JP3634793B2 - Mobile communication system and method using multi-carrier CDMA system using scramble code - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transmission technique and a reception technique in a mobile communication system for performing spreading code synchronization on the receiving side in a multicarrier CDMA system using a long-period spreading code (scramble code).
[0002]
[Prior art]
In the following description, the “scramble code” is a “long-period spreading code” in the claims.
[0003]
In a multicarrier transmission scheme such as a multicarrier code division multiple access (MC-CDMA) scheme or an OFDM (Orthogonal Frequency Division Multiplexing) modulation scheme, an information signal is modulated by a plurality of subcarriers on the transmission side, and multipath A guard interval is inserted into the transmission signal for the purpose of reducing waveform distortion due to the delayed wave.
[0004]
FIG. 1 shows a configuration of a conventional MC-CDMA transmission apparatus 1000. The transmission apparatus 1000 includes an appropriate number of data channel generation circuits 100. In each data channel generation circuit 100, the transmission data sequence input from the transmission data generation unit 101 is encoded by the transmission path encoder 102, and data modulation is performed by the data modulation unit 103. Then, pilot symbols are multiplexed on the modulated data sequence in multiplexing section 104, and serial / parallel conversion section 105 performs serial / parallel conversion to N / SF information symbol sequences on the frequency axis. The N / SF information symbol sequences on the frequency axis that have been subjected to serial-parallel conversion are copied by the copying unit 106 by the number of symbols SF equal to the sequence length of the short-period spreading code for each information symbol and arranged on the frequency axis. . Multiplier 108 multiplies the arranged information symbol sequences on the frequency axis by the short period spreading code generated by short period spreading code generator 107.
[0005]
The combining unit 109 multiplexes the symbol sequence on the frequency axis of the sequence length N multiplied by each short period spreading code (short code) output from each data channel generation circuit 100. The multiplexed symbol sequence having the sequence length N is multiplied in the frequency direction by the scramble code output from the scramble code generator 110 in each of the N multipliers 111 and input to the inverse Fourier transform circuit (IFFT) 113.
[0006]
The inverse Fourier transform circuit 113 converts the signal into orthogonal subcarrier signals of N subcarriers. Then, a GI is inserted into the multicarrier signal by the guard interval inserter 114. Then, the transmission apparatus 1000 converts the multicarrier signal output from the guard interval inserter 114 into a radio signal and transmits it to the space.
[0007]
The mobile station on the receiving side receives the radio multicarrier signal transmitted from the transmitting apparatus 1000 and removes the guard interval inserted on the transmitting side from the received multicarrier signal. The receiving side further performs FFT (Fast Fourier Transform) on the multicarrier signal from which the guard interval has been removed to separate it into N subcarrier components and demodulates them. For this reason, the reception side needs to detect the reception timing of the guard interval, that is, the FFT timing, before the FFT.
[0008]
As a method for detecting the FFT timing in the multicarrier transmission method using the OFDM modulation method, there is known a method for detecting the FFT timing by correlating the guard interval portion inserted for each symbol (“multicarrier”). "Symbol synchronization and frequency offset simultaneous estimation method of modulated signal", Mori, Okada, Hara, Komaki, Morinaga, IEICE Technical Report RCS95-70, pp. 9-16, 1995-09). Also, a method is known in which the same signal is transmitted twice as a timing detection signal, and the FFT timing is detected by taking a correlation between two symbols on the receiving side (“OFDM modulation scheme for high-speed wireless LAN”). , Onizawa, Mizoguchi, Kumagai, Takanashi, Morikura, IEICE Technical Report RCS97-210, pp.137-142, 1998-01).
[0009]
In the MC-CDMA system, a communication person is identified by a short-period spreading code assigned to each communication person. For this reason, a plurality of communicators can simultaneously communicate using the same frequency band.
[0010]
[Problems to be solved by the invention]
When the above-described MC-CDMA system is used for mobile communication, it is necessary to use a scramble code in order to identify a base station. For this reason, a receiver for the MC-CDMA system must be able to identify the scramble code along with the detection of the FFT timing. In order to make this possible, the mobile station side needs to detect the correlation for all the scramble codes prepared in the system and detect the scramble code multiplied by the signal of the base station to be connected. is there. Considering flexible scramble code allocation, the number of scramble codes prepared in the system is about several hundreds. If it is going to cope with this, when a mobile station starts communication, it will take a long time to detect a scramble code. However, to date, research on MC-CDMA has been mainly related to link level evaluation and nothing related to identification of scramble codes.
[0011]
The present invention has been made to solve such a problem, and the object of the present invention is to provide a MC-CDMA system using a scramble code for identifying each of a plurality of base stations in the receiving station side. Is to provide a transmission technique and a reception technique in a mobile communication system that can detect a spread code at high speed and with high accuracy.
[0012]
The present invention also provides a signal reception technique capable of detecting the FFT timing of the optimum cell by providing a plurality of candidates as optimum base stations on the receiving side in the MC-CDMA mobile communication system. Objective.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the first feature of the present invention is that a short period spreading code product unit that multiplies each of a plurality of transmission data sequences by a plurality of short period spreading codes, and the short period spreading code multiplication. A long-period spread code product unit that multiplies a plurality of transmission-use data sequences multiplied by a short-period spread code output from the product unit, and a synchronization signal for the synchronization signal data. The transmission data obtained by multiplying the synchronization signal generating unit that multiplies and outputs the spreading code for use, and the short cycle spreading code and the long cycle spreading code that are output from the long cycle spreading code product unit. Each sequence is transmitted using a plurality of subcarriers, and a synchronization signal obtained by multiplying the synchronization signal data output from the synchronization signal generation unit with only a synchronization signal spreading code is transmitted as one or more subcarriers. Send using A transmitting device in a mobile communication system of MC-CDMA system comprising a signal processing unit.
[0014]
The second feature of the present invention is that a data sequence obtained by multiplying a short-period spreading code and a long-period spreading code is transmitted using a plurality of subcarriers, and is multiplied only by a synchronization signal spreading code. The transmission method in the mobile communication system is characterized by transmitting the synchronized signal using one or a plurality of subcarriers.
[0015]
A third feature of the present invention is that a data sequence obtained by multiplying a short-period spreading code and any one long-period spreading code included in the long-period spreading code group is transmitted using a plurality of subcarriers. A signal receiving unit for receiving a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code, in a MC-CDMA mobile communication system, A correlator for obtaining a correlation value between the multicarrier signal received by the signal receiving unit and a synchronization signal replica, and an FFT timing and a reception timing of the long-period spread code according to the correlation value obtained by the correlator And a timing detection unit for detecting.
[0016]
A fourth feature of the present invention is that a data series obtained by multiplying a short-period spreading code and any one long-period spreading code included in a long-period spreading code group is transmitted using a plurality of subcarriers. A signal receiving unit for receiving a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code, in a MC-CDMA mobile communication system, A first correlator for obtaining a correlation value between the multicarrier signal received by the signal receiving unit and a synchronization signal replica, and an FFT timing and the length according to the correlation value obtained by the first correlator A timing detector that detects the reception timing of the periodic spread code, and performs FFT according to the FFT timing detected by the timing detector, A plurality of subcarrier components separated by the FFT circuit according to the reception timing of the long-period spreading code detected by the timing detector, and the long-period spreading code group A second correlator for obtaining a correlation value between a code sequence obtained by multiplying each long-period spreading code and the short-period spreading code included in the second correlator, and the correlation value obtained by the second correlator And a code detection unit for detecting a long-period spread code for spreading the multicarrier signal, a reception timing of the long-cycle spread code detected by the timing detection unit, and the long-period spread detected by the code detection unit And a demodulation circuit that demodulates the data series from the multicarrier signal received by the signal reception unit using a code.
[0017]
A fifth feature of the present invention is that a data series obtained by multiplying a short-period spreading code and any one long-period spreading code included in a long-period spreading code group is transmitted using a plurality of subcarriers. A signal receiving unit for receiving a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code, in a MC-CDMA mobile communication system, A subcarrier separation unit that separates the multicarrier signal received by the signal reception unit into a plurality of subcarrier components, and a subcarrier component that includes the synchronization signal among the plurality of subcarrier components separated by the subcarrier separation unit A correlator for obtaining a correlation value between a carrier component and a synchronization signal replica, and detecting a reception timing of the long-period spread code according to the correlation value obtained by the correlator. Is obtained and a timing detection unit that.
[0018]
A sixth feature of the present invention is that a data sequence obtained by multiplying a short-period spreading code and any one long-period spreading code included in the long-period spreading code group is transmitted using a plurality of subcarriers. A signal receiving unit for receiving a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code, in a MC-CDMA mobile communication system, The multicarrier signal received by the signal receiving unit is subjected to FFT according to a plurality of FFT timings and separated into a plurality of subcarrier components, and the plurality of subcarriers separated by the subcarrier separating unit Among the carrier components, a correlator for obtaining a correlation value between a subcarrier component included in the synchronization signal and the synchronization signal replica, and a correlation value obtained by the correlator. Te, in which a timing detector for detecting the reception timing and FFT timing of the long period spreading code.
[0019]
A seventh feature of the present invention is that a data sequence obtained by multiplying a short-period spreading code and any one long-period spreading code included in a long-period spreading code group is transmitted using a plurality of subcarriers. A signal receiving unit for receiving a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code, in a MC-CDMA mobile communication system, A subcarrier separation unit that separates the multicarrier signal received by the signal reception unit into a plurality of subcarrier components, and a subcarrier component that includes the synchronization signal among the plurality of subcarrier components separated by the subcarrier separation unit A first correlator for obtaining a correlation value between a carrier component and a synchronization signal replica; and a receiver for the long-period spreading code according to the correlation value obtained by the first correlator. A timing detection unit that detects a ming, a plurality of subcarrier components separated by the subcarrier separation unit according to a reception timing of the long period spreading code detected by the timing detection unit, and the long period spreading code group A second correlator for obtaining a correlation value between a code sequence obtained by multiplying each of the long-period spreading code and the short-period spreading code, and a correlation value obtained by the second correlator. Accordingly, a code detection unit that detects a long-period spreading code that spreads the multicarrier signal, a reception timing of the long-period spreading code detected by the timing detection unit, and the long-period spreading code detected by the code detection unit And a demodulating circuit for demodulating the data series from the multicarrier signal received by the signal receiving unit.
[0020]
The eighth feature of the present invention is that a data sequence in which a short-period spreading code and any one long-period spreading code included in a long-period spreading code group are multiply multiplied is transmitted using a plurality of subcarriers. A signal receiving unit for receiving a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code, in a MC-CDMA mobile communication system, The multicarrier signal received by the signal receiving unit is subjected to FFT according to a plurality of FFT timings and separated into a plurality of subcarrier components, and the plurality of subcarriers separated by the subcarrier separating unit Of the carrier components, a first correlator that obtains a correlation value between a subcarrier component included in the synchronization signal and a synchronization signal replica, and the first correlator obtains the correlation value. According to the correlation value, a timing detection unit that detects the reception timing and FFT timing of the long-period spreading code, and performs FFT according to the FFT timing detected by the timing detection unit, the multicarrier signal The FFT circuit that separates into subcarrier components, and a plurality of subcarrier components separated by the FFT circuit according to the reception timing of the long period spreading code detected by the timing detection unit, and included in the long period spreading code group A second correlator that obtains a correlation value between a code sequence obtained by multiplying each long-period spreading code and the short-period spreading code, and the correlation value obtained by the second correlator A code detection unit for detecting a long-period spreading code for spreading the multicarrier signal, and reception of the long-period spreading code detected by the timing detection unit Using said long period spreading code timing and the code detecting section detects, is from the multi-carrier signal by the signal receiving unit receives those with a demodulation circuit for demodulating the data sequence.
[0021]
A ninth feature of the present invention is that a data series obtained by multiplying a short-period spreading code and any one long-period spreading code included in the long-period spreading code group is transmitted using a plurality of subcarriers. A receiving apparatus in an MC-CDMA mobile communication system that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers with a synchronization signal spreading code. signal A receiving unit; a subcarrier separating unit that performs FFT on the multicarrier signal received by the signal receiving unit according to each of a plurality of FFT timings to separate a plurality of sets of subcarrier components; and the subcarrier separation A first correlator for obtaining a correlation value between a subcarrier component including the synchronization signal and a synchronization signal replica among the plurality of subcarrier components separated by a unit, and the correlation value obtained by the correlator A timing detection unit that detects a plurality of reception timing candidates of the long-period spreading code, and a plurality of sets of the plurality of sets according to the reception timing of the plurality of long-period spreading codes detected by the timing detection unit, respectively. A code obtained by multiplying a subcarrier component, each long-period spreading code included in the long-period spreading code group, and the short-period spreading code. A second correlator for obtaining a correlation value with a sequence, and a plurality of long-period spreading code candidates for spreading the multicarrier signal according to each of the plurality of correlation values obtained by the second correlator A candidate code detection unit, a plurality of reception timing candidates detected by the timing detection unit, and a plurality of long period spread code candidates detected by the code candidate detection unit, Using the timing and code detection unit for detecting the long-period spreading code, the reception timing of the long-period spreading code detected by the timing and code detection unit, and the long-period spreading code, the signal receiving unit has received And a demodulation circuit that demodulates the data series from the multicarrier signal.
[0022]
A tenth feature of the present invention is that a data sequence obtained by multiplying a short-period spreading code and any one long-period spreading code included in a long-period spreading code group is transmitted using a plurality of subcarriers. A receiving apparatus in an MC-CDMA mobile communication system that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers with a synchronization signal spreading code. signal An FFT timing detection unit that detects a correlation between a reception unit, a guard interval portion of the multicarrier signal received by the signal reception unit and detects an FFT timing, and an FFT at the FFT timing detected by the FFT timing detection unit A correlation value between the subcarrier component including the synchronization signal and the synchronization signal replica among the plurality of subcarrier components separated by the subcarrier separation unit. A correlator to be obtained; and a timing detector for detecting a reception timing of the long-period spread code according to a correlation value obtained by the correlator.
[0023]
An eleventh feature of the present invention is that a data sequence obtained by multiplying a short-period spreading code and any one long-period spreading code included in the long-period spreading code group is transmitted using a plurality of subcarriers. A receiving apparatus in an MC-CDMA mobile communication system that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers with a synchronization signal spreading code. signal A receiving unit; an FFT timing detecting unit for detecting an FFT timing based on a correlation characteristic of a guard interval included in the multicarrier signal received by the signal receiving unit; and the FFT timing detected by the FFT timing detecting unit. A subcarrier separation unit that performs FFT in order to separate a plurality of subcarrier components, and among the plurality of subcarrier components separated by the subcarrier separation unit, a subcarrier component including the synchronization signal and a synchronization signal replica A first correlator for obtaining a correlation value, a timing detection unit for detecting a reception timing of the long-period spread code according to the correlation value obtained by the first correlator, and the timing detected by the timing detection unit The subcarrier separated by the subcarrier separation unit according to the reception timing of the long-period spreading code. A second correlator for obtaining a correlation value between a component and a code sequence obtained by multiplying each long-period spreading code and the short-period spreading code included in the long-period spreading code group; A code detection unit that detects a long-period spreading code that spreads the multicarrier signal according to the correlation value obtained by the correlator, and a reception timing of the long-period spreading code detected by the timing detection unit and the code A demodulation circuit that demodulates the data series from the multicarrier signal received by the signal reception unit using the long-period spreading code detected by the detection unit;
[0024]
A twelfth feature of the present invention is that a data series obtained by multiplying a short-period spreading code and any one long-period spreading code included in a long-period spreading code group is transmitted using a plurality of subcarriers. Receiving a reception signal including a plurality of subcarriers having a synchronization signal obtained by multiplying one or a plurality of subcarriers by only a synchronization signal spreading code; A correlation output step for outputting a correlation value between the received signal received in step and the synchronization signal replica, and an FFT timing and a reception timing of the long-period spread code according to the correlation value output in the correlation output step And a timing detection step for detecting.
[0025]
In the reception method in the mobile communication system described above, further, a separation step of performing FFT according to the FFT timing detected in the timing detection step and separating the received signal into a plurality of subcarrier components, and the timing detection Depending on the reception timing of the long-period spreading code detected in the step, the subcarrier component, each long-period spreading code included in the long-period spreading code group, and the short-period spreading code are multiply multiplied A correlation detection step of outputting a correlation detection value with the code sequence that has been multiplied; and a code detection step of detecting a long-period spread code that spreads the received signal in accordance with the correlation detection value output from the correlation detection step. It can have.
[0026]
A thirteenth feature of the present invention is that a data sequence obtained by multiplying a short-period spreading code and any one long-period spreading code included in a long-period spreading code group is transmitted using a plurality of subcarriers. Receiving a reception signal including a plurality of subcarriers having a synchronization signal obtained by multiplying one or a plurality of subcarriers by only a synchronization signal spreading code; A separation step of separating the received signal received in step into a plurality of subcarrier components, and a subcarrier component and a synchronization signal included in the synchronization signal among the plurality of subcarrier components separated in the separation step A correlation output step of outputting a correlation value with the replica, and a reception type of the long-period spreading code according to the correlation value output at the correlation output step Those having a timing detection step of detecting a ring.
[0027]
In the reception method in the mobile communication system, the separation step performs FFT according to a plurality of FFT timings, and the timing detection step uses the correlation values output in the correlation output step for all the FFT timings. In response, the target FFT timing and the reception timing of the long-period spreading code are detected, and further, the FFT is performed according to the FFT timing detected in the timing detection step, and the received signal is converted into a plurality of subcarrier components. And the subcarrier component, each long-period spreading code included in the long-period spreading code group, and the long-period spreading code according to the reception timing of the long-period spreading code detected in the timing detection step. Correlation detection value with a code sequence obtained by multiplying a short period spread code A correlation detecting step of force, according to the correlation detection value outputted from said correlation detecting step, can be made and a code detection step of detecting a long period spreading code for spreading the received signal.
[0028]
A fourteenth feature of the present invention is that a data sequence obtained by multiplying a short-period spreading code and any one long-period spreading code included in a long-period spreading code group is transmitted using a plurality of subcarriers. Receiving a reception signal including the plurality of subcarriers having a synchronization signal obtained by multiplying one or a plurality of subcarriers by only a synchronization signal spreading code; and The received signal received in step is subjected to FFT according to a plurality of FFT timings and separated into a plurality of subcarrier components, and among the plurality of subcarrier components separated in the separation step, A correlation output step for outputting a correlation value between the subcarrier component included in the synchronization signal and the synchronization signal replica, and output in the correlation output step. A timing detection step for detecting the reception timing of the long-period spreading code according to the correlation value, and the subcarrier component and the long-time according to the reception timing of the long-period spreading code detected at the timing detection step Correlation detection step for outputting a correlation detection value of a code sequence obtained by multiplying each long-period spreading code and the short-period spreading code included in the period spreading code group, and for all the FFT timings, A code detection step for detecting the FFT timing, the reception timing of the long-period spreading code, and the long-period spreading code for spreading the received signal according to the correlation detection value output from the correlation detection step It is.
[0029]
A fifteenth feature of the present invention is that a data sequence in which a short-period spreading code and any one long-period spreading code included in a long-period spreading code group are multiply multiplied is transmitted using a plurality of subcarriers. In the receiving method in the mobile communication system, the FFT timing detection step of detecting the correlation of the guard interval portion of the received signal and detecting the FFT timing, and the FFT timing obtained in the FFT timing detection step, perform FFT, and And a correlation output step of outputting a correlation value between a subcarrier component included in the synchronization signal and a synchronization signal replica among the plurality of subcarrier components separated in the separation step. And a reception type of the long-period spreading code according to the correlation value output in the correlation output step. Those having a timing detection step of detecting a ring.
[0030]
In the reception method in the mobile communication system, the subcarrier component and each of the lengths included in the long-period spreading code group according to the reception timing of the long-period spreading code detected in the timing detection step. A correlation detection step of outputting a correlation detection value of a code sequence obtained by multiplying a cycle spreading code and the short cycle spreading code, and the received signal according to the correlation detection value output from the correlation detection step And a code detection step of detecting a long-period spreading code for spreading the data.
[0031]
A sixteenth feature of the present invention is that a data sequence obtained by multiplying a short-period spreading code and any one long-period spreading code included in a long-period spreading code group is transmitted using a plurality of subcarriers. A receiving apparatus in an MC-CDMA mobile communication system that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers with a synchronization signal spreading code. signal A reception unit; and an FFT timing detection unit that detects a plurality of FFT timing candidates based on a correlation characteristic of a guard interval included in the multicarrier signal received by the signal reception unit, the FFT timing detection unit A multiplier that multiplies the multicarrier signal and a signal obtained by delaying the multicarrier signal by one symbol length, and an integrator that obtains a correlation value by integrating the multiplication value multiplied by the multiplier over a guard interval length. And a first memory for storing the correlation value obtained by the integrator and its timing, a second memory for storing a plurality of FFT timing candidates given in sequence, and the second memory. Searching each of the plurality of FFT timing candidates based on the plurality of FFT timing candidates and the stored value of the first memory A search range setting unit for setting a range, and first, a maximum correlation value and timing are selected from the stored values of the first memory, and stored in the second memory as the FFT timing candidate # 1, and then The search range setting unit is configured to set a search range based on the FFT timing candidates stored in the second memory and the stored value of the first memory, and the storage of the first memory within the search range Selects the maximum correlation value and timing from the values, stores them in the second memory as FFT timing candidates # 2, and repeats detection until a predetermined number of preset FFT timing candidates are detected in the same procedure And a circuit.
[0032]
In the reception apparatus in the MC-CDMA mobile communication system, the multicarrier signal is further subjected to FFT in each of the predetermined number of FFT timing candidates detected by the FFT timing detection unit, and a plurality of subcarriers are received. A correlation value between a subcarrier component including the synchronization signal and a synchronization signal replica among the plurality of subcarrier components separated by each of the plurality of subcarrier separation units separated into components and the plurality of subcarrier separation units is obtained. A plurality of first correlators, a plurality of timing detectors for detecting reception timing candidates of long-period spreading codes according to correlation values obtained by the plurality of first correlators, and the plurality of timing detections According to each reception timing candidate of the plurality of long-period spreading codes detected by each unit A plurality of second values for obtaining correlation values between the plurality of subcarrier components and a code sequence obtained by multiplying each of the long period spreading codes and the short period spreading codes included in the long period spreading code group. And a plurality of code candidate detections for detecting each of a plurality of long-period spread code candidates for spreading the multicarrier signal according to each of the plurality of correlation values obtained by each of the plurality of second correlators And a plurality of reception timing candidates detected by the plurality of timing detection units, and a plurality of long period spreading code candidates detected by the plurality of code candidate detection units, A timing and code detection unit for detecting the long-period spreading code, a reception timing of the long-period spreading code detected by the timing and code detection unit, and the long-period spreading code; Used, the data series from the multicarrier signal by the signal receiving unit receives can be provided with a demodulation circuit for demodulating.
[0033]
In the reception apparatus in the MC-CDMA mobile communication system, the multicarrier signal is further subjected to FFT in each of the predetermined number of FFT timing candidates detected by the FFT timing detection unit, and a plurality of subcarriers are received. A correlation value between a plurality of first FFT circuits that are separated into components and a subcarrier component that includes the synchronization signal and a synchronization signal replica among the plurality of subcarrier components separated by each of the plurality of first FFT circuits. A plurality of first correlators for obtaining the long-term spread code reception timing and FFT timing according to the correlation values obtained by the plurality of first correlators, and FFT is performed according to the FFT timing detected by the timing detector, and the multicarrier signal is transmitted. And a plurality of subcarrier components separated by the second FFT circuit in accordance with the reception timing of the long-period spreading code detected by the timing detection unit. A second correlator for obtaining a correlation value between a code sequence obtained by multiplying each long-period spreading code and the short-period spreading code included in the long-period spreading code group; and the second correlation A code detection unit that detects a long-period spreading code that spreads the multicarrier signal according to the correlation value obtained by the detector, a reception timing of the long-period spreading code detected by the timing detection unit, and the code detection unit And a demodulating circuit that demodulates the data sequence from the multicarrier signal received by the signal receiving unit using the long-period spreading code detected by.
[0034]
According to a seventeenth feature of the present invention, in a signal receiving method in a mobile communication system that transmits a code sequence using a plurality of subcarriers, the method includes a step of detecting a plurality of FFT timing candidates from a correlation characteristic of a guard interval. Is.
[0035]
According to an eighteenth feature of the present invention, in a signal receiving method in a mobile communication system that transmits a code sequence using a plurality of subcarriers, the received signal is multiplied by a signal obtained by delaying the received signal by one symbol length. A step of performing a moving average of the obtained multiplication values using the average interval as a guard interval length, a step of adding a correlation sequence of a plurality of correlation values obtained by the moving average in-phase for each guard interval insertion period, And detecting a plurality of FFT timing candidates from a correlation sequence having a length equal to the guard interval insertion period obtained by the addition.
[0036]
In the step of detecting a plurality of FFT timing candidates, the timing having the maximum correlation value is set as the first FFT timing candidate in the correlation sequence having a length equal to the guard interval insertion period obtained by the in-phase addition. Each of the second and subsequent FFT timing candidates, the timing having the maximum correlation value in the remaining correlation sequences obtained by excluding the peripheral W samples of each detected FFT timing candidate as an exclusion window is set to the next FFT. It is possible to have a step of detecting up to a predetermined number by repeating the method of timing candidates.
[0037]
According to a nineteenth feature of the present invention, in a signal receiving method in a mobile communication system that transmits a code sequence using a plurality of subcarriers, a step of detecting a plurality of FFT timing candidates from a correlation characteristic of a guard interval; Performing FFT on a plurality of FFT timing candidates and separating them into a plurality of subcarrier components, and outputting a correlation value between a subcarrier component including a synchronization signal and a synchronization signal replica among the plurality of separated subcarrier components A step of detecting one or more reception timing candidates for the long-period spreading code according to the output correlation value, and depending on the detected reception timing candidates for the one or more long-period spreading codes. Subcarrier component and each long-period spreading code and short-period spreading code included in the long-period spreading code group. A correlation detection value with the code sequence multiplied by the product, and for all detected FFT timing candidates, the FFT timing, the reception timing of the long-period spread code, and the reception signal are output according to the output correlation detection value. And a step of detecting a long-period spreading code to be spread.
[0038]
A twentieth feature of the present invention is that a data sequence obtained by multiplying a short-period spreading code and any one long-period spreading code included in a long-period spreading code group is transmitted using a plurality of subcarriers. In a signal reception method in a mobile communication system, a signal obtained by separating a received signal into subcarrier components by processing such as FFT, each long-period spreading code included in the long-period spreading code group, and the short-period spreading code, When a correlation detection value with a code sequence obtained by multiplying the two is multiplied, Navg symbols (Navg is an integer of 1 or more) are added in phase in the time direction to each subcarrier for each subcarrier. In-phase added values of Ncs subcarriers adjacent to each other in the frequency direction (Ncs is an integer satisfying 1 ≦ Ncs ≦ N, where N is the number of subcarriers), and the in-phase added value for each Ncs subcarrier is calculated in the frequency direction. Nps number (Nps is, 1 ≦ Nps ≦ N / Ncs becomes an integer) is used to detect the average correlation values by adding power.
[0039]
In the above-described signal reception method in the mobile communication system, when Nps <(N / Ncs), (N / Ncs) / Nps long-period spreading codes are alternately detected for each Ncs subcarrier in the frequency direction. Can be.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 shows a frame structure of a transmission signal used in an MC-CDMA mobile communication system. A scramble code, which is a long-period spreading code, has a different pattern for each base station in both the frequency direction and the time direction.
[0041]
FIG. 3 shows the configuration of the MC-CDMA transmission device 10.1 used in the mobile communication system according to the first embodiment of the present invention. The transmission device 10.1 is provided for each base station that transmits a radio signal. The transmission device 10.1 includes a plurality of data channel generation circuits 100.1 to 100. x. In each of the data channel generation circuits 100, the transmission data sequence input from the transmission data generation unit 101 is encoded by the transmission path encoder 102, and data modulation is performed by the data modulation unit 103. Then, pilot symbols are multiplexed on the modulated data sequence in multiplexing section 104, and serial / parallel conversion is performed in serial / parallel conversion section 105 to form N / SF information symbol sequences on the frequency axis. The N / SF information symbol sequences on the frequency axis subjected to serial / parallel conversion are copied by the copying unit 106 by the number of symbols SF equal to the sequence length of the short-period spreading code for each information symbol and arranged on the frequency axis. . Multipliers 108 multiply the arranged N information symbol sequences on the frequency axis by the short-period spreading code created by the short-period spreading code generator 107.
[0042]
The first combining unit 109 multiplexes the symbol sequence on the frequency axis of the sequence length N multiplied by each short period spreading code output from each data channel generation circuit 100. Each of the N multipliers 111 multiplies the multiplexed symbol sequence of sequence length N by the scramble code output from the scramble code generator 110 in the frequency direction, and outputs the result to the second synthesizer 112.1. Second synthesizing section 112.1 synthesizes the synchronization signal created in synchronization signal generating section 120.1 with the symbol sequence of sequence length N multiplied by the scramble code.
[0043]
An inverse Fourier transform device (IFFT) 113 converts N symbols into orthogonal multicarrier signals. The guard interval inserter 114 inserts a guard interval GI into this multicarrier signal. The transmitting device 10.1 then converts the multicarrier signal output from the guard interval inserter 114 into a radio signal and outputs it to the space.
[0044]
The synchronization signal is generated by the synchronization signal generator 120.1 as follows. The data generation unit 121 generates data for synchronization signals (usually data common to all base stations, all of which may be 1). The data modulation unit 121 modulates the synchronization signal data. The synchronization signal spreading code generator 123 generates a synchronization signal spreading code. The multiplier 124 multiplies the data signal modulated by the data modulation unit 121 and the synchronization signal spreading code output from the synchronization signal spreading code generator 123 to generate a synchronization signal to generate the second synthesis unit 112. Output to 1.
[0045]
Next, a method of transmitting a multicarrier signal by the MC-transmitting device 10.1 in FIG. 3 will be described. FIG. 4A illustrates an example in which the synchronization signal generation unit 120.1 transmits the synchronization signal continuously in the time direction on a plurality of specific subcarriers. FIG. 5B shows an example in which the synchronization signal generation unit 120.1 continuously transmits the synchronization signal in a specific subcarrier in the time direction. These synchronization signals S1 are signals obtained by multiplying the data signal D1 output from the data generator 121 by the synchronization signal spreading code C1 provided by the synchronization signal spreading code generator 123.
[0046]
The second synthesizing unit 112.1 in the transmission device 10.1 continuously uses the synchronization signal S1 generated by the synchronization signal generation unit 120.1 on the time axis in the corresponding specific subcarrier among the N subcarriers. Multiplex. Then, the IFFT circuit 113 performs inverse Fourier transform, and the guard interval inserter 114 inserts a symbol guard interval GI having a fixed length at every Fourier target time, and outputs it as a multicarrier signal.
[0047]
FIG. 5A also shows an example in which the synchronization signal is continuously transmitted in the time direction on one specific subcarrier. However, FIG. 5A shows an example in which the synchronization signal generator 120.1 generates the synchronization signal S2 in which the repetition time τ of one scramble code pattern is equal to the pattern length of the synchronization signal. The synchronization signal S2 indicates a data series having a specific pattern in the time direction. The specific pattern can be realized by a pattern of a scramble code for the synchronization signal. Therefore, in the receiving mobile station that receives the multicarrier signal transmitted by this transmission method, the reception timing of the multiplication start timing of the scramble code that is a long-period spreading code is detected by detecting the reception timing of the synchronization signal S2 from the received signal. Can be detected.
[0048]
FIG. 5B shows an example in which the length of the synchronization signal S3 is ½ of the repetition time τ of one scramble code pattern. Also in this case, the synchronization signal S3 is a sequence having a specific pattern in the time direction. Accordingly, the mobile station side can limit the reception timing of the scramble code multiplication start timing by detecting the transmission timing of the synchronization signal S3 from the received signal.
[0049]
The synchronization signal generated by the synchronization signal generation unit 120.1 is generated on the time axis in one or more specific subcarriers in the second synthesis unit 112.1 by the method shown in FIGS. Then, it is possible to multiplex in bursts. FIG. 6A shows an example in which the synchronization signal S4 is combined with a plurality of specific subcarriers and transmitted in bursts at the same timing. FIG. 6B shows an example in which the synchronization signal S4 is combined with one specific subcarrier and transmitted in bursts. FIG. 6C shows an example in which the synchronization signal S4 is combined with all subcarriers and transmitted in bursts at the same timing.
[0050]
FIGS. 7A and 7B are diagrams illustrating another method of transmitting the synchronization signal S5 used in the MC-CDMA transmission method. FIG. 7 (a) shows that the second synthesizing unit 112.1 changes the synchronization signal S5 having a constant pattern generated by the synchronization signal generating unit 120.1 to each of a plurality of specific subcarriers for each cycle of the scramble code. This is an example in which the synchronization signal S5 is multiplexed at the timing and transmitted in bursts. On the mobile station side that receives such a multicarrier signal, as shown in FIG. 7B, a plurality of subcarriers in which the synchronization signal S5 is transmitted from the reception signal and the reception timing of each synchronization signal S5 are determined. By detecting, the reception timing of the multiplication start timing of the scramble code can be detected.
[0051]
Next, the MC-CDMA transmission apparatus and transmission method according to the second embodiment of the present invention will be described. In the transmitting apparatus 10.2 shown in FIG. 8, elements that are the same as those of the transmitting apparatus shown in FIG. The feature of this embodiment is that the synchronization signal generation unit 120.1 includes a series-parallel conversion unit 125. In the synchronization signal generation unit 120.2, the data generation unit 121 generates a synchronization signal data series D1 (usually data common to all base stations, all of which may be 1). The synchronization signal data D1 is data-modulated by the data modulation unit 122, and further serial-parallel converted by the serial-parallel conversion unit 125, so as to obtain N symbol sequences P1 on the frequency axis. For each signal of the symbol series P1, the multiplier 126 is multiplied in the frequency direction by the synchronization signal spreading code C1 generated by the synchronization signal spreading code generator 123 to generate N parallel synchronization signals S6. To the second combining unit 112.2.
[0052]
The second synthesis unit 112.2 multiplexes the synchronization signal generated from the synchronization signal generation unit 120.2 at a specific timing. This multiplexing method is shown in FIGS. 9 (a) and 9 (b).
[0053]
The transmission methods shown in FIGS. 9A and 9B are methods in which the synchronization signal S6 is transmitted in bursts in all subcarriers. FIG. 9A shows a case where the start time of one scramble code pattern and the transmission timing of the synchronization signal S6 are made simultaneously. Therefore, the mobile station side can detect the reception timing of the scramble code multiplication start timing by detecting the reception timing of the synchronization signal S6 from the reception signal. FIG. 9B shows a case where the synchronization signal S6 is transmitted twice within the repetition time τ of one scramble code pattern. In this case, the transmission timing interval of the synchronization signal S6 is ½ of the scramble code pattern repetition time τ. Therefore, on the mobile station side, the reception timing of the multiplication start timing of the scramble code can be limited by detecting the reception timing of the synchronization signal S6 from the reception signal.
[0054]
Next, the configuration of receiving apparatus 20.1 in the MC-CDMA mobile communication system according to the third embodiment will be described with reference to FIG. 10, FIG. 11, and FIG. The scramble code reception timing detection circuit 200.1 in the receiving apparatus 20.1 has the internal configuration shown in FIG. 11, and receives the multicarrier signal received by the antenna 199, detects the scramble code reception timing and the FFT timing, and outputs them. To do. The guard interval removal circuit 208 removes the guard interval based on the FFT timing. The FFT 209 is a fast Fourier transform circuit, which decomposes the signal output from the GI removal circuit 208 into N subcarrier frequencies and outputs the result. The scramble identification circuit 210.1 has the internal configuration shown in FIG. 11, and identifies a scramble code from the received multicarrier signal. The demodulation circuit 300 has the internal configuration shown in FIG. 12, and demodulates the multicarrier signal received using the scramble code reception timing and the scramble code to obtain the original transmission data.
[0055]
A detailed configuration of the transmission device 20 will be described with reference to FIG. The scramble code reception timing detection circuit 200.1 inputs the multicarrier signal received by the antenna 199 to the correlator 201. On the other hand, the sync signal replica generator 202 generates a preset sync signal replica and sequentially inputs the sync signal replica to the correlator 201. The correlator 201 detects the correlation between the received multicarrier signal and the synchronization signal replica, and stores the correlation value indicating each peak obtained as a result and the timing thereof in the correlation value and timing memory 203. The timing detection circuit 204 selects the maximum correlation value and timing from the correlation value and the value stored in the timing memory 230 and stores them in the memory 205 as the scramble code reception timing. The timing detection circuit 204 further calculates the FFT timing from the scramble code reception timing and stores it in the memory 205 as the FFT timing. The FFT timing is output from the memory 205 to the GI removal circuit 208, and the scramble code reception timing is output to the scramble code identification circuit 210.1 and the demodulation circuit 300.
[0056]
After detection of the scramble code reception timing by the scramble code reception timing detection circuit 200.1, the GI removal circuit 208 removes the GI using the FFT timing output from the memory 205. The multicarrier signal from which the GI has been removed is input to the FFT circuit 209, separated into the original N subcarrier components, and input to the scramble code identification circuit 210.1.
[0057]
In the scramble code identification circuit 210.1, the scramble code replica generator 211 sets a plurality of types, for example, 512 types of phases set in advance by a predetermined calculation as the synchronization phase obtained from the scramble code reception timing detection circuit. To do. Correlators 212 corresponding to the number of subcarriers detect the correlation between the scramble code replica generated by the scramble code replica generator 211 and the output of the FFT circuit 209 for each subcarrier, and input the correlation detection value to the adder 213. . The adder 213 adds the correlation value in each subcarrier, and stores the correlation value and its scramble code number in the correlation value and code number memory 214.
[0058]
The scramble code detection circuit 215 calculates the maximum correlation value from the correlation value and the code number stored in the memory 214. as well as The code number is selected, and the identified scramble code number is output to the demodulation circuit 300.
Further, the detailed configuration of the demodulation circuit 300 will be described with reference to FIG. The received multicarrier signal is input to the circuit of FIG. The reception timing and number of the scramble code output from the circuit of FIG. 11 are input to the scramble code generator 301 to the demodulation circuit 300.
[0060]
On the other hand, the received multicarrier signal is also input to the FFT timing detection unit 302 of the demodulation circuit 300. Then, the FFT timing detection unit 302 detects the FFT timing of the multicarrier signal, and the guard interval remover (−GI) 303 removes the GI from the multicarrier signal. The FFT circuit 304 separates the multicarrier signal from which the guard interval has been removed into subcarrier components. After estimating the channel fluctuation value of each subcarrier, channel estimation section 305 compensates for the channel fluctuation by multiplier 306. A multiplier 307 multiplies the scramble code generated by the scramble code generator 301 in the subcarrier direction for each subcarrier symbol subjected to channel fluctuation compensation. Furthermore, a multiplier 308 multiplies the symbol multiplied by the scramble code with a corresponding short code in the subcarrier direction. The short code is provided by a short code generator 309. The combiner 310 combines and despreads SF symbols. The despread symbols are parallel-serial converted by a parallel-serial converter (P / S) 311 and further restored by a demodulator 312 and a decoder 313 to extract original data.
[0061]
A method for receiving a multicarrier signal by the receiving apparatus 20.1 in the MC-CDMA mobile communication system having the above configuration will be described next. FIG. 13 is a flowchart showing signal reception processing by the receiving device 20.1 of FIG. First, a correlation between a reception signal including all subcarrier components before performing FFT and a synchronization signal replica is detected (S101). The FFT timing, that is, the symbol timing and the scramble code reception timing are simultaneously obtained based on the timing for obtaining the maximum correlation value (S102).
[0062]
Subsequently, FFT is performed at the detected FFT timing to separate the received signal into subcarrier components (S103). Further, at the reception timing of the detected scramble code, the correlation between the received signal separated into each subcarrier component after FFT and each scramble code is detected (S104), and the scramble code having the maximum correlation value is received. The signal is detected as a scramble code for spreading (S105).
[0063]
The demodulating circuit 300 in the receiving device 20.1 performs descrambling on the multicarrier signal using the scramble code thus detected, and further demodulates and decodes the data signal to extract the original data series.
[0064]
Next, a receiving apparatus in the MC-CDMA mobile communication system according to the fourth embodiment of the present invention will be described with reference to FIG. The receiving device 20.2 of the fourth embodiment has the same functional block configuration as the receiving device 20.1 shown in FIG. 10, but the configuration of the scramble code reception timing detection circuit and the scramble code identification circuit is the same. Is different. This will be described.
[0065]
The scramble code reception timing detection circuit 200.2 receives a multicarrier signal, and a plurality of synchronization signal correlation detection circuits 2011.1 to 2010. Input to m. On the other hand, in the FFT timing setting circuit 2014, each synchronization signal correlation detection circuit 2010. An FFT timing is set for x (x = 1, 2,..., m). Each synchronization signal correlation detection circuit 2010. In x, the guard interval removal circuit 2015 removes the GI from the multicarrier signal using the FFT timing. The multicarrier signal from which the GI has been removed is input to the FFT circuit 2016 and is separated into a plurality of subcarrier components by the FFT circuit 2016. Of the separated subcarrier components, only the subcarrier component on which the synchronization channel is multiplexed is input to the correlator 2012. On the other hand, the synchronization signal replica generator 2013 generates a synchronization signal replica and inputs it to the correlator 2012. Correlator 2012 detects the correlation between the FFT output and the synchronization signal replica, and inputs the correlation value in each subcarrier to adder 207. Adder 207 adds the correlation values in each subcarrier, and stores the correlation values and their timings in memory 203.
[0066]
The timing detection circuit 204 selects the maximum correlation value and timing from the m correlation values and the stored value in the timing memory 203 and stores them in the memory 205 as the scramble code reception timing. The timing detection circuit 204 further calculates the FFT timing from the scramble code reception timing and stores it in the memory 205 as the FFT timing. The FFT timing is output from the memory 205 to the GI removal circuit 208, and the scramble code reception timing is output to the scramble code identification circuit 210.1 and the demodulation circuit 300.
[0067]
After detection of the scramble code reception timing by the scramble code reception timing detection circuit 200.2, the GI removal circuit 208 removes the GI, the FFT circuit 209 performs the FFT, and the scramble code identification circuit 210.1 specifies the scramble code number. Then, the processing to output to the demodulation circuit 300 is performed by the same circuit as in FIG. Further, the data demodulation processing by the demodulation circuit 300 is performed by the same circuit as in FIG.
[0068]
Next, a method of receiving a multicarrier signal by the receiving apparatus 20.2 having the above configuration will be described. FIG. 15 is a flowchart showing multicarrier signal reception processing by the receiving device 20.2 shown in FIGS. An FFT is performed at a certain FFT timing (S2011. 1), and a correlation between a subcarrier component transmitting a synchronization signal and a synchronization signal replica is detected for a signal after the FFT at a certain FFT timing (S2012. 1). This is performed at a plurality of FFT timings (S201.1 to S201.m). Of the correlation values detected at all the FFT timings, the reception timing of the scramble code is obtained at the timing at which the maximum correlation value is obtained. Further, the FFT timing is detected based on the FFT timing at which the maximum correlation value is detected (S202).
[0069]
Next, FFT is performed at the detected FFT timing (S203), and the received signal is separated into subcarrier components. At the reception timing of the detected scramble code, the correlation between the received signal separated into each subcarrier component after FFT and each scramble code is detected (S204), and the scramble code having the maximum correlation value is converted to the received signal. It is detected as a spreading scramble code (S205).
[0070]
Subsequently, the demodulation circuit 300 in the receiving device 20.2 performs descrambling on the multicarrier signal using the scramble code thus detected, and further demodulates and decodes the data signal to extract the original data series.
[0071]
Next, a receiving apparatus according to a fifth embodiment of the present invention will be described with reference to FIGS. The receiving device 20.3 according to the fourth embodiment includes a scramble code reception timing detection circuit 200.3, a scramble code identification circuit 210.1, and a demodulation circuit 300.
[0072]
A scramble code reception timing detection circuit 200.3 receives a multicarrier signal and separates it into subcarrier components using a DFT circuit or the like 2011. Of the separated subcarrier components, only the subcarrier component on which the synchronization channel is multiplexed is input to the correlator 2012. On the other hand, the synchronization signal replica generator 2013 generates a synchronization signal replica and inputs it to the correlator 2012. Correlator 2012 detects the correlation between each of the subcarrier components from DFT circuit 2011 and the synchronization signal replica, and inputs the correlation value in each subcarrier to adder 207. The adder 207 adds the correlation value in each subcarrier, and stores the correlation value and its timing in the memory 203 of the correlation value and timing. The timing detection circuit 204 selects the maximum correlation value and timing from the correlation value and the value stored in the timing memory 230 and stores them in the memory 205 as the scramble code reception timing. The scramble code reception timing is output from the memory 205 to the scramble code identification circuit 210.1.
[0073]
The configuration of the scramble identification circuit 210.1 is the same as that of FIG. The scramble code replica generator 211 sets a plurality of types of phases set in advance by a predetermined calculation to the synchronization phase obtained from the scramble code reception timing detection circuit 200.3. Correlators 212 corresponding to the number of subcarriers detect the correlation between the scramble code replica generated by the scramble code replica generator 211 and the output of the DFT circuit 2011 for each subcarrier, and input the correlation detection value to the adder 213. . The adder 213 adds the correlation value in each subcarrier, and stores the correlation value and its scramble code number in the correlation value and code number memory 214. The scramble code detection circuit 215 selects the maximum correlation value and code number from the correlation value and the code number stored in the memory 214, and outputs the identified scramble code number to the demodulation circuit 300. The data demodulation processing by the demodulation circuit 300 is based on the above-described circuit of FIG.
[0074]
A method for receiving a multicarrier signal by the receiving apparatus 20.3 in the MC-CDMA mobile communication system having the above configuration will be described next. FIG. 17 is a flowchart showing a multicarrier signal reception method by the reception device 20.3. First, a received signal is separated into subcarrier components using a DFT (Discrete Fourier Transform) circuit or the like (S301). Among the received signals separated into the subcarrier components, the correlation between the subcarrier component transmitting the synchronization signal and the synchronization signal is detected (S302), and the reception timing of the scramble code is determined by the timing to obtain the maximum correlation value. Obtain (S303).
[0075]
Next, at the reception timing of the detected scramble code, the correlation between the received signal separated into each subcarrier component and each scramble code is detected (S304), and the scramble code having the maximum correlation value is converted to the received signal. It is detected as a spreading scramble code (S305).
[0076]
The demodulating circuit 300 in the receiving device 20.3 performs descrambling on the multicarrier signal using the scramble code thus detected, and further demodulates and decodes the data signal to extract the original data series.
[0077]
Next, a multicarrier signal receiver according to a sixth embodiment of the present invention will be described with reference to FIGS. 18 and 12. FIG. The receiving apparatus 20.4 includes m scramble code correlation detection circuits 230.1 to 230. m, an FFT timing setting circuit 2014 for setting FFT timings for them, a scramble code and scramble code reception timing detection circuit 240, and a demodulation circuit 300 shown in FIG. Each scramble correlation detection circuit 230. x includes a GI removal circuit 205, an FFT circuit 2016, a scramble code reception timing detection circuit 200.3 similar to that provided in FIG. 16, and a scramble code identification circuit 210.2.
[0078]
Each scramble code correlation detection circuit 230. x inputs a multicarrier signal received by the antenna 199. On the other hand, the FFT timing setting circuit 2014 includes each scramble code correlation detection circuit 230. The FFT timing is set for the GI removal circuit 2015 for x. The GI removal circuit 2015 removes the GI using the set FFT timing. The multicarrier signal from which the GI has been removed is input to the FFT circuit 2016, separated into subcarrier components, and only the subcarrier components are input to the correlator 2012. On the other hand, the synchronization signal replica generator 2013 generates a synchronization signal replica and inputs it to the correlator 2012. Correlator 2012 detects the correlation between each of the subcarrier components from FFT circuit 2016 and the synchronization signal replica, and inputs the correlation value in each subcarrier to adder 207. The adder 207 adds the correlation value in each subcarrier, and stores the correlation value and its timing in the memory 203 of the correlation value and timing.
[0079]
The timing detection circuit 204 selects the maximum correlation value and timing from the correlation value and timing stored in the memory 203 and stores them in the memory 205 as scramble code reception timing candidates.
[0080]
After the scramble code reception timing is detected, the scramble code identification circuit 210.2 sets the phase of the scramble code replica generator 211 to the synchronization phase obtained from the scramble code reception timing detection circuit 200.3. Correlator 212 detects the correlation between the scramble code replica generated by scramble code replica generator 211 and the output of FFT circuit 2016 for each subcarrier, and inputs the correlation detection value to adder 213. The adder 213 adds the correlation value in each subcarrier, and stores the correlation value and its scramble code number in the correlation value and code number memory 214.
[0081]
The scramble code and scramble code reception timing detection circuit 240 selects the maximum correlation value and code number from the correlation value stored in each scramble code identification circuit 210.2 and the code number stored in the memory 214. The scramble code reception timing is selected from the value stored in the memory 205 in the scramble code reception timing detection circuit 200.3 when the maximum correlation value is detected. The selected scramble code number and scramble code reception timing are output to the demodulation circuit 300.
[0082]
A method for receiving a multicarrier signal by the receiving apparatus 20.4 in the MC-CDMA mobile communication system having the above configuration will be described next. FIG. 19 is a flowchart showing a multicarrier signal reception method by the reception device 20.4. The FFT is performed at a certain FFT timing (S4011.1), and the correlation between the subcarrier component transmitting the synchronization signal and the synchronization signal is detected for the signal after the FFT at a certain FFT timing (S4012.1). The timing for obtaining the maximum correlation value at each FFT timing is detected, and this is used as a scramble code reception timing candidate at the FFT timing (S4013.1). Then, at this scramble code reception timing, the correlation between the received signal separated into each subcarrier component and each scramble code is detected (S4014.1). This is performed at a plurality of FFT timings (S401.1 to S401.n).
[0083]
Subsequently, the scramble code having the maximum correlation value and its timing are detected from the scramble code correlation values detected at all FFT timings and the reception timing thereof (S402). Using the scramble code thus detected, the demodulator circuit 300 descrambles the multicarrier signal, and further demodulates and decodes the data signal to extract the original data series.
[0084]
Next, a receiving apparatus used for the MC-CDMA transmission system according to the seventh embodiment of the present invention will be described with reference to FIG. 20 and FIG. The receiving apparatus 20.5 of this embodiment includes an FFT timing detection circuit 250.1, a GI removal circuit 2015, an FFT circuit 2016, a scramble code reception timing detection circuit 200.3 similar to that shown in FIG. 14 includes a scramble code identification circuit 210.1 similar to that shown in FIG. 14 and a demodulation circuit 300 shown in FIG.
[0085]
The receiving device 20.5 inputs the multicarrier signal received by the antenna 199 to the FFT timing detection circuit 250.1, the GI removal circuit 2015, and the demodulation circuit 300, respectively. In the FFT timing detection circuit 250.1, the received multicarrier signal is delayed by one symbol length (excluding GI) by the delay circuit 251. Multiplier 252 multiplies the received multicarrier signal by a signal obtained by delaying the signal by one symbol length (excluding GI). The multiplied signal is integrated by the integrator 253 over the GI length, and the correlation value is detected. The detected correlation value and its timing are stored in the correlation value and timing memory 254. The timing detection circuit 255 selects the maximum correlation value and timing from the correlation value and the stored value in the timing memory 254, and stores them in the memory 256 as the FFT timing.
[0086]
After detecting the FFT timing, the GI removal circuit 2015 removes the GI from the multicarrier signal using the FFT timing output from the memory 256. The multicarrier signal from which the GI has been removed is input to the FFT circuit 2016 and separated into subcarrier components.
[0087]
Of the signals separated into the subcarrier components, only the subcarrier component on which the synchronization channel is multiplexed is input to each correlator 2012 of the scramble code reception timing detection circuit 200.3. The processing in the scramble code reception timing detection circuit 200.3 is the same as that in FIG. The detected scramble code reception timing is stored in the memory 205.
[0088]
After detecting the scramble code reception timing, the scramble code identification circuit 210.1 specifies the scramble code number. The processing by the scramble code identification circuit 210.1 is the same as that in FIG. The scramble code number output from the scramble code detection circuit 215 is input to the demodulation circuit 300.
[0089]
The demodulating circuit 300 is shown in FIG. 12, and as described above, the scramble code number is used to descramble the multicarrier signal, and the data signal is demodulated and decoded to extract the original data series.
[0090]
Next, a method of receiving a multicarrier signal by the receiving apparatus 20.5 in the MC-CDMA mobile communication system having the above configuration will be described. FIG. 21 is a flowchart showing a multicarrier signal reception method by the reception device 20.5. First, a correlation between a reception signal including all subcarrier components before performing FFT and a signal obtained by delaying the reception signal by one symbol length (excluding the guard interval) is detected (S501). The FFT timing is obtained from the timing for obtaining the maximum correlation value (S502).
[0091]
Next, FFT is performed at the detected FFT timing, and the received signal is separated into subcarrier components (S503). Among the received signals separated into the subcarrier components, the correlation between the subcarrier component transmitting the synchronization signal and the synchronization signal is detected (S504), and the reception timing of the scramble code is determined by the timing for obtaining the maximum correlation value. Obtain (S505). Subsequently, a scramble code for spreading the received signal is detected by the same method as steps S304 and S305 in the flowchart of FIG.
[0092]
Using the scramble code thus obtained, the demodulating circuit 300 performs descrambling on the multicarrier signal, and further demodulates and decodes the data signal to extract the original data series, as in the other embodiments. .
[0093]
Next, a reception apparatus in the MC-CDMA mobile communication system according to the eighth embodiment of the present invention will be described. The MC-CDMA signal reception technique shown in the circuit of FIG. 20 and the flowchart of FIG. 21 detects one FFT timing from the timing at which the maximum correlation value is obtained using the correlation characteristics of the guard interval.
[0094]
However, in a MC-CDMA mobile communication system, in a situation where signals are simultaneously transmitted from a plurality of base stations and received simultaneously by one mobile station, if there is a variation in the total transmission power between the base stations, the mobile station A station may erroneously detect a signal of a base station having a large total transmission power as a normal signal, not a signal from an optimal base station having a small attenuation of a received signal. An example of the above problem is as follows.
[0095]
The flowchart of FIG. 22 shows the correlation detection processing procedure of the guard interval portion by the receiving apparatus of FIG. 20, and FIG. 23 shows the principle of the method. Here, the FFT timing is a timing at which the head of an information symbol not including a guard interval is received, and is a timing at which FFT processing is to be performed. Therefore, in the following description, all FFT timings are FFT timings. Further, it is assumed that 1 symbol length = X samples and guard interval length = Y samples.
[0096]
In the flowchart of FIG. 22 and the reception method shown in FIG. 23, a reception signal including all subcarrier components before FFT and a signal obtained by delaying the reception signal by one symbol (X sample) length are multiplied at each sample timing ( Step S1001). Then, the multiplication value for each sample timing is moving averaged for each sample, with each sample timing as the head of the average interval and the average interval length as the Y sample length (step S1002). A series of correlation values obtained by moving average is averaged a plurality of times by in-phase addition for each (X + Y) sample to obtain a correlation series of (X + Y) sample length (step S1003). FIG. 24 shows an example of this correlation sequence. Subsequently, the timing for obtaining the maximum correlation value in the correlation sequence of (X + Y) sample length as shown in FIG. 24 is detected as the FFT timing (step S1004).
[0097]
However, the magnitude of the correlation peak as in the correlation sequence shown in FIG. 24 depends not only on the attenuation amount of the received signal (path loss due to distance attenuation or shadowing) but also on the total transmission power of each base station. Therefore, when the above-described method is used in an MC-CDMA mobile communication system, the reception level per channel (minimum path loss is minimized) in a situation where the total transmission power of each base station varies in a multi-cell environment. There is a risk of erroneously detecting a base station with a high power of the transmitting communication channel instead of the optimal base station. For example, when the number of communication channels of the base station # 1 is significantly smaller than the number of communication channels of the base station # 2 between the base stations # 1 and # 2, the optimal base station for the mobile station is the base station # 1 However, base station # 2 having a large number of communication channels and thus a large total transmission power may be erroneously detected.
[0098]
FIG. 25 shows a receiver in an MC-CDMA mobile communication system that solves this problem. 25 includes an FFT timing detection circuit 250.2 and scramble code correlation detection circuits 230.1 to 230. m, a scramble code and scramble code reception timing detection circuit 240, and the same demodulation circuit 300 as shown in FIG.
[0099]
The FFT timing detection circuit 250.2 delays the received multicarrier signal by one symbol length (excluding GI) by the delay circuit 251. Multiplier 252 multiplies the received multicarrier signal by a signal obtained by delaying the signal by one symbol length (excluding GI). The multiplied signal is integrated by the integrator 253 over the GI length, and the correlation value is detected. The detected correlation value and its timing are stored in the correlation value and timing memory 254.
[0100]
First, the timing detection circuit 255 selects the maximum correlation value and timing from the correlation value and the stored value in the timing memory 254, and stores them in the memory 256 as the FFT timing candidate # 1. Next, the search range setting circuit 257 sets a search range based on the detected FFT timing candidates and correlation values in the memory 256 and the stored values in the timing memory 254. Various methods described later are used for setting the search range. In the timing detection circuit 255, the maximum correlation value and timing are selected from the correlation value and the value stored in the timing memory 254 within the search range set by the search range setting circuit 257, and the memory 256 is used as the FFT timing candidate # 2. To remember. In the same procedure, the detection is continued until a plurality of preset FFT timing candidates are detected.
[0101]
The scramble code correlation detection circuits 230.1 to 230m are prepared for m FFT timing candidates detected by the FFT timing detection circuit 250.2. Each scramble code correlation detection circuit 230. The configuration of x (x = 1 to m) is the same as that shown in FIG. 18, and includes a GI removal circuit 2015, an FFT circuit 2016, a scramble code reception timing detection circuit 200.3, and a scramble code identification circuit 210.2. ing.
[0102]
Each scramble code correlation detection circuit 230. x inputs the multicarrier signal received by the antenna 199 to the GI removal circuit 2015. On the other hand, the FFT timing detection circuit 250.1 includes each scramble code correlation detection circuit 230. The FFT timing is set for the GI removal circuit 2015 for x.
[0103]
The GI removal circuit 2015 removes the GI using the set FFT timing. The multicarrier signal from which the GI has been removed is input to the FFT circuit 2016, separated into subcarrier components, and only the subcarrier components are input to the correlator 2012. On the other hand, the synchronization signal replica generator 2013 generates a synchronization signal replica and inputs it to the correlator 2012. Correlator 2012 detects the correlation between each of the subcarrier components from FFT circuit 2016 and the synchronization signal replica, and inputs the correlation value in each subcarrier to adder 207. The adder 207 adds the correlation value in each subcarrier, and stores the correlation value and its timing in the memory 203 of the correlation value and timing. The timing detection circuit 204 selects the maximum correlation value and timing from the correlation value and timing stored in the memory 203 and stores them in the memory 205 as scramble code reception timing candidates. Therefore, the m scramble code correlation detection circuits 230.1 to 230. m scramble code reception timing candidates are obtained from m.
[0104]
After detection of each scramble code reception timing candidate, the scramble code identification circuit 210.2 obtains a scramble code number and a correlation value corresponding to each scramble code reception timing candidate.
[0105]
The scramble code and scramble code reception timing detection circuit 240 selects the maximum correlation value and code number from the correlation value of each scramble code identification circuit 210.2 and the stored value of the code number in the memory 214. When the maximum correlation value is detected, a scramble code reception timing candidate is selected from the stored value of the memory 205 in the corresponding scramble code reception timing detection circuit 200.3 and set as a scramble code reception timing. The selected scramble code number and scramble code reception timing are output to the demodulation circuit 300.
[0106]
The demodulating circuit 300 is shown in FIG. 12, and as described above, the scramble code number is used to descramble the multicarrier signal, and the data signal is demodulated and decoded to extract the original data series.
[0107]
A method of detecting a predetermined number of FFT timing candidates from the received multicarrier signal by the FFT timing detection circuit 250.2 in the receiving apparatus 20.6 having the above configuration will be described with reference to the flowchart of FIG.
[0108]
The received multicarrier signal including all subcarrier components before FFT and the signal obtained by delaying the received multicarrier signal by one symbol (X sample) length are multiplied at each sample timing (step S1101). Then, the multiplication value for each sample timing is moving averaged for each sample, with each sample timing as the head of the average interval and the average interval length as the Y sample length (step S1102). A series of correlation values obtained by moving average is averaged a plurality of times by in-phase addition for each (X + Y) sample to obtain a correlation series of (X + Y) sample length (step S1103). The processes of S1101 to S1103 are the same as the processes of S1001 to S1003 in the flowchart of FIG.
[0109]
Subsequently, a plurality of FFT timing candidates are detected from the (X + Y) sample length correlation sequence as shown in FIG. 24 (steps S1104 to S1106). FIG. 27 shows a case where three FFT timing candidates are detected. This is detected as follows. First, let the timing at which the maximum correlation output is detected in the (X + Y) sample length correlation sequence be FFT timing candidate # 1. Next, the preset W samples around the FFT timing candidate # 1 are excluded from the search range as an exclusion window # 1, and the timing at which the maximum correlation output is detected in the correlation sequence of (X + Y−W) sample length is the FFT timing. Candidate # 2. Similarly, peripheral W samples of FFT timing candidate # 2 are further excluded from the search range as exclusion window # 2, and FFT timing candidate # 3 is detected.
[0110]
By using the above method, even when the total transmission power of each base station varies in a multi-cell environment, it is possible to detect without missing a base station with a small total transmission power.
[0111]
Using the predetermined number m of FFT timing candidates detected in this way, next, a scramble code is identified by the flowchart shown in FIG. The process shown in FIG. 28 is an example when the number of scramble code reception timing candidates to be detected is equal to the number m of FFT window timing candidates.
[0112]
The process S1100 for detecting a plurality of m FFT timing candidates shows the entire process shown in the flowchart of FIG.
[0113]
Following this, FFT is performed on the detected plurality of FFT timing candidates, and the correlation between the subcarrier component transmitting the synchronization signal and the synchronization signal is detected for the signal after each FFT (steps S1201.1 and S1202). .1). The timing at which the maximum correlation value is detected in each FFT timing candidate is set as a scramble code reception timing candidate at that FFT timing, and the received signal and each scramble code separated into each subcarrier component in the scramble code reception timing candidate Is detected (steps S1203.1 and S1204.1). The processing of steps S1201.1 to S1204.1 is performed for all the plurality of m FFT timing candidates (S1200.1 to S1200.m).
[0114]
Next, among the scramble code correlation values detected in all FFT timing candidates, a scramble code that spreads the received signal, its reception timing, and FFT timing are detected from the scramble code having the maximum correlation value and its timing (S1300). ). That is, the FFT timing and scramble code reception timing are determined at the same time as the type of scramble code in step S1300.
[0115]
The method of detecting a plurality of m FFT timing candidates performed by the FFT timing detection circuit 250.2 in the receiving apparatus of FIG. 25 may be as shown in FIG. 29 or FIG. FIG. 29 shows a case where the exclusion windows # 1 and # 2 do not overlap. After the detection of the FFT timing candidate # 1, the W sample is set as the exclusion window # 1 for W / 2 samples before and after the FFT timing candidate # 1. W samples are excluded from the search range, and the timing at which the maximum correlation output is detected in the correlation sequence of (X + Y−W) sample length is defined as FFT timing candidate # 2. Similarly, the peripheral W samples of the FFT timing candidate # 2 are excluded from the search range as an exclusion window # 2, and the FFT timing candidate # 3 is detected.
[0116]
FIG. 30 shows a case where the exclusion window # 1 and the exclusion window # 2 overlap. In the same manner as in FIG. 29, detection is performed up to FFT timing candidate # 2. The peripheral W samples of the FFT timing candidate # 2 are excluded from the search range as an exclusion window # 2, but because there are portions where the exclusion windows # 1 and # 2 overlap, the number of samples excluded from the search range is less than 2W samples Become.
[0117]
Next, another method for determining a plurality of FFT timing candidates will be described with reference to FIG. In the case of detecting three FFT timing candidates (m = 3), after detecting FFT timing candidate # 1, W samples up to the timing having the correlation value of ΔdB reduction of the correlation value in FFT timing candidate # 1 are excluded window # Set as 1. Then, the W sample exclusion window is excluded from the search range, and the timing at which the maximum correlation output is detected in the (X + Y−W) sample length correlation sequence is defined as FFT timing candidate # 2. In the same procedure, the W ′ samples up to the timing having the correlation value of ΔdB reduction of the correlation value in the FFT timing candidate # 2 are set as the exclusion window # 2, the W ′ samples are further excluded from the search range, and the FFT timing candidate # 3 is detected.
[0118]
Next, still another method for determining a plurality of FFT timing candidates will be described with reference to FIGS. 32 and 33. Also in this case, an example is shown in which three (m = 3) FFT timing candidates are detected. FIG. 32 shows a case where the window width is changed depending on the magnitude of the slope of the correlation sequence having the vertex at the FFT timing. When the slope of the correlation peak is steep, the exclusion window is narrowed, and when the slope is gentle, the exclusion window is widened. Set. That is, when the peak width is narrow, the width is narrowed as shown in the exclusion window # 1, and when the peak width is wide, the width is set wide as shown in the exclusion window # 2.
[0119]
FIG. 33 shows an example in which an exclusion window is set while the correlation value continues to decrease as the distance from the detected FFT timing (the peak of the correlation peak) increases. In this case, after detecting FFT timing candidate # 1, W samples whose correlation values continue to decrease as they move away from FFT timing candidate # 1 are excluded from the search range as exclusion window # 1. Then, the timing at which the maximum correlation output is detected in the (X + Y−W) sample length correlation sequence is set as FFT timing candidate # 2. In the same procedure, W ′ samples whose correlation values continue to decrease as they move away from this FFT timing candidate # 2 are also excluded from the search range as an exclusion window # 2, and the next FFT timing candidate # 3 is detected.
[0120]
32 and 33, the exclusion window can be set adaptively even when the correlation peaks overlap or the peak width changes due to the influence of multipath.
[0121]
Next, another method for determining a plurality of FFT timing candidates will be described with reference to FIGS. 34 and 35. FIG. FIG. 34 shows the above FIG. FIG. This shows a method of detecting two FFT timing candidates by any one of the methods and adding eight new FFT timing candidates. First, two FFT timing candidates # 1 and # 2 are detected by the above method. Then, the timings of ± A samples and ± 2A samples of FFT timing candidates # 1 and # 2 are also set as FFT timing candidates.
[0122]
FIG. 35 shows the above FIG. FIG. This shows a method of detecting two FFT timing candidates by any one of the methods and adding four new FFT timing candidates. First, two FFT timing candidates # 1 and # 2 are detected by the above method. And the timing which has the correlation value of (DELTA) dB reduction | decrease of the correlation value in FFT timing candidate # 1, # 2 is set as a FFT timing candidate.
[0123]
According to the above method, even if the correlation peaks overlap and the timing is detected with a large shift from the ideal timing, or when it is detected with a shift due to the influence of noise or interference, the shift amount is kept small. It is possible to detect the FFT timing with higher accuracy.
[0124]
Note that, even if a plurality of m FFT timing candidates are detected by any of these methods, the process of detecting the scramble code number and the reception timing using the FFT timing candidates is performed by the process S1200 in FIG. According to S1300.
[0125]
Next, a receiving apparatus in the MC-CDMA mobile communication system according to the ninth embodiment of the present invention will be described with reference to FIG. The receiving apparatus 20.7 of this embodiment includes an FFT timing detection circuit 250.2 similar to that used in the receiving apparatus 20.6 of FIG. 25, the receiving apparatus 20. scramble code reception timing detection circuit 200.2, GI removal circuit 208, FFT circuit 209 and scramble identification circuit 210.1 similar to those used in x, and the same demodulation circuit 300 as shown in FIG. The
[0126]
The FFT timing detection circuit 250.2 detects a plurality of m FFT timing candidates from the received multicarrier signal by the same processing as in FIG.
[0127]
As in FIG. 14, the scramble code reception timing detection circuit 200.2 includes a GI removal circuit 2015, an FFT circuit 2016, and m synchronization signal correlation detection circuits 2011-2010. m, a timing detection circuit 204, and a memory 205.
[0128]
The scramble code reception timing detection circuit 200.2 receives a multicarrier signal, and a plurality of m synchronization signal correlation detection circuits 2011.about.2010. Input to m. On the other hand, the FFT timing detection circuit 250.2 includes each synchronization signal correlation detection circuit 2010. FFT timing candidates are set for x (x = 1, 2,..., m).
[0129]
Each synchronization signal correlation detection circuit 2010. In x, the guard interval removal circuit 2015 removes the GI from the multicarrier signal using each FFT timing candidate. The multicarrier signal from which the GI has been removed is input to the FFT circuit 2016, and is separated into a plurality of subcarrier components in which the synchronization channel is multiplexed by the FFT circuit 2016. Of the separated subcarrier components, only the subcarrier component on which the synchronization channel is multiplexed is input to the correlator 2012. On the other hand, the synchronization signal replica generator 2013 generates a synchronization signal replica and inputs it to the correlator 2012. Correlator 2012 detects the correlation between the FFT output and the synchronization signal replica, and inputs the correlation value in each subcarrier to adder 207. The adder 207 adds the correlation value in each subcarrier, and stores the correlation value and its timing in the correlation value and timing memory 203.
[0130]
The timing detection circuit 204 selects the maximum correlation value and timing from the m correlation values and the stored value in the timing memory 203 and stores them in the memory 205 as the scramble code reception timing. The timing detection circuit 204 further calculates the FFT timing from the scramble code reception timing and stores it in the memory 205 as the FFT timing. The FFT timing is output from the memory 205 to the GI removal circuit 208, and the scramble code reception timing is output to the scramble code identification circuit 210.1 and the demodulation circuit 300.
[0131]
After detection of the scramble code reception timing by the scramble code reception timing detection circuit 200.2, the GI removal circuit 208 removes the GI, the FFT circuit 209 performs the FFT, and the scramble code identification circuit 210.1 specifies the scramble code number. Then, the processing to output to the demodulation circuit 300 is performed by the same circuit as in FIG. Further, the demodulator circuit 300 is shown in FIG. 12, performs descrambling on the multicarrier signal using the scramble code number as described above, and further demodulates and decodes the data signal to extract the original data series.
[0132]
The detection method of the scramble code number and timing by the receiving apparatus 20.7 having the above configuration is based on the flowchart of FIG. First, the FFT timing detection circuit 250.2 detects a predetermined number m of FFT timing candidates from the received multicarrier signal (S1100). This process is performed according to the flowchart of FIG. 26 as in the eighth embodiment. The detection of a plurality of FFT timing candidates may be performed by any of the methods shown in FIGS.
[0133]
Next, FFT is performed on a plurality of detected FFT timing candidates, and the correlation between the subcarrier component transmitting the synchronization signal and the synchronization signal is detected for the signal after each FFT (S1401.1, S1402.1). . This is performed for all FFT timing candidates (S1400.1 to S1400.m).
[0134]
Subsequently, of the correlation values in all FFT timing candidates, the timing at which the maximum correlation value is detected and the FFT timing at that time are used as the reception timing of the scramble code for spreading the reception signal and the FFT timing of the reception signal ( Step S1500). Next, at the detected scramble code reception timing, the correlation between the received signal separated into each subcarrier component and each scramble code is detected (step S1600). Then, a scramble code for spreading the received signal is detected from the scramble code having the maximum correlation value (step S1700).
[0135]
In the method shown in the flowchart of FIG. 37, the FFT timing and the reception timing of the scramble code are determined in step S1500 before the scramble code type is detected.
[0136]
Next, a method for detecting correlation of scramble codes will be described. However, N subcarrier frequencies are assumed to be # 1 to #N. The example (tenth embodiment) shown in FIG. 38 is an example in the case of Navg = 6, Ncs = 4, Nps = N / Ncs. The correlation value of each symbol is added in the Navg symbol in-phase in the time direction for each subcarrier. Then, the in-phase addition value for each subcarrier is in-phase added over Ncs subcarriers. Subsequently, Nps powers are added to the in-phase added value for each Ncs subcarrier in the frequency direction to obtain a correlation value of each scramble code.
[0137]
When Nps = N / Ncs as in this example, correlation values for one scramble code are detected using N subcarriers × Navg symbols.
[0138]
The example (eleventh embodiment) shown in FIG. 39 is an example in the case of Navg = 6, Ncs = 4, and Nps = 1. In this case, since Nps = 1, the in-phase addition value of Ncs subcarriers becomes the correlation value of each scramble code, and the correlation value of N / Ncs scramble codes is detected by N subcarriers × Navg symbols.
[0139]
Next, the example shown in FIG. 40 (the twelfth embodiment) is an example in the case of Nps = (N / Ncs) / 4. Correlation of (N / Ncs) / Nps = 4 scramble codes is detected alternately for each Ncs subcarrier. Then, the correlation value of each scramble code can be detected by adding Nps powers of the in-phase addition value for each Ncs subcarrier in the frequency direction for each code.
[0140]
When Nps = (N / Ncs) / 4 as in this example, correlation values for four scramble codes are detected using N subcarriers × Navg symbols.
[0141]
Furthermore, the example (13th Embodiment) shown in FIG. 41 is an example in the case of Nps = (N / Ncs) / 2. In this case, correlation values for two scramble codes can be detected using N subcarriers × Navg symbols.
[0142]
【The invention's effect】
According to the present invention, high-speed and high-accuracy spread code synchronization is possible in the MC-CDMA system using a scramble code.
[0143]
The present invention In Therefore, in a mobile communication system using the MC-CDMA system, it is possible to detect the FFT timing of the optimum cell by providing a plurality of candidates even when the total transmission power varies among cells in a multi-cell environment. it can.
[Brief description of the drawings]
FIG. 1 is a block diagram of a transmission apparatus in a conventional MC-CDMA mobile communication system.
FIG. 2 is a diagram showing a scramble code pattern in the conventional example.
FIG. 3 is a block diagram of a transmission apparatus according to the first embodiment of this invention.
FIG. 4 is a diagram illustrating a configuration of a synchronization signal in the transmission apparatus according to the first embodiment of the present invention.
FIG. 5 is a diagram illustrating a configuration of another synchronization signal in the transmission apparatus according to the first embodiment of the present invention.
FIG. 6 is a diagram illustrating a configuration of still another synchronization signal in the transmission apparatus according to the first embodiment of the present invention.
FIG. 7 is a diagram illustrating a configuration of still another synchronization signal in the transmission apparatus according to the first embodiment of the present invention, and a diagram illustrating a synchronization signal timing thereof;
FIG. 8 is a block diagram of a transmission apparatus according to a second embodiment of this invention.
FIG. 9 is a diagram illustrating a configuration of a synchronization signal in the transmission apparatus according to the second embodiment of the present invention.
FIG. 10 is a block diagram of an MC-CDMA receiving apparatus according to a third embodiment of this invention.
FIG. 11 is a block diagram showing a detailed configuration of a scramble code reception timing detection circuit and a scramble code identification circuit in the reception apparatus according to the third embodiment of the present invention.
FIG. 12 is a block diagram showing a detailed configuration of a demodulation circuit in the receiving apparatus according to the third embodiment of the present invention.
FIG. 13 is a flowchart illustrating a multicarrier signal reception method by the reception apparatus according to the third embodiment of the present invention.
FIG. 14 is a block diagram of an MC-CDMA receiving apparatus according to a fourth embodiment of this invention.
FIG. 15 is a flowchart illustrating a multicarrier signal reception method by the reception apparatus according to the fourth embodiment of the present invention.
FIG. 16 is a block diagram of an MC-CDMA reception device according to a fifth embodiment of this invention;
FIG. 17 is a flowchart illustrating a multicarrier signal reception method by the reception apparatus according to the fifth embodiment of the present invention;
FIG. 18 is a block diagram of an MC-CDMA reception device according to a sixth embodiment of this invention;
FIG. 19 is a flowchart illustrating a multicarrier signal reception method by the reception apparatus according to the sixth embodiment of the present invention.
FIG. 20 is a block diagram of an MC-CDMA receiving apparatus according to a seventh embodiment of the present invention.
FIG. 21 is a flowchart illustrating a multicarrier signal reception method by the reception apparatus according to the seventh embodiment of the present invention.
FIG. 22 is a flowchart showing processing for detecting FFT timing from a received signal in a general MC-CDMA system.
FIG. 23 is an explanatory diagram of FFT timing detection processing shown in FIG. 22;
FIG. 24 is a correlation sequence diagram of detected FFT timings.
FIG. 25 is a block diagram of an MC-CDMA reception device according to an eighth embodiment of the present invention;
FIG. 26 is a flowchart illustrating a signal reception method by the reception device according to the eighth embodiment of the present invention.
FIG. 27 is an explanatory diagram illustrating FFT timing candidates determined by the signal reception method by the reception device according to the eighth embodiment of the present invention;
FIG. 28 is a flowchart illustrating a signal reception method by the reception device according to the seventh embodiment of the present invention.
FIG. 29 is an explanatory diagram showing another FFT timing candidate detection method by the reception device according to the eighth embodiment of the present invention;
FIG. 30 is an explanatory diagram showing another FFT timing candidate detection method by the reception device according to the eighth embodiment of the present invention;
FIG. 31 is an explanatory diagram showing still another FFT timing candidate detection method by the reception device according to the eighth embodiment of the present invention;
FIG. 32 is an explanatory diagram showing another FFT timing candidate detection method by the reception device according to the eighth embodiment of the present invention;
FIG. 33 is an explanatory diagram showing still another FFT timing candidate detection method by the reception device according to the eighth embodiment of the present invention;
FIG. 34 is an explanatory diagram showing still another FFT timing candidate detection method by the reception device according to the eighth embodiment of the present invention;
FIG. 35 is an explanatory diagram showing another FFT timing candidate detection method by the reception device according to the eighth embodiment of the present invention;
FIG. 36 is a block diagram of an MC-CDMA reception device according to a ninth embodiment of this invention;
FIG. 37 is a flowchart illustrating a signal reception method by the reception device according to the seventh embodiment of the present invention.
FIG. 38 is a diagram illustrating a correlation detection method for a long-period spread code by the reception device according to the tenth embodiment of the present invention.
FIG. 39 is a diagram illustrating a correlation detection method for a long-period spread code by the reception device according to the eleventh embodiment of the present invention.
FIG. 40 is a diagram illustrating a correlation detection method for a long-period spread code by the reception device according to the twelfth embodiment of the present invention.
FIG. 41 is a diagram illustrating a correlation detection method for a long-period spread code by the reception device according to the thirteenth embodiment of the present invention.
[Explanation of symbols]
10 Transmitter
100 data channel generation circuit
101 Transmission data generator
107 Short-period spreading code generator
108 multiplier
109 1st composition part
110 Scramble code generator
111 multiplier
112 Second synthesis unit
113 IFFT circuit
114 Guard interval inserter
120 synchronization signal generator
121 Data generator
123 Spreading Code Generator for Synchronization Signal
124 multiplier
125 series-parallel converter
126 multiplier
199 antenna
20 Receiver
200 Scramble code reception timing detection circuit
201 Correlator
202 Synchronization signal replica generator
203 Memory of correlation value and timing
204 Timing detection circuit
205 memory
207 Adder
208 Guard interval removal circuit
209 FFT circuit
210 Scramble code identification circuit
211 Scramble code replica generator
212 Correlator
213 Adder
214 Memory of correlation value and code number
215 Scramble code detection circuit
2010 Sync signal correlation detection circuit
2012 correlator
2013 Synchronous signal replica generator
2014 FFT timing setting circuit
2015 guard interval removal circuit
2016 FFT circuit
230 Scramble code correlation detection circuit
240 Scramble code and scramble code reception timing detection circuit
250 FFT timing detection circuit
251 delay circuit
252 multiplier
253 integrator
254 Correlation value and timing memory
255 Timing detection circuit
256 memory
300 Demodulator
301 Scramble code generator
302 FFT timing detector
303 Guard interval removal circuit
304 FFT circuit
305 Channel estimation unit
309 Sheet code generator
310 Adder
312 Data demodulator
313 Decoder

Claims (35)

A short period spreading code product unit for multiplying each of a plurality of transmission data series by a plurality of short period spreading codes,
A long period spreading code product unit that multiplies a long period spreading code common to each of the plurality of transmission data sequences multiplied by the short period spreading code output from the short period spreading code product unit;
The synchronization signal data generating unit for generating the synchronization signal data, the synchronization signal spreading code generating unit for generating the synchronization signal spreading code, and the synchronization signal data generated by the synchronization signal data generating unit A synchronization signal generation unit having a multiplication unit that multiplies the synchronization signal spreading code generated by the spreading code generation unit and outputs the product as a synchronization signal;
Each of the transmission data series obtained by multiplying the short-period spreading code and the long-period spreading code output from the long-period spreading code product section and the synchronization signal data output from the synchronization signal generating section A transmission signal synthesizer that synthesizes a synchronization signal obtained by multiplying only the synchronization signal spreading code in such a manner that the synchronization signal represents the transmission timing of the long-period spreading code by the code sequence pattern of the synchronization signal spreading code. When,
A transmission apparatus in a multi-carrier CDMA mobile communication system, comprising: a transmission processing unit that transmits a combined signal combined by the transmission signal combining means using one or a plurality of subcarriers. 2. The multicarrier CDMA system according to claim 1, wherein the synchronization signal generator multiplies the synchronization signal data with a synchronization signal spreading code at a plurality of timings during a predetermined period. A transmission apparatus in a mobile communication system. A data sequence obtained by multiplying a short-cycle spread code and a long-cycle spread code and a sync signal generated by multiplying the sync signal data by only the sync signal spread code, the sync signal is the sync signal A transmission method in a mobile communication system comprising: combining in a form that represents a transmission timing of the long-period spread code by a code sequence pattern of a spreading code for transmission; and transmitting using one or a plurality of subcarriers. The transmission method in the mobile communication system according to claim 3, wherein the synchronization signal is transmitted in a known time interval in a burst manner. The transmission method in the mobile communication system according to claim 3, wherein the synchronization signal represents a transmission timing of the long-period spreading code according to a transmission timing. The transmission method in the mobile communication system according to claim 3, wherein the synchronization signal represents a transmission timing of the long-period spreading code by a transmission timing and a transmitted subcarrier. A multi-carrier CDMA mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers A receiving device in
A signal receiving unit that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code;
A correlator for obtaining a correlation value between the multicarrier signal received by the signal receiving unit and a synchronization signal replica;
A receiving apparatus in a multi-carrier CDMA mobile communication system, comprising: a timing detector that detects an FFT timing and a reception timing of the long-period spread code according to the correlation value obtained by the correlator. A multi-carrier CDMA mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers A receiving device in
A signal receiving unit that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code;
A first correlator for obtaining a correlation value between the multicarrier signal received by the signal receiving unit and a synchronization signal replica;
A timing detector that detects FFT timing and the reception timing of the long-period spread code according to the correlation value obtained by the first correlator;
An FFT circuit that performs FFT according to the FFT timing detected by the timing detection unit and separates the multicarrier signal into a plurality of subcarrier components;
The plurality of subcarrier components separated by the FFT circuit according to the reception timing of the long-period spreading code detected by the timing detection unit, each long-period spreading code included in the long-period spreading code group, and the A second correlator for obtaining a correlation value with a code sequence obtained by multiplying a short-period spreading code by double multiplication;
A code detection unit for detecting a long-period spreading code for spreading the multicarrier signal according to the correlation value obtained by the second correlator;
The data sequence is demodulated from the multicarrier signal received by the signal receiving unit using the reception timing of the long period spreading code detected by the timing detecting unit and the long period spreading code detected by the code detecting unit. Receiving device in a multi-carrier CDMA mobile communication system. A multi-carrier CDMA mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers A receiving device in
A signal receiving unit that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code;
A subcarrier separation unit that performs FFT according to a plurality of FFT timings and separates the multicarrier signal received by the signal reception unit into a plurality of subcarrier components;
Of the plurality of subcarrier components separated by the subcarrier separation unit, a correlator for obtaining a correlation value between a subcarrier component included in the synchronization signal and a synchronization signal replica;
A receiving apparatus in a multi-carrier CDMA mobile communication system, comprising: a timing detection unit that detects reception timing and FFT timing of the long-period spread code according to a correlation value obtained by the correlator. A multi-carrier CDMA mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers A receiving device in
A signal receiving unit that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code;
A subcarrier separation unit that performs FFT according to a plurality of FFT timings and separates the multicarrier signal received by the signal reception unit into a plurality of subcarrier components;
A first correlator for obtaining a correlation value between a subcarrier component included in the synchronization signal and a synchronization signal replica among the plurality of subcarrier components separated by the subcarrier separation unit;
A timing detector that detects the reception timing and FFT timing of the long-period spread code according to the correlation value obtained by the first correlator;
An FFT circuit that performs FFT according to the FFT timing detected by the timing detection unit and separates the multicarrier signal into a plurality of subcarrier components;
A plurality of subcarrier components separated by the FFT circuit, each long-period spreading code included in the long-period spreading code group, and the short A second correlator for obtaining a correlation value with a code sequence obtained by multiplying the cyclic spreading code by a double product;
A code detection unit for detecting a long-period spreading code for spreading the multicarrier signal according to the correlation value obtained by the second correlator;
The data sequence is demodulated from the multicarrier signal received by the signal receiving unit using the reception timing of the long period spreading code detected by the timing detecting unit and the long period spreading code detected by the code detecting unit. Receiving device in a multi-carrier CDMA mobile communication system. A multi-carrier CDMA mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers A receiving device in
A signal receiving unit that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code;
A subcarrier separation unit that separates the multicarrier signal received by the signal reception unit into a plurality of subcarrier components;
Of the plurality of subcarrier components separated by the subcarrier separation unit, a correlator for obtaining a correlation value between a subcarrier component including the synchronization signal and a synchronization signal replica;
A receiving apparatus in a multi-carrier CDMA mobile communication system, comprising: a timing detection unit that detects reception timing of the long-period spread code according to the correlation value obtained by the correlator. A multi-carrier CDMA mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers A receiving device in
A signal receiving unit that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code;
A subcarrier separation unit that separates the multicarrier signal received by the signal reception unit into a plurality of subcarrier components;
A first correlator for obtaining a correlation value between a subcarrier component including the synchronization signal and a synchronization signal replica among the plurality of subcarrier components separated by the subcarrier separation unit;
A timing detector for detecting a reception timing of the long-period spread code according to the correlation value obtained by the first correlator;
The plurality of subcarrier components separated by the subcarrier separation unit according to the reception timing of the long period spreading code detected by the timing detection unit, and each long period spreading code included in the long period spreading code group And a second correlator for obtaining a correlation value between a code sequence obtained by multiplying the short period spread code and the short period spreading code;
A code detection unit for detecting a long-period spreading code for spreading the multicarrier signal according to the correlation value obtained by the second correlator;
The data sequence is demodulated from the multicarrier signal received by the signal receiving unit using the reception timing of the long period spreading code detected by the timing detecting unit and the long period spreading code detected by the code detecting unit. Receiving device in a multi-carrier CDMA mobile communication system. A multi-carrier CDMA mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers A receiving device in
A signal receiving unit that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code;
A subcarrier separation unit that performs FFT according to each of a plurality of FFT timings and separates the multicarrier signal received by the signal reception unit into a plurality of sets each including a plurality of subcarrier components;
A first correlator for obtaining a correlation value between a subcarrier component including the synchronization signal and the synchronization signal replica among the plurality of subcarrier components separated by the subcarrier separation unit for each of the plurality of sets;
A timing detection unit that detects a plurality of reception timing candidates of the long-period spread code according to the plurality of correlation values obtained by the first correlator;
The plurality of sub-carrier components, each long-period spreading code included in the long-period spreading code group, and the short period according to the reception timing candidates of the plurality of long-period spreading codes detected by the timing detection unit. A second correlator for obtaining a correlation value with each of the plurality of sets of code sequences obtained by multiply multiplying a spreading code;
A code candidate detection unit that detects each of a plurality of long-period spread code candidates for spreading the multicarrier signal according to each of the plurality of correlation values obtained by the second correlator;
The reception timing of the long-period spreading code and the long-period spreading code are detected from a plurality of reception timing candidates detected by the timing detection section and a plurality of long-period spreading code candidates detected by the code candidate detection section. Timing and code detection unit,
A demodulation circuit for demodulating the data sequence from the multicarrier signal received by the signal reception unit using the reception timing of the long period spreading code detected by the timing and code detection unit and the long period spreading code; A receiving apparatus in a multi-carrier CDMA mobile communication system. A multi-carrier CDMA mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers A receiving device in
A signal receiving unit that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code;
An FFT timing detection unit that detects an FFT timing from the multicarrier signal received by the signal reception unit based on a correlation characteristic of a guard interval included in the multicarrier signal;
A subcarrier separation unit that performs FFT at the FFT timing detected by the FFT timing detection unit and separates into a plurality of subcarrier components;
Of the plurality of subcarrier components separated by the subcarrier separation unit, a correlator for obtaining a correlation value between a subcarrier component including the synchronization signal and a synchronization signal replica;
A receiving apparatus in a multi-carrier CDMA mobile communication system, comprising: a timing detection unit that detects reception timing of the long-period spread code according to a correlation value obtained by the correlator. A multi-carrier CDMA mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers A receiving device in
A signal receiving unit that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code;
An FFT timing detection unit that detects an FFT timing from the multicarrier signal received by the signal reception unit based on a correlation characteristic of a guard interval included in the multicarrier signal;
A subcarrier separation unit that performs FFT at the FFT timing detected by the FFT timing detection unit and separates into a plurality of subcarrier components;
A first correlator for obtaining a correlation value between a subcarrier component including the synchronization signal and a synchronization signal replica among the plurality of subcarrier components separated by the subcarrier separation unit;
A timing detector for detecting the reception timing of the long-period spread code according to the correlation value obtained by the first correlator;
The subcarrier component separated by the subcarrier separation unit according to the reception timing of the long period spreading code detected by the timing detection unit, each long period spreading code included in the long period spreading code group, and the short A second correlator for obtaining a correlation value with a code sequence obtained by multiplying the cyclic spreading code by a double product;
A code detection unit for detecting a long-period spreading code for spreading the multicarrier signal according to the correlation value obtained by the second correlator;
The data sequence is demodulated from the multicarrier signal received by the signal receiving unit using the reception timing of the long period spreading code detected by the timing detecting unit and the long period spreading code detected by the code detecting unit. Receiving device in a multi-carrier CDMA mobile communication system. In a receiving method in a mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers,
A reception step of receiving a reception signal including the plurality of subcarriers having a synchronization signal obtained by multiplying one or a plurality of subcarriers with only a synchronization signal spreading code;
A correlation output step for outputting a correlation value between the reception signal received in the reception step and the synchronization signal replica;
A reception method in a mobile communication system, comprising: an FFT timing and a timing detection step of detecting a reception timing of the long-period spread code according to the correlation value output in the correlation output step. In a receiving method in a mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers,
A reception step of receiving a reception signal including the plurality of subcarriers having a synchronization signal obtained by multiplying one or a plurality of subcarriers with only a synchronization signal spreading code;
A separation step of separating the received signal received in the reception step into a plurality of subcarrier components;
A correlation output step of outputting a correlation value between a subcarrier component included in the synchronization signal and a synchronization signal replica among the plurality of subcarrier components separated in the separation step;
And a timing detection step of detecting a reception timing of the long-period spread code according to the correlation value output in the correlation output step. The separation step performs FFT according to a plurality of FFT timings,
The timing detection step detects a target FFT timing and a reception timing of the long-period spreading code according to the correlation value output in the correlation output step for all the FFT timings. Item 18. A receiving method in the mobile communication system according to Item 17 . A separation step of performing FFT according to the FFT timing detected in the timing detection step, and separating the received signal into a plurality of subcarrier components;
Depending on the reception timing of the long-period spreading code detected in the timing detection step, the subcarrier component, each long-period spreading code included in the long-period spreading code group, and the short-period spreading code are divided into two. A correlation detection step for outputting a correlation detection value with a multiply-signed code sequence;
The mobile communication according to claim 16 or 18 , further comprising a code detection step of detecting a long-period spreading code for spreading the received signal in accordance with the correlation detection value output from the correlation detection step. Reception method in the system. In a receiving method in a mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers,
A reception step of receiving a reception signal including the plurality of subcarriers having a synchronization signal obtained by multiplying one or a plurality of subcarriers with only a synchronization signal spreading code;
A separation step of performing FFT according to a plurality of FFT timings to separate the received signal received in the reception step into a plurality of subcarrier components;
A correlation output step of outputting a correlation value between a subcarrier component included in the synchronization signal and a synchronization signal replica among the plurality of subcarrier components separated in the separation step;
A timing detection step of detecting the reception timing of the long-period spread code according to the correlation value output in the correlation output step;
According to the reception timing of the long-period spreading code detected in the timing detection step, the subcarrier component, each long-period spreading code included in the long-period spreading code group, and the short-period spreading code are divided into two. A correlation detection step of outputting a correlation detection value with the multiply multiplied code sequence;
For all the FFT timings, the FFT timing, the reception timing of the long-period spreading code, and the long-period spreading code that spreads the received signal are detected according to the correlation detection value output from the correlation detection step. A receiving method in a mobile communication system. In a receiving method in a mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers,
FFT timing detection step for detecting FFT timing based on the correlation characteristics of the guard interval included in the received multicarrier signal;
A separation step of performing FFT at the FFT timing obtained in the FFT timing detection step and separating the FFT timing into a plurality of subcarrier components;
A correlation output step of outputting a correlation value between a subcarrier component included in the synchronization signal and a synchronization signal replica among the plurality of subcarrier components separated in the separation step;
And a timing detection step of detecting a reception timing of the long-period spread code according to the correlation value output in the correlation output step. According to the reception timing of the long-period spreading code detected in the timing detection step, the subcarrier component, each long-period spreading code included in the long-period spreading code group, and the short-period spreading code are duplicated. A correlation detection step for outputting a correlation detection value with a code sequence multiplied by
The mobile communication system according to claim 21 , further comprising a code detection step of detecting a long-period spread code for spreading the received signal in accordance with the correlation detection value output from the correlation detection step. Reception method. A multi-carrier CDMA mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers A receiving device in
A signal receiving unit that receives a multicarrier signal including a synchronization signal obtained by multiplying only one or a plurality of subcarriers by a synchronization signal spreading code;
An FFT timing detection unit that detects a plurality of FFT timing candidates from the multicarrier signal received by the signal reception unit based on correlation characteristics of guard intervals included in the multicarrier signal;
The FFT timing detector
A multiplier for multiplying the multicarrier signal by a signal obtained by delaying the multicarrier signal by one symbol length;
An integrator for integrating a multiplication value multiplied by the multiplication unit over one guard interval length to obtain a correlation value;
A first memory for storing the correlation value obtained by the integrator and its timing;
A second memory for storing a plurality of FFT timing candidates given sequentially,
A search range setting unit configured to set a search range for each of the plurality of FFT timing candidates based on the plurality of FFT timing candidates stored in the second memory and the stored value of the first memory;
First, the maximum correlation value and timing are selected from the stored values of the first memory, stored in the second memory as the FFT timing candidate # 1, and then the second search range setting unit stores the second correlation value. The search range is set based on the FFT timing candidate stored in the memory and the stored value of the first memory, and the maximum correlation value and timing are selected from the stored value of the first memory within the search range. A multi-carrier CDMA system comprising: a timing detection circuit that stores in the second memory as FFT timing candidate # 2 and repeats detection until a predetermined number of predetermined FFT timing candidates are detected in the same procedure Receiving device in a mobile communication system. The receiving apparatus in the multi-carrier CDMA mobile communication system according to claim 23 ,
A plurality of subcarrier separation units for performing FFT on the multicarrier signal in each of the predetermined number of FFT timing candidates detected by the FFT timing detection unit, and separating the subcarrier components into a plurality of subcarrier components;
Among the plurality of subcarrier components separated by each of the plurality of subcarrier separation units, a plurality of first correlators for obtaining a correlation value between a subcarrier component including the synchronization signal and a synchronization signal replica;
A plurality of timing detectors for detecting reception timing candidates of the long-period spread code according to the correlation values obtained by the plurality of first correlators;
The plurality of subcarrier components and the respective long-period spreading codes included in the long-period spreading code group according to the reception timing candidates of the plurality of long-period spreading codes detected by the plurality of timing detection units, respectively. A plurality of second correlators for obtaining a correlation value with a code sequence obtained by multiplying the short-period spreading code by a double product;
A plurality of code candidate detection units for detecting each of a plurality of long-period spread code candidates for spreading the multicarrier signal according to each of the plurality of correlation values obtained by each of the plurality of second correlators;
From the plurality of reception timing candidates detected by the plurality of timing detection units and the plurality of long period spreading code candidates detected by the plurality of code candidate detection units, the reception timing of the long period spreading code and the long period A timing for detecting a spreading code and a code detection unit;
A demodulation circuit for demodulating the data sequence from the multicarrier signal received by the signal reception unit using the reception timing of the long period spreading code detected by the timing and code detection unit and the long period spreading code; A receiving apparatus in a multi-carrier CDMA mobile communication system. The receiving apparatus in the multi-carrier CDMA mobile communication system according to claim 23 ,
A plurality of first FFT circuits for performing FFT on the multicarrier signal in each of the predetermined number of FFT timing candidates detected by the FFT timing detection unit and separating the multicarrier signal into a plurality of subcarrier components;
A plurality of first correlators for obtaining a correlation value between a subcarrier component including the synchronization signal and a synchronization signal replica among the plurality of subcarrier components separated from each other by the plurality of first FFT circuits;
A timing detector that detects the reception timing and FFT timing of the long-period spread code according to the correlation value obtained by each of the plurality of first correlators;
A second FFT circuit that performs FFT according to the FFT timing detected by the timing detection unit and separates the multicarrier signal into a plurality of subcarrier components;
A plurality of subcarrier components separated by the second FFT circuit according to the reception timing of the long period spreading code detected by the timing detection unit, and each long period spreading code included in the long period spreading code group And a second correlator for obtaining a correlation value between a code sequence obtained by multiplying the short period spread code and the short period spreading code;
A code detection unit for detecting a long-period spreading code for spreading the multicarrier signal according to the correlation value obtained by the second correlator;
The data sequence is demodulated from the multicarrier signal received by the signal receiving unit using the reception timing of the long period spreading code detected by the timing detecting unit and the long period spreading code detected by the code detecting unit. Receiving device in a multi-carrier CDMA mobile communication system. In a signal reception method in a mobile communication system that transmits a code sequence using a plurality of subcarriers,
A signal receiving method in a mobile communication system, comprising: detecting a plurality of FFT timing candidates from a correlation characteristic of a guard interval. The signal reception method in the mobile communication system according to claim 26 ,
Multiplying the received signal by a signal obtained by delaying the received signal by one symbol length;
A step of moving average the obtained multiplication values using the average interval as a guard interval length;
In-phase addition of a correlation sequence of a plurality of correlation values obtained by moving average for each guard interval insertion period;
A method for receiving a signal in a mobile communication system, comprising: detecting a plurality of FFT timing candidates from a correlation sequence having a length equal to a guard interval insertion period obtained by in-phase addition. The signal reception method in the mobile communication system according to claim 27 ,
In the correlation sequence having a length equal to the guard interval insertion period obtained by the in-phase addition, a step having a timing having the maximum correlation value as a first FFT timing candidate;
For each of the second and subsequent FFT timing candidates, the timing having the maximum correlation value in the remaining correlation sequences obtained by excluding the surrounding W samples of each detected FFT timing candidate as an exclusion window is set as the next FFT timing candidate. A method for receiving a signal in a mobile communication system, comprising: detecting up to a predetermined number by repeating the method. The signal reception method in the mobile communication system according to claim 28 ,
The exclusion window is set at the front and back with a preset width of W / 2 samples around the FFT timing candidate already detected when setting the window. Reception method. The signal reception method in the mobile communication system according to claim 28 ,
The number of samples W of the exclusion window and its position are set based on the magnitude of the slope of the correlation sequence with the position of the FFT timing candidate already detected when the exclusion window is set as a vertex. A signal receiving method in a mobile communication system. The signal reception method in the mobile communication system according to claim 28 ,
The number of samples W and the position of the exclusion window are set based on the magnitude of the correlation value in the FFT timing candidate that has already been detected when setting the exclusion window. Receiving method. The signal reception method in the mobile communication system according to any one of claims 28 to 31 ,
A signal receiving method in a mobile communication system, comprising a step of providing a plurality of FFT timing candidates before and after a detected FFT timing candidate. The signal reception method in the mobile communication system according to claim 27 to 32 ,
Performing FFT on a plurality of FFT timing candidates and separating them into a plurality of subcarrier components;
A step of outputting a correlation value between a subcarrier component including a synchronization signal and a synchronization signal replica among the plurality of separated subcarrier components;
Detecting one or a plurality of long-period spreading code reception timing candidates according to the output correlation value;
Depending on the detected reception timing candidates of one or a plurality of long-period spreading codes, the subcarrier component and each long-period spreading code and short-period spreading code included in the long-period spreading code group are doubled. Outputting a correlation detection value with the multiplied code sequence;
Detecting FFT timing, reception timing of the long-period spreading code, and long-period spreading code for spreading the received signal for all detected FFT timing candidates in accordance with the output correlation detection value. A signal receiving method in a mobile communication system. A signal receiving method in a mobile communication system for transmitting a data sequence obtained by multiplying a short period spreading code and any one long period spreading code included in a long period spreading code group by using a plurality of subcarriers In
A signal sequence obtained by dividing the received signal into subcarrier components by processing such as FFT, and a double product of each long-period spreading code and short-period spreading code included in the long-period spreading code group When outputting the correlation detection value,
For each subcarrier, the correlation value of each symbol is added in-phase with Navg symbols (Navg is an integer of 1 or more) in the time direction,
The in-phase addition value for each subcarrier is added in-phase over Ncs subcarriers (Ncs is an integer satisfying 1 ≦ Ncs ≦ N, where N is the number of subcarriers) adjacent in the frequency direction.
An average correlation value is detected by adding Nps in-phase addition values for each Ncs subcarrier in the frequency direction (Nps is an integer satisfying 1 ≦ Nps ≦ N / Ncs). Reception method. 35. The mobile communication according to claim 34 , wherein when Nps <(N / Ncs), (N / Ncs) / Nps long-period spreading codes are alternately detected for each Ncs subcarrier in the frequency direction. How to receive signals in the system.

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