WO2011038605A1

WO2011038605A1 - Multi-path searching method and corresponding multi-path searcher in code division multiple access system

Info

Publication number: WO2011038605A1
Application number: PCT/CN2010/074752
Authority: WO
Inventors: 闫晓伟; 丁杰伟
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-09-30
Filing date: 2010-06-29
Publication date: 2011-04-07
Also published as: CN101662307A; CN101662307B

Abstract

A multi-path searcher for an Uplink Dedicated Physical Channel (UDPCH) in a Code Division Multiple Access (CDMA) system comprises an initial phase acquirement module, an initial wide-search module, a conventional small-search module, a conventional large-search module and a multi-path combination module, wherein the initial phase acquirement module is set to simultaneously start the conventional small-search module and the conventional large-search module when acquiring the initial phase of the UDPCH, the initial wide-search module is set to simultaneously start the conventional large-search module and the conventional small-search module after synchronization, the conventional large-search module is set to acquire the multi-path information of the conventional large-search according to the location information of the conventional large-search, the conventional small-search module is set to acquire the multi-path information of the conventional small-search according to the location information of the conventional small-search, the multi-path combination module is set to combine the multi-path information of the conventional large- search and that of the conventional small-search, and acquire the final multi-path set Accordingly, a multi-path search method for an UDPCH in a CDMA system is also provided. The present invention saves search resources and guarantees higher search accuracy.

Description

Multipath search method and corresponding multipath searcher in code division multiple access system

Technical field

The present invention relates to a code division multiple access mobile communication system, and more particularly to a multipath search method for an uplink dedicated physical channel and a corresponding multipath searcher in a code division multiple access system.

Background technique

The main characteristics of the wireless channel are multipath propagation and fading. The radio waves emitted from the transmitter are affected by the topographical features in the surrounding environment on the propagation path, causing diffraction, reflection or scattering, so the receiver receives more than one. A superposition of multiple signals propagated by a strip path.

Diversity and reception is an effective technique for resisting multipath fading. The code division multiple access system uses a rake receiver to process the received signal. The Rake receiver utilizes the correlation characteristics of the direct spreading sequence, uses multiple correlators to separate the multipath signals, and then combines the separated multipath signals in accordance with certain rules to obtain the maximum useful signal energy. This not only overcomes the effects of multipath propagation, but also makes full use of the useful signals of each path to improve the performance of the system.

In the code division multiple access system, the uplink signal uses a pseudo-random sequence (PN) as a scrambling code to scramble the spread spectrum signal to distinguish different users. If the local PN sequence generated by the wireless receiving end and the PN sequence of the received signal are completely synchronized, the received spread spectrum signal can be correctly despread. In order to complete the phase synchronization of the PN sequence of the received signal and effectively separate the multipath, it is necessary to correctly estimate the time delay between the transceivers and between the signals of the respective paths. At present, the pilot signal in the Dedicated Physical Control Channel (DPCCH) is usually used to estimate the multipath delay, that is, using the received baseband signal and the known scrambling code (PN sequence) and pilot symbols. At the same time, the correlation is delayed, and a correlation function is obtained. The correlation function will have a peak when the correlation delay and multipath delay are the same, and find the peak in the correlation function waveform. If the peak value is greater than a certain threshold, the delay corresponding to the peak is the multipath delay.

In the current search process of the multipath search method commonly used in the CDMA system, when the user terminal (UE) initiates an access to the base station, the UE first sends a preamble to the base station, and the base station can obtain the uplink by searching the preamble. The initial phase of the dedicated physical channel (DPCH). For the uplink With the physical channel searcher, if the initial phase of the DPCH can be obtained from the preamble search, the multipath search only needs to be performed within a narrow timing range based on the initial phase. The timing range is the search window, and its width is determined according to the characteristics of the multipath delay spread. The search at this time is called a regular small search, and the corresponding module is called a regular small search module. If the uplink dedicated physical channel searcher cannot obtain the initial phase of the DPCH from the preamble search, first multipath search is performed in the entire cell range. Since the search range is large and the search window is wide, it is called an initial wide search, and corresponding The module is called the initial wide search module. After the initial wide search determines the position of the multipath, the width of the search window can be reduced to a conventional small search. When the initial wide search is switched to the conventional small search, the multi-path information of the multipath is calculated according to the multipath information searched by the initial wide search module, thereby determining the starting position of the regular small search window. among them,

The initial wide search module searches across the entire cell, and the width of the initial search window is calculated according to equation (1);

InitWinSize = 2x CellRadius χ 12.8 + τ (1)

Among them, InitWinSize represents the size of the initial wide search window, the unit is chip; CellRadius represents the cell radius, the unit is km (Km), and τ represents the multipath delay spread.

The structure of the conventional small search module is as shown in FIG. 1, and includes a multipath detecting unit 101, a search window tracking unit 102, and a multipath updating unit 103;

The multipath detecting unit 101 is configured to calculate a correlation function of the DPCCH channel in a range of a regular small search window, dynamically calculate a peak threshold according to the obtained correlation function, perform peak detection and multipath interpolation, and obtain multipath information of the current search;

Specifically, the following steps are included:

Step 1011: The multipath detecting unit 101 performs correlation calculation using antenna data with different delays, a scrambling code, a DPCCH spreading code, and a DPCCH pilot symbol in a search window to obtain a coherent integration result of different delays of the DPCCH channel;

Step 1012: The multipath detecting unit 101 calculates the coherent integration result according to the DPCCH channel.

Correlation function of the DPCCH channel;

Specifically, the multipath detecting unit 101 calculates the amplitude or power of the DPCCH channel coherent integration result, and then accumulates the amplitude or power of several time slots to obtain a DPCCH channel non-coherent product. The result of the division is the correlation function of the DPCCH channel;

Step 1013: The multipath detecting unit 101 dynamically calculates the peak threshold according to the correlation function, and detects the peak value of the correlation function according to the correlation function and the peak threshold to obtain the multipath information with lower precision. Step 1014: The multipath detecting unit 101 detects the detected The peak value is interpolated to improve the accuracy of multipath and obtain higher accuracy multipath information.

The search window tracking unit 102 is configured to adjust the starting position of the search window according to the search window tracking algorithm according to the multipath information output by the multipath detecting unit 101, so as to ensure that the conventional small search window can still follow the multipath drift. Cover most of the multipath including the strongest path;

There are many search window tracking algorithms, which will not be described in this article.

The multipath updating unit 103 is configured to compare the saved historical multipath information with the multipath detecting unit

101 outputs the multipath information of the current search, and updates the saved historical multipath information;

Among them, there are many multipath updating methods. The method given in this paper includes the following steps: Step 1031: Comparing the delay of multipath i with the historical multipath set for a certain path i in the multipath set of this search The minimum offset of the delay of each path in the record, the multipath with the smallest offset from the multipath i in the historical multipath set is recorded as j; if the minimum offset is 0 or the minimum offset is greater than the update threshold, then more The path i is directly added to the final multipath set, wherein the update threshold is determined according to the actual situation, for example, it can be set to 1 chip; if the minimum offset is smaller than the new path threshold, the delay of the multipath i is modified to be multipath j The delay is moved to the final multipath set by moving the appropriate distance in the direction of the multipath i, wherein the distance of the movement is determined according to the actual situation, for example, it can be 1/8 chip;

Step 1032: Determine whether each multipath in the multipath set of the search has been traversed, if it is to step 1033, otherwise repeat step 1031;

Step 1033: Assign the final multipath set to the saved historical multipath set, and the multipath update ends.

The current search method that uses the initial wide search and then the regular small search has the following drawbacks:

1) The conversion time of the initial wide search to the regular small search is higher. If the initial wide search has not stably searched for the multipath center of gravity, it will be converted to the regular small search, and it is likely that the conventional small search window after the transfer will occur. The center of gravity deviates from the actual center of gravity, and because the width of the regular small search window is narrow, conventional The small search window will cause the conventional small search window to not cover most of the multipath including the strongest path, and even the case where the search cannot find the multipath and drop the call;

2) The requirements for the conventional small search window tracking algorithm are high. After the conventional small search, the range of the search window is narrow and the position of the multipath changes with the movement of the UE and the surrounding wireless environment. Adjust the position of the regular small search window in time. If the regular small search window is not adjusted in time, or improperly adjusted, there will be cases where the multipath drifts out of the window, and the conventional small search window does not search for multipath;

3) For scenarios where multipath delays such as repeaters or mountains are relatively large, in order to ensure that regular small searches can search for most multipaths including the strongest path, a wider conventional small search window needs to be set, and because Regular small searches have shorter search cycles, which requires more search resources.

For the disadvantages 1) and 2), it will affect the performance of the search. There may even be a phenomenon of dropped calls due to lack of search for the multipath, which affects the performance of the system and the subjective feelings of the user. For the drawbacks 3), either it needs to consume more search resources, or it will affect the performance of the search, and neither of these situations is what we want to see. All of these drawbacks can have very bad effects on commercial systems.

Summary of the invention

The technical problem to be solved by the present invention is to provide a multipath search method and a corresponding multipath searcher in a code division multiple access system, which saves search resources while ensuring search performance.

In order to solve the above problem, the present invention provides a multipath searcher for an uplink dedicated physical channel in a code division multiple access system, including an initial phase acquisition module, an initial wide search module, and a conventional small search module, and the multipath searcher further Including conventional large search module and multipath merge module;

The initial phase acquisition module is configured to: when acquiring the initial phase of the uplink dedicated physical channel, simultaneously start the regular small search module and the regular large search module, and send the calculated position information of the conventional large search window to the conventional large search module. Transmitting the location information of the regular small search window to the regular small search module; and sending the start signal to the initial wide search module when the initial phase of the uplink dedicated physical channel is not obtained; The initial wide search module is configured to: simultaneously start the regular large search module and the regular small search module after starting and synchronizing, and send the calculated position information of the conventional large search to the conventional large search module. Transmitting the calculated location information of the regular small search to the regular small search module;

The conventional large search module is configured to: perform multipath search according to the location information of the conventional large search, obtain multipath information of the regular large search, and send the multipath information to the multipath combining module;

The conventional small search module is configured to: perform multipath search according to the location information of the regular small search, obtain multipath information of the regular small search, and send the multipath information to the multipath combining module;

The multipath combining module is configured to: combine the multipath information of the regular large search and the multipath information of the regular small search to obtain a final multipath set;

Wherein, the width of the conventional large search window of the conventional large search module is smaller than the initial wide search window, but larger than the conventional small search window.

The multipath searcher described above also has the following features:

The location information includes: a starting location, a center of gravity location, or an ending location.

The multipath searcher described above also has the following features:

The conventional large search module includes a first multipath detecting unit, a first search window tracking unit, and a first multipath updating unit;

The first multipath detecting unit is configured to: determine a position of a regular large search window according to position information of a conventional large search window, acquire multipath information of a conventional large search of the current search, and send the tracking to the first search window. a unit and the first multipath update unit;

The first search window tracking unit is configured to: calculate position information of the regular large search window according to the multi-path information of the conventional large search output by the first multipath detecting unit, and feed back to the first multipath detecting unit;

The first multipath updating unit is configured to: update the multipath information of the regular large search according to the multipath information of the regular large search output by the first multipath detecting unit.

The multipath searcher described above also has the following features:

The conventional small search module includes a second multipath detecting unit, a second search window tracking unit, and a Two multipath update unit;

The first multipath detecting unit is further configured to: send the multipath information of the regular large search to the second search adjusting unit;

The second multipath detecting unit is configured to: determine a location of the regular small search window according to the location information of the regular small search window, acquire multipath information of the conventional small search of the current search, and send the tracking to the second search window. a unit and the second multipath update unit;

The second search window tracking unit is configured to: multipath information of the regular large search output by the first multipath detecting unit and multipath of the conventional small search output by the second multipath detecting unit Information, calculating location information of the regular small search window, and feeding back to the second multipath detecting unit;

The second multipath updating unit is configured to: update the multipath information of the regular small search according to the multipath information of the regular small search output by the second multipath detecting unit.

In order to solve the above problems, the present invention provides a multipath search method for an uplink dedicated physical channel in a code division multiple access system, including:

A. When the user terminal accesses the base station, if the base station acquires the initial phase of the uplink dedicated physical channel, calculates the location information of the regular large search window and the location information of the regular small search window, and executes C, if the base station does not acquire To the initial phase of the uplink dedicated physical channel, perform B;

B. After the initial wide search acquires the starting position of the regular large search window and the regular small search window, the regular large search and the regular small search are simultaneously started;

C. Regular large search determines the position of the regular large search window according to the position information of the conventional large search window, performs multipath search and obtains multipath information of the conventional large search, and at the same time, the regular small search according to the conventional small search window Position information, determine the location of the regular small search window, perform multipath search and obtain multipath information of the regular small search;

D. Combining the multipath information of the conventional large search with the multipath information of the conventional small search to obtain a final multipath set.

The above multipath search method also has the following characteristics:

The location information includes a starting location, a center of gravity location, or an ending location. The above multipath search method also has the following characteristics:

Step D includes:

Copying the multipath information of the conventional small search one by one into the final multipath set; and sequentially determining whether each multipath in the multipath information of the regular large search falls within the regular large search window and outside the regular small search window, If not, the final multi-transmission set is not added. If yes, it is determined whether the energy of each multipath is greater than the multipath combined energy threshold. If yes, the multipath information corresponding to the multipath is copied to the final multipath set, otherwise the final multipath is not added. After collection, the final multipath set is obtained.

The above multipath search method also has the following characteristics:

After the step D, the method further includes:

According to the order of the multipath energy from the largest to the smallest, the M multipaths with the largest energy are selected from the final multipath set, where M is an integer.

The above multipath search method also has the following characteristics:

After the step of selecting the M-multipath with the largest energy from the final multipath set in the order of the multipath energy from the largest to the smallest, the method further includes:

If the distance between the multipath of the final multipath set and any of the multipaths that have been selected in the final multipath set is less than the dense path threshold, the multipath with less energy after the deletion is deleted.

The above multipath search method also has the following characteristics:

In step C, after the regular large search performs a multipath search, the step C further includes a regular large search window tracking, and the step of the conventional large search window tracking includes:

The conventional large search adjusts the conventional large search window according to the searched multi-path information of the conventional large search to ensure that the conventional large search window can still cover the strongest path, including the most powerful path. Most of the multipath.

The above multipath search method also has the following characteristics:

In step C, after performing the multi-path search, the conventional small search further includes a regular large search window tracking, and the step of the conventional large search tracking includes: ensuring that the regular small search window is within the range of the regular large search window. And adjusting, according to the multipath information of the conventional small search and the multipath information of the conventional large search, the step of adjusting includes: Step a: finding the strongest path of energy from the conventional large search to the multipath set and the multipath set of the regular small search;

Step b: determining whether the strongest path is in a regular large search window, and in a regular small search window, if yes, go to step C, if not, go to step k;

Step c: add a unit to the global variable;

Step d: determining whether the global variable is greater than the regular small search window tracking threshold. If it is greater than, performing step e, if not greater than, the conventional small search window tracking ends;

Step e: calculating, as the position of the center of gravity of the conventional small search window, the position of the strongest path, and calculating the starting position of the conventional small search window;

Step f: determining whether the starting position of the conventional small search window falls before the starting position of the regular large search window, if yes, go to step g, if not, go to step h;

Step g: placing the starting position of the conventional small search window at the beginning of the regular large search window, performing step j;

Step h: determining whether the end position of the regular small search window falls after the end position of the regular large search window, if yes, performing step i, if not, proceeding to step j;

Step i: The end position of the regular small search window is placed at the end position of the regular large search window, and the starting position of the regular small search window is calculated;

Step j: adjusting a regular small search window according to a starting position of a regular small search window;

Step k: The value of the global variable is cleared to indicate that there is no number of times the strongest path continuously falls within the regular small search window, and the tracking of the search window ends.

The multipath search method and the multipath searcher save the search resources; among them, it can ensure coverage of a large range in a large range, and high search accuracy is ensured.

Compared with the multi-path search method of the initial wide search plus the conventional small search, the multi-path search method of the three search windows of the present invention reduces the sensitivity to the wide search to conventional search algorithm and the conventional search window tracking algorithm. It reduces the possibility of dropped calls in the system due to the lack of multipath searching, which greatly improves the stability of the system and the subjective feelings of users. In addition, in scenes with large multipath delays such as repeaters and mountains, to ensure the performance of the search (such as detection probability, false alarm probability, accuracy of search multipath), existing methods need to increase the regular small search. The width of the window, due to its short search period, the computational complexity of the process of calculating the correlation function will increase, requiring more search resources. However, with the present invention, there is no need to increase the size of the conventional small search window. Although it is necessary to additionally increase the conventional large search, the increase of the search resource is limited because the search cycle of the conventional large search is long. In summary, in the scenario where the multipath delay is large, the present invention can save performance while saving performance while using the existing method.

BRIEF abstract

1 is a structural diagram of a conventional small search that is common in the prior art;

2 is a structural diagram of a conventional small search and a conventional large search and multipath combination in an embodiment of the present invention;

3 is a flowchart of a conventional small search window tracking algorithm in an embodiment of the present invention;

4 is a flow chart of a multipath merging algorithm in a searcher in an embodiment of the present invention.

Preferred embodiment of the invention

In order to achieve search performance while saving resources, the present invention proposes a multipath search method and a multipath searcher for initial wide search, conventional large search, and conventional small search. When the UE accesses the base station, if the uplink dedicated physical channel searcher obtains the initial phase of the DPCH from the preamble search, the regular large search and the regular small search are directly performed simultaneously; otherwise, the initial wide search is started first, after the initial wide search synchronization, simultaneously Switch to regular small search and regular large search.

Wherein, the conventional large search is a new search in the present invention relative to the existing universal search method, and the search process is the same as the conventional small search in the existing universal search method; considering the search resources, the search accuracy is guaranteed. Based on this, the regular large search has a longer search cycle.

The width of the conventional large search window is smaller than the initial wide search window, but larger than the conventional small search window, and the conventional large search can ensure that the search window can cover most of the multipath in various scenes.

Conventional small search: The width of the regular small search window only needs to meet the needs of multipath delay expansion in most application scenarios. The conventional small search search process is the same as the regular small search in the current general search method. In order to guarantee the performance of the search, the search period of the search is short.

The invention reduces the requirement for the initial wide search conversion timing by adding a conventional large search, that is, the invention shifts from the initial wide search to the conventional small search and the regular large search, so that even if the deviation is made, the conventional large search window The width is wider, it can still search for multipath, and there is no possibility of searching for multipath. In addition, in the scenario where the multipath delay is large, the present invention can save search resources while ensuring search performance.

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

When the UE accesses the base station, if the uplink dedicated physical channel searcher obtains the initial phase of the DPCH from the preamble search, the conventional large search and the regular small search are directly performed simultaneously; otherwise, the initial wide search is started first, after the initial wide search synchronization, simultaneously Switch to regular small search and regular large search. The multipath searcher of the embodiment includes an initial phase acquisition module, an initial wide search module, a regular small search module, a conventional large search module, and a multipath merge module;

The initial phase acquisition module is configured to simultaneously start the regular small search module and the regular large search module when acquiring the initial phase of the DPCH, and send the calculated position information of the conventional large search window to the regular large search module, and the conventional small search The position information of the window is sent to the regular small search module; and when the initial phase of the DPCH is not obtained, the start signal is sent to the initial wide search module;

The initial phase used for acquiring the DPCH is obtained by the base station by detecting a preamble sent when the UE accesses the base station.

The initial wide search module is configured to perform multipath search in a cell range after receiving the start signal, and simultaneously start the regular large search module and the regular small search module after the synchronization, and calculate the calculated location information of the conventional large search. And the location information of the regular small search is sent to the regular large search module and the regular small search module respectively;

The location information of the conventional large search may be one or more of a starting position, a center of gravity position and an ending position of the regular large search window, preferably a starting position;

Similarly, the location information of the regular small search may be one or more of a starting position, a center of gravity position and an ending position of the regular small search window, preferably a starting position; The initial wide search search process is the same as the initial wide search in the prior art common search method; it will not be described in detail in this embodiment;

a conventional large search module, configured to determine a location of a regular large search window according to the received location information of the conventional large search, perform multipath search, obtain multipath information of the regular large search, and send the multipath information to the multipath merge module;

Wherein, the conventional large search is a multi-path search in which the search period is larger than the regular small search search period, the width of the regular large search window is smaller than the initial wide search window, but larger than the conventional small search window;

The conventional large search is mainly used to ensure the coverage of the search, and the search period is longer than the regular small search search period, and can be set according to the requirements of the system, which can be 4 to 20 times of the regular small search period; the width of the conventional large search window It can be 2~5 times of the width of the regular small search window. In the specific implementation, it can be set according to the different needs of the system. For example, when the search performance is biased, the search period is shorter and the search window is wider. When the search resource is limited, the search period is shorter and the search window is narrower.

The conventional small search module is used for determining the position of the regular small search window according to the position information of the conventional small search and ensuring that the regular small search window falls within the range of the regular large search window, and performing multipath search to obtain the regular small search. Multipath information, and sent to the multipath merge module;

The structure of the conventional small search module is the same as that of the conventional small search module in the prior art; the width setting of the conventional small search window currently has a plurality of algorithms, and these algorithms can be applied to the present invention. In this embodiment, only It can meet the requirements of multipath delay extension in most application scenarios, and can choose a value after considering the search performance and system complexity. It can range from 32 chips to 128 chips.

The multipath merging module is configured to combine the multipath information of the conventional large search and the multipath information of the regular small search to obtain the final multipath set.

FIG. 2 is a structural diagram showing a conventional small search and a conventional large search and multipath combination in the present embodiment;

The conventional large search module 201 includes a multipath detecting unit 201-a, a search window tracking unit 201-b, and a multipath updating unit 201-c;

The multipath detecting unit 201-a is configured to determine a conventional large search according to the location information of the conventional large search window Positioning the window, obtaining the multipath information of the conventional large search of the current search and sending it to the search window tracking unit 201-a, the search window tracking unit 201-b and the multipath updating unit 201-c;

The function and processing of the unit are the same as the multi-path detecting unit 101 of the conventional small search of the universal searcher in the background art, wherein the multipath information of the conventional large search for obtaining the current search is the same as the method in the prior art, specifically By calculating the correlation function of the DPCCH channel, the peak threshold is dynamically calculated according to the correlation function, and the peak detection and multipath interpolation of the correlation function are performed, and the multipath information of the conventional large search of the current search is obtained.

The search window tracking unit 201-b is configured to calculate the position information of the regular large search window according to the multipath information of the conventional large search output by the multipath detecting unit 201-a and feed back to the multipath detecting unit 201-a; The purpose is to adjust the position of the conventional large search window to ensure that the conventional large search window can cover most of the multipath including the strongest path as the multipath drifts; the specific adjustment algorithm can refer to the prior art. The search window tracking algorithm in the present embodiment is not described in detail in this embodiment; the multipath updating unit 201-c is configured to update the conventional large search module according to the multipath information of the current search output by the multipath detecting unit 201-a. Multipath collection;

The function and processing of the unit are the same as those of the conventional small search multipath update unit 102 of the prior art in the prior art, which will not be described herein.

The conventional small search module 202 includes a multipath detecting unit 202-a, a search window tracking unit 202-b, and a multipath updating unit 202-c;

The multipath detecting unit 202-a is configured to determine a location of the regular small search window according to the location information of the regular small search window, obtain multipath information of the regular small search of the current search, and send the multipath information of the regular small search To the search window tracking unit 202-b;

The function and processing of this module are the same as those of the conventional small search multipath detecting unit 101 of the universal searcher in the background art, and will not be described herein.

The search window tracking unit 202-b is configured to calculate a conventional small search window according to the multipath information of the conventional large search output by the multipath detecting unit 202-a and the multipath information of the conventional small search output by the multipath detecting unit 202-b. Location information, and feedback to the multipath detecting unit 202-a;

The multipath updating unit 202-c is configured to update the multipath set of the regular small search according to the multipath information of the conventional small search of the current search output by the multipath detecting unit 202-a; The function and processing of the multipath updating unit 202-C are the same as those of the conventional small search multipath updating unit 102 of the prior art universal searcher introduced in the background art, and details are not described herein again.

The multipath combining module 203 is configured to combine the multipath set of the regular large search and the multipath set of the regular small search to obtain the final multipath set;

Further, this embodiment provides a multipath search method based on the multipath searcher in the uplink dedicated physical channel, which specifically includes the following steps:

Step A: When the UE accesses the base station, if the base station can obtain the initial phase of the DPCH by detecting the preamble sent when the UE accesses the base station, step C is performed, otherwise step B is performed;

Step B: Start the initial wide search, perform multipath search, and obtain the location information of the regular large search window and the regular small search window, and perform step D;

Wherein, the conventional large search is to perform an initial wide search within the entire cell range;

If the location information is the starting location, the starting positions of the conventional large search window and the regular small search window may be: The initial wide search calculates the position of the center of gravity of the multipath based on the searched multipath information, and according to the center of gravity of the multipath The positions respectively calculate the starting positions of the conventional large search window and the regular small search window; of course, it is not limited thereto;

Step C: calculating the position information of the conventional large search window and the position information of the conventional small search window according to the initial phase of the DPCH, and performing step D;

Step D: The conventional large search determines the position of the regular large search window according to the position information of the conventional large search window, performs multipath search and acquires the multipath information of the conventional large search, and the regular small search is determined according to the position information of the regular small search window. Position of a conventional small search window, perform multipath search and obtain multipath information of a regular small search;

Step E: Combine the multipath information of the conventional large search with the multipath information of the regular small search to obtain the final multipath set.

In step D:

After the regular large search performs a multipath search, it also includes: The regular large search adjusts the regular large search window according to the searched multipath information to ensure that the regular large search window can still be covered as the multipath drifts. Most multipaths including the strongest path; After performing a multipath search in a regular small search, the conventional small search window is adjusted according to the multipath information of the conventional small search and the multipath information of the conventional large search in the range of ensuring the regular small search window within the regular large search window. ;

In order to further save resources, the present embodiment provides a preferred implementation manner for adjusting a conventional small search window. As shown in FIG. 3, the method includes the following steps:

Step 301: Find the strongest energy path from the multipath information of the conventional large search and the multipath information of the conventional small search;

Step 302: Determine whether the strongest path is in the regular large search window and outside the regular small search window. If yes, go to step 303, otherwise go to step 311;

Due to the starting position of the regular large search, the length of the regular large search window, the end position of the regular large search is known; the starting position of the regular small search, the regular small search window length, the regular small search to the end position is known When the strongest path is found, it can be judged whether the strongest path is in the regular large search window and outside the regular small search window;

Step 303: Add a unit to the global variable for identifying the number of times the strongest path continuously falls within the regular small search window in the regular large search window;

The 1 unit can be 1;

The purpose of adding 1 to the global variable is to indicate that the strongest path still falls within the regular large search window and outside the regular small search window; the value of the global variable can be initialized to the first time the regular small search is performed.

0; Of course, it can be other values;

Step 304: Determine whether the global variable is greater than the regular small search window tracking threshold. If yes, go to step 305, otherwise the regular small search window tracking ends.

Step 305: Calculate the starting position of the regular small search window by using the position of the strongest path as the center of gravity of the conventional small search window;

Step 306: Determine whether the starting position of the regular small search window falls before the start position of the regular large search window, if it is to step 307, otherwise go to step 308;

Step 307: The starting position of the regular small search window is placed at the starting position of the regular large search window; step 310 is performed;

Step 308: Determine whether the end position of the regular small search window falls at the end of the regular large search window. After the location, if it is step 309, otherwise go to step 310;

Step 309: The end position of the regular small search window is placed at the end position of the regular large search window, and the start position of the regular small search window is calculated; Step 310: Adjust the regular small search window according to the starting position of the regular small search window;

Step 311: Clear the value of the global variable to indicate that there is no maximum strength continuously falling within the regular small search window, and the search window ends.

For example, the global variable identifying the number of times the strongest path continuously falls within the regular small search window can be used to indicate the number of times that the strongest path does not continuously fall within the regular small search window.

In the step E, the multipath information of the conventional large search and the multipath information of the conventional small search are combined, and the final multipath set can be obtained in various implementation manners. In this embodiment, a multipath merge is provided. A preferred embodiment, as shown in FIG. 4, specifically includes the following steps:

Step 401: Copy the multipath information of the regular small search one by one into the final multipath set; since the search cycle of the regular small search is short and the search precision is high, the embodiment directly uses the search result as a part of the final search result, and copies Go to the final multipath collection.

Step 402: The count i is assigned a value of 1;

The counting is to ensure that each multipath in the conventional large search multipath set can be processed; Step 403: judging whether the i th multipath in the regular large search multipath set falls within the regular large search window and in the regular small search Outside the window, if no, step 405 is performed, otherwise it is determined whether the i-th multi-path to energy is greater than the multi-path merge energy threshold, if yes, step 404 is performed, otherwise step 405 is performed;

In order to reduce the false alarm probability of the conventional large search, a multi-combined energy threshold is further set, and the multi-combined energy threshold can take a larger one of the conventional large search peak threshold and the conventional small search peak threshold. Not limited to this;

Because the update period of the regular large search is long, the search accuracy and performance are slightly poor. Therefore, in order to ensure the quality of the multipath selected in the final multipath set, the multipath combined energy threshold is set here to select the multipath; Step 404: Putting the routine The i-th multipath information in the large search multipath set is copied into the final multipath set;

The copy content may include an antenna number corresponding to multipath, multipath offset, multipath energy, and more One or more of the contents of the path, etc.;

Step 405: Count i plus 1;

Step 406: Determine whether the count i is greater than the number of multipaths in the conventional large search multipath set; if yes, go to step 407, otherwise go to step 403;

Step 407: Select the M multipath with the largest energy from the final multipath set;

Among them, the value of M is related to the specific system. The M value is small, saving search resources, but the search performance is poor; the M value is large, the search performance is good, and more search resources are needed. In a specific implementation, the value is selected in consideration of search performance and search implementation complexity, and the value used in this embodiment is 6 paths.

In the process of selection, the multipath energy can be further increased in descending order. If the distance between the multipath and the selected multipath is less than the dense path threshold, the multipath with less energy is deleted. ;

In the code division multiple access system, the minimum distance between multipaths that the multipath searcher can distinguish is 1 chip, so the dense path threshold is set to 1 chip, and of course, is not limited to 1 chip.

One of ordinary skill in the art will appreciate that all or a portion of the steps above may be accomplished by a program to instruct the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware or in the form of a software function module. The invention is not limited to any specific form of combination of hardware and software.

Industrial applicability

Compared with the prior art, the present invention employs a multipath search method combining initial wide search, conventional large search, and conventional small search. The initial wide search is used to search across the entire cell for link creation or addition to determine the approximate location of the multipath. After the initial wide search is stably received, the conventional large search and the regular small search are simultaneously performed. The conventional large search has a long search cycle, which can save search resources. The conventional large search has a wide search window, which can ensure coverage of a large range in a large range. The conventional small search window is narrow in the range of the conventional large search window, and the search window is narrow, which can save search resources; The search cycle of the small search is shorter, and the search accuracy of the larger energy multipath can be ensured. After each regular small search ends, the results of the regular large search and the regular small search are merged, and the combined results are sent to the Rake receiver as the final multipath set. The combination of conventional large search and regular small search can not only ensure a wide search range, but also ensure the search accuracy of a larger energy path, and also save search resources.

Claims

Claim

A multipath searcher for an uplink dedicated physical channel in a code division multiple access system, comprising an initial phase acquisition module, an initial wide search module, and a conventional small search module, the multipath searcher further comprising a conventional large search module and The initial phase acquisition module is configured to: when acquiring the initial phase of the uplink dedicated physical channel, simultaneously start the regular small search module and the regular large search module, and send the calculated position information of the conventional large search window to The conventional large search module sends the location information of the regular small search window to the regular small search module; and when the initial phase of the uplink dedicated physical channel is not obtained, sends a start signal to the initial wide search module;

The initial wide search module is configured to: simultaneously start the regular large search module and the regular small search module after starting and synchronizing, and send the calculated position information of the conventional large search to the conventional large search module. Transmitting the calculated location information of the regular small search to the regular small search module;

2. The multipath searcher according to claim 1, wherein

The multipath searcher according to claim 1 or 2, wherein the conventional large search module includes a first multipath detecting unit, a first search window tracking unit, and a first multipath updating unit;

The first multipath detecting unit is configured to: determine a regularity according to position information of a conventional large search window The location of the large search window, the multipath information of the conventional large search of the current search is obtained, and sent to the first search window tracking unit and the first multipath update unit;

The multipath searcher according to claim 3, wherein the conventional small search module includes a second multipath detecting unit, a second search window tracking unit, and a second multipath updating unit;

5. A multipath search method for an uplink dedicated physical channel in a code division multiple access system, comprising:

C. Regular large search determines the regular large search window according to the position information of the conventional large search window Position, performing multipath search and obtaining multipath information of a conventional large search. Meanwhile, the regular small search determines the position of the regular small search window according to the position information of the conventional small search window, performs multipath search, and obtains a regular small search. Multipath information;

6. The multipath searching method according to claim 5, wherein

The location information includes a starting location, a center of gravity location, or an ending location.

The multipath searching method according to claim 5 or 6, wherein the step D comprises: copying the multipath information of the regular small search one by one into the final multipath set; and sequentially determining the multipath of the regular large search Whether each multipath in the information falls within the regular large search window and outside the regular small search window. If it is not added to the final multi-transition set, if yes, it is judged whether the energy of each multipath is greater than the multipath combined energy threshold. Yes, the multipath information corresponding to the multipath is copied to the final multipath set, otherwise the final multipath set is not added, and the final multipath set is obtained.

The multipath searching method according to claim 7, wherein after the step D, the method further includes:

The multipath searching method according to claim 8, wherein after the step of selecting the M multipaths having the largest energy from the final multipath set in the order of the multipath energy from the largest to the smallest, The method also includes:

The multipath searching method according to claim 5 or 6 or 8 or 9, wherein, in step C, after the regular large search performs a multipath search, the step C further includes a regular large search window tracking. The step of tracking the conventional large search window includes:

The conventional large search adjusts the regular large search window according to the searched multi-path information of the conventional large search to ensure that the regular large search window can still cover the following as the multipath drifts. Most multipaths, including the strongest path.

The multipath searching method according to claim 5 or 10, wherein, in step C, after the regular small search performs a multipath search, the step C further includes a regular large search window tracking, the regular The step of large search tracking includes: adjusting the regular small search window according to the multipath information of the regular small search and the multipath information of the conventional large search in the range of ensuring the regular small search window within the regular large search window. The steps of the adjustment include:

Step a: finding the strongest energy path from the multipath set of the conventional large search and the multipath set of the regular small search;

Step c: add a unit to the global variable;