CN1954512A - Cell search method for radio communication system - Google Patents
Cell search method for radio communication system Download PDFInfo
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- CN1954512A CN1954512A CNA2005800082570A CN200580008257A CN1954512A CN 1954512 A CN1954512 A CN 1954512A CN A2005800082570 A CNA2005800082570 A CN A2005800082570A CN 200580008257 A CN200580008257 A CN 200580008257A CN 1954512 A CN1954512 A CN 1954512A
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Abstract
A continuous cell search method for searching a new cell in a radio communication system having a plurality of base stations and a mobile station includes: (a) a step (S1) for using a main synchronization code to establish a slot synchronization for a specified cell; (b) a step (S2) for using a sub synchronization code to detect a frame synchronization and identify a code group of the specified cell; (c) a step (S3) for deciding a main scrambling code used by the specified cell; (d) a step (S4) for terminating the post-processing of the cell corresponding to the main scrambling code specified before; (e) a step (S62) for correlating the slot timing specified in the step (a) with the frame timing corresponding to the main scrambling code specified during execution prior to the steps (b) and (c); and (f) a step (S63-S66) for terminating the processes of the steps (b) and (c) for the slot timing specified in the step (a) when a correlation is detected.
Description
Technical field
The present invention relates to have the wireless communication system of a plurality of base stations and a mobile radio station, especially, relate to the small region search method of carrying out by the mobile radio station of this system.The present invention is applicable to spread spectrum system, especially in Wideband Code Division Multiple Access (WCDMA) (the Wide band Code Division Multiple Access:W-CDMA) system.
Background technology
In other identical wireless communication system of W-CDMA, mobile radio station receives a plurality of wireless signals that send from a plurality of base stations.Under this situation, each wireless signal is by being received and dispatched in a plurality of transmission paths certain sub-district in service area.Before business datums such as transmission voice signal, implement the method for Cell searching, make the base station synchronization of this mobile radio station and sub-district by mobile radio station.
Fig. 1 is the flow chart of the small region search method of prior art.
As shown in Figure 1, existing small region search method is made of slot synchronization step S1, code group identification and frame synchronization step S2, long scrambling code identification step S3.
In slot synchronization step S1, the Primary Synchronisation Code that the mobile radio station use sends continuously by primary synchronization channel is realized the slot synchronization at the sub-district.Usually, slot synchronization is by using single matched filter or implementing with the same filter of the shared Primary Synchronisation Code in whole sub-districts coupling.The slot timing of sub-district can be determined by the peak value that detects in the matched filter output.
In the second step S2 of existing small region search method, mobile radio station uses the secondary synchronous code of synchronizing channel to detect frame synchronization, and specifies in the sub-district code group that detects among first step (slot synchronization step) S1.This step S2 is by making received signal and possible whole secondary synchronization code sequence and be associated and specifying maximum correlation value to realize.Because the cyclic shift of secondary synchronization code sequence is specific, so, not only frame synchronization can be determined, and code group can be determined.
In the third step S3 of existing small region search method, mobile radio station is determined the correct main scrambling code that uses in the sub-district of detecting.Usually, by Common Pilot Channel (Common Pilot Channel:CPICH) and the dependency relation that belongs to each code element between whole sign indicating numbers of the code group that the second step S2 determines specify main scrambling code.
In case specify out the main scrambling code that in the sub-district of detecting, uses, in step S4, the main scrambling code of specified this just and the scrambling code of front appointment tabulate and compare, thus, remove sub-district by this small region search method appointment.Then, in ensuing subsequent processes process, only handle the candidate sub-district that specified main scrambling code in tabulation 5, do not occur.
Implement continuously under the situation of Cell searching in order to specify new sub-district at mobile radio station, canonical algorithm is by the timing of the peak value that detects among the first step S1 relatively and the preceding peak value that detects when once implementing first step S1, thus, handle the peak value that detects among the first step S1.Under the situation of the timing that the old peak value that detects is very approaching, think that new peak value is the same with old peak value, does not carry out top processing when new peak value has and last time implemented Cell searching.
Whether two peak values are very approaching, are to use the parameter of automatic and adjustable to determine, this parameter-definition two peak values be regarded as maximum timing difference in the identical scope.This parameter value is caused by the error of automatic frequency control (AFC) and the drift that produces according to the maximum drift value and the timing of the mobile route compact model under and current parameter are determined.
When above-mentioned existing small region search method is carried out first step S1 in the scope of compressed mode gap, that is to say when two peak values separate mutually each other fully and usually become in paging interval work under the situation of idle pulley far away not smooth.In this case, the peak value position regularly among the first step S1 that carries out continuously is usually widely different.Therefore, can not obtain being used for determining that the definite peak value of which first step S1 belongs to the information of the sub-district of appointment before this.The worst situation continues drift because the peak value of first step S1 staggers from default window, so, with second and third step analyze the peak value of the first step S1 that belongs to same sub-district together repeatedly.In this case, after third step S3, peak value is refused repeatedly as multi-path signal, therefore, can't specify new sub-district forever.
Therefore, a kind of small region search method that can overcome of expectation with the above-mentioned shortcoming of the existing small region search method of carrying out by mobile radio station in the wireless communication system.
In addition, expect the situation that a kind of slot timing that improves in the sub-district of being detected alters a great deal, for example, separate situation under a lot of situations in the situation of operating under the W-CDMA compact model or paging interval.
Summary of the invention
The invention provides a kind of being used for is used to find out new sub-district and carries out continuous small region search method at the wireless communication system with a plurality of base stations and a mobile radio station, wherein, have following steps: (a) the use Primary Synchronisation Code is determined the step at the slot synchronization of specified sub-district; (b) use secondary synchronization code to detect frame synchronization, and, specify the step of code group of the sub-district of above-mentioned appointment; (c) determine the step of the main scrambling code that use above-mentioned specified sub-district; (d) step of the subsequent processes of the main scrambling code corresponding district of termination and previous appointment; (e) make the slot timing of appointment in above-mentioned steps (a) and corresponding to the step of formerly carrying out above-mentioned steps (b) and the frame of the main scrambling code correspondence of appointment regularly is associated (c) time; (f) when detecting dependency relation, end at the said process (b) of the slot timing of appointment in above-mentioned steps (a) and the step of processing (c).
Preferred above-mentioned steps (f) is to carry out on the slot timing of determining in above-mentioned steps (e) with strongest correlation relation.
The slot timing that has the strongest correlation relation in the preferred above-mentioned steps (e) is by the intensity of the dependency relation of each slot timing mean value divided by detected whole slot timings, and calculate the signal/noise ratio of slot timing, with above-mentioned signal/noise than and predetermined threshold value compare and draw.
Preferred above-mentioned signal/noise does not just carry out above-mentioned step (f) than surpassing predetermined threshold value.
The dependency relation of carrying out in the preferred above-mentioned steps (e) is that the several W-CDMA time slots that limited are carried out.
The dependency relation of carrying out in the preferred above-mentioned steps (e) is to carry out under the situation of identical compact model window or paging.
The present invention also provides a kind of mobile radio station that uses in having the wireless communication system of a plurality of base stations, wherein, this mobile radio station has: the slot timing detector; Frame timing and code group detector; The scrambling code detector; Correlator regularly is associated slot timing and frame, and wherein, described slot timing is by the appointment of above-mentioned slot timing detector; Regularly the above-mentioned frame when carrying out Cell searching by last time is regularly and the main scrambling code of code group detector and the appointment of above-mentioned scrambling code detector for described frame.
Preferred above-mentioned correlator has a plurality of correlators of connection arranged side by side, sets different scrambling codes in each of above-mentioned a plurality of correlators, and detect a plurality of known scrambling codes in single process.
Above-mentioned correlator has the correlator of rectangular configuration, sets the timing with the corresponding a plurality of multipath reflections of predetermined scrambling code in the correlator of each row of matrix.
By the present invention,, therefore, can improve Cell searching speed because can avoid same peak value to first step to carry out processing more than 2 times or 2 times.Why can avoid the repeatedly processing of this same peak value, be transmitting-receiving or Doppler's effect because of multi-path signal, and can determine the timing of peak.In the initial period of Cell searching, even, also can improve Cell searching speed at least from the peak value of previous sub-district refusal first step.At this moment, do not need to carry out once more the second long step of time in the Cell searching.Therefore do not need same peak value regularly.
In little compact model spaced apart, shorten the required time of intermediate frequency search at new sub-district.Therefore, can improve the performance of entire system.Also can improve the performance of the Cell searching under the idle pulley.Timing wander effect between paging is identical with the situation of compact model.
Description of drawings
The mobile radio station that Fig. 1 shows the W-CDMA form is carried out the flow chart of each step of existing small region search method.
Fig. 2 is the concise and to the point figure of W-CDMA wireless communication system.
Fig. 3 shows the block diagram of the mobile radio station of a part that constitutes W-CDMA wireless communication system shown in Figure 1.
Fig. 4 shows mobile radio station shown in Figure 3 and carries out the flow chart of each step of small region search method according to an embodiment of the invention.
Fig. 5 shows the part of small region search method shown in Figure 4, is the flow chart that shows in detail the process of removing known scrambling code.
Fig. 6 show the slot timing of appointment in the first step of the small region search method shown in Fig. 4 and in second and third step of same small region search method before the figure of the scrambling code of appointment and the frame dependency relation between regularly.
Embodiment
Fig. 2 is the concise and to the point figure as the W-CDMA wireless communication system of the objective for implementation of small region search method of present embodiment.
As Fig. 2 institute-show, wireless communication system 10 is made of W-CDMA network 12,3 base stations 14,16,18 of being connected respectively to W-CDMA network 12.
Fig. 3 shows the block diagram of the structure of mobile radio station 20.
As shown in Figure 3, mobile radio station 20 has antenna 32, the wireless signal conversion (down conversion) that will receive by antenna 32 is the demodulator 34 of base band frequency, the analog signal that receives is transformed to the A-D converter 36 of digital signal, during Cell searching, detect the slot timing detector 38 of slot timing, during Cell searching, detect the frame timing/code group detector 42 of frame timing and code group, during Cell searching, detect the scrambling code detector 44 of scrambling code, with yard second demodulator 46 that carry out demodulation of detected spreading code to being received, to the decoder 48 of decoding by second demodulator, 46 demodulated received signals, the microprocessor operating 40 of control mobile radio station 20, the program that storage microprocessor 40 is carried out, necessary memory of data 50 when storage microprocessor 40 is carried out exercises, dedicated correlator 52.
Dedicated correlator 52 detects the dependency relation of common pilot channel (CPICH) between the scrambling code and frame timing data that detect in initial peak timing data that the first step of Cell searching detects and second and the third step of sub-district at Cell searching based on previous appointment.
Below, to Fig. 6, the operation when mobile radio station 20 is implemented the Cell searching of present embodiments describes with reference to figure 4.
Fig. 4 is the flow chart that mobile radio station 20 is implemented the small region search method of first embodiment of the invention.
Carry out repeatedly under the situation of Cell searching at mobile radio station 20, carry out first step after detecting Common Pilot Channel (CPICH) dependency relation, in this first step, specified home there is no need to carry out the peak value of above-mentioned processing simultaneously in the sub-district of previous appointment.As shown in Figure 4, in order to detect the peak value among the step S1, processing sequence is step S1, remove the step S60 of known sub-district, step S2, step S3.
In removing the second step S60 of known cell, analyze N the peak value of the strongest step S1, determine whether these peak values belong in the sub-district of appointment.
Fig. 5 shows the flow chart of each step of carrying out in removing the step S60 of known scrambling code.
As shown in Figure 5, in step S60, at first, in step S62, make by the detected original slot timing of the peak value of up-to-date step S1, regularly on Common Pilot Channel (CPICH), be associated with scrambling code that detects based on known cell and frame.
Next, in step S63, use the mean value of the amplitude of the correlation of trying to achieve as mentioned above, obtain the general estimated value of signal/noise (SN ratio) ratio of Common Pilot Channel (CPICH) divided by step S1.
Then, in step S64, judge that this signal/noise is bigger than predetermined threshold value than whether.
Compare (YES among the step S64) under the big situation of threshold value at signal/noise, mean to detect known scrambling code, at this moment, the peak value in step S65 among the discarded step S1 that is provided.
Signal/noise is further handled the peak value among the step S1 that detects in step S66 than unlike under the big situation of threshold value (NO among the step S64).
Fig. 6 shows the timing in the known treatment of refusal scrambling code and the arrangement of the candidate value of scrambling code.
The purpose of Common Pilot Channel (CPICH) is that to find out in the correlation peak of step S1 which peak value corresponding with known scrambling code, and ends the various above-mentioned processing of this peak value.In Fig. 6, be shown in broken lines and the corresponding peak value of known scrambling code.
Can use in device that device, the path of using in the step S3 of Cell searching use in measuring step by step or the correlator 52 shown in Figure 3 any one to implement the dependency relation of Common Pilot Channel (CPICH).Correlator 52 can be made of a plurality of correlators of parallel connection configuration, in this case, different scrambling code mutually is set in each correlator, and each correlator detects the known scrambling code that differs from one another in single process.
Perhaps, correlator 52 can be made of the correlator of rectangular arrangement.In this case, to each known scrambling code of correlator assigns of going of matrix.To the correlator assigns of each row of matrix at the timing of the corresponding known multipath reflection of predetermined scrambling code.Therefore, correlator 52 detects known scrambling code and at the given frame timing value of each scrambling code in single process.
In order to improve the average speed of the integral body that detects the sub-district that makes new advances, the needed processing time that is associated must be short more a lot of than step S2 common in the Cell searching and step S3.Be associated can with a W-CDMA time slot, for example the code element of 10 Common Pilot Channel is equally short.Though, also enough detect the strongest sub-district at the integration time of this weak point of dependency relation of big processing gain the required processing gain in cell search procedure S3 not.The execution of this treatment step is not very important.Can not detect the sub-district even reason is this step, can not cause the failure of Cell searching, resolve, therefore the algorithm of operative norm once more because only carry out 2 minor peaks.
Early stage, just in the dependency relation of carrying out at short notice, the peak lists that energy just public compact model window of enough public pulse trains or public paging come treatment step S1, therefore, wish that the step remove the sub-district uses the up-to-date slot timing of deriving to carry out from the peak value of step S1.
Above-mentioned structure can improve the bulk velocity of Cell searching, therefore, and can be to carry out the step that is associated than step S2 and short a lot of time of step S3.After carrying out this step that is associated, remove the strongest several sub-districts, not to the sub-district of appointment but the stronger peak value that belongs to new sub-district is come execution in step S2 and step S3.
As advantage, in removing the process of known scrambling code, the process that is associated with the short time just, have with the very approaching frame known cell regularly of the peak value of the pre-arranged procedure S1 in also can implement.This can be by coming the above-mentioned rectangular correlator of prestrain to finish in the timing of deriving from step S1 (this timing and known sub-district timing are very close).Thus, can improve the bulk velocity of removing known scrambling code.Reason is that the frame of sub-district regularly need not to move significantly between continuous mensuration window, therefore, can not waste on the scrambling code that keeps clear of predetermined timing and handle resource (rectangular correlator).
By present embodiment, can improve the processing speed that improves mobile radio station by step S1 detection peak, therefore, in the given time, can analyze the peak value of step S1 as much as possible.
The information that use obtains from the sub-district of known appointment can improve the analysis speed of the peak value of step S1.
In addition, the foregoing description is not got rid of the change or the increase of said structure, and any change in purport scope of the present invention or increase all are fine.
Claims (11)
1. method of carrying out continuous Cell searching in order to find out new sub-district in the wireless communication system with a plurality of base stations and a mobile radio station wherein, has following steps:
(a) the use Primary Synchronisation Code is determined the step at the slot synchronization of specified sub-district;
(b) use secondary synchronization code to detect frame synchronization, specify the step of code group of the sub-district of above-mentioned appointment simultaneously;
(c) determine the step of the above-mentioned specified employed main scrambling code in sub-district;
(d) step of the subsequent processes of the main scrambling code corresponding district of termination and previous appointment;
(e) make the slot timing of appointment in above-mentioned steps (a) and corresponding to the step of formerly carrying out above-mentioned steps (b) and the frame of the main scrambling code of appointment regularly is associated (c) time;
(f) when detecting dependency relation, end at the said process (b) of the slot timing of appointment in above-mentioned steps (a) and the step of processing (c).
2. continuous small region search method according to claim 1, wherein, above-mentioned steps (f) is to carry out on the slot timing of determining in above-mentioned steps (e) with strongest correlation relation.
3. according to claim 1 or 2 described continuous small region search methods, wherein, the above-mentioned slot timing that has the strongest correlation relation in the above-mentioned steps (e), be by the intensity of the dependency relation of each slot timing mean value divided by the whole slot timings that detected, and calculate the signal/noise ratio of slot timing, with above-mentioned signal/noise than and predetermined threshold value compare and definite.
4. continuous small region search method according to claim 3, wherein, above-mentioned signal/noise does not just carry out above-mentioned step (f) than surpassing predetermined threshold value.
5. according to the continuous small region search method of any record among the claim 1-4, wherein, being associated of implementing in the above-mentioned steps (e) is that the several W-CDMA time slots to being limited carry out.
6. according to the continuous small region search method of any record among the claim 1-5, wherein, being associated of implementing in the above-mentioned steps (e) carried out under identical compact model window or paging situation.
7. mobile radio station that in having the wireless communication system of a plurality of base stations, uses, wherein, this mobile radio station has:
The slot timing detector;
Frame timing and code group detector;
The scrambling code detector;
Correlator regularly is associated slot timing and frame, and wherein, described slot timing is by the appointment of above-mentioned slot timing detector; Described frame regularly corresponding to when carrying out Cell searching last time by above-mentioned frame regularly and the main scrambling code of code group detector and the appointment of above-mentioned scrambling code detector.
8. mobile radio station according to claim 7, wherein, above-mentioned correlator has a plurality of correlators of connection arranged side by side, sets different scrambling codes in each of above-mentioned a plurality of correlators, detects a plurality of known scrambling codes in single process.
9. according to the mobile radio station of claim 7, wherein, above-mentioned correlator has the correlator of rectangular configuration, has set the timing with the corresponding a plurality of multipath reflections of predetermined scrambling code in the correlator of each row of matrix.
10. mobile radio station according to claim 7, wherein, above-mentioned mobile radio station can be made of mobile phone.
11. a program that makes computer built-in in the above-mentioned mobile radio station carry out continuous Cell searching in order to detect the new sub-district in the wireless communication system with a plurality of base stations and a mobile radio station, wherein, this program is used for carrying out
(a) the use Primary Synchronisation Code is determined the processing at the slot synchronization of designated cell;
(b) use secondary synchronization code to detect frame synchronization, specify the processing of the code group of above-mentioned designated cell simultaneously;
(c) determine the step of the employed main scrambling code in sub-district of above-mentioned appointment;
(d) subsequent processes of the corresponding sub-district of main scrambling code of termination and previous appointment;
(e) make the slot timing of above-mentioned steps (a) appointment and corresponding to the processing of formerly carrying out above-mentioned steps (b) and the frame of the main scrambling code of appointment regularly is associated (c) time;
(F) when detecting dependency relation, end said process (b) and processing (c) at the slot timing of appointment in the above-mentioned steps (a).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2004901383A AU2004901383A0 (en) | 2004-03-16 | Cell search process for wireless communication system | |
| AU2004901383 | 2004-03-16 | ||
| AU2005200628 | 2005-02-11 |
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| Publication Number | Publication Date |
|---|---|
| CN1954512A true CN1954512A (en) | 2007-04-25 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNA2005800082570A Pending CN1954512A (en) | 2004-03-16 | 2005-03-16 | Cell search method for radio communication system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108574548A (en) * | 2017-03-13 | 2018-09-25 | 电信科学技术研究院 | A kind of small region search method and UE |
-
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- 2005-03-16 CN CNA2005800082570A patent/CN1954512A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108574548A (en) * | 2017-03-13 | 2018-09-25 | 电信科学技术研究院 | A kind of small region search method and UE |
| CN108574548B (en) * | 2017-03-13 | 2019-09-17 | 电信科学技术研究院 | A kind of small region search method and UE |
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Application publication date: 20070425 |