JP5421444B2 - Method for generating random access preamble in wireless communication system - Google Patents

Description

  The present invention relates to wireless communication, and more particularly to a method for generating a random access preamble in a wireless communication system.

WCDMA (Wideband Code Division Multiple Access) 3GPP (3 rd Generation Partnership Project) mobile communication system based on radio access technology is extensively deployed worldwide. High Speed Downlink Packet Access (HSDPA), which can be defined as the first evolutionary stage of WCDMA, provides 3GPP with a highly competitive wireless connection technology in the mid-term future. However, as wireless access technology development continues to compete with the requirements and expectations of users and operators continuously increasing, new technology evolution in 3GPP is required to be competitive in the future. .

  Orthogonal Frequency Division Multiplexing (hereinafter, OFDM) system that can reduce the inter-symbol interference effect to a low complexity, one of the systems considered in the system after three households It is. In OFDM, data symbols input in series are converted into N parallel data symbols and transmitted on N subcarriers that are separated from each other. The subcarriers should maintain orthogonality in the frequency dimension. Each orthogonal channel may experience frequency selective fading independent of each other, and the interval between transmitted symbols may be increased to minimize intersymbol interference. Orthogonal Frequency Division Multiple Access (hereinafter, referred to as OFDMA) realizes multiple connections by providing each user with a part of subcarriers that can be used independently in a system that uses OFDM as a modulation scheme. Multiple connection method. In general, OFDMA provides each user with a frequency resource called a subcarrier, and each frequency resource is provided independently to a plurality of users and does not overlap each other. Eventually, frequency resources are allocated mutually exclusively for each user.

  In order to transmit or receive data packets, it is necessary to transmit control information. For example, the uplink control information includes an ACK (Acknowledgement) / NACK (Negative-Acknowledgement) signal, which is a response to downlink data transmission, a CQI (Channel Quality Indicator) indicating downlink channel quality, and a PMI (Precoding Index). RI (Rank Indicator) and the like. In addition, transmission of a random access preamble is also necessary to perform a random access process.

  A sequence is widely used to transmit uplink control information and random access preamble. The sequence is transmitted through a control channel or a random access channel in the form of a spreading code, a terminal identifier, and a signature.

  FIG. 1 is an exemplary diagram illustrating a method for performing a random access process in a WCDMA system. The random access process is used for the terminal to acquire radio resources for time synchronization with the network or for transmitting uplink data.

  Referring to FIG. 1, a terminal transmits one access slot and one preamble via a physical random access channel (PRACH), which is an uplink physical channel. The preamble is transmitted during an access slot having a length of 1.33 ms, and one of the 16 preambles is selected and transmitted.

  When the terminal receives the preamble, the base station transmits a response via an AICH (Acquisition Indicator Channel) that is a downlink physical channel. The base station transmits a positive response (ACK) or a negative response (Not-Acknowledgement; NACK) to the terminal via the AICH. If the terminal receives an ACK, the terminal transmits a message having a length of 10 ms or 20 ms using an OVSF (Orthogonal Variable Spreading Factor) code corresponding to the transmitted preamble. If the terminal receives NACK, it transmits the preamble again after an appropriate time. If the terminal cannot receive a response corresponding to the transmitted preamble, the terminal transmits a new preamble with a power higher by one step than the previous preamble after the determined access slot.

  After receiving 16 preambles (that is, sequences) that can be used by the base station from the base station, the terminal uses one sequence selected from the assigned sequences as a preamble in the random access process. If the base station transmits information on all possible sequences, the signaling overhead becomes too large. Therefore, the base station generally designates a set of sequences in advance and transmits the sequence set index to the terminal. To do. For this purpose, the terminal and the base station must store all sequence sets according to the index of each sequence set in a buffer. This is because if the number of sequences belonging to a set of sequences becomes large or the number of sets of sequences becomes large, it can be a burden.

  In order to increase the data detection performance in the receiver and increase the capacity of the terminal, the sequence must have certain correlation and CM (cubic metric) characteristics. For example, this means that a sequence belonging to a set of sequences used in a random access process must have a certain level of correlation and CM characteristics that are guaranteed to a certain level. In particular, a sequence used in a high speed environment in which the terminal moves to a speed of 30 km / h or higher and a sequence used in a low speed environment need to be used differently to ensure sequence characteristics due to factors such as the Doppler effect. There is.

  There is a need for a method that can guarantee the characteristics of a sequence used for transmission of uplink control information with less signaling overhead.

  The present invention provides a method for generating a logical index of a primordial ZC (Zadoff-Chu) sequence so that sequence generation is facilitated.

  The present invention also provides a method for performing a random access process in a wireless communication system using a logical index of a primitive ZC sequence.

  The present invention also provides a method for generating a random access preamble using a logical index of a primitive ZC sequence.

  In one aspect, a method for generating a logical index of a primitive ZC (Zadoff-Chu) sequence is provided. The method divides a logical index of a plurality of primitive ZC (Zadoff-Chu) sequences into one or more subgroups according to a predetermined cyclic shift parameter, and the subgroup includes at least one primitive ZC ( Including a logical index of a Zadoff-Chu) sequence, and mapping a primitive index of a Zadoff-Chu sequence within the subgroup to a continuous logical index.

  In another aspect, a method for performing a random access process in a wireless communication system is provided. The method selects a random access preamble from a plurality of random access preambles, wherein the plurality of random access preambles are generated from available cyclic shifts of a source ZC sequence having a continuous logical index, and the continuous logic A local index is mapped to a source index of the source ZC sequence, includes transmitting the selected random access preamble and receiving a random access response including an identifier of the selected random access preamble.

  In another aspect, a method for performing a random access process in a wireless communication system includes transmitting a plurality of random access by transmitting a pre-designated cyclic shift parameter and a source logical index for generating a plurality of random access preambles. Receiving a random access preamble selected from a preamble, wherein the plurality of random access preambles are available cycles of a source ZC sequence having at least one continuous logical index in the source logical index and the source logical index; Transmitting a random access response generated from the shift and including an identifier of the random access preamble.

  In another aspect, a method for generating a random access preamble is provided. The method generates a plurality of random access preambles from a first primitive ZC sequence having a first primitive index mapped to a first logical index in order of increasing cyclic shift, and is predetermined from the first primitive ZC sequence. Generating a plurality of additional random access preambles in order of increasing cyclic shift from a second source ZC sequence having a second source index mapped to a second logical index when a predetermined number of random access preambles are not generated And the second logical index is continuous to the first logical index.

  In another aspect, a method for generating a random access preamble is provided. The method receives a source logical index information and a primitive ZC sequence having a continuous logical index starting from the source logical index until a predetermined number of random access preambles are obtained. A plurality of random access preambles are generated in order of increasing cyclic shift, and the continuous logical index is mapped to the original index of the original ZC sequence.

  Using continuous logical indexes, a random access preamble set with similar physical characteristics can be generated. Control signaling for generating the random access preamble can be minimized. Random access failures can be reduced in a high-speed environment, and efficient cell planning can be performed.

FIG. 3 is an exemplary diagram illustrating a method for performing a random access process in a WCDMA system. It is a block diagram which shows a radio | wireless communications system. It is a flowchart which shows the sequence production | generation method based on one Example of this invention. 6 shows CM characteristics and maximum supported cell radius characteristics with a physical index according to an embodiment of the present invention. 10 shows CM characteristics and maximum support cell radius characteristics with a logical index according to an embodiment of the present invention. 10 shows CM characteristics and maximum support cell radius characteristics with a logical index according to another embodiment of the present invention. 10 shows CM characteristics and maximum support cell radius characteristics with a logical index according to another embodiment of the present invention. 10 shows CM characteristics and maximum support cell radius characteristics with a logical index according to another embodiment of the present invention. 10 shows CM characteristics and maximum support cell radius characteristics with a logical index according to another embodiment of the present invention. 10 shows CM characteristics and maximum support cell radius characteristics with a logical index according to another embodiment of the present invention. 10 shows CM characteristics and maximum support cell radius characteristics with a logical index according to another embodiment of the present invention. 10 shows CM characteristics and maximum support cell radius characteristics with a logical index according to another embodiment of the present invention. 10 shows CM characteristics and maximum support cell radius characteristics with a logical index according to another embodiment of the present invention. 10 shows CM characteristics and maximum support cell radius characteristics with a logical index according to another embodiment of the present invention. FIG. 6 illustrates the number of restricted cyclic shifts available per logical index with Ncs for CM mapping according to one embodiment of the present invention. FIG. FIG. 6 illustrates the number of limited cyclic shifts available per logical index with Ncs for maximum supported cell size mapping according to one embodiment of the present invention. FIG. FIG. 6 illustrates the number of limited cyclic shifts available per logical index with Ncs for hybrid mapping according to one embodiment of the present invention. FIG. 4 illustrates an example of a logical index assigned to a cell for CM mapping according to an embodiment of the present invention. FIG. 6 illustrates an example of a logical index assigned to a cell for maximum support cell size mapping according to an embodiment of the present invention. FIG. FIG. 6 illustrates an example of a logical index assigned to a cell for maximum support cell size mapping according to an embodiment of the present invention. FIG. 6 illustrates a method for searching a logical index according to CM characteristics according to an embodiment of the present invention. 6 illustrates a method for searching a logical index according to CM characteristics according to another embodiment of the present invention. 6 illustrates a method for searching a logical index according to CM characteristics according to another embodiment of the present invention. 6 shows CM characteristics associated with a physical root index according to an embodiment of the present invention. 10 shows CM characteristics and maximum support cell radius characteristics with a logical index according to another embodiment of the present invention. 10 shows CM characteristics and maximum support cell radius characteristics with a logical index according to another embodiment of the present invention. A process of grouping CM alignments into two groups is shown. The process of grouping the alignments with the maximum support Ncs characteristic within each group into Ncs groups is shown. The process of aligning according to CM characteristics within each Ncs group is shown. 5 is a flowchart illustrating a random access process according to an embodiment of the present invention. It is a block diagram which shows the element of the terminal with which the Example of this invention is applied.

  FIG. 2 is a block diagram illustrating a wireless communication system. Wireless communication systems are widely deployed to provide various communication services such as voice and packet data.

  Referring to FIG. 2, the wireless communication system includes a terminal (10; User Equipment, UE) and a base station (20; Base Station, BS). The terminal (10) may be fixed or mobile, and may be any other term such as MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), wireless device (wireless device), etc. Sometimes called. The base station (20) generally refers to a fixed station that communicates with the terminal (10), such as a Node B (Node-B), a BTS (Base Transceiver System), an access point (Access Point), and the like. , Sometimes called other terms. One base station (20) can have one or more cells.

  Hereinafter, the downlink means communication from the base station (20) to the terminal (10), and the uplink means communication from the terminal (10) to the base station (20). . On the downlink, the transmitter is part of the base station (20) and the receiver is part of the terminal (10). On the uplink, the transmitter is part of the terminal (10) and the receiver is part of the base station (20).

  There are no restrictions on the multiple access technique applied to the wireless communication system. CDMA (Code Division Multiple Access), TDMA (Time Division Multiple Access), FDMA (Frequency Division Multiple Access), SC-FDMA (Single-Carrier FDMA), and SC-FDMA (Single-Carrier FDMA). can do. For clarity of explanation, an OFDMA-based wireless communication system will be described below.

  OFDM (Orthogonal Frequency Division Multiplexing) uses a plurality of orthogonal subcarriers. OFDM uses orthogonality characteristics between IFFT (inverse fast Fourier transform) and FFT (fast Fourier transform). In the transmitter, data is transmitted by performing IFFT. The receiver restores the original data by performing FFT on the received signal. The transmitter uses IFFT to combine multiple subcarriers and the receiver uses corresponding FFT to separate multiple subcarriers. According to OFDM, in a frequency selective fading environment of a wideband channel, the complexity of a receiver is reduced, and channel characteristics that are different between subcarriers are utilized to perform selective scheduling in the frequency domain. Therefore, frequency efficiency can be improved. OFDMA (Orthogonal Frequency Division Multiple Access) is a multiple connection scheme based on OFDM. According to OFDMA, the efficiency of radio resources can be improved by assigning different subcarriers to multiple users.

  The control information is described below.

  The control information includes ACK (Acknowledgement) / NACK (Negative-Acknowledgement) signals indicating the presence / absence of retransmission, CQI (Channel Quality Indicator) indicating downlink channel quality, and random access preamble (random access) for the random access process. In addition, there are various types such as MIMO (Multiple Input Multiple Output) control information such as PMI (Precoding Matrix Index) and RI (Rank Indicator).

  An orthogonal sequence may be used for transmission of control information. An orthogonal sequence refers to a sequence having excellent correlation characteristics. As an example of the orthogonal sequence, there is a CAZAC (Constant Amplitude Zero Auto-Correlation) sequence.

  When describing a ZC (Zadoff-Chu) sequence that is one of the CAZAC sequences, the k-th element c (k) of the original ZC sequence having a root index M is as follows: Can be represented.

Here, N is the length of the ZC sequence, the index M is a natural number equal to or less than N, and M and N are mutually prime numbers (prime). If N is a prime number, the number of primitive indexes (rootindex) of the ZC sequence is N-1.

  The ZC sequence c (k) has the following three characteristics.

Equation 2 means that the size of the ZC sequence is always 1, and Equation 3 means that the autocorrelation of the ZC sequence is displayed in the Dirac-delta function. Here, the automatic correlation is based on a circular correlation. Equation 4 means that the cross correlation is always a constant.

  In a wireless communication system, if a cell is partitioned through a ZC sequence root index, the terminal must know the source index or group of source indexes available in the cell. In addition, the base station must broadcast available primitive indexes or groups of primitive indexes to the terminal.

When the length of the ZC sequence is N, there are as many prime indexes as the number of relative primes smaller than N. When N is a prime number, the number of primitive indexes is N-1. In this case, the base station needs ceil (log ₂ (N-1)) bits to inform the terminal of any one of the N-1 primitive indexes. Hereinafter, ceil (n) represents a minimum integer larger than n.

  Each cell may use a different number of primitive indexes according to the cell radius. When the cell radius is increased, the number of ZC sequences that can maintain orthogonality through cyclic shift due to propagation delay or roundtrip delay and / or delay spread. Can be reduced. That is, as the cell radius increases, the number of cyclic shifts available for the corresponding primitive index can be reduced even if the length of the ZC sequence is constant. In this manner, sequences created by cyclic shift using the primitive index are orthogonal to each other, and are therefore also referred to as ZCZ (zero correlation zone) sequences. Since the minimum number of ZC sequences allocated to the terminal for each cell must be guaranteed, when the cell radius increases, the minimum number of ZC sequences can be ensured by increasing the number of primitive indexes used in the cell. it can.

A group of primitive ZC indexes that can be used for each cell is called Ri, and it is assumed that all M primitive ZC index groups are set. This is R ₁ , R ₂ ,. . . It can be represented in _{R M.} If R _i = 10, it can be said that the cell in which R _i is set uses 10 primitive ZC indexes. Hereinafter, according to the cell radius, N = 839, M = 7, R ₁ = 1, R ₂ = 2, R ₃ = 4, R ₄ = 8, R ₅ = 16, R ₆ = 32, R ₇ = 64 If the cell radius is large, the minimum ceil (log ₂ (7)) + ceil (log ₂ (838/64)) = 7 bits is required to transmit control information, and the cell radius is small. The maximum ceil (log ₂ (7)) + ceil (log ₂ (838/1)) = 13 bits is required.

  With the development of wireless communication, demands for higher transmission rates are increasing, and the number of cells having a small cell radius is increasing. Since a cell having a small cell radius uses only one primitive ZC index, more bits are required for transmission of control information, which may cause signaling overhead. Therefore, a technique for reducing the number of bits required for signaling in all cells is necessary. In particular, it may be more important to reduce the number of signaling bits in a cell having a small cell radius.

  FIG. 3 is a flowchart illustrating a sequence generation method according to an embodiment of the present invention.

  Referring to FIG. 3, a plurality of primitive ZC sequences are divided into one or more subgroups according to a pre-designated cyclic shift parameter (S110). The subgroup includes at least one primitive ZC sequence. When the cyclic shift parameter is Ncs, the primitive ZC sequence has a zero correlation zone of length Ncs-1. The cyclic shift parameter is a parameter for determining the cyclic shift unit of the original ZC sequence, and the subgroups can be ordered according to the cyclic shift parameter. Since the effect of the Doppler frequency appears greatly in a high-speed environment, the cyclic shift unit is obtained using the cyclic shift parameter according to each maximum support cell radius and the Doppler shift of the detection stage. The cyclic shift unit is a unit for cyclically shifting one primitive ZC sequence. The cyclic shift parameter of the original ZC sequence is smaller than or the same as the cyclic shift parameter of the subgroup of the original ZC sequence. The cyclic shift of the original ZC sequence has a value larger than the cyclic shift parameter of the original ZC sequence.

  Primitive ZC sequences are aligned according to CM (Cubic Metric) within the subgroup (S120). Alignment with CM characteristics refers to alignment according to the CM characteristics of the ZC sequence associated with the combination of primitive ZC indexes. Metrics for aligning primitive ZC sequences within subgroups include not only CM but also cross-correlation, PAPR (Peak-to-Average Power Ratio), and Doppler frequency (Doppler frequency), etc. Can be used. Alignment with the cross-correlation property refers to alignment according to the cross-correlation property of the ZC sequence with the combination of the original ZC index. Alignment with PAPR characteristics refers to alignment according to the PAPR characteristics of the ZC sequence associated with the combination of the original ZC index. The alignment according to the Doppler frequency characteristic refers to alignment according to the degree of robustness to the Doppler frequency of the original index.

  A gain can be obtained by using an index having a strong Doppler frequency for a cell having a relatively high speed mobility (high mobility cell or high speed cell). When using a restricted cyclic shift with a high mobility cell, a maximum supported cell radius or a maximum supported cyclic characteristic according to a maximum supported cell radius Can do. By comparing the maximum supported cyclic shift parameter of each primitive ZC cyclic sequence with a predetermined cyclic shift parameter and dividing it into subgroups, the primitive ZC sequences belonging within the subgroup have similar characteristics.

  A physical root index of a primitive ZC sequence belonging to one subgroup is mapped to a continuous logical index (S130). The physical primitive index refers to a primitive index of a ZC sequence that a base station and / or a terminal actually uses for transmission of control information and a random access preamble. A logical index is a logical primitive index to which a physical primitive index is mapped.

  As described above, when the original ZC sequence is divided into subgroups according to a pre-designated cyclic shift parameter and a continuous logical index is allocated within the subgroup, the base station may have at least one logical index assigned to the terminal. Only information about multiple ZC sequences having similar characteristics can be notified. For example, if the primitive ZC sequence is aligned according to CM in the subgroup and the terminal is informed of one logical index, the terminal may start from the physical original index to which the received one logical index is mapped. Is generated. If the number of ZC sequences generated from one logical index (eg, the number of usable cyclic shifts of the ZC sequence) is insufficient, the physical mapped to the logical index adjacent to the received logical index A new primitive ZC sequence is generated from the target primitive index. Since adjacent logical indexes have similar CM characteristics, even if only one logical index is given, the terminal can generate a plurality of ZC sequences having similar CM characteristics.

<Example of ordering with CM characteristics>
FIG. 4 illustrates CM characteristics and maximum supported cell radius characteristics according to a physical index according to an embodiment of the present invention. FIG. 5 shows a CM characteristic and a maximum support cell radius characteristic with a logical index according to an embodiment of the present invention. FIG. 6 shows a CM characteristic and a maximum support cell radius characteristic with a logical index according to another embodiment of the present invention.

When N is the length of the ZC sequence, the physical primitive index in FIG. 4 is U _P = 1, 2, 3,. . . , N-3, N-2, and N-1. 5 selects and re-arranges the logical indexes one by one from before and after the physical primitive index of FIG. 4 to make the logical indexes U _L = 1, N−1, 2, N−2, 3, N−3, 4 ,. . . It is the result expressed as follows. FIG. 6 shows the result of aligning the physical index of FIG. 4 with CM values corresponding to the logical index.

  Table 1 shows an example of CM-based ordering of physical and logical indexes.

After the physical primitive index is aligned according to the CM characteristics, the CM characteristics of the ZC sequence corresponding to the contiguous logical index can be similarly maintained by mapping to the logical index, and the CM-based cell design (CM based cell planning). A base station can design a CM-based cell in a power limited environment such as a cell having a poor channel environment or a cell having a large cell radius. In addition, the base station can use an index with good CM characteristics as a dedicated preamble in the case of a handover or the like. A terminal having a poor channel environment already uses its maximum power, and thus it is difficult to obtain a power ramping effect. The base station can increase the detection probability by assigning an index with good CM characteristics to such a terminal.

<Example of alignment with maximum support cell radius characteristics>
FIG. 7 shows a CM characteristic and a maximum support cell radius characteristic with a physical primitive index according to another embodiment of the present invention. FIG. 8 shows a CM characteristic and a maximum support cell radius characteristic with a logical index according to another embodiment of the present invention. FIG. 9 shows a CM characteristic and a maximum support cell radius characteristic with a logical index according to another embodiment of the present invention.

Referring to FIGS. 7 to 9, FIG. 7 is an alignment of the ZC sequence used in FIG. 4 according to the maximum support cell radius. When N is the length of the ZC sequence, the physical index U _P = 1, 2, 3,. . . It is obtained by realigning the physical root indexes to N-3, N-2, N-1 a _{(1 / U P) mod N} . At this time, to the ZC sequence indexes generated in the time domain to the (1 / U P) _mod N is to map the ZC sequence indexes generated in the frequency domain. In other words, such a transformation means rearranging the ZC sequence index characteristic generated in the time domain to the ZC sequence index generated in the frequency domain. Figure 8 is a physical index _{U P} to _{(1 / U P) mod 1} N indexes are converted after index conversion simply to, N-1,2, N-2,3 , N-3,4 ,. . . This is the result of reordering one by one from the front and back. FIG. 9 shows the result of accurate realignment with the maximum support cell radius corresponding to the physical index.

  Table 2 shows an example of maximum supported cell radius-based ordering.

The method of aligning according to the maximum support cell radius may be applied when using a restricted cyclic shift in a high speed cell environment. When using limited cyclic shift, the value of cyclic shift (Ncs) that can be supported by the index can be changed. As shown in FIG. 4, when the physical primitive index is used as it is, it is difficult to use a physical index that is continuous in a single cell. Such an effect may cause a problem that an index that does not overlap every cell in the entire network should be assigned. That is, the reuse factor of the sequence is reduced and the cell design becomes difficult. Therefore, such a problem can be solved by using a logical index aligned according to the maximum support cell radius characteristic. However, gain in the CM characteristic may not be obtained when aligning according to the maximum support cell radius characteristic.

<Example of alignment with CM characteristics and maximum support cell radius characteristics>
The alignment according to the CM characteristic and the alignment with the maximum support cell radius characteristic may exhibit mutually contradictory characteristics. A method capable of having all the gains of the CM characteristic and the maximum support cell radius characteristic will be described.

The method of aligning various characteristics in accordance with the following procedure follows.
1. Align the entire index according to specific characteristics.
2. Divide the whole index into sections by related values (grouping).
3. Within each interval (or group), the indices within the interval (or group) are aligned according to other characteristics.
4). Repeat steps 2 and 3 At this time, dividing the section in stage 2 may be related to a previously partitioned section, or a new rule may be applied without being related to a previously partitioned section.

  FIG. 10 shows a CM characteristic and a maximum support cell radius characteristic with a logical index according to another embodiment of the present invention. The alignment according to the maximum support cell radius characteristic and the setting of the section of the maximum support cell radius according to the specific value (Ncs) are shown. FIG. 11 shows alignment with CM characteristics within the section set in FIG.

  Referring to FIGS. 10 and 11, first, the entire index is aligned according to the maximum support cell radius, and then the section is divided according to the cyclic shift parameter (Ncs) or the maximum support cell radius value. The cyclic shift parameter (Ncs) is a parameter for obtaining a cyclic shift unit supported per ZC sequence.

  Table 3 shows an example of the cyclic shift parameter (Ncs).

When the characteristics of the physical index are as shown in FIG. 4, when the whole index is aligned according to the maximum support cell radius, it is shown in FIG. FIG. 9 is divided into the maximum support cell radius values for the cyclic shift parameter (Ncs) in Table 3 as shown in FIG. Here, the value of “No guard sample” was used.

  Alignment according to CM characteristics within each divided section is shown in FIG. At this time, the relationship between the physical index and the logical index is applied with hybrid ordering considering all CMs and maximum support cell radii in Table 4.

A plurality of sequences are divided into a plurality of subgroups according to the cyclic shift parameter (Ncs), and are arranged in the subgroup according to the CM characteristics (order). Multiple subgroups can be aligned with corresponding cyclic shift parameters. A peak appearing in the upper graph of FIG. 11 indicates a primitive index having the largest CM in the subgroup.

  Regardless of cell size through complex alignment with cyclic shift parameters and CM characteristics, each cell can use a contiguous logical index, and the CM-based cell design can be determined according to the characteristics of each cell. Yes, within each cell, the base station can use the smallest logical index assigned to it for terminals in a specific power limited environment. For example, the base station can use the smallest logical index as a dedicated preamble to the terminal that hands over. In the smallest cell size interval, the size of a cell that can be supported is considerably small, and there can be an index having a value of 0 km or less, and such an index is an index that cannot be used by the constrained cyclic shift. Show. Further, the section can be subdivided for easier index assignment. In FIG. 11, the first section is divided into 0 to 1.1 km, but the section can be further divided to perform separate CM base alignment. For example, the first section can be divided into two sections of 0 to 500 m and 500 m to 1.1 km, and CM base alignment can be performed.

  Table 5 shows a physical index associated with the Ncs configuration section.

Table 5 shows that a plurality of physical primitive indexes are divided into a plurality of subgroups according to a predetermined cyclic shift parameter (Ncs), and continuous logical indexes are assigned within the subgroups.

  As described above, in a cell having a high-speed moving body by setting a logical index, a sequence suitable for the cell size can be easily selected. In addition, when the cell requires low CM characteristics, an index having low CM characteristics is used by simply selecting the previous index among indexes that can be used in the size of the cell. Can do. Table 5 does not mean that only index (physical index or logical index) values associated with Ncs can be used. In a cell having a medium / low speed moving body (low / middle mobility cell), an appropriate index can be selected and used for the CM characteristic of the cell regardless of the cell size. It is also possible to set a separate Ncs section table that can be used in a cell having a medium / low speed moving body. At this time, it is possible to select a table to be applied using a division signal of a cell having a medium-low speed moving body and a cell having a high-speed moving body.

  FIG. 12 illustrates CM characteristics and maximum support cell radius characteristics associated with a logical index according to another embodiment of the present invention. Figure 5 shows an alignment based on multiple properties and pair allocation.

  Referring to FIG. 12, the ZC sequence has a complex conjugate symmetry property, and an index having the complex conjugate symmetry can be sequentially paired. .

  Equation 5 below shows the complex conjugate symmetry of the ZC sequence.

Here, (.) ^{* Indicates} a complex conjugate. Such a characteristic cannot be obtained when only one index is used in a cell, but the complexity of the detector is reduced by half when multiple indexes having complex conjugate symmetry characteristics are used in each cell. Can be made. Indexes having complex conjugate symmetry may be sequentially arranged while applying CM-based alignment, maximum support cell radius-based alignment, composite alignment, and the like. When the indexes are paired, the base station signals only one logical index value, and the UE naturally uses the pair index when increasing the logical index as necessary. To use.

  In Table 5, each group includes an odd number of indexes, and one index of the upper group can be used in the lower group in order to configure complex conjugate symmetry characteristics. This can be expressed as in Table 6.

As described above, the result of configuring the complex conjugate symmetry is similar to the result of the composite alignment in FIG. That is, the indexes can be aligned so that pair allocation is possible without deteriorating specific characteristics.

  FIG. 13 illustrates CM characteristics and maximum support cell radius characteristics associated with a logical index according to another embodiment of the present invention. Another embodiment shows an alignment based on multiple properties and pair allocation.

  Referring to FIG. 13, the section divided in FIG. 12 can be further subdivided. For example, the maximum cell radius can be further increased by dividing the sections of the configuration numbers 11 and 12 in Table 4 into smaller portions by half. Table 7 is a mapping table showing a physical index for each section when the 11th and 12th sections are divided in half.

Table 7 can be applied to increase the maximum cell radius from 29.14 km to 34.15 km. Here, an example is given in which the specific section is divided into half and rearranged, but this is merely an example. The size of dividing a specific section can be divided into various methods. For example, in order to be able to support a specific maximum cell radius, a section can be divided on the basis of the specific maximum cell radius. Alternatively, the sections can be divided so as to be double the number of indexes used in the specific section. It is also possible to group a group with a small number of indexes into one group and apply a second sort. Alternatively, the second alignment can be applied by dividing a group having a plurality of indexes into two (or two or more) groups.

  FIG. 14 shows a CM characteristic and a maximum support cell radius characteristic with a logical index according to another embodiment of the present invention. This is a case where the index is divided into groups with reference to a specific CM, and is aligned with the maximum support cell size within each group.

  Referring to FIG. 14, first, the indexes are arranged according to the CM characteristics, and then the SC-OFDMA QPSK CM is divided into a group having a CM higher than 1.2 dB and a group having a lower CM, and the maximum supported cell radius in each group. (Max. Supportable cell radius). Groups with CMs lower than QPSK can be arranged in order of decreasing maximum support cell size, and groups with CMs higher than QPSK can be arranged in order of increase of maximum support cell size. Table 8 shows the mapping of the physical index for each section when the indexes are arranged according to the CM characteristics, the groups are divided based on one CM value of 1.2 dB, and then the maximum support cell size is arranged in each group. It is a table.

<Comparison with reuse factor in large cell>
FIG. 15 illustrates the number of restricted cyclic shifts available per logical index with Ncs for CM mapping according to one embodiment of the present invention. FIG. 16 illustrates the number of limited cyclic shifts available per logical index with Ncs for maximum supported cell size mapping according to one embodiment of the present invention. FIG. 17 illustrates the number of limited cyclic shifts available per logical index with Ncs for hybrid mapping according to one embodiment of the present invention.

  Referring to FIGS. 15 to 17, the maximum support cell size mapping and the composite mapping may use an index that is continuous in a high speed cell, as compared with the CM mapping. For example, in 20 cells, Ncs = 13 for the first cell, Ncs = 26 for the next two cells (second cell, third cell), Ncs = 38 for the next three cells, Assume that the next four cells have Ncs = 38, the next four cells have Ncs = 52, and the next four cells have Ncs = 64. At this time, a pair index allocation method is applied to each mapping. Ncs means the number of cyclic shifts associated with the cell size. In FIG. 15, the number of cyclic shifts available at any logical index appears as zero. On the other hand, in FIGS. 16 and 17, it can be seen that the available cyclic shifts appear continuously from the start of the logical index associated with each Ncs. That is, a continuous index cannot be used in CM mapping, but a continuous index can be used in maximum support cell size mapping and composite mapping.

  FIG. 18 shows an example of a logical index assigned to a cell for CM mapping according to an embodiment of the present invention. FIG. 19 illustrates an example of a logical index assigned to a cell for maximum support cell size mapping according to an embodiment of the present invention. FIG. 20 illustrates an example of a logical index assigned to a cell for maximum support cell size mapping according to one embodiment of the present invention. FIG. 18 shows what indices are assigned to cells based on the assumptions in FIGS.

  Referring to FIG. 18 to FIG. 20, it is assumed that all cells are high mobility cells. In FIG. 18, it can be seen that a continuous index cannot be used in a large cell. In contrast, in FIGS. 19 and 20, it can be seen that even a large cell can use all consecutive indexes. In FIG. 19 and FIG. 20, when there is one cell with Ncs = 209, a configuration of four cells with Ncs = 167 is possible. However, in FIG. 18, only a cell configuration with three Ncs = 167 is possible. This is because it is impossible to use consecutive indexes in FIG. More importantly, in FIG. 18, when there is one cell with Ncs = 209 and three cells with Ncs = 167, cells with Ncs = 139, Ncs = 104, Ncs = 83, and Ncs = 76. It can be seen that no one can be constructed. On the other hand, in FIGS. 19 and 20, it can be seen that cells of various sizes can be constructed. In addition, it can be seen that a cell having a high-speed moving body in FIG. Of course, all such indexes can be used when mixed with cells having only slow mobiles, but greatly reduce the ability to construct cells with fast mobiles. When the continuous index cannot be used in this way, it can be seen that the reuse factor is greatly reduced when there are a plurality of large cells. By using consecutive indexes, extra space can be used by other cells. In other words, the use of consecutive indexes may not make a big difference in a network configured only with small cells, but support for using consecutive indexes in a network with multiple large cells is a reuse factor. Can be increased. 18 to 20 consider the case where all the cells have a high-speed moving body. However, when there are cells having a low-speed or medium-speed moving body at the same time, consecutive indexes are used for the same reason. The reuse factor is constrained when it cannot. In addition, when using a continuous index in a cell having a low-speed or medium-speed moving body, the reuse factor of the cell having a high-speed moving body is further restricted.

  The exact index of each mapping used here is as shown in Tables 9-11. Table 9 is an index used for CM mapping, Table 10 is an index used for maximum support cell size mapping, and Table 11 is an index used for composite mapping. In Tables 9 and 10, physical indexes for logical indexes 1 to 838 are listed in order.

<Support cell size alignment and CM classification>
FIG. 21 illustrates a method for searching a logical index according to CM characteristics according to an embodiment of the present invention. FIG. 22 illustrates a method for searching a logical index according to CM characteristics according to another embodiment of the present invention. FIG. 23 illustrates a method for searching a logical index according to CM characteristics according to another embodiment of the present invention.

  Referring to FIGS. 21 to 23, the physical index is first sorted according to the support cell size. Thereafter, the usable index in each cell is changed in usage according to the characteristics of one transmitted index. The logical index assignment can be formed according to one logical index + Ncs. This can be accomplished in two ways:

  In the first method, each cell uses one sequence class (see FIG. 20). It is divided into a low CM index and a high CM index.

  If the transmitted logical index is lower than the SC-FDMA QPSK CM (1.2 dB) or has the same CM characteristics, the nearest adjacent logical index lower than the SC-FDMA QPSK CM or the same CM characteristics is Find and use in order. If the transmitted logical index has a higher CM characteristic than the SC-FDMA QPSK CM, the nearest neighboring logical index having a higher CM characteristic than the SC-FDMA QPSK CM is searched and used in order. When only one sequence type is used, it is possible to use a logical index that is unconditionally adjacent without a specific criterion such as QPSK CM.

  Alternatively, one cell can use both sequence types (low CM or high CM) (see FIGS. 20 and 21). It is divided into a low CM index, a high CM index, and a mixed CM index.

  If the transmitted logical index is lower than the SC-FDMA QPSK CM (1.2 dB) or has the same CM characteristics, the nearest adjacent logical index lower than the SC-FDMA QPSK CM or the same CM characteristics is Search and use in order. At this time, when the end of the Ncs segment is reached, the index is reset as the index having the first higher CM of the Ncs segment. If the transmitted logical index has higher CM characteristics than SC-FDMA QPSK CM (1.2 dB), the nearest adjacent logical index having higher CM characteristics than SC-FDMA QPSK CM is searched and used in order. . At this time, when the end of the Ncs segment is reached, the index is reset as the index with the first lower CM of the next Ncs segment.

  The direction of searching for an index having the same characteristic (+/−, the direction in which the index increases / decreases) may be the same or different. The direction in which the index is searched does not affect the proposed technique as in the above-described index alignment direction (ascent / descent).

  FIG. 24 illustrates a CM characteristic associated with a physical physical index according to an embodiment of the present invention.

Referring to FIG. 24, a sequence class can be defined according to a physical index of a sequence. The primitive physical index can be classified by setting a CM type critical value. The classification of the primordial physical index can be easily performed by checking whether the selected physical index belongs to a high CM area or a low CM area. For example, when a 1.2dB a CM classification threshold value, a high CM region may be sure that is easily determined as _[238, N ZC -238]. When such a method is used, a complicated table is not required for index alignment (or index mapping), and a simple expression can be generated.

  The mapping to the physical index u_phy (u_log) in response to the logical index u_log based on the maximum support cell size (or Ncs) is as follows.

Here, α _{i, 1} = (N _ZC +1), α _{i, 2} = 2i−1, α _{i, 3} = 2i, u ′ (r) = (− 1 / r) mod N _ZC .

  Equation 7 shows an example of selection of adjacent usable indexes when multiple indexes are used in a cell.

Here, u _log ++ means the next logical index associated with u _log and I _t = 238 (eg, u _log +1, u _log +2, u _log +3,...). This is a case where all indexes are searched in the + direction (direction in which the index increases). If a mixed CM index is not allowed, the search process is simple. When the low CM sequence reaches the _NZC- 1 boundary via the u _log ++ process, it is reset at the first logical index of u _log ++. However, a condition is necessary if a mixed CM index is allowed. When u _log ++ reaches the N _cs sequence boundary, it is reset at the first logical index in the u _log ++ Ncs segment. For higher CMs, when the Ncs segment boundary is reached in the u _log ++ process, u _log ++ is reset with the first logical index of the next Ncs segment. At this time, when the mixed CM index is not allowed, the CM characteristic when reset is reset with the first index having the same characteristic as the transmitted index characteristic. When the mixed CM index is allowed, the CM characteristic of the transmitted index is reset. It can be reset with a higher CM or lower CM index predetermined according to the characteristics.

  Equation 8 shows another example of selecting adjacent usable indexes when multiple indexes are used in a cell.

Here, u _log ++ means the next logical index associated with u _log and I _t = 238 (eg, u _log +1, u _log +2, u _log +3,...). This is a case where the index is searched in the + direction and the − direction (direction in which the index increases and decreases).

  If it is difficult to express the index alignment in a formula, each base station and terminal must have a large alignment table of 838 * 10 bits (1-838) = 8380 bits. However, given Equation 6, the base station and the terminal can use max. Supported cell size ordering without an alignment table. Table 12 represents the physical index to logical index mapping based on the maximum supported cell size using Equation 6.

In all the embodiments described above, when ordering an index with a particular property, the order of values having the same property has no effect on the order of the alignment. Also, the order of pair indexes does not affect the order of alignment. Further, in all of the alignment (mapping) methods of the embodiments, an example is given in which the order is determined in the direction in which the CM or the maximum support cell size increases as the index increases, but this is only an example. The order may be determined in the direction in which the CM or the maximum support cell size increases in each group as the index increases, and the order may be determined in the direction in which the size decreases. Further, the order (^) may be determined for the peak shape, and the order (v) may be determined for the valley shape. In addition, the directionality of the CM or maximum support cell size may be set differently for each group.

  FIG. 25 illustrates CM characteristics and maximum support cell radius characteristics associated with a logical index according to another embodiment of the present invention. As the logical index increases, the maximum support cell size is aligned in an increasing direction, and the CM is aligned in a decreasing direction. FIG. 26 shows CM characteristics and maximum support cell radius characteristics associated with a logical index according to another embodiment of the present invention. Each CM group is grouped by cyclic shift unit (Ncs). As the logical index increases, the maximum support cell radius size aligns in the increasing direction, the odd group of CMs aligns in the decreasing direction, and the even group of CMs aligns in the increasing direction. .

  Referring to FIG. 25 and FIG. 26, the directionality of CM or maximum support cell size can be determined differently for each group. When the maximum support cell size is arranged in the increasing order and then the CM is arranged in the decreasing order, it is shown in FIG. Or, the odd-numbered groups are arranged in the order in which the CM decreases, and the even-numbered groups are arranged in the order in which the CM increases, as shown in FIG. Thus, by changing the order of alignment in adjacent groups, more adjacent indexes having a low CM can be used in cells having a low-speed moving body irrespective of the maximum support cell radius.

  In all the embodiments described above, when one index is assigned to each cell in the alignment (mapping) method, each terminal transmits an index transmitted as necessary to satisfy the number of random access preambles required per cell. It is possible to use an index while incrementing or decrementing the index by one. When using an index while adding +1, after using up to the maximum index 838, it is possible to return to the smallest index 1 and use it. When the index is used while −1 is set, after using up to the minimum index 1, it is possible to return to the largest index 838 and use it. Also, the index increasing direction (+/−) can be used differently according to each characteristic (for example, lower CM / higher CM). When the maximum support cell size increases in accordance with the increase in the index, the usable index is limited in the large cell, so it is desirable to allocate the index from the large cell. At this time, assigning the largest index from the largest cell and using the index while -1 is a method that can simplify the cell design.

<Example of composite alignment>
FIG. 27 shows a process of grouping CM alignments into two groups. FIG. 28 shows a process of grouping the alignments with the maximum support Ncs characteristic in each group into Ncs groups. FIG. 29 illustrates a process of aligning according to CM characteristics within each Ncs group.

  Referring to FIGS. 27 to 29, (1) an index is aligned with a CM characteristic. The QPSK CM of SC-FDMA is divided into groups higher and lower than 1.2 dB. As shown in FIG.

  (2) After aligning the whole index according to the maximum support cell radius, the section is divided by the Ncs value (or the maximum support cell radius value). After aligning each group according to the maximum support cell radius, the sections are divided into maximum support cell radius values for Ncs. At this time, it is possible to further subdivide the method of dividing all the specific Ncs values according to the Ncs value or the method of grouping and dividing the plurality of specific Ncs values or the specific Ncs values. Here, it is a case where a group corresponding to all Ncs values is used, and the divided sections are shown in FIG.

  (3) Align according to CM characteristics within each divided section. As shown in FIG. Here, 13, 15, 18, 22, 26, 32, 38, 46, 59, 76, 119, 167, 237, 279, 419 were used as the Ncs sample values. Table 13 shows the relationship between the physical index and the logical index according to the result of FIG.

In Table 13, there are a plurality of groups having only a small number of indexes. Groups having only a small number of indexes can be combined into one group together with adjacent groups.

  In all the embodiments described above, when performing pair allocation, the relative positions of adjacent two-pair indexes do not affect the proposed technique. Also, when ordering according to a particular characteristic (eg, CM, maximum support cell size (or Ncs, etc.)), the order of indices with similar characteristics does not affect the proposed technique.

  When using the above-described method, the terminal and the base station must have a mapping table indicating the relationship between the physical index and the logical index in the memory. At this time, a total of 838 indexes may be stored in the memory, or only half of them may be stored by pair assignment. When only half is stored, it can be processed assuming that there is a (N-i) th index after one index (i).

  After the indexes are aligned using the above-described method, when the base station is notified of indexes usable in the cell, a method of notifying the number of Ncs components and one logical index can be used. At this time, it is possible to use a method in which one logical index is notified by a logical index from 1 to 838 using 10 bits. As another method, an index from 1 to 419 can be informed using 9 bits using only one value of the pair assignment. At this time, for the separated use of the pair index, an additional 1 bit indicating whether the pair index is the leading index of 1 to 419 or the following index of 420-838 is used. Can do. When the index is notified by only 9 bits, the processing can be performed assuming that there is the Ni-th index after one index (i).

  FIG. 30 is a flowchart illustrating a random access process according to an embodiment of the present invention.

  Referring to FIG. 30, a terminal (UE) receives random access information from a base station (BS) (S310). The random access information includes information related to generation of a cyclic shift unit (Ncs) for selecting a random access preamble and a random access preamble. The cyclic shift unit (Ncs) is a unit in which the ZC sequence is cyclically shifted, and the information related to generation of the random access preamble is information related to one logical index. The logical index is an index to which the physical primitive index of the ZC sequence is mapped. The logical index is mapped to a physical source index that is ordered by a specific metric (eg, CM). Also, the logical index can be aligned in a complex alignment scheme. For example, it is mapped to a physical primitive index that is aligned according to the cyclic shift parameter (Ncs) and CM.

  Information regarding the cyclic shift parameter (Ncs) and the random access preamble may be transmitted via a part of system information (part) or a downlink control channel. There is no limitation on the method and form for transmitting information on the cyclic shift parameter (Ncs) and the random access preamble, and the technical idea of the present invention is not limited thereto.

  The terminal obtains a physical primitive index mapped from the logical index (S320). Each cell has 64 usable preambles. A set of 64 preamble sequences in a cell can be obtained by ascending cyclic shifts from the available cyclic shifts of the original ZC sequence with logical index. If 64 random access preambles cannot be generated from one original ZC sequence, additional preamble sequences can be obtained from the original sequence having a logical index that continues until 64 sequences are obtained. it can. A logical primitive index is circular. For example, when Nzc = 838, logical index 9 is continuous to 837. Therefore, the terminal can obtain all available random access preambles from one logical index.

  Even if the base station informs only one logical index, the terminal can look for possible 64 random access preambles. Also, since consecutive logical indexes are aligned so that the corresponding physical primitive ZC sequences have similar characteristics, all generated sequences have almost similar characteristics. A primitive ZC sequence corresponding to a continuous logical index has a complex conjugate symmetry. This means that the sum of two primitive indexes corresponding to two consecutive logical indexes is the same as the length of the primitive ZC sequence.

  The logical index is obtained by arranging the physical primitive index of the ZC sequence according to CM after sub-grouping and then sequentially mapping them. The subgroup groups ZC sequences into cyclic shift units (Ncs). Even if an adjacent logical index is selected, a ZC sequence having characteristics similar to those of an existing logical index can be obtained. Therefore, even with only one logical index, the terminal can acquire 64 preamble sequences necessary for selecting a random access preamble.

  As described above, the logical index is obtained by classifying the ZC sequences into subgroups according to the cyclic shift parameter (Ncs), and mapping the physical indexes in a state where the ZC sequences are arranged by CM in the subgroups. is there. Therefore, logical sequences belonging to one subgroup have the same cyclic shift parameter (Ncs). Even if the base station assigns only a logical sequence considering the mobility of the terminal, the terminal may obtain multiple ZC sequences with similar CM characteristics with the same cyclic shift parameter (Ncs). It can be done.

  The terminal transmits the selected random access preamble to the base station via RACH (Random Access Channel) (S330). The terminal arbitrarily selects one of 64 usable random access preambles and transmits the selected random access preamble.

  The base station transmits a random access response, which is a response to the random access preamble (S340). The random access response may be a MAC message composed of a MAC that is an upper layer of the physical layer. The random access response is transmitted via a DL-SCH (Downlink Shared Channel). The random access response is indicated by an RA-RNTI (Random Access-Radio Network Temporary Identifier) transmitted via a PDCCH (physical downlink control channel). The random access response may include at least one of timing alignment information, initial uplink grant, and temporary C-RNTI (Temporary Cell-Radio Network Temporary Identifier). The timing alignment information is timing correction information for uplink transmission. The initial uplink grant is information on resources for a terminal that has attempted connection to perform a scheduled transmission through the uplink for the first time. Temporary C-RNTI refers to a C-RNTI that is not permanent until the time the collision is resolved.

  The UE performs uplink transmission scheduled via the UL-SCH (S350). If there is additional data to be transmitted if necessary, the terminal performs uplink transmission to the base station and performs a collision resolution process.

  If an error occurs during transmission of the random access preamble, the random access process is delayed. Since the random access process is a procedure performed in the initial connection to the base station or the handover process, the delay in the random access process may cause a problem of connection delay or service delay. When the cyclic shift parameter (Ncs) considering the high-speed environment of the terminal is used, since the terminal can obtain 64 preamble sequences suitable for the high-speed environment, the random access preamble is reliable in the high-speed environment. Can be transmitted.

  Using continuous logical indexes, a random access preamble set with similar physical characteristics can be generated. Control signaling for generating the random access preamble can be minimized. Random access failures can be reduced in a high-speed environment, and efficient cell planning can be performed.

  FIG. 31 is a block diagram showing elements of a terminal to which the embodiment of the present invention is applied. The terminal (50) includes a processor (processor, 51), a memory (memory, 52), an RF unit (RF unit, 53), a display unit (display unit, 54), and a user interface unit (user interface unit, 55). . The processor 51 is responsible for sequence generation and mapping, and functions related to various embodiments described above can be implemented. The memory (52) is connected to the processor (51) and stores a terminal driving system, applications, and general files. The display unit 54 can display various information of the terminal and use well-known elements such as an LCD (Liquid Crystal Display) and an OLED (Organic Light Emitting Diodes). The user interface unit (55) may be a combination of well-known user interfaces such as a keyboard and a touch screen. The RF unit (53) is connected to the processor to transmit and / or receive a radio signal.

  All the functions described above are performed by a processor such as a microprocessor, controller, microcontroller, ASIC (Application Specific Integrated Circuit) associated with software or program code coded to perform the functions. be able to. The design, development and implementation of the code will be obvious to those skilled in the art based on the description of the present invention.

The present invention also provides, for example:
(Item 1)
In a method for generating a logical index of a primitive ZC (Zadoff-Chu) sequence,
A logical index of a plurality of primitive ZC (Zadoff-Chu) sequences is divided into one or more subgroups according to a predetermined cyclic shift parameter, and the subgroup includes at least one primitive ZC (Zadoff-Chu). ) Including a logical index of a sequence, and mapping a primitive index of a Zadoff-Chu sequence in the subgroup to a continuous logical index.
(Item 2)
The method according to item 1, wherein the primitive ZC sequence has a zero correlation zone with a length of the cyclic shift parameter-1 of the primitive ZC sequence.
(Item 3)
2. The method of item 1, further comprising aligning a source index of a source ZC sequence within a subgroup according to specific criteria prior to mapping to the logical index.
(Item 4)
Item 4. The method according to Item 3, wherein the specific criterion is CM (Cubic Metric).
(Item 5)
The method further includes performing a cyclic shift of the original ZC sequence as the cyclic shift value, wherein the cyclic shift value is obtained using a cyclic shift parameter of the ZC sequence and a Doppler shift of the detection stage. the method of.
(Item 6)
6. The method of item 5, wherein the cyclic shift parameter of the original ZC sequence is smaller or the same as a pre-designated cyclic shift parameter of a subgroup of the original ZC sequence.
(Item 7)
6. The method according to item 5, wherein the cyclic shift value of the primitive ZC sequence is larger than the cyclic shift parameter of the primitive ZC sequence.
(Item 8)
The kth element c (k) of the primitive ZC sequence is as follows:
Where N is the length of the ZC sequence and M is a physical primitive index that is a relative prime number with N.
(Item 9)
The method of claim 1, further comprising aligning the subgroups with pre-specified cyclic shift parameters.
(Item 10)
Item 2. The method of item 1, wherein the last logical index of the first subgroup is contiguous to the first logical index of the second subgroup, and the first subgroup and the second subgroup are contiguous. .
(Item 11)
In a method for performing a random access process in a wireless communication system,
Selecting a random access preamble from a plurality of random access preambles, wherein the plurality of random access preambles are generated from available cyclic shifts of a source ZC sequence having a continuous logical index, wherein the continuous logical index is: Mapped to the primitive index of the primitive ZC sequence;
Transmitting the selected random access preamble and receiving a random access response including an identifier of the selected random access preamble.
(Item 12)
Item 12. The method of item 11, wherein the sum of the two primitive indices of the primitive ZC sequence corresponding to the two consecutive logical indexes is the same as the length of the primitive ZC sequence.
(Item 13)
12. The method according to item 11, wherein the random access response on a DL-SCH (downlink shared channel) is indicated by a random access identifier on a PDCCH (physical downlink control channel).
(Item 14)
12. The method of item 11, further comprising receiving a logical index and a cyclic shift parameter for generating the plurality of random access preambles from a base station, wherein the cyclic shift parameter is used to obtain a cyclic shift value. .
(Item 15)
In a method for performing a random access process in a wireless communication system,
Transmitting a pre-specified cyclic shift parameter and a source logical index for generating a plurality of random access preambles;
Receiving a random access preamble selected from the plurality of random access preambles, the plurality of random access preambles having a source logical index and at least one continuous logical index in the source logical index; Generated from the available cyclic shifts of the sequence,
Transmitting a random access response including an identifier of the random access preamble.
(Item 16)
16. The method of item 15, wherein the source logical index is broadcast as part of system information.
(Item 17)
16. A method according to item 15, wherein the sum of two primitive indices of a primitive ZC sequence corresponding to two consecutive logical indexes is the same as the length of the primitive ZC sequence.
(Item 18)
16. The method of item 15, further comprising receiving a cyclic shift parameter, wherein the cyclic shift value is obtained using the cyclic shift parameter.
(Item 19)
In a method for generating a random access preamble,
Generating a plurality of random access preambles from a first primitive ZC sequence having a first primitive index mapped to a first logical index in increasing order of a cyclic shift, and a predetermined number of said first primitive ZC sequences Generating a plurality of additional random access preambles in increasing cyclic shift order from a second primitive ZC sequence having a second primitive index that is mapped to a second logical index when no random access preamble is generated, The second logical index is a continuous method to the first logical index.
(Item 20)
20. The method of item 19, further comprising receiving the first logical index from a base station.
(Item 21)
20. A method according to item 19, wherein the predetermined number of random access preambles is 64.
(Item 22)
20. The method of item 19, further comprising receiving information regarding a cyclic shift parameter, wherein the cyclic shift value is obtained using the cyclic shift parameter.
(Item 23)
20. The method of item 19, further comprising selecting a random access preamble from the plurality of random access preambles and the plurality of additional random access preambles and transmitting the selected random access preamble.
(Item 24)
In a method for generating a random access preamble,
Until the information about the source logical index is received and a predetermined number of random access preambles are obtained, a cyclic shift from a source ZC sequence having a continuous logical index starting from the source logical index. A method in which a plurality of random access preambles are generated in increasing order, and the continuous logical index is mapped to a primitive index of the primitive ZC sequence.
(Item 25)
25. The method of item 24, wherein the plurality of random access preambles are generated in an increasing order of cyclic shifts from a primitive ZC sequence.
(Item 26)
26. The method of item 25, further comprising receiving information regarding a cyclic shift parameter, wherein the cyclic shift value is obtained using the cyclic shift parameter.
As described above, the present invention has been described with reference to the embodiments. However, a person having ordinary knowledge in the technical field can make various modifications of the present invention within the scope of the technical idea and area of the present invention. It can be understood that modifications and changes can be made. Accordingly, the invention is not limited to the embodiments described above, but includes all embodiments within the scope of the claims.

10, 50 Terminal 20 Base station 51 Processor 52 Memory 53 RF unit 54 Display unit 55 User interface unit

Claims (4)

A user equipment (UE) that performs a random access process using a logical index of a primitive ZC (Zadoff-Chu) sequence,
The user equipment is
A processor configured to receive a first logical index, wherein the first logical index is one of successive logical indexes mapped to a physical source index of a source ZC sequence. The physical primitive index is divided into subgroups according to a cyclic shift parameter, each subgroup including at least one physical primitive index; and
A communication unit configured to receive information on a cyclic shift parameter and to transmit a random access preamble based on one preamble sequence of a predetermined number of available preamble sequences; Prepared,
The predetermined number of available preamble sequences includes preamble sequences in order of increasing cyclic shift from a first source ZC sequence having a first physical source index mapped to the first logical index, And cycling from a second source ZC sequence having a second physical source index that is mapped to a second logical index if the predetermined number of available preamble sequences cannot be found from the first source ZC sequence. Sought by further including a preamble sequence in order of increasing shift, the second logical index is continuous with respect to the first logical index;
The sum of the first physical source index and the second physical source index is equal to the length of the source ZC sequence, the value of the cyclic shift is obtained from the cyclic shift parameter, and the value of the cyclic shift Is determined based on whether a limited cyclic shift associated with high mobility is used, and a distinction signal is further received from the base station indicating whether the limited cyclic shift is used machine. The user equipment according to claim 1, wherein the predetermined number of preamble sequences available for random access is 64.   The user equipment of claim 1, wherein the first logical index is broadcast. The kth element c (k) of the primitive ZC sequence is
The user equipment of claim 1, wherein N is a length of the primitive ZC sequence, M is a physical primitive index, and is a relative prime number with N.