JP2000354020A - Receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the hardware scale of a receiver which can receive OFDM signals from a base station, as well as OFDM signals from mobile stations through a random access channel. SOLUTION: While a receiver stays in a random access channel, a selector 107 switches so that a synchronizing symbol for BS may be inputted to a synchronization acquiring section 106, and another synchronization acquiring section 105 detects synchronization by calculating the correlative value between a received signal and a synchronizing symbol for MS. The synchronization acquiring section 106 detects synchronization by calculating the correlative value between the received signal, and the synchronizing symbol for BS and a selecting section 108 sets the symbol synchronizing timing detected by means of a synchronization acquiring section installed to a branch acquiring synchronization at the processing start timing of FFT processing sections 109 and 110.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a receiving device,
In particular, a receiver used for OFDM mobile communication and its random access channel (Random)
Access channel (hereinafter referred to as “RAch”).

[0002]

2. Description of the Related Art In mobile communication, the access method is T.
When a time division scheme such as DMA or CDMA / TDD is used, an uplink (Up Link; hereinafter, referred to as “UL”) and a downlink (Down Link; hereinafter, “DL”) are used.
), It is necessary to establish synchronization between base stations.

[0003] This will be described with reference to FIG.
The base station 301 denoted by 1 needs to establish synchronization not only with the mobile station 302 in its own cell denoted by MS in the figure, but also with the base station 303 denoted by BS2 in the figure.

FIG. 4A shows an example of a frame format of a transmission signal when the time division method is adopted. One frame includes DL 401, UL 402, and RACh 40
3 and each DL and each UL consists of a plurality of channels.

[0005] DL 401 is used for transmission from the base station to the mobile station, and UL 402 is used for transmission from the mobile station to the base station. Therefore, establishment of synchronization between base stations is represented by R
This is performed using Ach403.

[0006] However, the RACh 403 is not only used for establishing synchronization between base stations, but is also used randomly for communication with mobile stations. Therefore, the base station apparatus calculates R
In the Ach section, it is necessary to be able to receive a signal from a mobile station and a signal from another base station.

Here, an example of a frame format of a transmission signal from a mobile station is shown in FIG. 4 (b), and an example of a frame format of a transmission signal from a base station is shown in FIG. 4 (c). The transmission signal from the mobile station includes a synchronization symbol for MS 404, a pilot symbol 405, and an effective symbol 406, and the transmission signal from the base station is a BS.
Synchronization symbol 407 and pilot symbol 408
And an effective symbol 409. Here, the MS synchronization symbol 404 and the BS synchronization symbol 407 are different known signals, the pilot symbol is used for phase rotation detection, and the effective symbol is a symbol including transmission data.

Therefore, the conventional base station apparatus has two reception processing systems, and establishes synchronization using different known signals, so that the random access between the signal from the mobile station and the signal from the base station in RAch is achieved. Realized reception.

[0009] A receiving apparatus used in a conventional base station apparatus will be described below with reference to FIGS. 5 and 6. FIG.
Is a main block diagram showing a schematic configuration of a conventional receiving apparatus, and FIG. 6 is a main block diagram showing a schematic configuration of a synchronization acquiring section of the conventional receiving apparatus. Here, it is assumed that the number of branches is two.

[0010] In FIG. 5, an antenna 501 as a branch 1 and an antenna 502 as a branch 2 receive a radio signal and receive signals from a reception processing unit 503 and a reception processing unit 504.
Performs reception processing on signals received by the antenna 501 and the antenna 502, respectively.

Synchronization acquisition sections 505 to 508 acquire synchronization from the correlation value between the received signal and the known signal, and output symbol synchronization timing. If synchronization is not obtained, no symbol synchronization timing is output. Here, the synchronization acquisition unit 5
05 detects synchronization using the synchronization symbol for BS as a known signal with respect to the reception signal of the branch 1, and similarly, the synchronization acquisition unit 506 uses the synchronization symbol for BS for the reception signal of the branch 2. , The synchronization acquisition unit 507 detects the synchronization using the MS synchronization symbol for the reception signal of the branch 1, and the synchronization acquisition unit 508 detects the synchronization using the synchronization symbol for the MS for the reception signal of the branch 2. The configuration in each synchronization acquisition unit will be described later.

The FFT processing unit 509 includes a synchronization acquisition unit 505
The received signal of branch 1 is FF
The TFT processing is performed, and similarly, the FFT processing unit 510 performs the FFT processing on the reception signal of the branch 2 using the symbol synchronization timing acquired by the synchronization acquisition unit 506 as the processing start timing. ,
Using the symbol synchronization timing acquired by the synchronization acquisition section 507 as the processing start timing, the FFT processing is performed on the reception signal of the branch 1 and the FFT processing section 512
Performs FFT processing on the received signal of branch 2 using the symbol synchronization timing acquired by the synchronization acquisition section 508 as the processing start timing.

[0013] Demodulation section 513 performs demodulation processing, error detection, and error correction processing on the received signal that has been subjected to FFT processing by FFT processing section 509 and FFT processing section 510, and performs data transmission from another base station ( BS data). The demodulation unit 514 includes an FFT processing unit 511 and FFT processing unit 511.
The demodulation processing, the error detection, and the error correction processing are performed on the reception signal that has been subjected to the FFT processing by the FT processing unit 512,
The data (MS data) transmitted from the mobile station is output.

Unless synchronization is obtained, neither FFT processing nor demodulation processing is performed.

Next, referring to FIG.
The configuration of to 508 will be described. In FIG. 6, a correlator 601 calculates a correlation between the input received signal of the branch 1 or the received signal of the branch 2 and the known signal. Here, the known signal is a signal obtained by performing the IFFT processing on the BS synchronization symbol or a signal obtained by performing the IFFT processing on the MS synchronization symbol.

The absolute value detecting section 602 detects the absolute value of the correlation result, and the determining section 603 integrates the absolute value of the correlation result, and determines whether or not the integrated value exceeds an arbitrary threshold. If the integrated value exceeds the threshold value, it is determined that synchronization has been established. If the integrated value does not exceed the threshold value, it is determined that synchronization has not been established.

The maximum value detecting section 604 detects the timing at which the integrated correlation value takes the maximum value, and the timing generating section 605 sets the detected timing as the symbol synchronization timing.

The start timing of the FFT processing is not limited to the timing of independent execution for each branch as described above. A method of using a simplified timing has been proposed.

As described above, the receiving apparatus in the conventional base station apparatus has two receiving systems and obtains synchronization using different known signals.
Both a transmission signal from another base station and a transmission signal from a mobile station can be received at random.

[0020]

However, since the conventional receiving apparatus has two receiving processing systems,
The problem that a hardware scale becomes large arises.

The present invention has been made in view of the above points, and a receiving apparatus with a reduced hardware scale and its RAc
An object of the present invention is to provide a synchronization acquisition method in the h section.

[0022]

The gist of the present invention is that, in one reception processing system, in a RACh section, synchronization is acquired using a known signal different for each branch, and symbol synchronization timing in a branch where synchronization has been established. Is used as the symbol synchronization timing in the reception signals of all branches.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A receiving apparatus according to a first aspect of the present invention comprises a receiving means for receiving an OFDM signal in a plurality of branches, and a correlation between a received signal of each branch and a known signal different for each branch previously held. Branches whose values have been integrated and whose integrated value exceeds an arbitrary threshold value are determined by a synchronization acquisition determining unit that determines that synchronization has been established, and a branch that has been determined by the synchronization acquisition determining unit that synchronization has been established. And a synchronization timing setting means for setting the timing at which the integrated value takes the maximum value as the symbol synchronization timing in all branches.

According to this configuration, synchronization is obtained using a known signal that differs for each branch, and the symbol synchronization timing in the branch in which synchronization is established is used as the symbol synchronization timing in the reception signals of all branches. Even in a time zone where it is unclear from which of the plurality of transmitting stations using the synchronization symbol a signal is being transmitted, the signal can be received by one reception processing system, so that the hardware scale of the base station apparatus can be reduced. .

[0025] The base station apparatus according to the second aspect of the present invention comprises:
The receiving apparatus according to the first aspect, wherein the known signal includes a synchronization symbol added to transmission data by the mobile station,
And a synchronization symbol added to transmission data by the base station.

[0026] The base station apparatus according to the third aspect of the present invention comprises:
In the second aspect, during a time period in which communication is performed only with the mobile station, all of the known signals that take a correlation value with the received signal of each branch are used as synchronization symbols added to transmission data by the mobile station, and the mobile station and other In a time zone for performing random communication with the base station, the synchronization symbol added to the transmission data by the mobile station as the known signal taking a correlation value with the reception signal of each branch and the synchronization symbol added to the transmission data by the base station. A configuration using a symbol is adopted.

According to these configurations, synchronization is obtained using a known signal that differs for each branch, and the symbol synchronization timing in the branch in which synchronization is established is used as the symbol synchronization timing in the reception signals of all branches. RAch also in one reception processing system
Since signals from the mobile station and other base stations can be randomly received in the section, the hardware scale of the base station device can be reduced.

A communication terminal apparatus according to a fourth aspect of the present invention employs a configuration for performing wireless communication with the base station apparatus according to the second aspect or the third aspect.

According to this configuration, by using different synchronization symbols between the mobile station and the base station, the base station, which is the receiving station, receives signals from the mobile station and other base stations at random in the RACh section. Therefore, the hardware scale of the base station device can be reduced.

[0030] In a synchronization acquisition method according to a fifth aspect of the present invention, an OFDM signal is received in a plurality of branches and a correlation value between the OFDM signal and a known signal is determined in a time zone in which communication is performed randomly with a mobile station or another base station. When calculating, using a synchronization symbol that the mobile station adds to the transmission data as a known signal for a predetermined branch, using a synchronization symbol that the base station adds to the transmission data as a known signal for another predetermined branch, The timing at which the integrated value of the branch in which the calculated integrated value of the correlation value exceeds an arbitrary threshold value takes the maximum value is set as the symbol synchronization timing in all branches.

According to this method, synchronization is obtained by using a known signal that differs for each branch, and the symbol synchronization timing in the branch in which synchronization is established is used as the symbol synchronization timing in the reception signals of all branches, thereby achieving one synchronization. Also in the reception processing system, signals from the mobile station and other base stations can be randomly received in the RAch section, so that the hardware scale of the base station device can be reduced.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. It is assumed that the number of branches is two.

Hereinafter, the receiving apparatus according to the present embodiment will be described using FIG. 1 and FIG. FIG. 1 is a main block diagram showing a schematic configuration of a receiving apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic configuration of a selecting section of the receiving apparatus according to an embodiment of the present invention. It is a principal part block diagram.

In FIG. 1, an antenna 101 serving as a branch 1 and an antenna 102 serving as a branch 2 receive a radio signal, and receive signals from a reception processing unit 103 and a reception processing unit 104.
Performs reception processing on the signals received by the antenna 101 and the antenna 102, respectively.

Synchronization acquisition sections 105 to 106 acquire synchronization from the correlation value between the received signal and the known signal, and output symbol synchronization timing. Since the configuration of the synchronization acquisition unit is the same as that of the related art, a detailed description of the configuration is omitted.

Here, the synchronization acquisition unit 105 determines whether the branch 1
The synchronization acquisition unit 106 detects the synchronization using the MS synchronization symbol as a known signal with respect to the received signal of the branch 2 and outputs the MS synchronization symbol to the received signal of the branch 2 in the DL section and the UL section. , And in the RACh section, the synchronization is detected using the BS synchronization symbol as a known signal for the received signal of branch 2.

The selector 107 operates based on the control signal.
In the DL section and the UL section, switching is performed so that the synchronization symbol for MS is input to the synchronization acquisition section 106,
In the RACh section, switching is performed so that the BS synchronization symbol is input to the synchronization acquisition section 106. The control signal is an instruction signal indicating which time zone of DL / UL / RAch is used. Since these time zones are assigned by the base station apparatus, the control signal is known.

[0038] The selection unit 108 selects
Detecting which of synchronization acquisition section 105 and synchronization acquisition section 106 has acquired the synchronization, demodulation section 1 as an identification signal
11, and outputs the symbol synchronization timing of the one in which the synchronization is acquired to the FFT processing unit 109 and the FFT processing unit 11.
Output to 0.

FFT processing section 109 performs FFT processing on the received signal of branch 1 based on the symbol synchronization timing selected by selection section 108, and FFT processing section 110 performs symbol synchronization selected by selection section 108. FFT processing is performed on the received signal of branch 2 based on the timing.

The demodulation section 111 performs demodulation processing, error detection, and error correction processing on the reception signal subjected to FFT processing by the FFT processing section 109 and the FFT processing section 110, and performs data transmission from the mobile station or other data. Outputs the data transmitted from the base station.

Here, since the data length differs between the received signal from the mobile station and the received signal from another base station, the demodulation unit 1
11 performs demodulation processing, error detection, and error correction processing after changing settings based on the identification signal output from the selection unit 108.

Next, the configuration of the selection unit 108 will be described with reference to FIG. In FIG. 2, a counter 201
Is a counter that is counted when synchronization is acquired by the synchronization acquisition unit 105, and the counter 202 is a counter that is counted when synchronization is acquired by the synchronization acquisition unit 106.

The comparing section 203 compares the count value of the counter 201 with the count value of the counter 202, and
If the count value of 01 is larger, it is determined that the received signal is a signal transmitted from the mobile station. If the count value of the counter 202 is larger, the received signal is a signal transmitted from another base station. It determines that there is, and outputs an identification signal indicating the result of this determination.

The selector 204 determines whether one of the symbol synchronization timing detected by the synchronization acquisition section 105 and the symbol synchronization timing detected by the synchronization acquisition section 106 is based on the identification signal output from the comparison section 203 and the FFT processing section 109. And is input to the FFT processing unit 110. That is, the timing detected for branch 1 is used for a signal received from a mobile station, and the timing detected for branch 2 is used for a signal received from another base station.

Next, the operation of the receiving apparatus according to the present embodiment will be described.

The OFDM signal is received by the antenna 101 and the antenna 102, and received by the reception processing unit 103 and the reception processing unit 104.

DL where base station and mobile station are communicating
In the section and the UL section, the synchronization symbol for MS is input to the synchronization acquisition section 106, that is, in all the synchronization acquisition sections, synchronization is detected using the synchronization symbol for MS.

In a RACh section in which it is not determined whether a signal from another base station or a signal from a mobile station is received, a BS synchronization symbol is input to synchronization acquisition section 106, that is, in branch 1 and branch 2. Detection of synchronization is performed using different known signals.

The counter provided in the branch in which the synchronization is obtained is counted, and the counter provided in the branch in which the synchronization is not obtained remains 0.
The branch for which synchronization has been acquired is detected by the comparing unit 203.

The symbol synchronization timing detected for the branch for which synchronization has been obtained is set by the selection unit 108 as the processing start timing of the FFT processing unit 109 and the FFT processing unit 110.

The received signal subjected to the reception processing is subjected to FFT processing by FFT processing section 109 and FFT processing section 110, demodulation processing, error detection and error correction processing are performed by demodulation section 111, and from another base station. Obtain transmitted data or data transmitted from a mobile station.

As described above, according to the present embodiment, synchronization is obtained by using different known signals for each branch, and the symbol synchronization timing in the branch in which synchronization is established is used as the symbol synchronization timing in the reception signals of all branches. By using this, even in one reception processing system, signals from the mobile station and other base stations can be randomly received in the RAch section, so that the hardware scale of the base station device can be reduced.

Note that, also in the present embodiment, the frame format is not limited to the example shown in FIG. 4, and may include AGC symbols and guard intervals.

[0054]

As described above, according to the present invention,
Synchronization is acquired by using a known signal that differs for each branch, and the symbol synchronization timing in the branch in which synchronization is established is used as the symbol synchronization timing in the reception signals of all branches, so that even one reception processing system moves in the RACh section. Since signals from the station and other base stations can be received at random, the hardware scale of the base station device can be reduced.

[Brief description of the drawings]

FIG. 1 is a main block diagram showing a schematic configuration of a receiving apparatus according to an embodiment of the present invention.

FIG. 2 is a main block diagram showing a schematic configuration of a selection unit of the receiving apparatus according to one embodiment of the present invention;

FIG. 3 is a schematic diagram for explaining establishment of synchronization between base stations.

4A is a schematic diagram illustrating an example of a frame format of a transmission signal when a time division method is adopted; FIG. 4B is a schematic diagram illustrating an example of a frame format of a transmission signal from a mobile station; Schematic diagram showing an example of a signal frame format

FIG. 5 is a main block diagram showing a schematic configuration of a conventional receiving apparatus.

FIG. 6 is a main block diagram showing a schematic configuration of a synchronization acquisition section of a conventional receiving apparatus.

[Explanation of symbols]

 107 selector 108 selector

Claims (5)

[Claims] 1. A receiving means for receiving an OFDM signal at a plurality of branches, a correlation value between a received signal of each branch and a known signal different for each branch held in advance, and the integrated value is an arbitrary threshold. The branch exceeding the value is determined by the synchronization acquisition determining means for determining that synchronization has been established, and the timing at which the integrated value of the branch determined to have been established by the synchronization acquisition determining means has the maximum value. And a synchronization timing setting means for setting as symbol synchronization timing in the above. 2. The reception device according to claim 1, wherein the known signal includes a synchronization symbol added to transmission data by the mobile station and a synchronization symbol added to transmission data by the base station. A base station device characterized by the above-mentioned. 3. In a time zone in which communication is performed only with a mobile station, all of the known signals that take a correlation value with a received signal of each branch are used as synchronization symbols added to transmission data by the mobile station.
During a time period in which communication with the mobile station and other base stations is performed at random, the synchronization symbol added to the transmission data by the mobile station as the known signal that takes a correlation value with the reception signal of each branch and the base station transmits the transmission data. The base station apparatus according to claim 2, wherein a synchronization symbol added to the base station is used. 4. A communication terminal device for performing wireless communication with the base station device according to claim 2. 5. When a plurality of branches receive an OFDM signal and calculate a correlation value with a known signal in a time zone for performing random communication with a mobile station or another base station, a predetermined branch is regarded as a known signal. The mobile station uses the synchronization symbol added to the transmission data, and for another predetermined branch, the synchronization symbol added to the transmission data by the base station as a known signal. The integrated value of the calculated correlation value is arbitrary. A method for acquiring synchronization, wherein a timing at which the integrated value of a branch exceeding a threshold value takes a maximum value is used as a symbol synchronization timing for all branches.