JP2001197030A - Communication device, radio frame synchronizing method for communication device and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication device which simplifies a synchronizing processing procedure while suppressing an increase in the circuit scale of a preprocessor and a radio frame synchronizing method for the communication device and a recording medium. SOLUTION: For a frequency correction value calculated by a timing estimation part 103, an AFC part 106 controls a reference signal oscillator 107 with high precision and then a virtual radio frame counter 113 operates with the clock generated by a PLL circuit part 111, so the cycle of the virtual radio frame is always shorter than the cycle of the radio frame. For the purpose, a CPU 105 sets an offset value in an offset register 112 in the increasing direction of the cycle of the virtual radio frame according to the correction value received from the timing estimation part 103 through a RAM 104 to correct the virtual radio frame counter 113 in the direction wherein the cycle of the virtual radio frame increases, thereby synchronizing the virtual radio frames with the radio frames.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication apparatus, a radio frame synchronization method for the communication apparatus, and a recording medium on which a program for executing the radio frame synchronization method is recorded. The present invention relates to a communication apparatus, a wireless frame synchronization method for a communication apparatus, and a recording medium that perform wireless frame synchronization in communication by controlling only a correction amount and simplify a synchronization processing procedure while suppressing an increase in the circuit scale of a preprocessor.

[0002]

2. Description of the Related Art For example, TDMA (Time Division Multiple)
In iple Access (time division multiple access) communication, communication between each mobile station and the base station is performed by transmitting and receiving data in bursts using time slots in a radio frame allocated by the base station. . In order to prevent burst signals transmitted from each station from overlapping each other on a wireless line, it is necessary to control transmission timing. for that reason,
Each station has a common time reference, and sets transmission timing in consideration of the distance difference between each station and the receiving station. The former is called reception synchronization because a specific signal is detected from a received signal and used as a time reference, and the latter is called transmission synchronization because it determines the timing of a transmission signal.

In TDMA communication, a mobile station needs to synchronize its own transmission / reception radio frame timing with a base station so as not to collide with a burst signal of another station. In addition, since both the base station and mobile station have independent reference signals (having an oscillation frequency), how to achieve so-called subordinate synchronization that maintains synchronization while eliminating frequency deviation (timing error) between reference signals There is a problem of whether to do.

Generally, a radio frame created by a base station and a virtual radio frame created internally by a mobile station are generated from reference signals independent of each other (having an oscillation frequency). ) Also causes a phase error in the frame timing. Therefore, in the communication device on the mobile station side, it is necessary to correct a timing error between the base station and the communication device that occurs during a call. FIG. 4 shows the configuration of a conventional communication device that performs radio frame synchronization in communication with a base station.

In FIG. 4, a conventional communication device includes an antenna 201, a receiving unit 202, a timing estimating unit 203,
AM204, CPU205, AFC (Auto Frequency C
(control unit) 206, a reference signal oscillator 207, and a timing generator 208. The timing generation unit 208 includes a PLL unit 211, an offset register 212, and a virtual wireless frame counter 213 that is a free-running counter of 10 [ms].

The operation of synchronizing radio frames during communication in the conventional communication apparatus will be described below. First, a received signal received via the antenna 201 is
2 and is sent to the timing estimation section 203. The timing estimator 203 calculates a frequency correction value between the output signal of the reference signal oscillator 207 and the received signal from the base station, and passes the frequency correction value to the AFC section 206. Also,
The timing estimating unit 203 calculates a correction value between the wireless frame and the virtual wireless frame counter 213, and passes the correction value to the CPU 205 via the RAM 204.

[0007] The AFC section 206 controls the oscillation frequency of the reference signal oscillator 207 according to the frequency correction value, and supplies a reference signal synchronized with the base station radio frequency ± 0.1 [ppm] to the PLL section 211 of the timing generation section 208. I do. P
In the LL unit 211, the frequency 1 is set based on the supplied reference signal.
A signal having 6.384 [MHz] is generated. In addition, the virtual wireless frame counter 213 has a period of 10 [ms] (by 163840 counts) based on the signal of the frequency 16.384 [MHz] generated by the PLL unit 211.
Of virtual wireless frames are counted in free run.

[0008] Based on the correction value received via the RAM 204, the CPU 205 stores the virtual wireless frame counter 21 in the offset register 212 only once every 10 [ms].
The offset value of 3 and the increasing / decreasing direction of the correction are set. That is, the virtual wireless frame counter 213 synchronizes with the wireless frame every 10 [ms] according to the offset value set in the offset register 212 and the direction of increase / decrease of the correction. That is, the radio frame (10 [m
s]), the relationship between the virtual wireless frame (10 [ms]) and the offset value are as shown in FIG. 3, so that synchronization can be obtained depending on the offset value and the direction of increase / decrease of the correction.

[0009]

As described above, in the conventional communication apparatus and the radio frame synchronization method of the communication apparatus, the error between the radio wave from the base station and the reference signal oscillator can be shifted to either positive or negative. Therefore, in order to synchronize the virtual wireless frame with the wireless frame, it is necessary to set both the offset value and the direction of increase / decrease of the correction.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and performs radio frame synchronization in communication between a communication device and a base station by controlling only a correction amount, thereby increasing the circuit scale of a preprocessor. It is an object of the present invention to provide a communication device, a wireless frame synchronization method for a communication device, and a recording medium that perform wireless frame synchronization by simplifying a synchronization processing procedure while suppressing the synchronization.

[0011]

According to a first aspect of the present invention, there is provided a communication apparatus for receiving a radio wave from a base station and detecting a timing error between the base station and the communication apparatus. Detecting, and a timing estimating means for estimating a correction value of the oscillation frequency of the reference signal oscillator based on the timing error, based on the frequency correction value of the timing estimating means,
Frequency control means for controlling the oscillation frequency of the reference signal oscillator to be either a higher value or a lower value by a predetermined value, virtual radio frame timing means for counting based on the oscillation frequency of the reference signal oscillator, and the timing estimation Correction means for setting an offset value of the virtual wireless frame timing means based on the frequency correction value of the means so that the virtual wireless frame is corrected in one direction with respect to expansion and contraction of the period.

A communication device according to a second aspect is the communication device according to the first aspect, wherein the frequency control means includes:
The oscillation frequency of the reference signal oscillator is controlled to be higher by a predetermined value, and the correction unit corrects an offset value of the virtual wireless frame timing unit in a direction in which the virtual wireless frame extends or contracts in a cycle. Is set as follows.

According to a third aspect of the present invention, in the communication apparatus according to the first aspect, the frequency control means includes:
The oscillating frequency of the reference signal oscillator is controlled to be lower by a predetermined value, and the correcting unit corrects an offset value of the virtual wireless frame timing unit in a direction in which the virtual wireless frame contracts in terms of expansion and contraction of a period. It is set so that.

According to a fourth aspect of the present invention, there is provided a method for synchronizing a radio frame of a communication device, comprising the steps of: receiving a radio wave from a base station, detecting a timing error between the base station and the communication device; A timing estimating step of estimating a correction value of the oscillation frequency of the oscillator, and controlling the oscillation frequency of the reference signal oscillator to be either a higher value or a lower value by a predetermined value based on the frequency correction value of the timing estimation step. A frequency control step, a virtual radio frame timing step for counting based on an oscillation frequency of the reference signal oscillator, and an offset value of the virtual radio frame timing means based on a frequency correction value of the timing estimation step. A correction step of setting the expansion and contraction of the cycle to be corrected in one direction. That.

According to a fifth aspect of the present invention, in the wireless frame synchronizing method for a communication device according to the fourth aspect, the frequency control step includes setting the oscillation frequency of the reference signal oscillator to a predetermined value. The correction step sets the offset value of the virtual wireless frame timing step so as to correct the virtual wireless frame in a direction in which the virtual wireless frame expands and contracts with respect to the expansion and contraction of the period.

According to a sixth aspect of the present invention, in the wireless frame synchronization method for a communication apparatus according to the fourth aspect, the frequency control step includes setting the oscillation frequency of the reference signal oscillator to a predetermined value. And the correction step sets the offset value of the virtual wireless frame timing step so as to correct the virtual wireless frame in a direction to reduce the expansion and contraction of the period.

According to a seventh aspect of the present invention, there is provided a computer-readable recording medium storing a program for causing a computer to execute the wireless frame synchronization method for a communication device according to the fourth, fifth or sixth aspect. .

In the communication apparatus according to claims 1, 2 and 3 of the present invention, the radio frame synchronization method for the communication apparatus according to claims 4, 5 and 6, and the recording medium according to claim 7, the timing estimating means (timing Estimating step), receiving a radio wave from the base station, detecting a timing error between the base station and the communication device, estimating a correction value of the oscillation frequency of the reference signal oscillator based on the timing error, (Frequency control step), based on the frequency correction value of the timing estimation means (timing estimation step),
Control is performed so that the oscillation frequency of the reference signal oscillator becomes either a higher value or a lower value by a predetermined value. On the other hand, virtual wireless frame timing means (virtual wireless frame timing step)
Forms a virtual wireless frame by counting based on the oscillation frequency of the reference signal oscillator.
In the above, the offset value of the virtual wireless frame timing means (virtual wireless frame timing step) is set so that the virtual wireless frame is corrected in one direction for the expansion and contraction of the cycle based on the frequency correction value of the timing estimation means (timing estimation step). You have set.

In particular, in the communication apparatus according to the second aspect and the radio frame synchronization method for the communication apparatus according to the fifth aspect, the frequency control means (frequency control step) increases the oscillation frequency of the reference signal oscillator by a predetermined value. In the correction means (correction step), an offset value of the virtual wireless frame timing means (virtual wireless frame timing step) is set so that the virtual wireless frame is corrected in the direction in which the expansion and contraction of the cycle is extended. I have.

In particular, in the communication apparatus according to the third aspect and the radio frame synchronization method for the communication apparatus according to the sixth aspect,
The frequency control means (frequency control step) controls the oscillation frequency of the reference signal oscillator to be lower by a predetermined value, and the correction means (correction step) corrects the virtual wireless frame in a direction to reduce the expansion and contraction of the period. Thus, the offset value of the virtual wireless frame timing means (virtual wireless frame timing step) is set.

That is, if the frequency control means (frequency control step) controls the oscillation frequency of the reference signal oscillator to be higher by a predetermined value, the virtual radio frame timing means (virtual radio frame timing step) Since the virtual wireless frame is formed by counting based on the oscillation frequency of the oscillator, the counting speed of the virtual wireless frame timing means (virtual wireless frame timing step) always advances with respect to the wireless frame. The correction direction of (virtual wireless frame timing step) can be dealt with only in one direction in which the cycle of the virtual wireless frame extends.

Conversely, if the frequency control means (frequency control step) controls the oscillation frequency of the reference signal oscillator to be lower by a predetermined value, the virtual radio frame timing means (virtual radio frame timing step) Since the virtual wireless frame is formed by counting based on the oscillation frequency of the reference signal oscillator, the counting speed of the virtual wireless frame timing means (virtual wireless frame timing step) is always delayed with respect to the wireless frame. The correction direction of the timing means (virtual wireless frame timing step) can be dealt with only in one direction in which the period of the virtual wireless frame is shortened.

Therefore, according to the communication apparatus, the radio frame synchronization method of the communication apparatus, and the recording medium of the present invention, the radio frame synchronization in the communication between the communication apparatus and the base station can be performed by controlling only the correction amount. Therefore, the processing related to the bidirectional control can be simplified, so that the internal circuit of the preprocessor can be used effectively. As a result, it is possible to realize a communication apparatus and a wireless frame synchronization method for a communication apparatus capable of performing wireless frame synchronization by simplifying the synchronization processing procedure while suppressing an increase in the circuit scale of the preprocessor.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a communication device, a radio frame synchronization method for a communication device, and a recording medium according to the present invention will be described in detail with reference to the drawings. In the description of each embodiment, the communication device according to the present invention and the wireless frame synchronization method of the communication device will be described in detail. However, for the recording medium according to the present invention, a program for executing the wireless frame synchronization method is provided. The description is included in the following description of the radio frame synchronization method because the recording medium is a recorded recording medium.

[Embodiment] FIG. 1 is a configuration diagram of a communication apparatus according to an embodiment of the present invention. The configuration in the figure is
Only the part related to wireless frame synchronization in the communication device is shown. In FIG. 1, a communication device according to the present embodiment includes an antenna 101, a receiving unit 102 for demodulating radio waves from a base station, a timing estimating unit 103 for measuring an error correction with respect to a radio frame, a RAM 104, An AFC (Au) for synchronizing the CPU 105 for controlling the timing with the frequency of the base station radio wave and the reference signal oscillator 107
to Frequency Control) unit 106,
It comprises a reference signal oscillator 107 for oscillating a reference signal, and a timing generator 108 for synchronizing radio frames. Further, the timing generation unit 108
(Phase-Locked Loop) unit 111,
The configuration includes an offset register 112 and a virtual wireless frame counter 113 which is a free-running counter of 10 [ms].

In the state of communication with the base station, the receiving section 102 of the communication apparatus of the present embodiment receives a radio wave from the base station via the antenna 101 and demodulates it.

The receiving section 102 and the timing estimating section 103 correspond to timing estimating means described in the claims. The timing estimating section 103 detects a timing error between the base station and the communication apparatus, A correction value of the oscillation frequency of the reference signal oscillator 107 is estimated based on the error. FIG. 2 shows, as frame configurations in the communication apparatus of the present embodiment, a superframe (see FIG. 2B), a radio frame (see FIG. 2C), and a dedicated physical channel (see FIG. 2D). An example is shown. In the timing estimating unit 103, the first four symbols (pilot symbols) of the dedicated physical channel as shown in FIG.
, A frequency correction value (± 0.1 [ppm]) between the base station radio wave and the reference signal oscillator 107 is calculated, and the AFC unit 10
Send to 6.

Next, the AFC unit 106 corresponds to a frequency control unit, and based on the frequency correction value of the timing estimating unit 103, the oscillation frequency of the reference signal oscillator 107 becomes either a higher value or a lower value by a predetermined value. Control. Here, the frequency correction value (± 0.1 [ppm]) specified by timing estimation section 103 is +0.16 [pp].
[m] with an accuracy of [m].

Therefore, the reference signal oscillator 107
A reference signal having a frequency of [MHz] is output, and the accuracy of the oscillation frequency is from +0.06 [ppm] to +0.26 [pp
m]. The reference signal is a signal from which a clock for moving the virtual wireless frame counter 113 is generated in the timing generation unit 108, and has a frequency of +0.06.
A reference signal having an accuracy of [ppm] to +0.26 [ppm] is supplied to the timing generation unit 108.

In the timing generator 108, the PLL
The unit 111 converts the frequency 15 [MHz] to +0.06 [pp
A clock having a frequency of 16.384 [MHz] is generated based on a reference signal having an accuracy of [m] to +0.26 [ppm]. Virtual wireless frame counter for forming a virtual wireless frame of the communication device (virtual wireless frame counting means)
Since the counter 113 performs counting based on this clock, the cycle of the virtual wireless frame is always shorter than the cycle of the wireless frame.

Next, the CPU 105 and the offset register 112 correspond to correction means,
The offset value of the virtual wireless frame counter 113 is set such that the virtual wireless frame is corrected in one direction with respect to the expansion and contraction of the cycle based on the frequency correction value. Specifically, the CPU 105 receives a correction value of a timing error with respect to the base station from the timing estimating unit 103 via the RAM 104. The CPU 105 corrects the virtual wireless frame counter 113 in the direction in which the period of the virtual wireless frame is extended by setting the offset value in the offset register 112 in the direction in which the period of the virtual wireless frame is extended, based on the correction value. The radio frame can be synchronized with the radio frame.

In FIG. 1, the timing estimator 1
03, the RAM 104, the CPU 105, the AFC unit 106, and the timing generation unit 108 can be realized by a DSP (signal processing processor). In this case, the wireless frame synchronization method of the communication device according to the present embodiment is realized by a program executed on the DSP.

Here, the wireless frame synchronization method of the communication device can be summarized as follows.
Receiving a radio wave from the base station, detecting a timing error between the base station and the communication device, estimating a correction value of the oscillation frequency of the reference signal oscillator 107 based on the timing error; Is controlled so that the oscillation frequency of the reference signal oscillator 107 becomes higher by a predetermined value. on the other hand,
In the virtual wireless frame timing step, the reference signal oscillator 1
A virtual wireless frame is formed by counting based on the oscillation frequency of 07, and in the correcting step, the virtual wireless frame timing is adjusted so that the period of the virtual wireless frame is extended based on the frequency correction value of the timing estimation step. Set the step offset value.

As described above, according to the communication apparatus and the radio frame synchronization method of the communication apparatus of the present embodiment, first,
The AFC unit 106 controls the reference signal oscillator 107 with high accuracy of +0.16 [ppm] with respect to the frequency correction value calculated by the timing estimation unit 103. Since the virtual wireless frame counter 113 operates with the clock generated by the PLL unit 111, the cycle of the virtual wireless frame formed by the virtual wireless frame counter 113 is always shorter than the cycle of the wireless frame. Therefore, the CPU 105 sets the offset value in the direction in which the cycle of the virtual wireless frame is extended based on the correction value received from the timing estimation unit 103 via the RAM 104 in the offset register 1.
12, the virtual wireless frame counter 11
3 can be corrected in the direction in which the cycle of the virtual wireless frame is extended, and the virtual wireless frame can be synchronized with the wireless frame.

The difference between the communication apparatus of this embodiment and the method of synchronizing the radio frame of the communication apparatus from the related art is that the AFC unit 10
6 to adjust the oscillation frequency to be high by adjusting the reference signal oscillator 107,
Since the counting speed of the virtual wireless frame counter 113 operated by the clock generated by the PLL unit 111 based on the output signal of the virtual wireless frame counter 113 can always be made to advance with respect to the wireless frame, the correction direction of the virtual wireless frame counter 113 Can be handled only in one direction in which the period of the virtual wireless frame is extended.

Therefore, according to the communication apparatus and the radio frame synchronization method of the communication apparatus of the present embodiment, the radio frame synchronization in the communication between the communication apparatus and the base station can be performed by controlling only the correction amount. Therefore, the processing related to the bidirectional control can be simplified, so that the internal circuit of the preprocessor can be used effectively. as a result,
A communication device and a wireless frame synchronization method for a communication device capable of simplifying a synchronization processing procedure and performing wireless frame synchronization while suppressing an increase in the circuit scale of the preprocessor can be realized.

[Modification of Embodiment] In the above description of the communication apparatus and the radio frame synchronization method of the communication apparatus according to the present embodiment, the AFC unit 106 uses the reference signal oscillator 1
07 is controlled so as to be higher by a predetermined value, and the offset value of the virtual wireless frame counter 113 is set in the offset register 112 by the CPU 105 so that the virtual wireless frame period is corrected in the extending direction. Alternatively, the reverse may be performed.

That is, the AFC unit 106 controls the oscillation frequency of the reference signal oscillator 107 to a lower value by a predetermined value, and the CPU 105 controls the virtual radio frame so that the period of the virtual radio frame is shortened. The offset value of the counter 113 is stored in the offset register 1
It is set to 12. Specifically, the AFC unit 106
Is set to −0.16 [ppm] with respect to the designated correction value, and the offset value of the virtual wireless frame counter 113 is set in the offset register 112 in a direction in which the period of the virtual wireless frame is shortened. In this way, the correction direction of the virtual wireless frame counter 113 can be handled only in one direction in which the period of the virtual wireless frame is reduced, and the communication between the communication device and the base station is performed in the same manner as in the above-described embodiment. Wireless frame synchronization in communication can be performed by controlling only the correction amount.

[0039]

As described above, according to the communication device, the radio frame synchronization method of the communication device, and the recording medium of the present invention, the timing estimating means (timing estimating step) receives the radio wave from the base station. A timing error between the base station and the communication device is detected, a correction value of the oscillation frequency of the reference signal oscillator is estimated based on the timing error, and frequency control means (frequency control step)
On the basis of the frequency correction value of the timing estimating means (timing estimating step), the oscillation frequency of the reference signal oscillator is controlled so as to be either a higher value or a lower value by a predetermined value. Setting an offset value of the virtual wireless frame timing means (virtual wireless frame timing step) so that the virtual wireless frame is corrected in one direction with respect to expansion and contraction of the period based on the frequency correction value of the means (timing estimation step); As a result, the radio frame synchronization in the communication between the communication device and the base station can be performed by controlling only the correction amount. As a result, the radio frame synchronization can be simplified by suppressing the increase in the circuit scale of the preprocessor and simplifying the synchronization processing procedure. Device and a method of synchronizing radio frames of the communication device capable of performing .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a communication device according to an embodiment of the present invention.

FIGS. 2A and 2B are explanatory diagrams illustrating a frame configuration in the communication apparatus according to the embodiment; FIG. 2A is a frame configuration, FIG. 2B is a superframe configuration, FIG.
(D) shows individual physical channels.

FIG. 3 is an explanatory diagram illustrating a relationship between a radio frame, a virtual radio frame, and an offset value;

FIG. 4 is a configuration diagram of a conventional communication device that performs radio frame synchronization in communication with a base station.

[Explanation of symbols]

 Reference Signs List 101 antenna 102 reception unit 103 timing estimation unit 104 RAM 105 CPU 106 AFC unit 107 reference signal oscillator 108 timing generation unit 111 PLL unit 112 offset register 113 virtual wireless frame counter

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (7)

[Claims] 1. A timing estimating means for receiving a radio wave from a base station, detecting a timing error between the base station and the communication device, and estimating a correction value of an oscillation frequency of a reference signal oscillator based on the timing error. A frequency control unit that controls the oscillation frequency of the reference signal oscillator to be either a higher value or a lower value by a predetermined value based on the frequency correction value of the timing estimating unit, and based on the oscillation frequency of the reference signal oscillator. Virtual wireless frame timing means for counting; and correction for setting an offset value of the virtual wireless frame timing means based on a frequency correction value of the timing estimating means so that the virtual wireless frame is corrected in one direction for expansion and contraction of a cycle. Means for communication. 2. The frequency control means controls the oscillation frequency of the reference signal oscillator to a value higher by a predetermined value, and the correction means sets the offset value of the virtual radio frame timing means to the virtual radio frame 2. The communication device according to claim 1, wherein the communication device is set so as to be corrected in a direction in which the expansion and contraction of the cycle are extended. 3. The frequency control means controls the oscillation frequency of the reference signal oscillator to a value lower by a predetermined value, and the correction means sets the offset value of the virtual radio frame timing means to the virtual radio frame. 2. The communication device according to claim 1, wherein the communication device is set so as to be corrected in a direction to shorten the expansion and contraction of the period. 4. A timing estimating step of receiving a radio wave from a base station, detecting a timing error between the base station and the communication device, and estimating a correction value of an oscillation frequency of a reference signal oscillator based on the timing error. Based on the frequency correction value of the timing estimation step,
A frequency control step of controlling the oscillation frequency of the reference signal oscillator to be either a higher value or a lower value by a predetermined value; a virtual radio frame timing step of counting based on the oscillation frequency of the reference signal oscillator; and the timing estimation. Based on the frequency correction value of the step,
A correction step of setting an offset value of the virtual wireless frame timing means so that the virtual wireless frame is corrected in one direction with respect to expansion and contraction of a cycle. 5. The frequency control step controls the oscillation frequency of the reference signal oscillator to a value higher by a predetermined value, and the correction step sets the offset value of the virtual radio frame timing step to the virtual radio frame The wireless frame synchronization method for a communication device according to claim 4, wherein the setting is made so that the correction is made in the direction of extending the expansion and contraction of the cycle. 6. The frequency control step controls the oscillation frequency of the reference signal oscillator to a value lower by a predetermined value, and the correction step sets the offset value of the virtual radio frame timing step to the virtual radio frame 5. The wireless frame synchronization method for a communication device according to claim 4, wherein the setting is made such that the correction is made in a direction to shorten the expansion and contraction of the period. 7. A computer-readable recording medium stored as a program for causing a computer to execute the wireless frame synchronization method for a communication device according to claim 4, 5 or 6.