WO2012000283A1 - 一种实现快速频率扫描的方法和移动终端 - Google Patents

一种实现快速频率扫描的方法和移动终端 Download PDF

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Publication number
WO2012000283A1
WO2012000283A1 PCT/CN2010/079243 CN2010079243W WO2012000283A1 WO 2012000283 A1 WO2012000283 A1 WO 2012000283A1 CN 2010079243 W CN2010079243 W CN 2010079243W WO 2012000283 A1 WO2012000283 A1 WO 2012000283A1
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Prior art keywords
frequency
mobile terminal
domain signal
signal
frequency point
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PCT/CN2010/079243
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English (en)
French (fr)
Inventor
李焱
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中兴通讯股份有限公司
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Publication of WO2012000283A1 publication Critical patent/WO2012000283A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/02—Power saving arrangements
    • H04W52/0209—Power saving arrangements in terminal devices
    • H04W52/0225—Power saving arrangements in terminal devices using monitoring of external events, e.g. the presence of a signal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present invention relates to a wireless communication method, and more particularly to a method and a mobile terminal for implementing fast frequency scanning.
  • frequency scanning is a very important step for a User Equipment (UE), that is, a mobile terminal.
  • UE User Equipment
  • a frequency sweep is also required when the mobile terminal is first turned on or when network signals cannot be detected.
  • the system presets possible frequency spacing, such as Global System for Mobile Communications (GSM) systems or Wideband Code Division Multiple Access (WCDMA) systems.
  • the preset frequency interval is 200 kHz, and the Long Term Evolution (LTE) system is 100 kHz.
  • a commonly used method for frequency scanning by a mobile terminal is to detect a Receive Signal Strength Indicator (RSI) at all possible frequencies. If the preset threshold is exceeded, the signal is considered to have a signal at this frequency. After scanning all the frequency bands, the frequency points exceeding the RSSI threshold are sorted according to the level of the RSSI value, and the mobile terminal performs a small area search for each frequency point according to the order.
  • the disadvantage of this method is that the search speed is slow.
  • the maximum band bandwidth may be 100 MHz. If the mobile terminal performs frequency scanning at intervals of 100 kHz, it needs to scan 1000 frequency points, considering the influence of Time Division Duplex (TDD) system (including uplink time slot and downlink time slot), for each frequency.
  • TDD Time Division Duplex
  • the RSSI scan time of the point cannot be less than 5ms, so at least 5s need to be scanned for the 100M frequency band.
  • the difficulty of frequency scanning is further increased.
  • the mobile terminal cannot determine the bandwidth of the base station transmitter, so the RSSI detection can only be performed with the smallest possible bandwidth at the frequency (for example, 1.4 ⁇ 5 ⁇ ), when the bandwidth of the base station transmitter is greater than the minimum bandwidth. Time (the transmitter's maximum bandwidth is 20MHz), if detected The RSSI is sorted. Due to the frequency selection, the energy of the selected center frequency is not necessarily large, which greatly reduces the accuracy of the detection, resulting in a long detection time.
  • the present invention provides a method and a mobile terminal for realizing fast frequency scanning to improve the speed of frequency scanning and improve the accuracy of the determined frequency point.
  • the present invention provides a method for implementing fast frequency scanning, comprising: a mobile terminal converting a received time domain signal into a frequency domain signal, and determining a frequency for accessing the network by scanning a power spectrum of a frequency domain signal of a frequency band to be scanned. point.
  • the method may further include: before the step of converting the received time domain signal into the frequency domain signal, the mobile terminal divides the received time domain signal into multiple time domain segment signals by using the reference duration T as a time interval, where each The time domain segment signals include at least one complete downlink subframe or time slot.
  • the step of converting the received time domain signal into the frequency domain signal by the mobile terminal may include: the mobile terminal sequentially performs time-frequency signal conversion on each time domain segment signal; or, the mobile terminal only has a signal strength greater than that in each time domain segment. The part of the threshold is subjected to time-frequency signal conversion.
  • the Fourier transform may be performed on the sample points of the time domain segment signal in units of the maximum Fourier transform point number supported by the mobile terminal, and the obtained Fourier transform is obtained.
  • the non-coherent accumulation is performed, and the accumulated result is used as the frequency domain signal corresponding to the time domain segment signal.
  • the method may further include: when the bandwidth of the to-be-scanned frequency band is greater than the maximum bandwidth supported by the mobile terminal, the mobile terminal sequentially splicing the frequency domain signals of the plurality of unit bandwidth into the to-be-scanned frequency band by using the maximum bandwidth supported by the mobile terminal. Frequency domain signal.
  • the step of determining a frequency point for accessing the network by scanning a power spectrum of the frequency domain signal of the frequency band to be scanned may include: scanning, by the mobile terminal, a power spectrum of the frequency domain signal of the frequency band to be scanned, and determining an effective frequency band, where the effective frequency band is The continuous frequency point is included and the power value corresponding to each frequency point is greater than a preset power threshold; the mobile terminal uses the frequency point in the determined effective frequency band as an alternative frequency point for accessing the network.
  • the mobile terminal may use, as a priority candidate frequency point, a frequency point in the effective frequency band that is smaller than a preset frequency interval from a center frequency point of the effective frequency band, and use other frequency points other than the priority candidate frequency point in the effective frequency band as The secondary candidate frequency points are prioritized, and the priority of each priority candidate frequency point is set in order from the near to the far distance from the center frequency point.
  • the present invention also provides a mobile terminal that implements fast frequency scanning, the mobile terminal includes a time-frequency transform module and a frequency point selection module; and the time-frequency transform module is configured to convert the received time domain signal into a frequency domain signal.
  • the frequency point selection module is configured to determine a frequency point for accessing the network by scanning a power spectrum of the frequency domain signal of the frequency band to be scanned.
  • the time-frequency transform module may be configured to convert the received time domain signal into a frequency domain signal by: dividing the time domain signal into a plurality of time domain segment signals by using a reference time length T, the plurality of time domain segment signals Each of the at least one complete downlink subframe or time slot; performing time-frequency signal conversion on each time domain segment signal in turn, or performing time-frequency signal only on a portion of the time domain segment whose signal strength is greater than a preset threshold Transform.
  • the frequency selection module may be configured to determine a frequency point for accessing the network by: scanning a power spectrum of the frequency domain signal of the frequency band to be scanned, determining an effective frequency band, wherein the effective frequency band includes consecutive frequency points and each The power value corresponding to the frequency point is greater than a preset power threshold; the effective frequency band intermediate frequency point is used as an alternative frequency point for accessing the network.
  • the frequency selection module may be configured to use a frequency point in the effective frequency band that is less than a preset interval threshold from a center frequency point of the effective frequency band as a priority candidate frequency point, and other than the priority candidate frequency point in the effective frequency band.
  • the frequency point is used as the secondary priority candidate frequency point, and the priority of each priority candidate frequency point is set according to the distance from the center frequency point from near to far.
  • the present invention is directed to the characteristics of the LTE system, and uses a frequency speech detection method to transform a time domain signal in the entire measured bandwidth to a frequency domain signal, and then scans the spectrum of the received signal to determine a possible center frequency point, which is preferentially performed. Detection.
  • the invention can improve the speed of frequency scanning and reduce the time required for frequency scanning, thereby achieving the effect of fast booting and reducing the power consumption of the mobile terminal receiver.
  • FIG. 1 is a structural diagram of a structure of a mobile terminal that implements fast frequency scanning in an embodiment
  • FIG. 2 is a schematic diagram of a method of implementing fast frequency scanning in an embodiment.
  • the mobile terminal includes a time-frequency transform module and a frequency point selection module.
  • the time-frequency transform module is configured to convert the received time domain signal into a frequency domain signal;
  • the frequency point selection module is arranged to determine a frequency point for accessing the network by scanning a power spectrum of the frequency domain signal of the frequency band to be scanned.
  • the time-frequency transform module may be configured to: divide the time domain signal into a plurality of time domain segment signals by using a reference time length T as a time interval, wherein each time domain segment signal includes at least one complete downlink subframe or time slot;
  • the time domain segment signal performs time-frequency signal conversion, or only time-frequency signal conversion is performed for a portion of each time domain segment whose signal strength is greater than a preset threshold.
  • the time-frequency transform module may be configured to perform time-frequency signal conversion on the time domain segment signal by: performing multiple Fourier transform on the sample points of the one-time domain segment signal in units of the maximum Fourier transform point number supported by the mobile terminal, The Fourier transform result is subjected to non-coherent accumulation as a frequency domain signal corresponding to the time domain segment signal.
  • the time-frequency transform module is further configured to sequentially splicing frequency domain signals of multiple unit bandwidths into frequency bands to be scanned when the bandwidth of the frequency band to be scanned is greater than the maximum bandwidth supported by the mobile terminal, with the maximum bandwidth supported by the bandwidth. Frequency domain signal.
  • the frequency selection module may be configured to scan the power spectrum of the frequency domain signal of the frequency band to be scanned to determine the effective frequency band, wherein the effective frequency band includes consecutive frequency points and the power value corresponding to each frequency point is greater than the preset power. Threshold, the effective frequency band IF point is used as an alternative frequency point for accessing the network.
  • the frequency point selection module may be further configured to: use a frequency point in the effective frequency band that is smaller than a preset frequency interval from a center frequency point of the effective frequency band as a priority candidate frequency point, and use other frequency points in the effective frequency band as a secondary priority candidate frequency. Point; The priority of each priority candidate frequency point is set in order from the near to the far distance from the center frequency point.
  • the method for implementing fast frequency scanning includes:
  • Step 201 The mobile terminal converts the received time domain signal into a frequency domain signal.
  • Step 202 Determine a frequency point for accessing the network by scanning a power spectrum of the frequency domain signal of the frequency band to be scanned.
  • the process of converting the received time domain signal into the frequency domain signal by the mobile terminal in step 201 may also use the following technical means:
  • a fast Fourier transform is generally used.
  • the mobile terminal supporting the LTE system has an FFT module without adding new hardware devices.
  • the mobile terminal divides the time domain signal into multiple time domain segment signals by using the reference time length T as a time interval, and sequentially processes each time domain segment signal, and signals each segment of the time domain segment in units of the maximum number of FFT points supported by the mobile terminal. After the sample is subjected to multiple FFT transformations, the FFT result is obtained for non-coherent accumulation as the frequency domain signal corresponding to the current segment signal.
  • TDD for example, LTE-TDD
  • the mobile terminal does not know the uplink and downlink resource configuration of the system when performing frequency scanning. To ensure that the downlink signal can be detected, the reference duration T cannot be too short.
  • the mobile terminal obtains more samples of the time domain signal, but usually the receiver cannot support the FFT with a large number of points.
  • the maximum FFT point supported by the mobile terminal is 2048.
  • the LTE-TDD includes at least one downlink subframe every 5 ms, and generally has a T of at least 5 ms. Taking T as 10ms as an example, the mobile terminal receiver obtains 307,200 sample points in the T time period with a sampling rate of 30.72M, and the receiver supports up to 2048 points FFT, so it can continuously perform 2048 points of FFT. Then, the obtained signal is subjected to non-coherent accumulation as a frequency domain signal corresponding to the current segment signal.
  • the way of non-coherent accumulation can be:
  • r(n) is the received signal
  • L is the number of times the FFT is performed
  • R is the power spectrum of the received signal.
  • a preset threshold may be set for the time domain segment signal, and the mobile terminal only performs the time when the signal strength of the time domain segment signal is greater than the preset threshold. Frequency signal conversion, the conversion method is the same as above. For the portion of the time domain segment where the signal strength is less than or equal to the preset threshold, no time-frequency signal conversion is required, thereby improving the frequency scanning efficiency and saving the power consumption of the mobile terminal.
  • the bandwidth of the frequency band to be scanned is larger than the maximum bandwidth supported by the mobile terminal, for example, the maximum frequency band of LTE is 100 MHz, and the effective bandwidth of the receiver is 18 MHz, and the mobile terminal uses a maximum bandwidth supported by the mobile terminal, and multiple unit bandwidths are used.
  • the frequency domain signals are sequentially spliced into frequency domain signals of the frequency band to be scanned.
  • the power spectrum of the signal in the frequency band to be scanned can be obtained by step 201.
  • the above method takes the scanning of the 100 MHz frequency band as an example. Assuming that the maximum bandwidth of the mobile terminal receiver is 18 MHz, it takes only 30 ms to complete the scanning of the 100 MHz frequency band, which is much smaller than the traditional time domain RSSI detecting side. Law.
  • the method for determining the frequency point for accessing the network by scanning the power spectrum of the frequency domain signal of the frequency band to be scanned in step 202 may use the following technical means:
  • the mobile terminal scans the power spectrum of the frequency domain signal of the scanning frequency band to determine the effective frequency band, wherein the effective frequency band includes consecutive frequency points and the power value corresponding to each frequency point is greater than a preset power threshold, and the power threshold may be It is an absolute threshold, or it can be a relative threshold set according to the average power of the channel.
  • the bandwidth threshold may be set. When the bandwidth of the effective frequency band obtained by the mobile terminal is less than the bandwidth threshold, the effective frequency band is updated to the invalid bandwidth.
  • This bandwidth threshold can be set to 1.4MHz. In order to reduce the probability of missed detection, it can be set to 1MHz. The value of this bandwidth threshold can also be set differently according to performance requirements.
  • the mobile terminal When the mobile terminal detects the power spectrum of the frequency domain signal, it detects it according to a certain bandwidth, and the bandwidth can be from 100 kHz to 1.4 MHz. Since the carrier spacing under the 1.4M bandwidth is around 320kHz, 300kHz is an excellent choice.
  • the mobile terminal uses the effective frequency band intermediate frequency point as an alternative frequency point for accessing the network. All the frequency points in the effective frequency band can be used as the candidate frequency point, and the frequency point of the effective frequency band and the center frequency point of the effective frequency band is less than the preset interval threshold as the priority candidate frequency point, and other frequencies in the effective frequency band are used.
  • the point is used as the secondary priority candidate frequency point, and the priority of each priority candidate frequency point is set according to the distance from the center frequency point from near to far.
  • the order of priority of the priority candidate frequency points from high to low corresponds to the distance from the near to far distance from the center frequency point, that is, the priority of the priority candidate frequency point which is closer to the frequency point is higher.
  • the mobile terminal When detecting the candidate frequency point, the mobile terminal first detects the priority candidate frequency point, and then detects the secondary priority candidate frequency point, and detects the priority candidate frequency, and detects the priority according to the priority from high to low, at a certain frequency point.
  • the frequency is determined as the frequency of accessing the network.
  • the core idea of the invention is to detect the spectrum of the signal and to determine the possible center frequency points based on the spectrum. Compared with the traditional method of directly utilizing the time domain signal RSSI, the sweep speed can be improved, the boot time can be shortened, and the power consumption can be reduced.
  • the invention may have other various embodiments without departing from the spirit and spirit of the invention. However, such corresponding changes and modifications are intended to be included within the scope of the appended claims.
  • the present invention can increase the speed of frequency scanning and reduce the time required for frequency scanning, thereby achieving the effect of fast booting and reducing the power consumption of the mobile terminal receiver.

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  • Computer Networks & Wireless Communication (AREA)
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Description

一种实现快速频率扫描的方法和移动终端
技术领域
本发明涉及无线通信方法， 尤其涉及一种实现快速频率扫描的方法和移 动终端。
背景技术
在无线通信系统尤其是蜂窝通信系统中， 频率扫描对于用户设备 ( User Equipment, 简称 UE ) 即移动终端是一个非常重要的步骤。 当移动终端开机 后， 会根据自己预先存储的频点进行优先接入尝试， 如果失败， 则需要在其 它所有可能的频带中进行频率扫描找到可以接入的频点， 然后接入网络。 当 移动终端初次开机时或者无法检测到网络信号时也需要进行频率扫描。
在多数蜂窝系统中， 系统会预先设定可能的频点间隔， 例如全球移动通 讯（ Global System for Mobile Communications, 简称 GSM ) 系统或宽带码分 多址（ Wideband Code Division Multiple Access , 简称 WCDMA ) 系统中预设 的频点间隔为 200kHz , 长期演进（ Long Term Evolution , 简称 LTE ) 系统中 为 100kHz。 移动终端进行频率扫描时常用的方法是， 对所有可能频点上的接 收信号能量指示 （Receive Signal Strength Indicator, 简称 RSSI )进行检测。 如果超过预设门限，则认为此频点上有信号。扫描完所有频带后，对超过 RSSI 门限的频点根据 RSSI值的高低进行排序，移动终端按此排序对各频点进行小 区搜索。 这种方法的缺点是搜索速度慢。 例如， 对于 LTE系统， 最大频带带 宽可能为 100MHz。 如果移动终端按照 100kHz的间隔进行频率扫描， 则需要 扫描 1000个频点， 考虑到时分双工（ Time Division Duplex, 简称 TDD )系统 的影响（包括上行时隙和下行时隙 ) , 对每个频点的 RSSI扫描的时间不能小 于 5ms, 那么对于 100M的频带至少需要扫描 5s。
在 LTE系统中， 由于支持多种带宽， 则更增加了频率扫描的难度。 在进 行频率扫描时， 移动终端无法确定基站发射机的带宽， 因此只能用该频点上 的最小可能带宽进行 RSSI检测 （例如可以是 1.4ΜΗζ~5ΜΗζ ) , 当基站发射 机的带宽大于最小带宽时（发射机的最大带宽为 20MHz ) , 如果根据检测到 的 RSSI进行排序，由于频点选择的原因，选择的中心频点的能量不一定很大， 从而大大降低检测的准确性， 导致检测时间过长。
发明内容
为了解决上述技术问题本发明提供了一种实现快速频率扫描的方法和移 动终端， 以提高频率扫描的速度， 提高确定的频点的精确度。
本发明提供了一种实现快速频率扫描的方法， 包括： 移动终端将接收到 的时域信号转换为频域信号， 通过扫描待扫描频带的频域信号的功率谱确定 用于接入网络的频点。
上述方法在将接收到的时域信号转换为频域信号的步骤之前还可以包 括： 移动终端以参考时长 T为时间间隔将接收到的时域信号分为多个时域段 信号， 其中， 每个时域段信号至少包括一个完整的下行子帧或者时隙。 移动 终端将接收到的时域信号转换为频域信号的步骤可包括： 移动终端依次对各 时域段信号进行时频信号变换； 或者， 移动终端只对每个时域段内信号强度 大于预设门限的部分进行时频信号变换。 其中， 移动终端对一时域段信号进 行时频信号变换时， 可以以该移动终端支持的最大傅利叶变换点数为单位对 该时域段信号的釆样点进行多次傅利叶变换， 将得到的傅利叶变换结果进行 非相干累加， 将累加结果作为该时域段信号对应的频域信号。
上述方法还可以包括： 当待扫描频带的带宽大于移动终端所支持的最大 带宽时， 该移动终端以所支持的最大带宽为单位带宽， 将多个单位带宽的频 域信号依次拼接成待扫描频带的频域信号。
通过扫描待扫描频带的频域信号的功率谱确定用于接入网络的频点的步 骤可包括： 移动终端对待扫描频带的频域信号的功率谱进行扫描， 确定有效 频段， 其中， 有效频段中包含连续的频点并且每个频点对应的功率值均大于 预设的功率门限； 移动终端将确定的有效频段中的频点作为用于接入网络的 备选频点。 其中， 移动终端可以将有效频段中与有效频段的中心频点的距离 小于预设间隔门限的频点作为优先备选频点， 将有效频段中除优先备选频点 之外的其它频点作为次优先备选频点， 并根据离中心频点的距离从近到远的 顺序设置各优先备选频点的优先级。 本发明还提供了一种实现快速频率扫描的移动终端， 所述移动终端包括 时频变换模块和频点选择模块； 所述时频变换模块设置成将接收到的时域信 号转换为频域信号； 所述频点选择模块设置成通过扫描待扫描频带的频域信 号的功率谱确定用于接入网络的频点。
时频变换模块可设置成通过如下方式将接收到的时域信号转换为频域信 号： 以参考时长 T为时间间隔将时域信号分为多个时域段信号， 该多个时域 段信号中的每一个至少包括一个完整的下行子帧或者时隙； 依次对各时域段 信号进行时频信号变换， 或者只对每个时域段内信号强度大于预设门限的部 分进行时频信号变换。
频点选择模块可设置成通过如下方式确定用于接入网络的频点： 对待扫 描频带的频域信号的功率谱进行扫描， 确定有效频段， 其中， 有效频段中包 含连续的频点并且每个频点对应的功率值均大于预设的功率门限； 将有效频 段中频点作为用于接入网络的备选频点。 该频点选择模块可设置成将有效频 段中与有效频段的中心频点的距离小于预设间隔门限的频点作为优先备选频 点， 将有效频段中除优先备选频点之外的其它频点作为次优先备选频点， 并 根据离中心频点的距离从近到远的顺序设置各优先备选频点的优先级。 本发明针对 LTE系统的特点， 釆用频语检测的方式， 将整个被测带宽内 的时域信号变换到频域信号， 然后对接收信号的频谱进行扫描， 确定可能的 中心频点， 优先进行检测。 本发明可以提高频率扫描的速度， 减少频率扫描 所需要的时间， 从而达到快速开机的效果， 并且降低移动终端接收机的功耗。
附图概述
图 1是实施例中实现快速频率扫描的移动终端的组成结构图；
图 2是实施例中实现快速频率扫描的方法示意图。
本发明的较佳实施方式
如图 1所示， 移动终端包括时频变换模块和频点选择模块。
时频变换模块设置成将接收到的时域信号转换为频域信号； 频点选择模块设置成通过扫描待扫描频带的频域信号的功率谱确定用于 接入网络的频点。
时频变换模块可设置成： 以参考时长 T为时间间隔将时域信号分为多个 时域段信号， 其中每个时域段信号至少包括一个完整的下行子帧或者时隙； 依次对各时域段信号进行时频信号变换， 或者只对每个时域段内信号强度大 于预设门限的部分进行时频信号变换。
时频变换模块可设置成通过如下方式对时域段信号进行时频信号变换： 以移动终端支持的最大傅利叶变换点数为单位对一时域段信号的釆样点进行 多次傅利叶变换后， 将得到的傅利叶变换结果进行非相干累加后作为该时域 段信号对应的频域信号。
时频变换模块还设置成在待扫描频带的带宽大于所述移动终端支持的最 大带宽时， 以所支持的最大带宽为单位带宽， 将多个单位带宽的频域信号依 次拼接成待扫描频带的频域信号。
频点选择模块可设置成通过对待扫描频带的频域信号的功率谱进行扫 描， 确定有效频段， 其中， 有效频段中包含连续的频点并且每个频点对应的 功率值均大于预设的功率门限， 将有效频段中频点作为用于接入网络的备选 频点。
频点选择模块还可设置成： 将有效频段中与有效频段的中心频点的距离 小于预设间隔门限的频点作为优先备选频点， 将有效频段中其它频点作为次 优先备选频点； 根据离中心频点的距离从近到远的顺序设置各优先备选频点 的优先级。
如图 2所示， 实现快速频率扫描的方法包括：
步骤 201 , 移动终端将接收到的时域信号转换为频域信号；
步骤 202 , 通过扫描待扫描频带的频域信号的功率谱确定用于接入网络 的频点。
步骤 201 中移动终端将接收到的时域信号转换为频域信号的过程还可以 使用以下技术手段：
移动终端将接收到的时域信号转换为频域信号时一般使用快速傅里叶变 换（FFT ) 的方式， 支持 LTE系统的移动终端具有 FFT模块， 无需增加新的 硬件设备。
移动终端以参考时长 T为时间间隔将时域信号分为多个时域段信号， 依 次对各时域段信号进行处理， 以移动终端支持的最大 FFT点数为单位对每段 时域段信号釆样点进行多次 FFT变换后， 将得到 FFT结果进行非相干累加后 作为此时域段信号对应的频域信号。进行此操作的原因是考虑到 TDD系统 (例 如 LTE-TDD), 移动终端在进行频率扫描的时候并不知晓此系统的上下行资 源配置， 为了确保能够检测到下行信号， 此参考时长 T不能太短。 在参考时 长 T内， 移动终端对时域信号釆样后得到的釆样点较多， 而通常接收机不能 支持做很大点数的 FFT, 例如移动终端支持的最大 FFT点数为 2048。 例如以 LTE-TDD为例， LTE-TDD中每 5ms至少会包含一个下行子帧， 一般设 T至 少为 5ms。 以 T设置为 10ms为例， 移动终端接收机以 30.72M的釆样率， 在 T时间段时获得 307200个釆样点， 而接收机最多做支持 2048点 FFT, 所以 可以连续做 2048点的 FFT, 然后将得到的信号进行非相干累加后作为此时域 段信号对应的频域信号。 例如非相干累加的方式可以为：
Figure imgf000007_0001
其中 r(n)为接收信号， L为进行 FFT变换的次数， R为接收信号的功率谱。 考虑移动终端在 LTE-TDD系统的上行时隙部分检测不到信号，可以为时 域段信号设置一个预设门限， 移动终端只对该时域段信号内信号强度大于预 设门限的部分进行时频信号变换， 转换方式同上。 对于时域段内信号强度小 于或等于预设门限的部分则不需要进行时频信号变换， 从而提高频率扫描效 率并且节省移动终端的功耗。
考虑到待扫描频带的带宽大于移动终端支持的最大带宽的情况， 例如 LTE的最大频带为 100MHz, 而接收机的有效带宽 18MHz, 移动终端以所支 持的最大带宽为单位带宽， 将多个单位带宽的频域信号依次拼接成待扫描频 带的频域信号。
通过步骤 201 可以得到待扫描频带内信号的功率谱。 上述方法以扫描 100MHz的频带为例，假定移动终端接收机的最大带宽为 18MHz,只需要 30ms 的时间就可以完成对 100MHz频带的扫描，远远小于传统的时域 RSSI检测方 法。
步骤 202中通过扫描待扫描频带的频域信号的功率谱确定用于接入网络 的频点的方法可以使用以下技术手段：
移动终端对待扫描频带的频域信号的功率谱进行扫描， 确定有效频段， 其中， 有效频段中包含连续的频点并且每个频点对应的功率值均大于预设的 功率门限， 此功率门限可以是一绝对门限， 也可以是根据信道的平均功率设 置的相对门限。
为了提高检测效率， 可以设置带宽门限， 移动终端获得的有效频段的带 宽小于此带宽门限时， 将此有效频段更新为无效带宽。 此带宽门限可以设为 1.4MHz, 为了减少漏检概率还可以设为 1MHz, 还可以根据性能要求对此带 宽门限的值进行不同的设置。
移动终端对频域信号的功率谱进行检测时按照一定的带宽进行检测， 带 宽可以从 100kHz-1.4MHz。 由于 1.4M带宽下的载波间隔为 320kHz左右， 所 以 300kHz是个较优的选择。
移动终端将有效频段中频点作为用于接入网络的备选频点。 可以将有效 频段中所有频点作为备选频点， 还可以将有效频段中与有效频段的中心频点 的距离小于预设间隔门限的频点作为优先备选频点， 将有效频段中其它频点 作为次优先备选频点， 根据离中心频点的距离从近到远的顺序设置各优先备 选频点的优先级。 优先备选频点的优先级从高到低的顺序对应于离中心频点 的从近到远的距离， 即离中以频点越近的优先备选频点的优先级越高。
移动终端检测备选频点时， 先检测优先备选频点， 再检测次优先备选频 点， 检测优先备选频时， 按照优先级从高到低的顺序检测， 在某一频点上检 测到满足 RSSI条件的信号时， 将此频点确定为接入网络的频点。
本发明的核心思想是对信号的频谱进行检测， 并根据频谱确定可能的中 心频点。 相比传统的直接利用时域信号 RSSI的方法， 可以提高扫频速度， 缩 短开机时间， 降低功耗。 当然， 本发明还可有其他多种实施例， 在不背离本发明精神及其实质的 但这些相应的改变和变形都应属于本发明所附的权利要求的保护范围。
本领域普通技术人员可以理解上述方法中的全部或部分步骤可通过程序 来指示相关硬件完成， 所述程序可以存储于计算机可读存储介质中， 如只读 存储器、 磁盘或光盘等。 可选地， 上述实施例的全部或部分步骤也可以使用 一个或多个集成电路来实现。 相应地， 上述实施例中的各模块或单元可以釆 用硬件的形式实现， 也可以釆用软件功能模块的形式实现。 本发明不限制于 任何特定形式的硬件和软件的结合。
工业实用性
与现有技术相比， 本发明可以提高频率扫描的速度， 减少频率扫描所需 要的时间， 从而达到快速开机的效果， 并且降低移动终端接收机的功耗。

Claims

权 利 要 求 书
1、 一种实现快速频率扫描的方法， 包括：
移动终端将接收到的时域信号转换为频域信号， 通过扫描待扫描频带的 频域信号的功率谱确定用于接入网络的频点。
2、如权利要求 1所述的方法， 其在将接收到的时域信号转换为频域信号 的步骤之前， 还包括：
所述移动终端以参考时长 T为时间间隔将接收到的时域信号分为多个时 域段信号， 其中每个时域段信号至少包括一个完整的下行子帧或者时隙。
3、 如权利要求 2所述的方法， 其中， 移动终端将接收到的时域信号转 换为频域信号的步骤包括：
所述移动终端将所述多个时域段信号依次转换为频域信号， 或者， 所述 移动终端只将每个时域段信号内信号强度大于预设门限的部分转换为频域信 号。
4、 如权利要求 3所述的方法， 其中，
所述移动终端在将一时域段信号转换为频域信号时， 以该移动终端支持 的最大傅利叶变换点数为单位对该时域段信号的釆样点进行多次傅利叶变 换， 将得到的傅利叶变换结果进行非相干累加， 将累加结果作为该时域段信 号对应的频域信号。
5、 如权利要求 1所述的方法， 还包括：
当待扫描频带的带宽大于所述移动终端支持的最大带宽时， 所述移动终 端以所支持的最大带宽为单位带宽， 将多个单位带宽的频域信号依次拼接成 待扫描频带的频域信号。
6、 如权利要求 1所述的方法， 其中， 通过扫描待扫描频带的频域信号的 功率谱确定用于接入网络的频点的步骤包括：
所述移动终端对待扫描频带的频域信号的功率谱进行扫描， 确定有效频 段， 其中， 有效频段中包含连续的频点并且每个频点对应的功率值均大于预 设的功率门限；
7、 如权利要求 6所述的方法， 其中， 所述移动终端将确定的有效频段中 的频点作为用于接入网络的备选频点的步骤包括：
所述移动终端将有效频段中与有效频段的中心频点的距离小于预设间隔 门限的频点作为优先备选频点， 将有效频段中除所述优先备选频点之外的其 它频点作为次优先备选频点； 根据离中心频点的距离从近到远的顺序设置各 优先备选频点的优先级。
8、 一种实现快速频率扫描的移动终端， 其特征在于， 所述移动终端包括 时频变换模块和频点选择模块； 其中，
所述时频变换模块设置成将接收到的时域信号转换为频域信号； 所述频点选择模块设置成通过扫描待扫描频带的频域信号的功率谱确定 用于接入网络的频点。
9、 如权利要求 8所述的移动终端， 其中， 所述时频变换模块是设置成通 过如下方式将接收到的时域信号转换为频域信号： 以参考时长 T为时间间隔 将时域信号分为多个时域段信号， 所述多个时域段信号中的每一个至少包括 一个完整的下行子帧或者时隙； 依次将各时域段信号转换为频域信号， 或者， 只将每个时域段信号内信号强度大于预设门限的部分转换为频域信号。
10、 如权利要求 8所述的移动终端， 其中， 所述频点选择模块是设置成 通过如下方式确定用于接入网络的频点： 对待扫描频带的频域信号的功率谱 进行扫描， 确定有效频段， 其中， 有效频段中包含连续的频点并且每个频点 对应的功率值均大于预设的功率门限；
将有效频段中的频点作为用于接入网络的备选频点。
11、 如权利要求 10所述的移动终端， 其中， 所述频点选择模块是设置成 通过如下方式将有效频段中的频点作为用于接入网络的备选频点：
将有效频段中与有效频段的中心频点的距离小于预设间隔门限的频点作 为优先备选频点， 将有效频段中除所述优先备选频点之外的其它频点作为次 优先备选频点， 并根据离中心频点的距离从近到远的顺序设置各优先备选频 点的优先级。
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102665256A (zh) * 2012-04-06 2012-09-12 华为技术有限公司 无线通信系统扫频方法与装置、搜网方法与终端

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104469892B (zh) * 2013-09-25 2019-08-06 锐迪科（重庆）微电子科技有限公司 频域频点盲搜方法、系统和移动终端
CN104202097B (zh) * 2014-08-07 2016-08-17 安徽白鹭电子科技有限公司 一种用于数字监测接收机的高速扫描方法
CN104618284B (zh) * 2014-12-29 2018-09-11 大唐移动通信设备有限公司 一种数字预失真处理方法和装置
CN106413042B (zh) * 2015-07-31 2020-12-08 展讯通信（上海）有限公司 用户终端及其频点搜索方法
CN106488476B (zh) * 2015-08-31 2020-07-31 展讯通信（上海）有限公司 多模终端功率扫描的方法及多模终端
CN106226799A (zh) * 2016-07-30 2016-12-14 杨超坤 一种实现快速频率扫描的移动终端
CN108112056B (zh) * 2016-11-24 2020-09-22 联芯科技有限公司 用户终端的扫频方法与装置
CN108235408A (zh) * 2018-02-23 2018-06-29 青岛海信移动通信技术股份有限公司 一种搜网方法、装置及终端
WO2020191525A1 (zh) * 2019-03-22 2020-10-01 华为技术有限公司 小区搜索的方法和装置
CN112134599B (zh) * 2020-09-17 2021-08-17 展讯通信（上海）有限公司 扫频的方法、设备、装置及存储介质

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007135640A2 (en) * 2006-05-18 2007-11-29 Koninklijke Philips Electronics, N.V. Method and system for detecting narrowband signals using a receiver with a wideband frontend
CN101251390A (zh) * 2008-04-10 2008-08-27 中国科学院长春光学精密机械与物理研究所 一种基于时频变换的微弱信号检测装置
CN101375175A (zh) * 2006-01-26 2009-02-25 高通股份有限公司 用于方位定位接收器的交叉相关抑制技术
CN101600254A (zh) * 2008-06-06 2009-12-09 华为技术有限公司 多频点系统中的终端接入方法、系统和设备

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004010719A1 (en) * 2002-07-24 2004-01-29 Motorola, Inc., A Corporation Of The State Of Delaware Method and apparatus for acquiring a carrier frequency in a cdma communication system
CN100391285C (zh) * 2005-04-30 2008-05-28 大唐移动通信设备有限公司 一种移动通信终端的小区搜索方法及其装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101375175A (zh) * 2006-01-26 2009-02-25 高通股份有限公司 用于方位定位接收器的交叉相关抑制技术
WO2007135640A2 (en) * 2006-05-18 2007-11-29 Koninklijke Philips Electronics, N.V. Method and system for detecting narrowband signals using a receiver with a wideband frontend
CN101251390A (zh) * 2008-04-10 2008-08-27 中国科学院长春光学精密机械与物理研究所 一种基于时频变换的微弱信号检测装置
CN101600254A (zh) * 2008-06-06 2009-12-09 华为技术有限公司 多频点系统中的终端接入方法、系统和设备

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102665256A (zh) * 2012-04-06 2012-09-12 华为技术有限公司 无线通信系统扫频方法与装置、搜网方法与终端
CN102665256B (zh) * 2012-04-06 2015-04-29 华为技术有限公司 无线通信系统扫频方法与装置、搜网方法与终端

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