CN103517289A - Method and device for determining channel impulse response of window in same-frequency multiple cells of TD-SCDMA system - Google Patents
Method and device for determining channel impulse response of window in same-frequency multiple cells of TD-SCDMA system Download PDFInfo
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Abstract
The present invention discloses a method and a device for determining channel impulse response of window in same-frequency multiple cells of a TD-SCDMA system, wherein the method comprises the following steps: acquiring channel impulse response of each same-frequency cell; intercepting the local sequence of each window; performing sliding correlation with a received signal; searching a tap which has a same relative position relationship with a respective reference point of a corresponding window in the channel impulse response of the corresponding cell according to the relative position relationship between a maximal correlative value position that corresponds with each window and a training sequence of the received signal; if the searched-out tap is effective, determining an effective bit of the channel impulse response of the corresponding window in the channel impulse response of the cell with each window, setting the effective tap of other window in the effective bit of the channel impulse response of the corresponding window to zero, and obtaining the channel impulse response of the corresponding window. The method or device according to the embodiment of the invention can accurately determine the channel impulse response of the window on condition that window exceeding occurs.
Description
Technical field
The present invention relates to mobile communication system detection technique field, particularly relate to the method and apparatus of determining window channel impulse response in a kind of TD-SCDMA system same frequency multi-cell.
Background technology
For TD-SCDMA system, according in 3GPP standard for the definition of training sequence, between different districts, adopt different training sequences, between the multi-user of same community, adopt the different cyclic shifts of same basic sequence.Receiver is implemented common frequency multi-cell channel estimation method, can obtain the channel impulse response of a plurality of communities, and the different windows of each cell channel impulse response represents the different user in community.
Channel estimating comprises initial channel estimation, channel estimating reprocessing two parts.Initial channel estimation obtains the channel impulse response initial value of a plurality of communities, first carries out subsequently noise reduction process, then channel impulse response is assigned to each window.If it is synchronous that the subscriber signal between each community within He Ge community keeps, the channel impulse response that each window is corresponding so only there will be in this window, channel impulse response after noise reduction directly can be decomposed into the window that K length is W in this case, the maximum user number that K is configured for each community, W is the length of window corresponding to each user, if each subscriber signal asynchronous meeting time of advent causes that window channel impulse response falls into other windows.Above behavior example, by descending time adjustment message of carrying, base station receives from up each user of this community synchronous the time of advent, channel impulse response exit window can not occur.But base station is asynchronous in conjunction with receiving from the time of advent between up each user of adjacent cell, certain user's channel impulse response may shift to an earlier date or lag behind and falls into other users' channel estimation window.Exit window can cause current window signal None-identified, and causes interference for previous window or a rear window.
Prior art for the consideration of exit window conventionally based on two kinds of situations:
The first, due to this community can not occur exit window situation only co-frequency neighbor cell receive signal exist exit window may, and this community is lower relatively to think adjacent cell signal power, therefore exit window situation is not considered.Do not utilize the structured message of co-frequency cell, only for this community, carry out channel estimating, with shortcut calculation, realize.This method implementation complexity is low, but is not suitable for the stronger scene of actual adjacent cell signal.
The second, by some physical layer procedure or some measured value, to suppose to have obtained co-frequency neighbor cell channel and arrive time delay value, unification is done time delay adjustment to adjacent cell channel impulse response initial results.The time delay relation of this method between only can distinguishing cell, does not distinguish the time asynchronism between user, is therefore only applicable to descendingly, and is not suitable for up.And the prerequisite of the method is the time that can know that adjacent cell channel reaches.
Summary of the invention
The present invention proposes to determine in a kind of TD-SCDMA system same frequency multi-cell the method and apparatus of window channel impulse response, even also can determine accurately the channel impulse response of window in the situation that there is exit window.
Technical scheme disclosed by the invention is as follows:
In TD-SCDMA system same frequency multi-cell, determine a method for window channel impulse response, comprising:
Obtain the channel impulse response of each co-frequency cell;
The local sequence of each window in described each co-frequency cell of intercepting, to receive signal do slide relevant, maximum related value position corresponding to each window described in determining;
According to the state of the maximum related value location positioning respective window of described each window;
According to the relative position relation of the training sequence reference point of maximum related value position corresponding to described each window and described reception signal, in the channel impulse response of described each community, window place, the tap of searching each window;
Whether the ratio of the average power of the whole channel impulse responses of power and current area of the tap of described each window of judgement is greater than predetermined threshold value, if, effective tap that the tap of determining corresponding window is respective window, the position of effective tap of described each window of record;
In the channel impulse response of each community, window place, determine that each has the channel impulse response of the window of effective tap: from thering is the position of effective tap of window of effective tap, intercept the chip of the long length of window of this community, window place as the significance bit of the channel impulse response of this window, and by effective tap zero setting of other windows in the significance bit of the channel impulse response of this window.
Preferably, described in described basis, the state of the maximum related value location positioning respective window of each window is specially:
If the maximum related value position of described window before described training sequence reference point, determines that the state of corresponding window is front exit window; If the state that corresponding window in described training sequence reference point or after described training sequence reference point in the long scope of window, is determined in the maximum related value position of described window is exit window not; If outside the scope of the maximum related value position of described window window length after described training sequence reference point, determine that the state of corresponding window is rear exit window.
Preferably, the Cyclic Prefix part that the local sequence of each window in described each co-frequency cell comprises the training sequence that respective window adopts, and length is front several chips of the local sequence that adopts of respective window.
Preferably, described to receive signal and do to slide and be relevantly:
To be separated by forward the chip of a threshold length as sliding window starting point with described training sequence reference point, will be separated by backward the chip of the long length with described threshold value sum of the window of a described window as sliding window terminating point with described training sequence reference point,
Utilize described local sequence docking to collect mail number from described sliding window starting point, receiving the length that slides backward a chip on signal at every turn, until slide into described sliding window terminating point, every slip is once done related operation one time with receiving signal, obtains corresponding correlation.
In TD-SCDMA system same frequency multi-cell, determine a device for window channel impulse response, comprise channel estimating unit, slip correlation unit, Window state determining unit, window tap determining unit, judging unit and channel impulse response determining unit,
Described channel estimating unit, for, the channel impulse response of each co-frequency cell obtained;
Described slip correlation unit, for, the local sequence of each window in described each co-frequency cell of intercepting, to receive signal do slide relevant, maximum related value position corresponding to each window described in determining;
Described Window state determining unit, for, according to the state of the maximum related value location positioning respective window of described each window;
Described window tap determining unit, be used for, according to the relative position relation of the training sequence reference point of maximum related value position corresponding to described each window and described reception signal, in the channel impulse response of described each community, window place, the tap of searching each window;
Described judging unit, be used for, whether the ratio of the average power of the whole channel impulse responses of power and current area of the tap of described each window of judgement is greater than predetermined threshold value, if, effective tap that the tap of determining corresponding window is respective window, the position of effective tap of described each window of record;
Described channel impulse response determining unit, be used for, in the channel impulse response of each community, window place, determine that each has the channel impulse response of the window of effective tap: from thering is the position of effective tap of window of effective tap, intercept the chip of the long length of window of this community, window place as the significance bit of the channel impulse response of this window, and by effective tap zero setting of other windows in the significance bit of the channel impulse response of this window.
Preferably, described Window state determining unit specifically for:
If the maximum related value position of described window before described training sequence reference point, determines that the state of corresponding window is front exit window; If the state that corresponding window in described training sequence reference point or after described training sequence reference point in the long scope of window, is determined in the maximum related value position of described window is exit window not; If outside the scope of the maximum related value position of described window window length after described training sequence reference point, determine that the state of corresponding window is rear exit window.
Preferably, the Cyclic Prefix part that the local sequence of each window in described each co-frequency cell comprises the training sequence that respective window adopts, and length is front several chips of the local sequence that adopts of respective window.
To be separated by forward the chip of a threshold length as sliding window starting point with described training sequence reference point, will be separated by backward the chip of the long length with described threshold value sum of the window of a described window as sliding window terminating point with described training sequence reference point,
Preferably, described slip correlation unit specifically for:
Utilize described local sequence docking to collect mail number from described sliding window starting point, receiving the length that slides backward a chip on signal at every turn, until slide into described sliding window terminating point, every slip is once done related operation one time with receiving signal, obtains corresponding correlation.
With respect to prior art, beneficial effect of the present invention is: use the local sequence docking of the Cyclic Prefix include respective window to collect mail number from sliding window starting point to sliding window terminating point, to do slide relevant, by tap corresponding on the channel impulse response of community, maximum related value location lookup respective window place, if this tap is effective tap, according to the position of this tap, determine the channel impulse response of respective window, even if therefore also can determine accurately the channel impulse response of window in the situation that there is exit window.
Except above beneficial effect, the present invention also has beneficial effect: whether the present invention effectively judges for the tap of each window, by calculating the power of tap and the average power of community, respective window place of each window, carry out odds ratio, the tap that is greater than the corresponding window of predetermined threshold value is effective tap, can fall low noise impact like this, improve the accuracy of exit window judgement.
Except above beneficial effect, the present invention also has beneficial effect: the present invention only carries out corresponding processing to current time slots reception signal just can determine the channel impulse response of respective window, do not need the assistance of other physical processes, do not need to introduce the interface of new parameter and other modules and joint-detection module yet, implementation complexity is low, and real-time is good, adapt to the practical application scene that location of mobile station constantly changes.
Except above beneficial effect, the present invention also has beneficial effect: the present invention obtains after the window with effective tap of each community, determine the significance bit of the channel impulse response of the window with effective tap, and by effective tap zero setting of other windows in significance bit, guarantee to only include effective tap of window separately in the channel impulse response of each window the mutual interference before and after can avoiding between adjacent window.
Except above beneficial effect, the present invention also has beneficial effect: the present invention is based on slip correlation, slip correlation peak is sharp-pointed, and sliding window length is less, and memory data output is low, realizes simple.
Accompanying drawing explanation
Fig. 1 is the structural representation happening suddenly in TD-SCDMA system;
Fig. 2 is the structural representation of the Midamble code that uses of the different windows of same community;
Fig. 3 is the flow chart of steps of the inventive method embodiment;
Fig. 4 is that the inventive method embodiment utilizes the local sequence docking collection of letters number to make the relevant schematic diagram that slides;
Fig. 5 is that the inventive method embodiment is according to the schematic diagram of the position of the tap of the maximum related value location positioning window of window;
Fig. 6 is that the inventive method embodiment is according to the schematic diagram of the channel impulse response significance bit of the location positioning window of effective tap of window;
Fig. 7 is the structural representation of apparatus of the present invention embodiment.
Embodiment
The present invention proposes to determine in a kind of TD-SCDMA system same frequency multi-cell the method and apparatus of window channel impulse response, even also can determine accurately the channel impulse response of window in the situation that there is exit window.
Burst is the most basic structure in TD-SCDMA system, and as shown in Figure 1, a burst is comprised of with protection interval GP the data division of two sections of 352chips and the Midamble code of 144chips part.According in 3GPP standard for the definition of training sequence, between different community in TD-SCDMA system, adopt the basic code of different training sequences (Midamble), the Midamble code that adopts the different cyclic shifts of same Midamble basic code to construct between the different user of same community.The different windows of each community represents the different user in community.
As shown in Figure 2, the Midamble basic code using according to i community constructs by the mode of cyclic shift the Midamble code that i the different windows in community adopts to the structure of the Midamble code that the different windows of same community is used.Set the maximum user number K that i community is configured
iin ，Ze Gai community, the window length of each window is W
i=P/
kthe final stage length of the Midamble basic code of the Midamble1 Jiang Gai community of first window in i ，Gai community is W
ix1 as common composition of a part above of the Midamble basic code of Cyclic Prefix ，Bing Yugai community, make last two segment length of Midamble basic code of the Midamble2 Jiang Gai community of second window in its overall length Wei144，Gai community be W
ix2 and X1 as another part above of the Midamble basic code of Cyclic Prefix ，Bing Yugai community, jointly form, making its overall length is 144, can obtain the Midamble code that in i community, each window adopts by that analogy.
The feature of the Midamble code of the different windows based on each community of above structure, in the method that the present invention proposes, in the burst of the time slot only receiving according to receiving terminal (hereinafter referred to receiving signal), the feature of each Midamble code is determined the channel impulse response of each window in each co-frequency cell, do not need the assistance of other physical processes, do not need to introduce the interface of new parameter and other modules and joint-detection module yet, implementation complexity is low, and real-time is good, adapt to the practical application scene that location of mobile station constantly changes.
Shown in Figure 3, Fig. 3 is the flow chart of the inventive method embodiment, and the present embodiment can comprise the steps:
Step 301: the channel impulse response that obtains each co-frequency cell;
In the burst of the time slot that receiving terminal receives, may include the signal from each co-frequency cell, utilize the Midamble basic code of all co-frequency cells that receiving terminal is known and receive the channel impulse response that signal acquisition receives each co-frequency cell relating in signal, the number of determining the co-frequency cell relating in reception signal is n, and the channel impulse response of each community includes P=128 chip;
If it is synchronous that the subscriber signal between each community within He Ge community keeps, the channel impulse response that each window is corresponding only there will be in this window, receives in signal and the channel impulse response after noise reduction directly can be decomposed into K in this case
jindividual length is W
jwindow, wherein, j=1,2 ... n; K
jbe the maximum number of users that j community is configured, W
jfor window long: W
j=P/K
j.If but each subscriber signal is asynchronous the time of advent, can there is exit window problem and cause window aliasing.Exit window refers to owing to reaching asynchronism(-nization) step and causes that window channel impulse response falls into the situation of other windows.So the channel impulse response for i the community obtaining can not directly be decomposed into K
jindividual length is W
jwindow.
Step 302: intercept the local sequence of each window, doing to received signal slides is correlated with, and determines the maximum related value position that each window is corresponding.
Sliding relevant is to choose sliding window on reception signal, determine slip starting point and sliding window terminating point, then for each window, utilize the local sequence of this window from the sliding window starting point of the sliding window of reception signal, receiving the length that slides backward a chip on signal at every turn, until slide into sliding window terminating point, and every slip once all will with receive signal and do related operation one time, obtain each correlation corresponding with this window.The related operation of two sequences has reflected the similarity degree of two signals, and two sequences are more similar, and correlation is larger.
The local sequence of each window is that the Midamble code by each window is configured is chosen, intercepting starting point and the length of the local sequence of each window are to guarantee local sequence by respective window and receive the signal relevant correlation result obtaining of sliding and in the channel impulse response of respective cell, find the basis of the tap of each window.
The local sequence of utilizing each window to receive signal slide relevant before, and do not know to receive the signal that whether includes the Midamble code that has adopted this window in signal, Fig. 4 is that hypothesis receives three kinds of situations that include the signal of the Midamble code that has adopted window 2 in signal, because the object of the invention is to choose according to known all window Midamble codes the local sequence of respective window, and do and slide relevantly to receiving signal, determine the channel impulse response of all windows that comprise in reception signal.So the selection principle of the local sequence that illustrates window is described, choosing the local sequence of corresponding window when this selection principle is also applicable to receive the signal that does not comprise the Midamble code that has adopted some windows in signal with the window 2 in Fig. 4.
While choosing, consider 2 points: the first point, the local sequence of each window need to comprise the Cyclic Prefix part of the Midamble code of window separately, as shown in Figure 4, includes Cyclic Prefix X2 and the X1 of window 2 in the local sequence of window 2.Like this, slide when relevant utilizing local sequence docking to collect mail number to do, can determine more accurately the original position of the Midamble code that receives window corresponding with corresponding local sequence in signal.Second point, intercepts front several symbols of Midamble code of each window as the local sequence of respective window, rather than the chip of whole length of Midamble code of getting each window is as the local sequence of respective window.In Fig. 4, the intercepted length of the local sequence of window 2 is 128.If the length of the local sequence of window 2 is chosen for whole length 144 of the Midamble code of window 2, utilize so the local sequence docking of window 2 to collect mail number to slide in the result of relevant each correlation obtaining, not only in the original position of window 2, (situation one of Fig. 4 is the situation of exit window before window 2 occurs, the original position that represents window 2 has adopted arrow logo in Fig. 4) there is theoretic maximum related value, namely there is theoretic maximum related value during the X2 section aligned of the X2 of the local sequence of window 2 part and window 2, be called real peak, and, the process that the local sequence of window 2 starts to slide backward from sliding window starting point, when the X1 section aligned of the X1 of the local sequence of window 2 part and window 1, also there will be larger correlation, be called ghost peak, the two correlation differs less, indistinguishable under the impact of noise.If by the local sequence brachymemma of window 2, ghost peak increases apart from meeting with very peak-to-peak numerical difference between so, is conducive to detecting of real peak.If the local sequence of window 2 only intercepts X2 part, utilize so the local sequence docking of window 2 to collect mail number to slide in the result of relevant each correlation obtaining and just there will not be ghost peak, but if the length of the local sequence of window 2 is too short, so to receive the signal obviously decline of antimierophonic ability when relevant of sliding.Therefore, the length of local sequence is chosen the characteristic that should consider noiseproof feature and suppress ghost peak.
As shown in Figure 4, generally, the state that receives all windows in signal can be divided into three kinds of situations, the window of exit window before occurring is, the window of exit window and the window of exit window does not occur after occurring, but for a window, can only be in a kind of state wherein in the burst of a time slot.In order to detect the window of various states, receive choosing of sliding window on signal and be also the local sequence that guarantees by respective window and the reception signal relevant correlation result obtaining of sliding and in the channel impulse response of respective cell, find the key of the tap of each window.
In embodiments of the invention 1, shown in Figure 4, the Midamble of usining in reception signal starting point is partly as Midamble reference point, namely receive the position of first chip of Midamble part of signal as Midamble reference point, sliding window starting point is in Midamble reference point, to have got forward the data chips of a threshold length, setting this threshold value is Y, the value of Y should guarantee that sliding window starting point comprises the original position of the window of the front exit window of generation in all communities backward, the situation one of Fig. 4 is the situation of exit window before window 2 occurs, the original position of window 2 has adopted arrow logo in Fig. 4, sliding window terminating point is to have got backward and the be separated by Midamble chip of the long length with a threshold value sum of the window of a window of Midamble reference point in Midamble reference point, apart from W+Y length of Midamble reference point, so the value of Y also should guarantee sliding window terminating point and comprise forward the original position that the window of rear exit window occurs in all communities, situation three in Fig. 4 is situations of exit window after window 2 occurs, and the original position of window 2 has also adopted arrow logo.
Sliding window on local sequence and reception signal is implemented to slide relevant after determining, sliding window length is W+2Y.Generally, the exit window length of a window can not surpass the length of a window, so in the present embodiment 1, the value of Y is set to a long W of window, so the total length of sliding window is three times of window length, sliding window length equals 3W.Utilize the local sequence docking collection of letters number of each window to slide relevant, capital obtains 3W correlation, find the maximum related value of each window, and record the maximum related value of each window with respect to the position of Midamble reference point, be called the maximum related value position of respective window.The peak value of the maximum related value of each window is generally very sharp-pointed, and it is less to receive the sliding window length of choosing on signal, and memory data output is low, realizes simple.
If include the signal of the Midamble code that has adopted some windows in reception signal, utilize so the local sequence of this window to slide relevant to reception signal, in the 3W an obtaining correlation, having an obvious especially sharp-pointed correlation occurs, this obvious especially sharp-pointed correlation is the maximum in this 3W correlation, records the maximum related value of this window with respect to the position of Midamble reference point.As shown in Figure 4, if receive the signal that includes the Midamble code that adopts window 2 in signal, window of tube 2 is not in which kind of situation so, and the maximum related value of window 2 all appears at the original position of the window 2 in corresponding situation.
If do not comprise the signal of the Midamble code that has adopted some windows in reception signal, due to the noisy interference of meeting, utilize so the local sequence of this window to slide relevant to reception signal, the 3W that also can an obtain correlation, wherein also have a maximum correlation and occur, also record the maximum related value of this window with respect to the position of Midamble reference point.
Step 303: according to the state of the maximum related value location positioning respective window of each window;
If each maximum related value position of window with effective tap of record is before Midamble reference point in step 302, there is front exit window in corresponding window; Referring to situation in Fig. 5 one, if the maximum related value position of the window 2 of record, before Midamble reference point, so just can determine that front exit window has occurred window 2 in step 302; Now the maximum related value position of window 2 is before Midamble reference point, and the distance apart from an exit window lead of Midamble reference point, generally, before occurring, the exit window length of the window of exit window can be not long over a window, so this exit window lead meets: 0 < exit window lead≤W.
If each maximum related value position of window with effective tap of record is just in time in the position of Midamble reference point in step 302, there is not exit window in corresponding window; But consider the delay character of wireless channel, if so in step 302 each maximum related value position of window with effective tap of record after Midamble reference point, as long as in the scope of a window length, so also can determine that exit window does not occur corresponding window after Midamble reference point; Referring to situation in Fig. 5 two, if the maximum related value position of the window 2 of record is after Midamble reference point in step 302, and the distance apart from an exit window retardation 1 of Midamble reference point, and this exit window retardation 1 meets: 0 < exit window retardation 1 < W, so also can determine that exit window does not occur window 2
If outside the long scope of the maximum related value position of window that in step 302, each of record has effective tap window Midamble reference point after, there is rear exit window in window accordingly; Referring to situation in Fig. 5 three, if the maximum related value position of the window 2 of record is after Midamble reference point in step 302, and the distance apart from an exit window retardation 2 of Midamble reference point, and this exit window retardation meets: W≤exit window retardation 2, so just can determine that rear exit window has occurred window 2.Generally, after occurring, the exit window length of the window of exit window can be not long over a window yet, so this exit window retardation 2 meets: W≤exit window lead < 2W.
Step 304: search the tap corresponding with each window according to the relative position relation of the maximum related value position of each window and Midamble reference point on the channel impulse response of each community, window place;
As shown in Figure 5, for the window 2 in Yi Ge community, maximum number of user in known this community is that the length of the channel impulse response of K He Gai community is 128, first suppose that exit window does not all occur all windows in this community, the channel impulse response of Xian Jianggai community is directly decomposed into the original window that K length is W, W=128/K.The previous window that each window in this community is adjacent with this window and an adjacent rear window be first window of adjacent Chuan，Qie Gai community and last window adjacent window each other each other, and namely window K is the previous window of the window 1 adjacent with window 1.
According to searching the tap corresponding with window 2 in the channel impulse response of the maximum related value position of window 2 and the relative position relation ，Gai community of Midamble reference point:
Referring to situation in Fig. 5 one, if the maximum related value position of the window 2 of record is before Midamble reference point in step 302, and the distance apart from an exit window lead of Midamble reference point, and this exit window lead meets: 0 < exit window lead≤W, so on the channel impulse response of window 2 communities, place, using the starting point of original window 2 of window 2 correspondences as the reference point of window 2 oneself, be called window 2 reference points (the circular stain place in the situation one of Fig. 5), in the previous window original window 1 of the original window 2 before window 2 reference points, it apart from the tap corresponding to position of an identical exit window lead distance of window 2 reference point, is exactly the tap of window 2 correspondences that will search, be called the tap of window 2,
If the maximum related value position of window that in step 302, each of record has effective tap is just in time in the position of Midamble reference point, on the channel impulse response of window 2 communities, place, in tap corresponding to the position of window 2 reference points, be exactly the tap of window 2 so;
Referring to situation in Fig. 5 two, if the maximum related value position of the window 2 of record is after Midamble reference point in step 302, and the distance apart from an exit window retardation 1 of Midamble reference point, and this exit window retardation 1 meets: 0 < exit window retardation 1 < W, so on the channel impulse response of window 2 communities, place, in original window 2 after window 2 reference points, apart from the tap corresponding to position of the distance of an identical exit window retardation 1 of window 2 reference point, be exactly the tap of window 2;
Referring to situation in Fig. 5 three, if the maximum related value position of the window 2 of record is after Midamble reference point in step 302, and the distance apart from an exit window retardation 2 of Midamble reference point, and this exit window retardation meets: W≤exit window retardation 2, so on the channel impulse response of window 2 communities, place, in a rear window original window 3 of the original window 2 after window 2 reference points, apart from the tap corresponding to position of the distance of an identical exit window retardation 2 of window 2 reference point, be exactly the tap of window 2.
Step 305: judge whether tap corresponding to each window in each co-frequency cell is effective tap of respective window, if so, enters step 306;
In this step, if comprise the signal of the Midamble code that has adopted some windows in reception signal, the tap of this window that the maximum related value of doing according to the local sequence docking collection of letters number that utilizes this window the relevant acquisition of sliding so finds is exactly effective tap of this window; If do not comprise the signal of the Midamble code that has adopted some windows in reception signal, the tap of this window that the maximum related value of doing according to the local sequence docking collection of letters number that utilizes this window the relevant acquisition of sliding so finds is exactly the tap that receives the noise generation in signal.
In specific embodiments of the invention, judge that the step of effective tap is as follows:
Steps A 1: the power that calculates the tap of each window;
Steps A 2: the average power of the whole channel impulse responses of the power of this tap and current area is made to ratio;
Steps A 3: judge whether this ratio is greater than a default thresholding, if be greater than default thresholding, effective tap that this tap is respective window.
Find so all windows with effective tap in each co-frequency cell, each has the window of effective tap mark, and records effective tap of each window in the channel impulse response Shang position of current area.
In this step, it should be noted that, if the determination result is NO for step 305, stop current flow process.
Step 306: determine that in the channel impulse response of each community each has the channel impulse response of the window of effective tap;
For each community, through above step, known in each community all windows with effective tap and effectively tap in the channel impulse response Shang position of current area, take so the position of this effective tap is starting point, choose backward the chip of the long length of a window as the significance bit of the channel impulse response of respective window, and by effective tap zero setting of other windows in the significance bit of the channel impulse response of this window.
Window 2 in corresponding diagram 4 and Fig. 5, determined that window 2 has effective tap, as shown in Figure 6, which kind of situation there is not in window of tube 2, be all using effective tap of window 2 in the channel impulse response Shang position of the current area at window 2 places the starting point as the significance bit of the channel impulse response of window 2, from this starting point, choose backward the chip of the long length of a window as the significance bit terminating point of the channel impulse response of window 2, the significance bit of the channel impulse response of window 2 just can be determined so.
If the position of effective tap of window 2 is dropped on original window 1, as the situation one in Fig. 6, if also include so effective tap of window 1 in the significance bit of the channel impulse response of the window 2 obtaining before, so should be by effective tap zero setting of window 1 in the significance bit of the channel impulse response of window 2, guarantee only to comprise effective tap of window 2 oneself in window 2; If also comprise the tap of window 2 in the significance bit of the channel impulse response of window 1, so should be by effective tap zero setting of window 2 in the significance bit of the channel impulse response of window 1, guarantee only to comprise effective tap of window 1 oneself in window 1.
If the position of effective tap of window 2 is dropped on original window 3, as the situation three in Fig. 6, if in the significance bit of the channel impulse response of the window 2 obtaining before, also include so window 3 even window 4 (position of the original window 4 of window 4 correspondences is after original window 3, in Fig. 6, do not illustrate) effective tap, so should be by even effective tap zero setting of window 4 of window 3 in the significance bit of the channel impulse response of window 2, guarantee only to comprise effective tap of window 2 oneself in window 2; If also comprise the tap of window 2 in the significance bit of the channel impulse response of window 3, so should be by effective tap zero setting of window 2 in the significance bit of the channel impulse response of window 3, guarantee only to comprise effective tap of window 3 oneself in window 3; A general window only may be fallen the front exit window of generation in the previous window adjacent with it, or fall the rear exit window of generation in a rear window adjacent with it, can not fall the situation in other window, so can not comprise effective tap of window 2 in the significance bit of the channel impulse response in window 4, the mutual interference before and after therefore can avoiding by method of the present invention between adjacent window.
The embodiment of the invention also discloses the device of determining window channel impulse response in a kind of TD-SCDMA system same frequency multi-cell, shown in figure 7, structural representation for device embodiment, the device of the present embodiment specifically can comprise: comprise channel estimating unit 701, slip correlation unit 702, Window state determining unit 703, window tap determining unit 704, judging unit 705 and channel impulse response determining unit 706
Described channel estimating unit 701, for, the channel impulse response of each co-frequency cell obtained;
Described slip correlation unit 702, for, the local sequence of each window in described each co-frequency cell of intercepting, to receive signal do slide relevant, maximum related value position corresponding to each window described in determining;
Preferably, described slip correlation unit concrete 702 specifically can be for:
To be separated by forward the chip of a threshold length as sliding window starting point with described training sequence reference point, to be separated by backward the chip of the long length with described threshold value sum of the window of a described window as sliding window terminating point with described training sequence reference point, utilize described local sequence docking to collect mail number from described sliding window starting point, receiving the length that slides backward a chip on signal at every turn, until slide into described sliding window terminating point, every slip is once done related operation one time with receiving signal, obtains corresponding correlation.
Described Window state determining unit 703, for, according to the state of the maximum related value location positioning respective window of described each window;
Described Window state determining unit 703 specifically for: if the maximum related value position of described window before described training sequence reference point, determines that the state of corresponding window is front exit window; If the state that corresponding window in described training sequence reference point or after described training sequence reference point in the long scope of window, is determined in the maximum related value position of described window is exit window not; If outside the scope of the maximum related value position of described window window length after described training sequence reference point, determine that the state of corresponding window is rear exit window;
Described window tap determining unit 704, be used for, according to the relative position relation of the training sequence reference point of maximum related value position corresponding to described each window and described reception signal, in the channel impulse response of described each community, window place, the tap of searching each window;
Described judging unit 705, be used for, whether the ratio of the average power of the whole channel impulse responses of power and current area of the tap of described each window of judgement is greater than predetermined threshold value, if, effective tap that the tap of determining corresponding window is respective window, the position of effective tap of described each window of record;
Described channel impulse response determining unit 706, be used for, in the channel impulse response of each community, window place, determine that each has the channel impulse response of the window of effective tap: from thering is the position of effective tap of window of effective tap, intercept the chip of the long length of window of this community, window place as the significance bit of the channel impulse response of this window, and by effective tap zero setting of other windows in the significance bit of the channel impulse response of this window.
Preferably, the Cyclic Prefix part that the local sequence of each window in described each co-frequency cell comprises the training sequence that respective window adopts, and length is front several chips of the local sequence that adopts of respective window.
Adopt the disclosed device of the embodiment of the present invention, the mutual interference before and after can avoiding between adjacent window.
Below be only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, do not departing under the prerequisite of principle of the present invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.
Claims (8)
1. in TD-SCDMA system same frequency multi-cell, determine a method for window channel impulse response, it is characterized in that, comprising:
Obtain the channel impulse response of each co-frequency cell;
The local sequence of each window in described each co-frequency cell of intercepting, to receive signal do slide relevant, maximum related value position corresponding to each window described in determining;
According to the state of the maximum related value location positioning respective window of described each window;
According to the relative position relation of the training sequence reference point of maximum related value position corresponding to described each window and described reception signal, in the channel impulse response of described each community, window place, the tap of searching each window;
Whether the ratio of the average power of the whole channel impulse responses of power and current area of the tap of described each window of judgement is greater than predetermined threshold value, if, effective tap that the tap of determining corresponding window is respective window, the position of effective tap of described each window of record;
In the channel impulse response of each community, window place, determine that each has the channel impulse response of the window of effective tap: from thering is the position of effective tap of window of effective tap, intercept the chip of the long length of window of this community, window place as the significance bit of the channel impulse response of this window, and by effective tap zero setting of other windows in the significance bit of the channel impulse response of this window.
2. method according to claim 1, is characterized in that,
Described in described basis, the state of the maximum related value location positioning respective window of each window is specially:
If the maximum related value position of described window before described training sequence reference point, determines that the state of corresponding window is front exit window; If the state that corresponding window in described training sequence reference point or after described training sequence reference point in the long scope of window, is determined in the maximum related value position of described window is exit window not; If outside the scope of the maximum related value position of described window window length after described training sequence reference point, determine that the state of corresponding window is rear exit window.
3. method according to claim 1, it is characterized in that, the Cyclic Prefix part that the local sequence of each window in described each co-frequency cell comprises the training sequence that respective window adopts, and length is front several chips of the local sequence that adopts of respective window.
4. method according to claim 1, is characterized in that, described to receive signal and do to slide and be relevantly:
To be separated by forward the chip of a threshold length as sliding window starting point with described training sequence reference point, will be separated by backward the chip of the long length with described threshold value sum of the window of a described window as sliding window terminating point with described training sequence reference point;
Utilize described local sequence docking to collect mail number from described sliding window starting point, receiving the length that slides backward a chip on signal at every turn, until slide into described sliding window terminating point, every slip is once done related operation one time with receiving signal, obtains corresponding correlation.
5. in a TD-SCDMA system same frequency multi-cell, determine the device of window channel impulse response, it is characterized in that, comprise channel estimating unit, slip correlation unit, Window state determining unit, window tap determining unit, judging unit and channel impulse response determining unit
Described channel estimating unit, for, the channel impulse response of each co-frequency cell obtained;
Described slip correlation unit, for, the local sequence of each window in described each co-frequency cell of intercepting, to receive signal do slide relevant, maximum related value position corresponding to each window described in determining;
Described Window state determining unit, for, according to the state of the maximum related value location positioning respective window of described each window;
Described window tap determining unit, be used for, according to the relative position relation of the training sequence reference point of maximum related value position corresponding to described each window and described reception signal, in the channel impulse response of described each community, window place, the tap of searching each window;
Described judging unit, be used for, whether the ratio of the average power of the whole channel impulse responses of power and current area of the tap of described each window of judgement is greater than predetermined threshold value, if, effective tap that the tap of determining corresponding window is respective window, the position of effective tap of described each window of record;
Described channel impulse response determining unit, be used for, in the channel impulse response of each community, window place, determine that each has the channel impulse response of the window of effective tap: from thering is the position of effective tap of window of effective tap, intercept the chip of the long length of window of this community, window place as the significance bit of the channel impulse response of this window, and by effective tap zero setting of other windows in the significance bit of the channel impulse response of this window.
6. device according to claim 5, is characterized in that, described Window state determining unit specifically for:
If the maximum related value position of described window before described training sequence reference point, determines that the state of corresponding window is front exit window; If the state that corresponding window in described training sequence reference point or after described training sequence reference point in the long scope of window, is determined in the maximum related value position of described window is exit window not; If outside the scope of the maximum related value position of described window window length after described training sequence reference point, determine that the state of corresponding window is rear exit window.
7. device according to claim 5, it is characterized in that, the Cyclic Prefix part that the local sequence of each window in described each co-frequency cell comprises the training sequence that respective window adopts, and length is front several chips of the local sequence that adopts of respective window.
8. device according to claim 5, is characterized in that, described slip correlation unit specifically for:
To be separated by forward the chip of a threshold length as sliding window starting point with described training sequence reference point, will be separated by backward the chip of the long length with described threshold value sum of the window of a described window as sliding window terminating point with described training sequence reference point,
Utilize described local sequence docking to collect mail number from described sliding window starting point, receiving the length that slides backward a chip on signal at every turn, until slide into described sliding window terminating point, every slip is once done related operation one time with receiving signal, obtains corresponding correlation.
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| CN101022285A (en) * | 2007-03-20 | 2007-08-22 | 中兴通讯股份有限公司 | Co-channel adjacent cell channel estimating method at the time of multi-cell union detection in TD SCDMA system |
| CN101252554A (en) * | 2008-01-08 | 2008-08-27 | 北京天碁科技有限公司 | Method and apparatus for postprocessing channel estimation |
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