CN100364254C - Frequency deviation evaluation device and method - Google Patents
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- CN100364254C CN100364254C CNB2004100780033A CN200410078003A CN100364254C CN 100364254 C CN100364254 C CN 100364254C CN B2004100780033 A CNB2004100780033 A CN B2004100780033A CN 200410078003 A CN200410078003 A CN 200410078003A CN 100364254 C CN100364254 C CN 100364254C
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Abstract
The present invention provides a frequency offset estimation device and a frequency offset estimation method. The frequency offset estimation device comprises an effective diameter selector, an effective diameter data extractor, at least one single-diameter frequency offset estimator and an effective diameter frequency offset combining calculator, wherein effective diameters of which the number is less than or equal to a preset number are selected according to a frame of data and local signals, which are received, and the position information of the effective diameters are calculated. Each synchronous code data containing the selected effective diameters is extracted respectively from the received data by the effective diameter data extractor according to the position information of a plurality of selected effective diameters, which are output by the effective diameter selector. The frequency offset estimation is independently carried out by each effectively diameter in the single-diameter frequency offset estimator according to the synchronous code data of each effective diameter extracted by the effective diameter data extractor and the local signals. When the effective diameter frequency offset combining calculator receives all estimated frequency offset of the selected effective diameters of the frame, the estimated frequency offset of each diameter is combined, and the frequency offset of the frame is calculated.
Description
Technical Field
The present invention relates to a frequency offset estimation apparatus and method, and more particularly, to a frequency offset estimation apparatus and method for use in a TD-SCDMA terminal in a mobile communication system.
Background
With the development and popularization of wireless communication businesses, the number of mobile communication users has been increasing exponentially, and particularly, mobile users in china have been increasing at a rate of 150% or more for several years. Users are also increasingly demanding on the speed and quality of communications. In a wireless communication system, when a user terminal is powered on, a large frequency deviation exists between a carrier frequency and a local crystal oscillator. Only if the frequency deviation is estimated quickly and effectively, the frequency compensation can be carried out, and the frequency deviation which can be accepted by a receiver is achieved, so that the next task flow is carried out. For example, in a TD-SCDMA system, when a user terminal is turned on, since a local oscillator and a carrier have a large initial frequency deviation, it is necessary for a receiver to estimate a frequency deviation between the carrier and a local oscillator, perform frequency compensation, and perform a next task process after the receiver meets the requirement. Therefore, how to quickly and effectively estimate the frequency deviation in a mobile communication system terminal is a key part of the mobile communication field that is suitable for the communication speed and quality.
The conventional frequency offset estimation generally adopts a multiple signal classification (MUSIC) method, a rotation invariant technique Estimation Signal Parameter (ESPRIT) method, a Least Square Channel Estimation (LSCE) method, and the like. These methods result in matrix operations and large computational complexity.
Disclosure of Invention
In order to overcome the above disadvantages, the present invention provides a simple and effective apparatus and method for estimating the frequency deviation between the carrier frequency and the local crystal oscillator.
The frequency offset estimation device of the present invention comprises: an effective path component detection device, which selects effective paths less than or equal to a preset number according to a received frame data and local signals, and calculates the position information of the effective paths; an effective diameter data extractor for extracting synchronous code data each including a selected effective diameter from the received data, respectively, in accordance with position information of a plurality of selected effective diameters outputted from the effective diameter component detecting means; at least one single-path frequency offset estimator, which performs frequency offset estimation independently according to each effective path according to the synchronous code data and the local signal of each effective path extracted by the effective path data extractor; an effective path frequency offset combiner for combining the estimated frequency offsets of each path when receiving the estimated frequency offsets of all the selected effective paths of the frame; and the frequency offset calculator calculates the frequency offset of the frame according to the combined result of the estimated frequency offsets of all the paths.
The frequency offset estimation method of the invention comprises the following steps: selecting effective paths smaller than or equal to a preset number by using an effective path component detection device according to received frame data and local signals, and calculating position information of the effective paths; extracting synchronous code data including each selected effective diameter according to the position information of the selected effective diameter by using an effective diameter data extractor; independently estimating each selected synchronous code data by utilizing at least one single-path frequency offset estimator to obtain the estimated frequency offset of each effective path; combining the estimated frequency offsets of all the selected effective paths by using an effective path frequency offset combiner; and calculating the frequency offset of the frame by using a frequency offset calculator according to the combined result of the estimated frequency offsets of all the selected effective diameters.
The invention calculates the frequency offset of the current frame by carrying out single-path frequency offset estimation on each path in communication and combining all the single-path estimated frequency offsets, thereby avoiding directly carrying out frequency offset estimation on multiple paths and further reducing the complexity of frequency offset estimation.
Drawings
FIG. 1 is a schematic diagram of a subframe structure of TD-SCDMA;
FIG. 2 is a schematic diagram of the structure of DwPTS;
FIG. 3 is a diagram illustrating a frequency offset estimation apparatus according to a first embodiment of the present invention;
FIG. 4 is a diagram illustrating data extracted by the SYNC-DL segment data extractor;
FIG. 5 is another schematic diagram of data extracted by the SYNC-DL segment data extractor;
FIG. 6 is a schematic diagram of a first configuration of an effective path component selector;
FIG. 7 is a schematic diagram of a second configuration of an effective path component selector;
FIG. 8 is a schematic diagram of a fourth configuration of an effective path component selector;
FIG. 9 is a diagram illustrating data extracted by the effective diameter data extractor;
fig. 10 is a schematic diagram of a single-path frequency offset estimator;
fig. 11 is another structural diagram of a single-path frequency offset estimator;
fig. 12 is a diagram illustrating a frequency offset estimation apparatus according to a second embodiment of the present invention.
Detailed Description
The present invention will be described in detail below with reference to an example of its application in a time division synchronous code division multiple access (TD-SCDMA) terminal User (UE).
In order to more clearly illustrate the data transmission and reception process in the TD-SCDMA system, first, referring to fig. 1-2, a subframe structure of TD-SCDMA is described. As shown in fig. 1, TD-SCDMA is a time unit with 5ms as one subframe. Each TD-SCDMA sub-frame is divided into 7 common time slots (TS 0-TS 6) and three special time slots: one downlink pilot time slot (DwPTS), one uplink pilot time slot (UpPTS), and one Guard Period (GP). Each 5ms subframe consists of 6400 chips. The normal Time Slot (TS) in each subframe comprises two data blocks of 352 chips each, a Midamble code (training sequence) code block of 144 chips and a guard time slot of 16 chips. As shown in fig. 2, the structure diagram of DwPTS is composed of a downlink synchronization code (SYNC-DL) with a length of 64 chips and a Guard Period (GP) with a length of 32 chips, where SYCN-DL is a set of pseudo random codes (PN) assigned to different cells for cell search and downlink synchronization. The received SYNC-DL chips contain frequency offset information under the multipath channel.
The inventive concept of the present invention is first described. Assuming that the user can receive signals from B base stations, the SYNC-DL part of the data received by the user will contain the accumulation of B mutually different SYNC-DL codes. The SYNC-DL signal transmitted from base station b can be represented as s b [k]And k is greater than or equal to 0 and less than 64, wherein k is the index of SYNC-DL discrete chips. Receiving the multipath number of the signal transmitted by the base station b by N b Is expressed and the number of chips of each multipath delay is usedThen the corresponding channel coefficient of base station b can be expressed as:
the total power of b of the received base station is expressed as
Here, let P be 1 ≥P b And 2 ≦ B, the base station 1 is generally the "desired" base station, the others are interfering base stations, and the instantaneous power of the base station that may also interfere exceeds that of the "desired" base station.
Assuming a frequency offset of the carrier, v, the user received signal is represented in time spaced chips, which may be written as,
here, n [ k ] is additive noise, including adjacent channel interference and white Gaussian noise.
Ignoring all interference, including interference from other base stations, adjacent channel interference and white gaussian noise, only considering the "desired" base station, the user received signal can be expressed as,
if only a single effective path is considered each time a frequency offset estimation is performed, the other paths are considered to be interference present, which can be expressed as follows,
r[k]＝exp(j2πv T c k) h b [κ b，n ] s b [k-κ b，n ]+i[k]+n[k](ii) a k =0,1, \8230;, 63 (3) where n ∈ [0,n b ]Is one of the effective diameters.
< first embodiment of the invention >
Referring to fig. 3, the frequency offset estimation apparatus 10 according to the first embodiment of the present invention includes a SYNC-DL segment data extractor 1, a local reference signal generator 5, an effective path component detection apparatus 3, and a frequency offset estimator 4. The frequency offset estimator 4 includes an effective path data extractor 41, a plurality of single path frequency offset estimators 42, an effective path frequency offset combiner 43 and a frequency offset calculator 44. In addition, an auxiliary device frame sync detector 2 is briefly described for clarity of the inventive apparatus 10.
When the UE is powered on, first to determine the location of the cell where the UE is located, the frame synchronization detector 2 searches for the location of the frame synchronization through one or more matched filters (or correlators), and the location of the SYNC-DL is known according to the frame structure shown (see fig. 1). The data extractor extracts the data with the corresponding position length of L chips according to the SYNC-DL position information which is detected by the frame synchronization detector 2, and the data range required to be extracted in the extraction process definitely comprises all multipath information of the SYNC-DL section data of 64 chips. As shown in fig. 4 and 5, the frame synchronization detector 2 can output the frame synchronization position in two different ways, that is, in synchronization with the first effective path and in synchronization with the maximum effective path, thereby bringing about two data extraction ways of the SYNC-DL segment data extractor 1. In the extraction method shown in fig. 4, assuming that the frame synchronization is a position where the first effective path is synchronized, the SYNC-DL segment data extractor 1 extracts data having a length of L = (64 + Δ k +2 × Δ E) chips, where Δ k is the number of chips having the maximum delay of the effective path compared to the first effective path and Δ E chips are for compensating for the influence of the synchronization accuracy error. In the extraction method shown in fig. 5, assuming that the frame synchronization is a position where the main path is synchronized, the SYNC-DL-segment data extractor 1 extracts data having a length of L = (64 +2 × Δ k +2 × Δ E) chips, where Δ k is the number of chips having the maximum delay from the maximum effective path and Δ E chips are for compensating for the influence of the synchronization accuracy error. In TD-SCDMA systems, Δ k is equal to 15 chips at minimum. Δ E may be set according to the frame synchronization error accuracy. The data extracted by the SYNC-DL segment data extractor 1 are input to the effective path component detection means 3 and the frequency offset estimator 4, respectively.
The effective path component detecting apparatus 3 includes a correlator 31, a correlation power calculator 32, a maximum detector 33, and an effective path component selector 34. Which are described separately below.
The data extracted by the SYNC-DL segment data extractor 1 is input to the correlator 31. In addition, the reference signal generator 5 generates the corresponding locally referenced SYNC-DL data, i.e. the local signal, from the sequence number of the SYNC-DL code that the receiver needs to search for, which local signal is also input to the correlator 31. Correlator 31 performs correlation operation on the local signal input by reference signal generator 5 and the received data extracted by data extractor 1, and outputs a complex correlation result with length L-64+ 1. The correlator 31 may also be replaced by a matched filter.
The complex correlation result output from the correlator 31 is input to the power calculator 32, and the power calculator 32 performs a modulo-square (or modulo) -operation on the input data to obtain a correlation power value, the magnitude of which can reflect the strength of each path. The results output from the correlation power calculator 32 are input to the maximum value detector 33 and the effective path component selector 34, respectively.
The maximum detector 33 detects the maximum power value, the second maximum power value, until the nth maximum power value in turn from the correlation power result, and records the power values and corresponding position values thereof, respectively. The value of N here is variable, and generally may be set to 4 to 6, and the result of the maximum detector 33 is output to the effective path component selector 34.
The inputs to the effective path component selector 34 are the result of the maximum detector 33 (the N maximum power values and corresponding position values) and the correlation power value output by the correlation power calculator 32. The effective path component selector 34 selects the number of effective paths 
Is the actual effective diameter N b And outputs position information and power information of the selected respective effective paths. The output position information of each effective path is used to control the extraction of data of each effective path information, and the output power information of each effective path is used to control the combination of frequency offsets of each effective path, which will be described in detail later. The effective path component selector 34 has four different configurations and methods for selecting
An effective diameter.
As shown in fig. 6, the first structure of the effective-path-component selector 34 is: which includes a noise power calculator 341 and a noise threshold determiner 342. The noise power calculator 341 calculates the noise power based on the values of all the correlation powers inputted from the correlation power calculator 32 and the N correlation powers inputted from the maximum detector 33The maximum power value calculates the corresponding noise power. The specific noise power is calculated firstlyFilters the correlation power value outputted from the maximum detector 33, and then averages the remaining correlation power values, i.e. the noise power value P noise . The noise threshold decision unit 342 may select the noise power value from the noise power calculator 341 and the N maximum power values detected by the maximum value detector 33And recording position information and power information of each selected effective path. The specific decision formula is as follows:
|P i -P noise |＞T 1 ；i＝1，2，3，...，N (4)
where P is i Is the ith power value, P noise Noise power value, T 1 Is a first threshold value. If the N maximum power values detected by the maximum value detector 33 satisfy the signal-to-noise ratio threshold condition in the above formula (4), the N maximum power values are determined as the effective path components and the corresponding positions and powers are recorded. At this time, the process of the present invention,
as shown in fig. 7, the second structure of the effective-path-component selector 34 is: which includes a maximum path threshold decision device 343. The maximum path threshold decision unit 343 compares the maximum effective path among the effective paths with all the effective paths, and selects the effective path if the difference between the two effective paths is smaller than a predetermined threshold value. The decision formula is as follows:
|P max -P i |＜T 2 ；i＝1，2，3，...，N (5)
where P is i Is the ith power value, P max Is the maximum value (i.e. the power value of the main path) of the N powers output by the maximum value detector 33, T 2 Is the second threshold value. The maximum path threshold decision device 343 determines that the absolute difference is less than the threshold condition of formula (5) according to the comparison between the N maximum power values detected by the maximum detector 33 and the power values of the main pathBreaking into effective path components and recording their corresponding positions. At this time, the process of the present invention,
the third structure of the effective path component selector 34 is: the device comprises a noise power calculator, a noise threshold decision device and a maximum path threshold decision device which are mentioned in the two structures. The noise power calculator and the noise threshold decision device are the same as those of the first effective path component selector, and the maximum path threshold decision device is the same as that of the second effective path component selector. When the effective path component selector with the structure is adopted, the effective path component can be judged and the corresponding position can be recorded only by simultaneously meeting the conditions of the two threshold judgers. The performance of the effective path component selector is better than that of the first two effective path component selectors.
As shown in fig. 8, the fourth structure of the effective-path-component selector 34 is: the selected N maximum values are directly output as effective path components without any judgment and operation. This configuration is the simplest and coarse component of the selected effective path.
The frequency offset estimation apparatus 4 includes an effective path data extractor 41, a plurality of single path frequency offset estimators 42, a frequency offset combiner 43 and a frequency offset calculator 44. The results obtained by the single-path frequency offset estimator 42 and the frequency offset combiner 43 are complex digital diggings containing frequency offset information.
The effective path data extractor 41 receives the data from the SYNC-DL segment data extractor 1 and the position information of the effective path from the effective path component selector 44, and extracts the SYNC-DL data of each effective path from the data output from the SYNC-DL segment data extractor 1 based on the position information of each effective path, respectively (as shown in fig. 9). The method for extracting the SYNC-DL data containing the corresponding effective path is shown in fig. 9. That is, starting with the position of the effective path, 64 data are extracted consecutively. Extracted by the effective path data extractor 41
The SYNC-DL data of each effective path is input into one single-path frequency offset estimator 42, i.e. the SYNC-DL data of each effective path is input into only one single-path frequency offset estimator 42. Meanwhile, the local reference signal from the local reference signal generator 5 is also input to each single-path frequency offset estimator 42.
Each single-path frequency offset estimator 42 performs frequency offset estimation on a single effective-path signal using SYNC-DL data output from the effective-path data extractor 41 and the local reference signal transmitted from the local reference signal generator 5. Each single path frequency offset estimator 42 only considers a single effective path input to the single path frequency offset estimator 42 when performing frequency offset estimation, and other effective paths are considered to exist as interference and can be expressed by the following formula (i.e. the above-mentioned formula (3)),
r[k]＝exp(j2πv T c k)h b [κ b，n ]s b [k-κ b，n ]+i[k]+n[k](ii) a k =0, 1.., 63 here,is one of the effective diameters of the two-dimensional,
is the actual effective diameter N b An estimate of (d).
Fig. 10 and fig. 11 show two specific configurations of the single-path frequency offset estimator 42, respectively. The single path frequency offset estimator 42 shown in fig. 10 includes two data equalizers 421, m correlators 422, m-1 conjugate point multipliers 423, and an accumulator 424. The two data equalizers 421 divide the input data of path n and the local signal into m equal parts with the same length, and prepare for the following estimation, where m is variable and is at least 2, i.e., m ≧ 2.m can be selected according to the length of the training sequence, but m is not too large for short training sequences. The data of the corresponding divided path n and the local signal are input to the same correlator 422, and the output data of two adjacent correlators 422 are input to a conjugate point multiplier 423. The accumulator adds all the conjugate point multiplier 423 outputs.
The single path frequency offset estimator 42 of fig. 11 is substantially the same as the single path frequency offset estimator 42 of fig. 10, and includes two data equalizers 421, m conjugate point multipliers 423, m-1 correlators 422, and an accumulator 424. The operations performed by the data averager 421 and the accumulator 424 in the single-path frequency offset estimator 42 shown in fig. 10 and 11 are identical. The difference between the two lies in the order of implementation of the correlator 422 and the conjugate point multiplier 423. In addition, the complexity of the realization of the two is equivalent, and the performances are basically consistent.
The frequency offset estimation formulas (6) and (7) are given below by taking the double averaging (m = 2) of the data averager 421 in the single-path frequency offset estimator 42 as an example:
or
Equations (6) and (7) correspond to the structures shown in fig. 10 and 11, respectively.
The effective path frequency offset combiner 43 receives the estimated frequency offsets from all the single path frequency offset estimators 42, and combines the estimated frequency offsets to obtain a final frequency offset estimation result, where the final result is a complex value. The combining manner of the effective path frequency offset combiner 43 may be equal gain combining, maximum ratio combining, etc. The equal gain combination is to perform equal power combination, that is, direct addition, on the estimated frequency offsets of all effective paths. The result obtained is
The maximum ratio combination is carried out by utilizing the proportion of each effective path power value in the total power. In this case, in addition to the estimated frequency offsets from the respective effective paths, power information of the respective effective paths output by the effective path component selector 34 is required. The result obtained was
Wherein C n Estimating the frequency offset, P, for the effective path n n ＝|h b [κ b，n ]| 2 (i.e. power of effective path n) and(i.e., effective diameter)
Total power) of the network, here the effective path power information P n And P b The effective path power information from the output of the effective path component selector 34.
Because the data processed by the single-path frequency offset estimator 42 and the effective-path frequency offset combiner 43 are complex data containing frequency offset information, the frequency offset calculator 44 receives the complex data output by the effective-path frequency offset combiner 43 and calculates frequency offset information therein, and the frequency offset calculation formula is:
where C is the output data of the effective path frequency offset combiner 43, and T c Is the chip time, and K is the length (chip distance number) of each piece of data in data averager 421 in single-path frequency offset estimator 42.
< operation of the first embodiment of the present invention >
First, a SYNC-DL segment data extractor 1 extracts data of length L, which includes all multipath information, from received communication data.
The effective path component detecting means 3 selects data extracted by the SYNC-DL stage data extractor 1
Control information of an effective path, the control information including
Location information and power information for each of the active paths.
Each effective diameter data is extracted by an effective diameter data extractor 41 based on the position information in the effective diameter control information acquired by the effective diameter component detection device 3.
Each effective path is estimated by a plurality of single-path frequency offset estimators 42, and then the frequency offsets estimated by the plurality of single-path frequency offset estimators 42 are combined by an effective path frequency offset combiner 43 to obtain complex data of the frame estimated frequency offset, and then a frequency offset calculator 44 is used to calculate real frequency offset data.
< construction and operation according to the second embodiment of the present invention >
The frequency offset estimation apparatus 10' according to the second embodiment of the present invention is substantially the same as the frequency offset estimation apparatus 10 according to the first embodiment of the present invention. In addition, the operation of both is also substantially the same. Hereinafter, the difference between the two will be described with emphasis, and the same will not be described repeatedly.
The frequency offset estimator 4 'of the frequency offset estimation apparatus 10' according to the second embodiment of the present invention includes only one single-path frequency offset estimator 42, which performs frequency offset estimation according to each effective path in turn and inputs the estimated frequency offset of the effective paths to the effective path frequency offset combiner 43. When the effective path frequency offset combiner 43 receives the estimated frequency offsets of all the selected effective paths of the frame, it combines the estimated frequency offsets of the effective paths, and inputs the combined result to the frequency offset calculator 44, thereby calculating a frequency offset value.
Claims (21)
1. A frequency offset estimation apparatus, comprising:
an effective path component detection device, which selects an effective path less than or equal to a preset number according to a received frame data and a local signal, and calculates the position information of the effective paths;
an effective diameter data extractor for extracting each sync code data including the selected effective diameter from the received data according to the position information of the effective diameters outputted from the effective diameter component detecting means;
at least one single-path frequency offset estimator, which performs frequency offset estimation independently according to each effective path according to the synchronous code data and the local signal of each effective path extracted by the effective path data extractor;
an effective diameter frequency deviation combiner, which combines the estimated frequency deviations of all the paths after receiving the estimated frequency deviations of all the selected effective diameters of the frame; and
and a frequency offset calculator for calculating the frequency offset of the frame according to the combined result of the estimated frequency offsets of all the paths.
2. The frequency offset estimation apparatus of claim 1, comprising a plurality of single-path frequency offset estimators, the number of single-path frequency offset estimators corresponding to the number of effective paths selected, and each single-path frequency offset estimator estimating a frequency offset according to the corresponding effective path.
3. The frequency offset estimating apparatus according to claim 1 or 2, further comprising a synchronization data extractor for extracting synchronization data from a frame of data, the synchronization data including synchronization information of all effective paths in the frame, and the extracted data being inputted to the effective path component detecting means and the effective path data extractor, respectively.
4. The frequency offset estimating apparatus in claim 3 wherein the sync data extractor extracts data of length L = (64 + Δ k +2 × Δ E) chips with the first effective path as the sync position, where Δ k is the number of chips of the maximum delay of the effective path compared to the first effective path and Δ E is the number of chips for compensating the sync precision error.
5. The frequency offset estimating apparatus of claim 3 wherein the synchronous data extractor extracts data of length L = (64 +2 Δ k +2 Δ E) chips with the maximum effective diameter as the synchronous position, where Δ k is the number of chips of the maximum delay compared to the maximum effective diameter and Δ E is the number of chips compensating for the synchronous accuracy error.
6. The frequency offset estimation apparatus of claim 1 or 2 wherein the single path frequency offset estimator comprises:
the two data equipartition devices are used for respectively equipartiting the received synchronous code data and the received local signal into m equal parts;
m conjugate point multipliers, each of which receives an equal part of the sync code data and the local signal;
m-1 correlators, each correlator receiving data from outputs of two adjacent conjugate point multipliers; and
an accumulator for accumulating the data output by all correlators and outputting the accumulated data.
7. The frequency deviation estimating apparatus according to claim 1 or 2, wherein the single-path frequency deviation estimator comprises:
the two data equipartition devices are used for respectively equipartiting the received synchronous code data and the received local signal into m equal parts;
m correlators, each correlator receiving an aliquot of sync code data and a local signal;
m-1 conjugate point multipliers, each conjugate point multiplier receiving data from two adjacent correlators; and
and the accumulator accumulates and outputs the data output by all the conjugate point multipliers.
8. The frequency deviation estimating apparatus of claim 1, wherein the effective path frequency deviation combiner uses equal gain combination to directly add the estimated frequency deviations of all selected effective paths output by the single path frequency deviation estimator.
9. The frequency offset estimation apparatus of claim 1 wherein the effective path component detection means further calculates power information of the selected effective path, and the effective path frequency offset combiner combines the estimated frequency offsets of each effective path according to the respective power information by using maximum ratio combining according to the power information outputted from the effective path component detection means.
10. The frequency deviation estimating apparatus as claimed in claim 1 or 2, wherein the effective path component detecting means comprises:
a correlator for performing correlation operation on the data extracted by the synchronous data extractor and the local signal;
a correlation power calculator for calculating the power of all effective diameters according to the correlation result output by the correlator;
a maximum detector for detecting N maximum power paths according to all the relevant power values output by the relevant power calculator; and
an effective path componentA selector for selecting effective paths from the N paths with maximum power according to the output of the correlation power calculator and the maximum detector, and recording the number of the selected effective paths as
11. The frequency deviation estimating apparatus of claim 10 wherein the effective path component selector comprises:
a noise power calculator for calculating noise power based on the outputs of the correlation power calculator and the maximum detector; and
a noise threshold decision device for comparing all the outputs of the detector with the noise power calculated by the noise power calculator and selecting one according to the comparison result of the noise threshold decision device
The effective diameter of the active diameter is smaller than the effective diameter,
12. the frequency offset estimation apparatus of claim 10 wherein the effective path component selector comprises a maximum path threshold determiner for comparing all outputs of the most significant detector with a maximum output of the most significant detector, and wherein the selection is made in accordance with a result of the comparison by the maximum path threshold determiner
The effective diameter of the active pipe is as follows,
13. the frequency deviation estimating apparatus of claim 10 wherein the effective path component selector comprises:
a noise power calculator for calculating noise power based on the outputs of the correlation power calculator and the maximum detector;
a noise threshold decision device for comparing all the outputs of the maximum detector with the noise power calculated by the noise power calculator, and
a maximum path threshold decision device which compares all the outputs of the maximum detector with the maximum output of the maximum detector,
according to the comparison result of the noise threshold decision device and the maximum path threshold decision device, selecting
The effective diameter of the active diameter is smaller than the effective diameter,
14. the frequency offset estimation apparatus of claim 10 wherein the effective path component selector selects the N effective paths detected by the most significant detector as the most significant paths
An effective diameter.
15. A method of frequency offset estimation, comprising the steps of:
selecting a predetermined number of effective paths according to received frame data and local signals by using an effective path component detection device, and calculating position information of the effective paths;
extracting the synchronous code data containing each selected effective diameter according to the position information of the selected effective diameter by an effective diameter data extractor;
independently estimating the synchronous code data of each selected effective diameter by utilizing at least one single-diameter frequency offset estimator to obtain the estimation frequency offset according to each effective diameter;
using an effective diameter frequency offset combiner to combine the estimated frequency offsets of all the selected effective diameters; and
and calculating the frequency offset of the frame by using a frequency offset calculator according to the combined result of the estimated frequency offsets of all the selected effective paths.
16. The frequency offset estimation method of claim 15, characterized in that:
and estimating the frequency offset according to each effective path by utilizing a plurality of single-path frequency offset estimators.
17. The method of frequency offset estimation according to claim 15 or 16, further comprising the steps of: before selecting the effective path and extracting the sync code data, sync data including data information of the sync codes of all the effective paths in one frame is extracted from one frame by a sync data extractor.
18. The frequency offset estimation method of claim 17 wherein: the synchronous data extraction is data which takes the first effective path as a synchronous position and extracts the length of L = (64 + delta k +2 × delta E), wherein delta k is the number of chips of the maximum time delay of the effective path compared with the first effective path, and delta E is the number of chips for compensating the synchronous precision error.
19. The frequency offset estimation method of claim 17, characterized in that: the synchronous data extraction is data with the maximum effective diameter as the synchronous position and the length of L = (64 +2 Δ k +2 Δ E) chips, wherein Δ k is the number of chips with the maximum time delay of the effective diameter compared with the maximum effective diameter, and Δ E is the number of chips for compensating the synchronous precision error.
20. The frequency offset estimation method of claim 15 or 16, characterized by: the frequency deviation combining step is equal gain combining, and the estimated frequency deviations of all the selected effective paths are directly added.
21. The frequency offset estimation method of claim 15 or 16, characterized by: the frequency deviation merging step is maximum ratio merging, the power information of the selected effective diameter is calculated by using an effective diameter component detection device, and the estimated frequency deviation of all the selected effective diameters is merged according to the power information.
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| CN100459764C (en) * | 2006-08-08 | 2009-02-04 | 北京天碁科技有限公司 | Method and system for estimating and regulating mobile terminal frequency deviation |
| CN101026408B (en) * | 2007-01-19 | 2011-10-05 | 重庆重邮信科通信技术有限公司 | Frequency fine correction method and device for time division-synchronous CDMA system |
| CN101222473B (en) * | 2008-02-01 | 2011-04-20 | 北京天碁科技有限公司 | Frequency deviation estimation method and device |
| CN101771434A (en) * | 2008-12-26 | 2010-07-07 | 中兴通讯股份有限公司 | Method for adjusting frequency deviation of mobile terminal and device thereof |
| CN101478329B (en) * | 2009-02-03 | 2013-06-05 | 华为技术有限公司 | Method, apparatus and system for selecting path |
| CN102082753A (en) * | 2009-12-01 | 2011-06-01 | 北京泰美世纪科技有限公司 | Detection method and device of transmitter identification sequence |
| CN102136850B (en) | 2010-01-27 | 2014-04-30 | 中兴通讯股份有限公司 | Method and device for realizing automatic frequency control |
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| WO2004062222A1 (en) * | 2002-12-31 | 2004-07-22 | Nokia Corporation | Apparatus, and associated method, for estimating frequency offset of a data symbol communicated in a communication system |
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| US6445751B1 (en) * | 1999-01-29 | 2002-09-03 | Lucent Technologies Inc. | Estimation of frequency offset in a communication system |
| CN1342004A (en) * | 2000-09-05 | 2002-03-27 | 华为技术有限公司 | Frequency deviation estimation method applicable to code division multiple address access system |
| US20040087313A1 (en) * | 2002-09-19 | 2004-05-06 | Anthony Reid | Apparatus, and associated method, for estimating frequency offset using filtered, down-sampled likelihood polynomials |
| WO2004062222A1 (en) * | 2002-12-31 | 2004-07-22 | Nokia Corporation | Apparatus, and associated method, for estimating frequency offset of a data symbol communicated in a communication system |
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