CN1863355A - TD SCDMA terminal and cell searching method under common-frequency network - Google Patents
TD SCDMA terminal and cell searching method under common-frequency network Download PDFInfo
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Abstract
This invention discloses a TD-SCDMA terminal and a search method for local areas under a same frequency network, in which, a multi-area selection module and a multi-area confirmation module are set in the TD-SCDMA terminal, said method includes: first of all carrying out down pilot time slot position synchronization to get a multi-area list, carrying out carrier frequency adjustment and confirmation of basic training sequence codes/harass codes, then confirming and getting a multi-area list containing related power values of the areas and corresponding sequence codes/harass codes, finally accurately adjusting the carrier frequency, confirming phases of the log-on areas and reading their system information.
Description
Technical Field
The present invention relates to a mobile communication technology, and in particular, to a TD-SCDMA (time Division-Synchronous Code Division Multiple Access) terminal and a cell search method thereof in a co-frequency network.
Background
In the actual networking of the TD-SCDMA system, in order to further increase the capacity of the TD-SCDMA system, the same frequency networking is usually adopted. That is, a complete TD-SCDMA system network can operate on a single carrier frequency. In this case, it is required that the terminal of the TD-SCDMA system can support the same frequency access and the same frequency demodulation.
In the TD-SCDMA co-frequency network, after the TD-SCDMA terminal is powered on, synchronization with the network needs to be realized through a search process of an initial cell, that is, downlink synchronization codes, basic training sequence code/scrambling code confirmation, system information multi-frame synchronization, and system information reading of a login cell need to be realized to complete successful cell residence.
As shown in fig. 1, in the intra-frequency network, the step of the TD-SCDMA terminal searching for the cell includes the following steps:
102, synchronizing the rough position of the downlink pilot frequency time slot;
103, carrying out accurate position synchronization of a downlink pilot frequency time slot, and simultaneously confirming a downlink synchronous code of a login cell;
104, estimating and adjusting carrier frequency on the determined carrier and downlink synchronous code;
105, confirming basic training sequence codes/scrambling codes of the cells with the determined carrier and downlink synchronous codes;
106, accurately adjusting carrier frequency under the determined carrier, downlink synchronous code and basic training sequence code/scrambling code;
After a terminal successfully logs in a TD-SCDMA cell suitable for logging in, the terminal can arrange a period of time according to the received system information containing the same-frequency neighbor cell list, measure each cell one by one according to the neighbor cell list, and sort according to a certain measurement result, for example, according to the power sequence of the received signal codes, so as to obtain a list of multi-cell information. In the next downlink data reception, the same-frequency multi-cell demodulation algorithm can be used to demodulate data by using the multi-cell information in the list. The same-frequency multi-cell demodulation algorithm can be used only after the system information of the login cell is successfully read. And in the initial cell search stage, the cell search method only using a single cell comprises the process of initially reading the system information of the logged-in cell.
The single cell algorithm cannot overcome the interference due to the co-channel cells at the initial cell stage. For example, in a TD-SCDMA system of a co-frequency network in which a terminal logs in, when a power difference between a logged-in cell and an adjacent cell searched by the terminal is not large, due to fading, time spreading, and the like, in data received by the terminal, the power of the logged-in cell is even smaller than that of the co-frequency adjacent cell when carrier frequency estimation and adjustment, carrier frequency precise adjustment, logged-in cell phase determination, and logged-in cell system information reading are performed. At this time, if the single-cell search method described in fig. 1 is still used, the interference caused by the same-frequency neighboring cells cannot be overcome, thereby reducing the probability of successfully completing the task, and causing a network login failure.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a TD-SCDMA terminal and a cell searching method thereof in a same-frequency network, which utilize the obtained same-frequency multi-cell information to carry out frequency adjustment and phase confirmation of a login cell and system message reading of the login cell, thereby greatly improving the probability of successful network login of the terminal.
The TD-SCDMA terminal of the invention comprises a central processing unit and a functional module, and is additionally provided with a multi-cell information selection module and a multi-cell information confirmation module; wherein,
the multi-cell selection module is used for performing multi-cell selection according to the downlink pilot frequency time slot position synchronization result to obtain a multi-cell list containing downlink synchronization code information and corresponding code power measurement value information;
the TD-SCDMA terminal adjusts the carrier frequency and confirms the basic training sequence code/scrambling code of the multi-cell according to the multi-cell list information;
the multi-cell confirming module is used for confirming basic training sequence codes/scrambling codes of the multi-cell to obtain a multi-cell list containing the relevant power value of each cell and the corresponding basic training sequence codes/scrambling codes;
and the TD-SCDMA terminal performs carrier frequency precise adjustment, cell login phase confirmation and cell login system information reading according to the relevant power value of each cell in the multi-cell list obtained by the multi-cell confirmation module and the corresponding basic training sequence code/scrambling code.
The invention also provides a cell searching method of the TD-SCDMA terminal in the same frequency network, which comprises the following steps:
step one, a TD-SCDMA terminal carries out downlink pilot frequency time slot position synchronization;
step two, selecting multiple cells according to the downlink pilot frequency time slot position synchronization result to obtain a multiple cell list containing downlink synchronization code information and corresponding code power values;
step three, carrier frequency adjustment and multi-cell basic training sequence code/scrambling code confirmation are carried out according to the multi-cell list information;
confirming the basic training sequence codes/scrambling codes of the multiple cells to obtain a multiple cell list containing the relevant power value of each cell and the corresponding basic training sequence codes/scrambling codes;
and fifthly, carrying out carrier frequency precise adjustment, login cell phase confirmation and login cell system information reading according to the relevant power value of each cell in the multi-cell list and the corresponding basic training sequence code/scrambling code.
In the second step, the multi-cell selection step includes:
step A1, selecting the largest measured value from the measured values of the code power corresponding to all the cell downlink synchronous codes and recording the corresponding downlink synchronous codes;
step A2, comparing the code power measurement value of the downlink synchronous codes of other cells with the difference between the maximum measurement value of the code power and the set threshold value, selecting the corresponding cell with the downlink synchronous code power measurement value greater than the difference value, and recording the downlink synchronous codes and the corresponding code power in a multi-cell list;
step a3, the multi-cell list is sorted according to the size of the code power.
In the fourth step, the step of multi-cell acknowledgement includes:
step B1, comparing the correlation power of the basic training code/scrambling code of each cell with the difference between the correlation power value corresponding to the basic training sequence code/scrambling code of the landing cell and a threshold;
step B2, selecting the cell corresponding to the basic training sequence code/scrambling code whose correlation power is larger than the difference value as the interference cell;
and step B3, sorting the selected multiple cells according to the related power to obtain a multiple cell list.
According to the invention, by acquiring the multi-cell information and utilizing the multi-cell information to perform frequency adjustment, phase confirmation and system message reading of the logged-in cell, the interference of the same-frequency adjacent cell is overcome, and the probability of successfully logging in the cell is improved.
Drawings
FIG. 1 is a flowchart illustrating a method for a TD-SCDMA terminal to search a cell in the prior art;
FIG. 2 is a schematic diagram of a TD-SCDMA terminal structure according to the present invention;
FIG. 3 is a flowchart of a method for a TD-SCDMA terminal to search a cell according to the present invention;
FIG. 4 is a flowchart of a method for multi-cell selection by a TD-SCDMA terminal according to the present invention;
FIG. 5 is a flowchart of a method for a TD-SCDMA terminal to perform multi-cell acknowledgement according to the present invention.
Detailed Description
In the invention, a multi-cell selection module and a multi-cell confirmation module are added in the TD-SCDMA terminal, and the TD-SCDMA terminal utilizes the acquired multi-cell information to carry out carrier frequency precise adjustment, phase confirmation and system information reading in the cell searching process, thereby improving the probability of the TD-SCDMA terminal successfully logging in the cell.
The invention is further described below with reference to the accompanying drawings.
As shown in fig. 2, the TD-SCDMA terminal of the present invention includes a central processing module and other functional modules, and further includes a multi-cell selection module and a multi-cell confirmation module.
The functional module is used for completing the setting function of the terminal, for example, the functional module can be an information output module for completing information output, namely a display screen; the information input module for completing information input, namely a keyboard; and an information storage module that stores information, and the like.
The multi-cell selection module is used for selecting multiple cells according to the downlink pilot frequency time slot position synchronization result to obtain a multi-cell list containing downlink synchronization code information and corresponding code power measurement value information. After the terminal carries out the rough position synchronization of the downlink pilot frequency time slot and the precise position synchronization of the downlink pilot frequency time slot, the terminal can output the code power measured values and the corresponding positions of the downlink synchronous codes of all the cells. Then, the multi-cell selection module selects the largest measured value from the code power measured values corresponding to the downlink synchronous codes of all the cells and records the corresponding downlink synchronous code, compares the code power measured values corresponding to the downlink synchronous codes of the other cells with the difference between the code power largest measured value and the set threshold value, selects the corresponding cell with the code power measured value of the downlink synchronous code larger than the difference, records the downlink synchronous code of the selected cell and the corresponding code power measured value in the multi-cell list, and then sorts the multi-cell list according to the size of the code power measured value. Thus, a multi-cell list sorted according to the size of the code power measured value is obtained, and the list comprises the downlink synchronous code information and the corresponding code power measured value information.
And the TD-SCDMA terminal adjusts the carrier frequency and confirms the basic training sequence code/scrambling code of the multi-cell according to the multi-cell list information. The TD-SCDMA terminal firstly needs to receive a section of data containing downlink synchronous codes, then uses the downlink synchronous codes of the cells to be searched and the downlink synchronous codes of the cells to carry out carrier frequency deviation estimation, carries out most probability analysis on the estimation result, carries out weighted average on the frequency deviation estimation value with stronger relativity, and determines the weight value according to the power measurement value of the downlink synchronous codes in the multi-cell list, thereby obtaining the final frequency deviation value and carrying out control adjustment. This process needs to be performed several times to meet the carrier frequency offset to the set range, for example, to a target of less than 1 kHz. After the TD-SCDMA terminal is synchronized at the accurate position of the downlink pilot time slot, the training sequence part data of the time slot 0 can be found, 4 basic training sequence codes/scrambling codes corresponding to each downlink synchronous code are respectively correlated with the received training sequence data of the time slot 0, and the correlation power is calculated. For the search cell, the basic midamble code/scrambling code corresponding to the maximum correlation power value is the basic midamble code/scrambling code corresponding to the search cell.
The multi-cell confirmation module is used for confirming the basic training sequence codes/scrambling codes of the multi-cell to obtain a multi-cell list containing the relevant power value of each cell and the corresponding basic training sequence codes/scrambling codes. The multi-cell confirming module compares the difference value between the relevant power value corresponding to the basic training sequence code/scrambling code of the login cell and a threshold, wherein the relevant power value of the basic training code/scrambling code of each cell is larger than the relevant power value corresponding to the basic training sequence code/scrambling code of the login cell; selecting the cell corresponding to the basic training sequence code/scrambling code with the correlation power larger than the difference value as an interference cell; and sequencing the selected multiple cells according to the related power to obtain a multiple cell list.
And the TD-SCDMA terminal performs carrier frequency precise adjustment, cell login phase confirmation and cell login system information reading according to the relevant power value of each cell in the multi-cell list obtained by the multi-cell confirmation module and the corresponding basic training sequence code/scrambling code.
When the frequency is accurately adjusted, the carrier frequency deviation estimation is mainly carried out by using the data of the main common control channel on the time slot 0 in the frame structure. The specific process is as follows: first, data of the whole time slot 0 is received, and the time slot 0 is jointly detected. When channel estimation of joint detection is carried out, channel estimation needs to be carried out by using a basic training sequence code of a search cell and a multi-cell training sequence code in a multi-cell list, and original channel estimation of multiple cells is obtained; then, the mutual interference elimination is carried out on the original channel estimation of the multiple cells, and the real channel estimation of the search cell and other multiple cells is obtained; performing joint detection by using the channel estimation and a zero forcing algorithm or a maximum likelihood estimation algorithm to obtain data of a main common control channel; and then the carrier frequency is accurately adjusted by using the data. Since the carrier frequency offset is gradually reduced after each adjustment, the frequency fine adjustment requires a plurality of processes to meet the system requirement, for example, the system requires the carrier frequency offset to be within 200 hz.
When the phase confirmation of the landing cell is carried out, firstly, data containing training sequence codes of a time slot 0 are received, and channel estimation is carried out by utilizing basic training sequence codes of a search cell and multi-cell training sequence codes in a list to obtain the original channel estimation of the multi-cell; then, the mutual interference elimination is carried out on the original channel estimation of the multiple cells, and the channel estimation after the interference elimination of the search cells is obtained; and carrying out convolution on the impulse response and the downlink synchronous code used by the landing cell, comparing the obtained sequence with the received data containing the downlink synchronous code part, and obtaining the modulation phase of the downlink synchronous code of the subframe. According to the TD-SCDMA system feature, the phase is dedicated to indicating system information interleaved frames. So that after several consecutive phases are obtained, interleaved frames of system information can be detected.
When the system information of the login cell is read, the data of the time slot 0 of an interleaving frame is received from an interleaving frame header according to the determined interleaving frame of the main common control channel, for example, 20 milliseconds and 4 TD-SCDMA subframes. And carrying out data demodulation on a code channel 0 and a code channel 1 for the time slot 0 data of each subframe. Firstly, performing channel estimation by using a basic training sequence code of a login cell and a multi-cell training sequence code in a list to obtain the original channel estimation of the multi-cell; eliminating mutual interference of the original channel estimation of the multiple cells to obtain real channel impulse response of the search cell and other multiple cells; then, a joint detection algorithm, for example, a zero forcing algorithm or a maximum likelihood algorithm, is used for data detection to obtain data of the subframe code channel 0 and the code channel 1; and inputting the data of the 4 subframes into a channel decoding unit to obtain the information of the main common control channel, namely the system information of the login cell.
In the invention, the terminal can utilize the obtained multi-cell information to search the cell by adding the multi-cell selection module and the multi-cell confirmation module in the TD-SCDMA terminal, thereby improving the probability of successfully logging in the cell by the terminal.
The invention also provides a cell search method of the TD-SCDMA terminal in the same frequency network, as shown in FIG. 3, comprising the following steps:
step 201, the TD-SCDMA terminal performs downlink pilot time slot position synchronization.
In this step, the TD-SCDMA terminal performs downlink pilot time slot position synchronization, which includes two processes, that is, coarse position synchronization of the downlink pilot time slot and precise position synchronization of the downlink pilot time slot.
In the course of rough position synchronization of the downlink pilot time slot, it can be known from the structure characteristics of the TD-SCDMA frame that the power of the downlink synchronization code sent in the downlink pilot time slot in each sub-frame is much higher than the power of the front and back guard symbols, so that a power characteristic window can be set by using the power structure characteristics of this sub-frame, and the rough position of the downlink pilot time slot can be found through the power characteristic window. For example: the length of the power characteristic window is set to be 8 symbols, and the sum of the powers of the middle 4 symbols is divided by the sum of the powers of the two sides which are the total of 4 symbols, so that the ratio of the power characteristic window can be obtained. And calculating the same power characteristic window ratio of the received whole sub-frame data and performing sliding comparison, finding the maximum value in all the power characteristic window ratios, wherein the position corresponding to the maximum value is the rough position of the downlink pilot frequency time slot in the sub-frame. The accuracy of determining the rough position of the downlink pilot time slot depends on the interval selected when the power characteristic window slides, and the shorter the interval is, the higher the accuracy of determining the rough position of the downlink pilot time slot is. The rough position of the downlink pilot frequency time slot determined by the method can reach the precision of 1 symbol level.
On the basis of the coarse position synchronization of the downlink pilot time slot, the terminal can receive a segment of data containing a downlink synchronization code, and the precise position synchronization of the downlink pilot time slot is performed based on the data. The process of the accurate position synchronization of the downlink pilot frequency time slot comprises the following steps: performing matching processing on all downlink synchronous codes one by using data containing the downlink synchronous codes, and performing matched filtering on each downlink synchronous code and the data to obtain a group of matched filtering related power values; selecting a maximum value from each group of matched related power values and recording a corresponding position; if the maximum value is greater than the preset threshold, the maximum value is the measured value corresponding to the downlink synchronous code. The measured values and corresponding positions of all downlink synchronous codes can be obtained through the processing, and simultaneously the downlink pilot frequency time slot is synchronously adjusted according to the position corresponding to the downlink synchronous code with the largest measured value in all the downlink synchronous codes, and the accuracy of 1 chip can be achieved after the adjustment.
Step 202, according to the downlink pilot time slot position synchronization result, performing multi-cell selection to obtain a multi-cell list including downlink synchronization code information and corresponding code power values.
In the step 201, the measured values and corresponding positions of the downlink synchronization codes of all cells may be output, and then, in this step, multi-cell selection is performed according to the output result of the step 201.
As shown in fig. 4, the process of selecting a multi-cell includes the following steps:
step a1, selecting the largest measured value from the measured values of the code power corresponding to the downlink synchronization codes of all cells and recording the corresponding downlink synchronization codes.
Step A2, comparing the code power measurement value of the downlink synchronous codes of the other cells with the difference between the maximum code power measurement value and the set threshold value, selecting the corresponding cell with the downlink synchronous code power measurement value greater than the difference value, and recording the downlink synchronous codes and the corresponding code power in the multi-cell list.
Step a3, the multi-cell list is sorted according to the size of the code power.
Through the sorting process, a multi-cell list sorted according to the size of the code power measured value can be obtained, and the list comprises the downlink synchronous code information and the corresponding code power.
Step 203, according to the multi-cell list information, carrier frequency adjustment and multi-cell basic training sequence code/scrambling code confirmation are performed.
In this step, the carrier frequency offset is estimated and adjusted according to the information of the multi-cell selected in step 202, that is, according to the multi-cell list information. In this step, the TD-SCDMA terminal first needs to receive a segment of data containing downlink synchronization codes; then, carrier frequency deviation estimation is carried out by respectively using the downlink synchronous code of the cell to be searched and the downlink synchronous code of the multi-cell, most probable analysis is carried out on the estimation result, the frequency deviation estimation value with stronger relativity is weighted and averaged, and the weight can be determined according to the code power measurement value of the downlink synchronous code in the multi-cell list; and finally, obtaining a final frequency deviation value and performing control adjustment. This process needs to be performed several times to meet the target that the carrier frequency deviation value reaches the set range, for example, the carrier frequency deviation value is less than 1kHz after several adjustments.
After the accurate position of the downlink pilot time slot is synchronized, the TD-SCDMA terminal can find the training sequence part data of the time slot 0. And respectively correlating 4 basic training sequence codes/scrambling codes corresponding to each downlink synchronous code with the received training sequence data of the time slot 0 to calculate the correlation power. For the search cell, the basic midamble code/scrambling code corresponding to the maximum correlation power value is the basic midamble code/scrambling code used by the search cell. The search cell is also a landing cell described later.
Step 204, confirming the basic training sequence codes/scrambling codes of the multiple cells to obtain a multiple cell list containing the relevant power value of each cell and the corresponding basic training sequence codes/scrambling codes.
As shown in fig. 5, the method for identifying the basic midamble codes/scrambling codes of multiple cells includes the steps of:
step B1, comparing the correlation power of the basic training code/scrambling code of each cell is larger than the difference value between the correlation power value corresponding to the basic training sequence code/scrambling code of the landing cell and a threshold.
In this step, the input data for decision includes the relevant power values of all basic training sequence codes/scrambling codes in the multi-cell list obtained by the multi-cell selection, the relevant power values corresponding to the basic training sequence codes/scrambling codes of the login cell, and a preset threshold. The relative power of the basic training code of each cell is compared with the difference value between the relative power of the landing cell and a set threshold.
And step B2, selecting the cell corresponding to the basic training sequence code/scrambling code with the correlation power larger than the difference value as the interference cell.
And step B3, sorting the selected multiple cells according to the related power to obtain a multiple cell list.
Through the step, a multi-cell list containing the relevant power value of each cell and the corresponding basic training sequence code/scrambling code can be obtained.
Step 205, according to the relevant power value of each cell in the multi-cell list and the corresponding basic training sequence code/scrambling code, performing carrier frequency precision adjustment, login cell phase confirmation, and login cell system information reading.
In this step, when the frequency is precisely adjusted, the carrier frequency offset estimation is mainly performed by using the data of the primary common control channel on the time slot 0 in the frame structure.
The specific process is as follows: first, data of the whole time slot 0 is received, and the time slot 0 is jointly detected. When channel estimation of joint detection is carried out, channel estimation needs to be carried out by using a basic training sequence code of a search cell and a multi-cell training sequence code in a multi-cell list, and original channel estimation of multiple cells is obtained; then, the mutual interference elimination is carried out on the original channel estimation of the multiple cells, and the real channel estimation of the search cell and other multiple cells is obtained; performing joint detection by using the channel estimation and a zero forcing algorithm or a maximum likelihood estimation algorithm to obtain data of a main common control channel; and then the carrier frequency is accurately adjusted by using the data. Since the carrier frequency offset is gradually reduced after each adjustment, the frequency fine adjustment requires a plurality of processes to meet the system requirement, for example, the system requires the carrier frequency offset to be within 200 hz.
In the step, when the phase confirmation of the landing cell is carried out, firstly, the data of a time slot 0 containing the training sequence codes is received, and the basic training sequence codes of the search cell and the multi-cell training sequence codes in the list are utilized to carry out channel estimation to obtain the original channel estimation of the multi-cell; then, the mutual interference elimination is carried out on the original channel estimation of the multiple cells, and the channel estimation after the interference elimination of the search cells is obtained; and performing convolution on the impulse response and the downlink synchronous code used for logging in the cell, comparing the obtained sequence with the received data containing the downlink synchronous code part, and obtaining the modulation phase of the downlink synchronous code of the corresponding subframe. According to the TD-SCDMA system feature, the phase is dedicated to indicating system information interleaved frames. So that after several consecutive phases are obtained, interleaved frames of system information can be detected.
In this step, when reading the system information of the landing cell, the data of the time slot 0 of an interleaved frame is received from an interleaved frame header according to the above-identified interleaved frame of the primary common control channel, for example, 20 ms, 4 TD-SCDMA subframes.
And carrying out data demodulation on a code channel 0 and a code channel 1 for the time slot 0 data of each subframe. Firstly, performing channel estimation by using a basic training sequence code of a login cell and a multi-cell training sequence code in a list to obtain the original channel estimation of the multi-cell; eliminating mutual interference of the original channel estimation of the multiple cells to obtain real channel impulse response of the search cell and other multiple cells; then, a joint detection algorithm, for example, a zero forcing algorithm or a maximum likelihood algorithm, is used for data detection to obtain data of the subframe code channel 0 and the code channel 1; and inputting the data of the 4 subframes into a channel decoding unit to obtain the information of the main common control channel, namely the system information of the login cell.
And the terminal finishes the initial cell search according to the multi-cell information. Compared with the prior art, the terminal can detect the same-frequency multi-cell information including the downlink synchronous codes, the corresponding code power and the basic training sequence codes/scrambling codes of each cell as early as possible in the initial cell searching stage, and then accurately adjust the frequency of the logged-in cell, judge the phase of the logged-in cell and read the system information of the logged-in cell by using the detected multi-cell information, so that the interference caused by the same-frequency multi-cell during the logged-in of the terminal, which cannot be overcome in the prior art, is eliminated, and the success rate of initial cell searching is improved.
While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.
Claims (17)
1. A TD-SCDMA terminal, including central processing unit and function module, characterized by that, also include many cell selection module and many cell confirm the module;
the multi-cell selection module is used for performing multi-cell selection according to the downlink pilot frequency time slot position synchronization result to obtain a multi-cell list containing downlink synchronization code information and corresponding code power measurement value information;
the TD-SCDMA terminal adjusts the carrier frequency and confirms the basic training sequence code/scrambling code of the multi-cell according to the multi-cell list information;
the multi-cell confirming module is used for confirming basic training sequence codes/scrambling codes of the multi-cell to obtain a multi-cell list containing the relevant power value of each cell and the corresponding basic training sequence codes/scrambling codes;
and the TD-SCDMA terminal performs carrier frequency precise adjustment, cell login phase confirmation and cell login system information reading according to the relevant power value of each cell in the multi-cell list obtained by the multi-cell confirmation module and the corresponding basic training sequence code/scrambling code.
2. The TD-SCDMA terminal according to claim 1, wherein the multi-cell selection module selects the largest measured value from the measured values of the code powers corresponding to the downlink synchronization codes of all the cells and records the corresponding downlink synchronization code, compares the measured values of the code powers corresponding to the downlink synchronization codes of the other cells with the difference between the largest measured value of the code power and the set threshold value, selects the corresponding cell whose measured value of the code power of the downlink synchronization code is greater than the difference, records the downlink synchronization code of the selected cell and the measured value of the corresponding code power in the multi-cell list, and then sorts the multi-cell list according to the measured value of the code power.
3. The TD-SCDMA terminal according to claim 1, characterized in that the multi-cell confirmation module compares the correlation power of the basic training code/scrambling code of each cell with the difference between the correlation power value corresponding to the basic training sequence code/scrambling code of the landing cell and a threshold; selecting the cell corresponding to the basic training sequence code/scrambling code with the correlation power larger than the difference value as an interference cell; and sequencing the selected multiple cells according to the related power to obtain a multiple cell list.
4. A cell search method of TD-SCDMA terminal under the same frequency network is characterized in that the steps include:
step one, a TD-SCDMA terminal carries out downlink pilot frequency time slot position synchronization;
step two, selecting multiple cells according to the downlink pilot frequency time slot position synchronization result to obtain a multiple cell list containing downlink synchronization code information and corresponding code power values;
step three, carrier frequency adjustment and multi-cell basic training sequence code/scrambling code confirmation are carried out according to the multi-cell list information;
confirming the basic training sequence codes/scrambling codes of the multiple cells to obtain a multiple cell list containing the relevant power value of each cell and the corresponding basic training sequence codes/scrambling codes;
and fifthly, carrying out carrier frequency precise adjustment, login cell phase confirmation and login cell system information reading according to the relevant power value of each cell in the multi-cell list and the corresponding basic training sequence code/scrambling code.
5. The cell search method of claim 4, wherein in the first step, the terminal performs coarse position synchronization of the downlink pilot time slot and fine position synchronization of the downlink pilot time slot in sequence.
6. The cell search method of claim 5, wherein in the first step, the method for performing coarse position synchronization of downlink pilot time slots comprises: and carrying out the same power characteristic window ratio calculation and sliding comparison on the received whole subframe data, finding out the maximum value from all the power characteristic window ratios, wherein the position corresponding to the maximum value is the rough position of the downlink pilot frequency time slot in the subframe.
7. The cell search method of claim 5, wherein in the first step, the method for performing the precise position synchronization of the downlink pilot time slot comprises: performing matching processing on all downlink synchronous codes one by using data containing the downlink synchronous codes, and performing matched filtering on each downlink synchronous code and the data to obtain a group of matched filtering related power values; selecting a maximum value from each group of matched related power values and recording a corresponding position; if the maximum value is larger than the preset threshold, the maximum value is the measured value corresponding to the downlink synchronous code; the measured values and corresponding positions of all downlink synchronous codes can be obtained through the processing, and the downlink pilot frequency time slot is synchronously adjusted according to the position corresponding to the downlink synchronous code with the largest measured value in all the downlink synchronous codes.
8. The cell search method of claim 4, wherein in the second step, the step of multi-cell selection comprises:
step A1, selecting the largest measured value from the measured values of the code power corresponding to all the cell downlink synchronous codes and recording the corresponding downlink synchronous codes;
step A2, comparing the code power measurement value of the downlink synchronous codes of other cells with the difference between the maximum measurement value of the code power and the set threshold value, selecting the corresponding cell with the downlink synchronous code power measurement value greater than the difference value, and recording the downlink synchronous codes and the corresponding code power in a multi-cell list;
step a3, the multi-cell list is sorted according to the size of the code power.
9. The method for cell search according to claim 4, wherein in the third step, the method for adjusting the carrier frequency comprises: the TD-SCDMA terminal receives a segment of data containing downlink synchronous codes at first; then, carrier frequency deviation estimation is carried out by respectively using the downlink synchronous code of the cell to be searched and the downlink synchronous codes of the multiple cells, most probable analysis is carried out on the estimation result, and the frequency deviation estimation value with stronger relativity is weighted and averaged; and finally, obtaining a final frequency deviation value and performing control adjustment.
10. The cell search method according to claim 9, wherein the weight value for performing the weighted average is determined according to a code power measurement value of a downlink synchronization code in a multi-cell list obtained by multi-cell selection.
11. The method for cell search according to claim 4, wherein in the third step, the method for multi-cell primary midamble code/scrambling code confirmation is: and respectively correlating the basic training sequence code/scrambling code corresponding to each downlink synchronous code with the received training sequence data of the corresponding time slot, and calculating the correlation power, wherein the basic training sequence code/scrambling code corresponding to the maximum value of the correlation power is the basic training sequence code/scrambling code used by the search cell.
12. The cell search method of claim 4, wherein in the fourth step, the step of multi-cell acknowledgement comprises:
step B1, comparing the correlation power of the basic training code/scrambling code of each cell with the difference between the correlation power value corresponding to the basic training sequence code/scrambling code of the landing cell and a threshold;
step B2, selecting the cell corresponding to the basic training sequence code/scrambling code whose correlation power is larger than the difference value as the interference cell;
and step B3, sorting the selected multiple cells according to the related power to obtain a multiple cell list.
13. The cell search method of claim 4, wherein in the fifth step, the method for precisely adjusting the frequency comprises: receiving data of a corresponding time slot, and carrying out joint detection on the time slot to obtain data of a main common control channel; and then the carrier frequency is accurately adjusted by using the data.
14. The cell search method according to claim 13, wherein in performing channel estimation for joint detection, channel estimation is performed using a basic training sequence code of a search cell and multi-cell training sequence codes in a multi-cell list to obtain original channel estimation of the multi-cell; then, the mutual interference elimination is carried out on the original channel estimation of the multiple cells, and the real channel estimation of the search cell and other multiple cells is obtained; and then the real channel estimation is utilized to carry out the joint detection.
15. The cell search method of claim 14, wherein the obtained true channel estimates are jointly detected using a zero-forcing algorithm or a maximum likelihood estimation algorithm.
16. The cell search method of claim 4, wherein in the fifth step, the method for confirming the landing cell phase comprises: firstly, receiving data containing training sequence codes of corresponding time slots, and performing channel estimation by using basic training sequence codes of a search cell and multi-cell training sequence codes in a list to obtain original channel estimation of the multi-cell; then, the mutual interference elimination is carried out on the original channel estimation of the multiple cells, and the channel estimation after the interference elimination of the search cells is obtained; and performing convolution on the impulse response and the downlink synchronous code used for logging in the cell, comparing the obtained sequence with the received data containing the downlink synchronous code part, and obtaining the modulation phase of the downlink synchronous code of the corresponding subframe.
17. The cell search method of claim 4, wherein in the fifth step, the method for reading the system information of the logged-in cell comprises: firstly, carrying out basic training sequence codes of a login cell and multi-cell training sequence codes in a list to obtain original channel estimation of multiple cells; then, the mutual interference elimination is carried out on the original channel estimation of the multi-cell, and the real channel impulse response of the searching cell and other multi-cells is obtained; then, carrying out data detection by using a joint detection algorithm to obtain data of a code channel corresponding to a subframe; and finally, inputting the data of the corresponding sub-frame into a channel decoding unit to obtain the system information of the login cell.
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