Title of Invention

A GAIN CONTROL METHOD FOR THE INITIAL CELL SEARCHING IN TD-SCDMA MOBILE COMMUNICATION SYSTEM

Abstract The present invention relates to, a pain control method for user terminal employed when cell perform initial searching in a TD-SCDMA mobile communication system. First, the user terminal receive and record data of plurality of subframe by BS transmitted in the case of receiver have maximum gain for each carrier frequency; Search the position of Downlink Pilot Times Slot (DwPTS) of plurality of subframe using time window determine method; Continue perform later process of cell initial searching when acquired the position of DwPTS; Determine whether receiver is saturated when not acquired the positon of DwPTS; lf receiver is saturated, decrease gain of receiver and continue receive and record data of plurality of subframe by BS transmitted; If receiver is not saturated, determine no BS adapt to currently carrier frequency. Repeat perform above discribed cell initial searching process, until the receiver is not saturated. The present invention can speedy complete cell initial searching in the condition of ADC of user terminal in a limit dynamic range
Full Text FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See section 10, rule 13)
'A GAIN CONTROL METHOD OF WHEN CELL PERFORM INITIAL SEARCHING IN A TD-SCDMA MOBILE COMMUNICATION SYSTEM'
DA TANG MOBILE COMMUNICATIONS EQUIPMENT CO. LTD., Beijing 100083, China,



The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention relates generally to a mobile communication technology, and more particularly to a gain control method for the initial cell searching in a TD-SCDMA mobile communication system.
BACKGROUND OF THE INVENTION
The cell searching has to be performed whenever all user terminals in the mobile communication system are powered on or the cell is re-selected. Accordingly, a method for cell searching is provided in the standarded of Third Generation Mobile Communication System.
Take TD-SCDMA system as an example in TDD (Time Division Duplex) system to describe its frame structure before introducing the cell searching method. FIGURE 1 is a schematic diagram illustrating the frame structure in TD-SCDMA system and the cell searching therein. A TD-SCDMA signal is composed of periodic time units on the basis of time. A basic time unit is regarded as a "wireless frame" (a frame) of 10ms in length; each "wireless frame" can be divided into two subframes of 5ms in length; each subframe is further divided into seven regular time slots TS0-TS6 and three special time slots located between TSO and TS1, wherein, the traffic is transferred in the regular time slots and three special time slots include DwPTS (Downlink Pilot Time Slot), UpPTS (uplink Pilot Time Slot) and the Guard band (G). According to TD-SCDMA standard, TSO is usually designated as the Downlink direction, and TS1 is usually designated as the Uplink direction.
The cell searching procedure comprises steps as follows: firstly, the data of one subframe is received at the working carrier frequency and performing AGC (Automatic Gain Control) is immediately followed, so that the maximum level of the signal received within the time of the subframe (T=0 ms to T=5 ms) will not cause saturation of the receiver (located between the minimum receiving level and the saturation level of the receiver as shown in the figure); secondly, the DwPTS position is acquired by detecing a sliding time window point-by-point, e.g., the arrival time t0 as shown in the figure, based
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on the structure of the TD-SCDMA frame having no transmission power in the guard time before and after DwPTS, and the downlink synchronization and carrier tracking according to the timing of said DwPTS are acquired; finally, BCCH (Broadcast Control Channel) information is received and read in TSO time slot until the cell searching is completed.
The time window decision method can be adopted to acquire the DwPTS position by detecing a sliding time window point-by-point. The time window decision method includes: to determine the length of the sliding time window as eight symbols based on the feature that the DwPTS code length is fixed as four symbols, and to judge the DwPTS position according to the criterion that the levels of the four middle symbols are higher than that of the two symbols at two sides thereof.
In practical user terminals, the dynamic range of the receiver is limited, therefore, the receiver usually uses the automatic gain control technology. As the cell searching begins, the receiver performs the automatic gain control immediately after receiving a subframe data to ensure that the maximum level of signal (including interference) in the received subframe will not cause saturation of the receiver. In FIGURE I, the vertical line areas represent the level of the received downlink signal from the base station, and the horizontal line areas represent the level of the received uplink signal of other working user terminals.
FDD (Frequency Division Duplexing) system adopts different working carrier frequencies in receiving and transitting, and TDD (Time Division Duplexing) system only uses one carrier frequency, i.e., a same carrier frequency is adopted in receiving and transmitting. The normal AGC manner is adopted to ensure that the level of the signal in the received subframe at the terminal does not cause saturation of the receiver as the automatic gain control is performed immediately, which, however, will not only make the cell initial searching difficult but also lead failure of it when the following situation: the user terminal performing the cell searching will receive not only the downlink signal from the base station but also the uplink signal of other working user terminals, what is more, if the user terminal locates around the border of the cell which adopts a plurality of same carrier frequencies for working, it will also receive the downlink signal of the base station
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in neighbouring cells as well as the uplink signal of the working user terminals in said neighbouring cells; if one or more user terminals in the vicinity of the user terminal performing the cell searching are calling, and their working frequencies are same, the uplink signal from the user terminal may be far higher than the downlink signal from the base station. The presence of the interference makes the cell searching more difficult in TDD system.
To solve the above problems, the common way is adopted to increase the receiving dynamic range of the receiver nowadays, and ADC (Analog-to-Digital Converter) with more bits must be used accordingly, which leads a high cost of the device. Moreover, the working voltage of the user terminal is very low, the ADC bits being used are difficult to exceed ten bits, and the dynamic range is difficult to exceed 60dB. Therefore, it is impossible to realize the object of increasing the desired dynamic range of the receiver.
In a practical mobile communication network, the AGC range of the receiver at TD-SCDMA user terminal can exceed 80dB, but it is only 60dB at a certain gain (assuming using ADC with 10 bit accuracy). Several cases are hereinafter described in conjunction with FIGURE 2 to illustrate the problems that occur in the initial cell searching when adopting said normal automatic gain control method.
FIGURE 2A shows a typical case. In a subframe (5ms), the user obtains the downlink signal mainly from the base station which is indicated by the vertical line areas, and the signal of other working users is very low. A good receiving effect can be obtained and the initial cell searching can be realized easily once the aforementioned normal automatic gain control technogoly is used. The block area indicates the thermal noise level as shown in FIGURE 2.
FIGURE 2B shows a case that a user is located far from the base station and another working user is nearby. When another working user terminal (indicated by the horizontal line area in the figure) exists in the vicinity of a user (indicated by the vertical line area), and the signal level of said another working user terminal may reach -30dB or more, the gain control is adjusted immediately to be capable of receiving the signal level of the subframe (5ms) normally not to lead saturation of the receiver if the normal AGC
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technology is employed. Meanwhile, the signal (DwPTS in the figure) is lower than the noise (ADC quantification noise level indicated by the shadow in the figure) due to the limitation of the ADC sampling accuracy, which leads failure of the initial cell searching.
FIGURE 2C shows a case that a user locates at the edge of the cell and there are interferences from neighbouring cells. Alough there is no interference of neighbouring users, the interference from neighbouring cells is severe when the user locates at the edge of a cell, and SNR is very low. The base stations in neighbouring cells are synchronized, so the present positions of DwPTS of the subframes in respective cells are adjacent to each other, e.g., DwPTS in different cells as shown in the figure. However, the increase of the width of DwPTS received by the user is not large, and the feature that both guards of DwPTS are still exists. Therefore, the cell searching is difficult to be carried out, but can be realized when adopting the normal AGC technology.
The last possible case is the combination by those shown in FIGURE 2B and FIGURE 2C. For the same reason as shown in FIGURE 2B the initial cell searching will definitely be a failure.
In conclusion, when the initial cell searching is performed, the user terminal performs the automatic gain control immediately when receiving a subframe signal, therefore, it is difficult to realize the initial cell searching in the case of other working user terminals being in the vicinity of said user terminal, which may even lead failure of the cell searching.
SUMMARY OF THE INVENTION
The object of the present invention is to design a gain control method for the initial cell searching in TD-SCDMA mobile communication system, and the gain control method is used for the initial cell searching at the user terminal to solve the problems that the initial cell searching is difficult to be performed in the part of the background description as shown in FIGURE 2, and to complete the initial cell searching rapidly under the condition of limited dynamic range by using the user terminal ADC.
The technical solution to realize the object of the present invention is a gain control method for the initial cell searching in TD-SCDMA mobile communication system, said
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gain control method comprising:
Step A: the user terminal receiving data in the maximum receiving gain at the selected carrier frequency;
Step B: recording the received data of a plurality of subframes;
Step C: determining the DwPTS position of each received subframe by using the time window decision method;
Step D: performing the succeeding procedure of the initial cell searching and returning to execute Step A subsequently when the DwPTS positions of the most received subframes can be determined, and executing Step E when the DwPTS positions of the most received subframes can not be determined; and
Step E: judging whether the receiver is in saturation, wherein, returning to execute Step A subsequently when the receiver is not in saturation, and decreasing the receiving gain by a step length and returning to execute Step B subsequently when the receiver is in saturation.
After the procedure returning to execute Step A subsequently in Step D and Step E, Step A re-selects another carrier frequency from all possible carrier frequencies until every possible carrier frequency is selected and then ends the initial cell searching.
Step D judges whether the DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes are determined so as to determine that the DwPTS positions of the most received subframes can be determined, and judges whether the DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes are not determined so as to determine that the DwPTS positions of the most received subframes can not be determined.
Said DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes are determined continuously or at intervals.
In Step D, said determined DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes are considered as the DwPTS positions of subframes.
In Step E, if the receiver is not judged as in saturation and the received signal is
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environmental interference, there is no base station for working at present carrier frequency.
In Step E, the receiving gain is decreased by a step length ranging from 6dB to 24dB.
The present invention is applicable to TD-SCDMA mobile communication system, and relates to a gain control method being used for the initial cell searching at the user terminal. When the user terminal begins with the initial cell searching, the receiver gain is set to be maximum without considering whether the receiver is in saturation; the received data of a plurality of subframes are recorded, then the DwPTS positions of respective subframe are determined using the time window decision method based on the structure feature of the TD-SCDMA system frame; the receiver gain is decreased by a larger step length when acknowledging that the receiver is in saturation and the DwPTS positions can not be obtained; and the data of a plurality of subframes are recorded continuously in every cycle, and the receiver gain is decreased gradually unitl the receiver is not in saturation any more. The final result after the procedure may be that the DwPTS position is determined for every possible carrier frequency based on the structure of the TD-SCDMA system frame; or no base station exists for being accessed on certain carrier frequency.
The method of the present invention is implemented repeatedly on every possible carrier frequency, and finally completes the initial cell searching.
The method of the present invention can greatly enhance the success rate of the initial cell searching of the user terminal. The ADC of user terminals can complete the initial cell searching under the condition of limited dynamic range, so the bit demand for ADC can be lowered, i.e., decreasing the device cost. Therefore, the problem that the initial cell searching is hard to be implemented when another working terminal exists in the vicinity of a user terminal can be solved.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a schematic diagram illustrating the frame structure and the cell searching in TD-SCDMA mobile communication system;
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FIGURE 2 is a schematic diagram illustrating several cases of a subframe signal received at the initial cell searching comprising a typical case as shown in FIGURE 2A, a case that a user is located far from the base station and another working user is nearby as shown in FIGURE 2B, and a case that a user locates at the edge of the cell and there are interferences from neighbouring cells as shown in FIGURE 2C.
FIGURE 3 is a flowing chart illustrating the gain control procedure at the cell searching.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is hereinafter described in conjunction with the drawings.
In TD-SCDMA system, its frame structure is designed with spectial downlink pilot time slot (DwPTS). As shown in FIGURE I, there is not any interference from the cell or the sector but from neighbouring cells or another mobile communication system in said time slot and its neighbouring time instead. In other words, the user terminal can receive the downlink pilot signal more accurately and by which the initial cell searching is realized in said DwPTS time slot. Furthermore, the level of said downlink pilot signal is equivalent to or higher than that on BCCH, which is one of important characteristics of the TD-SCDMA standard.
The present invention realizes simply and effectively the gain control when TD-SCDMA system terminal performs the initial cell searching by said characteristics. The method disclosed in the present invention can solve basically the problems occurred in the initial cell searching.
With reference to FIGURE 3, the gain control method adopted at the initial cell searching is illustrated.
The user terminal begins with the initial cell searching (Step 301); sets the original carrier frequency and the maximum gain of the receiver (Step 302); receives and records signals of a plurality of subframe by the original carrier frequency and the maximum gain of the receiver (Step 306); and searches the DwPTS positions of a plurality of subframes using the aforementioned time window decision method according to the structure feature of TD-SCDMA frame, and then different results are produced (Step 307 and 308) based
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on the search of the DwPTS positions of a plurality of subframes:
The first result is to perform the succeeding procedure of the initial cell searching continuously, including receiving and reading the BCCH information in TSO time slot, after judging that the DwPTS positions of a plurality of subframes have been found and finished the initial cell searching (Step 309);
The second result is to further judge that the received signal does not cause the receiver to be in saturation (Step 310) when judging that the DwPTS positions of a plurality of subframes have not been searched, therefore, it can be determined that the level of the received signal is very low or the received signal is environmental interference; and there is no base station for working at the present carrier frequency, then, the carrier frequency is changed, the maximum gain of the receiver is adopted (Step 304), and next initial cell searching is re-performed (Step 302);
The third result is to decrease the receiving gain of the receiver by a large step length (Step 311), which normally can be selected from 6dB to 24dB, e.g., 6, 9, 12, 24dB, in the case that the DwPTS positions of respective subframes can not be obtained and the received signal level causes the receiver to be in saturation, and then to re-receive and record the received signals of a plurality of subframes at the present carrier frequency (Step 306).
The receriver gain is decreased by a step length once the received signal level causes the receiver to be in saturation, i.e., the data received within a part of time reaches the highest bit in the ADC dynamic range (the part of time is a time period within 5ms, which can be smaller than 1ms or several ms). Then, the signals of several subframes at the present carrier frequency are re-received and recorded, and the initial cell searching is re-performed (Step 307). The procedure is repeated for several times until the receiver is not saturated. The DwPTS positions may be searched successfully in the repeating procedures, and the process goes into the succeeding procedure (Step 309), but an instance may occur that the DwPTS positions still can not be obtained, therefore, it is determined that there is no base station for working at the present carrier frequency (Step 312). Then, the present carrier frequency is changed (Step 304), and the initial cell
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searching is re-performed (Step 302) wherein, the present carrier frequency is changed from all possible carrier frequencies. The initial cell searching procedure is completed until the above procedure has been executed at all carrier frequencies (Step 315 and 316).
The initial cell searching procedure of the terminal can be completed effectively by such a control of the receiver gain. The cell searching is executed at all possible carrier frequencies and the cell searching in all cells are completed finally.
It should be noted that the received signal of a plurality of subframes are recorded continously or at intervals in each initial cell searching (Step 306), and the DwPTS positions are searched for the signal of each subframe in the method of the present invention. The condition that the DwPTS positions are found in the most subframes, e.g., more than half of subframes, is considered as a criterion for obtaining the DwPTS positions in Step 308, and the DwPTS positions found in more than half of subframes are considered as the DwPTS positions. In this manner, the present invention can overcome the influence of fast fading and improve the success rate of the initial cell searching completed in the case of SNR being very low (approaching OdB).
The method of the present invention applied to TD-SCDMA mobile communication system is a gain control method used at the initial cell searching for the user terminal. At each carrier frequency, the receiver is set at the maximum receiving gain to receive and record the received data of a plurality of subframes; the time window decision method is used to search the DwPTS positions of a plurality of subframes transmitted by the base station, and the receiver gain is decreased by a large step length when determined as the receiver is in saturation and the DwPTS positions can not be obtained; and the receiver gain is decreased gradually when repeating above cell searching procedures until the receiver is not in saturation any more. The ADC of user terminals can complete the initial cell searching under the condition of less dynamic range by using the present invention.
According to an embodiment of the present invention, a TD-SCDMA mobile communication system has a gain controller for the initial cell searching, said system comprises:
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a receiver at the user terminal for receiving data in the maximum receiving gain at the selected carrier frequency;
a selecting means for selecting a first carrier frequency;
a recorder for recording the received data of a plurality of subframes;
a determining unit for determining the DwPTS position of each received subframe by using the time window decision method;
an executing means configured to perform the succeeding procedure of the initial cell searching;
a decision making unit configured to judge whether the receiver is in saturation;
a decrementing means configured to decrease the receiving gain by a step length;
a terminating means configured to end the initial cell searching;
wherein the executing means is configured to perform the succeeding procedure of the initial cell searching wherein the executing means connects to the receiver subsequently when the DwPTS positions of the most received subframes is determined, and the executing means connects to the decision maker when the DwPTS positions of the most received subframes is not determined;
wherein the decision making unit is configured to judge whether the receiver is in saturation and when the receiver is not in saturation, the decrementing means decreases the receiving gain by a step length and then the decrementing means connects to the receiver, and subsequently when the receiver is in saturation, the decrementing means connects to the recorder.
According to yet another embodiment of the present invention, the TD-SCDMA mobile communication system has a gain controller for the initial cell searching, wherein the selecting means is configured to select a carrier frequency succeeding the previously selected carrier frequency until each possible carrier frequency is selected before the executing means or the decrementing means connects to the receiver; and a terminating means is configured to end the initial cell searching.
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According to still another embodiment of the present invention, the TD-SCDMA mobile communication system has a gain controller for the initial cell searching, wherein the determining means comprises;
a judging means configured to judge whether the DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes need to be determined so that the determining means determines the DwPTS positions of the most received subframes.
According to still another embodiment of the present invention, the TD-SCDMA mobile communication system has a gain controller for the initial cell searching, wherein;
the determining means is configured to determine continuously or at intervals, the DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes.
According to still another embodiment of the present invention, the TD-SCDMA mobile communication system has a gain controller for the initial cell searching, wherein;
the determining means is configured to determine the DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes and then the said determined DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes are considered as the DwPTS positions of subframes.
According to still another embodiment of the present invention, the TD-SCDMA mobile communication system has a gain controller for the initial cell searching, wherein the decision making unit comprises;
a judging means configured to judge whether the receiver is in saturation or not and the received signal is environmental interference, and if the receiver is judged not to be in saturation, then there is no base station for working at present carrier frequency.
According to still another embodiment of the present invention, the TD-SCDMA mobile
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communication system has a gain controller for the initial cell searching, wherein;
the decrementing means is configured to decrease the receiving gain by a step length ranging from 6dB to 24dB.
13

WE CLAIM;
1. A gain control method for the initial cell searching in TD-SCDMA mobile
communication system, said gain control method comprising:
Step A: the user terminal receiving data in the maximum receiving gain at the selected carrier frequency;
Step B: recording the received data of a plurality of subframes;
Step C: determining the DwPTS position of each received subframe by using the time window decision method;
Step D: performing the succeeding procedure of the initial cell searching and returning to execute Step A subsequently when the DwPTS positions of the most received subframes can be determined, and executing Step E when the DwPTS positions of the most received subframes can not be determined; and
Step E: judging whether the receiver is in saturation, wherein, returning to execute Step A subsequently when the receiver is not in saturation, and decreasing the receiving gain by a step length and returning to execute Step B subsequently when the receiver is in saturation.
2. A gain control method for the initial cell searching in TD-SCDMA mobile
communication system as defined in claim 1, wherein
after said method returning to execute Step A subsequently in Step D and Step E, Step A re-selects another carrier frequency from all possible carrier frequencies until each possible carrier frequency is selected and then ends the initial cell searching.
3. A gain control method for the initial cell searching in TD-SCDMA mobile
communication system as defined in claim 1, wherein
in Step D, judging whether the DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes are determined so as to determine that the DwPTS positions of the most received subframes can be determined; and in Step D, judging whether the DwPTS positions whose number exceeds half of the
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total number of DwPTS positions in the received subframes are not determined so as to determine that the DwPTS positions of the most received subframes can not be determined.
4. A gain control method for the initial cell searching in TD-SCDMA mobile
communication system as defined in claim 3, wherein
said DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes are determined continuously or at intervals.
5. A gain control method for the initial cell searching in TD-SCDMA mobile
communication system as defined in claim 1, wherein
in Step D, said determined DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes are considered as the DwPTS positions of subframes.
6. A gain control method for the initial cell searching in TD-SCDMA mobile
communication system as defined in claim 1, wherein
in Step E, if the receiver is judged not to be in saturation and the received signal is environmental interference, there is no base station for working at present carrier frequency.
7. A gain control method for the initial cell searching in TD-SCDMA mobile
communication system as defined in claim 1, wherein
in Step E, the receiving gain is decreased by a step length ranging from 6dB to 24dB.
8. A TD-SCDMA mobile communication system having a gain controller for the initial
cell searching, said system comprising:
a receiver at the user terminal for receiving data in the maximum receiving gain at
the selected carrier frequency;
a selecting means for selecting a first carrier frequency;
a recorder for recording the received data of a plurality of subframes;
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a determining unit for determining the DwPTS position of each received subframe by using the time window decision method;
an executing means configured to perform the succeeding procedure of the initial cell searching;
a decision making unit configured to judge whether the receiver is in saturation;
a decrementing means configured to decrease the receiving gain by a step length;
a terminating means configured to end the initial cell searching;
wherein the executing means is configured to perform the succeeding procedure of the initial cell searching wherein the executing means connects to the receiver subsequently when the DwPTS positions of the most received subframes is determined, and the executing means connects to the decision maker when the DwPTS positions of the most received subframes is not determined;
wherein the decision making unit is configured to judge whether the receiver is in saturation and when the receiver is not in saturation, the decrementing means decreases the receiving gain by a step length and then the decrementing means connects to the receiver, and subsequently when the receiver is in saturation, the decrementing means connects to the recorder.
9. The TD-SCDMA mobile communication system having a gain controller for the
initial cell searching as defined in claim 8, wherein
the selecting means is configured to select a carrier frequency succeeding the previously selected carrier frequency until each possible carrier frequency is selected before the executing means or the decrementing means connects to the receiver; and a terminating means is configured to end the initial cell searching .
10. The TD-SCDMA mobile communication system having a gain controller for the
initial cell searching as defined in claim 8, wherein the determining means comprises;
a judging means configured to judge whether the DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes need to
16

be determined so that the determining means determines the DwPTS positions of the most received subframes.
11. The TD-SCDMA mobile communication system having a gain controller for the
initial cell searching as defined in claim 10, wherein;
the determining means is configured to determine continuously or at intervals, the DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes.
12. The TD-SCDMA mobile communication system having a gain controller for the
initial cell searching as defined in claim 8, wherein;
the determining means is configured to determine the DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes and then the said determined DwPTS positions whose number exceeds half of the total number of DwPTS positions in the received subframes are considered as the DwPTS positions of subframes.
13. The TD-SCDMA mobile communication system having a gain controller for the
initial cell searching as defined in claim 8, wherein the decision making unit comprises;
a judging means configured to judge whether the receiver is in saturation or not and the received signal is environmental interference, and if the receiver is judged not to be in saturation, then there is no base station for working at present carrier frequency.
14. The TD-SCDMA mobile communication system having a gain controller for the
initial cell searching as defined in claim 8, wherein;
the decrementing means is configured to decrease the receiving gain by a step length ranging from 6dB to 24dB.
15. A TD-SCDMA mobile communication system having a gain controller for the
initial cell searching, said system substantially such as herein described with reference to
and illustrated in the accompanying drawings.
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16. A gain control method for the initial cell searching in TD-SCDMA mobile communication system, said gain control method substantially such as herein described with reference to and illustrated in the accompanying drawings.
Dated this 3rd day of February, 2006
(MAHUA GHOSH)
OF K & S PARTNERS
AGENT FOR THE APPLICANTS
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ABSTRACT
'A Gain Control Method for the Initial Cell Searching in TD-SCDMA Mobile
Communication System'
The present invention discloses a gain control method used at the initial cell searching by the user terminal in TD-SCDMA mobile communication system. At each carrier frequency, the user terminal firstly receives and records the data of a plurality of subframes transmitted from a base station when the receiver is set at the maximum gain; searches the DwPTS positions by using the time window decision method; performs the succeeding steps of the initial cell searching subsequently when the DwPTS positions can be obtained; judges whether the receiver is in saturation when the DwPTS positions can not be obtained; decreases the receiver gain by a large step and receives and recordes the data of a plurality of subframes transmitted from the base station if the receiver is in saturation; and determines that there is no base station for working at the present carrier frequency if the receiver is not in saturation. The above initial cell searching procedures are repeated until the receiver is not in saturation any more. The ADC of user terminals can finish the initial cell searching under the condition of less dynamic range by using the present invention.
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Documents:

138-MUMNP-2006-ABSTRACT(5-8-2010).pdf

138-mumnp-2006-abstract(complete)-(6-2-2006).pdf

138-mumnp-2006-abstract(granted)-(12-10-2010).pdf

138-mumnp-2006-abstract.doc

138-mumnp-2006-abstract.pdf

138-mumnp-2006-cancelled pages(5-8-2010).pdf

138-MUMNP-2006-CLAIMS(AMENDED)-(5-8-2010).pdf

138-mumnp-2006-claims(complete)-(6-2-2006).pdf

138-mumnp-2006-claims(granted)-(12-10-2010).pdf

138-mumnp-2006-claims.doc

138-mumnp-2006-claims.pdf

138-mumnp-2006-correspondence(6-8-2007).pdf

138-mumnp-2006-correspondence(ipo)-(12-10-2010).pdf

138-mumnp-2006-correspondence-received-ver-020606.pdf

138-mumnp-2006-correspondence-received-ver-030206.pdf

138-mumnp-2006-correspondence-received.pdf

138-mumnp-2006-description (complete).pdf

138-mumnp-2006-description(complete)-(6-2-2006).pdf

138-mumnp-2006-description(granted)-(12-10-2010).pdf

138-MUMNP-2006-DRAWING(5-8-2010).pdf

138-mumnp-2006-drawing(complete)-(6-2-2006).pdf

138-mumnp-2006-drawing(granted)-(12-10-2010).pdf

138-mumnp-2006-drawings.pdf

138-MUMNP-2006-ENGLISH TRANSLATION(5-8-2010).pdf

138-mumnp-2006-form 1(5-5-2006).pdf

138-MUMNP-2006-FORM 1(5-8-2010).pdf

138-mumnp-2006-form 1(6-2-2006).pdf

138-mumnp-2006-form 13(5-8-2010).pdf

138-MUMNP-2006-FORM 16(24-6-2011).pdf

138-mumnp-2006-form 18(7-8-2007).pdf

138-mumnp-2006-form 2(complete)-(6-2-2006).pdf

138-mumnp-2006-form 2(granted)-(12-10-2010).pdf

138-MUMNP-2006-FORM 2(TITLE PAGE)-(5-8-2010).pdf

138-mumnp-2006-form 2(title page)-(complete)-(6-2-2006).pdf

138-mumnp-2006-form 2(title page)-(granted)-(12-10-2010).pdf

138-MUMNP-2006-FORM 26(5-8-2010).pdf

138-MUMNP-2006-FORM 3(5-8-2010).pdf

138-mumnp-2006-form 3(6-2-2006).pdf

138-MUMNP-2006-FORM 5(5-8-2010).pdf

138-mumnp-2006-form 5(6-2-2006).pdf

138-MUMNP-2006-FORM PCT-ISA-210(5-8-2010).pdf

138-mumnp-2006-form-1.pdf

138-mumnp-2006-form-2.doc

138-mumnp-2006-form-2.pdf

138-mumnp-2006-form-26.pdf

138-mumnp-2006-form-3.pdf

138-mumnp-2006-form-5.pdf

138-MUMNP-2006-OTHER DOCUMENT(5-8-2010).pdf

138-mumnp-2006-pct-search report.pdf

138-MUMNP-2006-PETITION UNDER RULE 137(1)-(5-8-2010).pdf

138-MUMNP-2006-PETITION UNDER RULE 137(5-8-2010).pdf

138-MUMNP-2006-REPLY TO EXAMINATION REPORT(5-8-2010).pdf

138-MUMNP-2006-SPECIFICATION(AMENDED)-(5-8-2010).pdf

138-MUMNP-2006-WO INTERNATIONAL PUBLICATION REPORT A1(5-8-2010).pdf


Patent Number 243391
Indian Patent Application Number 138/MUMNP/2006
PG Journal Number 43/2010
Publication Date 22-Oct-2010
Grant Date 12-Oct-2010
Date of Filing 06-Feb-2006
Name of Patentee DA TANG MOBILE COMMUNICATIONS EQUIPMENT CO., LTD.
Applicant Address A CHINESE CORPORATION OF NO. 40 XUEYUAN ROAD, HAIDIAN DISTRICT, BEIJING 100083, CHINA.
Inventors:
# Inventor's Name Inventor's Address
1 LI, Shihe Beijing 100083 (CN).
2 XU, Wensheng N0. 40 Xue Yuan Rd., Hai Dian District, Beijing 100083 (CN).
PCT International Classification Number H04Q7/00
PCT International Application Number PCT/CN2004/000878
PCT International Filing date 2004-07-28
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 03149787.X 2003-08-06 China