WO2005064833A1 - Procede de recherche de trajets multiples d'un systeme avec acces multiple a repartition par code - Google Patents

Procede de recherche de trajets multiples d'un systeme avec acces multiple a repartition par code Download PDF

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Publication number
WO2005064833A1
WO2005064833A1 PCT/CN2003/001129 CN0301129W WO2005064833A1 WO 2005064833 A1 WO2005064833 A1 WO 2005064833A1 CN 0301129 W CN0301129 W CN 0301129W WO 2005064833 A1 WO2005064833 A1 WO 2005064833A1
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Prior art keywords
multipath
energy
peak
delay
division multiple
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PCT/CN2003/001129
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English (en)
French (fr)
Inventor
Jiewei Ding
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Zte Corporation
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Application filed by Zte Corporation filed Critical Zte Corporation
Priority to AU2003296211A priority Critical patent/AU2003296211A1/en
Priority to DE60324613T priority patent/DE60324613D1/de
Priority to ES03785469T priority patent/ES2315553T3/es
Priority to CN2003801106855A priority patent/CN1879338B/zh
Priority to AT03785469T priority patent/ATE413740T1/de
Priority to EP03785469A priority patent/EP1699154B8/en
Priority to PCT/CN2003/001129 priority patent/WO2005064833A1/zh
Publication of WO2005064833A1 publication Critical patent/WO2005064833A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7073—Synchronisation aspects
    • H04B1/7075—Synchronisation aspects with code phase acquisition
    • H04B1/7077—Multi-step acquisition, e.g. multi-dwell, coarse-fine or validation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7073—Synchronisation aspects
    • H04B1/7075—Synchronisation aspects with code phase acquisition
    • H04B1/70755—Setting of lock conditions, e.g. threshold
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7073—Synchronisation aspects
    • H04B1/7075—Synchronisation aspects with code phase acquisition
    • H04B1/70757—Synchronisation aspects with code phase acquisition with increased resolution, i.e. higher than half a chip
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7097—Interference-related aspects
    • H04B1/711—Interference-related aspects the interference being multi-path interference
    • H04B1/7113—Determination of path profile
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7097—Interference-related aspects
    • H04B1/711—Interference-related aspects the interference being multi-path interference
    • H04B1/7115—Constructive combining of multi-path signals, i.e. RAKE receivers
    • H04B1/7117—Selection, re-selection, allocation or re-allocation of paths to fingers, e.g. timing offset control of allocated fingers

Definitions

  • the present invention relates to a signal receiving technology in a Code-Division Multiple Access (Code-Division Mul t iple-Access, CDMA for short) communication system. Specifically, the present invention relates to a multipath search method in a signal receiving process. The present invention is applicable to any Communication system of code division multiple access technology.
  • Code-Division Mul t iple-Access CDMA for short
  • Code division multiple access is a multiple-access method based on spread-spectrum technology. In recent years, it has become a multiple-access method applied to communication systems in addition to frequency-division multiple-access FDMA and day-division multiple-access TDMA technologies. Compared with frequency division multiple access and time division multiple access technologies, 0) MA technology has many advantages, such as high frequency utilization, simple planning and so on.
  • the communication systems using CDMA technology are mainly: narrow-band CDMA system, namely IS-95 system, wide-band CDMA system, namely WCDMA system, Cdnm2000 system, TD-SCDMA system, and TD-CDMA system.
  • Shangyi communication systems all adopt multi-code spread spectrum technology, also called double-layer spread spectrum code distribution technology.
  • the method of spreading the reverse link from the mobile user to the base station can be divided into two steps.
  • the first step is to use an orthogonal function (such as Walsh function, 0VSF code, etc.) with zero cross-correlation when the delays are aligned.
  • the channel code is used to spread the signal.
  • This step can be referred to as spreading, and the recovery process corresponding to the receiving end (base station) is called despreading.
  • the second step is to perform the auto-correlation and cross-correlation performance uniquely assigned by each user. Multiply the pseudo-random code (such as PN sequence, M-sequence, Gold sequence, etc.) with the signal.
  • pseudo-random code such as PN sequence, M-sequence, Gold sequence, etc.
  • This step can be called scrambling, and the reversal process corresponding to the receiving end (base station) is called descrambling.
  • Scrambling code In this step, scrambling codes are used to distinguish different mobile users. A value in the scrambling sequence is also called a chip.
  • the spreading method of the forward link from the base station to the mobile user is also divided into the same two steps. The only difference is that in the forward link, the base station or cell is distinguished by a scrambling code. The scrambling code of the base station or cell is different. In a general mobile communication system, signals between a base station and a mobile station propagate along several paths between a receiver and a transmitter.
  • This multipath propagation phenomenon is mainly caused by the reflection of signals on the surface of objects around the transmitter and receiver. Due to different propagation paths, the propagation delays of different multipath components of the same signal reaching the receiver along different paths to the receiver are also different, thereby causing multipath interference and signal fading.
  • the receiver in a CDMA system is a receiver with a multi-branch structure.
  • Each branch is a separate receiver element.
  • the function of the receiver is to demodulate the desired received signal component and combine the signals of different receiver elements, which can improve The quality of the received signal.
  • Each branch is synchronized with multipath with substantially the same propagation delay.
  • This receiver is also called a Rake receiver, and can superimpose the multipath energy of different delays of the same user according to a certain rule, thereby improving the receiving performance.
  • the synchronization of the local spreading code and the spreading code in the received signal is the prerequisite for normal communication of the CDMA system. If code synchronization cannot be achieved, it cannot be correctly despread, and the original information cannot be correctly solved. The more accurate the code synchronization, the better the demodulation performance of the receiver.
  • Multipath search is to detect the propagation delay of the multipath signal from the received signal, and adjust the local spreading code according to the propagation delay to keep it synchronized with the spreading code of each multipath information in the received signal. If the multipath search cannot accurately find the multipath delay, the demodulation performance of the subsequent Rake receiver will be lost.
  • a scrambling code is used to perform sliding correlation integration with a received signal to obtain a complex correlation function (CRF) of a desired user signal, and then the real part of the complex correlation function CRF is taken And the sum of squares of the imaginary part to obtain a power delay function (PDP), that is, the power delay function PDP is the square of the modulus value of the correlation function between the scrambling code and the received signal.
  • PDP power delay function
  • multipath search is equivalent to descrambling different delays in the received signal.
  • Choosing the true multipath delay usually requires angle scrambling of hundreds of delay positions.
  • the radial positions are just a few of them, generally less than 10 positions.
  • Subsequent Rake receivers only need to demodulate the selected true multipath position.
  • the wireless communication environment is constantly changing, and it is necessary to continuously perform multi-path search to reflect the current channel environment in time.
  • a parallel search method is also adopted. Therefore, in the receiver, the calculation amount of multipath search accounts for a large proportion, and its implementation is also relatively complicated. If the calculation amount of multipath search is reduced, the accuracy of the corresponding multipath search is generally low, and its adjacent delay point is usually equal to half a chip period, that is, the accuracy is only 1/2 chip, and demodulation needs The accuracy is often 1/4 chip or even 1/8 chip. In order to improve the accuracy, the so-called late-morning gate tracking method is usually used.
  • the demodulation of the signal energy at the multipath delay (called the middle path) is performed while demodulating the multipath delay.
  • the signal energy of the early half chip (referred to as the early path) and the latter half chip (referred to as the late path or the late path), and then the signals of the early, middle, and late three paths are compared. If the signal energy of the late path exceeds a certain threshold , Slide the multipath delay position of the three paths in the morning, middle, and evening to the direction of the evening path by 1/8 or 1/4 chip. If the signal energy of the early path exceeds a certain threshold, then multipath time If the signal energy of the two channels is similar in the morning and evening, the current multipath delay position is considered to be accurate, and no sliding is necessary.
  • This process is called sooner or later door tracking, and this method Further fine-tuning is essentially similar to a searcher with a small search window (only three delay positions).
  • the multipath allocation method usually needs to synthesize the results of the multipath search and the results of the door tracking sooner or later, and select an appropriate multipath from the two to allocate to Rake.
  • Receiver Sooner or later door tracking methods also increase the complexity of multipath allocation management methods.
  • a more detailed description of the sooner or later door tracking method is provided in ((CDMA: Pr inciples of Spread Spectrum Commimication) (Addison-WeSley Publishing Company, by Andrew J. Viterbi).
  • the multi-path search method can only provide a search with poor accuracy.
  • a sooner or later door tracking method is used, but the method is complicated.
  • the technical problem to be solved by the present invention is to provide a code division multiple access communication system and a unified multipath search method, so as to overcome the shortcomings of the complex implementation of the gate tracking method sooner or later, so that the multipath search method does not substantially increase the computational complexity. Under the premise, the accuracy of the multipath search results is improved, and the complexity of the Rake receiver is greatly simplified.
  • the multipath search method of the present invention first calculates a power delay function for a received signal, selects a plurality of peaks with larger energy, and then performs threshold comparison interpolation on the selected peaks to determine the multipath delay position and energy, and finally according to The interpolation results determine the multipath delay.
  • the step of calculating a power delay function further includes: performing a matching correlation operation using a local scrambling code and a received signal to obtain a correlation function, calculating a square of a modulus value of the correlation function, and obtaining a power delay function.
  • the threshold comparison interpolation step further includes: calculating energy of a delay position before and after the selected peak The ratio of the difference to the selected peak energy; compare the above ratio with a threshold to determine the real number segment where the ratio is located, and then determine the multipath delay position and multipath energy corresponding to the peak based on the value of the real number segment; repeat the above Step, complete the threshold comparison interpolation operation for all selected peaks.
  • the step of determining the multipath delay further includes: selecting a multipath with a larger energy among the multipaths obtained through the threshold comparison interpolation step, and the corresponding delay is the multipath delay.
  • the multi-path search method of the present invention can greatly improve the multi-path search accuracy under the condition that the calculation complexity is basically unchanged, and the search accuracy can reach I / 4 chip accuracy. 1, 1/8 chip accuracy, and even 1/16 chip accuracy.
  • the method of the present invention does not need to use a sooner or later door tracking module, nor does it need a complicated tracking algorithm, which greatly simplifies the implementation complexity of the Rake receiver and the complexity of multipath allocation management.
  • the method of the invention is applicable to base stations and mobile stations of various code division multiple access communication systems. BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a schematic structural diagram of a typical CDMA system
  • FIG. 2 is a schematic structural diagram of a CDMA system using the multipath search method of the present invention
  • FIG. 3 is a flowchart of a multi-path search method according to the present invention.
  • Figure 4 is a schematic diagram of an ideal multipath peak shape
  • 5 is a schematic diagram showing the relationship between the deviation of the true peak position and the search peak position and the ratio of the energy difference between the sampling points before and after the search peak to the search peak energy;
  • FIG. 6 is a schematic diagram showing the relationship between the energy deviation factors of the true peak and the search peak, and the ratio of the energy difference between the sampling points before and after the search peak and the search peak energy.
  • FIG. 1 is a block diagram of a typical CDMA system in the prior art.
  • the signal source 101, the transmission filter 102, the radio frequency modulation module 103, and the antenna 104 form a transmitting end device.
  • a baseband transmission filter 102 also known as a pulse shaping filter.
  • the digital signal is converted into a signal suitable for radio frequency modulation, and then modulated by the radio frequency modulation module 103, and finally the signal is sent out through the antenna 104.
  • the characteristics of the transmission filter 102 are generally fixed. For example, for a mobile station of the WC-La system, this filter is a root-raised cosine filter with a roll-off coefficient of 0.22.
  • the receiving end includes an antenna 105, a radio frequency channel 106, a multipath search module 107, a multipath management module 108, and a Rake receiver.
  • the antenna 105 enters the multi-path search module 107 through the radio frequency channel 106, and executes the multi-path search process.
  • the other signal output by the radio frequency channel 106 directly enters the Rake receiver.
  • the multi-path search module uses the existing multi-path search method, such as a multi-path search sooner or later, and outputs the multi-path delay to the multi-path management module 108, and then enters the Rake receiver.
  • the Rake receiver is composed of a plurality of relatively independent receiver elements 109.
  • Each receiver element 109 includes a delay adjustment module 1091, an early demodulation module 1092, a middle demodulation module 1093, and a late demodulation module 1094.
  • the delay adjustment module 1091 receives signals from the multipath management module 108 and the radio frequency channel 106, performs delay adjustment, and outputs the signals to the early demodulation module 1092, the middle demodulation module 1093, and the late demodulation module 1094.
  • the demodulation results of the three-way demodulation module in the morning, middle, and night need to be fed back to the delay adjustment module 1091 to form a feedback loop.
  • the delay adjustment module 1091 also needs to receive the information from the multipath management module 108, and feed back the delay adjustment information to the multipath management module 108, which also forms a feedback loop. And the feedback loop will complicate the method of multipath search.
  • FIG. 2 is a structural diagram of a CDMA system using the multipath search method of the present invention.
  • the signal source 101, the transmission filter 102, the radio frequency modulation module 103, and the antenna 104 constitute a transmitting end device.
  • the receiving end includes an antenna 105, a radio frequency channel 106, a multipath search module 207, and a Rake receiver.
  • the antenna 105 enters the multipath search module 207 through the radio frequency channel 106.
  • the multipath search module 207 uses the method of the present invention to perform multipath search, and outputs the searched multipath delay to the Rake receiver.
  • the other signal output from the radio frequency channel 106 directly enters the Rake receiver.
  • the Rake receiver includes a plurality of relatively independent receiver elements 209, where each receiver element includes only a midway demodulation module 2091.
  • the structure of the Rake receiver element is greatly simplified, the delay adjustment module, the early demodulation module and the late demodulation module are removed, and the middle demodulation module 2091 is exactly the same as the original mid demodulation module 1093.
  • a complex multipath management module is not required in the system at the receiving end.
  • the feedback loop is not included in the system at the receiving end, and the system is greatly simplified.
  • the core idea of the multipath search method of the present invention is: without changing the accuracy of the multipath search correlation, calculating the power delay function PDP, and then performing threshold decision-based interpolation on the peak data with larger energy in the power delay function PDP, Specifically, the ratio of the difference between the energy of the sampling points before and after the peak and the peak energy is calculated, and then this ratio is compared with a set threshold to calculate a more accurate multipath delay position and energy.
  • the peaks described here and below are defined as locations where the energy on both sides is less than the current (middle) energy.
  • the flowchart is shown in Figure 3.
  • the present invention is an interpolation method based on threshold decision, so it is necessary to set the threshold, and the threshold setting can be completed in the system configuration stage, as shown in block 301.
  • the number of thresholds, the thresholds and their corresponding delay position deviations and energy deviations are determined.
  • the 2N threshold divides the real number into 2N + 1 real number segments, and sequentially defines the segment numbers of the real number segments as:-N, -N + 1,..., 0, 1,..., N. If the ratio R calculated in the threshold interpolation operation of the current peak is in the real number segment between the threshold Th (-1) and Th (1), that is, the real number segment 0, then the current peak position can be considered as the position of the true multipath delay.
  • the current peak energy is the true multipath energy.
  • the position deviation corresponding to the true multipath is DeltaOffset (a)
  • the delay position is generally in units of 0.5 chips.
  • the calculated ratio R is a real number segment between the threshold Th (1) and Th (2), that is, the real number segment 1, the position of the real peak is the current peak position plus DeltaOffset (1 ),
  • the energy of the real peak is the energy of the current peak multiplied by AlphaEnergy (1).
  • DeltaOf f set ( ⁇ 1) — 0 ⁇ 125 chips
  • DeltaOffset (1) + 0.125 chips
  • DeltaOf f set (2) +0.25 chips.
  • DeltaOffset (1) +0.25 chips.
  • a specific multipath search method based on threshold interpolation is executed during the system operation phase, and the power delay function PDP is first calculated (block 302).
  • This is a basic step of multipath search.
  • the integration length used may be different. The effect of different integration lengths on the method of the invention is minimal.
  • a local scrambling code and a received signal are used to perform a matching correlation operation to obtain a correlation function, and then the square of the modulus value of the correlation function, that is, the sum of the squares of the real part and the imaginary part, is obtained to obtain power values with different delays.
  • a threshold interpolation operation is performed (block 303).
  • the energy path is determined or calculated by the system.
  • the maximum number of Mpaths that exceed the energy threshold is selected.
  • the value of Mpath can be determined by The system makes or calculates it by itself. Typically, the value of Mpath ranges from 4 to 16.
  • the ratio R [PDP (k- 1 )-PDP (k + 1)] / PDP (k).
  • the ratio R Compare the ratio R with a set threshold to determine the real number segment where the ratio R is located, and then determine the true multipath delay position and the corresponding multipath energy according to the value of the real number segment. If the real number segment where the ratio R is located is p, then the delay position of the true multipath is the selected peak plus the position offset of the real number segment where the ratio R is located. Delta Offset (p), and its multipath energy is PDP (k ) ⁇ AlphaEnergy (p X Threshold comparison interpolation is performed on all selected peaks according to the above steps to obtain the corresponding true multipath delay position and multipath energy.
  • Multipath delay is finally determined (block 304).
  • M multipaths are selected according to the energy from large to small.
  • the specific value of M can be determined by each system.
  • Figure 4 is a schematic diagram of the shape of an ideal multipath peak. This ideal peak is obtained with 256 chips as the coherent integration length and sampling accuracy of 1/8 chip. The true peak position of the multipath is 15 and the real energy of the multipath is about 4600. If other integration lengths are used, the resulting peak shape will be different. In this embodiment, a coherent integration length of 256 chips is used as an example for description.
  • FIG. 5 is the relationship between the deviation between the true peak position and the search peak position, and the ratio of the energy difference between the sampling points before and after the search peak to the search peak energy.
  • the sampling point position is to select one point from every four adjacent points in the curve in FIG. 4. such, The position 15 of the true peak may not be selected, and thus, the position of the search peak may deviate from the position of the true peak.
  • the position deviation value and the search peak have the following characteristics: The larger the absolute value of the position deviation, the greater the absolute value of the ratio R of the energy difference between the two sampling points before and after the search peak and the peak energy, and the sign of the ratio corresponds to the direction of deviation.
  • 4 thresholds can be defined according to the curve in Figure 5, which are -0.68, -0.21, 0.21, and 0.68, corresponding to the four delay positions.
  • the deviations DeltaOffset are -0.25, -0.125, 0.125, and 0.25.
  • Figure 6 shows the relationship between the energy deviation factors of the real peak and the search peak, and the ratio of the energy difference between the sampling points before and after the search peak to the energy of the search peak.
  • the sampling point position is to select one point from every four adjacent points in the curve in FIG. 4.
  • the position 15 of the true peak may not be obtained, and the energy of the search peak may be lower than the energy of the true peak.
  • the energy deviation and the search peak have the following characteristics: The larger the absolute value of the energy deviation, the larger the absolute value of the ratio R between the energy difference between the two sampling points before and after the search peak and the peak energy.
  • the specific relationship is shown in the curve in Figure 6.
  • the energy difference is 0, and the ratio R is 0.
  • the ratio R is 0.43
  • the true peak energy is 1.28 times the search peak energy, and the ratio R is 0.94.
  • 4 thresholds can be defined according to the curve of Figure 5, which are -0.68, -0.21, 0.21, and 0.68, respectively, corresponding to 4 delays.
  • the position deviation DeltaOffset is-0.25, -0.125, 0.125, and 0.25, and the ratio of real energy to search energy is AlphaEnergy of 1.28, 1.06, 1.06, and 1.28. From the above analysis, it can be known that, in this embodiment, the energy deviation factor AlphaEnergy only needs to retain two data, and among the four values of the delay position deviation Delta Offset and the threshold Th, if the sign is not considered, it is only two. Different sizes of data, which brings convenience for specific implementation.
  • the CDMA receiving system applying the multi-path search method of the present invention can greatly reduce the complexity of the receiving system without reducing performance, and the implementation is simple and the effect is obvious. Suitable for various code division multiple access communication systems.

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  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)
  • Error Detection And Correction (AREA)
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Description

码分多址通信系统的多径搜索方法 技术领域
本 明涉及码分多址 ( Code-Divis ion Mul t iple-Access , 简称 CDMA )通 信系统中的信号接收技术， 具体地说， 涉及信号接收过程中的多径搜索方法， 本发明适用于任何采用码分多址技术的通讯系统。
背景技术
码分多址是一种基于扩频技术的多址接入方法， 近年来已成为除频分多址 FDMA和日寸分多址 TDMA技术之外又一种应用于通信系统的多址方法。 与频分多 址和时分多址技术相比， 0)MA技术具有许多优点， 例如频 i瞽利用率高、 规划筒 单等。 目前采用 CDMA技术的通信系统主要有： 窄带 CDMA系统即 IS- 95系统、 宽带 CDMA系统即 WCDMA系统、 Cdnm2000系统、 TD- SCDMA系统以及 TD- CDMA系 统等。
上逸通信系统都采用了多码扩频技术， 也称双层扩频码分配技术。 这样， 从移动用户到基站的反向链路的扩频方式可以分为两步， 第一步是采用时延对 齐时互相关为零的正交函数（如 Wal sh函数、 0VSF码等）作为信道码， 对信号 扩频， 该步骤可称为加扩， 对应接收端 （基站） 的恢复过程称为解扩； 第二步 是将每个用户唯一分配的自相关和互相关性能都比较好的伪随机码（如 PN序 列、 M序列、 Gold序列等）与信号相乘， 该步骤可称为加扰， 对应接收端 （基 站）的炙复过程称为解扰， 上述伪随机码称作扰码， 在该步骤中用扰码区分不 同的移动用户。 在扰码序列中的一个数值也叫码片 （chip )。 同样， 在这些系统 中， 从基站到移动用户的前向链路的扩频方式也分为同样的两步， 唯一的区别 是在前向链路中， 用扰码区分基站或小区， 不同的基站或小区的扰码不同。 在一般的移动通信系统中， 基站和移动台之间的信号沿接^:机和发射机之 间的若干路径进行传播。 这种多径传播现象主要是由信号在发射机和接收机周 围的物体表面的反射引起的。 由于传播路径不同， 同一信号沿不同路径到达接 收机的不同多径成分到达接收机的传播时延也不同， 从而造成多径干扰和信号 衰落。
CDMA系统中的接收机是一种多分支结构的接收机，每一个分支是一个单独 的接收机元件， 接收机的功能是解调期望的接收信号分量， 合并不同的接收机 元件信号， 可以改善接收信号的质量。 每一个分支与传播时延基本相同的多径 同步。 这种接收机也叫瑞克 （Rake )接收机， 能把同一用户不同时延的多径能 量按一定规则进行叠加， 从而提高接收性能。
本地扩频码与接收信号中扩频码的同步是 CDMA系统实现正常通信的前提。 如果不能实现码同步， 就无法正确解扩， 无法正确解出原始信息。 码同步越精 确， 接收机的解调性能就越好。 多径搜索就是从接收信号中检测出多径信号的 传播时延， 根据传播时延调整本地扩频码， 使之与接收信号中各多径信息的扩 频码保持同步。 如果多径搜索不能精确地搜索到多径时延， ^^么后面的 Rake 接收机的解调性能就会有损失。
在现有的多径搜索方法中， 首先用扰码与接收信号进行滑动相关积分， 得 到期望用户信号的复数相关函数 ( Complex Relat ion Funct ion, 筒称 CRF ), 然后取复数相关函数 CRF实部和虚部的平方和，得到功率时延函数（ Power Delay Prof i le, 简称 PDP )， 即功率时延函数 PDP是扰码与接收信号的相关函数的模 值平方。 然后从功率时延函数 PDP中找出函数值较大（即相关值较大、 功率较 大）或者函数值大于一定门限的峰值， 该峰值的位置就是多径时延的位置。 以 上是传统的多径搜索方法,在《现代移动通信系统》 (人民邮电出版社、祁玉生、 03001129 召 p世祥编著）、 《CDMA: Principles of Spread Spectrum Communication》 (Addison-WeSley Publishing Company, by Andrew J. Viterbi)、 《0ptimal Decision Strategies for Acquisition of Spread-Spectrum Signals in Frequency-Selective Fading Channels 》 (IEEE Transactions on communications Vol.46. No.5. , by Roland R. Rick and Laurence B. Mil stein. ) 等文献中都有叙述。
其实多径搜索就相当于对接收信号中各个不同的时延用扰码进行解扰， 选 择出真正的多径时延， 通常需要对数百个时延位置进行角竿扰， 而真正的多径位 置只是其中的几个， 一般少于 10个位置。 后续的 Rake接收机只需要对选择出 的真正的多径位置进行解调即可。
无线通信环境是不断变化的， 需要不断地进行多径搜索， 及时反映当前信 道环境。 为了减少多径搜索的时间， 还采用并行搜索的方法。 因此在接收机中， 多径搜索的运算量占很大比重， 其实现也比较复杂。 如果降低多径搜索的运算 量， 相应的多径搜索的精度一般也比较低， 其相邻时延点通常等于半个码片周 期， 也就是说精度只有 1/2码片， 而解调需要的精度往往是 1/4码片甚至 1/8 码片。 为了提高精度， 通常采用所谓的迟早门跟踪方法， 其方法是在 Rake接收 机的每个分支中， 解调多径时延处（称中路） 的信号能量的同时， 解调比多径 时延早半个码片 （称早路）和迟半个码片 （称迟路或晚路） 的信号能量， 然后 对早中晚三路的信号进行比较， 如果晚路的信号能量超过一定的门限， 则把早 中晚三路的多径时延位置向晚路方向滑动 1/8或 1/4码片， 如果早路的信号能 量超过一定门限， 则把早中晚三路的多径时延位置向早路方向滑动 1/8或 1/4 码片， 如果早晚两路的信号能量相差不多， 则认为当前的多径时延位置是比较 准确的， 不必进行滑动。 这个过程称为迟早门跟踪， 该方法对搜索结果进行了 进一步的精细调整， 其实质类似于一个搜索窗较小 （只有三个时延位置） 的搜 索器。 采用迟早门跟踪方法， 虽然使接收机的解调性能得到较大提高， 但同时 也使 Rake接收机的复杂度增加了一倍左右。 另外， 为了在多径分配时就分配比 较准确的时延位置， 多径分配方法通常需要综合多径搜索的绪果和迟早门跟踪 的结果， 从两者中选出合适的多径分配给 Rake接收机。 迟早门跟踪方法也增 加了多径分配管理方法的复杂度。 在 ((CDMA: Pr inciples of Spread Spectrum Commimicat ion》 (Addison-WeSley Publ ishing Company, by Andrew J. Vi terbi) 中对迟早门跟踪方法有较详细的描述。
综上， 在现有技术中， 多径搜索方法只能提供精度较差的搜索， 为了提高 精度， 采用了迟早门跟踪方法， 但该方法复杂度大。 发明内容
本发明所要解决的技术问题在于提供一种码分多址通信系、统的多径搜索方 法， 以克服迟早门跟踪方法实现复杂的缺点， 使多径搜索方 ^在基本不提高计 算复杂度的前提下提高多径搜索结果精度， 同时大大简化 Rake 接收机的复杂 度。
本发明所述多径搜索方法, 首先对接收信号计算功率时延函数， 选择其中 多个能量较大的峰值， 然后对选择的峰值进行门限比较插值， 确定多径时延位 置及能量， 最后根据插值结果确定多径时延。
所述计算功率时延函数步骤， 进一步包括： 用本地扰码和接收信号进行匹 配相关运算， 获得相关函数， 计算上述相关函数的模值平方， 得到功率时延函 数。
所述门限比较插值步骤， 进一步包括： 计算所选峰值前后时延位置的能量 之差与所选峰值能量的比值； 将上述比值与门限进行比较， 确定比值所处的实 数段， 然后根据实数段的值， 确定该峰值对应的多径时延位置及多径能量； 重 复上述步骤， 完成全部所选峰值的门限比较插值操作。
所述确定多径时延步骤进一步包括： 在经过所述门限比较插值步骤获得的 多径中， 选择其中多个能量较大的多径， 对应的时延就是多径时延。
本发明所述多径搜索方法， 与现有的多径搜索方法相比, 可以在保证计算 复杂度基本不变的情况下大幅度提高多径搜索精度， 搜索精度可以达到 I/4码 片精度、 1/8码片精度， 甚至达到 1/16码片精度。 同时， 本发明方法不需要采 用迟早门跟踪模块，也就不需要复杂的跟踪算法， 大大简化了 Rake接收机的实 现复杂度以及多径分配管理的复杂度。 本发明方法适用于各种码分多址通信系 统的基站和移动台。 附图说明
图 1是一种典型的 CDMA系统的结构示意图；
图 2是采用本发明多径搜索方法的 CDMA系统的结构示意图；
图 3是本发明多径搜索方法的流程图；
图 4是理想的多径峰值形状示意图；
图 5是真正峰值位置与搜索峰值位置的偏差与搜索峰值前后采样点能量差 与搜索峰值能量的比值的关系示意图；
图 6是真正峰值和搜索峰值的能量偏差因子与搜索峰值前后采样点能量差 与搜索峰值能量的比值的关系示意图。 具体实施方式 下面结合附图和实施例对本发明的技术方案做进一步的详细描述， 根据这 些附图， 本领域的普通技术人员可以很容易实现本发明。
图 1是现有的典型 CDMA系统的结构图。 信号源 101、 发射滤波器 102、 射 频调制模块 103和天线 104组成了发射端的装置， 信号在进行射频调制之前， 首先经过一个基带的发射滤波器 102 , 也称作脉沖成形滤波器， 把扩频后的数 字信号转换成适合射频调制的信号， 再经过射频调制模块 103调制， 最后通过 天线 104 将信号发送出去。 发射滤波器 102 的特性一般是固定的， 比如对于 WC丽 A系统的移动台， 这个滤波器是滚降系数为 0. 22的根升余弦滤波器。 在接 收端， 包括天线 105、 射频通道 106、 多径搜索模块 107、 多径管理模块 108和 Rake接收机。天线 105接收到信号后，通过射频通道 106进入多径搜索模块 107 , 执行多径搜索过程， 射频通道 106输出的另一路信号直接进入 Rake接收机中。 多径搜索模块采用现有的多径搜索方法， 如迟早门跟踪方法进行多径搜索， 并 输出多径时延到多径管理模块 108中， 再邊入 Rake接收机。 Rake接收机由多 个相对独立的接收机元件 109组成， 在每个接收机元件 109中都包含有时延调 整模块 1091、 早路解调模块 1092、 中路解调模块 1093和晚路解调模块 1094。 时延调整模块 1091接收来自多径管理模块 108和射频通道 106的信号，进行时 延调整，并输出给早路解调模块 1092、中路解调模块 1093和晚路解调模块 1094。 早中晚三路解调模块解调的结果需要反馈给时延调整模块 1091 , 构成一个反馈 环。 同时， 时延调整模块 1091还需要接收多径管理模块 108的信息， 并把时延 调整的信息反馈给多径管理模块 108， 也构成一个反馈环。 而反馈环都会使多 径搜索的方法变得复杂。
图 2是采用本发明多径搜索方法的 CDMA系统的结构图。 与图 1相同，信号 源 101、发射滤波器 102、射频调制模块 103和天线 104组成发射端的装置。 在 接收端， 则包括天线 105、 射频通道 106、 多径搜索模块 207和 Rake接收机。 天线 105接收信号后， 通过射频通道 106进入多径搜索模块 207 , 多径搜索模 块 207采用本发明的方法进行多径搜索，并将搜索的多径 ^延输出到 Rake接收 机。 射频通道 106输出的另一路信号直接进入 Rake接收机。 Rake接收机包括 多个相对独立的接收机元件 209 , 其中每个接收机元件只包含中路解调模块 2091。 与图 1相比， Rake接收机元件的结构大大简化， 去掉了时延调整模块、 早路解调模块和晚路解调模块，而且中路解调模块 2091与原来的中路解调模块 1093完全相同。采用本发明，在接收端的系统中也不需要复杂的多径管理模块。 与图 1相比， 接收端的系统中没有了反馈环， 系统大大简化。
本发明的多径搜索方法， 其核心思想是： 不改变多径搜索相关积分精度， 计算功率时延函数 PDP， 然后对功率时延函数 PDP中能量较大的峰值数据进行 基于门限判决的插值， 具体的说， 就是计算峰值前后采样点的能量之差与峰值 能量的比值， 然后用这个比值与设定的门限进行比较， 计算更精确的多径时延 位置和能量。 此处和下文中所述的峰值定义为两边能量比当前（中间） 能量小 的位置。 其流程图如图 3所示。
本发明是基于门限判决的插值方法， 那么有必要对门限进行设置， 对门限 的设置可以在系统配置阶段完成， 如方框 301所示。 根据系统搜索精度的要求 确定门限的个数、 门限值及其相应的时延位置偏差和能量偏差。 根据搜索精度 要求， 确定 2N个按大小顺序排列的门限 Th (n) , 其中 η = ± 1 , + 2 , ... , ± Ν, Ν为自然数， 为表述方便， 没有定义 η=0, 并且序号越小， 门限值就越小， 即门 限的排列顺序为 Th (- N)、 Th (-N+1) Th (- 1)、 Th (l) Th (N)。 例 如系统需要从 1/2码片的搜索精度插值到 1/8码片的精度， 则至少需要确定 4 个门限， 此时 N=2; 如果系统需要从 1/2码片的搜索精度插值到 1/4码片的精 度， 则需要确定 2个门限， 此时 N=l。 2N个门限把实数分成 2N+1个实数段， 依次定义实数段的段号为： - N， -N+1, …， 0, 1, …， N。 如果当前峰值的门限 插值操作中计算的比值 R处于门限 Th (-1)和 Th (1)之间的实数段， 即实数段 0 , 则可以认为当前峰值位置就是真正多径时延的位置， 当前峰值的能量就是真正 多径能量。 对于其它实数段， 如果实数段号为 n, 则对应真正多径的位置偏差 为 DeltaOffset (a) ,对应真正峰值能量的能量偏差因子为 AlphaEnergy (η) , 其 中 η= ±1, ±2, ··., 土 Ν, 对应实数段号。 其中时延位置一般以 0· 5码片为单 位。例如在当前峰值的门限插值操作中，计算的比值 R处于门限 Th (1)和 Th (2) 之间的实数段， 即实数段 1, 则真正峰值的位置为当前峰值位置加上 DeltaOffset (1), 真正峰值的能量为当前峰值的能量乘以 AlphaEnergy (1)。 然 后根据理想峰值形状确定位置偏差 DeltaOffset(n)和能量偏差因子 AlphaEnergy (n)的值， 定义能量偏差因子 AlphaEnergy为真正峰值能量与搜索 峰值能量之比。 例如上述 4 个门限的实施例， 对应的位置偏差为 DeltaOffset (-2) =-0.25 码 片 ， DeltaOf f set (― 1) =— 0· 125 码 片 ， DeltaOffset (1)=+0.125码片, DeltaOf f set (2) =+0.25码片。 而对于有 2个门 限的情况 ， 对应 的位置偏差为 DeltaOffset (-1)=-0.25 码 片 ， DeltaOffset (1)=+0.25码片。
在系统运行阶段执行具体的基于门限插值的多径搜索方法， 首先计算功率 时延函数 PDP (方框 302 )。 这是多径搜索的基本步骤， 在现有技术中有很多方 法计算功率时延函数， 但采用的积分长度可能会有所差别。 不同的积分长度对 本发明方法的影响甚小。 在本发明中， 首先用本地扰码和接收信号进行匹配相 关运算，获得相关函数， 然后计算相关函数的模值平方即实部和虚部的平方和， 得到不同时延的功率值。 然后进行门限插值操作（方框 303 )。 首先根椐功率时延函数 PDP的值， 选 择多个能量较大的峰值， 一般是根据系统自行制定或计算的能量门限， 选择最 多 Mpath条超过该能量门限的多径， Mpath的值可以由各系统自行制定或计算， 典型地， Mpath的取值范围是 4 ~ 16。 然后计算所选峰值的前后时延位置能量之 差与该峰值能量的比值 R,假设所选峰值的能量为 PDP ( k )，其中 k为时延位置， 则比值 R= [PDP (k- 1) - PDP (k+l) ] /PDP (k)。 将比值 R与设定的门限进行比较， 确 定比值 R所处的实数段， 然后根据实数段的值， 确定真正多径时延位置及对应 的多径能量。 如果比值 R所处的实数段为 p, 则真正多径的时延位置为所选峰 值加上比值 R所处实数段的位置偏移 Del taOff set ( p ), 其多径能量为 PDP ( k ) χ AlphaEnergy ( p X 将所选的所有峰值都按照上述步驟进行门限比较插值， 得 到相应的真正多径时延位置及多径能量。
最后确定多径时延（方框 304 )。 经过上述门限插值操作后， 得到了多个真 正多径时延位置及多径能量, 在上述多径中按能量从大到小选择 M 个多径, M 的具体取值可有各系统自行决定， 典型地， M的取值可是 1 ~ 8中的任一值， 这 些能量值对应的时延位置 tm, 其中 m = l , 2, …， M, 就是多径时延。
通过上述步骤即完成了整个多径搜索的过程， 获得多径时延。
图 4是理想的多径峰值的形状示意图。 这个理想峰值是以 256码片作为相 干积分长度、 采用 1/8码片采样精度得到的， 其中多径的真正峰值位置是 15 , 多径的真正能量为 4600左右。如果采用其它积分长度，得到的峰值形状会有所 差别。 在本实施例中， 以 256码片相干积分长度为例进行说明。
图 5是真正峰值位置与搜索峰值位置的偏差与搜索峰值前后采样点能量差 与搜索峰值能量的比值的关系。 以 256积分长度为例， 假设多径搜索的精度为 1/2码片， 则采样点位置是在图 4曲线中每相邻 4个点中选取一个点。 这样， 真正峰值的位置 15有可能无法选取，从而，搜索峰值的位置可能偏离真正峰值 位置。 位置偏差值与搜索峰值有如下特性： 位置偏差绝对值越大， 搜索峰值前 后两个采样点的能量差与峰值能量的比值 R的绝对值就越大， 而比值的符号对 应偏离的方向。 具体的关系如图 5曲线所示， 例如当位置偏差值为 0时， 比值 R为 0; 位置偏差值为 1/8码片时， 比值为 0.43; 位置偏差值为一 1/8码片时， 比值为 -0.43; 位置偏差值为 1/4码片时， 比值为 0.94。
假设系统要求搜索精度需要从 1/2码片提高 1/8码片， 则根据图 5的曲线 可定义 4个门限， 分别为 -0.68、 -0.21、 0.21和 0.68, 对应的 4个时延位置偏 差 DeltaOffset为 -0.25、 —0.125、 0.125和 0.25。
图 6给出了真正峰值和搜索峰值的能量偏差因子与搜索峰值前后采样点能 量差与搜索峰值能量的比值的关系。 以 256积分长度为例， 假设多径搜索的精 度为 1/2码片， 则采样点位置是在图 4曲线中每相邻 4个点中选取一个点。 这 样真正峰值的位置 15有可能无法取到，从而搜索峰值的能量可能低于真正峰值 的能量。 能量偏差大小和搜索峰值之间有如下特性： 能量偏差的绝对值越大， 搜索峰值前后两个采样点的能量差与峰值能量的比值 R的绝对值就越大。 具体 的关系如图 6 中曲线所示， 例如当位置偏差值为 0时， 能量差异为 0， 比值 R 为 0; 当位置偏差值为 1/8码片时， 真正峰值能量是搜索峰值能量的 1.06倍， 比值 R为 0.43; 当位置偏差值为 1/4码片时， 真正峰值能量是搜索峰值能量的 1.28倍， 比值 R为 0.94。
假设系统要求搜索精度从 1/2码片提高到 1/8码片， 则根据图 5的曲线可 义 4个门限， 分别为 -0.68、 -0.21、 0.21和 0.68, 分别对应的 4个时延位置偏 差 DeltaOffset为- 0.25、 -0.125、 0.125和 0.25, 真正能量与搜索能量的比值 AlphaEnergy为 1.28、 1.06、 1.06和 1.28。 从以上分析可知： 在本实施例中， 能量偏差因子 AlphaEnergy只需要保留 两个数据就可以了， 而时延位置偏差 Del taOffset和门限 Th的 4个数值中，如 果不考虑符号， 也只是两个不同大小的数据， 这为具体的实现带来了方便。
综上， 应用本发明多径搜索方法的 CDMA接收系统， 与现有的 CDMA接收系 统相比， 可以在保证性能不降低的情况下大幅度降低接收系统的复杂度， 而且 实现简单， 效果明显， 适用于各种码分多址通信系统。
最后所应说明的是， 以上实施例仅用以说明本发明的技术方案而非限制， 尽管参照较佳实施例对本发明进行了详细说明， 本领域的普通技术人员应当理 解， 可以对本发明的技术方案进行修改或者等同替换， 而不脱离本发明技术方 案的精神和范围， 其均应涵盖在本发明的权利要求范围当中。

Claims

权利要求书
1、 一种码分多址通信系统的多径搜索方法， 其特征在于， 包括： 首先对 接收信号计算功率时延函数， 选棒其中多个能量较大的峰值， 然后对选择的峰 值进行门限比较插值， 确定多径时延位置及能量， 最后根据插值结果确定多径 时延。
2、 根据权利要求 1所述的码分多址通信系统的多径搜索方法， 其特征在 于， 所述计算功率时延函数步骤进一步包括： 用本地扰码和接收信号进行匹配 相关运算， 获得相关函数， 计算上述相关函数的模值平方， 得到功率时延函数。
3、 根据权利要求 1所述的码分多址通信系统的多径搜索方法， 其特征在 于， 所述选择多个能量较大的峰值是根据系统自行制定或计算的能量门限， 选 择最多 Mpath条超过该能量门限的多径， Mpath的值可由系统自行制定或计算。
4、 根据权利要求 3所述的码分多址通信系统的多径搜索方法， 其特征在 于， 所述 Mpath的取值范围是 4 16。
5、 根据权利要求 1所述的码分多址通信系统的多径搜索方法， 其特征在 于，所述门限的设置进一步包括： 才艮据系统搜索精度的要求确定 2N个按大小顺 序排列的门限 Th(n), 其中 n= ± l, ±2, .·., 土 N, N为自然数， 且序号越小， 门限值就越小； 2N个门限把实数分成 2N+1个实数段， 依次定义实数段的段号 为： - N, -N+1, ..·, 0, 1, …， N; 确定位置在实数段 0的峰值为真正多径时延 位置， 其它实数段 n， 则对应真正多径的位置偏差为 DeltaOffset(n), 对应真 正峰值能量的能量偏差因子为 AlphaEnergy (n) ; 根据理想峰值形状确定位置偏 差和能量偏差因予的值。
6、 根据权利要求 5所述的码分多址通信系统的多径搜索方法， 其特征在 于， 所述对所选锋值进行门限比较插值的步驟进一步包括： 计算所选峰值前后 时延位置的能量之差与所选峰值能量的比值； 将上述比值与门限进行比较， 确 定比值所处的实数段， 然后根据实数段的值， 确定所选峰值相应的真正多径时 延位置及多径能量； 重复上述步骤， 完成全部所选峰值的门限比较插值操作。
7、 根据权利要求 6所述的码分多址通信系统的多径搜索方法， 其特征在 于， 所述峰值相应的真正多径时延位置为该峰值加上其比值所处实数段的位置 偏差， 多径能量为该峰值的能量与比值所处实数段的能量偏差因子的乘积。
8、 根据权利要求 1所述的码分多址通信系统的多径搜索方法， 其特征在 于， 所述根据插值结果确定多径时延的步骤进一步包括： 在经过所述门限比较 插值步骤获得的真正多径中， 按能量从大到小选择 M个多径， M个多径对应的 时延就是多径时延； M的取值由系统自行决定。
9、 根据权利要求 8所述的码分多址通信系统的多径搜索方法， 其特征在 于， 所述 M的取值是整数 1 ~ 8中的任一值。
PCT/CN2003/001129 2003-12-26 2003-12-26 Procede de recherche de trajets multiples d'un systeme avec acces multiple a repartition par code WO2005064833A1 (fr)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100396143C (zh) * 2006-08-09 2008-06-18 华为技术有限公司 在广覆盖下处理传输时延的方法及装置
CN101897207A (zh) * 2007-10-09 2010-11-24 高通股份有限公司 用于多模网络环境中的移动性支持和ip多媒体子系统(ims)注册的方法和装置
WO2010145537A1 (zh) * 2009-10-26 2010-12-23 中兴通讯股份有限公司 一种多径搜索方法和装置
CN101068126B (zh) * 2007-05-24 2011-06-22 中兴通讯股份有限公司 用于码分多址的峰值搜索方法和装置
CN101183881B (zh) * 2007-12-11 2012-06-27 华为技术有限公司 多径搜索方法及装置、信号接收处理方法和瑞克接收机
CN103546193A (zh) * 2012-07-09 2014-01-29 中兴通讯股份有限公司 重构处理方法及装置
WO2014075475A1 (zh) * 2012-11-19 2014-05-22 中兴通讯股份有限公司 一种信道干扰对消方法、装置和基站
US8780857B2 (en) 2007-10-09 2014-07-15 Qualcomm Incorporated Methods and apparatus for mobility support between network domains

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104181553A (zh) * 2013-05-24 2014-12-03 凹凸电子（武汉）有限公司 伪距误差估算方法和系统
CN103442431B (zh) * 2013-08-09 2016-06-15 京信通信系统（中国）有限公司 指纹定位方法与服务器

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0274157A1 (en) * 1986-12-18 1988-07-13 Koninklijke Philips Electronics N.V. Modified multi-path detector
CN1266314A (zh) * 2000-03-24 2000-09-13 深圳市中兴通讯股份有限公司 一种宽带码分多址系统中的多径筛选方法
CN1321367A (zh) * 1999-09-02 2001-11-07 诺基亚网络有限公司 处理cdma信号分量的方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2751959B2 (ja) * 1996-07-15 1998-05-18 日本電気株式会社 Ｃｄｍａ受信装置の受信タイミング検出回路
EP1089452A1 (en) * 1999-09-28 2001-04-04 Lucent Technologies Inc. Fractional sample timing error estimation for W-CDMA
US7200162B2 (en) * 2001-08-31 2007-04-03 Qualcomm, Incorporated Interpolation of channel search results

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0274157A1 (en) * 1986-12-18 1988-07-13 Koninklijke Philips Electronics N.V. Modified multi-path detector
CN1321367A (zh) * 1999-09-02 2001-11-07 诺基亚网络有限公司 处理cdma信号分量的方法
CN1266314A (zh) * 2000-03-24 2000-09-13 深圳市中兴通讯股份有限公司 一种宽带码分多址系统中的多径筛选方法

Cited By (11)

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CN100396143C (zh) * 2006-08-09 2008-06-18 华为技术有限公司 在广覆盖下处理传输时延的方法及装置
CN101068126B (zh) * 2007-05-24 2011-06-22 中兴通讯股份有限公司 用于码分多址的峰值搜索方法和装置
CN101897207A (zh) * 2007-10-09 2010-11-24 高通股份有限公司 用于多模网络环境中的移动性支持和ip多媒体子系统(ims)注册的方法和装置
CN101897207B (zh) * 2007-10-09 2013-12-25 高通股份有限公司 用于多模网络环境中的移动性支持和ip多媒体子系统(ims)注册的方法和装置
US8743887B2 (en) 2007-10-09 2014-06-03 Qualcomm Incorporated Methods and apparatus for mobility support and IP multimedia subsystem (IMS) registration in a multimode network environment
US8780857B2 (en) 2007-10-09 2014-07-15 Qualcomm Incorporated Methods and apparatus for mobility support between network domains
CN101183881B (zh) * 2007-12-11 2012-06-27 华为技术有限公司 多径搜索方法及装置、信号接收处理方法和瑞克接收机
WO2010145537A1 (zh) * 2009-10-26 2010-12-23 中兴通讯股份有限公司 一种多径搜索方法和装置
CN103546193A (zh) * 2012-07-09 2014-01-29 中兴通讯股份有限公司 重构处理方法及装置
CN103546193B (zh) * 2012-07-09 2017-02-08 中兴通讯股份有限公司 重构处理方法及装置
WO2014075475A1 (zh) * 2012-11-19 2014-05-22 中兴通讯股份有限公司 一种信道干扰对消方法、装置和基站

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