyclic shift and
transmit the cyclic-shifted sequence as a random access preamble. 19. The method according to p, in which:
when it is determined that the cyclic shift should be set in accordance with limited sets, said setting of the cyclic shift, which should be applied to the sequence, comprises the steps of:
get the first variable (d _u ) indicating the cyclic shift corresponding to the Doppler shift of the separation of one subcarrier, using the root index (u) of this sequence;
secondary variables are obtained containing the number of groups (G) contained in the sequence, the length (S) of each group, the number (P) of cyclic shifts per group using the first variable (d _u ) and the number of additional cyclic shifts that are applicable to the sequence, not based on group (R); and establish a cyclic shift, which should be applied to the sequence, in accordance with the secondary variables. 20. The method according to claim 19, in which this sequence is a Zadov-Chu (ZC) sequence and the first variable is obtained according to the equation

where “u” indicates the root index of the ZC sequence and “N _ZC ” corresponds to the length of the ZC sequence. 21. The method according to claim 20, in which the secondary variables are obtained differently, in accordance with the range of the first variable (d _u ) and the range of the first variable is divided using the criterion corresponding to 1/3 of the length of the sequence (N _ZC / 3). 22. The method according to item 21, in which:
if the range of the first variable (d _u ) is N _CS ≤ d _u <(N _ZC / 3), then the secondary variables are obtained from the equations

where “N _CS ” is a predetermined cyclic shift parameter, “P” corresponds to the number of cyclic shifts per group, “S” corresponds to the length of each group, “G” corresponds to the number of groups, and “R” corresponds to the number of additional cyclic shifts. 23. The method according to item 21, in which:
if the range of the first variable (d _u ) is (N _ZC / 3) ≤d _u ≤ (N _ZC -N _CS ) / 2, then the secondary variables are obtained from the equations

where “N _CS ” is a predetermined cyclic shift parameter, “P” corresponds to the number of cyclic shifts per group, “S” corresponds to the length of each group, “G” corresponds to the number of groups, and “R” corresponds to the number of additional cyclic shifts. 24. The method according to item 22 or 23, in which the cyclic shift (C _ν ) is performed according to the following equation

Images