JPH06284120A - Radio receiver - Google Patents

Abstract

PURPOSE:To simply and surely detect a synchronizing signal even when noise is invaded or the like by detecting a correlation valve between a 1st correlation detection result and a correlation change pattern. CONSTITUTION:A synchronizing signal is formed by a predetermined bit pattern, the radio receiver demodulates a transmission signal to output reception data S and calculates a correlation value between the reception data S and the bit pattern for synchronizing signal detection, and detects a 1st correlation value detection result Y in which the reception data S rise in the vicinity of a timing when the synchronizing signal is outputted. Then the receiver executes multiplication between a data string DS segmenting the reception data S while shifting the bits one by one bit each and change detection data X of the correlation pattern stored in a ROM 23 and a predetermined arithmetic operation detects the correlation between the 1st correlation detection result Y and a correlation pattern D. Then a 2nd correlation detection result Z whose value rises in the timing when the 1st correlation detection result Y rises is detected and a timing of the synchronizing signal is detected based thereon.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Field of Industrial Application Conventional Technology (FIG. 5) Problem to be Solved by the Invention (FIG. 5) Means for Solving the Problem (FIGS. 1 to 4) Action (FIGS. 1 to 4) Example (1) Overall Configuration of Embodiment (FIG. 1) (2) Detection of FCCH (FIGS. 2 and 3) (3) Effect of Embodiment (4) Second Embodiment (FIG. 4) (5) Other Embodiment effect

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver, and can be applied to, for example, a digital cellular which encodes and transmits a voice signal.

[0003]

2. Description of the Related Art Conventionally, in a digital cellular telephone, which is one of radio telephones, by encoding and transmitting a voice signal, a time division multiplexing method is applied to simultaneously make one channel for a plurality of communication terminals. It is designed to be used.

That is, when the terminal device of this type is turned on, the preset 124 channels are sequentially scanned to detect the channel having the highest electric field strength.
As a result, the terminal device is assigned a BCCH (broadcast control channel) assigned to the area to which the terminal device belongs.
) Is detected and this BCCH is received.

The BCCH is adapted to form a time slot and transmit various kinds of information, whereby the digital cellular receives information of the base station which receives the BCCH at each terminal device and sends out the BCCH, which is adjacent to the information. The information of the base station, the calling information of the terminal device, and the like are transmitted. Therefore, the terminal device has an FCCH that is a synchronization signal output to the BCCH at a predetermined timing.
(Frequency correction channel) is detected, and the timing at which necessary information is transmitted is detected based on this FCCH, and the reception frequency is corrected based on this FCCH.

As a result, the terminal device is made to be able to talk to a desired communication target by detecting the call information from the base station and moving to the designated channel, and is compared with the BCCH reception result of the adjacent base station. Based on the results
Even if the BCCH to be received is switched so that the user moves to an adjacent area, a call can be surely made.

Therefore, the terminal device is adapted to detect the FCCH timing by applying the correlation detection method shown in FIG. That is, the terminal device receives the BCCH and obtains the serial data in the form of the received data S and the preset FCCH bit pattern C _k (FIGS. 5 (A) and 5 (B)), in sequence.

[Equation 1] The correlation value Y _n (Fig.
(C)) is detected. Here, N is the number of bits of the FCCH bit pattern C _k .

In case of digital cellular, this FCCH
Is assigned a bit pattern so that the data of the value "1" continues for a predetermined number of bits when demodulated, whereby the number of bits of the FCCH bit pattern C _k is set to this FC.
The received data S and F are set by setting the number of bits equal to that of CH and assigning a bit pattern of value "1".
The correlation value Y _n rises to the maximum value at the timing when the CCH bit patterns C _k completely match. As a result, the terminal device detects the timing at which the correlation value Y _n rises by the counter, and takes in the reception data S at a predetermined timing based on the timing detection result. Is synchronized (hereinafter referred to as frame synchronization) so that necessary information transmitted from the base station can be received.

[0009]

By the way, in this type of terminal device, it may be mounted on a vehicle and moved.
The electric field strength of CCH may change greatly. Further, not only the electric field strength of BCCH but also the signal level of noise may change significantly in the target signal. In addition, fading may occur, and in this case also, the electric field strength of BCCH changes greatly.

That is, the terminal device may have a large change in the E _b / N _o ratio due to the influence of noise or the like during reception, and when the FCCH is simply detected on the basis of the correlation value, the E When _b / N _o ratio becomes smaller, there has been a problem of erroneous detection of the FCCH. On the other hand, a method of detecting the slope of the change in the correlation value to detect the FCCH timing,
Further, there is a method of detecting the FCCH timing based on the result of comparison between a predetermined threshold value and the correlation value, but both of them have a problem of erroneously detecting the FCCH due to the influence of noise or the like.

When the FCCH is erroneously detected in this way, it becomes difficult to receive the necessary information, and the terminal device needs to detect the FCCH again and synchronize the frame, which makes it impossible to make a call promptly. The present invention has been made in view of the above points, and an object thereof is to propose a wireless reception device that can easily and reliably detect a synchronization signal of this type.

[0012]

According to the present invention, in order to solve such a problem, synchronization is achieved in a radio receiving apparatus 1 which receives a transmission signal with reference to a synchronization signal FCCH inserted in the transmission signal at a predetermined timing. The signal FCCH is
The wireless reception device 1 is formed with a predetermined bit pattern,
By detecting the correlation value Y between the receiving means 4, 6, 7, 8, 9 for demodulating the transmission signal and outputting the reception data S, and the reception data S and the bit pattern C _k for detecting the synchronization signal. , The first correlation value detection means 10 for detecting the first correlation value detection result Y whose value rises in the vicinity of the timing at which the synchronization signal FCCH is output to the reception data S, and the correlation with the first correlation value detection result Y By detecting the correlation value Z with the value change pattern D, the second correlation value for detecting the second correlation value detection result Z where the value rises at the timing when the value of the first correlation value detection result Y rises. And a synchronization signal FCC based on the second correlation detection result Z.
The timing of H is detected.

Further, in the second invention, the synchronization signal FC
The CH bit pattern is a fixed pattern in which data having a value of 0 or 1 is repeated by a predetermined number of bits, and the bit pattern C _k for detecting a synchronizing signal is a value of 0 corresponding to the fixed pattern.
Alternatively, the data of value 1 is formed by a part of the bit patterns of the synchronizing signal FCCH which is continuous by the number of bits shorter than the number of bits of the fixed pattern, and the first correlation detecting means 10 detects the received data S and the synchronizing signal. By detecting the correlation value Y with the bit pattern C _k for use in detection, the first correlation value detection result Y in which the value rises in a trapezoidal shape is detected in the vicinity of the timing when the synchronization signal FCCH is output to the reception data S. Then, the correlation value change pattern D is set such that the value is continuous in the trapezoidal shape, corresponding to the first correlation value detection result Y that rises in the trapezoidal shape.

Further, in the third invention, the first and second
Correlation value detection means 10 sequentially multiplies the change pattern detection data X having a predetermined correlation value by the reception data S, omits the first correlation value detection result Y, and directly outputs the second correlation value detection result Z.
To detect.

[0015]

The correlation value Y is detected between the received data S and the sync signal detection bit pattern C _k to obtain the first correlation value detection result Y, and the first correlation value detection result Y and the correlation value Y are obtained. By further detecting the correlation value Z with the change pattern D, the timing of the synchronization signal FCCH can be reliably detected even when noise is mixed.

Further, at this time, a bit pattern C _k for detecting the synchronizing signal is formed by a part of the bit patterns of the synchronizing signal FCCH, and the correlation value changing pattern is correspondingly formed so that the values continue in a trapezoidal shape. Set D,
The timing of the synchronization signal FCCH can be detected easily and reliably.

Further, the first correlation value detection result Y can be omitted and the second correlation value detection result Z can be directly detected, and the entire structure can be simplified accordingly.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

(1) Overall configuration of the embodiment In FIG. 1, reference numeral 1 denotes a digital cellular terminal device as a whole, in which a transmission signal transmitted from a base station is received by an antenna 2 and a reception signal obtained as a result is received by the antenna. Output to the mixer 4 via the duplexer 3. The mixer 4 frequency-converts the received signal using the local oscillation signal output from the oscillation unit 5, and then outputs the received signal via the filter 6, whereby the terminal device 1 switches the frequency of the local oscillation signal to a desired value. It is designed so that channels can be selectively received.

Analog digital conversion circuit (A / D) 7
Receives the output signal of the filter 6 through the amplifier circuit 8, converts it into a digital value with reference to a predetermined reference signal, and outputs the digital value, whereby the terminal device 1 is synchronized with the reference phase of the received signal. I data I which is the timing demodulation result
Is designed to be demodulated. Further, the analog digital conversion circuit 7 converts the output signal of the amplification circuit 8 into a phase shifter 9
Via the input signal and converts the input signal into a digital value, whereby the terminal device 1 can demodulate Q data Q which is a demodulation result having a phase difference of 90 degrees with respect to the I signal. The GMSK-modulated and transmitted I data and Q data can be demodulated.

The equalizer 10 removes the multipath by correcting the distortion of the I data and the Q data and outputs the data. The channel decoder 12 selectively selects the voice data from the output data of the equalizer 10 and outputs the voice decoder 13. Output to. As a result, the voice decoder 13
After demodulating the transmitted audio signal by converting it into data and Q data, the speaker 14 is driven.

As a result, the terminal device 1 can receive the voice signal transmitted from the call target via the base station. Further, the equalizer 10 detects the FCCH based on the I data and the Q data output from the analog digital conversion circuit 7, outputs the detection result to the central processing unit (CPU) 15, and the central processing unit 15
Controls the operations of the equalizer 10, the channel decoder 12, etc. based on the detection result.

As a result, the terminal device 1 receives the predetermined information transmitted from the base station on the basis of the FCCH detection result, and switches the frequency of the local oscillation signal based on the reception result, thereby performing a predetermined call. After switching the frequency to the channel, a predetermined time slot can be received to receive a voice signal.

On the other hand, in the transmission system of the terminal device 1, the audio signal output from the microphone 16 is sent to the voice encoder 17
After converting to voice data with, channel encoder 18
Is converted into I data and Q data. Further, the digital analog conversion circuit (D / A) 19 converts the I data and Q data into analog signals of I component and Q component,
The mixer 20 converts the analog signal of the I component and the Q component into a transmission signal of a predetermined frequency by using the local oscillation signal.

As a result, the terminal device 1 has the mixer 20.
Is output to the power amplifier 22 via the filter 21, and the output signal of the power amplifier 22 is transmitted from the antenna 2 via the antenna duplexer 3. At this time, the terminal device 1 switches the transmission and reception timings based on the predetermined timing detection result detected by the equalizer 10, thereby applying the time division multiplexing method to the base station from the plurality of terminal devices. The time slot assigned to the local station is selectively received from the transmitted signals transmitted by the local station, and the voice data is transmitted to the base station using the time slot assigned to the local station. .

(2) Detection of FCCH When the power of the terminal device 1 is turned on and the area to which the terminal device belongs is further switched, the central processing unit 15
The control data is sent to the oscillator 5 to receive the BCCH, and then the control data is output to the equalizer 10 to detect the FCCH. Here, the equalizer 10 sequentially receives the received data S input in the form of serial data and holds them for a predetermined period, thereby bit-shifting the continuous received data S by 1 bit and cutting out by a predetermined number M of bits.

Further, as shown in FIG. 2, the equalizer 10 multiplies the cut-out data string DS and the change pattern detection data X of the correlation pattern stored in the read only memory (ROM) 23 to obtain the following equation.

[Equation 2] The calculation processing of is executed. Here, the change pattern detection data X of the correlation pattern is expressed by the following equation.

[Equation 3] Therefore, in the case of this embodiment, the change in the correlation detection result Y is compared with the reference pattern D and the FCCH
It is designed to detect the timing of.

That is, as shown in FIG. 3, the number of bits of the FCCH and the number of bits of the FCCH bit pattern C _k are selected to match, and the received data S (FIG. 3A) and F
When the correlation value Y (FIG. 3 (C)) is sequentially detected with the CCH bit pattern C _k (FIG. 3 (B)), the correlation value changes into a mountain shape, and the peak timing of this correlation value is FCCH. Match the timing. However, in reality, when noise is mixed, the change in the correlation value changes into a mountain shape with the noise being superimposed as a whole.

On the other hand, the change in the correlation value is
The number of bits of FCCH and the number of bits of FCCH bit pattern C _k can be predicted in advance by the fact that H has a predetermined bit pattern (that is, a bit pattern in which the value “1” data is continuous). If they are selected so as to coincide with each other, the change pattern D _j of the correlation value as shown in FIG. _3D can be set. Thus once a predetermined period of data of the detected correlation value held to further correlation value Z between the change pattern D _j of the correlation values (Fig. 3
By detecting (E)), the FCCH timing can be detected based on the change in the correlation value Y.

In this case, the final correlation value Z can be rapidly raised at the FCCH timing as compared with the intermediate correlation value Y, whereby the FCCH timing can be reliably detected and the frame synchronization can be achieved. .

By the way, if this relationship is expressed by an equation,

[Equation 4] Can be expressed by the relational expression of

[Equation 5] The relational expression of can be obtained. Therefore, if this is transformed,

[Equation 6] Can be obtained, and by storing the change pattern detection data X of the correlation pattern represented by the equation (3) in the read-only memory 23 and multiplying it directly with the received data S, The two-step correlation value detection process can be executed by one multiplication process.

That is, instead of the conventional FCCH bit pattern, the change pattern detection data X of this pattern can be stored in the read-only memory 23 and the FCCH can be surely detected, whereby the frame synchronization can be surely performed with a simple structure. it can. Thus, when the FCCH is detected by the equalizer 10, the central processing unit 15 sets the time base counter built in the equalizer 10 and thereby fetches the received data S at a timing delayed by 8 slots from the FCCH.

As a result, the central processing unit 15 detects the SCH (synchronization channel) output from the base station at the timing delayed by the eight slots, receives the predetermined information sent from the base station, and receives the result. Control the whole operation based on.

(3) Effects of the Embodiments With the above configuration, the correlation value detection result is obtained between the FCCH bit pattern and the received data, and the correlation value is detected between the correlation value detection result and the reference pattern D. Then FCC
By detecting the timing of H, FCCH is surely
The timing of can be detected. Further, at this time, the correlation value is detected between the change detection data of the correlation pattern and the received data, and the two correlation value detection processes are executed by one multiplication process, thereby simplifying the entire configuration and ensuring that F
The CCH timing can be detected, and frame synchronization can be performed.

(4) Second Embodiment In this embodiment, the FCCH bit pattern C _k having a bit number shorter than that of the FCCH is used to form the FCCH.
The timing is detected and the entire configuration is simplified accordingly.

That is, as shown in FIG. 4, if the number of bits of the FCCH bit pattern C _k is set shorter than the number of bits of the FCCH, and the correlation value Y with the received data S (FIG. 4 (A)) is detected. (FIGS. 4B and 4C) Since the FCCH is formed by a continuous bit pattern with a value of "1", the detection result of the correlation value Y that changes into a trapezoidal shape can be obtained.

As a result, in this embodiment, the terminal device sets a reference pattern D having continuous trapezoidal values corresponding to the correlation value Y that changes to this trapezoidal shape (see FIG. 4).
(D)), the correlation value Z is detected between the reference pattern D and the correlation value Y. Thus, even if the correlation value Y is detected with reference to a part of the bit patterns of the FCCH, the reference pattern D corresponding to this bit length is set to detect the second correlation value Z. By doing
Correlation value Z that suddenly rises at FCCH timing
Can be detected, whereby the FCCH timing can be detected with certainty.

Further, even when the correlation value Z is detected with reference to a part of the bit patterns of the FCCH, by setting the change pattern detection data X of the correlation value, the same as in the first embodiment. The final correlation value Z can be detected by a single multiplication process, whereby the intermediate correlation value detection process can be omitted and the FCCH can be detected easily and reliably.

(5) Other Embodiments In the above embodiment, the case where the intermediate correlation value detection process is omitted by setting the correlation value change pattern detection data X has been described. Not limited to this, the first and second correlation value detection processing may be sequentially executed.

Further, in the above-mentioned embodiment, the case where the present invention is applied to digital cellular to detect the FCCH in which the data of the value "1" is continuous is described, but the present invention is not limited to this and various radios are used. The present invention can be widely applied to the case of receiving various data by detecting a synchronizing signal of a preset bit pattern applied to a receiving device.

[0041]

As described above, according to the present invention, the first correlation value detection result is obtained between the received data and the sync signal detection bit pattern, and the first correlation value detection result and the correlation value are obtained. By further detecting the correlation value with the change pattern, it is possible to obtain a wireless reception device that can easily and reliably detect the synchronization signal even when noise is mixed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a digital cellular terminal device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining the correlation detection.

FIG. 3 is a signal waveform diagram for explaining the operation.

FIG. 4 is a signal waveform diagram for explaining the operation of the second embodiment.

FIG. 5 is a signal waveform diagram for explaining conventional correlation detection.

[Explanation of symbols]

1 ... Terminal device, 2 ... Antenna, 4 ... Mixer, 6 ...
… Filters, 7… Analog digital conversion circuits, 10
…… Equalizer, 15 …… Central processing unit.

Claims (3)

[Claims] 1. A radio receiving apparatus for receiving the transmission signal with reference to a synchronization signal inserted in the transmission signal at a predetermined timing, wherein the synchronization signal is formed in a predetermined bit pattern. Is a receiving means for demodulating the transmission signal and outputting the reception data, and detecting the correlation value between the reception data and the bit pattern for detecting the synchronization signal to output the synchronization signal to the reception data. The correlation value between the first correlation value detection result and the correlation value change pattern. As a result, the second correlation value rises at the timing when the value of the first correlation value detection result rises.
And a second correlation value detecting means for detecting the correlation value detection result of 1., and detecting the timing of the synchronization signal based on the second correlation detection result. 2. The bit pattern of the synchronizing signal is a fixed pattern in which data of value 0 or 1 is repeated by a predetermined number of bits, and the bit pattern for detecting the synchronizing signal is a value 0 or a value corresponding to the fixed pattern. 1 data is formed by a part of bit patterns of the synchronizing signal bit pattern which is continuous by a number of bits shorter than the number of fixed pattern bits, and the first correlation detecting means detects the received data and the synchronizing signal. By detecting a correlation value with the bit pattern for use in detecting the first correlation value detection result in which the value rises in a trapezoidal shape in the vicinity of the timing at which the synchronization signal is output to the reception data, The correlation value change pattern is set such that the value is continuous in the trapezoidal shape, corresponding to the first correlation value detection result rising in the trapezoidal shape. Radio receiver according to claim 1, wherein. 3. The first and second correlation value detecting means directly multiply the change pattern detection data of a predetermined correlation value by the reception data, omitting the first correlation value detection result, and directly. The wireless receiving device according to claim 1 or 2, wherein the second correlation value detection result is detected.