CN101534539A

CN101534539A - Method and device for quickly searching cells

Info

Publication number: CN101534539A
Application number: CN200810065540A
Authority: CN
Inventors: 孙铭扬; 顾雪芹
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2008-03-11
Filing date: 2008-03-11
Publication date: 2009-09-16

Abstract

The invention discloses a fast cell search method, comprising: constructing a basic sequence based on a sequence category index; mapping the sequence index to a base station identifier; performing discrete Fourier transform (DFT) or inverse discrete Fourier transform (IDFT) on the basic sequence, and transforming The sequence of is sent as the reference sequence. The receiving end quickly completes the cell search by receiving and processing the reference sequence. The embodiment of the invention also discloses a transmitter device and a receiver device for fast cell search. The cell search method is simple, does not increase the complexity of the system, and is beneficial to fast cell detection, cell switching, and the like.

Description

A fast cell search method and device

技术领域 technical field

本发明涉及无线通信领域，具体涉及一种小区快速搜索方法及装置。The invention relates to the field of wireless communication, in particular to a cell fast search method and device.

背景技术 Background technique

在移动蜂窝网络中，地理覆盖区域被分成许多小区，每个小区由基站(BS)服务。每个小区还可以被进一步分成许多扇区。当移动站(MS)被加电时，它需要搜索BS以进行注册。而且，当MS发现来自当前小区的信号变弱时，它应准备到其它小区/扇区。由于这一点，要求MS搜索良好的BS以进行通信，其中候选列表由当前服务小区提供。快速识别BS以进行初始注册或切换的能力对于减小复杂性和降低功率消耗来说是重要的。In mobile cellular networks, the geographic coverage area is divided into cells, each cell served by a base station (BS). Each cell can be further divided into a number of sectors. When a mobile station (MS) is powered on, it needs to search for a BS to register. Also, when the MS finds that the signal from the current cell becomes weak, it should prepare to other cells/sectors. Due to this, the MS is required to search for a good BS to communicate with, where the candidate list is provided by the current serving cell. The ability to quickly identify BSs for initial registration or handover is important to reduce complexity and power consumption.

可以周期性发射小区特定参考信号(或同步信号)来执行小区搜索功能，通过试图检测每个参考信号进行穷尽搜索，并且随后确定最佳BS。由于移动站将接收来自其它扇区或小区发送的信号，因此，确定小区或扇区的参考信号时，参考信号之间的良好互相关性是重要的。与自相关性类似，两个序列之间的互相关性是对应于不同相对移位的序列自身。更精确地，在移位d处的互相关性被定义为：在一个序列与另一个序列的逐个元素相乘之后在全部项上求和的结果，该另一序列是相对于第一个序列共轭的并且移位了d项。A cell-specific reference signal (or synchronization signal) may be periodically transmitted to perform a cell search function, perform an exhaustive search by attempting to detect each reference signal, and then determine the best BS. Since the mobile station will receive signals transmitted from other sectors or cells, good cross-correlation between reference signals is important when determining reference signals for a cell or sector. Similar to autocorrelation, cross-correlation between two sequences is the sequences themselves corresponding to different relative shifts. More precisely, cross-correlation at shift d is defined as: the result of summing over all terms after element-wise multiplication of one sequence with another sequence with respect to the first sequence conjugated and shifted by the d term.

正交频分复用(Orthogonal Frequency Division Multiplexing，简称“OFDM”)是一种多载波调制(Multi-Carrier Modulation，简称“MCM”)，它采用多个载波，将要传送的数据流分解成多个低速的比特流，用这些低速的比特流分别去调制多个载波。即便是频谱相互混叠也能保持相互正交的波形。这样就避免了信号波形之间的干扰，同时还提高了频谱利用率。在OFDM系统中，输出为N个独立调制载波的输出之和。当这些载波加在一起时，可能出现一个很高的峰值。这将导致一个很高的功率峰均比(Peak Average Power Ratio，简称“PAPR”)问题。在使用DFT实现的OFDM系统中，一个OFDM符号s(n)，n＝0，1，...，N-1，的PAPR以分贝为单位的计算公式如下：Orthogonal Frequency Division Multiplexing ("OFDM") is a multi-carrier modulation (Multi-Carrier Modulation, "MCM"), which uses multiple carriers to decompose the data stream to be transmitted into multiple Low-speed bit streams are used to modulate multiple carriers respectively. The mutually orthogonal waveforms are maintained even if the frequency spectrums alias with each other. In this way, the interference between signal waveforms is avoided, and the spectrum utilization rate is also improved. In an OFDM system, the output is the sum of the outputs of N independently modulated carriers. When these carriers are added together, a very high peak may appear. This will lead to a high peak-to-average power ratio (Peak Average Power Ratio, referred to as "PAPR") problem. In an OFDM system implemented using DFT, the formula for calculating the PAPR of an OFDM symbol s(n), n=0, 1, ..., N-1 in decibels is as follows:

$PAPR PAPR = = 1010 log log [[\underset{k k &Element; &Element; [[00,, DN DN - - 11]]}{max max} \frac{{| | (({Σ Σ}_{n no = = 00}^{DN DN - - 11} s the s' ' ((n no)) exp exp [[- - j j 22 πnk πnk / / ((DN DN))]])) | |}^{22}}{\frac{11}{DN DN} {Σ Σ}_{k k = = 00}^{DN DN - - 11} {| | (({Σ Σ}_{n no = = 00}^{DN DN - - 11} s the s' ' ((n no)) exp exp [[- - j j 22 πnk πnk / / ((DN DN))]])) | |}^{22}}]]$

其中，DN是DFT的大小，D是过采样因子。参考信号的低PAPR性质使得参考信道电路发射具有高于数据功率的参考信号，以便于改善其它通信单元接收的参考信号上的信噪比/信干比，由此提供改善的信道估计、同步等。而如果参考信号的PAPR值很高，则需要发射机的功放以低能效操作在一个很大的线性区域并需要D/A(数/模)转换器和A/D(模/数)转换器具有很大的动态范围，从而提高系统实现的开销，并因此成为OFDM的主要缺点。当前导(Preamble)序列的PAPR值高于功放的线性范围，信号会被削波(限幅削波)。造成的失真将导致信道估计或者同步的不准确，并导致系统性能的劣化。Among them, DN is the size of DFT, and D is the oversampling factor. The low PAPR nature of the reference signal enables the reference channel circuit to transmit the reference signal at a higher power than the data in order to improve the signal-to-noise/signal-to-interference ratio on the reference signal received by other communication units, thereby providing improved channel estimation, synchronization, etc. . And if the PAPR value of the reference signal is high, the power amplifier of the transmitter is required to operate in a large linear region with low energy efficiency and requires a D/A (digital/analog) converter and an A/D (analog/digital) converter It has a large dynamic range, which increases the overhead of system implementation, and thus becomes the main disadvantage of OFDM. When the PAPR value of the preamble sequence is higher than the linear range of the power amplifier, the signal will be clipped (limited clipping). The resulting distortion will lead to inaccurate channel estimation or synchronization, and lead to degradation of system performance.

在现有协议里面，具有低峰均功率比的序列用作前导(Preamble)以做同步及信道估计之功能。其中一种比较常用的Preamble序列是二元PN序列。IEEE802.16e标准里所用的就是二元PN序列，其PAPR值达到4dB以上。In existing protocols, a sequence with a low peak-to-average power ratio is used as a preamble for synchronization and channel estimation. One of the more commonly used Preamble sequences is the binary PN sequence. The binary PN sequence is used in the IEEE802.16e standard, and its PAPR value reaches above 4dB.

发明内容 Contents of the invention

本发明实施例提供一种快速小区搜索方法，及基于该搜索方法的发射端装置和接收端装置。Embodiments of the present invention provide a fast cell search method, and a transmitter device and a receiver device based on the search method.

一种快速小区搜索方法，包括：构造基于序列类别索引的基本序列；将序列索引映射到基站标识；对所述基本序列进行离散傅立叶变换DFT或离散傅立叶逆变换IDFT，将变换后的序列作为参考序列；发送参考序列。一种快速小区搜索方法，包括：接收包括基于基本序列的参考序列；确定所述参考序列的序列类别索引；将所述序列类别索引映射到基站标识。A fast cell search method, comprising: constructing a basic sequence based on a sequence category index; mapping the sequence index to a base station identifier; performing discrete Fourier transform DFT or inverse discrete Fourier transform IDFT on the basic sequence, and using the transformed sequence as a reference Sequence; send reference sequence. A fast cell search method, comprising: receiving a reference sequence including a basic sequence; determining a sequence type index of the reference sequence; and mapping the sequence type index to a base station identifier.

一种发射端装置包括原始序列构造模块、序列分配模块、参考序列生成模块，其中：A transmitter device includes an original sequence construction module, a sequence allocation module, and a reference sequence generation module, wherein:

基本序列构造模块，用于构造基本序列；The basic sequence construction module is used to construct the basic sequence;

序列分配模块，用于唯一地将序列类别索引映射到多个或单个基站标识；a sequence allocation module for uniquely mapping sequence category indices to multiple or single base station identities;

参考序列生成模块，用于将分配给各基站的基本序列进行DFT或IDFT，得到的序列作为参考序列。The reference sequence generation module is used to perform DFT or IDFT on the basic sequences assigned to each base station, and use the obtained sequences as reference sequences.

一种接收端装置，包括：参考序列接收模块、序列索引确定模块、基站标识识别模块，其中：A receiver device, comprising: a reference sequence receiving module, a sequence index determining module, and a base station identification module, wherein:

参考序列接收模块，用于接收包括基于基本序列的参考序列；A reference sequence receiving module, configured to receive a reference sequence including a basic sequence;

序列索引确定模块，用于确定接收到的参考序列的序列类别索引；A sequence index determination module, configured to determine the sequence category index of the received reference sequence;

基站标识识别模块，用于将确定的序列类别索引映射到基站标识。The base station identification identification module is configured to map the determined sequence category index to the base station identification.

本发明实施例提供的参考序列具有低的PAPR值(接近0dB)，并且基于此特定的参考序列可以提供良好的小区检测性能。另外，基于本发明实施例的小区检测算法简单，没有给系统带来任何复杂性增加，有利于快速小区检测，小区切换等。The reference sequence provided by the embodiment of the present invention has a low PAPR value (close to 0dB), and based on this specific reference sequence, good cell detection performance can be provided. In addition, the cell detection algorithm based on the embodiment of the present invention is simple, does not bring any complexity increase to the system, and is beneficial to fast cell detection, cell switching, and the like.

附图说明 Description of drawings

图1为本发明实施例的发送端处理流程图；FIG. 1 is a flow chart of sending end processing according to an embodiment of the present invention;

图2为本发明实施例的发送端可选处理流程图一；FIG. 2 is an optional processing flowchart 1 of the sending end according to an embodiment of the present invention;

图3为本发明实施例的接收端处理流程图；FIG. 3 is a flow chart of receiving end processing according to an embodiment of the present invention;

图4为本发明实施例的接收端可选处理流程图一；FIG. 4 is an optional processing flowchart 1 of the receiving end according to an embodiment of the present invention;

图5为本发明实施例的接收端可选处理流程图二；FIG. 5 is a second optional processing flowchart of the receiving end according to the embodiment of the present invention;

图6为本发明实施例的发送端可选处理流程图二；FIG. 6 is a second optional processing flowchart of the sending end according to the embodiment of the present invention;

具体实施方式 Detailed ways

本发明实施例提供一种快速小区搜索方法，通过构造特殊参考序列实现小区的快速搜索。本发明实施例还提供了一种用于小区搜索的发射端装置和接收端装置，以下分别进行详细说明。An embodiment of the present invention provides a fast cell search method, which realizes fast cell search by constructing a special reference sequence. The embodiment of the present invention also provides a transmitter device and a receiver device for cell search, which will be described in detail below.

实施例一Embodiment one

A、构造参考序列，参考序列的构造取决于至少两个因素，即网络中参考序列数目K和所需的序列长度Np。本实施例时域参考符号是OFDM符号，该符号基于N点离散傅立叶逆变换IDFT。A. Construct a reference sequence. The construction of a reference sequence depends on at least two factors, namely the number K of reference sequences in the network and the required sequence length Np. The time-domain reference symbol in this embodiment is an OFDM symbol, and the symbol is based on an N-point inverse discrete Fourier transform IDFT.

首先构造基本序列：First construct the basic sequence:

$x x ((k k)) = = b b \cdot \cdot exp exp ((- - j j ((22 πμ πμ \frac{k k}{{N N}_{G G}} + + c c)))) - - - - - - ((11))$

其中，μ＝0，1，...，N_G-1对应序列的“类别”，where μ = 0, 1, ..., N _G -1 corresponds to the "category" of the sequence,

k＝0，1，...，N_G-1是序列中项的索引，k = 0, 1, ..., N _G -1 is the index of the item in the sequence,

b，c为任意实数，且b≠0。为满足网络中参考序列数目的要求，只需要满足N_G>K。b, c are any real numbers, and b≠0. In order to meet the requirement of the number of reference sequences in the network, it is only necessary to satisfy N _G >K.

取决于对b，c的特定选择，每个基本序列类别可以具有无限的序列数目，但是每个类别中仅有一个序列用于构造一个参考序列。每个类别索引“μ”在每个参考序列上产生了不同的相位斜坡特性。为表述方便，以下均以b＝1，c＝0作为示例，不代表b，c的取值仅限于此。Depending on the particular choice of b, c, each basic sequence class can have an infinite number of sequences, but only one sequence in each class is used to construct a reference sequence. Each class index "μ" produces a different phase ramp characteristic on each reference sequence. For the convenience of expression, b=1 and c=0 are taken as examples below, which does not mean that the values of b and c are limited to this.

然后对N_G个上述构造的基本序列分别进行T点(T≥N_G)DFT，得到的序列可以表示为：Then perform T-point (T≥N _G ) DFT on the N _G basic sequences constructed above, and the obtained sequences can be expressed as:

$X x ((m m)) = = DFT DFT ((x x ((k k)))) = = {Σ Σ}_{k k = = 00}^{T T - - 11} x x ((k k)) exp exp ((- - j j 22 π π ((\frac{μ μ}{{N N}_{G G}} + + \frac{m m}{T T})) k k)) - - - - - - ((22))$

其中，k＝N_G，...，T-1时，x(k)＝0。Wherein, k=N _G , . . . , when T-1, x(k)=0.

当 $\frac{μ}{N_{G}} + \frac{m}{T} = 1$ 时，X(m)出现峰值。when $\frac{μ}{N_{G}} + \frac{m}{T} = 1$ When , X(m) peaks.

也可以对构造的N_G个基本序列进行T点(T≥N_G)IDFT(逆DFT)，得到的序列可以表示为：T-point ( _T≥NG ) IDFT (inverse DFT) can also be performed on the constructed N _G basic sequences, and the obtained sequence can be expressed as:

$X x ((m m)) = = IDFT IDFT ((x x ((k k)))) = = {Σ Σ}_{k k = = 00}^{T T - - 11} x x ((k k)) exp exp ((j j 22 π π ((\frac{m m}{T T} - - \frac{μ μ}{{N N}_{G G}})) k k)) - - - - - - ((33))$

当 $\frac{μ}{N_{G}} = \frac{m}{T}$ 时，X(m)出现峰值。when $\frac{μ}{N_{G}} = \frac{m}{T}$ When , X(m) peaks.

将上述经过DFT或IDFT变换后得到的长度为T的序列的集合作为频域参考序列集合。对于T等于Np的情况，生成频域参考序列不需要再附加其他操作，参见图1；对于T不等于Np的情况，可以对长度为T的序列集合进行修改，以生成所需长度的频域参考序列集合，参见图2，其中修改包括，对原序列插值，或是截断到所需序列长度Np等操作。选择合适的DFT/IDFT点数，可以使得，在所有参考子载波上只有一个子载波上的数据为非零值，其它子载波上数据均为0，即频域序列可以看作为一冲击函数序列，故此频域参考序列集合具有最优的互相关性。The above-mentioned set of sequences of length T obtained after DFT or IDFT transformation is used as a set of frequency domain reference sequences. For the case where T is equal to Np, no additional operations are required to generate the frequency domain reference sequence, see Figure 1; for the case where T is not equal to Np, the sequence set of length T can be modified to generate a frequency domain of the required length Refer to Figure 2 for the reference sequence set, where modification includes operations such as interpolating the original sequence, or truncating to the required sequence length Np. Selecting the appropriate number of DFT/IDFT points can make the data on only one subcarrier on all reference subcarriers have a non-zero value, and the data on other subcarriers are all 0, that is, the frequency domain sequence can be regarded as an impact function sequence, Therefore, the frequency-domain reference sequence set has optimal cross-correlation.

按照预先规定的映射方式，将序列项分配到频域N个子载波中的Np个参考子载波集合上(N为OFDM符号基于的离散傅立叶变换DFT的点数，Np即为上述提到的所需序列长度，所需序列长度等于频域参考子载波的个数)。经过N点IDFT，将上述OFDM符号频域数据变换到时域，作为发送序列，表达式为：According to the pre-specified mapping method, the sequence items are allocated to the Np reference subcarrier sets in the N subcarriers in the frequency domain (N is the number of points of the discrete Fourier transform DFT based on the OFDM symbol, and Np is the required sequence mentioned above length, the required sequence length is equal to the number of reference subcarriers in the frequency domain). After N-point IDFT, the above OFDM symbol frequency domain data is transformed into the time domain as a transmission sequence, and the expression is:

$\begin{matrix} s the s ((n no)) = = IDFT IDFT ((X x' ' ((m m' ')))) m m' ' = = 0,1 0,1,, L L,, N N - - 11 \\ = = {Σ Σ}_{m m = = 00}^{N N - - 11} X x' ' ((m m' ')) exp exp ((- - j j 22 π π \frac{m m' ' n no}{N N})) \end{matrix} - - - - - - ((44))$

其中，X′(m′)为完成子载波映射后的频域序列，m′为子载波序号。Wherein, X'(m') is the frequency domain sequence after the subcarrier mapping is completed, and m' is the sequence number of the subcarrier.

时域中发射的最终参考序列可以是循环扩展的，其中循环扩展长度典型地长于所期望的信道最大延迟扩展(LD)。在这种情况下，所发送的最终序列的长度等于N与循环扩展长度L_CP之和。循环扩展可以包括前缀、后缀或前缀与后缀的组合。循环扩展是OFDM通信系统的固有部分。可以证明，时域参考序列仍然具有最优互相关性。The final reference sequence transmitted in the time domain may be cyclically extended, where the cyclic extension length is typically longer than the expected maximum delay spread (LD) of the channel. In this case, the length of the final sequence sent is equal to the sum of N and the cyclic extension length L _CP . Cyclic extensions can include prefixes, suffixes, or a combination of prefixes and suffixes. Cyclic extension is an inherent part of OFDM communication systems. It can be shown that the time-domain reference sequence still has optimal cross-correlation.

B、进行参考序列的分配，即唯一地将序列类别索引映射到多个基站/单个基站标识。每个基站可以在任何传输间隔、以任何次数地使用一个或多个基本序列。此外，可以给每个基站分配来自K个基本序列集合的不同基本序列，由该K个基本序列进后续处理后得到的参考序列集合被设计为具有最优的互相关性质。实际信号可以是所分配序列的不同函数的结果。例如，所应用的函数是序列的循环移位。B. Allocation of the reference sequence, that is, uniquely mapping the sequence category index to multiple base stations/single base station identifier. Each base station may use one or more base sequences any number of times in any transmission interval. In addition, different basic sequences from K basic sequence sets can be assigned to each base station, and the reference sequence set obtained after subsequent processing of the K basic sequences is designed to have optimal cross-correlation properties. The actual signal can be the result of a different function of the assigned sequence. For example, the function applied is a cyclic shift of the sequence.

也可以直接将图1中步骤103得到的N_G个长度为Np的频域参考序列组成的集合中的K个序列，分别分配给多个基站/单个基站，并分别唯一地将基本序列类别索引映射到多个基站/单个基站标识，则每个基站只需进行子载波映射、频时变换以及循环扩展操作。It is also possible to directly assign the K sequences in the set of NG frequency-domain reference sequences of length Np obtained in step 103 in _FIG . Mapped to multiple base stations/single base station identifier, each base station only needs to perform subcarrier mapping, frequency-time transformation and cyclic extension operations.

C、接下来进行基于上述操作的小区搜索。C. Next, perform cell search based on the above operations.

假设已经完成了OFDM符号的定时和频率偏移估计和校正，从校正的定时点，通过DFT将所接收的时域数据变换到频域，基于发射端规定的子载波映射方式进行子载波解映射。Assuming that the timing and frequency offset estimation and correction of OFDM symbols have been completed, from the corrected timing point, the received time domain data is transformed into the frequency domain by DFT, and the subcarrier demapping is performed based on the subcarrier mapping method specified by the transmitter .

将子载波解映射后的频域数据表示为Y(m)，其中m(从0到Np-1)是参考子载波的索引。由前面的讨论知道，频域数据的峰值位置由μ值决定，由Y(m)的峰值位置可以计算出μ值。也即，类别索引(或序列索引)信息“μ”被承载在Y(m)的峰值位置中，通过分析Y(m)的峰值位置，可以检测到对应于参考序列索引的“μ”。Y(m)的峰值位置n_max与对应的发射序列类别索引μ的映射关系被确定为：The frequency domain data after subcarrier demapping is denoted as Y(m), where m (from 0 to Np-1) is the index of the reference subcarrier. It is known from the previous discussion that the peak position of the frequency domain data is determined by the value of μ, and the value of μ can be calculated from the peak position of Y(m). That is, the category index (or sequence index) information "μ" is carried in the peak position of Y(m), and by analyzing the peak position of Y(m), "μ" corresponding to the reference sequence index can be detected. The mapping relationship between the peak position n _max of Y(m) and the corresponding emission sequence category index μ is determined as:

$μ = N_{G} (1 - \frac{n_{\max}}{T}),$ (对应于X(m)＝DFT(x(k))) $μ = N_{G} (1 - \frac{{no}_{\max}}{T}),$ (corresponding to X(m)=DFT(x(k)))

或 $μ = N_{G} \frac{n_{\max}}{T},$ (对应于X(m)＝IDFT(x(k)))，其中n_max为Y(m)的峰值位置。由以上公式计算出的μ不一定是整数，针对这种情况，取最接近于以上计算结果的整数值作为μ的值。or $μ = N_{G} \frac{{no}_{\max}}{T},$ (corresponding to X(m)=IDFT(x(k))), where n _max is the peak position of Y(m). The μ calculated by the above formula is not necessarily an integer. In this case, the integer value closest to the above calculation result is taken as the value of μ.

由此可以得到所识别的峰值位置与序列类别索引之间的映射关系。序列类别索引对应于发送参考序列的源基站标识。这样接收端根据接收到的信号峰值的位置，可以计算出源基站标识，进而完成小区搜索。参见图3。In this way, the mapping relationship between the identified peak positions and sequence category indexes can be obtained. The sequence class index corresponds to the identity of the source base station that sent the reference sequence. In this way, the receiving end can calculate the identity of the source base station according to the position of the peak value of the received signal, and then complete the cell search. See Figure 3.

可以使用常规的峰值检测方法，如将样本的幅度同阈值进行比较，或直接峰值检测等等。如果存在多个接收序列，则将显示多个峰值。Conventional peak detection methods can be used, such as comparing the amplitude of the sample to a threshold, or direct peak detection, etc. If there are multiple received sequences, multiple peaks will be displayed.

也可以将所识别的μ映射到附加的可能发射序列索引集合中，该发射序列索引集合对应于所识别的μ附近。参见图4。当在系统中使用的一些值“μ”紧密间隔时，噪声或干扰可以使峰值出现在接近但不是位于期望用于索引“μ”的相同位置处。通过在峰值附近进行搜索，可以识别多于一个候选序列索引用于进一步检查(如在多个参考信号传输周期中)。例如，对多个参考信号传输周期上的结果进行组合、比较、多数表决等等，以帮助识别所接收的“μ”的一个值或多个值。总之，我们可以将所识别的μ映射到附加的可能发射序列索引中，该发射序列索引对应于所识别的μ附近。The identified μ may also be mapped into an additional set of possible shot sequence indices corresponding to the identified neighborhood of μ. See Figure 4. When some of the values "μ" used in the system are closely spaced, noise or interference can cause peaks to appear close to but not at the same positions expected for the index "μ". By searching around the peak, more than one candidate sequence index can be identified for further inspection (eg, over multiple reference signal transmission periods). For example, the results over multiple reference signal transmission periods are combined, compared, majority voted, etc. to help identify the received value or values of "μ". In summary, we can map the identified μ into additional possible firing sequence indices corresponding to the identified vicinity of μ.

在检测到多个序列的情况下，可以使用抵消的方法，以改善检测弱序列的可能性。参见图5，可以首先识别第一参考序列，估计涉及已知参考序列的信道响应，重新构造由第一已知序列及其信道响应贡献的接收信号部分，从接收信号中移除该部分，并且随后执行类似于在第一序列检测中所需的步骤以获得第二序列索引。通过该过程可以继续，直到检测到全部序列。In cases where multiple sequences are detected, a method of cancellation can be used to improve the probability of detecting weak sequences. Referring to Figure 5, one may first identify the first reference sequence, estimate the channel response involving the known reference sequence, reconstruct the portion of the received signal contributed by the first known sequence and its channel response, remove this portion from the received signal, and Steps similar to those required in the first sequence detection are then performed to obtain the second sequence index. This process can continue until all sequences are detected.

在接收端，还可以通过先对参考符号进行信道均衡，去除信道影响后，再进行峰值检测等操作。At the receiving end, it is also possible to perform channel equalization on the reference symbols first, remove the influence of the channel, and then perform operations such as peak detection.

实施例二Embodiment two

本实施例提供的小区搜索方法与实施例一类似。构造基本序列方法同实施例一，只是直接对基本N_G长度的序列进行修改，使其序列长度等于Np，然后再进行实施例一中的中DFT或IDFT操作，此时DFT/IDFT的点数为Np，后续操作与实施例一相同。参见图6The cell search method provided in this embodiment is similar to that in Embodiment 1. The method of constructing the basic sequence is the same as in the first embodiment, except that the sequence of the basic _NG length is directly modified so that the sequence length is equal to Np, and then the DFT or IDFT operation in the first embodiment is performed. At this time, the points of DFT/IDFT are Np, the subsequent operation is the same as that in Embodiment 1. See Figure 6

接收端的处理方法同实施例一，只是μ与n_max之间的关系式变为：The processing method at the receiving end is the same as that in Embodiment 1, except that the relational expression between μ and n _max becomes:

或 $μ = \frac{n_{\max}}{T} N_{G},$ (对应于X(m)＝IDFT(x(k)))，其中n_max为Y(m)的峰值位置。序列类别索引对应于发送参考序列的源基站标识。这样接收端根据接收到信号的峰值位置，可以计算出源基站标识，进而完成小区搜索。or $μ = \frac{{no}_{\max}}{T} N_{G},$ (corresponding to X(m)=IDFT(x(k))), where n _max is the peak position of Y(m). The sequence class index corresponds to the identity of the source base station that sent the reference sequence. In this way, the receiving end can calculate the identity of the source base station according to the peak position of the received signal, and then complete the cell search.

相应于上面描述的小区搜索方法，本发明实施例还提供一种发射端设备和接收端设备。Corresponding to the cell search method described above, the embodiment of the present invention further provides a transmitting end device and a receiving end device.

发射端设备包括基本序列构造模块、序列分配模块、参考序列生成模块。其中，The transmitter device includes a basic sequence construction module, a sequence allocation module, and a reference sequence generation module. in,

这里，基本序列构造模块基于式(1)构造包含特定类别索引μ的基本序列。Here, the basic sequence construction module constructs a basic sequence containing a specific category index μ based on formula (1).

接收端设备包括、参考序列接收模块、序列索引确定模块、基站标识识别模块。其中，The receiver device includes a reference sequence receiving module, a sequence index determining module, and a base station identification module. in,

本领域普通技术人员可以理解上述实施例的各种方法中的全部或部分步骤是可以通过程序来指令相关的硬件来完成，该程序可以存储于一计算机可读存储介质中，存储介质可以包括：ROM、RAM、磁盘或光盘等。Those of ordinary skill in the art can understand that all or part of the steps in the various methods of the above-mentioned embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the storage medium can include: ROM, RAM, disk or CD, etc.

本文中应用具体个例对本发明的原理及实施方式进行了阐述，以上实施例的说明只是用于帮助理解本发明的方法及其核心思想；同时，对于本领域的一般技术人员，依据本发明的思想，在具体实施方式及应用范围上均会有改变之处，综上所述，本说明书内容不应理解为对本发明的限制。The application of specific examples herein has explained the principle and implementation of the present invention, and the description of the above embodiments is only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to the present invention Thoughts, specific implementation methods and scope of application all have changes. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A fast cell search method, characterized in that it comprises:

Constructing a basic sequence based on the sequence category index; mapping the sequence category index to the base station identifier; performing discrete Fourier transform DFT or inverse discrete Fourier transform IDFT on the basic sequence, and using the transformed sequence as a reference sequence; sending the reference sequence.

2. The cell search method according to claim 1, wherein the basic sequence expression is

x x ((k k)) = = b b \cdot \cdot exp exp ((- - j j ((22 πμ πμ \frac{k k}{{N N}_{G G}} + + c c))))

Among them, μ represents the index of the sequence category, k represents the index of the item in the sequence, b and c are any real numbers, and b≠0, N _G is determined by the actual number of reference sequences required.

3. The cell search method according to claim 1, characterized in that, after performing discrete Fourier transform (DFT) or inverse discrete Fourier transform (IDFT) on the basic sequence, further comprising: modifying the transformed sequence, the Modifications include interpolation or truncation.

4. The cell search method according to claim 1, characterized in that after constructing the basic sequence based on the sequence type index, further comprising: modifying the basic sequence, the modification including interpolation or truncation.

5. A fast cell search method, characterized in that it comprises:

Receiving a reference sequence including a base sequence; determining a sequence category index of the reference sequence; mapping the sequence category index to a base station identifier.

6. The cell search method according to claim 5, wherein said determining the sequence type index comprises calculating the sequence type index at the receiving end according to the peak position of the received signal.

7. A transmitter device for fast cell search, characterized in that it includes an original sequence construction module, a sequence allocation module, and a reference sequence generation module, wherein,

The basic sequence construction module is used to construct the basic sequence;

a sequence allocation module for uniquely mapping sequence category indices to multiple or single base station identities;

The reference sequence generation module is used to perform DFT or IDFT on the basic sequences assigned to each base station, and use the obtained sequences as reference sequences.

8. The transmitter device according to claim 7, wherein the basic sequence is based on a sequence type index.

9. A receiver device, used for fast cell search, comprising: a reference sequence receiving module, a sequence index determining module, and a base station identification module, wherein,

A reference sequence receiving module, configured to receive a reference sequence including a basic sequence;

A sequence index determination module, configured to determine the sequence category index of the received reference sequence;

The base station identification identification module is configured to map the determined sequence category index to the base station identification.

10. The receiver device according to claim 9, wherein the sequence index determination module calculates the sequence category index according to the position of the peak value of the received signal.