KR101995625B1 - Apparatus and method of communicating for detecting non-orthogonal preambles - Google Patents

Abstract

Wherein the base station comprises: a calculation unit for calculating a power delay profile (PDP) from the received signal using each of a plurality of root indices relating to random accesses; a calculation unit for calculating, from among the at least one peak A selector for selecting a first peak and a first preamble corresponding to the first peak, and for transmitting a first repetition signal from which the first preamble has been removed to the calculation unit, And a recovery unit for generating the recovery unit.

Description

[0001] APPARATUS AND METHOD FOR COMMUNICATION FOR DETECTING NON-ORTHOGONAL PREAMBLES [0002]

The present invention relates to a communication method between a terminal and a base station performing wireless communication, and more particularly to a communication method of detecting a non-orthogonal preamble in a random access (RA) process.

The rapid development of Information and Communications Technologies (ICT) is expected to be a Hyper-connected Society in the not-too-distant future. The second connection society is known as a society in which all objects including people, processes, data, and objects are connected by a network. The core constituent of this technology is Machine to Machine (M2M) or Internet Things.

In such a hyperconnected society, the number of independent devices (machines, communication equipment, terminals, etc.) that perform communications will increase exponentially. Therefore, in order for an extremely large number of independent devices to perform wireless connection, a radio access collision or radio resource shortage due to a radio resource request processing must be solved.

A conventional method of using a plurality of root sequences in a random access procedure can produce a larger number of preambles. However, in a random access procedure using two or more root sequences, there is a possibility that the orthogonality between the preambles is not maintained and the performance of the detector itself deteriorates. Particularly, there is a high possibility that a preamble that is not transmitted from a mobile station is erroneously detected in the base station. In this case, radio resources of the base station may be wasted. In addition, when the wireless resource waste of the base station is worsened, the random access success rate of the terminals is lowered, and consequently, connection time delay and power consumption loss of the terminals may occur.

Various aspects and embodiments of a communication method for performing a preamble recovery procedure on a non-orthogonal preamble transmitted from a plurality of terminals through a random access procedure and eliminating an interference signal using the recovered preambles are presented . More specifically, a new random access procedure may be performed in parallel with and / or in place of the previous random access scheme, and the devices may be able to use resources more efficiently in this process. Illustrative, but not limiting, aspects are described below.

According to an aspect of the present invention, a base station (eNodeB: E-UTRAN Node B, also known as Evolved Node B) that performs random access with a plurality of UEs (User Equipment) is provided. In the following description, the terminal includes a laptop computer, a mobile phone, a smart phone, a tablet PC, a mobile internet device (MID), a PDA (Personal Digital Assistant) such as a personal digital assistant (EDA), an enterprise digital assistant (EDA), a handheld console, an e-book, or a smart device. The base station may be implemented as a processor and may be implemented at least temporarily by the processor. Wherein the base station comprises: a calculation unit for calculating a power delay profile (PDP) from a received signal using each root index among a plurality of root indexes for a random access; A selector for selecting a first peak of at least one peak and a first preamble corresponding to the first peak and for transmitting the first repetition signal from which the first preamble has been removed to the calculation unit And a recovery section for causing a new power delay profile to be generated.

According to one embodiment, the selector may select the first peak having the largest one of the at least one peak exceeding the predetermined threshold within the power delay profile.

According to another embodiment, the selector selects a second peak among at least one peak exceeding a predetermined threshold from a newly generated power delay profile, and the recovery unit recovers a second preamble corresponding to the second peak can do. More specifically, the selector may select the second peak having the largest one of the at least one peak exceeding the predetermined threshold existing in the newly generated power delay profile.

According to another embodiment, when the power delay profile is repeatedly calculated, the selection unit may reduce the predetermined threshold based on the number of times of the iterative calculation.

According to another embodiment, the recovery unit may transmit a second repetition signal from which the second preamble is removed in the first repetition signal to the calculation unit to generate a new power delay profile.

According to another embodiment, in the case where there is no peak exceeding a predetermined threshold within the power delay profile, the selection unit may terminate preamble detection on the root index corresponding to the power delay profile.

According to another embodiment, the recovery unit obtains a preamble index, a measured channel coefficient, and a delay coefficient corresponding to the first peak from the power delay profile, and outputs the obtained preamble index, the channel coefficient, To recover the first preamble.

According to another aspect, a preamble recovery method is provided. The method comprising: selecting a first one of at least one peak that exceeds a predetermined threshold within the power delay profile computed using each of a plurality of root indices; determining a first preamble corresponding to the first peak, Generating a new power delay profile corresponding to the first repeated signal from which the first preamble has been removed from the received signal and determining whether to continue with preamble recovery using the new power delay profile . ≪ / RTI >

According to one embodiment, the step of determining whether to continue with preamble recovery using the new power delay profile comprises the steps of: if there is a peak in the new power delay profile that exceeds the threshold, And determining to continue the preamble recovery.

According to another embodiment, the step of determining whether to continue with preamble recovery using the new power delay profile further comprises: if there is no peak exceeding the threshold in the new power delay profile, And to end the preamble recovery corresponding to the preamble.

According to another embodiment, the step of selecting the first peak may comprise selecting the first peak that is the largest value of at least one peak that exceeds the threshold within the power delay profile .

1 is an exemplary diagram illustrating a random access procedure between a plurality of terminals and a base station according to an exemplary embodiment of the present invention.
2A is a block diagram illustrating an operation of a preamble recovery apparatus according to an embodiment.
FIG. 2B is a block diagram illustrating the operation of the preamble detection apparatus according to an embodiment.
3 is a block diagram illustrating a base station according to one embodiment.
4 is a flowchart illustrating a preamble recovery method according to an embodiment.
5A to 5C are diagrams illustrating a power delay profile of a received signal according to the preamble recovery method.

Specific structural or functional descriptions of embodiments are set forth for illustration purposes only and may be embodied with various changes and modifications. Accordingly, the embodiments are not intended to be limited to the particular forms disclosed, and the scope of the present disclosure includes changes, equivalents, or alternatives included in the technical idea.

The terms first or second, etc. may be used to describe various elements, but such terms should be interpreted solely for the purpose of distinguishing one element from another. For example, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

It is to be understood that when an element is referred to as being "connected" to another element, it may be directly connected or connected to the other element, although other elements may be present in between.

The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises ", or" having ", and the like, are used to specify one or more of the features, numbers, steps, operations, elements, But do not preclude the presence or addition of steps, operations, elements, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention with reference to the accompanying drawings, the same components are denoted by the same reference numerals regardless of the reference numerals, and a duplicate description thereof will be omitted.

1 is an exemplary diagram illustrating a random access procedure between a plurality of terminals and a base station according to an exemplary embodiment of the present invention. Referring to FIG. 1, a plurality of terminal groups 121, 122, 123 and a base station 110 performing random access are shown. Illustratively, within one cell network radius, the base station 110 may be implemented such that a random access is performed using a predetermined number of root indexes. There may be a case where the predetermined number of root indexes is K. [ In this case, the N _M terminals included in the cell network may select any one of the K root indexes, generate a preamble using the root sequence corresponding to the selected root index, and transmit the preamble to the base station.

A plurality of terminals may be grouped into at least one group according to a root index used for preamble transmission. Illustratively, when K root indices are used in the cell network, the first terminal group 121 using the first root index r ₁ , the second terminal group 122 using the second root index r ₂ , The K terminal groups 123 up to the K terminal group 123 using the Kth root index r _K can be separated from each other.

Each terminal group can transmit a preamble using a root sequence having a cross correlation. However, when two or more root indexes are used, the cross-correlation property of Zadoff-Chu sequences will deteriorate and interference between the preambles generated using different root indices will be interfered with each other. Hereinafter, a detailed description of the operation of the base station for recovering each preamble using the power delay profile will be described.

로 정의될 수 있다. 이 경우에, 상기 셀 네트워크 내에서 임의접속을 수행하는 전체 단말의 개수 N_M은 아래의 수학식 1과 같이 계산될 수 있다.in case k represents an arbitrary integer of 1 or greater than K, the k-th root index number of UEs using the r _k is

. ≪ / RTI > In this case, the number N _M of all terminals performing random access in the cell network can be calculated by Equation 1 below.

In one embodiment, the Zadoff-Chu sequence used by the first terminal group 121 using the first root index r ₁ to generate a preamble can be summarized as Equation 2 below.

In Equation (2), N _ZC represents the length of the Zadoff Chu sequence, and n represents any integer equal to or greater than 0 and equal to or less than N _ZC -1. In Equation (2), the Zadoff Chu sequence corresponding to the first root index r ₁ is provided, but the mathematical expression for the Zadoff Chu sequence corresponding to each of the second root index r ₂ to the K root index r _K is given by the ordinary descriptor I will skip it because it is straight forward.

Each of the terminals described in this embodiment can perform open loop power control such that the signal-to-noise ratio (SNR) ρ received at the base station 110 is the same. The signal-to-noise ratio (SNR) ρ can be defined by Equation (3) below.

In Equation (3), P represents the power of the signal received at the base station, and N ₀ represents the power of the noise signal.

A signal y [n] received from each terminal through a physical random access channel (PRACH) to perform random access by the base station 110 can be calculated by Equation (4) below.

는 컨볼루션(convolution)을 나타내고,

는 제k 루트 인덱스 r_k를 이용하는 복수의 단말들 사이에서 제i 단말의 다중 경로 레일리 페이딩 채널 계수(Rayleigh fading channel coefficient)를 나타내고,

는 제k 루트 인덱스 r_k를 이용하는 복수의 단말들 사이에서 제i 단말이 전송한 프리앰블 시퀀스를 나타낼 수 있다. 또한, 상기 수학식 4에서 w[n]은 평균값이 0이고, 분산이 N₀인 백색 잡음(additive white Gaussian noise)을 나타낼 수 있다. 제k 루트 인덱스 r_k를 이용하는 제i 단말의 프리앰블 시퀀스

는 아래의 수학식 5와 같이 계산될 수 있다.In Equation (4), n represents an integer of 0 or more and N _ZC -1 or less,

Represents a convolution,

Represents the Rayleigh fading channel coefficient of the i < th > terminal among a plurality of terminals using the kth root index r _k ,

It may represent the k-th root index r preamble sequence a i-th terminal is transferred between the plurality of terminals using a _k. In Equation (4), w [n] may represent an additive white Gaussian noise with an average value of 0 and a variance of N ₀ . The k-th root index of the first preamble sequence using a terminal i r _k

Can be calculated as shown in Equation (5) below.

는 제i 단말에 의해 선택된 프리앰블 인덱스를 나타내고, N_CS는 순환 이동의 크기를 나타낼 수 있다. 이하에서는, 복수의 프리앰블 시퀀스를 포함하는 신호를 수신한 기지국이(110) 전력 지연 프로파일(PDP: Power Delay Profile)을 반복적으로 생성하여 적어도 하나의 프리앰블을 복구해나가는 과정에 관한 자세한 설명이 기재된다.In Equation (5)

Represents the preamble index selected by the i < th > terminal, and N _CS may represent the magnitude of the cyclic shift. Hereinafter, a detailed description will be given of a process of repeatedly generating a (110) power delay profile (PDP) and recovering at least one preamble by a base station receiving a signal including a plurality of preamble sequences .

2A is a block diagram illustrating an operation of a preamble recovery apparatus according to an embodiment. The base station described in this embodiment may include a preamble recovery apparatus and a preamble detection apparatus. FIG. 2A is a block diagram illustrating the operation of the preamble recovery apparatus included in the base station.

The preamble recovery apparatus may perform a decorrelation process on each root index using a signal received from a plurality of terminals. Illustratively, the preamble recovery device may perform the de-correlation process 210 for the first root index r ₁ . More specifically, the preamble recovery apparatus can be calculated as a first root index r power delay profile PDP [α] in the _first and the equation (6) below.

는 기지국이 수신한 수신 신호 y[n], 기준 자도프 추 시퀀스 z_r1[n] 및 시간 지연 α에 관한 이산 주기 상관 함수(discrete periodic correlation function)를 나타낼 수 있다. 또한, *는 지정된 신호에 관한 켤레 복소수(complex conjugation) 신호를 나타낼 수 있다. 프리앰블 복구 장치는 제1 루트 인덱스 r₁에 관한 비상관화(210) 과정을 통해 수신 신호 y[n]로부터 프리앰블 인덱스를 포함하는 원하는 신호를 추출할 수 있다.In Equation (6) _{,? Represents} an integer of 0 or more and N _ZC -1 or less,

May represent a discrete periodic correlation function with respect to the received signal y [n] received by the base station, the reference daughter dopchoice sequence _zr1 [n], and the time delay [alpha]. In addition, * may represent a complex conjugation signal for the specified signal. The preamble recovery apparatus can extract a desired signal including the preamble index from the received signal y [n] through the de-correlation process 210 with respect to the first root index r ₁ .

More specifically, in the de-correlation process for the j-th root index r _j for an arbitrary integer j equal to or greater than 1 and equal to or less than K, the base station can calculate the received signal y [n]

와 간섭 신호(interference signal)인

로 분리될 수 있다. 이 경우에, 수신 신호 y[n]에 포함되는 N_M 개의 프리앰블은 제j 루트 인덱스 r_j에 대응하는

개의 프리앰블과 상기 제j 루트 인덱스 r_j에 대응하는 프리앰블들과 비직교하는(non-orthogonal)

개의 프리앰블을 포함할 수 있다.The received signal y [n] is the desired signal

And an interference signal

. ≪ / RTI > In this case, the N _M preambles included in the received signal y [n] correspond to the _j- th root index r _j

Preamble and the j-th root preamble and non-(non-orthogonal) perpendicular corresponding to the index _j r

≪ / RTI >

As the number of root sequences used in the cell network increases, the preambles generated through the multi-root sequence may degrade the cross-correlation properties with each other. As a result, the size of the cross-correlation value can be increased. The base station of the present embodiment can expect the effect of increasing the preamble detection performance by reusing the previous preamble detection result. More specifically, the preamble recovery apparatus included in the base station can reconstruct each preamble using a channel profile included in the power delay profile. Also, the preamble recovery apparatus included in the base station can remove the interference signal using the preamble recovered from the original received signal, and can more efficiently detect the preamble using the received signal from which the interference is removed.

보다 크게 설정될 필요성이 존재한다.

가 복소 가우시안(complex Gaussian)으로서 CN(0,2α²/N_ZC)의 분포를 따르기 때문에

는 아래의 수학식 8과 같은 누적분포함수(CDF: Cumulative Distribution Function)에 기초하여 레일리 분포를 따르게 될 것이다.In addition, the preamble recovery device may first route the first set threshold value γ ₁ to calculate the power delay profile according to the index r _1, and detects the preamble using the power delay profile (220). It will be obvious to a person skilled in the art that, as shown in FIG. 2A, the preamble recovery apparatus can set each of the k-th thresholds? _K at the first threshold? ₁ according to each root index. The first threshold value γ ₁ relates to a noise signal

There is a need to be set larger.

Because it follows the distribution of CN (0,2α ² / N _ZC ) as a complex Gaussian

Will follow the Rayleigh distribution based on the Cumulative Distribution Function (CDF) as shown in Equation 8 below.

가 기설정된 임계치 γ보다 큰 경우로서 계산할 수 있다. 일실시예로서, 프리앰블 복구 장치는 잘못된 프리앰블이 복원될 확률 p_fr인 0.1%에 대응하는 제1 임계치 γ₁를 -9.737dB로서 상기 수학식 8에 따라 계산해낼 수 있다. 다른 일실시예로서, 프리앰블 복구 장치는 잘못된 프리앰블이 복원될 확률 p_fr인 0.01%에 대응하는 제2 임계치 γ₂를 -9.264dB로서 상기 수학식 8에 따라 계산해낼 수 있다. 앞서 기재된 잘못된 프리앰블이 복원될 확률에 관한 구체적 예시는 이해를 돕기 위한 설명일 뿐, 다른 실시예들의 범위를 제한하거나 한정하는 것으로 해석되어서는 안될 것이다.More specifically, the preamble recovery apparatus calculates the probability p _fr that the erroneous preamble is recovered

Is larger than a preset threshold value?. In one embodiment, the preamble recovery apparatus may calculate the first threshold value? ₁ corresponding to 0.1%, which is the probability p _fr , of the erroneous preamble to be -9.737 dB, according to Equation (8). In another embodiment, the preamble recovery apparatus may calculate the second threshold value? ₂ corresponding to 0.01%, which is the probability p _fr for recovering the erroneous preamble, to -9.264 dB according to Equation (8). The concrete example of the probability that the erroneous preamble described above is restored is only an explanation for understanding, and should not be construed as limiting or limiting the scope of other embodiments.

Also, the preamble recovery apparatus may recover the preamble and determine 230 whether to repeat the preamble recovery procedure. More specifically, the preamble recovery device may select a first one of the at least one peak that exceeds a predetermined threshold within the power delay profile for the jth root index r _j . In the case where K root indices are used in the cell network, j may represent any integer greater than or equal to 1 and less than or equal to K. [ More specifically, the first peak may indicate a peak having the largest value of at least one peak that exceeds the predetermined threshold within the power delay profile.

The preamble recovery apparatus may recover the first preamble corresponding to the first peak using the selected first peak. More specifically, the preamble recovery apparatus can determine the transmitted preamble index using the position number in the power delay profile corresponding to the first peak. Also, the preamble recovery apparatus can measure the channel coefficient from the power delay profile and calculate the delay coefficient. More specifically, the preamble recovery apparatus can recover the first preamble using Equation (9) using the selected first peak.

는 검출된 프리앰블 인덱스를 나타내고,

는 측정된 채널 계수를 나타내고,

는 전력 지연 프로파일로부터 계산된 지연 계수를 나타낼 수 있다.In Equation (9)

Denotes a detected preamble index,

Represents the measured channel coefficient,

May represent the delay coefficient calculated from the power delay profile.

The base station may determine in step 230 whether to repeat the preamble recovery procedure. More specifically, the preamble recovery apparatus included in the base station can generate the first repetition signal y ¹ [n] from which the first preamble recovered from the received signal is removed. The generated first repetition signal y ¹ [n] can be calculated by Equation (10) below.

In Equation (10), y ⁰ [n] may represent a signal y [n] received by the base station in the random access procedure. x ¹ [n] may represent a first preamble recovered by the base station using a first peak.

The preamble recovery apparatus can calculate a new power delay profile using the generated first repetition signal y ¹ [n]. Also, the preamble recovery apparatus may determine whether to repeat the preamble recovery process according to whether a peak exceeding the threshold value exists in the new power delay profile. A more detailed description of a configuration for determining whether to repeat the preamble restoration process will be described below with reference to the accompanying drawings.

In one embodiment, when the preamble recovery apparatus repeats the recovery of the preamble for m times, the m-th iteration signal generated by the preamble recovery apparatus may be calculated by Equation (11) below.

In Equation (11), m represents an integer equal to or greater than 1, and y ⁽⁰⁾ [n] may represent a received signal y [n]. Further, the preamble recovery apparatus can accumulate the recovered preamble in s _rj [n]. If k preambles corresponding to the _j- th root index r _j are recovered during the m-times repetition of the restoration process, the recovered preambles may be stored in the base station as shown in Equation (12) below.

FIG. 2B is a block diagram illustrating the operation of the preamble detection apparatus according to an embodiment. The preamble detection apparatus may remove (250) interference from the received signal using previously recovered preambles. More specifically, the preamble detecting apparatus may remove, as an interference signal, preambles for remaining root indexes other than the jth root index, when decorrelation on the jth root index is performed. For example, if K root indexes are used in the cell network, the preamble detection apparatus may combine the respective preambles corresponding to the remaining root indices r ₂ to r _K for de-correlation with respect to the first root index r ₁ , As shown in FIG. Through the above process, it is possible to expect the effect of improving the detection accuracy of the preamble by removing the preamble signals associated with the remaining root indices irrelevant to the de-correlation, as an interference signal.

는 아래의 수학식 13과 같이 계산될 수 있다.A signal in which the interference signal is removed by the preamble detection apparatus

Can be calculated as shown in the following equation (13).

The preamble detection apparatus can detect the preamble by performing the de-correlation (260) and the threshold setting (270) for each root index. In the process of the de-correlation (260) and the threshold value setting (270), the description described above with reference to FIG. 2A can be applied as it is, and a duplicate description will be omitted.

3 is a block diagram illustrating a base station according to one embodiment. 3, the base station 300 that performs random access with a plurality of terminals may include a calculation unit 310, a selection unit 320, and a restoration unit 330. The calculation unit 310 may calculate the power delay profile from the received signal using each of the plurality of root indexes related to the random access. In one embodiment, when K root indices are used in the cell network in which the base station 300 is included, the calculation unit 310 may calculate K power delay profiles corresponding to each of the K root indices.

The selector 320 may select the first one of the at least one peak that exceeds the predetermined threshold within the power delay profile. In one embodiment, the selector 320 may select, as the first peak, a peak having the largest one of the at least one peak present in the power delay profile.

The recovery unit 330 may recover the first preamble corresponding to the first peak. More specifically, the restoring unit 330 can determine the preamble index using the position number corresponding to the first peak in the power delay profile corresponding to the first root index. In addition, the recovery unit 330 may obtain the channel coefficient and the delay coefficient measured from the power delay profile using the position number corresponding to the first peak. The restoring unit 330 may recover the first preamble using the preamble index, the channel coefficient, and the delay coefficient.

The restoring unit 330 generates a first repetition signal from which the first preamble recovered from the received signal received by the base station 300 is removed, and transmits the first repetition signal to the calculating unit 310, So that a power delay profile can be generated.

In one embodiment, the selector 320 selects a second one of the at least one peak exceeding a predetermined threshold from the newly generated power delay profile, and the restoring unit 330 restores the second peak, 2 preamble can be repeated. The selecting unit 320 and the restoring unit 330 may repeat the process of recovering a specific preamble in the received signal according to predetermined conditions. As in the case of the first peak described above, the selector 320 can select the second peak as the peak having the largest value among the at least one peak existing in the newly generated power delay profile.

In another embodiment, the selector 330 may reduce the predetermined threshold based on the number of iterations when the power delay profile is iteratively calculated. As another embodiment, the selector 330 may reduce a threshold for detecting a peak according to the number of preambles recovered by the base station 300 in advance.

The recovery unit 330 generates a second repetition signal in which the second preamble is removed from the first repetition signal, and transmits the generated second repetition signal to the calculation unit 310 to generate a new power delay profile Can be regenerated. The configuration for determining whether the power delay profile is repeatedly generated and whether the process of repeating the recovery of the preamble continues or not will be described in more detail in Fig.

4 is a flowchart illustrating a preamble recovery method according to an embodiment. Referring to FIG. 4, a preamble recovery method 400 includes selecting 410 a first one of at least one peak that exceeds a predetermined threshold within the power delay profile calculated using each of a plurality of root indices, (420) a first preamble corresponding to the first peak, generating (430) a new power delay profile corresponding to the first repeated signal from which the first preamble has been removed from the received signal, And determining (440) whether to continue the preamble recovery using the power delay profile.

In the description of steps 410, 420 and 430, descriptions of the calculation unit 310, the selection unit 320, and the restoration unit 330 described in FIG. 3 are applied as they are And redundant description will be omitted.

In step 440, the base station may determine whether to continue the preamble recovery using the new power delay profile. Illustratively, if there is a peak in the new power delay profile that exceeds the threshold, the base station may continue to recover the preamble corresponding to the peak.

In another embodiment, the base station may determine to terminate the preamble recovery corresponding to the received signal if there is no peak in the new power delay profile exceeding the threshold.

The base station of the present embodiment can expect the effect of minimizing the interference effect generated by using the multi-root index in a manner that the preamble exceeding the specified threshold is recovered in advance and the recovered preamble is removed and the preamble is detected.

는 1 개이고, 제2 루트 인덱스 r₂를 이용하는 단말의 개수

는 2 개이고, 제3 루트 인덱스 r₃를 이용하는 단말의 개수

가 4 개이고, 기지국에서의 지정된 신호 대 잡음비 ρ가 10dB로 설정되고, 피크를 검출하기 위한 임계치 γ가 -9.5dB로 설정된 경우에 대해서 설명된다.5A to 5C are diagrams illustrating a power delay profile of a received signal according to the preamble recovery method. Referring to FIGS. 5A to 5C, a power delay profile graph according to a conventional preamble detection method 520 and a preamble detection method 510 using the preamble recovery according to the present embodiment is shown. In the present embodiment, three root sequences (K = 3) are used in the cell network, and the number of terminals using the first root index r ₁

And the number of terminals using the second root index r ₂

And the number of terminals using the third root index r ₃

Is set to 10 dB, and the threshold value? For detecting the peak is set to -9.5 dB.

Figure 5a is a first root index, the first power delay profile Y1 calculated by using the r ₁ being shown, Figure 5b is a second root index r ₂ of the second power delay profile Y2 calculated using is shown, Figure 5c is the third root index r ₃ of the third power delay profile calculated by the Y3 is shown. In this embodiment, N _ZC is 839 and N _CS is 13. In the conventional preamble detection method 520, the preamble sequences associated with different root indices are applied as interference signals, indicating that the cross-correlation property in the power delay profile is not ideal. On the other hand, the preamble detection method 510 according to the present embodiment can recover the preamble sequences related to each root index in advance using the peak value. Also, the preamble that has been restored can be processed as an interference signal in the process of generating the power delay profile related to another root index and removed. Accordingly, the preamble detection method 510 according to the present embodiment ideally shows cross correlation for each root index.

The embodiments described above may be implemented in hardware components, software components, and / or a combination of hardware components and software components. For example, the devices, methods, and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, such as an array, a programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing unit may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device , Or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer readable medium may include program instructions, data files, data structures, and the like, alone or in combination. Program instructions to be recorded on a computer-readable medium may be those specially designed and constructed for an embodiment or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

Although the embodiments have been described with reference to the drawings, various technical modifications and variations may be applied to those skilled in the art. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Claims (12)

Implemented by the processor:
A calculation unit for calculating a power delay profile (PDP) from a received signal using each root index among a plurality of root indexes related to random access;
A selector for selecting a first one of the at least one peak exceeding a predetermined threshold within the power delay profile; And
A recovery unit for recovering a first preamble corresponding to the first peak and transmitting a first repetition signal from which the first preamble is removed from the received signal to the calculation unit to generate a new power delay profile;
Lt; / RTI >
Wherein the selector selects a second one of the at least one peak exceeding a predetermined threshold from a newly generated power delay profile and the recovery unit recovers a second preamble corresponding to the second peak,
And wherein the selector reduces the predetermined threshold based on the number of iterations when the power delay profile is iteratively calculated.
The method according to claim 1,
Wherein the selector selects the first peak having the largest value among at least one peak exceeding the predetermined threshold within the power delay profile.
delete The method according to claim 1,
Wherein the selector selects the second peak that is within the newly generated power delay profile and has the largest one of the at least one peak that exceeds the predetermined threshold.
delete The method according to claim 1,
Wherein the recovery unit transmits a second repetition signal from which the second preamble is removed in the first repetition signal to the calculation unit to generate a new power delay profile. The method according to claim 1,
And wherein the selector terminates the preamble detection on the root index corresponding to the power delay profile when there is no peak in the power delay profile exceeding a predetermined threshold.
The method according to claim 1,
Wherein the recovery unit obtains a preamble index, a measured channel coefficient, and a delay coefficient corresponding to the first peak from the power delay profile, and calculates the first preamble using the obtained preamble index, the channel coefficient, Base station to recover.
Selecting a first one of at least one peak that exceeds a predetermined threshold within a power delay profile calculated using each of a plurality of root indices;
Recovering a first preamble corresponding to the first peak;
Generating a new power delay profile corresponding to a first repetition signal from which the first preamble has been removed from a received signal; And
Determining whether to continue the preamble recovery using the new power delay profile
Lt; / RTI >
Wherein determining whether to continue with preamble recovery using the new power delay profile comprises:
Determining to continue the preamble recovery corresponding to the peak if there is a peak in the new power delay profile that exceeds the threshold
/ RTI >
delete 10. The method of claim 9,
Wherein determining whether to continue with preamble recovery using the new power delay profile comprises:
Determining to terminate the preamble recovery corresponding to the received signal if there is no peak in the new power delay profile that exceeds the threshold
/ RTI >
10. The method of claim 9,
Wherein the step of selecting the first peak comprises:
Selecting the first peak within the power delay profile that is the largest of the at least one peak that exceeds the threshold
/ RTI >

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