USRE49665E1 - Generating downlink frame and searching for cell - Google Patents
Generating downlink frame and searching for cell Download PDFInfo
- Publication number
- USRE49665E1 USRE49665E1 US16/813,737 US202016813737A USRE49665E US RE49665 E1 USRE49665 E1 US RE49665E1 US 202016813737 A US202016813737 A US 202016813737A US RE49665 E USRE49665 E US RE49665E
- Authority
- US
- United States
- Prior art keywords
- sequence
- synchronization signal
- secondary synchronization
- short
- scrambling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active, expires
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J11/00—Orthogonal multiplex systems, e.g. using WALSH codes
- H04J11/0069—Cell search, i.e. determining cell identity [cell-ID]
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J11/00—Orthogonal multiplex systems, e.g. using WALSH codes
- H04J11/0069—Cell search, i.e. determining cell identity [cell-ID]
- H04J11/0076—Acquisition of secondary synchronisation channel, e.g. detection of cell-ID group
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
- H04L25/03828—Arrangements for spectral shaping; Arrangements for providing signals with specified spectral properties
- H04L25/03866—Arrangements for spectral shaping; Arrangements for providing signals with specified spectral properties using scrambling
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
- H04L27/261—Details of reference signals
- H04L27/2613—Structure of the reference signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W48/00—Access restriction; Network selection; Access point selection
- H04W48/16—Discovering, processing access restriction or access information
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2656—Frame synchronisation, e.g. packet synchronisation, time division duplex [TDD] switching point detection or subframe synchronisation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2657—Carrier synchronisation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2662—Symbol synchronisation
Definitions
- the present invention relates to a downlink frame generation method and a cell search method, and particularly relates to a method for generating a downlink frame and a method for searching for a cell by using the downlink frame in an orthogonal frequency division multiplexing (OFDM)-based cellular system.
- OFDM orthogonal frequency division multiplexing
- the code hopping method is applied to a pilot channel in order to acquire cell synchronization and appropriate cell identification information.
- the code hopping method introduces a code hopping technique to the pilot channel so that a terminal may easily search for the cell without an additional synchronization channel.
- the usage of the time domain may waste resources with respect to capacity, and hence it is difficult to apply the code hopping method to the pilot channel time domain of the OFDM-based system. Therefore, it is desirable in the OFDM case to search for cells by efficiently using the received signals in the time domain and the frequency domain.
- a conventional technique for searching for cells in the OFDM system includes divide a frame into four time blocks and allocating synchronization information and cell information.
- the technique proposes two frame structures.
- the first frame structure allocates synchronization recognition information, cell group recognition information, appropriate cell recognition information, and synchronization recognition information to four time blocks.
- the second frame structure allocates synchronization recognition information and appropriate cell recognition information to the first time block and the third time block, and synchronization recognition information and cell group recognition information to the second time block and the fourth time block.
- the cell search process is complicated and it is difficult to search for the cells quickly since it is required to acquire synchronization and simultaneously correlate appropriate cell recognition information or cell group recognition information so as to acquire frame synchronization.
- Another method for searching for cells using an additional preamble to acquire synchronization and search for the cells has been proposed, but it is inapplicable to a system having no preamble.
- the terminal since the preamble is disposed at the front part of the frame, the terminal must stand by for the next frame when attempting to acquire synchronization at a time position other than the first time position of the frame.
- the terminal when the terminal performs a handover among the GSM mode, the WCDMA mode, and the 3GPP LTE mode, it must acquire the initial symbol synchronization within 5 msec, but the initial symbol synchronization may not be acquired within 5 msec since the synchronization can be acquired for each frame.
- the present invention has been made in an effort to provide a downlink frame generating method for averaging interference between sectors, and an efficient cell searching method by receiving the downlink frame.
- An exemplary embodiment of the present invention provides a method for generating a downlink frame including a first synchronization signal and a second synchronization signal, including: generating a first short sequence and a second short sequence indicating cell group information; generating a first scrambling sequence determined by the first synchronization signal; generating a second scrambling sequence determined by the first short sequence; scrambling the first short sequence with the first scrambling sequence, and scrambling the second short sequence with at least second scrambling sequence; and mapping a second synchronization signal including the scrambled first short sequence and the scrambled second short sequence in the frequency domain.
- Another embodiment of the present invention provides a device for generating a downlink frame including a first synchronization signal and a second synchronization signal, including: a sequence generator for generating a first short sequence and a second short sequence indicating cell group information, a first scrambling sequence determined by the first synchronization signal, and a second scrambling sequence determined by the first short sequence; and a synchronization signal generator for scrambling the first short sequence with the first scrambling sequence, scrambling the second short sequence with at least the second scrambling sequence, and generating a second synchronization signal including the scrambled first short sequence and the scrambled second short sequence.
- Yet another embodiment of the present invention provides a recording medium for recording a program for performing a method of generating a downlink frame including a first synchronization signal and a second synchronization signal, wherein the method includes: generating a first short sequence and a second short sequence indicating cell group information; generating a first scrambling sequence determined by the first synchronization signal; generating a second scrambling sequence determined by the first short sequence; scrambling the first short sequence with the first scrambling sequence, and scrambling the second short sequence with at least the second scrambling sequence; and mapping a second synchronization signal including the scrambled first short sequence and the scrambled second short sequence in the frequency domain.
- cell search performance is improved by scrambling a short sequence with a scrambling sequence and reducing interference between sectors.
- FIG. 1 shows a downlink frame of an OFDM system according to an exemplary embodiment of the present invention.
- FIG. 2 shows a synchronization channel configuration diagram indicating a secondary synchronization channel when two sequences are mapped on the frequency domain in a centralized manner.
- FIG. 3 shows a synchronization channel configuration diagram indicating a secondary synchronization channel when two sequences are mapped on the frequency domain in a distributive manner.
- FIG. 4 shows a block diagram of a downlink frame generating device according to an exemplary embodiment of the present invention.
- FIG. 5 shows a flowchart of a downlink frame generating method according to an exemplary embodiment of the present invention.
- FIG. 6 shows a first method for generating a secondary synchronization signal according to an exemplary embodiment of the present invention.
- FIG. 7 shows a second method for generating a secondary synchronization signal according to an exemplary embodiment of the present invention.
- FIG. 8 shows a block diagram of a cell searching device according to an exemplary embodiment of the present invention.
- FIG. 9 shows a flowchart of a cell searching method according to a first exemplary embodiment of the present invention.
- FIG. 10 shows a flowchart of a cell searching method according to a second exemplary embodiment of the present invention.
- a unit, a device, and a module in the present specification represent a unit for processing a predetermined function or operation, which can be realized by hardware, software, or combination of hardware and software.
- a downlink frame and a synchronization channel of an OFDM system will now be described with reference to FIG. 1 to FIG. 3 .
- FIG. 1 shows a downlink frame of an OFDM system according to an exemplary embodiment of the present invention.
- the horizontal axis represents the time axis
- the vertical axis represents the frequency axis or a subcarrier axis.
- a downlink frame 110 has a time interval of 10 msec and includes ten subframes 120 .
- One subframe 120 has a time interval of 1 msec and includes two slots 130 , and one slot 130 includes six or seven OFDM symbols.
- one slot includes six symbols, it has a cyclic prefix length that is greater than the case in which one slot includes seven symbols.
- one downlink frame 110 includes one synchronization interval 140 at the slot 0 and the slot 10 respectively, to thus include two synchronization intervals 140 .
- the embodiment of the present invention is not restricted to this. That is, one downlink frame 110 may include a synchronization interval at a random slot, and may include one or at least three synchronization intervals. Also, since the length of the cyclic prefix may be different for each slot, it is desirable to provide the synchronization interval to the last position of the slot.
- Each slot includes a pilot interval.
- a synchronization interval according to an exemplary embodiment of the present invention includes a primary synchronization channel and a secondary synchronization channel, and the primary synchronization channel and the secondary synchronization channel are disposed adjacently with respect to time. As shown in FIG. 1 , a primary synchronization channel is provided to the last position of the slot, and a secondary synchronization channel is provided before the primary synchronization channel.
- the primary synchronization channel includes information for identifying symbol synchronization and frequency synchronization, and some cell ID (identification) information
- the secondary synchronization channel includes information for identifying other cell ID information and frame synchronization.
- the mobile station identifies the cell ID through combination of cell ID information of the primary and secondary synchronization channels.
- the 510 cell IDs into 170 groups by using the 170 secondary synchronization signals allocated to the secondary synchronization channel, and express the cell ID information in the cell groups by using the three primary synchronization signals allocated to the primary synchronization channel.
- the secondary synchronization channel includes information for identifying frame synchronization as well as cell ID information, two secondary synchronization channels included in one frame are different.
- FIG. 2 shows a synchronization channel configuration diagram indicating a secondary synchronization channel when two sequences are mapped on the frequency domain in a centralized manner
- FIG. 3 shows a synchronization channel configuration diagram indicating a secondary synchronization channel when two sequences are mapped on the frequency domain in a distributive manner.
- a secondary synchronization signal inserted into a secondary synchronization channel is configured by a combination of two sequences. Cell group information and frame synchronization information are mapped on the two sequences.
- the length of sequence is half the number of subcarriers allocated to the secondary synchronization channel. That is, the number of elements of the sequence that can be generated is as many as half the number of subcarriers allocated to the secondary synchronization channel. For example, when the number of subcarriers allocated to the secondary synchronization channel is 62, the length of the sequence is 31, and up to 31 elements of the sequence can be generated.
- FIG. 4 shows a block diagram of a downlink frame generating device according to an exemplary embodiment of the present invention.
- the downlink frame generating device includes a sequence generator 410 , a synchronization signal generator 420 , a frequency mapper 430 , and an OFDM transmitter 440 .
- the sequence generator 410 generates a time and frequency synchronization acquiring sequence, a cell identifying sequence, a plurality of short sequences, and an adjacent cell interference reducing scrambling sequence, and transmits them to the synchronization signal generator 420 .
- the synchronization signal generator 420 generates a primary synchronization signal, a secondary synchronization signal, and a pilot pattern by using the sequences transmitted by the sequence generator 410 .
- the synchronization signal generator 420 generates a primary synchronization signal by using a time and frequency synchronization acquiring sequence and a cell identifying sequence.
- the synchronization signal generator 420 generates a secondary synchronization signal by using a plurality of short sequences and an adjacent cell interference reducing scrambling sequence.
- the synchronization signal generator 420 generates a pilot pattern of a downlink signal by allocating a proper scrambling sequence that is allocated for each cell to the pilot channel so as to encode a common pilot symbol and a data symbol of the cellular system.
- the frequency mapper 430 maps the primary synchronization signal, the secondary synchronization signal, and the pilot pattern generated by the synchronization signal generator 420 , and frame control information and transmission traffic data provided from the outside in the time and frequency domains to generate a downlink frame.
- the OFDM transmitter 440 receives the downlink frame from the frequency mapper 430 and transmits it through a transmitting antenna.
- FIG. 5 shows a flowchart of a downlink frame generating method according to an exemplary embodiment of the present invention.
- the sequence generator 410 generates a plurality of short sequences and a plurality of adjacent cell interference reducing scrambling sequences and transmits them to the synchronization signal generator 420 (S 510 ).
- the synchronization signal generator 420 generates a secondary synchronization signal by using the short sequences and the adjacent cell interference reducing scrambling sequences transmitted by the sequence generator 410 (S 520 ).
- the exemplary embodiment of the present invention will exemplify the frame including two secondary synchronization channels, but is not limited thereto.
- FIG. 6 shows a first method for generating a secondary synchronization signal according to an exemplary embodiment of the present invention
- FIG. 7 shows a second method for generating a secondary synchronization signal according to an exemplary embodiment of the present invention.
- a short sequence (wn) is a binary sequence (binary code) indicating cell group information. That is, the short sequence (wn) is a binary sequence allocated for the cell group number and the frame synchronization, and its length is half the number of subcarriers allocated to the secondary synchronization channel.
- the exemplary embodiment of the present invention describes the case in which the number of subcarriers allocated to the secondary synchronization channel symbol is 62, but is not limited thereto. Therefore, the length of the short sequence according to the exemplary embodiment of the present invention is 31.
- the first short sequence (w0) is a sequence allocated to the even subcarrier of the first (slot 0 ) secondary synchronization channel and is expressed in Equation 1.
- w0 [w0(0),w0(1), . . . ,w0(k), . . . ,w0(30)] [Equation 1]
- k represents an index of the even subcarrier used for the synchronization channel.
- the second short sequence (w1) is a sequence allocated to the odd subcarrier of the first (slot 0 ) secondary synchronization channel and is expressed in Equation 2.
- w1 [w1(0),w1(1), . . . ,w1(m), . . . ,w1(30)] [Equation 2]
- m represents an index of the odd subcarrier used for the synchronization channel.
- the third short sequence (w2) is a sequence allocated to the even subcarrier of the second (slot 10 ) secondary synchronization channel and is expressed in Equation 3.
- w2 [w2(0),w2(1), . . . ,w2(k), . . . ,w2(30)] [Equation 3]
- the fourth short sequence (w3) is a sequence allocated to the odd subcarrier of the second (slot 10 ) secondary synchronization channel and is expressed in Equation 4.
- w3 [w3(0),w3(1), . . . ,w3(m), . . . ,w3(30)] [Equation 4]
- the short sequences of the second secondary synchronization channel can be allocated by using the short sequences allocated to the first synchronization channel, and a terminal only needs to memorize the 170 short sequences allocated to the first secondary synchronization channel and thereby reduce the complexity.
- the first method for generating the secondary synchronization signal is to allocate the first short sequence to every even subcarrier of the first secondary synchronization channel and the second short sequence to every odd subcarrier of the first secondary synchronization channel as shown in FIG. 6 .
- the first method is then to allocate the third short sequence to every even subcarrier of the second secondary synchronization channel and the fourth short sequence to every odd subcarrier of the second secondary synchronization channel.
- the number of the secondary synchronization signals becomes 961 which is sufficiently greater than the required number of 170 or 340.
- the second method for generating the secondary synchronization signal is to allocate the first sequence determined by Equation 5 to every even subcarrier of the first (slot 0 ) secondary synchronization channel, and the second sequence determined by Equation 6 to every odd subcarrier of the first (slot 0 ) secondary synchronization channel, as shown in FIG. 7 .
- the second method also includes allocating the third sequence determined by Equation 7 to every even subcarrier of the second (slot 10 ) secondary synchronization channel, and the fourth sequence determined by Equation 8 to every odd subcarrier of the second (slot 10 ) secondary synchronization channel.
- respective elements of the first sequence c 0 according to the second method for generating the secondary synchronization signal are products of respective elements of the first short sequence w0 and respective corresponding elements of P j,1 .
- c 0 [w0(0)P j,1 (0),w0(1)P j,1 (1), . . . ,w0(k)P j,1 (k), . . . ,w0(30)P j,1 (30)] [Equation 5]
- k is an index of the even subcarrier used for the synchronization channel.
- the length of the short sequence is 31 in the exemplary embodiment of the present invention, there are 31 short sequences. Therefore, the 0 to 7 short sequences are set to belong to the group 0, the 8 to 15 short sequences are set to belong to the group 1, the 16 to 23 short sequences are set to belong to the group 2, and the 24 to 30 short sequences are set to belong to the group 3, a scrambling code is mapped on each group, and the scrambling code mapped on the group to which the first short sequence belongs is determined to be S w0 .
- the short sequence having the residual 0 is set to belong to the group 0
- the short sequence having the residual 1 is set to belong to the group 1
- the short sequence having the residual 2 is set to belong to the group 2
- the short sequence having the residual 3 is set to belong to the group 3
- the short sequence having the residual 4 is set to belong to the group 4
- the short sequence having the residual 5 is set to belong to the group 5
- the short sequence having the residual 6 is set to belong to the group 6
- the short sequence having the residual 7 is set to belong to the group 7, a scrambling code is mapped on each group, and the scrambling code mapped on the group to which the first short sequence belongs is determined to be S w0 .
- the respective elements of the second sequence c 1 according to the second method for generating the secondary synchronization signal are products of the respective elements of the second short sequence w1 and the corresponding respective elements of S w0 . c 1 [w1(0)S w0 (0),w1(1)S w0 (1), . . . ,w1(m)S w0 (m), . . . ,w1(30)S w0 (30)] [Equation 6]
- m is an index of the odd subcarrier used for the synchronization channel.
- the respective elements of the third sequence c 2 according to the second method for generating the secondary synchronization signal are products of the respective elements of the third short sequence w2 and the corresponding respective elements of P j,2 .
- c 2 [w2(0)P j,2 (0),w2(1)P j,2 (1), . . . ,w2(k)P j,2 (k), . . . ,w2(30)P j,2 (30)] [Equation 7]
- k is an index of the even subcarrier used for the synchronization channel.
- the length of the short sequence according to the exemplary embodiment of the present invention is 31, there are 31 short sequences. Therefore, the 0 to 7 short sequences are set to belong to the group 0, the 8 to 15 short sequences are set to belong to the group 1, the 16 to 23 short sequences are set to belong to the group 2, the 24 to 30 short sequences are set to belong to the group 3, a scrambling code is mapped on each group, and the scrambling code mapped on the group to which the third short sequence belongs is determine to be S w2 .
- the short sequence with the residual 0 is set to belong to the group 0
- the short sequence with the residual 1 is set to belong to the group 1
- the short sequence with the residual 2 is set to belong to the group 2
- the short sequence with the residual 3 is set to belong to the group 3
- the short sequence with the residual 4 is set to belong to the group 4
- the short sequence with the residual 5 is set to belong to the group 5
- the short sequence with the residual 6 is set to belong to the group 6
- the short sequence with the residual 7 is set to belong to the group 7, a scrambling code is mapped on each group, and the scrambling code mapped on the group to which the third short sequence belongs is determined to be S w2 .
- the respective elements of the fourth sequence c 3 according to the second method for generating the secondary synchronization signal are the products of the respective elements of the fourth short sequence and the corresponding respective elements of S w2 .
- c 3 [w3(0)S w2 0,w3(1)S w2 (1), . . . ,w3(m)S w2 (m), . . . ,w3(30)S w2 (30)] [Equation 8]
- m is an index of the odd subcarrier used for the synchronization channel.
- the frequency mapper 430 maps the secondary synchronization signal and the transmission traffic data generated by the synchronization signal generator 420 in the time and frequency domains to generate a frame of the downlink signal (S 530 ).
- the OFDM transmitter 440 receives the frame of the downlink signal and transmits it through the transmitting antenna (S 540 ).
- a method for a terminal to search for the cell by using a downlink signal according to an exemplary embodiment of the present invention will now be described with reference to FIG. 8 to FIG. 10 .
- FIG. 8 shows a block diagram of a cell searching device according to an exemplary embodiment of the present invention
- FIG. 9 shows a flowchart of a cell searching method according to a first exemplary embodiment of the present invention
- FIG. 10 shows a flowchart of a cell searching method according to a second exemplary embodiment of the present invention.
- the cell searching device includes a receiver 810 , a symbol synchronization estimation and frequency offset compensator 820 , a Fourier transformer 830 , and a cell ID estimator 840 .
- a cell searching method according to a first exemplary embodiment of the present invention will now be described with reference to FIG. 9 .
- the receiver 810 receives the frame from the base station, and the symbol synchronization estimation and frequency offset compensator 820 filters the received signal by the bandwidth allocated to the synchronization channel, correlates the filtered received signal and a plurality of predetermined primary synchronization signals to acquire symbol synchronization, and estimates frequency synchronization to compensate for a frequency offset (S 910 ).
- the symbol synchronization estimation and frequency offset compensator 820 correlates the filtered received signal and a plurality of predetermined primary synchronization signals, estimates the time having the greatest correlation value to be symbol synchronization, and transmits the number of the primary synchronization signal having the greatest correlation value to the cell ID estimator 840 . In this instance, frequency offset is compensated in the frequency domain after Fourier transform.
- the Fourier transformer 830 performs a Fourier transform process on the received signal with reference to the symbol synchronization estimated by the symbol synchronization estimation and frequency offset compensator 820 (S 920 ).
- the cell ID estimator 840 correlates the Fourier transformed received signal and a plurality of predetermined secondary synchronization signals to estimate a cell ID group and frame synchronization (S 930 ).
- the cell ID estimator 840 correlates the Fourier transformed received signal and a plurality of secondary synchronization signals that are generated by applying P j,1 and P j,2 that are determined by the primary synchronization signal corresponding to the number of the primary synchronization signal transmitted by the symbol synchronization estimation and frequency offset compensator 820 to Equation 5 to Equation 8, and estimates the frame synchronization and the cell ID group by using the secondary synchronization signal having the greatest correlation value.
- the synchronization channel symbol in one frame is provided within one slot or one OFDM symbol, there is no need of additionally acquiring frame synchronization since the symbol synchronization becomes the frame synchronization.
- the cell ID estimator 840 estimates the cell ID by using the number of the primary synchronization signal transmitted by the symbol synchronization estimation and frequency offset compensator 820 and the estimated cell ID group (S 940 ). In this instance, the cell ID estimator 840 estimates the cell ID by referring to the mapping relation of the predetermined primary synchronization signal number, cell ID group, and cell ID.
- the estimated cell ID information can be checked by using scrambling sequence information included in the pilot symbol interval.
- a cell searching method according to a second exemplary embodiment of the present invention will now be described with reference to FIG. 10 .
- the receiver 810 receives the frame from the base station, and the symbol synchronization estimation and frequency offset compensator 820 filters the received signal by the bandwidth allocated to the synchronization channel, correlates the filtered received signal and a plurality of predetermined primary synchronization signals to acquire symbol synchronization, and estimates frequency synchronization to compensate the frequency offset (S 710 ).
- the symbol synchronization estimation and frequency offset compensator 820 correlates the filtered received signal and a plurality of predetermined primary synchronization signals to estimate the time having the greatest correlation value to be symbol synchronization, and transmits a plurality of correlation values that are generated by correlating the primary synchronization signals and the filtered received signal to the cell ID estimator 840 .
- the frequency offset can be compensated in the frequency domain after Fourier transform.
- the Fourier transformer 830 performs a Fourier transform process on the received signal with reference to the symbol synchronization estimated by the symbol synchronization estimation and frequency offset compensator 820 (S 720 ).
- the cell ID estimator 840 estimates the cell ID by using a plurality of correlation values transmitted by the symbol synchronization estimation and frequency offset compensator 820 , the Fourier transformed received signal, and correlation values of a plurality of predetermined secondary synchronization signals (S 730 ).
- the cell ID estimator 840 correlates the Fourier transformed received signal and a plurality of secondary synchronization signals that are generated by applying P j,1 and P j,2 that are determined according to the corresponding primary synchronization signals to Equation 5 to Equation 8, and finds the secondary synchronization signal having the greatest correlation value, regarding a plurality of respective primary synchronization signals.
- the cell ID estimator 840 combines the correlation value of the corresponding primary synchronization signal transmitted by the symbol synchronization estimation and frequency offset compensator 820 and the correlation value of the secondary synchronization signal having the greatest correlation value with the Fourier transformed received signal from among a plurality of secondary synchronization signals that are generated by applying P j,1 and P j,2 that are determined by the corresponding primary synchronization signal to Equation 5 to Equation 8, regarding a plurality of respective primary synchronization signals.
- the cell ID estimator 840 estimates the frame synchronization and the cell ID group by using the secondary synchronization signal having the greatest value generated by combining the correlation value of the primary synchronization signal and the correlation value of the secondary synchronization signal.
- the cell ID estimator 840 estimates the cell ID by using the estimated cell ID group and the primary synchronization signal having the greatest value generated by combining the correlation value of the primary synchronization signal and the correlation value of the secondary synchronization signal. In this instance, the cell ID estimator 840 estimates the cell ID by referring to the mapping relation of the predetermined primary synchronization signal number, cell ID group, and cell ID.
- the above-described embodiments can be realized through a program for realizing functions corresponding to the configuration of the embodiments or a recording medium for recording the program in addition to through the above-described device and/or method, which is easily realized by a person skilled in the art.
- the recording medium may include, but not limited to, a read only memory (ROM), a random access memory (RAM), an electrically programmable read-only memory (EEPROM), a flash memory, etc.
- the program may be executed by one or more hardware processors to achieve the function corresponding to the configuration of the exemplary embodiment.
- the hardware processor may include, but not limited to, a DSP (digital signal processor), a CPU (central processing unit), an ASIC (application specific integrated circuit), a programmable logic element, such as an FPGA (field programmable gate array), etc.
Abstract
The present invention relates to a method for generating a downlink frame including generating a first short sequence and a second short sequence indicating cell group information, generating a first scrambling sequence determined by the first synchronization signal, generating a second scrambling sequence determined by the first short sequence, scrambling the first short sequence with the first scrambling sequence, scrambling the second short sequence with at least the second scrambling sequence, and mapping a second synchronization signal including the scrambled first short sequence and the scrambled second short sequence in the frequency domain.
Description
Multiple reissue applications have been filed for the reissue of U.S. Pat. No. 8,982,911. The reissue applications are application Ser. No. 15/461,510, filed Mar. 17, 2017 and issued as U.S. Pat. No. RE47,910, on Mar. 17, 2020, and the present continuation reissue application, filed Mar. 10, 2020.
This applicationThis continuation reissue application is a continuation reissue application of U.S. application Ser. No. 15/461,510, filed Mar. 17, 2017 and issued as U.S. Pat. No. RE47,910, on Mar. 17, 2020, which is a reissue application of U.S. Pat. No. 8,982,911 issued Mar. 17, 2015, which is issued from U.S. application Ser. No. 13/672,041, filed Nov. 8, 2012, which is a continuation of U.S. patent application Ser. No. 12/487,847, filed on Jun. 19, 2009, which is a continuation of PCT application No. PCT/KR2008/004093, filed on Jul. 11, 2008, which claims priority to, and the benefit of, Korean Patent Application No. 10-2007-0070086 filed on Jul. 12, 2007, Korean Patent Application No. 10-2007-0082678 filed on Aug. 17, 2007, Korean Patent Application No. 10-2007-0083916 filed on Aug. 21, 2007, Korean Patent Application No. 10-2008-0061429 filed on Jun. 27, 2008. The contents of the aforementioned applications are incorporated herein by reference.
(a) Field
The present invention relates to a downlink frame generation method and a cell search method, and particularly relates to a method for generating a downlink frame and a method for searching for a cell by using the downlink frame in an orthogonal frequency division multiplexing (OFDM)-based cellular system.
(b) Description of the Related Art
In a direct sequence code division multiple access (DS-CDMA) system, the code hopping method is applied to a pilot channel in order to acquire cell synchronization and appropriate cell identification information. The code hopping method introduces a code hopping technique to the pilot channel so that a terminal may easily search for the cell without an additional synchronization channel. However, since the number of channels that are distinguishable by the frequency domain in the symbol interval is much greater than the number of channels that are distinguishable by the CDMA spread in one time domain symbol interval in the OFDM system, the usage of the time domain may waste resources with respect to capacity, and hence it is difficult to apply the code hopping method to the pilot channel time domain of the OFDM-based system. Therefore, it is desirable in the OFDM case to search for cells by efficiently using the received signals in the time domain and the frequency domain.
A conventional technique for searching for cells in the OFDM system includes divide a frame into four time blocks and allocating synchronization information and cell information. The technique proposes two frame structures. The first frame structure allocates synchronization recognition information, cell group recognition information, appropriate cell recognition information, and synchronization recognition information to four time blocks. The second frame structure allocates synchronization recognition information and appropriate cell recognition information to the first time block and the third time block, and synchronization recognition information and cell group recognition information to the second time block and the fourth time block.
In the case of following the first scheme, since symbol synchronization is acquired in the first time block, it is impossible to acquire fast synchronization within the standard of 5 ms when a terminal is turned on or in the case of a handover between heterogeneous networks. Also, it is difficult to acquire a diversity gain through accumulation of synchronization recognition information for fast synchronization acquisition.
In the case of following the second scheme, the cell search process is complicated and it is difficult to search for the cells quickly since it is required to acquire synchronization and simultaneously correlate appropriate cell recognition information or cell group recognition information so as to acquire frame synchronization.
Another method for searching for cells using an additional preamble to acquire synchronization and search for the cells has been proposed, but it is inapplicable to a system having no preamble. Further, since the preamble is disposed at the front part of the frame, the terminal must stand by for the next frame when attempting to acquire synchronization at a time position other than the first time position of the frame. Particularly, when the terminal performs a handover among the GSM mode, the WCDMA mode, and the 3GPP LTE mode, it must acquire the initial symbol synchronization within 5 msec, but the initial symbol synchronization may not be acquired within 5 msec since the synchronization can be acquired for each frame.
The present invention has been made in an effort to provide a downlink frame generating method for averaging interference between sectors, and an efficient cell searching method by receiving the downlink frame.
An exemplary embodiment of the present invention provides a method for generating a downlink frame including a first synchronization signal and a second synchronization signal, including: generating a first short sequence and a second short sequence indicating cell group information; generating a first scrambling sequence determined by the first synchronization signal; generating a second scrambling sequence determined by the first short sequence; scrambling the first short sequence with the first scrambling sequence, and scrambling the second short sequence with at least second scrambling sequence; and mapping a second synchronization signal including the scrambled first short sequence and the scrambled second short sequence in the frequency domain.
Another embodiment of the present invention provides a device for generating a downlink frame including a first synchronization signal and a second synchronization signal, including: a sequence generator for generating a first short sequence and a second short sequence indicating cell group information, a first scrambling sequence determined by the first synchronization signal, and a second scrambling sequence determined by the first short sequence; and a synchronization signal generator for scrambling the first short sequence with the first scrambling sequence, scrambling the second short sequence with at least the second scrambling sequence, and generating a second synchronization signal including the scrambled first short sequence and the scrambled second short sequence.
Yet another embodiment of the present invention provides a recording medium for recording a program for performing a method of generating a downlink frame including a first synchronization signal and a second synchronization signal, wherein the method includes: generating a first short sequence and a second short sequence indicating cell group information; generating a first scrambling sequence determined by the first synchronization signal; generating a second scrambling sequence determined by the first short sequence; scrambling the first short sequence with the first scrambling sequence, and scrambling the second short sequence with at least the second scrambling sequence; and mapping a second synchronization signal including the scrambled first short sequence and the scrambled second short sequence in the frequency domain.
According to the present invention, cell search performance is improved by scrambling a short sequence with a scrambling sequence and reducing interference between sectors.
In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. For clarification of drawings in the present invention, parts that are not related to the description will be omitted, and the same part will have the same reference numeral throughout the specification.
Throughout the specification, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. Also, the terms of a unit, a device, and a module in the present specification represent a unit for processing a predetermined function or operation, which can be realized by hardware, software, or combination of hardware and software.
A downlink frame and a synchronization channel of an OFDM system according to an exemplary embodiment of the present invention will now be described with reference to FIG. 1 to FIG. 3 .
As shown in FIG. 1 , a downlink frame 110 according to an exemplary embodiment of the present invention has a time interval of 10 msec and includes ten subframes 120. One subframe 120 has a time interval of 1 msec and includes two slots 130, and one slot 130 includes six or seven OFDM symbols. When one slot includes six symbols, it has a cyclic prefix length that is greater than the case in which one slot includes seven symbols.
As shown in FIG. 1 , one downlink frame 110 according to an exemplary embodiment of the present invention includes one synchronization interval 140 at the slot 0 and the slot 10 respectively, to thus include two synchronization intervals 140. However, the embodiment of the present invention is not restricted to this. That is, one downlink frame 110 may include a synchronization interval at a random slot, and may include one or at least three synchronization intervals. Also, since the length of the cyclic prefix may be different for each slot, it is desirable to provide the synchronization interval to the last position of the slot.
Each slot includes a pilot interval.
A synchronization interval according to an exemplary embodiment of the present invention includes a primary synchronization channel and a secondary synchronization channel, and the primary synchronization channel and the secondary synchronization channel are disposed adjacently with respect to time. As shown in FIG. 1 , a primary synchronization channel is provided to the last position of the slot, and a secondary synchronization channel is provided before the primary synchronization channel.
The primary synchronization channel includes information for identifying symbol synchronization and frequency synchronization, and some cell ID (identification) information, and the secondary synchronization channel includes information for identifying other cell ID information and frame synchronization. The mobile station identifies the cell ID through combination of cell ID information of the primary and secondary synchronization channels.
For example, when there are 510 cell IDs, three primary synchronization signals are allocated to the primary synchronization channel to divide the entire 510 cell IDs into three groups, and when 170 secondary synchronization signals are allocated to the secondary synchronization channel, the entire 510 cell ID information (3×170=510) can be expressed.
Further, it is also possible to divide the 510 cell IDs into 170 groups by using the 170 secondary synchronization signals allocated to the secondary synchronization channel, and express the cell ID information in the cell groups by using the three primary synchronization signals allocated to the primary synchronization channel.
Since the secondary synchronization channel includes information for identifying frame synchronization as well as cell ID information, two secondary synchronization channels included in one frame are different.
Referring to FIG. 2 to FIG. 3 , a secondary synchronization signal inserted into a secondary synchronization channel according to an exemplary embodiment of the present invention is configured by a combination of two sequences. Cell group information and frame synchronization information are mapped on the two sequences.
As shown in FIG. 2 , it is possible to allocate the first sequence to the subcarrier and sequentially allocate the second sequence to the other subcarrier, and as shown in FIG. 3 , it is possible to allocate the first sequence to every even subcarrier (n=0, 2, 4, and . . . 60) and the second sequence to every odd subcarrier (n=1, 3, 5, and . . . 61).
The length of sequence is half the number of subcarriers allocated to the secondary synchronization channel. That is, the number of elements of the sequence that can be generated is as many as half the number of subcarriers allocated to the secondary synchronization channel. For example, when the number of subcarriers allocated to the secondary synchronization channel is 62, the length of the sequence is 31, and up to 31 elements of the sequence can be generated.
Therefore, since two sequences are allocated to one secondary synchronization channel, 961 (=31×31) secondary synchronization signals are generated. However, since the information to be included by the secondary synchronization channel includes cell group information and frame boundary information, 170 or 340 (=170×2) secondary synchronization signals are needed. That is, 961 is sufficiently greater than 170 or 340.
A downlink frame generating device according to an exemplary embodiment of the present invention will now be described with reference to FIG. 4 . FIG. 4 shows a block diagram of a downlink frame generating device according to an exemplary embodiment of the present invention.
As shown in FIG. 4 , the downlink frame generating device includes a sequence generator 410, a synchronization signal generator 420, a frequency mapper 430, and an OFDM transmitter 440.
The sequence generator 410 generates a time and frequency synchronization acquiring sequence, a cell identifying sequence, a plurality of short sequences, and an adjacent cell interference reducing scrambling sequence, and transmits them to the synchronization signal generator 420.
The synchronization signal generator 420 generates a primary synchronization signal, a secondary synchronization signal, and a pilot pattern by using the sequences transmitted by the sequence generator 410.
The synchronization signal generator 420 generates a primary synchronization signal by using a time and frequency synchronization acquiring sequence and a cell identifying sequence. The synchronization signal generator 420 generates a secondary synchronization signal by using a plurality of short sequences and an adjacent cell interference reducing scrambling sequence.
The synchronization signal generator 420 generates a pilot pattern of a downlink signal by allocating a proper scrambling sequence that is allocated for each cell to the pilot channel so as to encode a common pilot symbol and a data symbol of the cellular system.
The frequency mapper 430 maps the primary synchronization signal, the secondary synchronization signal, and the pilot pattern generated by the synchronization signal generator 420, and frame control information and transmission traffic data provided from the outside in the time and frequency domains to generate a downlink frame.
The OFDM transmitter 440 receives the downlink frame from the frequency mapper 430 and transmits it through a transmitting antenna.
A downlink frame generating method according to an exemplary embodiment of the present invention will now be described with reference to FIG. 5 to FIG. 7 . FIG. 5 shows a flowchart of a downlink frame generating method according to an exemplary embodiment of the present invention.
As shown in FIG. 5 , the sequence generator 410 generates a plurality of short sequences and a plurality of adjacent cell interference reducing scrambling sequences and transmits them to the synchronization signal generator 420 (S510).
The synchronization signal generator 420 generates a secondary synchronization signal by using the short sequences and the adjacent cell interference reducing scrambling sequences transmitted by the sequence generator 410 (S520). The exemplary embodiment of the present invention will exemplify the frame including two secondary synchronization channels, but is not limited thereto.
Two secondary synchronization signal generating methods according to an exemplary embodiment of the present invention will now be described with reference to FIG. 6 and FIG. 7 . FIG. 6 shows a first method for generating a secondary synchronization signal according to an exemplary embodiment of the present invention, and FIG. 7 shows a second method for generating a secondary synchronization signal according to an exemplary embodiment of the present invention.
A short sequence (wn) is a binary sequence (binary code) indicating cell group information. That is, the short sequence (wn) is a binary sequence allocated for the cell group number and the frame synchronization, and its length is half the number of subcarriers allocated to the secondary synchronization channel. The exemplary embodiment of the present invention describes the case in which the number of subcarriers allocated to the secondary synchronization channel symbol is 62, but is not limited thereto. Therefore, the length of the short sequence according to the exemplary embodiment of the present invention is 31.
The first short sequence (w0) is a sequence allocated to the even subcarrier of the first (slot 0) secondary synchronization channel and is expressed in Equation 1.
w0=[w0(0),w0(1), . . . ,w0(k), . . . ,w0(30)] [Equation 1]
w0=[w0(0),w0(1), . . . ,w0(k), . . . ,w0(30)] [Equation 1]
Here, k represents an index of the even subcarrier used for the synchronization channel.
The second short sequence (w1) is a sequence allocated to the odd subcarrier of the first (slot 0) secondary synchronization channel and is expressed in Equation 2.
w1=[w1(0),w1(1), . . . ,w1(m), . . . ,w1(30)] [Equation 2]
w1=[w1(0),w1(1), . . . ,w1(m), . . . ,w1(30)] [Equation 2]
Here, m represents an index of the odd subcarrier used for the synchronization channel.
The third short sequence (w2) is a sequence allocated to the even subcarrier of the second (slot 10) secondary synchronization channel and is expressed in Equation 3.
w2=[w2(0),w2(1), . . . ,w2(k), . . . ,w2(30)] [Equation 3]
w2=[w2(0),w2(1), . . . ,w2(k), . . . ,w2(30)] [Equation 3]
The fourth short sequence (w3) is a sequence allocated to the odd subcarrier of the second (slot 10) secondary synchronization channel and is expressed in Equation 4.
w3=[w3(0),w3(1), . . . ,w3(m), . . . ,w3(30)] [Equation 4]
w3=[w3(0),w3(1), . . . ,w3(m), . . . ,w3(30)] [Equation 4]
w0, w1, w2, and w3 may be different sequences from each other, and it may be that w0=w3 and w1=w2, or it may be that w0=w2 and w1=w3. When it is given that w0=w3 and w1=w2, the short sequences of the second secondary synchronization channel can be allocated by using the short sequences allocated to the first synchronization channel, and a terminal only needs to memorize the 170 short sequences allocated to the first secondary synchronization channel and thereby reduce the complexity.
The first method for generating the secondary synchronization signal is to allocate the first short sequence to every even subcarrier of the first secondary synchronization channel and the second short sequence to every odd subcarrier of the first secondary synchronization channel as shown in FIG. 6 . The first method is then to allocate the third short sequence to every even subcarrier of the second secondary synchronization channel and the fourth short sequence to every odd subcarrier of the second secondary synchronization channel.
According to the first method for generating the secondary synchronization signal, since the secondary synchronization signal is generated by the combination of two short sequences with the length of 31, the number of the secondary synchronization signals becomes 961 which is sufficiently greater than the required number of 170 or 340.
The second method for generating the secondary synchronization signal is to allocate the first sequence determined by Equation 5 to every even subcarrier of the first (slot 0) secondary synchronization channel, and the second sequence determined by Equation 6 to every odd subcarrier of the first (slot 0) secondary synchronization channel, as shown in FIG. 7 . The second method also includes allocating the third sequence determined by Equation 7 to every even subcarrier of the second (slot 10) secondary synchronization channel, and the fourth sequence determined by Equation 8 to every odd subcarrier of the second (slot 10) secondary synchronization channel.
A scrambling sequence Pj,1 for scrambling the first short sequence w0 is given as Pj,1=[Pj,1(0), Pj,1(1), . . . Pj,1(k) . . . Pj,1(30)], and j (j=0, 1, 2) is a number of a cell identifying sequence allocated to the primary synchronization channel. Therefore, Pj,1 is determined by the primary synchronization signal. Pj,1 is a known value when the mobile station demaps the sequence in order to know the cell ID group and the frame boundary.
As expressed in Equation 5, respective elements of the first sequence c0 according to the second method for generating the secondary synchronization signal are products of respective elements of the first short sequence w0 and respective corresponding elements of Pj,1.
c0=[w0(0)Pj,1(0),w0(1)Pj,1(1), . . . ,w0(k)Pj,1(k), . . . ,w0(30)Pj,1(30)] [Equation 5]
c0=[w0(0)Pj,1(0),w0(1)Pj,1(1), . . . ,w0(k)Pj,1(k), . . . ,w0(30)Pj,1(30)] [Equation 5]
Here, k is an index of the even subcarrier used for the synchronization channel.
A scrambling sequence Sw0 for scrambling the second short sequence w1 is given as Sw0=[Sw0(0), Sw0(1), . . . , Sw0(m), . . . , Sw0(30)], and Sw0 is determined by the first short sequence (w0).
In this instance, it is possible to determine Sw0 according to the short sequence group to which the first short sequence belongs by combining the short sequences into a group.
For example, since the length of the short sequence is 31 in the exemplary embodiment of the present invention, there are 31 short sequences. Therefore, the 0 to 7 short sequences are set to belong to the group 0, the 8 to 15 short sequences are set to belong to the group 1, the 16 to 23 short sequences are set to belong to the group 2, and the 24 to 30 short sequences are set to belong to the group 3, a scrambling code is mapped on each group, and the scrambling code mapped on the group to which the first short sequence belongs is determined to be Sw0.
It is possible to divide the number of the short sequence by 8, combine the short sequences having the same residuals, and thereby classify the 31 short sequences as 8 groups. That is, the number of the short sequence is divided by 8, the short sequence having the residual 0 is set to belong to the group 0, the short sequence having the residual 1 is set to belong to the group 1, the short sequence having the residual 2 is set to belong to the group 2, the short sequence having the residual 3 is set to belong to the group 3, the short sequence having the residual 4 is set to belong to the group 4, the short sequence having the residual 5 is set to belong to the group 5, the short sequence having the residual 6 is set to belong to the group 6, the short sequence having the residual 7 is set to belong to the group 7, a scrambling code is mapped on each group, and the scrambling code mapped on the group to which the first short sequence belongs is determined to be Sw0.
As expressed in Equation 6, the respective elements of the second sequence c1 according to the second method for generating the secondary synchronization signal are products of the respective elements of the second short sequence w1 and the corresponding respective elements of Sw0.
c1[w1(0)Sw0(0),w1(1)Sw0(1), . . . ,w1(m)Sw0(m), . . . ,w1(30)Sw0(30)] [Equation 6]
c1[w1(0)Sw0(0),w1(1)Sw0(1), . . . ,w1(m)Sw0(m), . . . ,w1(30)Sw0(30)] [Equation 6]
Here, m is an index of the odd subcarrier used for the synchronization channel.
The scrambling sequence Pj,2 for scrambling the third short sequence w2 is given as Pj,2=[Pj,2(0), Pj,2(1), . . . Pj,2(k) . . . Pj,2(30)], and j (j=0, 1, 2) is a number of a cell identifying sequence allocated to the primary synchronization channel. Therefore, Pj,2 is determined by the primary synchronization signal. Pj,2 is a known value when the terminal demaps the code in order to know the cell ID group and the frame boundary.
As expressed in Equation 7, the respective elements of the third sequence c2 according to the second method for generating the secondary synchronization signal are products of the respective elements of the third short sequence w2 and the corresponding respective elements of Pj,2.
c2=[w2(0)Pj,2(0),w2(1)Pj,2(1), . . . ,w2(k)Pj,2(k), . . . ,w2(30)Pj,2(30)] [Equation 7]
c2=[w2(0)Pj,2(0),w2(1)Pj,2(1), . . . ,w2(k)Pj,2(k), . . . ,w2(30)Pj,2(30)] [Equation 7]
Here, k is an index of the even subcarrier used for the synchronization channel.
The scrambling sequence Sw2 for scrambling the fourth short sequence is given as Sw2=[Sw2(0), Sw2(1), Sw2(m), . . . Sw2(30)], and Sw2 is determined by the third short sequence w2.
In this instance, it is possible to combine the short sequences into a group and determine Sw2 according to the short sequence group to which the third short sequence belongs.
For example, since the length of the short sequence according to the exemplary embodiment of the present invention is 31, there are 31 short sequences. Therefore, the 0 to 7 short sequences are set to belong to the group 0, the 8 to 15 short sequences are set to belong to the group 1, the 16 to 23 short sequences are set to belong to the group 2, the 24 to 30 short sequences are set to belong to the group 3, a scrambling code is mapped on each group, and the scrambling code mapped on the group to which the third short sequence belongs is determine to be Sw2.
It is also possible to divide the number of the short sequence by 8, combine the short sequences with the same residual, and classify the 31 short sequences as 8 groups. That is, the number of the short sequence is divided by 8, the short sequence with the residual 0 is set to belong to the group 0, the short sequence with the residual 1 is set to belong to the group 1, the short sequence with the residual 2 is set to belong to the group 2, the short sequence with the residual 3 is set to belong to the group 3, the short sequence with the residual 4 is set to belong to the group 4, the short sequence with the residual 5 is set to belong to the group 5, the short sequence with the residual 6 is set to belong to the group 6, the short sequence with the residual 7 is set to belong to the group 7, a scrambling code is mapped on each group, and the scrambling code mapped on the group to which the third short sequence belongs is determined to be Sw2.
As expressed in Equation 8, the respective elements of the fourth sequence c3 according to the second method for generating the secondary synchronization signal are the products of the respective elements of the fourth short sequence and the corresponding respective elements of Sw2.
c3=[w3(0)S w20,w3(1)Sw2(1), . . . ,w3(m)Sw2(m), . . . ,w3(30)Sw2(30)] [Equation 8]
c3=[w3(0)
Here, m is an index of the odd subcarrier used for the synchronization channel.
Here, it is given that Pj,1=Pj,2, and w0≠w1≠w2≠w3 or w0=w3, w1=w2. In this case, the cell group and frame identifying information are mapped on the combination of the first to fourth short sequences, and the number of descrambling hypotheses of the terminal for the scramble of the secondary synchronization channel defined by the cell identifying sequence number of the primary synchronization channel is reduced.
It is set that Pj,1≠Pj,2 and w0=w2, w1=w3. In this case, cell group information is mapped on the combination of the first short sequence and the second short sequence, and frame synchronization information is mapped on the scrambling sequences Pj,1 and Pj,2 of the secondary synchronization channel defined by the cell identifying sequence number of the primary synchronization channel. The number of descrambling hypotheses of the terminal for the scramble of the secondary synchronization channel defined by the cell identifying sequence number of the primary synchronization channel is increased, but the complexity is reduced since the combination of cell group identifying sequences is reduced to half.
The frequency mapper 430 maps the secondary synchronization signal and the transmission traffic data generated by the synchronization signal generator 420 in the time and frequency domains to generate a frame of the downlink signal (S530).
The OFDM transmitter 440 receives the frame of the downlink signal and transmits it through the transmitting antenna (S540).
A method for a terminal to search for the cell by using a downlink signal according to an exemplary embodiment of the present invention will now be described with reference to FIG. 8 to FIG. 10 .
As shown in FIG. 8 , the cell searching device includes a receiver 810, a symbol synchronization estimation and frequency offset compensator 820, a Fourier transformer 830, and a cell ID estimator 840.
A cell searching method according to a first exemplary embodiment of the present invention will now be described with reference to FIG. 9 .
As shown in FIG. 9 , the receiver 810 receives the frame from the base station, and the symbol synchronization estimation and frequency offset compensator 820 filters the received signal by the bandwidth allocated to the synchronization channel, correlates the filtered received signal and a plurality of predetermined primary synchronization signals to acquire symbol synchronization, and estimates frequency synchronization to compensate for a frequency offset (S910). The symbol synchronization estimation and frequency offset compensator 820 correlates the filtered received signal and a plurality of predetermined primary synchronization signals, estimates the time having the greatest correlation value to be symbol synchronization, and transmits the number of the primary synchronization signal having the greatest correlation value to the cell ID estimator 840. In this instance, frequency offset is compensated in the frequency domain after Fourier transform.
The Fourier transformer 830 performs a Fourier transform process on the received signal with reference to the symbol synchronization estimated by the symbol synchronization estimation and frequency offset compensator 820 (S920).
The cell ID estimator 840 correlates the Fourier transformed received signal and a plurality of predetermined secondary synchronization signals to estimate a cell ID group and frame synchronization (S930). The cell ID estimator 840 correlates the Fourier transformed received signal and a plurality of secondary synchronization signals that are generated by applying Pj,1 and Pj,2 that are determined by the primary synchronization signal corresponding to the number of the primary synchronization signal transmitted by the symbol synchronization estimation and frequency offset compensator 820 to Equation 5 to Equation 8, and estimates the frame synchronization and the cell ID group by using the secondary synchronization signal having the greatest correlation value. In this instance, when the synchronization channel symbol in one frame is provided within one slot or one OFDM symbol, there is no need of additionally acquiring frame synchronization since the symbol synchronization becomes the frame synchronization.
The cell ID estimator 840 estimates the cell ID by using the number of the primary synchronization signal transmitted by the symbol synchronization estimation and frequency offset compensator 820 and the estimated cell ID group (S940). In this instance, the cell ID estimator 840 estimates the cell ID by referring to the mapping relation of the predetermined primary synchronization signal number, cell ID group, and cell ID.
The estimated cell ID information can be checked by using scrambling sequence information included in the pilot symbol interval.
A cell searching method according to a second exemplary embodiment of the present invention will now be described with reference to FIG. 10 .
The receiver 810 receives the frame from the base station, and the symbol synchronization estimation and frequency offset compensator 820 filters the received signal by the bandwidth allocated to the synchronization channel, correlates the filtered received signal and a plurality of predetermined primary synchronization signals to acquire symbol synchronization, and estimates frequency synchronization to compensate the frequency offset (S710). The symbol synchronization estimation and frequency offset compensator 820 correlates the filtered received signal and a plurality of predetermined primary synchronization signals to estimate the time having the greatest correlation value to be symbol synchronization, and transmits a plurality of correlation values that are generated by correlating the primary synchronization signals and the filtered received signal to the cell ID estimator 840. In this instance, the frequency offset can be compensated in the frequency domain after Fourier transform.
The Fourier transformer 830 performs a Fourier transform process on the received signal with reference to the symbol synchronization estimated by the symbol synchronization estimation and frequency offset compensator 820 (S720).
The cell ID estimator 840 estimates the cell ID by using a plurality of correlation values transmitted by the symbol synchronization estimation and frequency offset compensator 820, the Fourier transformed received signal, and correlation values of a plurality of predetermined secondary synchronization signals (S730). The cell ID estimator 840 correlates the Fourier transformed received signal and a plurality of secondary synchronization signals that are generated by applying Pj,1 and Pj,2 that are determined according to the corresponding primary synchronization signals to Equation 5 to Equation 8, and finds the secondary synchronization signal having the greatest correlation value, regarding a plurality of respective primary synchronization signals.
The cell ID estimator 840 combines the correlation value of the corresponding primary synchronization signal transmitted by the symbol synchronization estimation and frequency offset compensator 820 and the correlation value of the secondary synchronization signal having the greatest correlation value with the Fourier transformed received signal from among a plurality of secondary synchronization signals that are generated by applying Pj,1 and Pj,2 that are determined by the corresponding primary synchronization signal to Equation 5 to Equation 8, regarding a plurality of respective primary synchronization signals.
The cell ID estimator 840 estimates the frame synchronization and the cell ID group by using the secondary synchronization signal having the greatest value generated by combining the correlation value of the primary synchronization signal and the correlation value of the secondary synchronization signal. The cell ID estimator 840 estimates the cell ID by using the estimated cell ID group and the primary synchronization signal having the greatest value generated by combining the correlation value of the primary synchronization signal and the correlation value of the secondary synchronization signal. In this instance, the cell ID estimator 840 estimates the cell ID by referring to the mapping relation of the predetermined primary synchronization signal number, cell ID group, and cell ID.
The above-described embodiments can be realized through a program for realizing functions corresponding to the configuration of the embodiments or a recording medium for recording the program in addition to through the above-described device and/or method, which is easily realized by a person skilled in the art. Examples of the recording medium may include, but not limited to, a read only memory (ROM), a random access memory (RAM), an electrically programmable read-only memory (EEPROM), a flash memory, etc. The program may be executed by one or more hardware processors to achieve the function corresponding to the configuration of the exemplary embodiment. Examples of the hardware processor may include, but not limited to, a DSP (digital signal processor), a CPU (central processing unit), an ASIC (application specific integrated circuit), a programmable logic element, such as an FPGA (field programmable gate array), etc.
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims (75)
1. A method of searching for a cell in a mobile station, comprising:
receiving a downlink frame including a primary synchronization signal and a secondary synchronization signal, wherein the secondary synchronization signal contains cell identity group information and the primary synchronization signal contains cell identity information within a cell identity group; and
searching for a cell using the cell identity group information in the secondary synchronization signal and the cell identity information in the primary synchronization signal,
wherein the secondary synchronization signal comprises a first short sequence and a second short sequence, the first short sequence is scrambled with a first scrambling sequence, and the second short sequence is scrambled with a second scrambling sequence,
wherein the first scrambling sequence is determined based on the cell identity information contained in the primary synchronization signal, and the second scrambling sequence is determined based on the first short sequence.
2. The method of claim 1 , wherein the first short sequence scrambled with the first scrambling sequence and the second short sequence scrambled with the second scrambling sequence are alternately disposed on a plurality of sub-carriers.
3. The method of claim 1 , wherein the first scrambling sequence is different from the second scrambling sequence.
4. The method of claim 1 , wherein the downlink frame includes a plurality of slots, each slot having a plurality of symbols,
wherein the primary synchronization signal is located on a last symbol of a slot, and the secondary synchronization signal is located on a symbol right ahead of the last symbol of the slot.
5. The method of claim 1 , wherein the downlink frame comprises a second secondary synchronization signal containing the cell identity group information,
wherein the second secondary synchronization signal comprises the first short sequence and the second short sequence, the second short sequence is scrambled with the first scrambling sequence, and the first short sequence is scrambled with a third scrambling sequence, and
wherein the third scrambling sequence is determined based on the second short sequence.
6. The method of claim 5 , wherein the second short sequence scrambled with the first scrambling sequence and the first short sequence scrambled with the third scrambling sequence are alternately disposed on a plurality of sub-carriers.
7. The method of claim 5 , further comprising:
identifying the cell identity group using at least one of the first secondary synchronization signal and the second secondary synchronization signal.
8. The method of claim 5 , wherein the second secondary synchronization signal is different from the first secondary synchronization signal.
9. A method of searching for a cell by a mobile station in a wireless communication system, wherein the wireless communication system uses a plurality of short sequences grouped into a plurality of short sequence groups, the method comprising:
receiving a downlink frame including a primary synchronization signal and a secondary synchronization signal, wherein the secondary synchronization signal contains cell identity group information and the primary synchronization signal contains cell identity information within a cell identity group; and
searching for a cell using the cell identity group information in the secondary synchronization signal and the cell identity information in the primary synchronization signal,
wherein the secondary synchronization signal comprises a first short sequence and a second short sequence, the first short sequence is scrambled with a first scrambling sequence, and the second short sequence is scrambled with a second scrambling sequence,
wherein the first scrambling sequence is determined based on the cell identity information contained in the primary synchronization signal, and the second scrambling sequence is determined based on a short sequence group to which the first short sequence is assigned and is determined based on a remainder of dividing an index of the first short sequence by 8.
10. The method of claim 9 , wherein the wireless communication system has 31 short sequences, and the index of the first short sequence has one value among 0 to 30.
11. The method of claim 10 , wherein short sequences within the short sequence group have the same remainder.
12. The method of claim 9 , wherein the downlink frame comprises a second secondary synchronization signal containing the cell identity group information,
wherein the second secondary synchronization signal comprises the first short sequence and the second short sequence, the second short sequence is scrambled with the first scrambling sequence, and the first short sequence is scrambled with a third scrambling sequence,
wherein the third scrambling sequence is determined based on a short sequence group to which the second short sequence is assigned and is determined based on a remainder of diving an index of the second short sequence by 8.
13. The method of claim 12 , wherein the wireless communication system has 31 short sequences, and the index of the second short sequence has one value among 0 to 30.
14. The method of claim 13 , wherein short sequences within the short sequence group have the same remainder.
15. A method of searching for a cell by a mobile station in a wireless communication system, the method comprising:
receiving a downlink frame including a primary synchronization signal, a first secondary synchronization signal and a second secondary synchronization signal, wherein each of the first and second secondary synchronization signals contains cell identity group information and the primary synchronization signal contains cell identity information within a cell identity group; and
searching for a cell using the cell identity group information and the cell identity information, the cell identity group information being identified using at least one of the first secondary synchronization signal and the second secondary synchronization signal, and the cell identity information being identified using the primary synchronization signal,
wherein the first secondary synchronization signal comprises a first short sequence and a second short sequence, the first short sequence is scrambled with a first scrambling sequence, and the second short sequence is scrambled with a second scrambling sequence, and
the second secondary synchronization signal comprises the first short sequence and the second short sequence, the second short sequence is scrambled with the first scrambling sequence, and the first short sequence is scrambled with a third scrambling sequence, and
wherein the first scrambling sequence is determined based on the cell identity information contained in the primary synchronization signal, the second scrambling sequence is determined based on a remainder of dividing an index of the first short sequence by 8, and the third scrambling sequence is determined based on a remainder of dividing an index of the second short sequence by 8.
16. The method of claim 15 , wherein the first short sequence scrambled with the first scrambling sequence and the second short sequence scrambled with the second scrambling sequence in the first secondary synchronization signal are alternately disposed on a plurality of sub-carriers, and the second short sequence scrambled with the first scrambling sequence and the first short sequence scrambled with the third scrambling sequence in the second secondary synchronization signal are alternately disposed on a plurality of sub-carriers.
17. The method of claim 15 , wherein the first scrambling sequence is different from the second scrambling sequence.
18. The method of claim 15 , wherein the downlink frame includes a plurality of slots, each slot having a plurality of symbols,
wherein the primary synchronization signal is located on a last symbol of a first slot and the first secondary synchronization signal is located on a symbol right ahead of the last symbol of the first slot, and
the primary synchronization signal is located on a last symbol of a second slot and the second secondary synchronization signal is located on a symbol right ahead of the last symbol of the second slot.
19. The method of claim 15 , wherein the second secondary synchronization signal is different from the first secondary synchronization signal.
20. The method of claim 15 , wherein the wireless communication system has 31 short sequences, and
the index of the first short sequence has one value among 0 to 30, and the index of the second short sequence has one value among 0 to 30.
21. A method of generating a down link frame in a base station, comprising:
including cell identity group information in a secondary synchronization signal and including cell identity information within a cell identity group in a primary synchronization signal so that a terminal searches for a cell using the cell identity group information in the secondary synchronization signal and the cell identity information in the primary synchronization signal; and
generating a downlink frame including the primary synchronization signal and the secondary synchronization signal,
wherein the secondary synchronization signal comprises a first short sequence and a second short sequence, the first short sequence is scrambled with a first scrambling sequence, and the second short sequence is scrambled with a second scrambling sequence,
wherein the first scrambling sequence is determined based on the cell identity information contained in the primary synchronization signal, and the second scrambling sequence is determined based on the first short sequence.
22. The method of claim 21 , wherein the first short sequence scrambled with the first scrambling sequence and the second short sequence scrambled with the second scrambling sequence are alternately disposed on a plurality of sub-carriers.
23. The method of claim 21 , wherein the first scrambling sequence is different from the second scrambling sequence.
24. The method of claim 21 , wherein the downlink frame includes a plurality of slots, each slot having a plurality of symbols,
wherein the primary synchronization signal is located on a last symbol of a slot, and the secondary synchronization signal is located on a symbol right ahead of the last symbol of the slot.
25. The method of claim 21 , wherein the downlink frame comprises a second secondary synchronization signal containing the cell identity group information,
wherein the second secondary synchronization signal comprises the first short sequence and the second short sequence, the second short sequence is scrambled with the first scrambling sequence, and the first short sequence is scrambled with a third scrambling sequence, and
wherein the third scrambling sequence is determined based on the second short sequence.
26. The method of claim 25 , wherein the second short sequence scrambled with the first scrambling sequence and the first short sequence scrambled with the third scrambling sequence are alternately disposed on a plurality of sub-carriers.
27. The method of claim 25 , wherein the cell identity group is identified using at least one of the first secondary synchronization signal and the second secondary synchronization signal.
28. The method of claim 25 , wherein the second secondary synchronization signal is different from the first secondary synchronization signal.
29. A method of generating a downlink frame in a wireless communication system, wherein the wireless communication system uses a plurality of short sequences grouped into a plurality of short sequence groups, the method comprising:
including cell identity group information in a secondary synchronization signal and including cell identity information within a cell identity group in a primary synchronization signal so that a terminal searches for a cell using the cell identity group information in the secondary synchronization signal and the cell identity information in the primary synchronization signal; and
generating a downlink frame including the primary synchronization signal and the secondary synchronization signal,
wherein the secondary synchronization signal comprises a first short sequence and a second short sequence, the first short sequence is scrambled with a first scrambling sequence, and the second short sequence is scrambled with a second scrambling sequence,
wherein the first scrambling sequence is determined based on the cell identity information contained in the primary synchronization signal, and the second scrambling sequence is determined based on a short sequence group to which the first short sequence is assigned and is determined based on a remainder of dividing an index of the first short sequence by 8.
30. The method of claim 29 , wherein the wireless communication system has 31 short sequences, and the index of the first short sequence has one value among 0 to 30.
31. The method of claim 30 , wherein short sequences within the short sequence group have the same remainder.
32. The method of claim 29 , wherein the downlink frame comprises a second secondary synchronization signal containing the cell identity group information,
wherein the second secondary synchronization signal comprises the first short sequence and the second short sequence, the second short sequence is scrambled with the first scrambling sequence, and the first short sequence is scrambled with a third scrambling sequence,
wherein the third scrambling sequence is determined based on a short sequence group to which the second short sequence is assigned and is determined base on a remainder of diving an index of the second short sequence by 8.
33. The method of claim 32 , wherein the wireless communication system has 31 short sequences, and the index of the second short sequence has one value among 0 to 30.
34. The method of claim 33 , wherein short sequences within the short sequence group have the same remainder.
35. A method of generating a downlink frame in a wireless communication system, the method comprising:
including cell identity group information in each of first and second secondary synchronization signals and including cell identity information within a cell identity group in a primary synchronization signal so that a terminal searches for a cell using the cell identity group information and the cell identity information; and
generating a downlink frame including the primary synchronization signal, the first secondary synchronization signal and the second secondary synchronization signal; and
wherein the cell identity group information is identified using at least one of the first secondary synchronization signal and the second secondary synchronization signal, and the cell identity information is identified using the primary synchronization signal,
wherein the first secondary synchronization signal comprises a first short sequence and a second short sequence, the first short sequence is scrambled with a first scrambling sequence, and the second short sequence is scrambled with a second scrambling sequence,
wherein the second secondary synchronization signal comprises the first short sequence and the second short sequence, the second short sequence is scrambled with the first scrambling sequence, and the first short sequence is scrambled with a third scrambling sequence, and
wherein the first scrambling sequence is determined based on the cell identity information contained in the primary synchronization signal, the second scrambling sequence is determined based on a remainder of dividing an index of the first short sequence by 8, and the third scrambling sequence is determined based on a remainder of dividing an index of the second short sequence by 8.
36. The method of claim 35 , wherein the first short sequence scrambled with the first scrambling sequence and the second short sequence scrambled with the second scrambling sequence in the first secondary synchronization signal are alternately disposed on a plurality of sub-carriers, and the second short sequence scrambled with the first scrambling sequence and the first short sequence scrambled with the third scrambling sequence in the second secondary synchronization signal are alternately disposed on a plurality of sub-carriers.
37. The method of claim 35 , wherein the first scrambling sequence is different from the second scrambling sequence.
38. The method of claim 35 , wherein the downlink frame includes a plurality of slots, each slot having a plurality of symbols,
wherein the primary synchronization signal is located on a last symbol of a first slot and the first secondary synchronization signal is located on a symbol right ahead of the last symbol of the first slot, and
the primary synchronization signal is located on a last symbol of a second slot and the second secondary synchronization signal is located on a symbol right ahead of the last symbol of the second slot.
39. The method of claim 35 , wherein the second secondary synchronization signal is different from the first secondary synchronization signal.
40. The method of claim 35 , wherein the wireless communication system has 31 short sequences, and
the index of the first short sequence has one value among 0 to 30, and the index of the second short sequence has one value among 0 to 30.
41. A communication method, comprising:
receiving a first primary synchronization signal;
receiving a first secondary synchronization signal;
receiving a second primary synchronization signal;
receiving a second secondary synchronization signal;
determining a first identity based on the first secondary synchronization signal;
determining a second identity based on the first primary synchronization signal; and
determining a cell identifier based on the first identity and the second identity,
wherein the first secondary synchronization signal comprises a first sequence and a second sequence, the first sequence comprises a third sequence scrambled with a first scrambling sequence, and the second sequence comprises a fourth sequence scrambled with a second scrambling sequence,
wherein the first scrambling sequence is determined based on the second identity, and the second scrambling sequence is determined based on the first identity, and
wherein the first primary synchronization signal, the first secondary synchronization signal, the second primary synchronization signal, and the second secondary synchronization signal are received in a frame,
wherein the second secondary synchronization signal comprises a fifth sequence and a sixth sequence, the fifth sequence comprises the fourth sequence scrambled with the first scrambling sequence, and the sixth sequence comprises the third sequence scrambled with a third scrambling sequence.
42. The method of claim 41, wherein the frame comprises a plurality of subframes, the first primary synchronization signal is received in a first subframe, the first subframe includes a first plurality of slots, each slot having a first plurality of symbols, and
wherein the first primary synchronization signal is received on a last symbol of a first slot among the first plurality of slots.
43. The method of claim 42, wherein the second secondary synchronization signal is received in a second subframe, the second subframe includes a second plurality of slots, each slot having a second plurality of symbols, and
wherein the second secondary synchronization signal is received on a symbol immediately preceding a last symbol of a second slot among the second plurality of slots.
44. The method of claim 43, wherein the second secondary synchronization signal is received through a first number of sub-carriers of the symbol immediately preceding the last symbol of the second slot, and elements of the fifth sequence and elements of the sixth sequence are alternately disposed on the first number of sub-carriers.
45. The method of claim 43, wherein the first subframe is same as the second subframe.
46. The method of claim 41, wherein the first primary synchronization signal is identical to the second primary synchronization signal, the first scrambling sequence is different from the second scrambling sequence, and the first scrambling sequence is different from the third scrambling sequence.
47. The method of claim 46, wherein the first secondary synchronization signal is received on a first slot, and the second secondary synchronization signal is received on a second slot different from the first slot.
48. A communication method, comprising:
generating a first secondary synchronization signal based on a first identity;
generating a first primary synchronization signal based on a second identity;
transmitting the first primary synchronization signal;
transmitting the first secondary synchronization signal;
generating a second secondary synchronization signal based on the first identity;
generating a second primary synchronization signal based on the second identity;
transmitting the second primary synchronization signal; and
transmitting the second secondary synchronization signal,
wherein the first secondary synchronization signal comprises a first sequence and a second sequence, the first sequence comprises a third sequence scrambled with a first scrambling sequence, and the second sequence comprises a fourth sequence scrambled with a second scrambling sequence,
wherein the first scrambling sequence is determined based on the second identity, and the second scrambling sequence is determined based on the first identity,
wherein the first primary synchronization signal, the first secondary synchronization signal, the second primary synchronization signal, and the second secondary synchronization signal are transmitted in a frame, and
wherein the second secondary synchronization signal comprises a fifth sequence and a sixth sequence, the fifth sequence comprises the fourth sequence scrambled with the first scrambling sequence, and the sixth sequence comprises the third sequence scrambled with a third scrambling sequence.
49. The method of claim 48, wherein the frame comprises a plurality of subframes, the first primary synchronization signal is transmitted in a first subframe, the first subframe includes a first plurality of slots, each slot having a first plurality of symbols, and
wherein the first primary synchronization signal is transmitted on a last symbol of a first slot among the first plurality of slots.
50. The method of claim 49, wherein the second secondary synchronization signal is transmitted in a second subframe, the second subframe includes a second plurality of slots, each slot having a second plurality of symbols, and
wherein the second secondary synchronization signal is transmitted on a symbol immediately preceding a last symbol of a second slot among the second plurality of slots.
51. The method of claim 50, wherein the second secondary synchronization signal is received through a first number of sub-carriers of the symbol immediately preceding the last symbol of the second slot, and elements of the fifth sequence and elements of the sixth sequence are alternately disposed on the first number of sub-carriers.
52. The method of claim 50, wherein the first subframe is same as the second subframe.
53. The method of claim 48, wherein the first primary synchronization signal is identical to the second primary synchronization signal, the first scrambling sequence is different from the second scrambling sequence, and the first scrambling sequence is different from the third scrambling sequence.
54. The method of claim 53, wherein the first secondary synchronization signal is transmitted on a first slot, and the second secondary synchronization signal is transmitted on a second slot different from the first slot.
55. A terminal, comprising:
a circuitry which is configured to:
cause the terminal to receive a first primary synchronization signal;
cause the terminal to receive a first secondary synchronization signal;
cause the terminal to receive a second primary synchronization signal;
cause the terminal to receive a second secondary synchronization signal;
cause the terminal to determine a first identity based on the first secondary synchronization signal;
cause the terminal to determine a second identity based on the first primary synchronization signal; and
cause the terminal to determine a cell identifier based on the first identity and the second identity,
wherein the first secondary synchronization signal comprises a first sequence and a second sequence, the first sequence comprises a third sequence scrambled with a first scrambling sequence, and the second sequence comprises a fourth sequence scrambled with a second scrambling sequence,
wherein the first scrambling sequence is determined based on the second identity, and the second scrambling sequence is determined based on the first identity,
wherein the first primary synchronization signal, the first secondary synchronization signal, the second primary synchronization signal, and the second synchronization signal are received in a frame, and
wherein the second secondary synchronization signal comprises a fifth sequence and a sixth sequence, the fifth sequence comprises the fourth sequence scrambled with the first scrambling sequence, and the sixth sequence comprises the third sequence scrambled with a third scrambling sequence.
56. The terminal of claim 55, wherein the frame comprises a plurality of subframes, the first primary synchronization signal is received in a first subframe, the first subframe includes a first plurality of slots, each slot having a first plurality of symbols, and
wherein the first primary synchronization signal is received on a last symbol of a first slot among the first plurality of slots.
57. The terminal of claim 56, wherein the second secondary synchronization signal is received in a second subframe, the second subframe includes a second plurality of slots, each slot having a second plurality of symbols, and
wherein the second secondary synchronization signal is received on a symbol immediately preceding a last symbol of a second slot among the second plurality of slots.
58. The terminal of claim 57, wherein the second secondary synchronization signal is received through a first number of sub-carriers of the symbol immediately preceding the last symbol of the second slot, and elements of the fifth sequence and elements of the sixth sequence are alternately disposed on the first number of sub-carriers.
59. The terminal of claim 57, wherein the first subframe is same as the second subframe.
60. The terminal of claim 55, wherein the first primary synchronization signal is identical to the second primary synchronization signal, the first scrambling sequence is different from the second scrambling sequence, and the first scrambling sequence is different from the third scrambling sequence.
61. The terminal of claim 60, wherein the first secondary synchronization signal is received on a first slot, and the second secondary synchronization signal is received on a second slot different from the first slot.
62. A communication device for a terminal, the communication device comprising:
a circuitry which is configured to:
cause the terminal to receive a first primary synchronization signal;
cause the terminal to receive a first secondary synchronization signal;
cause the terminal to receive a second primary synchronization signal;
cause the terminal to receive a second secondary synchronization signal;
cause the terminal to determine a first identity based on the first secondary synchronization signal;
cause the terminal to determine a second identity based on the first primary synchronization signal; and
cause the terminal to determine a cell identifier based on the first identity and the second identity,
wherein the first secondary synchronization signal comprises a first sequence and a second sequence, the first sequence comprises a third sequence scrambled with a first scrambling sequence, and the second sequence comprises a fourth sequence scrambled with a second scrambling sequence,
wherein the first scrambling sequence is determined based on the second identity, and the second scrambling sequence is determined based on the first identity,
wherein the first primary synchronization signal, the first secondary synchronization signal, the second primary synchronization signal, and the second synchronization signal are received in a frame, and
wherein the second secondary synchronization signal comprises a fifth sequence and a sixth sequence, the fifth sequence comprises the fourth sequence scrambled with the first scrambling sequence, and the sixth sequence comprises the third sequence scrambled with a third scrambling sequence.
63. The communication device of claim 62, wherein the frame comprises a plurality of subframes, the first primary synchronization signal is received in a first subframe, the first subframe includes a first plurality of slots, each slot having a first plurality of symbols, and
wherein the first primary synchronization signal is received on a last symbol of a first slot among the first plurality of slots.
64. The communication device of claim 63, wherein the second secondary synchronization signal is received in a second subframe, the second subframe includes a second plurality of slots, each slot having a second plurality of symbols, and
wherein the second secondary synchronization signal is received on a symbol immediately preceding a last symbol of a second slot among the second plurality of slots.
65. The communication device of claim 64, wherein the second secondary synchronization signal is received through a first number of sub-carriers of the symbol immediately preceding the last symbol of the second slot, and elements of the fifth sequence and elements of the sixth sequence are alternately disposed on the first number of sub-carriers.
66. The communication device of claim 64, wherein the first subframe is same as the second subframe.
67. The communication device of claim 62, wherein the first primary synchronization signal is identical to the second primary synchronization signal, the first scrambling sequence is different from the second scrambling sequence, and the first scrambling sequence is different from the third scrambling sequence.
68. The terminal of claim 67, wherein the first secondary synchronization signal is received on a first slot, and the second secondary synchronization signal is received on a second slot different from the first slot.
69. A communication apparatus, comprising:
a circuitry configured to:
cause the communication apparatus to generate a first secondary synchronization signal based on a first identity;
cause the communication apparatus to generate a first primary synchronization signal based on a second identity;
cause the communication apparatus to transmit the first primary synchronization signal;
cause the communication apparatus to transmit the first secondary synchronization signal;
cause the communication apparatus to generate a second secondary synchronization signal based on the first identity;
cause the communication apparatus to generate a second primary synchronization signal based on the second identity;
cause the communication apparatus to transmit the second primary synchronization signal; and
cause the communication apparatus to transmit the second secondary synchronization signal,
wherein the first secondary synchronization signal comprises a first sequence and a second sequence, the first sequence comprises a third sequence scrambled with a first scrambling sequence, and the second sequence comprises a fourth sequence scrambled with a second scrambling sequence,
wherein the first scrambling sequence is determined based on the second identity, and the second scrambling sequence is determined based on the first identity,
wherein the first primary synchronization signal, the first secondary synchronization signal, the second primary synchronization signal, and the second secondary synchronization signal are transmitted in a frame, and
wherein the second secondary synchronization signal comprises a fifth sequence and a sixth sequence, the fifth sequence comprises the fourth sequence scrambled with the first scrambling sequence, and the sixth sequence comprises the third sequence scrambled with a third scrambling sequence.
70. The communication apparatus of claim 69, wherein the frame comprises a plurality of subframes, the first primary synchronization signal is transmitted in a first subframe, the first subframe includes a first plurality of slots, each slot having a first plurality of symbols, and
wherein the first primary synchronization signal is transmitted on a last symbol of a first slot among the first plurality of slots.
71. The communication apparatus of claim 70, wherein the second secondary synchronization signal is transmitted in a second subframe, the second subframe includes a second plurality of slots, each slot having a second plurality of symbols, and
wherein the second secondary synchronization signal is transmitted on a symbol immediately preceding a last symbol of a second slot among the second plurality of slots.
72. The communication apparatus of claim 71, wherein the second secondary synchronization signal is received through a first number of sub-carriers of the symbol immediately preceding the last symbol of the second slot, and elements of the fifth sequence and elements of the sixth sequence are alternately disposed on the first number of sub-carriers.
73. The communication apparatus of claim 71, wherein the first frame is same as the second frame.
74. The communication apparatus of claim 69, wherein the first primary synchronization signal is identical to the second primary synchronization signal, the first scrambling sequence is different from the second scrambling sequence, and the first scrambling sequence is different from the third scrambling sequence.
75. The communication apparatus of claim 74, wherein the first secondary synchronization signal is transmitted on a first slot, and the second secondary synchronization signal is transmitted on a second slot different from the first slot.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US16/813,737 USRE49665E1 (en) | 2007-07-12 | 2020-03-10 | Generating downlink frame and searching for cell |
Applications Claiming Priority (13)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR20070070086 | 2007-07-12 | ||
KR10-2007-0070086 | 2007-07-12 | ||
KR10-2007-0082678 | 2007-08-17 | ||
KR20070082678 | 2007-08-17 | ||
KR20070083916 | 2007-08-21 | ||
KR10-2007-0083916 | 2007-08-21 | ||
KR1020080061429A KR100921769B1 (en) | 2007-07-12 | 2008-06-27 | Method for generating downlink frame, and method for searching cell |
KR10-2008-0061429 | 2008-06-27 | ||
PCT/KR2008/004093 WO2009008678A2 (en) | 2007-07-12 | 2008-07-11 | Method for generating downlink frame, and method for searching cell |
US12/487,847 US8331406B2 (en) | 2007-07-12 | 2009-06-19 | Method for generating downlink frame, and method for searching cell |
US13/672,041 US8982911B2 (en) | 2007-07-12 | 2012-11-08 | Generating downlink frame and searching for cell |
US15/461,510 USRE47910E1 (en) | 2007-07-12 | 2017-03-17 | Generating downlink frame and searching for cell |
US16/813,737 USRE49665E1 (en) | 2007-07-12 | 2020-03-10 | Generating downlink frame and searching for cell |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/672,041 Reissue US8982911B2 (en) | 2007-07-12 | 2012-11-08 | Generating downlink frame and searching for cell |
Publications (1)
Publication Number | Publication Date |
---|---|
USRE49665E1 true USRE49665E1 (en) | 2023-09-19 |
Family
ID=40487883
Family Applications (6)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/488,234 Active 2029-11-28 US8331569B2 (en) | 2007-07-12 | 2009-06-19 | Method for generating downlink frame, and method for searching cell |
US12/487,786 Active 2030-03-21 US8325705B2 (en) | 2007-07-12 | 2009-06-19 | Method for generating downlink frame, and method for searching cell |
US12/487,847 Active 2029-12-14 US8331406B2 (en) | 2007-07-12 | 2009-06-19 | Method for generating downlink frame, and method for searching cell |
US13/672,041 Ceased US8982911B2 (en) | 2007-07-12 | 2012-11-08 | Generating downlink frame and searching for cell |
US15/461,510 Active 2029-01-16 USRE47910E1 (en) | 2007-07-12 | 2017-03-17 | Generating downlink frame and searching for cell |
US16/813,737 Active 2029-01-16 USRE49665E1 (en) | 2007-07-12 | 2020-03-10 | Generating downlink frame and searching for cell |
Family Applications Before (5)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/488,234 Active 2029-11-28 US8331569B2 (en) | 2007-07-12 | 2009-06-19 | Method for generating downlink frame, and method for searching cell |
US12/487,786 Active 2030-03-21 US8325705B2 (en) | 2007-07-12 | 2009-06-19 | Method for generating downlink frame, and method for searching cell |
US12/487,847 Active 2029-12-14 US8331406B2 (en) | 2007-07-12 | 2009-06-19 | Method for generating downlink frame, and method for searching cell |
US13/672,041 Ceased US8982911B2 (en) | 2007-07-12 | 2012-11-08 | Generating downlink frame and searching for cell |
US15/461,510 Active 2029-01-16 USRE47910E1 (en) | 2007-07-12 | 2017-03-17 | Generating downlink frame and searching for cell |
Country Status (10)
Country | Link |
---|---|
US (6) | US8331569B2 (en) |
EP (7) | EP2127156B1 (en) |
JP (3) | JP5171950B2 (en) |
KR (3) | KR100921769B1 (en) |
CN (4) | CN101578786B (en) |
AT (3) | ATE524888T1 (en) |
AU (3) | AU2008273133B2 (en) |
BR (3) | BRPI0807393A2 (en) |
ES (4) | ES2373002T3 (en) |
WO (3) | WO2009008678A2 (en) |
Families Citing this family (46)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007097597A2 (en) * | 2006-02-24 | 2007-08-30 | Lg Electronics Inc. | Methods of searching code sequence in mobile communication system |
KR100921769B1 (en) | 2007-07-12 | 2009-10-15 | 한국전자통신연구원 | Method for generating downlink frame, and method for searching cell |
KR20090009693A (en) | 2007-07-20 | 2009-01-23 | 한국전자통신연구원 | Method for generating downlink frame, and method for searching cell |
US8331331B2 (en) * | 2007-08-03 | 2012-12-11 | Qualcomm Incorporated | Method and apparatus for determining cell timing in a wireless communication system |
US8391392B2 (en) | 2009-01-05 | 2013-03-05 | Marvell World Trade Ltd. | Precoding codebooks for MIMO communication systems |
US8385441B2 (en) | 2009-01-06 | 2013-02-26 | Marvell World Trade Ltd. | Efficient MIMO transmission schemes |
US8238483B2 (en) | 2009-02-27 | 2012-08-07 | Marvell World Trade Ltd. | Signaling of dedicated reference signal (DRS) precoding granularity |
WO2010122432A1 (en) | 2009-04-21 | 2010-10-28 | Marvell World Trade Ltd | Multi-point opportunistic beamforming with selective beam attenuation |
US8265625B2 (en) * | 2009-08-20 | 2012-09-11 | Acer Incorporated | Systems and methods for network entry management |
KR101663322B1 (en) * | 2009-08-25 | 2016-10-07 | 한국전자통신연구원 | Syncronization control method for data transmission/receipt and station for data transmission/receipt syncronization |
US8675794B1 (en) | 2009-10-13 | 2014-03-18 | Marvell International Ltd. | Efficient estimation of feedback for modulation and coding scheme (MCS) selection |
US8917796B1 (en) | 2009-10-19 | 2014-12-23 | Marvell International Ltd. | Transmission-mode-aware rate matching in MIMO signal generation |
US8325860B2 (en) | 2009-11-09 | 2012-12-04 | Marvell World Trade Ltd. | Asymmetrical feedback for coordinated transmission systems |
US8761289B2 (en) * | 2009-12-17 | 2014-06-24 | Marvell World Trade Ltd. | MIMO feedback schemes for cross-polarized antennas |
EP2522099A4 (en) * | 2010-01-07 | 2014-12-31 | Marvell World Trade Ltd | Signaling of dedicated reference signal (drs) precoding granularity |
JP5258002B2 (en) | 2010-02-10 | 2013-08-07 | マーベル ワールド トレード リミテッド | Device, mobile communication terminal, chipset, and method in MIMO communication system |
US8687741B1 (en) * | 2010-03-29 | 2014-04-01 | Marvell International Ltd. | Scoring hypotheses in LTE cell search |
JP2012100254A (en) | 2010-10-06 | 2012-05-24 | Marvell World Trade Ltd | Codebook subsampling for pucch feedback |
US8615052B2 (en) | 2010-10-06 | 2013-12-24 | Marvell World Trade Ltd. | Enhanced channel feedback for multi-user MIMO |
KR20120042138A (en) * | 2010-10-22 | 2012-05-03 | 한국전자통신연구원 | Method for searching cell in wireless communication system |
US9048970B1 (en) | 2011-01-14 | 2015-06-02 | Marvell International Ltd. | Feedback for cooperative multipoint transmission systems |
WO2012108716A2 (en) * | 2011-02-11 | 2012-08-16 | 한국전자통신연구원 | Wireless communication system using multiple transmission and reception points |
US8861391B1 (en) | 2011-03-02 | 2014-10-14 | Marvell International Ltd. | Channel feedback for TDM scheduling in heterogeneous networks having multiple cell classes |
WO2012131612A1 (en) | 2011-03-31 | 2012-10-04 | Marvell World Trade Ltd. | Channel feedback for cooperative multipoint transmission |
US11696300B2 (en) | 2011-10-29 | 2023-07-04 | Comcast Cable Communications, Llc | Configuration of reduced transmission power time intervals based on traffic load |
US8937918B2 (en) | 2011-10-29 | 2015-01-20 | Ofinno Technologies, Llc | Efficient special subframe allocation |
US8971250B2 (en) | 2011-10-29 | 2015-03-03 | Ofinno Technologies, Llc | Special subframe allocation |
WO2013068916A1 (en) | 2011-11-07 | 2013-05-16 | Marvell World Trade Ltd. | Codebook sub-sampling for frequency-selective precoding feedback |
WO2013068915A2 (en) | 2011-11-07 | 2013-05-16 | Marvell World Trade Ltd. | Precoding feedback for cross-polarized antennas with magnitude information |
WO2013068974A1 (en) | 2011-11-10 | 2013-05-16 | Marvell World Trade Ltd. | Differential cqi encoding for cooperative multipoint feedback |
US20130142291A1 (en) * | 2011-12-05 | 2013-06-06 | Esmael Hejazi Dinan | Synchronization Signals Detection |
US8873467B2 (en) | 2011-12-05 | 2014-10-28 | Ofinno Technologies, Llc | Control channel detection |
US9220087B1 (en) | 2011-12-08 | 2015-12-22 | Marvell International Ltd. | Dynamic point selection with combined PUCCH/PUSCH feedback |
US8934436B2 (en) | 2011-12-31 | 2015-01-13 | Ofinno Technologies, L.L.C. | Special subframe configuration in wireless networks |
US8902842B1 (en) | 2012-01-11 | 2014-12-02 | Marvell International Ltd | Control signaling and resource mapping for coordinated transmission |
WO2013160795A1 (en) | 2012-04-27 | 2013-10-31 | Marvell World Trade Ltd. | Coordinated multipoint (comp) communication between base-stations and mobile communication terminals |
KR102053764B1 (en) * | 2012-08-01 | 2019-12-09 | 한국전자통신연구원 | Apparatus and method for detecting code |
US9078146B2 (en) * | 2012-09-10 | 2015-07-07 | Qualcomm Incorporated | Secondary synchronization signal (SSS) post-processing to eliminate short code collision induced false cells |
WO2014088659A1 (en) * | 2012-12-06 | 2014-06-12 | Intel Corporation | New carrier type (nct) information embedded in synchronization signal |
US8982853B2 (en) * | 2013-03-05 | 2015-03-17 | Qualcomm Incorporated | Methods and apparatus to control interference |
US9832691B2 (en) | 2014-01-30 | 2017-11-28 | Telefonaktiebolaget Lm Ericsson (Publ) | Cell ID expansion and hierarchical cell ID structures |
EP3026967A1 (en) * | 2014-08-19 | 2016-06-01 | Huawei Technologies Co., Ltd. | Synchronization signal transmitting device, receiving device, method, and system |
US11159355B2 (en) * | 2015-11-06 | 2021-10-26 | Apple Inc. | Synchronization signal design for narrowband Internet of Things communications |
CN106961313A (en) * | 2016-01-11 | 2017-07-18 | 中兴通讯股份有限公司 | The sending method and device of a kind of communication system auxiliary synchronous signals |
US10568102B2 (en) | 2017-02-23 | 2020-02-18 | Qualcomm Incorporated | Usage of synchronization signal block index in new radio |
WO2018201894A1 (en) * | 2017-05-05 | 2018-11-08 | 电信科学技术研究院有限公司 | Generation method and detection method for secondary synchronization sequence, base station, and user equipment |
Citations (52)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020044538A1 (en) | 2000-09-09 | 2002-04-18 | Samsung Electronics Co., Ltd. | Apparatus and method for searching a base station in an asynchronous mobile communications system |
US20020048315A1 (en) * | 2000-10-19 | 2002-04-25 | Ntt Docomo, Inc. | Spreading code synchronization method, receiver, and mobile station |
JP2003152595A (en) | 2001-10-17 | 2003-05-23 | National Univ Of Singapore | Cdma down-link receiver and method for reception |
US20030193922A1 (en) | 2002-04-16 | 2003-10-16 | Jan-Shin Ho | Method for cell search under effect of high clock offset |
CN1136668C (en) | 1997-08-29 | 2004-01-28 | 艾利森电话股份有限公司 | Synchronization to a base station and code acquisition within a spread spectrum communications system |
CN1494809A (en) | 2001-09-26 | 2004-05-05 | ���µ�����ҵ��ʽ���� | Method for searching cell and communication terminal device |
EP1453232A1 (en) | 2001-12-07 | 2004-09-01 | Matsushita Electric Industrial Co., Ltd. | MULTI−CARRIER TRANSMISSION/RECEPTION APPARATUS |
US6822999B1 (en) | 1999-11-13 | 2004-11-23 | Lg Electronics Inc. | High-speed cell searching apparatus and method for communication system |
US20050088987A1 (en) | 2003-09-16 | 2005-04-28 | Dong-Ryeol Ryu | Apparatus and method for searching for cell and multi-path in mobile communication system |
US6888880B2 (en) | 2000-01-11 | 2005-05-03 | Samsung Electronics Co., Ltd. | Apparatus for searching for a cell and method of acquiring code unique to each cell in an asynchronous wideband DS/CDMA receiver |
WO2005043791A2 (en) | 2003-10-30 | 2005-05-12 | Electronics And Telecommunications Research Institute | Method for constructing downlink frame in wireless communication system using orthogonal frequency division multiple access |
CN1669264A (en) | 2002-07-17 | 2005-09-14 | 皇家飞利浦电子股份有限公司 | Time-frequency interleaved MC-CDMA for quasi-synchronous systems |
US20060062185A1 (en) | 2002-11-01 | 2006-03-23 | Ipwireless, Inc. | Arrangement and method for sequence production in a spread spectrum communication system |
KR20060037101A (en) | 2004-10-27 | 2006-05-03 | 삼성전자주식회사 | Apparatus and method for generating dl/ul map messages in broadband wireless system |
US20060114812A1 (en) * | 2002-11-26 | 2006-06-01 | Kwang-Soon Kim | Method and apparatus for embodying and synchronizing downlink signal in mobile communication system and method for searching cell using the same |
US20060146867A1 (en) | 2002-12-13 | 2006-07-06 | Lee Lok-Kyu | Apparatus and method for signal constitution for downlink of ofdma-based cellular system |
US20060209670A1 (en) | 2005-03-17 | 2006-09-21 | Alexei Gorokhov | Pilot signal transmission for an orthogonal frequency division wireless communication system |
CN1879321A (en) | 2003-10-24 | 2006-12-13 | 韩国电子通信研究院 | Downlink signal configuring method and device in mobile communication system, and synchronization and cell searching method and device using the same |
WO2006134829A1 (en) | 2005-06-14 | 2006-12-21 | Ntt Docomo, Inc. | Transmitter, receiver, mobile communication system and synchronization channel transmission method |
US7158595B2 (en) | 2001-04-14 | 2007-01-02 | Samsung Electronics Co., Ltd. | Apparatus and method for acquiring frame synchronization in a mobile communication system |
US7161988B2 (en) | 2004-04-12 | 2007-01-09 | The Directv Group, Inc. | Method and apparatus for minimizing co-channel interference |
US20070041348A1 (en) * | 2005-08-19 | 2007-02-22 | Samsung Electronics Co., Ltd. | Transmitting/receiving apparatus and method for cell search in a broadband wireless communications system |
KR20070025944A (en) | 2005-09-05 | 2007-03-08 | 한국전자통신연구원 | Apparatus for generating down link signal, and method and apparatus for cell search in cellular system |
WO2007029958A1 (en) | 2005-09-05 | 2007-03-15 | Electronics And Telecommunications Research Institute | Apparatus for generating down link signal, and method and apparatus for cell search in cellular system |
KR20070039760A (en) | 2005-10-10 | 2007-04-13 | 한국전자통신연구원 | Apparatus and method for downlink initial synchronization and cell search of user terminal, and base station for transmitting downlink signal in ofdma mobile communication system |
CN1957539A (en) | 2004-04-12 | 2007-05-02 | 直视集团公司 | Methods and apparatuses for minimizing co-channel interference |
KR20070050338A (en) | 2005-11-10 | 2007-05-15 | 한국전자통신연구원 | Cell search method, forward link frame transmissin method, apparatus using the same and forward link frame structure |
WO2007055526A1 (en) | 2005-11-10 | 2007-05-18 | Electronics And Telecommunications Research Institute | Cell search method, forward link frame transmission method, apparatus using the same and forward link frame structure |
US7221695B1 (en) | 1999-08-17 | 2007-05-22 | Samsung Electronics Co., Ltd. | Method for communicating scrambling code ID in mobile communication system |
US7236468B2 (en) | 2001-10-08 | 2007-06-26 | Samsung Electronics Co., Ltd. | Apparatus and method for generating reference timing in a CDMA mobile communication system |
WO2007073116A1 (en) | 2005-12-22 | 2007-06-28 | Electronics And Telecommunications Research Institute | Method for demodulating broadcast channel by using synchronization channel at ofdm system with transmit diversity and transmitting/receiving device therefor |
US20080019350A1 (en) * | 2005-07-21 | 2008-01-24 | Onggosanusi Eko N | Downlink synchronization for a cellular ofdm communication system |
US20080019314A1 (en) | 2006-06-13 | 2008-01-24 | Qualcomm Incorporated | Reverse link pilot transmission for a wireless communication system |
US20080043702A1 (en) * | 2006-08-17 | 2008-02-21 | Samsung Electronics Co., Ltd. | Method and apparatus for cell search in a communication system |
US20080107086A1 (en) * | 2006-11-06 | 2008-05-08 | Motorola, Inc. | Method and apparatus for fast cell search |
US20080273522A1 (en) | 2007-05-01 | 2008-11-06 | Tao Luo | Generation and detection of synchronization signal in a wireless communication system |
US20080285529A1 (en) * | 2007-05-16 | 2008-11-20 | Samsung Electronics Co., Ltd. | Method and apparatus for transmitting/receiving pilot signal in a wireless communication system |
US20080285433A1 (en) | 2007-05-14 | 2008-11-20 | Motorola, Inc. | Reference sequence construction for fast cell search |
US20080291892A1 (en) | 2007-05-21 | 2008-11-27 | Qualcomm Incorporated | Assignment of primary and secondary synchronization code sequences to cells in a wireless communication system |
US20080291945A1 (en) | 2007-05-25 | 2008-11-27 | Tao Luo | Scrambling methods for synchronization channels |
WO2009008679A2 (en) | 2007-07-12 | 2009-01-15 | Electronics And Telecommunications Research Institute | Method for generating downlink frame, and method for searching cell |
WO2009014354A1 (en) | 2007-07-20 | 2009-01-29 | Electronics And Telecommunications Research Institute | Method for generating downlink frame, and method for searching cell |
US20090067370A1 (en) | 2005-11-10 | 2009-03-12 | Il-Gyu Kim | Cell search method in ofdm cellular system, frame transmission method thereof, and forward link frame structure |
US20090086669A1 (en) | 2007-10-01 | 2009-04-02 | Mccoy James W | Techniques for Reducing a Cell Identification Falsing Rate in a Wireless Communication System |
US20090219883A1 (en) * | 2006-01-18 | 2009-09-03 | Joon-Young Cho | Method and apparatus for transmitting synchronization signals in an ofdm based cellular communication system |
US20090310782A1 (en) | 2007-06-18 | 2009-12-17 | Texas Instruments Incorporated | Mapping schemes for secondary synchronization signal scrambling |
US20100135257A1 (en) | 2007-05-01 | 2010-06-03 | Ntt Docomo, Inc. | Base station, mobile station, and synchronization channel transmission method |
US20110009138A1 (en) * | 2007-07-19 | 2011-01-13 | Samsung Electronics Co., Ltd. | Method for generating downlink frame, and method for searching cell |
US20110129008A1 (en) * | 2008-06-24 | 2011-06-02 | Mieszko Chmiel | Methods, Apparatuses, System and Related Computer Program Product for Cell Type Detection |
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 |
JP2011250457A (en) | 2007-05-01 | 2011-12-08 | Ntt Docomo Inc | Base station apparatus and synchronization channel transmission method |
US8125976B2 (en) | 2006-08-28 | 2012-02-28 | Electronics And Telecommunications Research Institute | Apparatus for generating down link signal, and method and apparatus for cell search in cellular system |
-
2008
- 2008-06-27 KR KR1020080061429A patent/KR100921769B1/en active IP Right Grant
- 2008-07-03 KR KR1020080064202A patent/KR100921777B1/en active IP Right Grant
- 2008-07-10 KR KR1020080066782A patent/KR100921778B1/en active IP Right Grant
- 2008-07-11 CN CN2008800015866A patent/CN101578786B/en active Active
- 2008-07-11 EP EP08778753A patent/EP2127156B1/en active Active
- 2008-07-11 EP EP11161140.6A patent/EP2375589B1/en active Active
- 2008-07-11 ES ES08778751T patent/ES2373002T3/en active Active
- 2008-07-11 AU AU2008273133A patent/AU2008273133B2/en active Active
- 2008-07-11 BR BRPI0807393-7A2A patent/BRPI0807393A2/en not_active Application Discontinuation
- 2008-07-11 AT AT08778753T patent/ATE524888T1/en not_active IP Right Cessation
- 2008-07-11 AT AT08778751T patent/ATE524887T1/en not_active IP Right Cessation
- 2008-07-11 JP JP2010515976A patent/JP5171950B2/en active Active
- 2008-07-11 AU AU2008273134A patent/AU2008273134B2/en active Active
- 2008-07-11 EP EP08778752A patent/EP2127155B1/en active Active
- 2008-07-11 WO PCT/KR2008/004093 patent/WO2009008678A2/en active Application Filing
- 2008-07-11 JP JP2010515977A patent/JP5171951B2/en active Active
- 2008-07-11 ES ES11161138T patent/ES2417882T3/en active Active
- 2008-07-11 AU AU2008273132A patent/AU2008273132B2/en active Active
- 2008-07-11 EP EP11161139A patent/EP2375588B1/en active Active
- 2008-07-11 CN CN2008800015989A patent/CN101578787B/en active Active
- 2008-07-11 BR BRPI0807745-2A patent/BRPI0807745B1/en active IP Right Grant
- 2008-07-11 BR BRPI0807394-5A2A patent/BRPI0807394A2/en not_active Application Discontinuation
- 2008-07-11 EP EP11161138A patent/EP2375587B1/en active Active
- 2008-07-11 ES ES11161140T patent/ES2428348T3/en active Active
- 2008-07-11 AT AT08778752T patent/ATE528867T1/en not_active IP Right Cessation
- 2008-07-11 EP EP08778751A patent/EP2122864B1/en active Active
- 2008-07-11 WO PCT/KR2008/004095 patent/WO2009008680A2/en active Application Filing
- 2008-07-11 EP EP12197997.5A patent/EP2579478B1/en active Active
- 2008-07-11 JP JP2010515975A patent/JP5319671B2/en active Active
- 2008-07-11 ES ES11161139T patent/ES2402572T3/en active Active
- 2008-07-11 CN CN2008800015777A patent/CN101578785B/en active Active
- 2008-07-11 CN CN201310024487.2A patent/CN103442423B/en active Active
- 2008-07-11 WO PCT/KR2008/004094 patent/WO2009008679A2/en active Application Filing
-
2009
- 2009-06-19 US US12/488,234 patent/US8331569B2/en active Active
- 2009-06-19 US US12/487,786 patent/US8325705B2/en active Active
- 2009-06-19 US US12/487,847 patent/US8331406B2/en active Active
-
2012
- 2012-11-08 US US13/672,041 patent/US8982911B2/en not_active Ceased
-
2017
- 2017-03-17 US US15/461,510 patent/USRE47910E1/en active Active
-
2020
- 2020-03-10 US US16/813,737 patent/USRE49665E1/en active Active
Patent Citations (60)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1136668C (en) | 1997-08-29 | 2004-01-28 | 艾利森电话股份有限公司 | Synchronization to a base station and code acquisition within a spread spectrum communications system |
JP2004129286A (en) | 1997-08-29 | 2004-04-22 | Telefon Ab Lm Ericsson (Publ) | Synchronization to base station and code acquisition in spread spectrum communication system |
US7221695B1 (en) | 1999-08-17 | 2007-05-22 | Samsung Electronics Co., Ltd. | Method for communicating scrambling code ID in mobile communication system |
US6822999B1 (en) | 1999-11-13 | 2004-11-23 | Lg Electronics Inc. | High-speed cell searching apparatus and method for communication system |
US6888880B2 (en) | 2000-01-11 | 2005-05-03 | Samsung Electronics Co., Ltd. | Apparatus for searching for a cell and method of acquiring code unique to each cell in an asynchronous wideband DS/CDMA receiver |
US20020044538A1 (en) | 2000-09-09 | 2002-04-18 | Samsung Electronics Co., Ltd. | Apparatus and method for searching a base station in an asynchronous mobile communications system |
US20020048315A1 (en) * | 2000-10-19 | 2002-04-25 | Ntt Docomo, Inc. | Spreading code synchronization method, receiver, and mobile station |
US7158595B2 (en) | 2001-04-14 | 2007-01-02 | Samsung Electronics Co., Ltd. | Apparatus and method for acquiring frame synchronization in a mobile communication system |
EP1432265A1 (en) | 2001-09-26 | 2004-06-23 | Matsushita Electric Industrial Co., Ltd. | Cell search method and communication terminal apparatus |
CN1494809A (en) | 2001-09-26 | 2004-05-05 | ���µ�����ҵ��ʽ���� | Method for searching cell and communication terminal device |
US7236468B2 (en) | 2001-10-08 | 2007-06-26 | Samsung Electronics Co., Ltd. | Apparatus and method for generating reference timing in a CDMA mobile communication system |
JP2003152595A (en) | 2001-10-17 | 2003-05-23 | National Univ Of Singapore | Cdma down-link receiver and method for reception |
EP1453232A1 (en) | 2001-12-07 | 2004-09-01 | Matsushita Electric Industrial Co., Ltd. | MULTI−CARRIER TRANSMISSION/RECEPTION APPARATUS |
US7386055B2 (en) | 2001-12-07 | 2008-06-10 | Matsushita Electric Industrial Co., Ltd. | Multi-carrier transmission/reception apparatus |
US20030193922A1 (en) | 2002-04-16 | 2003-10-16 | Jan-Shin Ho | Method for cell search under effect of high clock offset |
CN1669264A (en) | 2002-07-17 | 2005-09-14 | 皇家飞利浦电子股份有限公司 | Time-frequency interleaved MC-CDMA for quasi-synchronous systems |
US20060045000A1 (en) | 2002-07-17 | 2006-03-02 | Koninklijke Philips Electronics N.V. | Time-frequency interleaved mc-cdma for quasi-synchronous systems |
US20060062185A1 (en) | 2002-11-01 | 2006-03-23 | Ipwireless, Inc. | Arrangement and method for sequence production in a spread spectrum communication system |
US20060114812A1 (en) * | 2002-11-26 | 2006-06-01 | Kwang-Soon Kim | Method and apparatus for embodying and synchronizing downlink signal in mobile communication system and method for searching cell using the same |
US20060146867A1 (en) | 2002-12-13 | 2006-07-06 | Lee Lok-Kyu | Apparatus and method for signal constitution for downlink of ofdma-based cellular system |
US20050088987A1 (en) | 2003-09-16 | 2005-04-28 | Dong-Ryeol Ryu | Apparatus and method for searching for cell and multi-path in mobile communication system |
CN1879321A (en) | 2003-10-24 | 2006-12-13 | 韩国电子通信研究院 | Downlink signal configuring method and device in mobile communication system, and synchronization and cell searching method and device using the same |
US20070133386A1 (en) | 2003-10-24 | 2007-06-14 | Kwang-Soon Kim | Downlink signal configurating method and device in mobile communication system, and synchronization and cell searching method and device using the same |
WO2005043791A2 (en) | 2003-10-30 | 2005-05-12 | Electronics And Telecommunications Research Institute | Method for constructing downlink frame in wireless communication system using orthogonal frequency division multiple access |
CN1957539A (en) | 2004-04-12 | 2007-05-02 | 直视集团公司 | Methods and apparatuses for minimizing co-channel interference |
US7161988B2 (en) | 2004-04-12 | 2007-01-09 | The Directv Group, Inc. | Method and apparatus for minimizing co-channel interference |
KR20060037101A (en) | 2004-10-27 | 2006-05-03 | 삼성전자주식회사 | Apparatus and method for generating dl/ul map messages in broadband wireless system |
US20060209670A1 (en) | 2005-03-17 | 2006-09-21 | Alexei Gorokhov | Pilot signal transmission for an orthogonal frequency division wireless communication system |
US20090323642A1 (en) | 2005-06-14 | 2009-12-31 | Ntt Docomo, Inc. | Transmitter, receiver, mobile communication system and synchronization channel |
WO2006134829A1 (en) | 2005-06-14 | 2006-12-21 | Ntt Docomo, Inc. | Transmitter, receiver, mobile communication system and synchronization channel transmission method |
US20080019350A1 (en) * | 2005-07-21 | 2008-01-24 | Onggosanusi Eko N | Downlink synchronization for a cellular ofdm communication system |
US20070041348A1 (en) * | 2005-08-19 | 2007-02-22 | Samsung Electronics Co., Ltd. | Transmitting/receiving apparatus and method for cell search in a broadband wireless communications system |
KR20070025944A (en) | 2005-09-05 | 2007-03-08 | 한국전자통신연구원 | Apparatus for generating down link signal, and method and apparatus for cell search in cellular system |
WO2007029958A1 (en) | 2005-09-05 | 2007-03-15 | Electronics And Telecommunications Research Institute | Apparatus for generating down link signal, and method and apparatus for cell search in cellular system |
US20080212462A1 (en) | 2005-09-05 | 2008-09-04 | Electronics And Telecommunications Research Instit | Apparatus for Generating Down Link Signal, and Method and Apparatus for Cell Search in Cellular System |
KR20070039760A (en) | 2005-10-10 | 2007-04-13 | 한국전자통신연구원 | Apparatus and method for downlink initial synchronization and cell search of user terminal, and base station for transmitting downlink signal in ofdma mobile communication system |
KR20070050338A (en) | 2005-11-10 | 2007-05-15 | 한국전자통신연구원 | Cell search method, forward link frame transmissin method, apparatus using the same and forward link frame structure |
US20090067370A1 (en) | 2005-11-10 | 2009-03-12 | Il-Gyu Kim | Cell search method in ofdm cellular system, frame transmission method thereof, and forward link frame structure |
WO2007055526A1 (en) | 2005-11-10 | 2007-05-18 | Electronics And Telecommunications Research Institute | Cell search method, forward link frame transmission method, apparatus using the same and forward link frame structure |
WO2007073116A1 (en) | 2005-12-22 | 2007-06-28 | Electronics And Telecommunications Research Institute | Method for demodulating broadcast channel by using synchronization channel at ofdm system with transmit diversity and transmitting/receiving device therefor |
US20090219883A1 (en) * | 2006-01-18 | 2009-09-03 | Joon-Young Cho | Method and apparatus for transmitting synchronization signals in an ofdm based cellular communication system |
US8873488B2 (en) | 2006-01-18 | 2014-10-28 | Samsung Electronics Co., Ltd | Method and apparatus for transmitting synchronization signals in an OFDM based cellular communications system |
US20080019314A1 (en) | 2006-06-13 | 2008-01-24 | Qualcomm Incorporated | Reverse link pilot transmission for a wireless communication system |
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 |
US20080043702A1 (en) * | 2006-08-17 | 2008-02-21 | Samsung Electronics Co., Ltd. | Method and apparatus for cell search in a communication system |
US8125976B2 (en) | 2006-08-28 | 2012-02-28 | Electronics And Telecommunications Research Institute | Apparatus for generating down link signal, and method and apparatus for cell search in cellular system |
US20080107086A1 (en) * | 2006-11-06 | 2008-05-08 | Motorola, Inc. | Method and apparatus for fast cell search |
JP2011250457A (en) | 2007-05-01 | 2011-12-08 | Ntt Docomo Inc | Base station apparatus and synchronization channel transmission method |
US20100135257A1 (en) | 2007-05-01 | 2010-06-03 | Ntt Docomo, Inc. | Base station, mobile station, and synchronization channel transmission method |
US20080273522A1 (en) | 2007-05-01 | 2008-11-06 | Tao Luo | Generation and detection of synchronization signal in a wireless communication system |
US20080285433A1 (en) | 2007-05-14 | 2008-11-20 | Motorola, Inc. | Reference sequence construction for fast cell search |
US20080285529A1 (en) * | 2007-05-16 | 2008-11-20 | Samsung Electronics Co., Ltd. | Method and apparatus for transmitting/receiving pilot signal in a wireless communication system |
US20080291892A1 (en) | 2007-05-21 | 2008-11-27 | Qualcomm Incorporated | Assignment of primary and secondary synchronization code sequences to cells in a wireless communication system |
US20080291945A1 (en) | 2007-05-25 | 2008-11-27 | Tao Luo | Scrambling methods for synchronization channels |
US20090310782A1 (en) | 2007-06-18 | 2009-12-17 | Texas Instruments Incorporated | Mapping schemes for secondary synchronization signal scrambling |
WO2009008679A2 (en) | 2007-07-12 | 2009-01-15 | Electronics And Telecommunications Research Institute | Method for generating downlink frame, and method for searching cell |
US20110009138A1 (en) * | 2007-07-19 | 2011-01-13 | Samsung Electronics Co., Ltd. | Method for generating downlink frame, and method for searching cell |
WO2009014354A1 (en) | 2007-07-20 | 2009-01-29 | Electronics And Telecommunications Research Institute | Method for generating downlink frame, and method for searching cell |
US20090086669A1 (en) | 2007-10-01 | 2009-04-02 | Mccoy James W | Techniques for Reducing a Cell Identification Falsing Rate in a Wireless Communication System |
US20110129008A1 (en) * | 2008-06-24 | 2011-06-02 | Mieszko Chmiel | Methods, Apparatuses, System and Related Computer Program Product for Cell Type Detection |
Non-Patent Citations (34)
Title |
---|
3GPP TS 36.211 V8.1.0, "Synchronization signals," Chapter 6.11, pp. 46-49 (2007). |
3GPP TS 36.211 V8.2.0, "Synchronization signals," Chapter 6.11, pp. 57-60 (2008). |
Ericsson, "Information mapping on the Secondary Synchronization Signal," 3GPP TSG-RAN WG 1 Meeting #50, R1-073736, 12 pages, (2007). |
Ericsson, "Synchronization signals for LTE," 3GPP TSG-RAN WG1 Meeting #49bis, R1-073023, 6 pages, (2007). |
ETRI, "Cell Search approach 1: Further considerations," 3GPP TSG RAN1 WG1 #47, R1-063520, 6 pages, (2006). |
ETRI, "Comparison of S-SCH mapping methods," 3GPP TSG WG1 #50bis, R1-074052 (2007). |
ETRI, "Design of S-SCH sequences," 3GPP TSG RAN1 WG1 #49bis, R1-072811, 5 pages (2007). |
ETRI, "S-SCH scrambling and mapping methods," 3GPP TSG RAN1 WG1 #50, R1-073414, 8 pages, (2007). |
ETRI, "S-SCH scrambling and mapping methods," 3GPP TSG RAN1 WG1 #50, R1-073798, 8 pages, (2007). |
ETRI, "S-SCH Scrambling Methods," 3GPP TSH RAN WG1 Meeting #50bis, R1-074053 (2007). |
Huawei, "Scrambling and information encoding for the S-SCH," TSG RAN WG1 meeting #50, R1-073514, 6 pages, (2007). |
LG Electronics, "SSC mapping and scrambling; method," 3GPP RSG RAN WG1 #50, R1-073496, 9 pages, (2007). |
LG Electronics, "Time-domain PSC design using Zadoff-Chu sequence," 3GPP TSG RAN WG1 #48 bis, R1-071530, 13 references, (2007). |
Marvell Semiconductor, "SSCH Mapping to Group ID and Frame Timing," 3GPP TSG RAN WG1 #50bis, R1-074485 (2007). |
MCC Support, "Draft Report of 3GPP TSG RAN WG1 #49b v0.3.0," 3GPP TSG RAN WG1 Meeting #50, R1-073815, 4 pages (2007). |
Motorola, "Cell Search E-mail Reflector Summary," 3GPP TSG RAN1#50, R1-073401, 1 page (2007). |
Motorola, "Scrambling Method for Two S-SCH Short Code," 3GPP TSG RAN WG1 Meeting #49bis, R1-072661 (2007). |
Nokia Siemens Networks, Nokia, "On the multiplexing structure of the primary broadcast channel," 3GPP TSG RAN WG1 #49bis Meeting, R1-072962, 8 pages, (2007). |
Nortel, "Scrambling Code Designs for S-SCH," 3GPP TSG-RAN WG1 Meeting #50, R1-073307, 6 pages (2007). |
Notice of Allowance for U.S. Appl. No. 12/487,747 dated Aug. 30, 2012. |
Notice of Allowance for U.S. Appl. No. 13/672,041 dated Nov. 5, 2014. |
Notice of Allowance for U.S. Appl. No. 15/461,510 dated Oct. 18, 2019. |
NTT DoCoMo et al., "Scrambling Method for S-SCH in E-UTRA Downlink," 3GPP TSG RAN WG1 Meeting #49bis, R1-072940, 4 pages, (2007). |
NTT DoCoMo et al., "S-SCH Structure for E-UTRA Downlink," 3GPP TSG RAN WG1 Meeting #49bis, R1-072941, 6 pages (2007). |
NTT DoCoMo, Mitsubishi Electric, Sharp, Toshiba Corporation, "S-SCH Structure for E-UTRA Downlink," 3GPP TSG RAN WG1 Meeting #49, R1-072598 (2007). |
Office Action for U.S. Appl. No. 12/487,747 dated Mar. 26, 2012. |
Office Action for U.S. Appl. No. 12/487,747 dated Nov. 3, 2011. |
Office Action for U.S. Appl. No. 13/672,041 dated Jul. 16, 2014. |
Office Action for U.S. Appl. No. 15/461,510 dated Feb. 13, 2019. |
Office Action for U.S. Appl. No. 15/461,510 dated May 17, 2018. |
Sharp, "Proposed Scrambling sequences for S-SCH with embedded frame timing derivation," 3GPP TSG RAN WG1 Meeting #50, R1-073323, 12 pages, (2007). |
Supplementary European Search Report for Application No. 08778878.2, dated Feb. 15, 2010. |
ZTE, "Scrambling Method for S-SCH," 3GPP TSG-RAN WG1 #49bis, R1-072910 (2007). |
ZTE, Catt, "System Information Mapping Scheme for S-SCH Sequences," 3GPP TSG-RAN WG1 #50, R1-073590, 6 pages, (2007). |
Also Published As
Similar Documents
Publication | Publication Date | Title |
---|---|---|
USRE49665E1 (en) | Generating downlink frame and searching for cell | |
US11870546B2 (en) | Generating downlink frame and searching for cell |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
FEPP | Fee payment procedure |
Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |