US20050221848A1 - Apparatus and method for performing initial cell search in wireless communication systems - Google Patents
Apparatus and method for performing initial cell search in wireless communication systems Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
- H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7073—Synchronisation aspects
- H04B1/70735—Code identification
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7073—Synchronisation aspects
- H04B1/7083—Cell search, e.g. using a three-step approach
Definitions
- FIG. 1 illustrates a wireless communication system.
- the communication system has a plurality of base stations 2 1 - 2 n ( 2 ).
- Each base station 2 communicates with user equipment (UEs) 4 1 - 4 N ( 4 ) within its operating area or cell 6 1 - 6 N ( 6 ).
- UEs user equipment
- the UE 14 determines the base station 12 to be synchronized to by searching the PSCH for received PSCs, such as using a matched filter.
- An example of the results of such a search are shown in FIG. 3 .
- peaks 26 1 - 26 2 occur in the PSCH where there is a high correlation with the PSC code.
- the search results are accumulated over multiple frames to improve accuracy. Using the accumulated results, the PSC peak locations are determined in the PSCH.
- FIG. 1 is an illustration of a wireless communication system.
- FIG. 4 is a block diagram of the initial cell search system of the present invention.
- the position of the maximum average of the frames is determined and its value compared with a determined threshold.
- the threshold is based on the noise level (i.e., interference plus thermal noise) at the receiver.
- the noise estimator 24 has an auxiliary HGC (not shown) that is based on a code which has very low cross correlation with the PSC and the SSCs.
- the noise estimator 24 HGC calculates a noise estimate for every chip in the system frame.
- the noise estimator 24 iterates over the same number of frames as the HGC 21 and averages several of the noise estimates in a window around the estimated PSCH location.
- the window size is preferably about 128, i.e., 64 chips on both sides of the PSCH location. As those having skill in the art know, the window size may be larger or smaller than 128.
- the t offset, scrambling code group number, SSCs, and the location of the PSC are then forwarded to the step 3 processor 16 .
- the step 3 processor 16 coupled to the step 2 processor 14 , retrieves the midambles and primary scrambling code that are used by the UE.
- the code group number retrieved by the step 2 processor 14 is associated with four cell parameters. Therefore, identification of the code group number identifies the midamble codes used by the cell.
- the flow diagram for the initial cell search system is illustrated in FIG. 7 .
- the UE receives the input signal over the common downlink channel (step 601 ).
- the step 1 processor 12 detects the location of the PSC associated with the strongest base station (step 602 ).
- the step 1 processor 12 forwards the PSC to the cancellation device 18 (step 603 ).
- the cancellation device 18 then subtracts the PSC detected from the step 1 processor 12 from the input signal I (step 604 ) and forwards this modified signal to the step 2 processor 14 (step 605 ).
- the step 2 processor 14 retrieves the SSCs and determines t offset and the code group number associated with the strongest base station (step 606 ).
- a second embodiment is illustrated in FIG. 8 . Similar to the system of FIG. 1 , the system of this second embodiment utilizes a cancellation device 18 2 to subtract the PSC and SSCs from the input signal I before processing by the step 3 processor 16 . Step 2 does not receive a PSC removed input signal, instead the modified input signal to the step 3 processor 16 is able to more accurately detect the midamble and code group of the detected base station.
- a third embodiment is illustrated in FIG. 9 .
- This third embodiment utilizes the cancellation devices 18 1 and 18 2 to improve the accuracy of the initial cell search system 10 .
- the cancellation device 18 1 removes the PSC from the detected location in the input signal prior to the step 2 processor 14 .
- the cancellation device 18 2 removes the SSCs prior to the step 3 processor 16 .
Abstract
The system and method of the present invention establishes a communication link between a user equipment (UE) and a base station in a communication system having a plurality of base stations which each transmit a common primary synchronization code (PSC) in a primary synchronization channel in conjunction with a base station specific secondary synchronization code (SSC) within a system frame, which receives with the UE an input signal including the PSC and SSC from at least one of the base stations. The UE analyzes the input signal to detect any received PSCs within a selected time period which has duration corresponding to the length of a system frame and determining a relative location of a strongest PSC within the selected time period. The input signal is then processed to remove the PSC from at least the determined PSC location. A secondary synchronization code (SSC) is then detected for the determined location from the processed signal. The communication link is then established using the detected SSCs.
Description
- This application is a continuation of U.S. patent application Ser. No. 09/998,885, filed on Oct. 31, 2001, which claims the benefit of U.S. Provisional Application Ser. No. 60/300,412, filed on Jun. 22, 2001, which are incorporated by reference as if fully set forth.
- The present invention relates to user equipment (UE) synchronization to a base station. More specifically, the present invention relates to an improved initial cell search method and system.
-
FIG. 1 illustrates a wireless communication system. The communication system has a plurality of base stations 2 1-2 n (2). Eachbase station 2 communicates with user equipment (UEs) 4 1-4 N (4) within its operating area or cell 6 1-6 N (6). - When a UE 4 is first activated, it is unaware of its location and which base station 2 (or cell 6) to communicate. The process where the UE 4 determines the cell 6 to communicate with is referred to as “cell search.”
- In typical code division multiple access (CDMA) communication systems, a multi-step process is used for cell search. For step one, each
base station 2 transmits the same primary synchronization code (PSC) in a primary synchronization channel (PSCH). In a time division duplex (TDD) communication system using CDMA, the PSCH is one timeslot out of fifteen forcase 1 cell search (as shown inFIG. 2A ), such as slot 0 or in general K, or two timeslots forcase 2 cell search (as shown inFIG. 2B ), such as slots 0 or in general K and K+8 and 8. Eachbase station 2 transmits the same PSC in the PSCH timeslot(s). To reduce interference between secondary synchronization codes (SSCs) used in step two, each PSC is transmitted at a different time offset. The PSC offsets are at a set number of chips. - The UE 14 determines the
base station 12 to be synchronized to by searching the PSCH for received PSCs, such as using a matched filter. An example of the results of such a search are shown inFIG. 3 . As shown inFIG. 3 , peaks 26 1-26 2 occur in the PSCH where there is a high correlation with the PSC code. Typically, the search results are accumulated over multiple frames to improve accuracy. Using the accumulated results, the PSC peak locations are determined in the PSCH. - Referring back to
FIG. 2A and 2B , along with each base station's transmitted PSC, eachbase station 2 also simultaneously transmits secondary synchronization codes (SSCs), such as three, for bothTDD case 1 andcase 2. The SSCs sent by eachbase station 2 are used to identify certain cell parameters, such as the code group and frame timing used by the cell 6. The UE 4 typically uses a correlator to detect the SSCs and the data modulated on them at each PSC peak identified in step I. The UE 4 reads the broadcast control channel. In TDD step III for both types I and II, typically, the UE 4 detects the midamble used in the broadcast channel and subsequently reads the broadcast channel. - A drawback of the initial cell search system described above is that the performance of the second step (SSC detection) is governed by the quality of the received signal which could result in false detections if this signal is of poor quality. In past systems, the second step, receives no benefit from successful execution of step I.
- Accordingly, there is a need for an initial cell search system wherein the second step's performance is not solely governed by the received input signal, providing more accurate SSC detection.
- The system and method of the present invention establishes a communication link between a user equipment (UE) and a base station in a communication system having a plurality of base stations which each transmit a common primary synchronization code (PSC) in a primary synchronization channel in conjunction with a base station specific secondary synchronization code (SSC) within a system frame, which receives with the UE an input signal including the PSC and SSC from at least one of the base stations. The UE analyzes the input signal to detect any received PSCs within a selected time period which has duration corresponding to the length of a system frame and determining a relative location of a strongest PSC within the selected time period. The input signal is then processed to remove the PSC from at least the determined PSC location. A secondary synchronization code (SSC) is then detected for the determined location from the processed signal. The communication link is then established using the detected SSCs.
-
FIG. 1 is an illustration of a wireless communication system. -
FIGS. 2A and 2B are illustrations of the physical synchronization channel (PSCH) forcase 1 andcase 2, respectively. -
FIG. 3 is an illustration of peaks in a PSCH. -
FIG. 4 is a block diagram of the initial cell search system of the present invention. -
FIG. 5 is an exemplary block diagram of astep 2 processor. -
FIG. 6 is an exemplary block diagram of astep 3 processor. -
FIG. 7 is a flow diagram of the procedure implemented by the initial cell search system of the present invention. -
FIG. 8 is a block diagram of a second embodiment of the initial cell search system. -
FIG. 9 is a block diagram of a third embodiment of the initial cell search system. - The preferred embodiments will be described with reference to the drawing figures where like numerals represent like elements throughout.
- The initial
cell search system 10 in accordance with the preferred embodiment of the present invention is illustrated inFIG. 4 . Thesystem 10 comprises astep 1processor 12, acancellation device 18, astep 2processor 14, and astep 3processor 16, to accomplish initial synchronization between a user equipment (UE) and a base station. -
Step 1 of the initial cell search algorithm is accomplished using thestep 1processor 12.FIG. 4 shows one implementation of astep 1 processor, although others may be used. Thestep 1processor 12 comprises a Hierarchical Golay Correlator (HGC) 21 and aPSC decision device 22. The purpose of thestep 1processor 12 is to find the strongest base station's PSC over a frame or multiple frames worth of samples. A chip-sampled input signal I is received by the UE and processed by the HGC 21. The HGC 21 is a reduced complexity implementation of the correlation process between PSC and the input signal I at consecutive chip locations. The output of the HGC 21 represents the magnitudes of the detected PSC power levels for those base stations detected by the HGC 21. The base stations' PSCs with a high received power level appear as peaks in the frame. The outputs from the HGC 21 are output to thePSC decision device 22. - The
PSC decision device 22, coupled to theHGC 21, receives the correlation values output by the HGC 21 for each chip in a frame worth of chips. A frame's worth of chips is preferably equivalent to the system frame, which by way of example, is equivalent to 38,400 chips. As those having skill in the art know, the system frame can be more or less than that which is used in this disclosure. - The
decision device 22 stores each chip correlation value from theHGC 21 over a predetermined number of frames N and averages each chip's correlation values. As an example, a system frame is 4 chips long, and N=2. TheHGC 21 outputs the correlation values A1, B1, C1, and D1, respectively for each of the four chips. Thedecision device 22 stores these values and receives the output of the next frame's correlation values for each chip from theHGC 21, which are A2, B2, C2, D2. Each chip''correlation values are then averaged, (i.e., A1,+A2/2; B1+B2/2; C1+C2/2; D1+D2/2). - Once the
decision device 22 finds the average correlation value for each average correlation chip in a frame, the position of the maximum average of the frames is determined and its value compared with a determined threshold. The threshold is based on the noise level (i.e., interference plus thermal noise) at the receiver. Thenoise estimator 24 has an auxiliary HGC (not shown) that is based on a code which has very low cross correlation with the PSC and the SSCs. Thenoise estimator 24 HGC calculates a noise estimate for every chip in the system frame. Thenoise estimator 24 iterates over the same number of frames as theHGC 21 and averages several of the noise estimates in a window around the estimated PSCH location. The window size is preferably about 128, i.e., 64 chips on both sides of the PSCH location. As those having skill in the art know, the window size may be larger or smaller than 128. - If the maximum average is greater than the threshold, the
decision device 22 determines whether the transmission pattern of the base station associated with the maximum average location iscase 1 orcase 2. This determination is made by comparing the correlation value of the chip at the maximum location +(8*2560) or maximum location +(7*2560). If this value is greater than the threshold, then the transmission pattern iscase 2. Otherwise, the transmission iscase 1. - If the maximum location value is less than the threshold, the
step 1processor 12 continues processing the input signal I until a correlation value greater than the threshold is found or a failed condition is met. As those skilled in the art know, thedecision processor 22 may utilize any of a number of methods for determining the location of the strongest PSC code. Once the maximum location value is found, thedecision processor 22 forwards the location and the PSC to thecancellation device 18 and thestep 2processor 14. - The
cancellation device 18, coupled to thestep 1processor 12 and thestep 2processor 14, takes the maximum location, the PSC and the input signal I and subtracts the PSC from the input signal I. This subtraction eliminates the PSC from the chip at the maximum location in the input signal I. The subtraction of the PSC from the input signal I can be done by one of several cancellation methods, such as interference cancellation. Using interference cancellation, the PSC is converted, using an interference construction device (not shown), into an estimate of its contribution to the input signal I. The received PSC's contribution is subtracted, such as by a subtractor. The resulting signal has the PSC's contribution removed from the input signal I at the maximum location. In code multiplexing systems, one code appears as noise to other codes. Accordingly, the PSC is essentially noise to the SSC. As a result, when the PSC is cancelled from the input signal I, thestep 2processor 14 is able to locate the SSC and slot offset with greater accuracy and speed. - The
step 2processor 14, coupled to thecancellation device 18, thestep 1processor 12 and thestep 3processor 16, receives the modified input signal from thecancellation device 18 and the location of the PSC from thestep 1processor 22. - One example of a
step 2processor 14 is illustrated inFIG. 5 , although others may be used. Thestep 2processor 14 comprisescorrelator 31, a fast Hadamard transform device (FHT) 33,phase estimator device 37, aderotate device 34, anaccumulator 36, and adecision device 39. Since the location of the PSC has been determined by thestep 1processor 12, then thestep 2processor 14 needs only to search for the SSCs in the maximum location input from thestep 1processor 12. In this step, the UE identifies the code group and the toffset associated with the base station at the maximum location. Thestep 2processor 14 also determines the frame index number within the interleaving period of two frames and it determines the slot index (K or K+8). As those skilled in the art know, the toffset determined in this step allows the UE to synchronize to the slot bo cr(i)=c1(i)*z(i),i= . . . ,255 undary. The modified input signal and the position of the PSC are input to thecorrelator 31. Thecorrelator 31, coupled to theFHT 33 and thecancellation device 18, correlates the received input signal with the length 256 chip code at the PSC position to obtain 16 correlation values. This code, CR, is obtained from chip by chip multiplication of first SSC, C1, and a masking sequence, Z. This is shown below:
c r(i)=c 1(i)*z(i),i=0, . . . ,255Equation 1
The 16 complex correlation values, Rc (K) are obtained using the above code. Rc (K) is obtained by the following Equation 2:
where tcp is the PSC position obtained from thestep 1processor 12 and N is the maximum number of PSCH time slots used for averaging. - The correlation values obtained at the output of the
correlator 31 are applied to theFHT 33. TheFHT 33, coupled to thecorrelator 31 and aderotate device 34, obtains 16 complex correlation values that correspond to the correlation of 16 SSCs and the received signal. That is:
As those skilled in the art know, taking FHT of Rc(K)'s is equivalent to the correlation of unmasked SSCs with the received signal. This is possible due to the special structure of the 16 SSCs. Please note that acase 1 signal uses six (6) SSCs and acase 2 signal uses twelve (12) SSCs. Four (4) SSCs are unused. - The
phase estimator 37 receives the modified chip sampled received signal, as well as the PSC position from thestep 1processor 12. The output of thestep 1HGC 21 at the PSC position corresponds to the correlation of the PSC with the received signal at the PSC position. This complex correlation value is the input to thephase estimator 37. In thisphase estimator 37, the complex correlation value is normalized and then conjugated. The phase estimation is necessary for the derotation of the SSCs. - The
derotate device 34, coupled to thephase estimator 37 and theFHT 33, receives the 16 SSCs from theFHT 33 and the phase estimation from thephase estimator 37. Thederotate device 34 derotates the output of theFHT 33. The derotation phase is the phase of the PSC. The complex correlation values are complex multiplied with the phase. - The derotated correlation values are then forwarded to the
accumulator 36. Theaccumulator 36 is coupled to thederotate device 34 and thestep 2decision device 39. The derotated correlation values are added coherently with a period of two (for case 1) or four (for case 2), for N iterations in accordance with equation 4:
r a 1(k,n)=r a 1(k,n−1)+rd(k,n)δ(1−n mod L), k=0, . . . , K; n=0, . . . , N; 1=0, . . . L Equation 4
where N is the maximum number of iterations to obtain a reliable signal value, K is the number SSCs used (K=6 forcase 1 and K=12 for case 2) and L is periodicity of the PSCH (L=2 forcase 1 and L=4 for case 2). These correlation values are initially set to zero. The decision variables are formed from the correlation values according to the SSC transmission patterns. - The decision variables obtained in the
accumulator 36 are forwarded to thedecision device 39. There are 64 decision variables forcase 1, 32 code groups and 2 frames indices. Forcase 2, there are 128 decision variables, 32 code groups, 2 frame indices and 2 slots (K or K+8). Thedecision device 39 compares all the decision variables sequentially (one by one). This scheme is efficient since the number of decision variables is not large and the scheme can be implemented without much complexity. The transmission pattern that the maximum decision variable belongs to indicates the code group number ofcase 1 andcase 2 and PSCH slot index forcase 2. - The toffset, scrambling code group number, SSCs, and the location of the PSC are then forwarded to the
step 3processor 16. Thestep 3processor 16, coupled to thestep 2processor 14, retrieves the midambles and primary scrambling code that are used by the UE. The code group number retrieved by thestep 2processor 14 is associated with four cell parameters. Therefore, identification of the code group number identifies the midamble codes used by the cell. The four cell parameters associated with the code group are cycled through System Frame Numbers (SFNs) as depicted in Table 1.TABLE 1 Cell Parameter Cell Cell Code (initially Parameter Parameter Group assigned) ( SFN mod 2 = 0)( SFN mod 2 = 1)i = 1, . . . , 32 4(i − 1) 4(i − 1) 4(i − 1) + 1 4(i − 1) + 1 4(i − 1) + 1 4(i − 1) 4(i − 1) + 2 4(i − 1) + 2 4(i − 1) + 3 4(i − 1) + 3 4(i − 1) + 3 4(i − 1) + 2 -
FIG. 6 illustrates anexemplary step 3processor 16. Although astep 3 processor is illustrated, anystep 3 processor may be utilized. Thestep 3processor 16 comprises acorrelation device 41, anaccumulation device 42, and adecision device 43. Thecorrelation device 41 is forwarded to the code group and frame index from thestep 2processor 14, and the PSC position from thestep 1processor 12. A periodic window size pWS and multipath window size mpWS are also input to thecorrelation device 41. The input signal I is correlated with the four (4) midambles that are associated with the code group by thecorrelation device 41. The correlation is performed at WS3 calculated candidate midamble locations on the P-CCPCH which are determined by the toffset of the code group, the periodic window size pWS and the multipath window size mpWS; where WS3=pWS+2mpWS. - The basic midamble code toggles with the SFN (odd/even). If the SFN is even, the
correlation device 41 correlates against the basic midamble code. If the SFN is odd, thecorrelation device 41 correlates against the cycled midamble code. For example, in the case of code group 0, thecorrelation device 41 correlates againstmidamble codes correlation device 41 correlates againstmidamble codes step 2processor 14. - The
correlation device 41 calculates 4×WS3 correlations. The periodic window allows thecorrelation device 41 to find the maximum correlation. The purpose of the multipath window is to adjust the PSCH position to include the maximum amount of multipath. This may be necessary if the strongest multipath component is not the first significant multipath component. - The correlation values output from the
correlation device 41, are forwarded to theaccumulation device 42 which is coupled to thecorrelation device 41 and thedecision device 43. Theaccumulation device 42 accumulates the correlation values over a predetermined number of frames N3. It should be noted that initial cell search does not know frame boundaries so the initial cell search system typically uses blocks of 38400 chips (2560 chips×15 slots) in lieu of frames. Theaccumulation device 42 forms the decision variables by adding the absolute value of the real and imaginary parts of the complex number that represents the correlation value. A decision variable is the magnitude measure of the corresponding correlation value. In order to have a more reliable decision, these decision variables can be accumulated for N3 iterations, where N3 is the maximum number of iterations for a reliable signal to noise ratio level. - The decision variables generated by the
accumulation device 42 are forwarded to thedecision device 43. Thedecision device 43, coupled to theaccumulation device 42, determines the maximum decision variable by simple sequential comparison. The maximum decision variable corresponds to the basic midamble used for the cell. The scrambling code number associated with the identified midamble is the scrambling code of the cell. The scrambling code is then utilized by the UE for broadcast channel processing. - The flow diagram for the initial cell search system is illustrated in
FIG. 7 . The UE receives the input signal over the common downlink channel (step 601). Thestep 1processor 12 detects the location of the PSC associated with the strongest base station (step 602). Thestep 1processor 12 forwards the PSC to the cancellation device 18 (step 603). Thecancellation device 18 then subtracts the PSC detected from thestep 1processor 12 from the input signal I (step 604) and forwards this modified signal to thestep 2 processor 14 (step 605). Using the modified input signal from thecancellation device 18 and the location of the PSC from thestep 1processor 12, thestep 2processor 14 retrieves the SSCs and determines toffset and the code group number associated with the strongest base station (step 606). The code group number is then forwarded to thestep 3 processor 16 (step 607) which retrieves the midambles and primary scrambling codes therefrom (step 608). These codes are then used by the UE to synchronize to the base station (step 609). - Since the second step of the initial cell search is the weakest, the cancellation of the PSC from the signal input to the
step 2processor 14 provides a cleaner signal and results in a better estimation of the SSCs time. This results in a more accurate slot offset and code group number determination. Ultimately, this procedure reduces the number of false detections by the UE. - A second embodiment is illustrated in
FIG. 8 . Similar to the system ofFIG. 1 , the system of this second embodiment utilizes acancellation device 18 2 to subtract the PSC and SSCs from the input signal I before processing by thestep 3processor 16.Step 2 does not receive a PSC removed input signal, instead the modified input signal to thestep 3processor 16 is able to more accurately detect the midamble and code group of the detected base station. - A third embodiment is illustrated in
FIG. 9 . This third embodiment utilizes thecancellation devices cell search system 10. Thecancellation device 18 1 removes the PSC from the detected location in the input signal prior to thestep 2processor 14. Thecancellation device 18 2 removes the SSCs prior to thestep 3processor 16.
Claims (8)
1. A user equipment (UE) configured to perform initial cell search in a wireless communication system having a plurality of base stations, each base station transmitting a common primary synchronization code (PSC) in a primary synchronization channel in conjunction with a base station specific secondary synchronization code (SSC) at a different time within a system frame, said UE receiving an input signal including the PSC and SSC from at least one of the base stations;
said UE comprising:
a step one processor for detecting PSCs within a selected time frame in said received input signal and determining a maximum PSC location, which corresponds to the maximum PSC value detected within the frame, and producing an output complex correlation value;
a cancellation device for subtracting the PSC value at the maximum PSC location within the frame to enhance detection of the SSC;
a step two processor, coupled to the step one processor and the cancellation device, configured to determine a scrambling code group number for the cell and a frame timing offset value for locating the frame boundary; and
a step three processor, coupled to the step two processor, configured to determine the scrambling code of the cell.
2. The UE of claim 1 wherein said cancellation device uses interference cancellation to remove said PSC from said input signal.
3. The UE of claim 1 wherein the step two processor comprises:
a correlator configured to correlate the input signal with a code sequence corresponding to the maximum PSC location.
4. The UE of claim 3 wherein the step two processor further comprises:
a device configured to correlate the input signal with N SSCs outputting a set of N complex correlation values t, where N is an integer greater than one.
5. The UE of claim 4 wherein the step two processor further comprises:
a phase estimator device configured to determine a phase estimate of the complex correlation value from the step one processor; and
a derotation device configured to derotate the set of N complex correlation values using the phase estimate.
6. The UE of claim 5 wherein the step two processor further comprises:
an accumulator configured to coherently add the derotated set of N correlation values at a predetermined period for a predetermined number of iterations, producing a set of decision variables; and
a decision device configured to select a maximum decision variable, from which the scrambling code group number for the cell and the frame timing offset value are determined.
7. The UE of claim 1 wherein the step three processor comprises:
a step three correlation device configured to produce step three correlation values that are the maximum correlation of the input signal correlated with midambles associated with the code group;
a step three accumulation device configured to accumulate the step three correlation values over a predetermined number of system frames producing step three decision variables; and
a step three decision device configured to determine the maximum step three decision variable from which the basic midamble for the cell and the scrambling code of the cell is determined.
8. The UE of claim 7 further comprising a second cancellation device coupled between the step two and step three processors configured to subtract the SSCs from the input signal to enhance detection of the code group number and midambles associated with the code group.
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Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20030202564A1 (en) * | 2002-04-25 | 2003-10-30 | Accton Technology Corporation | Method and apparatus for cell search for W-CDMA with effect of clock offset |
US20040258041A1 (en) * | 2003-06-17 | 2004-12-23 | Che-Li Lin | Cell search method suitable for initial cell search and target cell search |
US20050153721A1 (en) * | 2003-10-28 | 2005-07-14 | Lg Electronics Inc. | Frame synchronization for a mobile communication system |
US20080019350A1 (en) * | 2005-07-21 | 2008-01-24 | Onggosanusi Eko N | Downlink synchronization for a cellular ofdm communication system |
US20090122839A1 (en) * | 2007-10-11 | 2009-05-14 | Qualcomm Incorporated | Scrambling codes for secondary synchronization codes in wireless communication systems |
US20090147757A1 (en) * | 2005-08-22 | 2009-06-11 | Matsushita Electric Industrial Co., Ltd. | Base station device and mobile station device |
CN101490978A (en) * | 2006-04-20 | 2009-07-22 | 德克萨斯仪器股份有限公司 | Downlink synchronization channel and methods for cellular systems |
US20120120923A1 (en) * | 2010-11-12 | 2012-05-17 | Industrial Technology Research Institute | Methods and Systems for Multi-User Detection in CDMA-Based Common Channels and Computer Program Products Thereof |
US8493964B2 (en) | 2007-07-06 | 2013-07-23 | Lg Electronics Inc. | Method of performing cell search in wireless communication system |
US8520768B2 (en) | 2006-12-19 | 2013-08-27 | Lg Electronics Inc. | Sequence generating method for efficient detection and method for transmitting and receiving signals using the same |
CN106304318A (en) * | 2006-04-20 | 2017-01-04 | 德克萨斯仪器股份有限公司 | Downlink synchronization channel and the method for cellular system |
US11356818B2 (en) | 2019-11-11 | 2022-06-07 | Samsung Electronics Co., Ltd. | Electronic device and cell selection method thereof |
Families Citing this family (38)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6396819B1 (en) | 1998-03-21 | 2002-05-28 | Richard D. Fleeter | Low-cost satellite communication system |
US7227884B2 (en) | 2000-02-28 | 2007-06-05 | Aeroastro, Inc. | Spread-spectrum receiver with progressive fourier transform |
US7433391B2 (en) * | 2000-02-28 | 2008-10-07 | Aeroastro, Inc. | Spread-spectrum receiver with fast M-sequence transform |
US6894995B2 (en) * | 2001-06-22 | 2005-05-17 | Interdigital Technology Corporation | Apparatus and method for performing initial cell search in wireless communication systems |
JP3843040B2 (en) * | 2001-09-26 | 2006-11-08 | 松下電器産業株式会社 | Cell search method and communication terminal device |
KR100762602B1 (en) * | 2001-10-08 | 2007-10-01 | 삼성전자주식회사 | Apparatus and method for generating reference timing in cdma mobile communication system |
US7356098B2 (en) * | 2001-11-14 | 2008-04-08 | Ipwireless, Inc. | Method, communication system and communication unit for synchronisation for multi-rate communication |
US7065064B2 (en) * | 2001-12-20 | 2006-06-20 | Interdigital Technology Corporation | Cell search using peak quality factors |
US20030128787A1 (en) * | 2002-01-10 | 2003-07-10 | Daisuke Terasawa | Method and apparatus for mitigating interference between base stations in a wideband CDMA system |
US20040058650A1 (en) * | 2002-09-19 | 2004-03-25 | Torgny Palenius | Receivers and methods for searching for cells using recorded data |
US7738437B2 (en) * | 2003-01-21 | 2010-06-15 | Nortel Networks Limited | Physical layer structures and initial access schemes in an unsynchronized communication network |
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US6873833B2 (en) * | 2003-03-27 | 2005-03-29 | Interdigital Technology Corporation | Method and apparatus for estimating and controlling initial time slot gain in a wireless communication system |
WO2004093476A1 (en) * | 2003-04-16 | 2004-10-28 | Nec Corporation | Mobile communication system, base station, mobile station, and radio communication method used for them |
FR2857209B1 (en) * | 2003-07-03 | 2005-09-09 | Nec Technologies Uk Ltd | METHOD OF OPTIMIZING THE SEARCH OF CELLS BY A MOBILE TERMINAL |
JP4434202B2 (en) * | 2004-03-16 | 2010-03-17 | 日本電気株式会社 | Cell search method for wireless communication system |
AU2005201793A1 (en) * | 2004-05-21 | 2005-12-08 | Nec Australia Pty Ltd | Method of scheduling cell search operations |
US7917140B2 (en) * | 2004-12-06 | 2011-03-29 | Telefonaktiebolaget L M Ericsson (Publ) | Initial cell search in mobile communications systems |
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US8031745B2 (en) * | 2006-04-20 | 2011-10-04 | Texas Instruments Incorporated | Downlink synchronization channel and methods for cellular systems |
US7969964B2 (en) | 2006-07-25 | 2011-06-28 | Electronics & Telecommunications Research Institute | Cell search method, forward link frame transmission method, apparatus using the same and forward link frame structure |
US8223625B2 (en) * | 2006-08-23 | 2012-07-17 | Qualcomm, Incorporated | Acquisition in frequency division multiple access systems |
US8275080B2 (en) * | 2006-11-17 | 2012-09-25 | Comtech Mobile Datacom Corporation | Self-supporting simplex packets |
US8009661B2 (en) | 2007-01-31 | 2011-08-30 | Telefonaktiebolaget Lm Ericsson (Publ) | Cell searching system and method |
CN100556195C (en) * | 2007-04-29 | 2009-10-28 | 中兴通讯股份有限公司 | The detection of time division duplexing system circulation prefix types and cell initial search method |
US9119132B2 (en) * | 2007-10-10 | 2015-08-25 | Qualcomm Incorporated | Efficient system identification schemes for communication systems |
US8284749B2 (en) * | 2008-03-10 | 2012-10-09 | Comtech Mobile Datacom Corporation | Time slot synchronized, flexible bandwidth communication system |
KR20090116079A (en) * | 2008-05-06 | 2009-11-11 | 주식회사 팬택앤큐리텔 | Beam forming system and method for radio network controller |
US8548107B1 (en) | 2009-01-26 | 2013-10-01 | Comtech Mobile Datacom Corporation | Advanced multi-user detector |
US9106364B1 (en) | 2009-01-26 | 2015-08-11 | Comtech Mobile Datacom Corporation | Signal processing of a high capacity waveform |
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US8265625B2 (en) | 2009-08-20 | 2012-09-11 | Acer Incorporated | Systems and methods for network entry management |
US8675711B1 (en) | 2009-09-25 | 2014-03-18 | Comtech Mobile Datacom Corporation | System and methods for dynamic spread spectrum usage |
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GB2496383A (en) * | 2011-11-07 | 2013-05-15 | Nec Corp | Extension carriers having synchronisation signals with configurable locations |
US9510212B2 (en) | 2012-04-27 | 2016-11-29 | Qualcomm Incorporated | Signal designs for densely deployed network |
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US11363550B2 (en) * | 2018-11-28 | 2022-06-14 | Samsung Electronics Co., Ltd. | Wireless communication device for detecting synchronization signal and method of searching for synchronization signal by using the same |
Citations (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5930366A (en) * | 1997-08-29 | 1999-07-27 | Telefonaktiebolaget L M Ericsson | Synchronization to a base station and code acquisition within a spread spectrum communication system |
US6038250A (en) * | 1997-01-07 | 2000-03-14 | Yozan Inc. | Initial synchronization method and receiver for DS-CDMA inter base station asynchronous cellular system |
US6185244B1 (en) * | 1997-08-29 | 2001-02-06 | Telefonaktiebolaget Lm Ericsson | Cell searching in a CDMA communications system |
US6233466B1 (en) * | 1998-12-14 | 2001-05-15 | Metawave Communications Corporation | Downlink beamforming using beam sweeping and subscriber feedback |
US6246673B1 (en) * | 1999-02-26 | 2001-06-12 | Qualcomm Inc. | Method and system for handoff between an asynchronous CDMA base station and a synchronous CDMA base station |
US6363060B1 (en) * | 1999-06-30 | 2002-03-26 | Qualcomm Incorporated | Method and apparatus for fast WCDMA acquisition |
US6480558B1 (en) * | 1999-03-17 | 2002-11-12 | Ericsson Inc. | Synchronization and cell search methods and apparatus for wireless communications |
US6526039B1 (en) * | 1998-02-12 | 2003-02-25 | Telefonaktiebolaget Lm Ericsson | Method and system for facilitating timing of base stations in an asynchronous CDMA mobile communications system |
US6597729B1 (en) * | 2000-03-29 | 2003-07-22 | Texas Instruments Incorporated | Joint position and carrier frequency estimation method of initial frequency acquisition for a WCDMA mobile terminal |
US6665288B1 (en) * | 1999-11-08 | 2003-12-16 | Ericsson Inc. | Method and apparatus for reducing synchronization code interference in CDMA communications systems |
US6717930B1 (en) * | 2000-05-22 | 2004-04-06 | Interdigital Technology Corporation | Cell search procedure for time division duplex communication systems using code division multiple access |
US20040071119A1 (en) * | 1999-09-06 | 2004-04-15 | Yoshihiro Ishikawa | Control method of searching neighboring cells, mobile station, and mobile, communication system |
US6768768B2 (en) * | 2001-09-19 | 2004-07-27 | Qualcomm Incorporated | Method and apparatus for step two W-CDMA searching |
US6804311B1 (en) * | 1999-04-08 | 2004-10-12 | Texas Instruments Incorporated | Diversity detection for WCDMA |
US20050025087A1 (en) * | 1999-09-14 | 2005-02-03 | Nec Corporation | Cell search method in CDMA capable of carrying out a cell search processing at a high speed |
US6894995B2 (en) * | 2001-06-22 | 2005-05-17 | Interdigital Technology Corporation | Apparatus and method for performing initial cell search in wireless communication systems |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100369791B1 (en) | 1999-04-29 | 2003-01-29 | 삼성전자 주식회사 | Apparatus and method for synchronizing channel in w-cdma communication system |
-
2001
- 2001-10-31 US US09/998,885 patent/US6894995B2/en not_active Expired - Lifetime
-
2002
- 2002-04-15 ES ES02746306T patent/ES2287295T3/en not_active Expired - Lifetime
- 2002-04-15 IL IL15939002A patent/IL159390A0/en unknown
- 2002-04-15 KR KR1020037016571A patent/KR100703645B1/en active IP Right Grant
- 2002-04-15 CA CA002451242A patent/CA2451242C/en not_active Expired - Fee Related
- 2002-04-15 BR BR0211031-8A patent/BR0211031A/en not_active IP Right Cessation
- 2002-04-15 DE DE60220409T patent/DE60220409T2/en not_active Expired - Lifetime
- 2002-04-15 AT AT02746306T patent/ATE363777T1/en not_active IP Right Cessation
- 2002-04-15 CN CNA028124405A patent/CN1518808A/en active Pending
- 2002-04-15 MX MXPA03011879A patent/MXPA03011879A/en active IP Right Grant
- 2002-04-15 KR KR1020077011733A patent/KR20070065446A/en not_active Application Discontinuation
- 2002-04-15 WO PCT/US2002/011669 patent/WO2003001711A1/en active IP Right Grant
- 2002-04-15 JP JP2003507988A patent/JP3962016B2/en not_active Expired - Lifetime
- 2002-04-15 KR KR1020057015362A patent/KR20050098007A/en active IP Right Grant
- 2002-04-15 EP EP02746306A patent/EP1407566B1/en not_active Expired - Lifetime
- 2002-04-25 TW TW091108598A patent/TWI239779B/en not_active IP Right Cessation
- 2002-04-25 TW TW096102235A patent/TW200746660A/en unknown
- 2002-04-25 TW TW094129567A patent/TW200629783A/en unknown
- 2002-04-25 TW TW092127555A patent/TWI276316B/en not_active IP Right Cessation
-
2003
- 2003-12-19 NO NO20035741A patent/NO20035741L/en not_active Application Discontinuation
-
2005
- 2005-05-16 US US11/129,789 patent/US20050221848A1/en not_active Abandoned
Patent Citations (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6038250A (en) * | 1997-01-07 | 2000-03-14 | Yozan Inc. | Initial synchronization method and receiver for DS-CDMA inter base station asynchronous cellular system |
US6185244B1 (en) * | 1997-08-29 | 2001-02-06 | Telefonaktiebolaget Lm Ericsson | Cell searching in a CDMA communications system |
US5930366A (en) * | 1997-08-29 | 1999-07-27 | Telefonaktiebolaget L M Ericsson | Synchronization to a base station and code acquisition within a spread spectrum communication system |
US6526039B1 (en) * | 1998-02-12 | 2003-02-25 | Telefonaktiebolaget Lm Ericsson | Method and system for facilitating timing of base stations in an asynchronous CDMA mobile communications system |
US6233466B1 (en) * | 1998-12-14 | 2001-05-15 | Metawave Communications Corporation | Downlink beamforming using beam sweeping and subscriber feedback |
US6246673B1 (en) * | 1999-02-26 | 2001-06-12 | Qualcomm Inc. | Method and system for handoff between an asynchronous CDMA base station and a synchronous CDMA base station |
US6480558B1 (en) * | 1999-03-17 | 2002-11-12 | Ericsson Inc. | Synchronization and cell search methods and apparatus for wireless communications |
US6804311B1 (en) * | 1999-04-08 | 2004-10-12 | Texas Instruments Incorporated | Diversity detection for WCDMA |
US6363060B1 (en) * | 1999-06-30 | 2002-03-26 | Qualcomm Incorporated | Method and apparatus for fast WCDMA acquisition |
US20040071119A1 (en) * | 1999-09-06 | 2004-04-15 | Yoshihiro Ishikawa | Control method of searching neighboring cells, mobile station, and mobile, communication system |
US20050025087A1 (en) * | 1999-09-14 | 2005-02-03 | Nec Corporation | Cell search method in CDMA capable of carrying out a cell search processing at a high speed |
US6665288B1 (en) * | 1999-11-08 | 2003-12-16 | Ericsson Inc. | Method and apparatus for reducing synchronization code interference in CDMA communications systems |
US6597729B1 (en) * | 2000-03-29 | 2003-07-22 | Texas Instruments Incorporated | Joint position and carrier frequency estimation method of initial frequency acquisition for a WCDMA mobile terminal |
US6717930B1 (en) * | 2000-05-22 | 2004-04-06 | Interdigital Technology Corporation | Cell search procedure for time division duplex communication systems using code division multiple access |
US6894995B2 (en) * | 2001-06-22 | 2005-05-17 | Interdigital Technology Corporation | Apparatus and method for performing initial cell search in wireless communication systems |
US6768768B2 (en) * | 2001-09-19 | 2004-07-27 | Qualcomm Incorporated | Method and apparatus for step two W-CDMA searching |
Cited By (30)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7126981B2 (en) * | 2002-04-25 | 2006-10-24 | Accton Technology Corporation | Method and apparatus for cell search for W-CDMA with effect of clock offset |
US20030202564A1 (en) * | 2002-04-25 | 2003-10-30 | Accton Technology Corporation | Method and apparatus for cell search for W-CDMA with effect of clock offset |
US20040258041A1 (en) * | 2003-06-17 | 2004-12-23 | Che-Li Lin | Cell search method suitable for initial cell search and target cell search |
US7394801B2 (en) * | 2003-06-17 | 2008-07-01 | Qisda Corporation | Cell search method suitable for initial cell search and target cell search |
US20050153721A1 (en) * | 2003-10-28 | 2005-07-14 | Lg Electronics Inc. | Frame synchronization for a mobile communication system |
US7466684B2 (en) * | 2003-10-28 | 2008-12-16 | Lg Electronics Inc. | Frame synchronization for a mobile communication system |
US8134996B2 (en) * | 2005-07-21 | 2012-03-13 | Texas Instruments Incorporated | Downlink synchronization for a cellular OFDM communication system |
US20080019350A1 (en) * | 2005-07-21 | 2008-01-24 | Onggosanusi Eko N | Downlink synchronization for a cellular ofdm communication system |
US20090147757A1 (en) * | 2005-08-22 | 2009-06-11 | Matsushita Electric Industrial Co., Ltd. | Base station device and mobile station device |
CN101490978A (en) * | 2006-04-20 | 2009-07-22 | 德克萨斯仪器股份有限公司 | Downlink synchronization channel and methods for cellular systems |
CN106304318A (en) * | 2006-04-20 | 2017-01-04 | 德克萨斯仪器股份有限公司 | Downlink synchronization channel and the method for cellular system |
US10727969B2 (en) | 2006-12-19 | 2020-07-28 | Wild Guard Ltd. | Method and apparatus for transmitting or detecting a primary synchronization signal |
US10341037B2 (en) | 2006-12-19 | 2019-07-02 | Wild Guard Ltd. | Method and apparatus for transmitting or detecting a primary synchronization signal |
US10057003B2 (en) | 2006-12-19 | 2018-08-21 | Lg Electronics Inc. | Method and apparatus for transmitting or detecting a primary synchronization signal |
US11018794B2 (en) | 2006-12-19 | 2021-05-25 | Wild Guard Ltd. | Method and apparatus for transmitting or detecting a primary synchronization signal |
US9584244B2 (en) | 2006-12-19 | 2017-02-28 | Lg Electronics Inc. | Method and apparatus for transmitting or detecting a primary synchronization signal |
US8520768B2 (en) | 2006-12-19 | 2013-08-27 | Lg Electronics Inc. | Sequence generating method for efficient detection and method for transmitting and receiving signals using the same |
US8948294B2 (en) | 2006-12-19 | 2015-02-03 | Lg Electronics Inc. | Communication of synchronization signals between base station and terminal |
US8989327B2 (en) | 2006-12-19 | 2015-03-24 | Lg Electronics Inc. | Method and apparatus for transmitting or detecting a primary synchronization signal |
TWI404350B (en) * | 2007-07-06 | 2013-08-01 | Lg Electronics Inc | Method of performing cell search in wireless communication system |
US9113401B2 (en) | 2007-07-06 | 2015-08-18 | Lg Electronics Inc. | Method of performing cell search in wireless communication system |
US9736805B2 (en) | 2007-07-06 | 2017-08-15 | Lg Electronics Inc. | Method of performing cell search in wireless communication system |
US8493964B2 (en) | 2007-07-06 | 2013-07-23 | Lg Electronics Inc. | Method of performing cell search in wireless communication system |
US10219236B2 (en) | 2007-07-06 | 2019-02-26 | Lg Electronics Inc. | Method of performing cell search in wireless communication system |
US10638441B2 (en) | 2007-07-06 | 2020-04-28 | Lg Electronics Inc. | Method of performing cell search in wireless communication system |
US8503547B2 (en) * | 2007-10-11 | 2013-08-06 | Qualcomm Incorporated | Scrambling codes for secondary synchronization codes in wireless communication systems |
US20090122839A1 (en) * | 2007-10-11 | 2009-05-14 | Qualcomm Incorporated | Scrambling codes for secondary synchronization codes in wireless communication systems |
US8472411B2 (en) * | 2010-11-12 | 2013-06-25 | Industrial Technology Research Institute | Methods and systems for multi-user detection in CDMA-based common channels and computer program products thereof |
US20120120923A1 (en) * | 2010-11-12 | 2012-05-17 | Industrial Technology Research Institute | Methods and Systems for Multi-User Detection in CDMA-Based Common Channels and Computer Program Products Thereof |
US11356818B2 (en) | 2019-11-11 | 2022-06-07 | Samsung Electronics Co., Ltd. | Electronic device and cell selection method thereof |
Also Published As
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KR20050098007A (en) | 2005-10-10 |
JP2004533784A (en) | 2004-11-04 |
BR0211031A (en) | 2004-06-22 |
TW200629783A (en) | 2006-08-16 |
TW200746660A (en) | 2007-12-16 |
CN1518808A (en) | 2004-08-04 |
ES2287295T3 (en) | 2007-12-16 |
EP1407566A4 (en) | 2004-09-22 |
KR20040007737A (en) | 2004-01-24 |
NO20035741L (en) | 2004-02-23 |
EP1407566A1 (en) | 2004-04-14 |
EP1407566B1 (en) | 2007-05-30 |
US6894995B2 (en) | 2005-05-17 |
US20030031162A1 (en) | 2003-02-13 |
MXPA03011879A (en) | 2004-03-26 |
ATE363777T1 (en) | 2007-06-15 |
CA2451242C (en) | 2008-04-08 |
DE60220409D1 (en) | 2007-07-12 |
WO2003001711A1 (en) | 2003-01-03 |
KR100703645B1 (en) | 2007-04-05 |
JP3962016B2 (en) | 2007-08-22 |
NO20035741D0 (en) | 2003-12-19 |
IL159390A0 (en) | 2004-06-01 |
CA2451242A1 (en) | 2003-01-03 |
DE60220409T2 (en) | 2008-01-24 |
TWI239779B (en) | 2005-09-11 |
TW200421763A (en) | 2004-10-16 |
TWI276316B (en) | 2007-03-11 |
KR20070065446A (en) | 2007-06-22 |
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