WO2009154410A2

WO2009154410A2 - Method for transmitting physical layer id information

Info

Publication number: WO2009154410A2
Application number: PCT/KR2009/003270
Authority: WO
Inventors: 한승희; 권영현; 드라간 뷔쉬; 김동철; 문성호; 곽진삼; 노민석; 이현우
Original assignee: 엘지전자 주식회사
Priority date: 2008-06-18
Filing date: 2009-06-18
Publication date: 2009-12-23
Also published as: WO2009154410A3

Abstract

Disclosed is a method for transmitting a cell ID of a specific type as physical layer ID information in addition to existing cell ID information. To this end, a method for increasing the number of cell IDs used in transmission of existing cell ID information in a synchronization channel can be employed, and a part of existing cell IDs can be set to be used for the transmission of additional specific type cell ID information. More specifically, in a case of increasing the number of cell IDs, a method for increasing the number of cell ID groups associated with a sub-synchronization channel without ambiguity problems and collision problems, a method for adding the number of cell IDs associated with a main synchronization channel in such a manner so as to satisfy characteristics of complex symmetry, a method for transmitting information using a transmission timing relationship of a main synchronization code and a sub synchronization code, and a method for transforming a scrambling scheme can be used. Further, in a case of reserving a part of existing cell IDs, characteristics of complex symmetry are considered in relation to a main synchronization channel, and ambiguity and collision problems are considered in relation to a sub-synchronization channel.

Description

[Name of invention]

Physical Layer I D Information Delivery Method

Technical Field

The following description relates to a method of transmitting cell identification information in a wireless communication system, and specifically, to a method of efficiently delivering additional cell identification information with minimal impact on an existing system.

Background Art

The cell identification information (or cell identifier (ID)) refers to an identifier for identifying a cell having a specific location area in a wireless network. The particular location area here coordinates radio related tasks within the coverage area and includes at least one base station (BTS or Node B) that provides a connection over the air interface between the network and the mobile station (or UE). The base station (BTS, Node B or eNode B) described above is an access point for indoor or outdoor coverage.

On the other hand, an access point for home coverage is a femtocell, a Node B, an evolved Home NodeB (eHNB), or a Closed Subscriber, which is a small cell base station generally used in a residential or small business environment. Group). In the following description, such a small base station is referred to collectively as a "CSG" or "CSG cell" for convenience of description. It is not necessary to limit the meaning of the term.

The CSG is connected to the operator's network by means of broadband connections such as DSL or cable. Such CSG is not allowed to allow cell operators to access or be restricted. To extend indoor service coverage.

The most problem in the current standardization step for such a CSG is to define a cell ID for the UE to distinguish whether the cell is a CSG or a CSG cell at an early stage of cell identification. This is because a particular UE may be allowed to connect to that CSG while another UE may not be allowed to connect to that CSG.

In more detail, if only the upper layer identification information is used to distinguish the CSG cell, the UE may receive a signal through the lower layer and may read the upper layer ID information only after completing the initial cell discovery. If the read upper layer ID is a CSG cell to which the UE is not allowed to access, the UE has unnecessary power consumption and time delay.

Therefore, there is a need for a technique for reducing power consumption of a UE and minimizing additional delay overhead in a handover process for a UE to which an unauthorized CSG cell connects.

[Detailed Description of the Invention]

[Technical problem]

In order to solve the problems as described above, the present invention is to propose a method for the UE to easily perform the discovery and identification of the CSG cell in the initial stage of cell discovery.

In addition, the present invention provides a more general method of transmitting additional physical layer identification information to the existing cell ID information as well as searching for the CSG cell.

Technical Solution

In one aspect of the present invention to solve the problems as described above the existing sal A method of transmitting additional physical layer cell ID information by increasing the number of IDs is provided. In one embodiment, there is provided a method of transmitting physical layer cell ID information, the primary synchronization signal (PSS) and the secondary synchronization signal (SSS).

And transmitting each of a synchronization signal, the physical layer cell according to a temporal relationship between the transmission of the primary synchronization signal and the transmission of the secondary synchronization signal.

We propose a method of representing ID-related information.

In this case, the physical layer cell ID related information may indicate the cell ID information of the serving cell and the service attribute of the serving cell. Herein, the service attribute is determined by the serving cell.

It may indicate one or more of whether it is a closed subscriber group (CSG) cell, a relay station cell, a multimedia broadcast multicast service (MBMS) indicator, or a hot spot indicator. In addition, the cell ID information of the serving cell may be all or part of the serving cell ID information.

In a specific embodiment, a CSGC Closed Subscriber Group (CSGC) cell ID is displayed when the sub-synchronous signal is transmitted after the main synchronization signal is transmitted, and a cell other than the CSG cell is transmitted when the main synchronization signal is transmitted after the sub-synchronous signal is transmitted. It may be set to indicate an ID.

On the other hand, in another embodiment, two sub-synchronization channels (Secondary) according to the combination of the first segment and the second segment, respectively, in the method for transmitting physical layer cell ID information

Synchronization Channel; Performing scrambling according to any one of first type scrambling or second type scrambling to the S-SCH) signal; And transmitting the scrambled two signals as two sub-synchronization codes (SSCs), wherein the first type scrambling and the second type scrambling are performed by the first type scrambling. In one or more of the form of scrambling based on which of the segment and the second segment is performed, a combination of main sync code based scrambling sequences multiplied by each sub-sync code, and a scrambling sequence multiplied by each sub sync code. The scrambling scheme is classified by the scrambling method, and a method of indicating physical layer cell ID related information is provided according to which of the first type scrambling and the second type scrambling is applied in the scrambling step.

Also in the present embodiment, the physical layer cell ID related information includes whether the serving cell is a closed subscriber group (CSG) cell, a relay station cell, a multimedia broadcast multicast service (MBMS) indicator, a hot spot. Can represent one or more of the indicators.

Further, in a specific embodiment, when the second type scrambling is applied in the scrambling step, the two sub-synchronization codes transmitted indicate a CSG cell ID, and when the first type scrambling is applied in the scrambling step, the transmission The two sub-synchronization codes may be set to indicate cell IDs other than the CSG cell.

In this case, the first type scrambling is performed by applying scrambling to a second segment using a scrambling sequence based on the first segment, and the second type scrambling uses a scrambling sequence based on the second segment. By performing scrambling on the first segment.

The main sync code based scrambling sequence includes a first main sync code based scrambling sequence and a second main sync code based scrambling sequence, wherein the first type scrambling is one of the two sub sync channel signals. Part 1. Sync Channel The first type of scrambling is performed as scrambling using the first main sync code based scrambling sequence to the signal and the second main sync code based scrambling sequence to the second secondary sync channel signal. The second main sync code based scrambling sequence may be set to a signal, and the second sub sync channel signal may be set as scrambling using the first main sync code based scrambling sequence.

Further, the second type scrambling may be set differently from the first type scrambling in at least one of a main synchronous code based scrambling sequence used, the first segment based scrambling sequence and the second segment based scrambling sequence. It may be.

Meanwhile, in another embodiment of the present invention, in the physical layer cell ID information transmission method, performing phase modulation according to any one of different types of phase modulation preset to two sub-synchronization codes (SSCs). ; And transmitting the phase modulated two sub-synchronization codes, wherein the preset different types of phase modulation are divided according to different lengths of two code values multiplied by the two sub-synchronization codes. In the phase modulation step, there is provided a method of transmitting cell ID information indicating physical layer cell ID-related information according to whether different preset types of phase modulation schemes are applied.

In this case, the preset different types of phase modulation include a first type phase modulation and a second type phase modulation, and the first type phase modulation and the second type phase modulation constitute the two sub-sync codes. The first code and the second code have different combinations of phase modulation of any one of BPSK, QPSR or M-PSK. The CSG cell may be configured to represent a CSG cell when the first type phase modulation is applied and to indicate a cell other than the CSG cell when the second type phase modulation is applied.

The preset different types of phase modulation may include first type phase modulation, second type phase modulation, and third type phase information, and the first type phase modulation to the third type phase modulation may include the two types of phase modulation. The first code and the second code constituting the auxiliary sync code are performed by applying different combinations in any one of the phase modulation of the BPSK method, the QPSK method, or the M-PSK method, and the first type phase modulation is applied. In this case, the CSG cell may be represented, and when the second type phase modulation is applied, the repeater cell may be represented. When the third type phase modulation is applied, the CSG cell may be set to indicate a cell other than the CSG cell or the repeater cell.

In another embodiment of the present invention, the method may further include: selecting a sequence having a root index of any one of the first to fourth tote index increments; And transmitting the selected sequence as a main sync code (PSC), wherein any one of the first to fourth root indices is set to indicate specific cell ID related information in addition to the general cell ID. The fourth root index is divided into two pairs, the first pair and the second pair, and the sum of the root indices belonging to the first pair and the second pair is a cell corresponding to the generation length of the sequence transmitted as the main sync code. Provides a method of transmitting ID information.

In this case, the specific cell ID related information may indicate the cell ID information of the serving cell and the service attribute of the serving cell. In this case, the service attribute is whether the serving cell is a CSG Closed Subscriber Group cell, a relay station cell, MBMS (Multimedia Broadcast Multicast Service) indicator, may indicate one or more of the hot spot indicator. In addition, the cell ID information of the serving cell may be all or part of the serving cell ID information.

On the other hand, in order to solve the above problems, another aspect of the present invention provides a method of using a portion of the existing cell ID increase is reserved for additional physical layer cell ID information transmission.

In one embodiment there is provided a step of selecting a sequence having a root index of any one of the first to third root index; And transmitting the selected sequence as a main synchronization code (PSC), wherein any one of the first to third root indexes is configured to indicate specific cell ID related information in addition to the general cell ID. The sum of the root indices except for the root index indicating the specific cell ID related information other than the general cell ID among the third root index is based on the generation length of the sequence transmitted as the main sync code, and in addition to the general cell ID. The root index indicating the specific cell ID related information provides a cell ID information transmission method in which a sum with any one of other root indexes does not correspond to a generation length of a sequence transmitted as the main sync code.

In this case, the specific cell ID related information may indicate the cell ID information of the serving cell and the service attribute of the serving cell. Here, the service attribute may indicate whether the serving cell is a closed subscriber group (CSG) cell, a relay station cell, a multimedi broadcast multicast service (MBMS) indicator, or a hot spot indicator. Can be. In addition, the cell ID information of the serving cell may be all or part of the serving cell ID information. Yet another embodiment provides a method of selecting a first index ni ₀ and a second index y as a combination for distinguishing a cell group ID; And transmitting two sequences of length M according to the selected first index and second index combination (m ₀ , m) as two sub-sync codes, wherein the selected (m ₀ , _mi ) is selected. In the case of belonging to the first set group, the two sub-synchronization codes indicate specific cell ID related information in addition to the general cell ID. When the selected ( _mo , _mi ) belongs to the preset second group, the two floating channel codes are General cell ID information, and the first group includes two M-length sequence combinations, and indexes overlapping each index included in the combination of (m ₀ , mi) and (rm, m ₀ ) among all possible combinations. Cell ID information including a minimum, and a combination of a number of combinations satisfying a condition where the difference between m ₀ and t is minimum, and a combination of a number of combinations necessary to represent specific cell ID related information other than the general cell ID; Provide a transmission method. In the present embodiment, when the first group is additionally set to an existing combination of (mo, mi), it may be regarded as adding cell ID information according to an aspect of the present invention. In the case of a combination reserved for additional information transmission in the set (nio, n) combination, it may be viewed as a form in which part of the existing cell ID information is reserved according to another aspect of the present invention.

Advantageous Effects

According to the embodiments of the present invention described above, it is possible to efficiently transmit additional physical layer cell ID information while minimizing the influence on the existing system. As the cell ID information, various information as well as CSG cell ID information and repeater cell ID information may be transmitted.

[Brief Description of Drawings] 1 shows an example of a radio frame structure using a general CP normal cyclic prefix.

2 shows another example of a radio frame using an extended CKextended CP). 3 shows an example of mapping a sequence to a subcarrier region in a P-SCH.

FIG. 4 is a diagram conceptually illustrating two short code combinations used in a 3GPP LTE system among all the short combinations of two short codes available for S-SCH.

FIG. 5 is a diagram illustrating a concept of main synchronization signal based scrambling and segment 1 based scrambling performed to solve an ambiguity problem of floating signal transmission in a 3GPP LTE system.

6 is a diagram for describing a neighbor search scenario.

7 is a diagram illustrating a structure of a multi-absorption relay system to which a cell ID extension / reservation method according to each embodiment of the present invention can be applied.

8 is a diagram illustrating a time relationship between an SSS and a PSS in a frame.

9 is a diagram illustrating a method of transmitting additional information by changing a time position between an SSS and a PSS according to an embodiment of the present invention.

FIG. 10 is a diagram for describing a problem that may occur when only the synchronization signal swapping method is used.

FIG. 11 is a diagram for describing a delamination problem that may occur when the same PSS based scrambling code is used for an auxiliary sync signal.

[Form for implementation of invention]

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is illustrative of the present invention. It is intended that the embodiments be described and are not intended to represent the only embodiments in which the invention may be practiced.

The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details. In some instances, well-known structures and devices are omitted or shown in block diagram form with the core functions of each structure and device being avoided in order to avoid obscuring the concepts of the present invention. In addition, the same components throughout the present specification will be described using the same reference numerals.

The following techniques can be used in various wireless communication systems. Wireless communication systems are widely deployed to provide various communication services such as voice, packet data, and the like. This technique can be used for downlink or uplink. In general, downlink means communication from a base station (BS) to a user equipment (IE), and uplink means communication from a terminal to a base station. A base station generally refers to a fixed station communicating with a terminal, and may be referred to in other terms such as a node-B, a BTSCbase transceiver system, and an access point. The terminal may be fixed or mobile, and may be called by other terms such as MSCniobile station, UTdiser terminal, SS (subscriber station), and wireless device.

As described above, the present invention proposes a method for allowing a UE to easily perform discovery and identification of a CSG cell in an initial stage of cell discovery. To this end, first, the initial cell discovery process in the 3GPP or 3GPP 3rd Generation Partnership Project Long Term Evolution (LTE) system will be described. It will be discussed whether it is possible to enable the discovery and identification of additional cells while minimizing, specifically, as described above and whether to enable the discovery and identification of _CSG cells.

The 3rd Generation Partnership Project (3GPP) Wideband Code Division Multiple Access (WCDMA) system uses a total of 512 long pseudo noise scrambling codes to distinguish base stations. That is, the base stations use different long PN scrambling codes as the scrambling codes of the downlink channels.

When power is applied to the terminal, the terminal performs a process of system synchronization of the initial cell and obtaining a long PN scrambling code identifier of the initial cell. This is called a cell search process. Here, the initial cell is determined according to the position of the terminal when the power is applied, and generally means a cell of the base station corresponding to the largest signal component among the signal components of each base station included in the downlink received signal of the terminal. .

In a WCDMA system, 512 long PN scrambling codes are divided into 64 code groups to facilitate cell discovery, and a primary or primary synchronization channel (P-SCH) and a secondary or secondary synchronization channel are used. A downlink channel including a Secondary Synchronization Channel (S-SCH) is used. The primary synchronization channel is used to allow the terminal to acquire slot synchronization, and the secondary synchronization channel is used to allow the terminal to acquire frame synchronization and scrambling code groups.

In general, the cell search includes an initial cell search performed initially after the UE is powered on, and a non-initial cell search that performs handover or neighbor cell measurement. Separated by.

In the WCDMA system, the initial cell search method is largely performed in three steps. In the first step, a terminal acquires slot synchronization using a primary synchronization signal (PSS) transmitted through a P-SCH. In a WCDMA system, each frame includes 15 slots, and each base station transmits the PSS by including it in the frame. Here, the same PSS is used for all 15 slots, and all base stations also use the same PSS. The terminal acquires slot synchronization using a matched filter for the PSS.

In the second step, a long PN scrambling code group and frame synchronization are obtained by using a slot synchronization and a secondary synchronization signal (SSS) transmitted through the S-SCH.

In step 3, a long PN scrambling code identifier corresponding to a long PN scrambling code used by an initial cell is detected using a common pilot channel code correlator based on frame synchronization and a long PN scrambling code group. . That is, since eight long PN scrambling codes are mapped to one long PN scrambling code group, the UE calculates a correlation value of each of the eight long PN scrambling codes belonging to its own code group, and based on the calculated result, the initial cell. Detect a long PN scrambling code identifier.

Meanwhile, the wireless communication system may be a 0rthogonal frequency division multiplexing (0FDM) / 0rthogonal frequency division multiple access (0FDMA) based system. OFDM uses multiple orthogonal subcarriers. OFDM uses orthogonality between inverse fast Fourier Transform (IFFT) and fast Fourier Transform (FFT). At the transmitter, data is sent by performing an IFFT. The receiver performs FFT on the received signal to recover the original data. Transmitter to combine multiple subcarriers To use IFF! * And to separate multiple subcarriers, the receiver uses a vocal FFT.

1 shows an example of a radio frame structure using a normal CP (normal cyclic prefix).

Referring to FIG. 1, a radio frame includes 10 subframes, and one slot may include two slots. One slot may include a plurality of OFDM symbols in the time domain. The number of 0FOM symbols included in one slot may be variously determined according to the CP structure. In a radio frame using a general CP size, one slot may include 7 OFDM symbols. When the 0FDM symbol is 2048 Ts in a 10ms radio frame, a typical CP size may be 144 Ts (Ts = l / (1500O2048) sec).

The primary synchronization channel (P-SCH) is located in the last 0FDM symbol of the 0 th slot and the 10 th slot. The same primary synchronization signal (PSS) is transmitted through two P-SCHs. P_SCH is used to obtain time domain synchronization and / or frequency domain synchronization, such as 0FDM symbol synchronization and slot synchronization. ZS (Zadoff-Chu) sequence can be used as the PSS, there is at least one PSS in the wireless communication system.

ZC Sequence is one of the orthogonal CAZACCConstant Amplitude Zero Auto-Correlation sequences, where NZC is the positive integer length of CAZAC sequence, root index u is NZC and relative primeXu is a natural number below NZC. NZC and the prime number), the k-th element of the u-th CAZAC sequence can be expressed as the following equation (k = 0, l NZC-1). Equation 1 when N _zc is odd number

CAZAC sequence d (k) has three characteristics.

[Equation 2]

| ^ (/ 1 ⁼ 1 for all h Ν _ζσ u

[Equation 3]

[Equation 4]

In Equation 2, the CAZAC sequence always means that the size is 1, and Equation 3 means that the auto correlation of the CAZAC sequence is represented by a Dirac-delta function. Here autocorrelation is based on circular correlat ions. Equation 4 means that the cross correlat ion is always constant.

The P-SCH of the 3GPP LTE system is defined as a 62-length Zadoff-Chu sequence (hereinafter referred to as "ZC sequence") according to the following equation.

[Equation 5] e

Where the root index u of the ZC sequence can be given according to the following table. Table 1

Secondary Synchronization Channel (S-SCH) is located in the last OFDM symbol in the last C DM symbol of the 0 th slot and the 10 th slot. The S-SCH and the P-SCH may be located in contiguous OFDM symbols. Different SSSCSecondary Synchronization Signals may be transmitted through two S—SCHs. The S-SCH is used to obtain frame synchronization and / or CP configuration of a cell, that is, usage information of a general CP or an extended CP. One S-SCH uses two SSSs. M-segments can be used with SSS. In other words, one m-SCH includes two m-times. For example, when one S-SCH includes 63 subcarriers, two m-sequences of length 31 are mapped to one S-SCH. The m-sequence is one of the PN sequences, and the PN sequence is similar to the random sequence (^ 1 001 sequence) while being reproducible. The PN sequence has the following characteristics: (1) The repetition period is much longer. If the iteration period is infinitely long, it is a random sequence.

(2) The number of 0's and 1's in one cycle are similar.

(3) Run length 1 is 1/2, 2 is 1/4, 3 is 1/8, and so on. The run length is the same number of consecutive numbers.

(4) The cross-correlation between each sequence is very small in one cycle.

(5) You can't play a whole sequence with a small piece of sequence.

(6) Playback can be performed by an appropriate playback algorithm.

PN-Siemens includes the m-sequence, the Gold sequence, and the Kasami sequence. In addition to the above-mentioned properties, m-Siemens has an additional property of side-lobe of periodic auto-correlation —1.

P-SCH and S-SCH are used to obtain physical-layer cell IDs. The physical layer cell ID may be represented by 168 physical layer cell ID groups and three physical layer IDs belonging thereto. That is, the total physical layer cell ID is 504, and is represented by a physical layer ID having a range of 0 to 167 and a physical layer ID having a range of 0 to 2 included in each physical layer cell ID group. Three ZC sequence root indexes representing physical layer IDs are used for the P-SCH, and 168 m-sequence indexes representing physical layer cell ID groups may be used for the S-SCH.

P-BCH (Physical-Broadcast Channel) is located in the 0th subframe in a radio frame. P ᅳ BCH occupies four 0FDM symbols starting from the 0th 0FDM symbol (symbol following P-SCH) of the 1st slot of the 0th subframe. The P-BCH is used to obtain basic system configuration information of the base station. P-BCH is It may have a period of 40ms.

2 shows another example of a radio frame using an extended CP. Referring to FIG. 2, 6 OFDM symbols are included in one slot of a radio frame using an extended CP as compared to the radio frame shown in FIG. 1 using a general CP. When the OFDM symbol is 2048 Ts in the 10ms radio frame, the size of the extended CP may be 512 Ts (Ts = l / (15000 * 2048) sec).

Even in a radio frame using an extended CP, the P-SCH is located in the last OFDM symbol of the 0th slot and the 10th slot, and the S-SCH is located in the last OFDM symbol immediately before the last 0FOM symbol of the 0th slot and the 10th slot. The P-BCH is located in the 1st slot of the 0th subframe in a radio frame and occupies 4 0FDM symbols starting from the 0th 0FDM symbol (symbol following the P-SCH) of the 1st slot of the 0th subframe. do.

3 shows an example of mapping a sequence to a subcarrier region in a P-SCH. FFT window size Nf = 64.

Referring to FIG. 3, a ZC sequence having a length of N _zc = 63 is mapped to 64 subcarriers including a DC subcarrier. The ZC sequence is sequentially mapped from the leftmost subcarrier such that the center element of the ZC sequence, here the 31st element P (31), is mapped to the DC subcarrier. A null value is inserted into a subcarrier (in this case, -32 subcarrier) to which a sequence is not mapped among mapping sections. The sequence P 31 mapped to the DC subcarrier is punctured.

Here, the left side and the right side refer to the left side as one side of the DC subcarrier for convenience, and the opposite side of the DC subcarrier as the right side, and is not necessarily limited to the illustrated position. The size of the FFT window of the P-SCH and the length of the ZC sequence can vary. As a result, the mapping scheme of the sequence may be variously changed. ZC sequence may be symmetrically mapped around the DC subcarrier in the time domain.

Meanwhile, a cell group ID and radio frame synchronization information may be transmitted to a secondary synchronization signal (SSS), and final information is transmitted by a combination of two short codes. The combination (m0, ml) of the two short codes indicating the cell group ID may be defined as follows.

[Equation 6]

A table of 168 cell group IDs using these two short code combinations is as follows.

Table 2

'"0 쒜'" 0 "h '« 0 m ₀ »h

0 0 1 34 4 6 68 9 12 102 15 19 136 22 27

1 1 2 35 5 7 69 10 13 103 16 20 137 23 28

2 2 3 36 6 8 70 11 14 104 17 21 138 24 29

3 3 4 37 7 9 71 12 15 105 18 22 139 25 30

4 4 5 38 8 10 72 13 16 106 19 23 140 0 6

5 5 6 39 9 11 73 14 17 107 20 24 141 1 7

6 6 7 40 10 12 74 15 18 108 21 25 142 2 8

7 7 8 41 11 13 75 16 19 109 22 26 143 3 9

8 8 9 42 12 14 76 17 20 110 23 27 144 4 10

9 9 10 43 13 15 77 18 21 111 24 28 145 5 11

10 10 11 44 14 16 78 19 22 112 25 29 146 6 12

11 11 12 45 15 17 79 20 23 113 26 30 147 7 13

12 12 13 46 16 18 80 21 24 114 0 5 148 8 14

13 13 14 47 17 19 81 22 25 115 1 6 149 9 15

14 14 15 48 18 20 82 23 26 116 2 7 150 10 16

15 15 16 49 19 21 83 24 27 117 3 8 151 11 17

16 16 17 50 20 22 84 25 28 118 4 9 152 12 18

17 17 18 51 21 23 85 26 29 119 5 10 153 13 19

18 18 19 52 22 24 86 27 30 120 6 11 154 14 20

19 19 20 53 23 25 87 0 4 121 7 12 155 15 21

20 20 21 54 24 26 88 1 5 122 8 13 156 16 22

21 21 22 55 25 27 89 2 6 123 9 14 157 17 23

22 22 23 56 26 28 90 3 7 124 10 15 158 18 24

23 23 24 57 27 29 91 4 8 125 11 16 159 19 25

24 24 25 58 28 30 92 5 9 126 12 17 160 20 26

25 25 26 59 0 3 93 6 10 127 13 18 161 21 27

26 26 27 60 1 4 94 7 11 128 14 19 162 22 28

27 27 28 61 2 5 95 8 12 129 15 20 163 23 29

28 28 29 62 3 6 96 9 13 130 16 21 164 24 30

29 29 30 63 4 7 97 10 14 131 17 22 165 0 7

30 0 2 64 5 8 98 11 15 132 18 23 166 1 8

31 1 3 65 6 9 99 12 16 133 19 24 167 2 9

32 2 4 66 7 10 100 13 17 134 20 25---

33 3 5 67 8 11 101 14 18 135 21 26---The order of the combination ( _m 0, ml) shown in Table 2 above can represent frame timing information. That is, (ηιθ, πιΐ) can mean the 0th (0n) s subframe random sync signal, and (ml ᅳ m0) can mean the 5th (5ms) sync signal.

Equation 6 and the above table within all possible combination ranges as a combination of (mO, ml)

The combination used as shown in Figure 2 is as follows.

4 is a diagram conceptually illustrating two short code combinations used in a 3GPP LTE system among all the short combinations of two short codes available for S—SCH. In FIG. 4, the segment 1 (Segmentl) means mO and the segment 2 (segment2) means ml. FT is frame timing, where FT = 0 means synchronization signal (SS) of Oms subframe, and FT = 1 means synchronization signal (SS) of 5ms subframe.

Assuming two short codes of the original length 31, and each code can transmit 31 pieces of information (number of sequence sets), a total of 31 * 31 = 961 cell group IDs (information) will be sent with the two code combinations. There is a number. However, in the example of Equation 6 and Table 2, since the number of cell group IDs is 168, the cell ID detection performance is designed to be maximized in consideration of inter-cell interference. In other words, 168 combinations were selected to give the best performance out of a total of 961 possible combinations.

As described above, the code may be referred to as SSCXSecondary Synchronization Code and is a circular shift of 31-length m-sequence generated from a polynomial of x ⁵ + x ² + l. ) Can generate a total of 31 sequences.

3 to reduce ambiguity between adjacent cells for the combination

Scrambling may be performed on the SSC with a scrambling sequence defined to be one-to-one with a Primary Synchronization Code (PSC). Here, if the cell A has a combination of (1, 2) as the SSC, and the cell B has a combination of (3, 4) as the SSC, when the terminal detects the synchronization signal (1,4), (3, 2) There is a possibility of incorrectly detecting a combination of This phenomenon is hereinafter referred to as "ambiguity".

At this time, cell A and cell B use different PSCs, and based on this PSC, When scrambling is performed, the combinations (1, 2) and (3, 4) may be strongly bound to reduce the probability of occurrence of the ambiguity described above. The PSC-based scrambling code is used to generate six different sequences by cyclic shift of a 31-length m sequence generated from a polynomial of x ⁵ + x ² + l, and in two units. Three PSC indexes as shown in Table 1 and those defined in a one-to-many correspondence relationship are used.

However, even if the PSC-based scrambling described above is applied, ambiguity may still be a problem. For example, if a neighboring cell A has a subsynchronization code combination having a (1,2) combination, a cell B transmits a subsynchronization code having a (3,4) combination, and both cells transmit the same PSC code. Suppose In this case, since the PSC codes used by the two cells are the same, the scrambling code applied to the floating channel code is also the same, so the ambiguity problem as described above still remains.

Accordingly, segment 1 based scrambling may be performed in addition to the PSC based scrambling as described above in order to strengthen the binding force of (1, 2) and (3, 4). In this case, the segment 1 represents the mO portion in the (m0, ml) combination, the segment 2 represents the ml portion as described above.

Segment 1 based scrambling refers to performing scrambling on the SSC of segment 2 with a scrambling code defined to correspond to the index of segment 1. Based on the case where the cell A uses the combination (1, 2) and the cell B uses the combination (3, 4) as in the above example, since the indexes 1 and 3 of the segment 1 are different codes, The defined scrambling code is also different, so that the above-mentioned ambiguity problem can be solved by strengthening the binding force of (1, 2) and (3, 4). The segment 1 based scrambling code used at this time is 31 length-based m generated from a polynomial of ⁵ + ( ⁴ ½ ² + ^ + 1 Eight different sequences are created by circular movement of the sequence, and are defined and used in a one-to-many correspondence with the index used for segment 1. That is, in the 3GPPLTE system, each segment is mapped to a segment 1 based scrambling sequence based on modulo 8. More specifically, the definition of the SSC and the scrambling code mentioned in the above description may be expressed as follows.

The 62 length sequence ^ (0) ni (61) used for the secondary synchronization signal (SSS) is used as an interleaved connection sequence of two 31 length binary sequences. In this case, the interleaved connection sequence may be scrambled with a scrambling sequence given by a primary synchronization signal (PSS).

Meanwhile, two 31-length sequence combinations defining the SSS are defined differently in subframe 0 and subframe 5 as follows.

[Equation 7]

N is an integer based on 0-30 here. MO and ml in Equation 7 are defined by Equation 6 by the physical layer cell ID group N _ID ⁽¹⁾ . For convenience, this is expressed again as Equation 8 below.

[Equation 8] = »Mod31

The results are as shown in Table 2 above. On the other hand, m sequence in the following manner used in the equation (7)

Is defined as two different circular movements of.

[Equation 9]

S, n) 二 sU + m Qr, _j ) 丄 m ij_wod 31)

Where A ¾ ^(where 'Ο ^ ί ^ ΒΟ is defined as

Equation 10 x (i + 5) 二 (xQ + 2) + j /) Jmod 0 <<25

Here, the initial values are x (0) = 0, x (l) = 0, x (2) = 0, x (3) = 0, and x (4) = 1.

On the other hand, the two scrambling codes c ₀ ⁽ ") and in Equation 7 depend on the main synchronization signal (PSS), and can be defined as two different cyclic shifts of the following m sequence"). [Equation 11] c ₁ (n) = c ((n + N _l § +3) mod 31) where the primary synchronization channel signal in the physical layer cell ID group N _ID ⁽¹⁾ as shown in Table 1 above. According to N _id ⁽²⁾ satisfies ^ g ^ i ^ ² }, £ ΰ = ι— <0 ^(where 0 <ί: ≤30) is defined as

[Equation 12] χ (ϊ +5) = (χ (ί + 3) + χ (ϊ)) πιοά2, 0 </ <25

The initial values are χ (0) = 0, χ (1) = 0, χ (2) = 0, χ (3) = 0, and χ (4) = 1.

On the other hand, scrambling of the equation (7) and is defined as the circular movement of m sequence ^ O) according to the following relationship.

[Equation 13]

+ ( _mQ mod S)) mod 31) zf ¹ ' ⁾ (n) = z ((¾ + (m _l modS)) mod 31) where m ₀ and "are obtained by Table 2 above,

(Where 0 ≦ ί ≦ 30) is defined from the following relationship.

[Equation 14] χ (+ 5) = (χ (ϊ + 4) + x (i + 2) + χ (ϊ + 1) + ^ (^ mod ^ 0 <<25 Here, the initial value is ⁰ ) ^ ¾ ^χ Φ "¾ ^ (2)-0, = 0, 1. This process is as follows.

Specifically, 501a and 501b of FIG. 5 represent scrambling codes zl based on segment 1 as shown in Equation 13, and 502a and 502b represent scrambling codes based on PSC. Such two types of scrambling can solve the ambiguity problem that can occur in SSC transmission.

The final cell ID is a combination of N _ID ⁽²⁾ and SSS _ID of N ⁽¹⁾ in the PSS

= ^{3N + N} §, currently 504 (= 3 * 168) are defined.

Meanwhile, as a problem in acquiring the cell ID information of the UE, the above-mentioned ambiguity problem as well as the delamination problem may occur. In the following, this problem of delamination is explained. This problem of stratification is a story about a case where two or more SSSs are accumulated and searched.

For ease of explanation, it is assumed that two SSC combinations of cells A = (S11, S12) and cells B = (S21, S22). In the combination (a, b), a represents the SSC index of segment 1, and b represents the SSC index of segment 2. Assume that the PSC indexes of two cells are the same. In addition, it is assumed that two S-SCH signals are accumulated in one frame. As shown in Equation 7, since SSSs transmitted in subframe 0 and subframe 5 are in a swapping relationship, cells A = (S11, S12, S12, S11), cells B S21 ᅳ S22, S22, S11). For a more specific example of this case, say a cell A = (l, 2, 2, l), cell B = (l, 3, 3, l), the interference between them is (a, b , b, a) to have a Hamming distance of 2. Where index is the interference between 1 and 1, and b is the interference between 2 and 3. The collision of 1 and 1 means collision, which remains intact in subsequent subframes. In other words, the same interference is repeated during the accumulation period so that the effect of interference randomization is lost. This phenomenon is defined as "collision problem" in this document.

In this example, since it is assumed that cell A and cell B have the same PSC index, the expression to which the same PSC-based scrambling code is applied will be omitted for convenience. Applying segment 1 based scrambling under these assumptions, cell A = (l, c (l) * 2,2, c (2) * l) and cell B = (l, c (l) * 3,3, c ( 3) * 3). Therefore, the interference between both cells becomes (a, b, c, d), and the Hamming distance is 3 except that 1 is first layered. In other words, the interference of all combinations are all different, so that the maximum interference randomization effect can be obtained.

That is, the above-mentioned dolmen problem can also be solved by PSC based scrambling and segment 1 based scrambling. Based on this description, the neighbor search scenario is as follows.

6 is a diagram for describing a neighbor search scenario.

That is, the UE located at the cell boundary receives the PSCa (Pa) and the SSCa (Sla and Sib) from the cell A, and receives the PSCb (Pb) and the SSCb (S2a and S2b) from the cell B. Eight possible scenarios in this situation can be represented as in Table 3 below.

Table 3

Here, "Phase mismatch" means a phase mismatch that occurs when the signals from two cells are misaligned (when misaligned). Therefore, it is preferable to design the cell in consideration of the scenario shown in Table 3 above.

Meanwhile, the cell ID extension / retention method according to embodiments to be described below according to the present invention describes a femtocell or a CSG which is discussed in a 3GPP LTE system as a main example. However, the method according to these embodiments may be used for the extension or reservation of the repeater ID under consideration by a standard body such as LTE-A or IEEE802.16m according to the same principle. That is, in the description of the present invention, the expansion and reservation of the cell ID may be used for identification information for any object, and the femtocell or CSG ID described in each embodiment may be replaced by a relay ID. .

The following briefly describes the relay station.

For ease of explanation, the repeater considered in IEEE 802.16j is described, but the same applies to the relay station considered in 3GPP IMT-A (LTE-A).

IEEE 2006, IEEE IEEE Institute of Electrical and Electronics Engineers (IEEE) IEEE 802.16, IEEE standard for fixed subscriber stations After the publication of 802.16-2004 and IEEE 802.16e-2005, a standard standard for providing mobility of subscriber stations, a standardization project under the new theme of multi-absorption relay is in progress. The project, which is undertaken by Task Group j within IEEE 802.16, has held its first official meeting in May 2006, and in its second jubilee in July, the Usage Model, terminology and technical requirements. (Technical Requirement) has begun to discuss in earnest. (Sometimes referred to as 802.16 j, abbreviated as 802.11 TGj)

Working Group J's PAR (Projec- tive Authorization Request) within IEEE 802.16 specifies two objectives of the future standardization work. The two objectives are Coverage Extension and Throughput Enhancement.

In Fig. 7, reference numeral 7 (31 denotes a base station, reference numerals 702a to 702d denote a relay, and reference numerals 703a to 703d denote a terminal), as shown in Fig. 7, an area outside the area of the base station 701. In addition, signal transmission through the relay stations 702a and 702b may be possible, and a high level of adaptive modulation and coding through the relay station 702d may be provided to the terminal 703d within the area of the base station 701. By enabling the establishment of a high quality path having a scheme, it is possible to increase system capacity with the same radio resource.

The standard that will be created by this project is based on the existing 802.16-2004 and 802.16e-2005 standards. Under the principle that communication with the relay station should be possible, the scope will be limited by addition of some functions for controlling the relay station to the relay station itself and the existing base station. Therefore, specifications for relay stations are expected to be a key issue for future standardization.

The relay station can be thought of as a kind of subscriber station that performs the operations of the physical layer and the media access control layer. The relay station is mainly controlled by the base station, but if necessary, it can have some control function. Currently, the witness utilization model considers not only fixed relay stations, but also mobile relay stations for temporary services to specific areas, and relay stations that can be mounted in cars or subways.

Representative technical issues to be discussed in the future can be summarized as follows.

The base station identifies the relay stations in its area and connects them

procedures for obtaining and maintaining information on topology

* Definition of physical transmission frame structure between mobile station and relay station with backward compatibility with existing IEEE 802.16 / 16e system

* Signaling procedure for providing mobility between relay stations or between relay stations and base stations

* Network entry procedure of relay station to base station and entry procedure through relay station of mobile terminal

In addition, there may be many technical issues, but compatibility with existing systems is expected to be the biggest obstacle in solving these problems. As mentioned earlier, the principle that all terminals implemented according to the standards of 802.16-2004 and 802.16e-2005 should be able to communicate with the base station through the relay station without any additional function is almost defined in the existing two standards. It is a constraint that all functions must be possible through the relay station, and it can also act as a factor to increase the complexity of the relay station. Because there is. Therefore, how to solve this problem is expected to greatly affect the speed and marketability of standardization in the future.

On the other hand, WiFi is by far the most widely used access point for home / business use. However, even in such a WiFi environment, there is an increasing demand for a new dual mode (WiFi / GSM or WiFi / UMTS) UE, and sooner or later, access points such as CSG (Hum Node B or femtocell) are compatible with existing UEs and are widely used. It is expected to be.

Accordingly, such a UE should be able to identify CSGs that are allowed to access efficiently, and UEs that are not allowed to access CSGs should avoid any measurement with the CSG to prevent unnecessary signaling and power consumption. Do.

Embodiments according to the present invention to be described below provide various methods for solving the problems as described above. Hereinafter, the following two aspects will be described based on the provisions of the current 3GPP LTE standard.

1. How to increase the total number of 504 physical cell IDs

2. How to reserve some of the total number of 504 physical cell IDs as cell IDs for CSG In principle, it is desirable to increase the number of physical cell IDs for newly introduced CSG cells. It may not be easy to add such a physical cell ID on the schedule. To this end, in the first aspect of the present invention, a method of reserving some of the existing 504 physical cell IDs for the CSG cell will be described, and on the assumption that the extension of the physical cell ID for the CSG cell is possible, Side 2 looks at how to add a physical cell ID with minimal impact to existing cells and UEs. However, the first and second aspects of the present invention to be described below are not only the CSG physical cell ID in the 3GPP LTE system, but also the physical cell ID, MBMS indicator, and hot spot indicator (hot spot indicator) used in the IEEE system. -spot indicator) can be applied by the same principle as described above.

In the following description, the cells are classified into CSG cells and macro-cells, and it is assumed that the macro-cells refer to cells that are not CSG cells.

I. 1st aspect-M to reserve and use currently defined physical cell ID for CSG cell

According to the current 3GPPLTE standard, 168 cell group IDs are defined according to the SSS, and three cell IDs within each group are defined according to the PSS, so that a total of 504 (= 168 * 3) physical cell IDs are defined. In the following embodiments, a description will be given of a method of setting and retaining a portion of each of them for a CSG cell.

1) How to reserve PSS

For example, in one embodiment of the present invention, one of three currently defined PSCs is reserved as a cell ID for CSG. In an embodiment of the present invention, the complex symmetry characteristics of the PSCs among the indices of 25, 29, and 34 of Table 1 are used. It is proposed to reserve 25 for CSG except 29 and 34 to satisfy the CSG. That is, 29 and 34 satisfy a symmetric relationship with each other based on the generation length 63 of the ZC sequence used for the PSC, and the generated PSCs satisfy a complex symmetric relationship with each other. Thus, two PSCs satisfying a complex symmetric relationship are adjusted by only the +/- operation of the intermediate values generated in the correlation value calculation step with one PSC, rather than searching through the correlation with each PSC at the receiving end. Can be detected by one operation.

The complex symmetry characteristic described above will first be described in order to examine the method in more detail.

As mentioned in connection with Table 1, the root index (u) of the ZC sequence constituting the PSC in the current 3GPP LTE system is 25, 29, 34. On the other hand, for the root index of the ZC sequence that makes up the PSC,

When two root indices satisfying (where N _zc is ZC sequence generation length) are applied, two ZC sequences are expressed as in Equation 15 below.

Equation 15 N _zc . is odd mimber

Z N _zc is even numb,

In the case of having a relationship as shown in Equation 15, the correlation output for _Ul and _U2 has a similar amount of calculation as ui one correlation result, and the correlation result for L and U ₂ for time synchronization in one operation. Can be calculated. As described above, two ZCs satisfying i + u ^ Nzc satisfy the complex symmetry relationship or the junction symmetry relationship. Alternatively, ZC, which can yield a correlation result between _Ul and u ₂ in one operation, is called a complex symmetry relationship or a joint symmetry relationship.

On the other hand, the junction symmetry of ZC Sieux is not only in the frequency domain but also in the time domain. maintain. Thus, the PSS can be transmitted not only in the frequency domain but also in the time domain.

Suppose that ZC sequence when N _zc is odd is mapped and transmitted to the time domain in the same manner as in FIG. 3. If the time domain signal at this time is a ^u (k), the value of the intermediate buffer (intermediate buffer) for calculating the final correlation value is defined as in Equation 16 below.

[Equation 16]

Here, r (n) represents the received signal, d represents the delay index, and I and Q represent the I component (in-phase) and Q component (quadrature-phase) of the complex signal.

Accordingly, the final correlation result of and u ₂ can be expressed by Equation 17 below.

[Equation 17]

As described above, the joint symmetry relationship of the PSS may be maintained not only in the frequency domain but also in the time domain. Therefore, in the present embodiment, when there is a combination that satisfies the predefined PSC complex symmetry characteristic using a feature described above and a combination that does not, the PSC that does not satisfy the complex symmetry characteristic is reserved for the cell ID for CSG. It is proposed to represent a CSG cell using this.

2) How to reserve SSS

In case of CSG cells, the following interference relationship should be considered.

(1) Interference Between Macrocells

(2) Interference between macro cell and CSG cell

(3) Interference between CSG cells

Similarly, in the case of repeaters, the following interference relationship should be considered.

(1) Interference Between Macrocells

(2) Interference between macro cell and repeater cell

(3) Interference between repeater cells

Since the considerations in each case are the same, only the CSG cell will be described below.

In terms of cell ID detection, the effects of interference are described above in the "ambiguity problem." (ambiguity problem) ". Among the three interferences described above, (1) the interference between macrocells is already minimized when selecting 168 SSC combinations in the current 3GPP LTE 3rd Generation Partnership Project Long Term Evolution (LTE) standard. Of course, it doesn't solve the interference problem in all cases, but since 168 SSCs are defined, three sectors (black sectors, six sectors, etc.) within one CSG cell can be used to create a proper plan. Through the above (1), it is possible to optimize in terms of (2).

However, in case (3), a problem may occur for the CSG cell. For convenience, it is assumed that 50 cell IDs are reserved in the CSG cell. In general, the coverage of a CSG cell is several tens of meters, there is no sector concept, and it is possible to install multiple CSG cell base stations within a region, so that about 50 CSG cells solve (3) intra-femto interference. Difficult to do In other words, it is difficult to plan a cell because the number of cell IDs for CSG cells is too small.

In addition, in the description of the present embodiment, 50 IDs reserved for CSG cells are described as an example, but need not be limited to the number, but the interference between CSG cells may be more important than the interference in macro cells. .

Therefore, when the SSS index is reserved for the CSG cell, both the ambiguity problem between the CSG cells and the stratification problem should be considered. This embodiment proposes a CSG cell ID reservation method for solving the above-described ambiguity / stratum collision between CSG cells.

Assuming that there are 50 CSG cells, since there is no sector concept for the CSG cells, a number of cases in which a signal having the same PSC is received from the UE is generated. In this case, three solutions for solving the ambiguity as mentioned with respect to the macro cell (1. PSC-based scrambling of SSC diagonal pairing (see FIG. 4), 2. PSC-based scrambling, and 3. segment 1 based scrambling does not provide much help in solving the ambiguity problem.

Therefore, the present embodiment proposes the following reservation priority so that the above ambiguity problem can be solved only by the cell group ID indicated by the SSS regardless of the PSC. In the following description, it is assumed that the SSC1 portion is segment 1 and the SSC2 portion is segment 2 in the SSC pairs SSC1 and SSC2.

First, it is assumed in this embodiment that segment 1 based scrambling should be effectively applied to solve the ambiguity problem and the delamination problem. In this case, the segment 1 based scrambling should be effectively applied considering the swapping relationship.

Second, if it is difficult to apply the segment 1 based scrambling as described above, it is assumed to apply a diagonal pairing concept to solve the ambiguity problem.

In order to solve the ambiguity problem, it is assumed that 20 cell IDs are reserved as (0,1), (0,2), (0,3) .. (0,20) as cell IDs for CSG cells. In this case, there is no ambiguity problem for any combination.

However, since one SSC uses the same index, the total correlation value is reduced to 1/2. For example, suppose two cells use a combination of (0, 1) and (0, 2), respectively. Then, since the same index 0 is used in segment 1, the total correlation is 1/2. When accumulating two SSCs, (0, c (0) * l, 1, c (l) * 0), (0, c (0) * 2, 2, c (2) * 0) This results in a full correlation of 1/4 (ie 00,000 stone). In this case, the correlation value is intuitively increased by increasing 1 when the same index is used. It is calculated.

In addition, the interference is in the form of (a, b, c, d), and the Hamming distance is 4, so there is no delamination problem. However, since the correlation value increases, the present embodiment proposes a method of suspending segment 1 based scrambling first and then diagonal pairing first.

Also consider the case of using a combination of (0 1) and (7, 8). This combination further entails a delamination problem in addition to the 1/2 correlation problem mentioned above. For example, the receiver swaps (i.e., (0, c (0) * l, 1, c (l) * 0), (7, c (7) * 8, 8 c (0) * 7)) Hypotheses for 0th or 5th subframe should be performed. That is, assume that the received signal is (0, c (0) * l, l, c (l) * 0), and assume for (7, c (7) * 8,8, c (0) * 7). If you do not have ambiguity and dolb problem. However, assume that the received signal is (0, c (0) * l, l, c (l) * 0) and make assumptions for (8, c (0) * 7,7, c (7) * 8). If performed, ambiguity problems will occur for the parts shown in bold text (ie false alarms with (07) or (8,1) combinations). This problem occurs because the number of scrambling codes defined by segment 1 based scrambling is determined to be eight through the Modler 8 operation of the SSC index.

In addition, examples of (0 1) and (8, 9) will be described. Ambiguity for parts marked in bold by (0, c (0) * l, l, c (l) * 0), (8, c (0) * 9,9, c (l) * 8) A problem arises. Also, in bold type for (0, c (0) * l, l, _c (l) * 0) and (8, c (0) * 7,7, c (7) * 8) for the swapping assumption There is a ambiguity problem with the markings.

Therefore, the following method is proposed in this embodiment.

(1) If segment 1 based scrambling is a combination that can be applied differently, It is desirable for all indexes in the reserved set to be different.

(2) If an additional cell ID other than (1) is needed, it is preferable to select to solve the ambiguity problem. That is, a summary of a method of retaining Nf cell IDs for CSG cells is as follows.

(1) All indexes are different in terms of mod (M) for all (mO, ml) SSC combinations (including cross combinations) in order to be effectively applied, even when segment 1 based scrambling is swapped. Select. Where M is the number of scrambling defined. That is, the cell

ml), cell B = (m2, m3), mod (mO, M) ≠ mod (m2, M), mod (raO, M) ÷ mod (m3, M), mod (ml, M) ≠ mod It is proposed to choose to satisfy (m2, M), mod (ml, M) ÷ mod (m3, M).

In a specific example according to the present embodiment, it is considered to start from a combination where the distance between mO and ml is one difference. That is, in the case of Table 2 (mO, ml) = (0, l), (2, 3),

It is proposed to reserve four cell group IDs such as (4,5) and (6,7). This corresponds to selecting indices 0, 2, 4, and 6 of N _ID ⁽¹⁾ in Table 2 above,

12 (= 3 * 4) physical cell IDs can be reserved.

(2) On the other hand, if more cell IDs are needed, based on the selection in (1), the SSS selects to overlap only once from the viewpoint of Modler for all cross combinations due to the swapping characteristics in each subframe. As a specific example, it is also assumed that in this case, a combination in which the distance between mO and nil is different by 1 is selected. That is, it is proposed to select the indexes 1, 3, 5, and 7 of the N _ID ⁽¹⁾ following the indexes 0, 2, 4, and 6 of the N _ID ⁽¹⁾ selected in the above (1). That is, four cell group IDs such as (mO, ml) = (0, l), (2,3), (4,5), (6,7) Additionally, a total of 8 cell group IDs are selected by selecting 4 cell group IDs such as (! 110,1111) = (1,2), (3,4), (5,6), (7,8). Suggest that. Accordingly, 24 (= 3 * 8) cell IDs can be reserved for CSG cells.

(3) If more cell IDs are needed, select all overlapping combinations as described above based on the selection in (2) so as to overlap only once from the Modular point of view. In a specific embodiment according to the present embodiment, it is proposed to select an additional combination among combinations in which the distance between mO and ml differs by two. That is, in (2), N _ID ⁽¹⁾ index 0, 1, 2, 3, 4, 5, 6 in Table 2, followed by indexes 30, 31, 32, 33, 34, 35 of N _ID ⁽¹⁾ . , We propose to select 36 additionally, according to (2) (mO, ml) = (0, l) _I (2,3), (4,5), (6,7), (1, (8,2), (1,3), (2,4), (3,5) to eight cell group IDs such as 2), (3,4), (5 ᅳ 6), (7,8) ), Additionally select 7 cell group IDs such as (4,6), (5,7), (6, 8) to add a total of 15 (= 8 + 7) cell group IDs, i.e. 45 (= 3 * It is proposed to reserve 15) cell IDs for CSG cells.

(4) If necessary, further select combinations that overlap only once from the Modler point of view, based on the selections made up to (3). In a specific example according to the present embodiment, it is assumed that the distance between mO and ml is selected to be 3 different. That is, following (3), it is assumed that the indexes 59, 60, 61, 62, 63, and 64 of N _ID ⁽¹⁾ are additionally selected in Table 2 above. That is, (mO, ml) = (0, l), (2,3), (4,5), (6,7), (1,2), (3,4), ( 5,6, (7,8), (0,2), (1,3), (2,4), (3,5), (4,6), (5,7), (6 (M) = (0,3), (1,4), (2,5), (3,6), (4,7), (5,8) It is proposed to add a total of 21015 + 6) cell group IDs by adding 6 cell ID groups such as). Accordingly, a total of 630 = 3 * 21) cell IDs can be reserved for CSG cells. (5) In case of further need, based on the choices made up to (4), it is proposed to additionally select a combination that overlaps only once between segments in consideration of the intersection combination from the Modler point of view. The example according to the present embodiment proposes to select a combination combination with a difference of 4 between mO and ml, i.e., following (4), index 8 of N _ID ⁽¹⁾ in Table 2 above. The 88 89, 90, 91 is further selected, and 5, such as (mO, ml) = (0,4), (1,5), (2,6), (3,7), (4, 8) It is proposed to additionally select two cell group IDs. Accordingly, 26 (= 21 + 5) cell group IDs can be reserved, and a total of 78 (= 3 * 26) cell IDs can be reserved for CSG cells.

(6) If necessary, select additional combinations so that each segment overlaps only once from the Modular point of view based on the choices made up to (5). In this example, it is proposed to further select a combination having a distance between mO and ml of 5, and accordingly, further select indexes 114 and 115 116 117 of N _ID ⁽¹⁾ in Table 2 above. This results in (m0 ₎ ml) = (0,5), (l, 6), (2 ₎ 7) ₎ (3 ₎ 8) 7> totaling 30 (= 26 + 4) cell group IDs, ie 90 (= 3 * 30) cell IDs can be reserved for CSG cells.

(7) If necessary, select additional combinations of overlapping only once between segments from the Modular point of view, based on the choices made to (6), in this example adding an additional combination with a distance of 6 between mO and ml. Suggest. That is, it is assumed that the indexes 140 and 141 142 of N _ID ⁽¹⁾ in Table 2 are further selected after (5), and (^, 1111) = (06), (17), and (2,8). You can add a cell ID group such as Accordingly, a total of 33 (= 30 + 3) cell group IDs and 9903 * 33) cell IDs can be reserved for CSG cells.

(8) If necessary, based on the choices made up to (7), combine only one overlap between each segment from the Modular point of view, especially the combination with a distance of 7 between mO and ml. Suggest to add. That is, in Table 2, indexes 165 and 166 of N _ID ⁽¹⁾ may be added, that is, (m0, nil) = (0/7), (l, 8). Accordingly, a total of 35 (= 33 + 2) cell group IDs, that is, 10503 * 35 cell IDs can be reserved for the CSG cell.

That is, in the present embodiment, the cell IDs are used as needed in such a manner that the cell group IDs are selected and used in the order in which the distance between the two segments is minimized, while not overlapping as much as possible in consideration of the modular operation. You can add

The concept according to the present embodiment described above is expressed by a Mat lab algorithm as follows.

Matlab Algorithm 1

N_d: distance between m_0 and n

M: number of segl—based scrambling codes

% program start

M = 8; % for this exam le

nb start = 0; % this value can be changed such as m_start = l or nb start = 10, etc

MatSetCSG = [];

N_d = l;

while M-N_d> 0,

for ii = 0: M- (N_d-l) -l,

MatSetCSG = [MatSetCSG; nb start + ii nb start + ii + N_d];

end% end of for, ii N_d = N_d + l;

end% end of while

%% program end

The MatSetCSG (ie, selected combination) generated by the Matlab algorithm 1 is as follows.

MatSetCSG = [

1 5

2 6

3 7

4 8

0 5

1 6

2 7

3 8

0 6

1 7

2 8

0 7

1 8

];

Here, 35 cell group IDs can be reserved and can be reserved for a total of 105 CSG cells. If one attempts to reserve less than 105 cell IDs (eg, Nx), Nx of the combinations may be selected and used for CSG cells. For example, to reserve 51 cell IDs, a total of 51 cell IDs can be reserved by selecting 17 cell group IDs and retaining them for CSG cells. By selecting and retaining the number of cell group IDs, a total of 48 cell IDs can be reserved.

At this time, it is preferable to select the desired number of IDs in the order of generation, but it is assumed that the present embodiment does not have such a constraint. For reference, m_start = 0 in the initial value of Matlab algorithm 1, and this value can be changed. For example, if m_start = l, the result is as follows.

MatSetCSG = [

12

ι

Also, in another embodiment of the present invention, two SSCs are swapped

Considering this, the Mat lab algorithm 1 can be modified as follows.

Matlab Algorithm 2

R—d: distance between m_0 and m_l

M: number of segl-based scrambling codes% program start

M = 8; % for this example

¾_start = 0; % this value can be changed such as m_start = l or nb start = 10, etc

MatSetCSG = [];

N_d = l;

while M-N_d> 0,

for ii = 0: M- (N_d-l) -2,% this part has been changed.

MatSetCSG = [MatSetCSG; nb start + ii n start + ii + N_d]; end% end of for, ii

N_d = N_d + 1;

end% end of while

Wo program end

The set selected according to the Mat lab algorithm 2 is as follows.

Ma ^t seG ^t cs 37

0 5

16

27

06

17

07

]

That is, 28 cell group IDs are selected, and a total of 84 cell IDs are proposed to be used for CSG cells.

In another embodiment of the present invention, different indexes are reserved for all combinations (including cross combinations), so that ambiguity does not exist in all candidates. To this end, it is possible to set two criteria:

Segment 1 based scrambling selects different indexes to solve the ambiguity problem. At this time, all selected combinations should be composed of different indexes. The reason for doing this is to solve not only the ambiguity problem but also the ambiguity problem when the mO and ml are swapped.

* If the number of segment 1 based scrambling is limited, the case of a combination with ambiguity between the limited combinations is deleted if it belongs to all candidates.

For example, an index of N _ID ⁽¹⁾ of 0, 2, 4, ..., 28 is selected from the SSC table as shown in Table 2 above. (mO, ml) can be expressed as (0,1) (2,3) (4,5) (6,7) (8,9) (10,11) (12,13) (14,15) (16,17) (18,19) (20,21) (22,23) (24,25) (26,27) (28,29)-> 15

Thereafter, if the number of segment 1 based scrambling is 8, the SSC combination may be classified into the following four groups.

Group 1: (0,1) (2,3) (4,5) (6,7)

Group 2: (8,9) (10,11) (12,13) (14,15)

Group 3: (16,17) (18,19) (20,21) (22,23)

Group 4 :： (24,25) (26,27) (28,29)

Applying segment 1 based scrambling solves the ambiguity problem within each group. However, there may be ambiguity problems between groups. For example, in (0,1) of group 1 and (8,9) of group 2, since 0 and 8 use the same segment 1 based code, ambiguity problems of (0,9) or (8,1) may occur. Can be. However, since (0,9) or (8,1) (a swapping form of (1,8)) are not included in the 168 SSC tables shown in Table 2, no ambiguity problem occurs. Thus, the final selected combination is as follows.

(0,1) (2,3) (4,5) (6,7) (8,9) (10,11) (12,13) (14,15) (16,17) (18,19) (20,21)

(22,23) (24,25) (26,27) (28,29)-> 15

Therefore, a total of 3 * 15 = 45 cell IDs can be reserved for CSG cells.

Of course, in the present invention, a cell ID for a CSG cell may be reserved and used by a method combining the above-described embodiments.

On the other hand, the following describes the case of using the CSG cell ID separately from the existing physical cell ID. Π. Second Aspect-How to Increase Physical Layer Cell ID

1) How to increase the number of indexes of Secondary Synchronization Signal (SSS) Currently, the following three concepts have been introduced to minimize the ambiguity problem in the combination of two short codes in the SSS in the 3GPP LTE standard.

Diagonal SSC pairing (see FIG. 4)

PSC-based scrambling

Segment 1 based scrambling

Without considering the diagonal SSC pairing, a total of 961 (= 31 * 31) pieces of information that can be transmitted by using a combination of two 31 short codes used in the current SSS. On the other hand, considering that SSC pairs transmitted at 0 ms and 5 ms are swapped with each other as shown in Equation 7, the number of possible sequence combinations is 465 (= ₃ iC ₂ ). Currently, the 3GPPLTE standard defines 168 as two SSC combinations. Thus, considering only swapping of SSC pairs transmitted at 0 ms and 5 ms, 297 (= 465-168) SSC pairs can be added. have. In this way, when the SSC is added, the total number of cell IDs can be extended to 1395 (= 465 * 3).

However, if the SSC pair is extended to a certain level smaller than 465, not up to 465, it should be designed considering the following HeNB cell (CSG cell) characteristics. In other words, if a cell ID is assigned to a macro-cell, interference by a cell having the same PSC code is usually insignificant. (In other words, if there are 57 cells in total considering 2 tiers, and cell planning is well done, only 9 cells will be subjected to weak interference.)

However, the CSG cell has a small cell coverage (typically tens of meters) and the sector concept. Since it cannot be introduced, it is an important issue to solve the ambiguity or stratification problem for all possible sequence combinations.

The basic principle applied to the SSC addition method according to the present embodiment is the same as the principle in the above-described method of using the reserved SSS of the first aspect of the present invention for the CSG cell. If only there is a difference, the cell ID defined as shown in Table 2 is left as it is to be defined to solve the ambiguity and stratification problem for the newly defined cell ID for CSG cells.

The basic principle is the same, so I will explain it only from the Matlab algorithm point of view.

Matlab algorithm 3

N_d is the distance between m_0 and n

M is the number of segl-based scrambling codes

%% program start

M = 8; % for this exam le

ii! Lstart = 0; % this value can be changed such as m_start = l or nL_start = 10, etc

Maxldx = 30; % 0 ~ 30 because of 31- length m-sequence

MatSetCSG = [];

N_d = l + M;

while ((nb start + M- (mod (N_d, M) -l) -l + N_d <MaxIdx) I (m_start + M- (mod (N_d, M) -D-l + N_d == MaxIdx)),

for ii = 0: M— (mod (N_d, M) -l) -l, MatSetCSG = [MatSetCSG; nb start + ii m_start + ii + N_d];

end% end of for, ii

N_d = N_d + l;

end% end of while

%% program end

Here, N_d = 9 is set to assign m_0 and m_l in a combination different from the cell ID already defined by the modular aspect.

For example, the cell group ID combination of (πιθ, ml) generated by the Matlab algorithm 3 is as follows.

MatSetCSG = [

09

1 10

2 11

3 12

4 13

5 14

6 15

7 16

0 10

1 11

2 12

3 13

n

One n

124

]

That is, it is proposed to add a total of 79 cell group IDs, and it is possible to further define a total of 237 cell IDs by combining with three PSCs. From the result, a desired number can be selected within the number of 79 cell group IDs and defined as the ID for the CSG cell. At this time, it is preferable to select the desired number in the order in which they are generated, but in the present embodiment, no constraint is placed thereon.

In this embodiment, m_start = 0 is assumed, but the present invention is not limited thereto. Therefore, in another embodiment according to the present invention, it is proposed to add the following combination as the case where m_start = l.

MatSetCSG = [

110

2 11

3 12

413

514

6 15

716

8 17

1 11

212

3 13

i

422 1 24

2 25

];

On the other hand, in the above-described case, considering both the swapping of SSC1 and SSC2, the Mat lab algorithm 3 can be changed as follows.

Mat lab algorithm 4

N— d is the distance between m „0 and m_l (distance between m_0 and m_l)

M: number of segl-based scrambling codes

%% program start

M = 8; % for this exam le

nb start = 0; % this value can be changed such as m_start = l or nL.start = 10, etc Maxldx = 30; % 0-30 because of 31— length m-sequence

MatSetCSG = [];

N_d = l + M;

whi le ((m_start + M- (mod (N_d, M) -l) -l + N_d <MaxIdx) I (m_start + M- (mod (N_d, M) -l) -l + N_d == MaxIdx)),

for i i = 0: M— (mod (N_d, M) -l) -2,% this part has been changed

MatSetCSG = [MatSetCSG; nb start + i i m— start + i i + N_d];

end% end of for, ii N_d = N_d + l;

end% end of whi le

%% program end

Accordingly, a total of 64 cell groups I, that is, a total of 192 cell IDs are reserved for CSG cells.

MatSetCSG = [

0 9

1 10

2 11

3 12

4 13

5 14

6 15

0 10

1 11

2 12

3 13

4 14

5 15

0 11

1 12

2 13

31

291 223

0 22

1 23

023

]

2) Method of increasing index number of PSS (Primary Synchronization Signal) Next, in another embodiment of the present invention, a PSC other than SSC is added.

A method of obtaining an ID for a CSG cell will be described.

As described above, in the current 3GPP LTE standard, the root index of the PSC is defined by the ZC root indexes 25, 29, and 34. These increments 29 and 340 = 63-29 satisfy the complex symmetry characteristics described above, It is possible to detect a signal through a single correlation operation.

Therefore, in this embodiment, it is proposed to define one tote index as a PSC index for the CSG cell, and to use the index as the CSG cell indicator. In particular, the root index has a complex symmetry relationship with the remaining root index of 25. It is proposed to use 38 (= 63-25) which satisfies. In other words, it is proposed to use the CSG cell or HeNB by selecting the root index to satisfy the root index and the root index symmetry except for the combination that already satisfies the root symmetry property.

For example, if the PSC is {26, 29, 34}, 37 (= 63-26) satisfying the complex symmetry relationship with 26 can be used as the HeNB index. In addition, the PSC currently regulated is {29, 34, When using the same ZC root index, ZC root index 260 = 63-37) may be used as the HeNB index.

This embodiment of defining an additional PSC such that the PSC satisfies the complex symmetry characteristic is described above.

It can be used in combination with embodiments that add SSC. That is, according to the present embodiment, since the same PSC is used between HeNBs, the PSC-based scrambling effect can be eliminated. That is, the above concept may be applied while defining an additional PSC index so that the ambiguity problem between adjacent cells disappears. In this case, PSC-based scrambling may be applied in consideration of interference between the macro cell and the CSG cell. For example, assuming that a PSC indicating a CSG cell (femtocell) is, the PSC-based scrambling code applied at this time may be defined by changing to Equation 18 or Equation 19 below.

(Equation 18) c ₀ (n) = c ((n + N ^) mod 3l)

c _x (n) = c ((n + + 4) mod31)

[Equation 19] _{c D (n) = c (} (n + 6) mod31)

c ₁ (n) = c ((n + 7) mod31)

On the other hand, the present embodiment proposes a method in which the division between the macro cell and the femtocell (HeNB cell, CSG) is indicated by the time relationship between the SSS and the PSS. Hereinafter, the method according to the present embodiment will be described in terms of securing a CSG cell indicator. In general, it may be extended and interpreted as a method of increasing the number of cell IDs. Briefly, the time relationship between the SSS and the PSS for the FDD (frame structure 1 of the 3GPP LTE system) is as described above with reference to FIGS. 1 and 2, and will be described in more detail in terms of the time relationship therebetween.

8 is a diagram illustrating a time relationship between an SSS and a PSS in a frame, and FIG. 9 is a diagram illustrating a method of transmitting additional information by changing a time position between an SSS and a PSS according to an embodiment of the present invention.

That is, as shown in FIG. 8, in the current 3GPP LTE system, the last OFDM symbol of the first slot in subframe 0 (symbol 6 in normal CP mode and extended CP mode) PSS at symbol 5) and SSS at the symbol immediately before it. Therefore, in the present embodiment, it is proposed to set the macro cell to indicate that the PSS is transmitted in the slot immediately after the SSS, similarly to the time relationship between the existing PSS and the SSS shown in FIG. In addition, as shown in FIG. 9, unlike the conventional case, it is assumed that the PSS indicates the CSG cell unlike the macro cell when the PSS is ahead of the SSS.

In this embodiment, it is proposed to indicate the CSG cell by the time positional relationship between the PSS and the SSS. That is, the SSS-PSS order may be set to indicate a macro cell, and the PSS-SSS order may indicate a CSG cell. In this case, the UE may distinguish each cell by performing a hypotheses test with respect to the time position where the SSS comes based on the PSS.

As a specific example of the time relationship shown in FIG. 9, in the normal CP mode, SSS is transmitted to symbol 5 of subframe 0 and slot 0 and PSS is transmitted to symbol 6 to indicate macro cell ID, and subframe 0 and slot 0 are shown. PSS for symbol 5 and SSS for symbol 6. It can be transmitted to indicate the CSG cell ID. In addition, in the extended CP mode, subframe 0, SSS in symbol 5 and SSC in symbol 5, and PSC in symbol 6 may be transmitted to indicate a macro cell ID, PSC in symbol 6 of subframe 0 and slot 0, and a symbol. In step 6, the SSS may be transmitted to indicate the CSG cell. According to this embodiment, the conventional 504 cell IDs may increase to 1008 in total.

For convenience, FIG. 8 depicts a cell other than the CSG cell, and FIG. 9 illustrates the CSG cell. However, the reverse is also applicable. That is, FIG. 8 may be set such that the CSG cell and FIG. 9 represent other cells than the CSG cell.

8 to 9, the PSS and the SSS need not be temporally adjacent OFDM symbols.

In summary, additional cell IDs can be defined by the relative timing interval or order of PSS and SSS, which can be used as HeNB (CSG, femto) cell ID indicators.

4) How to use scrambling code

On the other hand, the present embodiment proposes to use the cell ID previously defined as it is, but to distinguish the CSG cells by performing the segment 2 based scrambling for the synchronization signal transmitted in the CSG cell.

By doing this, if there is a UE that supports only the macro cell and a UE that supports both the macro cell and the CSG cell, it does not affect the UE that supports only the existing macro cell, and the UE supporting both will recognize the CSG cell indicator. There is a number. That is, the CSG cell can be indicated by the scrambling method.

According to the present embodiment, a method of performing segment 2 based scrambling It is as follows.

[Equation 20]

⁰⁾ («) c ₀ (ϊΐ) 2 ^ ^Ϋ («) in subframe 0

= [ ^MI («) ^ (in subirame 5

, 、 M in subirame 0

{nj in subframe 5 In addition, as another method according to the present embodiment, a PSC-based scrambling code may be defined as follows to indicate a CSG cell.

[Equation 21]

Ame 0

rame 5

_ 、 In subframe 0

in subframe 5 In addition, it is also possible to represent the CSG cell in the combination of the equation (20) and (21). That is, the CSG cell may be represented by defining two SSCs as follows. [Equation 22] in subframe O

in subframe 5

s} ^m ° (n) c _Q (n) in subframe 0

Q ^ (n) c _O (n) in subirame 5 The method of Equations 20 to 22 relates to a method of utilizing a previously defined scrambling code as it is. However, if you are prepared for the additional memory burden, It is also possible to define additional sequences and apply them in the same way.

For example, segment 2 based scrambling for CSG may be represented as follows.

[Equation 23] " ⁰ («) ¾ (n) zf ¹⁰ (n) in subframe 0

(2n) =

( ₀ (fi) ^ma) (H) in subframe 5 (ii) c _j (n) in subframe 0

(n) («) in suhframe 5

In this case, the segment 2 based scrambling sequence

It can be defined as follows.

[Equation 24] z ^ ^a)二 z (n + ( _Q mods +))] 10 (131)

zf ^l) (n-((¾H-(^ modS + n _off )) mod 31) where "^ is defined to be distinct from the previously defined scrambling code, and may be, for example — ⁸ .

Meanwhile, a case of separately generating a PSC-based scrambling code for CSG may be represented as follows.

[Equation 25] (n) c ₂ (n) in subframe 0

d (2n) =

¾ ⁾ (n) c ₂ (H) in subfram e 5 s ^ () c ₃ {) z [ ^m (n) in subframe 0

0 ⁾ («) * ¾ (w) in subframe 5 Here, the newly defined PSC-based scrambling code may be represented as follows.

(Equation 26) o ₂ (n) 二 c ((¾ + A ^) mod31) c3 (X) 二 ¾ ( ^¾ + ^N i'D + l) mod 31)

Herein, ^N ^ may be defined to be different from the existing scrambling code, and may be, for example, / ^{£) = 6} .

In this case, a method of increasing the number of cell IDs by SS swapping of the main synchronization signal and a method of using a PSS-based scrambling code may be used in combination. For convenience of description, a cell ID for a cell other than a CSG is maintained as it is, and a method of additionally defining a cell ID of a CSG cell, that is, an indication of a CSG cell will be described as an example.

For example, the form in which the main synchronization signal PSS is transmitted after the sub-synchronization signal SSS is transmitted (hereinafter, referred to as "SSS + PSS Form ¹ ") indicates a general cell, not a CGS cell, After the PSS) is transmitted, it is assumed that the form of the sub-synchronization signal (SSS) (hereinafter referred to as SS + SSS type) indicates a CSG cell. The above-described PSS-based scrambling code for indicating a general cell is defined as 6 up to cyclic shift indexes 0 to 5, and may be transmitted in the form of SSS + PSS. In addition, a method of defining six indexes from 6 to 11 as a cyclic shift index for indicating a CSG cell and transmitting them in the form of PSS + SSS can be used. In the method according to the present embodiment, the above-described cyclic shift index is exemplary only and is not necessarily limited to the above-described index.

On the other hand, as described above, the advantage of using a combination of the synchronization signal swapping method and the PSS-based scrambling code is as follows. Assume a two-cell scenario. As described above, the SSS + PSS type uses the same non-CSG cell, not the CSG cell, and the same assumption that the PSS + SSS type represents the CSG cell.

FIG. 10 illustrates a problem that may occur when only the synchronization signal swapping method is used.

In FIG. 10, it is assumed that cell A uses PSS0 and SSS0 and transmits in the form of SSS0 + PSS0. Also, it is assumed that cell B uses PSS1 and SSS1, and transmits the synchronization signal in the form of swapped sync signal, that is, in the form of PSS1 + SSS1 in contrast to cell A. In this case, the UE-side receiving end may be received as shown in FIG. 10 due to a timing difference from each cell. That is, when received as shown in FIG. 10, a false alarm combination may be better for PSS1 + SSS0 and SSS1 + PSS0.

However, as in the embodiment described above, swapping of the synchronization signal and indicating the CSG cell If an additional PSS-based scrambling code is defined and used, a false alarm problem as described above can be solved.

As mentioned above, this problem can be solved by defining and applying additional PSS-based scrambling for CSG cells according to the synchronization signal swapping (hereinafter, this method is referred to as "first option" of the present invention). It can also be seen that the signal swapping method is used in combination with the PSC-based scrambling method shown in Equation (25).

Meanwhile, another embodiment of the present invention proposes to apply the PSS scrambling code for the CSG cell in the form of Equation 21 without defining six more PSC-based scrambling codes as in the above-described embodiment. (Hereinafter, such a method is referred to as "second auction ¹ " of the present invention).

On the other hand, in some cases, when the same PSS-based scrambling code is used for the sub-synchronization signal (SSS), a delamination problem may occur.

FIG. 11 is a diagram for describing a problem of stratification that may occur when the same PSS-based scrambling code is used for an auxiliary sync signal.

That is, cell A transmits in the form of SSS0 + PSS0, and cell B transmits in the form of PSS0 + SSS0. However, when there is a timing difference between both cells, the SSS0 stratification problem may occur as shown in FIG. .

In a preferred embodiment of the present invention for solving such a problem, 8 segment 1 based scrambling defined in the prior art is applied to a general cell other than a CSG cell that transmits a synchronization signal in SSS + PSS form. For the CSG cell that transmits the synchronization signal in the form, it is additionally different from the normal cell that is not the CSG cell. We propose a method to further define and use the defined eight segment 1 based scrambling (hereinafter, this method will be referred to as "third junction" of the present invention). In this embodiment, the eight segment 1 based scrambling codes additionally defined may be defined in a form in which different circular movements are applied using a polynomial for generating a scrambling code that is conventionally defined and used. The above equation

It can be seen as a combination of 7 and (24).

On the other hand, another embodiment of the present invention proposes a method used by applying the combined form of Equation 23 and Equation 24, i.e., defining and using segment 2 based scrambling. The fourth option may be used to solve the problems described with reference to FIGS. 10 and / or 11. In addition, the first to fourth units described above may be independently used or in various ways. For example, the first junction may be used in combination with the third junction, that is, by additionally defining a segment 1 based scrambling in addition to a swapping scheme of a synchronization signal and PSC based scrambling. In addition, the first instruction may be used in combination with the fourth instruction, that is, a swapping method of a synchronization signal, and a PSC. In addition to the base scrambling, segment 2 based scrambling may be additionally defined and used.

In addition, the second and third suction units may be used in combination. That is, swapping of the synchronization signal, PSC-based scrambling and segment 1 based scrambling of the modified form as shown in Equation 21 may be additionally defined and used. Also said The second option may be used in combination with the fourth option. That is, a method of distinguishing using segment 2 based scrambling together with synchronization signal swapping and modified PSC commercial scrambling is also applicable.

In addition, the present invention does not exclude the various combinations of the above-mentioned instructions.

4) How to increase the number of cell IDs through phase modulation

On the other hand, in the present embodiment, as described above, a method of indicating an indicator indicating an ID of a CSG cell or the like through phase rotation of a synchronization signal is proposed. For example, in a macro-cell (referred to as a macro-cell in the description of the present invention for convenience and may be referred to as a non-CSG cell), it is determined by (mO, ml) for the 0th subframe. If the code combination is represented by (SSC1, SSC2), the indicators can be distinguished from the 0th subframe and the 5th subframe as follows. In the following description, the scrambling application is omitted for convenience of description.

* For macro cell: (SSCl, SSC2) in the 0th subframe, (SSC2,

SSC1)

* For CSG (or Repeater): 0 subframe (-SSC1, -SSC2), 5th subframe (-SSC2, -SSC1)

That is, each cell can be distinguished through phase modulation performed by using (1, 1) for the macro cell and (-1, -1) for the CSG.

As another example, it can be classified as follows.

* For macro-cell: (SSCl, SSC2) in the 0th subframe, (SSC2, SSC1)

* For CSG (or Repeater): (SSC1, -SSC2) in the 0th subframe, (SSC2, -SSC1) in the 5th subframe

That is, each cell can be distinguished through phase modulation performed by using (1, 1) for the macro cell and (1, -1) for the CSG.

As another example, it can be classified as follows.

* For macro-cell: (SSCl, SSC2) in the 0th subframe, (SSC2, SSC1) in the 5th subframe

* For CSG (or Repeater): 0 subframe (SSCl, -SSC2), 5th subframe (-SSC2, SSC1)

That is, it is possible to distinguish each cell through phase modulation performed by using (1, 1) for the macro cell and (-1, 1) for the CSG.

If it is necessary to indicate two or more indicators (for example, to display both the CSG cell and the repeater cell), it can be expressed as follows.

* For macro-cells: (SSCl, SSC2) in the 0th subframe, (SSC2,

SSC1)

* For CSG: (exp (j * 2 * pi * l / 3) * SSCl, exp (j * 2 * pi * l / 3) * SSC2) in the 0th subframe, (exp (j * 2 * pi * l / 3) * SSC2, exp (j * 2 * pi * l / 3) * SSCl)

* For repeater: (exp (j * 2 * pi * 2/3) * SSCl, exp (j * 2 * pi * 2/3) * SSC2) in the 0th subframe, (exp (j * 2 * pi * 2/3) * SSC2, exp (j * 2 * pi * 2/3) * SSCl)

Ho

* Macro—for cells: subframe 0 (SSCl, SSC2), subframe 5 (SSC2, SSC1)

* For CSG: (SSCl, exp (j * 2 * pi * l / 3) * SSC2) in the 0th subframe, (SSC2, exp (j * 2 * pi * l / 3) * SSCl in the 5th subframe )

* For repeater: (SSCl, exp (j * 2 * pi * 2/3) * SSC2) in the 0th subframe, (SSC2, exp (j * 2 * pi * 2/3) * SSCl in the 5th subframe )

Ho

* For macro cell: (SSCl, SSC2) in the 0th subframe, (SSC2, SSC1) in the 5th subframe

* For CSG: (SSCl, exp (j * 2 * pi * l / 3) * SSC2) in the 0th subframe, (exp (j * 2 * pi * l / 3) * SSC2, SSCl in the 5th subframe )

* For repeater: (SSCl, exp (j * 2 * pi * 2/3) * SSC2) in the 0th subframe, (exp (j * 2 * pi * 2/3) * SSC2, in the 5th subframe SSCl)

In summary, the present embodiment appreciates that additional information can be transmitted using phase modulation of the SSC, and proposes to represent a CSG cell using the phase modulation, and according to the amount of additional information, the BPSK and QPSK schemes are used. Phase modulation can be performed. In addition, even in the BPSK scheme, four pieces of information may be additionally transmitted according to a combination of phase modulation applied to SSC1 and SSC2.

The detailed description of the preferred embodiments of the invention disclosed as described above is provided to enable any person skilled in the art to make and practice the invention. Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed without departing from the spirit and scope of the invention described in the claims below. I can understand that will be. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Industrial Applicability

As described above, the method according to the disclosed embodiments may further allocate a physical layer ID to distinguish a CSG cell in a 3GPP LTE system, or reserve a part of an existing physical layer cell ID to utilize a CSG cell. Applicable to the scheme. However, the allocation of the physical cell ID for the additional target may be applied to various systems as well as the 3GPP LTE system, and the additional target may be a MBMS ID, a hot-spot indicator, as well as a target such as a relay of the IEEE system. And so on.

Claims

[Range of request]

[Claim 1]

In the method for transmitting physical layer cell ID information,

Transmitting a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), respectively;

And physical layer cell ID information in accordance with a temporal relationship between the transmission of the main synchronization signal and the transmission of the subsynchronization signal.

[Claim 2]

The method of claim 1,

The physical layer cell ID related information represents cell ID information of a serving cell and service attribute information of the serving cell.

The service attribute information indicates whether the serving cell is a CSG Closed Subscriber Group cell, a relay station cell, a multimedia broadcast multicast service (MBMS) indicator, or a hot spot indicator.

The cell ID information of the serving cell indicates all or part of the serving cell ID information.

[Claim 3]

The method of claim 1,

CSG (Closed) when transmitting the sub sync signal after the main sync signal

Subscriber Group) cell ID,

The CSG cell when the main sync signal is transmitted after the sub-sync signal is transmitted A physical layer cell ID information transmission method indicating a cell ID other than this.

[Claim 4]

In the method for transmitting physical layer sal ID information,

Performing scrambling according to any one of first type scrambling or second type scrambling to two secondary synchronization channel (S-SCH) signals according to a combination of a first segment and a second segment, respectively; And

Transmitting the scrambled two signals as two sub-sync codes (SSC),

The first type scrambling and the second type scrambling may be performed by the scrambling based on which segment of the first and second segments is performed, a combination of a main sync code based scrambling sequence multiplied by each sub sync code, and each sub sync. The scrambling method is distinguished by one or more morphologies of scrambling when multiplying the code.

And transmitting physical layer cell ID information according to whether one of the first type scrambling and the second type scrambling is applied in the scrambling step.

[Claim 5]

The method of claim 4, wherein

The information on the physical layer cell ID may include at least one of whether the serving cell is a closed subscriber group (CSG) cell, a relay station cell, a multimedia broadcast multicast service (MBMS) indicator, or a hot spot indicator. A method of transmitting physical layer cell ID information.

[Claim 6]

The method of claim 4,

When the second type scrambling is applied in the scrambling step, the two sub-synchronization codes transmitted indicate a CSG cell ID.

And when the first type scrambling is applied in the scrambling step, the two sub-sync codes transmitted indicate a cell ID other than the CSG cell.

[Claim 7]

The method of claim 6,

The first type scrambling is performed by applying scrambling to a second segment using a scrambling sequence based on the first segment,

The second type scrambling is performed by applying scrambling to the first segment using a scrambling sequence based on the second segment.

[Claim 8]

The method of claim 6,

The main sync code based scrambling sequence includes a first main sync code based scrambling sequence and a second main sync code based scrambling sequence, wherein the first type scrambling comprises a first sub sync channel of the two sub sync channel signals. And performing scrambling using the first main sync code based scrambling sequence on a signal and the second main sync code based scrambling sequence on a second sub sync channel signal. The second type scrambling is a scrambling using the second main synchronization code based scrambling sequence on the first sub-synchronization channel signal and the first main synchronization code based scrambling sequence on the second sub-synchronous channel signal. A method of transmitting physical layer cell ID information performed.

[Claim 9]

The method of claim 6,

The second type scrambling differs from the first type scrambling in at least one of a primary sync code based scrambling sequence used, the first segment based scrambling sequence and the second segment based scrambling sequence, a physical layer cell ID. Information transmission method.

[Claim 10]

In the method for transmitting physical layer cell ID information,

Performing phase modulation according to any one of different types of phase modulation preset in two sub-synchronization codes (SSCs); And

Transmitting the phase modulated two sub-sync codes,

The preset different types of phase modulation are distinguished according to different code values of length 2 multiplied by the two sub-sync codes,

And physical layer cell ID information in accordance with which of the preset different types of phase modulation are applied in the phase modulation step.

[Claim 11]

The method of claim 10, The preset different types of phase modulation include first type phase modulation and second type phase modulation,

The first type phase modulation and the second type phase modulation are different from each other in phase modulation of BPSK, QPSK, or M-PSK scheme phase modulation in the first and second codes constituting the two sub-synchronization codes. Is done by applying a different combination,

And a CSG cell when the first type phase modulation is applied and a cell other than the CSG cell when the second type phase modulation is applied.

[Claim 12]

The method of claim 10,

The preset different types of phase modulation include first type phase modulation, second type phase modulation, and third type phase information.

The first type phase modulation to the third type phase modulation are each other in a phase modulation of any one of a BPSK scheme, a QPSK scheme, or an M—PSK scheme phase modulation in a first code and a second code constituting the two sub-sync codes. Is performed by applying a different combination, and indicates a CSG cell when the first type phase modulation is applied, indicates a repeater cell when the second type phase modulation is applied, and the CSG when the third type phase modulation is applied. A method for transmitting physical layer cell ID information indicating a cell or a cell other than the relay cell.

[Claim 13]

Selecting a sequence having a root index of any one of the first to fourth root indices; And Transmitting the selected sequence as a main synchronization code (PSC), wherein any one of the first to fourth root indices is set to indicate specific cell ID related information in addition to the general cell ID;

The first to fourth root indices are divided into two pairs, a first pair and a second pair, and a sum of root indices belonging to the first and second pairs is generated as a sequence transmitted as the main sync code. A method of transmitting physical layer cell ID information based on length.

[Claim 14]

Selecting a sequence having a root index of any one of the first to third toot indexes; And

And transmitting the selected sequence as a main synchronization code (PSC), wherein any one of the first to third root indices is configured to indicate specific cell ID related information in addition to the general cell ID.

The sum of the root indexes except for the root index indicating specific cell ID related information other than the general cell ID among the first to third root indexes is based on the generation length of the sequence transmitted as the main sync code,

And a root index indicating the general cell ID related information does not depend on a generation length of a sequence in which a sum with any one of other root indexes is transmitted as the main sync code.

[Claim 15]

The method according to claim 13 or 14,

In addition to the general cell ID, specific cell ID related information may include cell ID information of the serving cell and the serving. Represents service attribute information of a cell.

The service attribute information indicates one or more of whether the serving cell is a CSGCClosed Subscriber Group (CSGCClosed Subscriber Group) cell, a relay station cell, a Multimedia Broadcast Multicast Service (MBMS) indicator, or a hot spot indicator.

Cell ID information of the serving cell indicates all or part of the serving cell ID information.

[Claim 16]

Selecting the first index (m ₀ ) and the second index (n) as combinations for distinguishing the cell group IDs; And

Transmitting two sequences of length M according to the selected first index and second index combination (m ₀ , tin) as two sub-sync codes,

When the selected (m ₀ , n) belongs to the first preset group, the two sub-synchronization codes indicate a Closed Subscriber Group (CSG) cell, and when the selected 0), n) belongs to the second preset group The two floating channel codes represent a cell that is not a CSG cell,

The first group includes at least two overlapping indexes between each index included in the combination of (m ₀ , mi) and (1, m ₀ ) among the possible combinations of two M-length sequence combinations, and _mo and _mi And a preselected combination of the number of combinations required to represent the CSG cell, starting from a combination satisfying a condition where the difference is minimal.

[Claim 17]

The first index m ₀ and the second index _mi as a combination for distinguishing the cell group IDs. Selecting; And

Transmitting two sequences of length M according to the selected first index and second index combination m ₀ , n as two sub-sync codes,

When the selected (m ₀ , ι) belongs to a preset first group, the two sub-synchronization codes indicate a CSGCClosed Subscriber Group cell, and when the selected (m ₀ , m) belongs to a preset second group, The two floater channel codes represent cells that are not CSG cells,

The first group is a combination of the first index and the second index (, nn) (0,1), (2,3),

(4,5), (6,7), (8,9), (10,11), (12,13), (14,15), (16,17), (18,19), (20 , 21), (22,23), (24,25), (26,27) and (28,29)

The second group is

PCT / KR2009 / 003270

Method for transmitting physical layer cell ID information comprising a combination of the first index and the second index combination (m ₀ , mi) other than the first group according to:

(Where is the cell group _ID) .