JP5419129B2 - COMMUNICATION SYSTEM AND SYNCHRONIZATION METHOD, BASE STATION DEVICE - Google Patents

Description

  The present invention relates to a communication system, a synchronization method, and a base station apparatus in which a plurality of base station apparatuses are synchronized to transmit information to a wireless terminal connected to the apparatus.

Conventionally, a synchronization signal is transmitted and received between a terminal apparatus and a base station apparatus that are connected for communication by radio, and signals are synchronized between the terminal apparatus and the base station apparatus using this synchronization signal. This synchronization signal is also used when a plurality of base station apparatuses are controlled so as not to transmit data at the same timing to terminal apparatuses connected to the own apparatus. Patent Document 1 discloses a control technique for synchronizing time so that a synchronization signal is not transmitted at the same time as a synchronization signal transmitted by another base station apparatus. In addition, the base station apparatus sets a rank indicating the accuracy of the synchronization signal, and based on the synchronization signal of the base station apparatus in which a higher rank is set than the floor set in the own base station apparatus, the time A technique for controlling synchronization is disclosed in Patent Document 2.
Japanese Patent No. 2993469 JP-A-5-308334

  Here, Patent Document 2 discloses that time synchronization control between base station apparatuses is performed based on a synchronization signal transmitted from another base station apparatus. However, in the technique of Patent Document 2, if the accuracy of time synchronization of the base station device itself that transmitted the synchronization signal is not high, there are many base station devices, and transmission is performed from the base station device that is a reference for time synchronization. Time synchronization of the base station apparatus existing at a position where the received synchronization signal cannot be received is delayed, and the accuracy of time synchronization is lowered as a whole.

  Therefore, an object of the present invention is to provide a communication system, a synchronization method, and a base station apparatus that can improve the accuracy of time synchronization between base station apparatuses.

In order to achieve the above object, the present invention provides a communication system in which each of a plurality of base station apparatuses transmits information to a radio terminal connected to the base station apparatus in synchronization with each other. This is a synchronization signal for synchronization in the apparatus, and relates to the time when the transmission source base station apparatus performed the synchronization processing as first synchronization accuracy index information that can specify the accuracy of the synchronization time in the transmission source base station apparatus The synchronization signal receiving means for receiving the synchronization signal storing the information, and the information related to the time when the own apparatus performed the synchronization process is stored as the second synchronization accuracy index information that can specify the accuracy of the synchronization time when the own apparatus is synchronized. When the accuracy of the synchronization time specified by the synchronization accuracy index information storage means and the first synchronization accuracy index information is better than the accuracy of the synchronization time specified by the second synchronization accuracy index information, A synchronization unit that corrects a timing for transmitting the synchronization signal from the own device based on a reference time stored in the synchronization signal storing the first synchronization accuracy index information. .

  According to the present invention, in the communication system described above, the synchronization signal receiving unit receives a synchronization signal transmitted from another plurality of base station apparatuses, and the synchronization unit is a first unit that indicates the most accurate synchronization time. The timing for transmitting the synchronization signal from the own apparatus is corrected based on the reference time stored in the synchronization signal in which the synchronization accuracy index information is stored.

Further, the present invention provides a communication system in which each of a plurality of base station devices synchronizes and transmits information to a wireless terminal connected to the device, and the base station device is configured to synchronize with the plurality of base station devices. a synchronizing signal, a synchronizing signal that stores information about the time of performing the Oite synchronization to the base station apparatus of the transmission source, a synchronization signal receiving means for receiving from a plurality of other base stations, the other Weighting according to the time at which the synchronization processing was performed for each difference between the most accurate synchronization reference time among the synchronization reference times stored in the synchronization signals transmitted from the plurality of base station apparatuses and other synchronization reference times And a synchronization unit that corrects the timing of transmitting a synchronization signal from the device based on the average.

  In the communication system described above, the layer value obtained by adding 1 to the layer value indicating the layer of the synchronization source given to the base station apparatus that is the transmission source of the synchronization signal is added to the received synchronization signal. And the synchronization means weights the difference based on a layer value in the synchronization signal used for calculation of the difference, and weights the difference higher as the layer value is higher. The timing for transmitting the synchronization signal from the own apparatus is corrected based on the average of the differences.

Further, the present invention is a synchronization method of a communication system in which each of a plurality of base station apparatuses synchronizes and transmits information to a wireless terminal connected to the own apparatus, and the synchronization signal receiving means of the base station apparatus A synchronization signal for synchronization in a plurality of base station devices, and the transmission source base station device performs synchronization processing as first synchronization accuracy index information that can specify the accuracy of synchronization time in the transmission source base station device. The synchronization signal storing information related to the performed time is received, and the synchronization accuracy index information storage means of the base station apparatus is used as second synchronization accuracy index information that can specify the accuracy of the synchronization time at which the apparatus is synchronized. There stores information about the time of performing the synchronization process, the synchronization means of the base station apparatus, time synchronization accuracy specified by the first synchronization accuracy index information is specified by the second synchronization accuracy index information When the accuracy of the synchronization time is better, the timing for transmitting the synchronization signal from the own device is corrected based on the reference time stored in the synchronization signal storing the first synchronization accuracy index information. It is a synchronization method.

Further, the present invention is a synchronization method of a communication system in which each of a plurality of base station apparatuses synchronizes and transmits information to a wireless terminal connected to the own apparatus, and the synchronization signal receiving means of the base station apparatus a synchronization signal for synchronizing a plurality of base station devices, the synchronization signal containing information about the time of performing the Oite synchronization to the base station apparatus of the transmission source, from the other plurality of base stations receiving, synchronizing means of the base station apparatus, the most accurate synchronization reference time and other synchronization reference time of the synchronization reference time stored in the synchronization signal transmitted from said other plurality of base stations The synchronization method is characterized in that the timing at which the synchronization signal is transmitted from the own apparatus is corrected based on the weighted average of each difference in accordance with the time at which the synchronization processing is performed .

The present invention is also a base station device of a communication system in which each of a plurality of base station devices synchronizes and transmits information to a radio terminal connected to the device, and the plurality of base station devices are synchronized with each other. A synchronization signal in which information about the time at which the transmission source base station apparatus performed the synchronization processing is stored as first synchronization accuracy index information that can specify the accuracy of the synchronization time in the transmission source base station apparatus. The synchronization signal receiving means for receiving the synchronization signal and the synchronization accuracy index information storage means for storing the information related to the time when the own apparatus performed the synchronization process as the second synchronization accuracy index information capable of specifying the accuracy of the synchronization time at which the own apparatus is synchronized When the accuracy of the synchronization time specified by the first synchronization accuracy index information is better than the accuracy of the synchronization time specified by the second synchronization accuracy index information, the first synchronization accuracy index information Based on the reference time stored in the storing synchronization signal, a base station apparatus characterized by comprising: a synchronization means for correcting the timing of transmitting a synchronization signal from the own apparatus.

The present invention is also a base station device of a communication system in which each of a plurality of base station devices synchronizes and transmits information to a radio terminal connected to the device, and the plurality of base station devices are synchronized with each other. of a synchronizing signal, a synchronizing signal that stores information about the time of performing the Oite synchronization to the base station apparatus of the transmission source, a synchronization signal receiving means for receiving from a plurality of other base station apparatus, the other In accordance with the time at which the synchronization processing was performed for each difference between the most accurate synchronization reference time among the synchronization reference times stored in the synchronization signals transmitted from the plurality of base station apparatuses and other synchronization reference times A base station apparatus comprising: synchronization means for correcting timing for transmitting a synchronization signal from the own apparatus based on a weighted average.

 According to the present invention, the base station device 1 can match the synchronization accuracy (start time of the basic frame) with another base station device with good synchronization accuracy. Then, since the base station apparatus that has performed the synchronization process stores the start timing of the basic frame transmission period from the time, the base frame transmission period starts based on the newly set basic frame start time. To detect. As a result, the transmission time of the synchronization signal and the transmission time of the subsequent communication data in the basic frame transmission period can be transmitted with high accuracy, so that they do not collide with the synchronization signal and communication data transmitted from other base station devices. A synchronization signal and communication data from the own device can be transmitted to the terminal device.

Hereinafter, a communication system according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a communication system according to the embodiment.
In this figure, reference numeral 1 is a base station apparatus, and 2 is a terminal apparatus that performs wireless communication with the base station apparatus 1. In this figure, the three base station devices 1 of the base station devices 1a to 1c are connected to the management server 3 through a wireless or wired communication network, and the synchronization signals transmitted from the respective base station devices 1a to 1c. Are transmitted to the terminal apparatuses 2a to 2c connected to the respective base station apparatuses.

FIG. 2 is a functional block diagram of the base station apparatus 1 of FIG.
The base station apparatus 1 includes a radio reception unit 11, a control unit 12, a clock unit 13, a synchronization signal detection unit 14 (synchronization signal reception unit), a synchronization timing signal generation unit 15, a timing determination unit 16 (synchronization unit), and a synchronization signal generation. Unit 17 and wireless transmission unit 18.

FIG. 3 is a functional block diagram of the synchronization timing signal generator 15 of FIG.
The synchronization timing signal generation unit 15 includes a synchronization accuracy index detection unit 151, a synchronization accuracy index comparison unit 152, a synchronization accuracy index storage unit 153 (synchronization accuracy index information storage unit), and a synchronization processing instruction unit 154.

  The base station device 1 stores the first synchronization accuracy index information that can specify the accuracy of the synchronization time in the transmission source base station device, receives a synchronization signal for synchronizing with each other in a plurality of base station devices, Send yourself. In addition, the base station apparatus 1 stores second synchronization accuracy index information that can specify the accuracy of the synchronization time at which the device is synchronized. Then, when the accuracy of the synchronization time specified by the first synchronization accuracy indicator information is better than the accuracy of the synchronization time specified by the second synchronization accuracy indicator information, the base station apparatus 1 Is corrected based on the reference time in the synchronization signal in which the synchronization signal is stored. Details of the processing of each processing unit will be described later.

Next, processing of the base station apparatus 1 in the communication system of the present invention will be described with reference to FIGS. FIG. 4 is a diagram showing a processing outline of the synchronization signal transmission processing.
First, each of the base station devices 1a to 1c transmits the synchronization signal S based on the transmission order Si notified in advance from the management server 3 or the like. The base station devices 1a to 1c receive the information of the transmission order Si from the management server 3 in the wireless reception unit 11, and the control unit 12 detects the number of the transmission order Si of its own device and records it in a memory or the like. Keep it. Then, each of the base station devices 1a to 1c transmits the synchronization signals Sa to Sc in order according to the transmission order Si received from the management server 3. Here, each base station apparatus 1a-1c can receive the synchronizing signal transmitted from each other base station apparatus. For example, the base station device 1a receives the synchronization signals Sb and Sc from the base station devices 1b and 1c. And each base station apparatus 1a-1c performs the process which correct | amends the transmission timing of the synchronizing signal S transmitted from an own apparatus based on the synchronizing signal S transmitted from the other base station apparatus.

  As shown in FIG. 4, there are a synchronization period St and a data period Dt within the basic frame transmission period Ft, and the base station apparatuses 1a to 1c transmit synchronization signals Sa to Sc to the terminal apparatus 2 during the synchronization period St. In the period Dt, the terminal device 2 transmits communication data Da to Dc used for processing to the terminal device 2. Further, in the synchronization period St, the synchronization signal transmission timing Ts at which the synchronization signal S can be transmitted is divided and set, and the base station devices 1a to 1c are among the plurality of synchronization signal transmission timings Ts in the synchronization period St. The synchronization signal S is transmitted at the synchronization signal transmission timing Ts corresponding to the transmission order Si received from the management server 3. For example, in FIG. 4, the base station apparatus 1b receives the transmission order No. 2 and transmits the synchronization signal Sb at the second synchronization signal transmission timing Ts2 within the synchronization period St. In the present embodiment, the synchronization processing means that the basic frame start time Ta ′ stored in the own apparatus is added to the basic frame start time Ta indicating the rising edge of the basic frame transmission period Ft set in the other base station apparatus 1. To match. By this synchronization processing, the transmission period of the synchronization signal S and communication data D transmitted from the other base station apparatus 1 and the transmission period of the synchronization signal S and communication data D transmitted from the own apparatus are controlled. This synchronization process is a process performed by a base station apparatus other than the reference base station apparatus, and the reference base station apparatus is synchronized with the time notified from the management server 3. Note that a reference station device serving as a reference is selected by the management server 3, and information on which base station device is used as a reference is transmitted from the management server 3 to base station devices other than the reference.

(First embodiment)
Next, a first embodiment of the synchronization processing of the base station apparatus will be described with reference to FIGS.
FIG. 5 is a diagram showing a flow of synchronization processing of the base station apparatus according to the first embodiment, FIG. 6 is a diagram showing a processing outline of synchronization signal transmission processing, and FIGS. 7 and 8 show communication states between the base station devices. FIG. 9 is a schematic diagram showing the synchronization processing time of the base station apparatus.
Here, the operation of the base station apparatus 1d will be described on the assumption that the base station apparatus 1a is a base station apparatus as a reference. First, the radio reception unit 11 of the base station device 1d receives synchronization signals from the other base station devices 1a, 1b, and 1c during the synchronization period St shown in FIG. 6 (step S101), and the synchronization signal detection unit 14 This is detected (step S102).
Next, the base station device 1d determines whether or not it has received synchronization signals from all other base station devices (step S103). Since the synchronization period St is a period in which all base station apparatuses transmit the synchronization signal S, a plurality of synchronization signals received during that period are transmitted from all of the other base station apparatuses located within the receivable range. The synchronization signal may be used.

Next, the base station apparatus 1d determines whether or not the received synchronization signal includes the synchronization signal Sa from the base station apparatus 1a serving as a reference (step S104). As shown in FIG. 7, if the base station apparatus 1a is included in the receivable range 200d of the base station apparatus 1d and the synchronization signal Sa can be received, the synchronization signal Sa is added to the synchronization signal received by the base station apparatus 1d. Is included. In this case, the base station device 1d acquires the synchronization signal Sa from the base station device 1a, and corrects its own synchronization timing based on the synchronization signal Sa (step S109).
On the other hand, as shown in FIG. 8, there is a state in which the base station device 1a is not included in the receivable range 200d ′ of the base station device 1d, or the reference synchronization signal Sa is not transmitted due to a trouble of the base station device 1a. is there.
In the present embodiment, the synchronization signal S transmitted from each base station apparatus 1 also stores the synchronization accuracy index value (first synchronization accuracy index information). This synchronization accuracy index value represents the synchronization accuracy of the start time Ta of the basic frame Ft in each base station apparatus 1 that has transmitted the synchronization signal S. The synchronization accuracy can be expressed by various indexes. Here, the time at which each base station apparatus 1 performs the synchronization process is stored, and the base station apparatus that has performed the synchronization process at a more recent time is synchronized. It is determined that the base station apparatus is accurate. That is, the synchronization accuracy index value is the synchronization time itself, and it is assumed that the synchronization accuracy is higher as the time when the synchronization processing is performed is more recent. In this case, the synchronization signal S also stores the base station ID of the base station apparatus 1 that has transmitted the synchronization signal S and the start time Ta of the basic frame Ft that the base station apparatus 1 has set in its own apparatus through synchronization processing. It is assumed that Then, the synchronization signal detection unit 14 records the base station ID, the synchronization accuracy index value, and the start time Ta of the basic frame Ft that are stored in the detected synchronization signal S in association with each other in a memory or the like.

Each base station apparatus 1 stores its own apparatus synchronization accuracy index value (second synchronization accuracy index information) in its own memory (synchronization accuracy index storage unit 153). The own device synchronization accuracy index value is a synchronization time at which the own device performs the synchronization process.
When it is determined in step S104 that the received synchronization signal does not include the synchronization signal Sa of the reference base station apparatus 1a, the synchronization signal detection unit 14 notifies the synchronization timing signal generation unit 15 of the detected synchronization signal S. . Next, the synchronization timing signal generation unit 15 detects the synchronization accuracy index value from the synchronization signal S received by the synchronization accuracy index detection unit 151. Then, the synchronization accuracy index comparison unit 152 has its own device synchronization accuracy index value recorded in advance in the synchronization accuracy index storage unit 153 and the synchronization accuracy index value stored in the synchronization signal S received from another base station device. Are compared by the synchronization accuracy index comparison unit 152 (step S105). For example, if the synchronization accuracy index value is information on the time at which the synchronization processing is performed, the time at which the own device indicated by the own device synchronization accuracy index value performs the synchronization processing, and another base stored in the received synchronization signal It is compared with the time when the station apparatus performed the synchronization process, and it is determined which time is closer to the current time (step S106).

  In this case, if the time indicated by the own apparatus synchronization accuracy index value is closer to the current time than the time indicated by the synchronization accuracy index value stored in the synchronization signal S received from another base station apparatus, the synchronization accuracy of the own apparatus Judge that is better. On the other hand, if the time indicated by the synchronization accuracy index value of the own device is later than the time indicated by the synchronization accuracy index value stored in the synchronization signal S received from another base station device, the synchronization accuracy of the own device is more accurate. Judge that it is bad.

  Assuming that the base station device 1d is its own device and the base station devices 1b and 1c are other base station devices, as shown in FIG. 9, the synchronization accuracy index included in the synchronization signals Sb and Sc of the base station devices 1b and 1c. The synchronization times Tb and Tc that are values are detected, the synchronization time Td that is the own device synchronization accuracy index value is read, and the current time T1 is compared with each synchronization accuracy index value Tb, Tc, and Td. Since the synchronization accuracy index value Tb of the base station device 1b is later than the current time T1 with respect to the own device synchronization accuracy index value Td, the synchronization accuracy of the base station device 1d that is the own device is It is determined that the base station apparatus 1b is better and the base station apparatus 1b is worse than the base station apparatus 1d. On the other hand, since the synchronization accuracy index value Tc of the base station device 1c is closer to the current time T1 than the synchronization accuracy index value Td of the own device, the synchronization accuracy of the base station device 1d that is the own device is more It is determined that the base station device 1c is better than the base station device 1d, worse than the station device 1b. That is, in the example shown in FIG. 9, it is assumed that the synchronization accuracy is good in the order of base station apparatuses 1c> 1d> 1b.

  Then, the synchronization processing instructing unit 154 has the most accurate base station device (the base time at which the synchronization time indicated by the synchronization accuracy index value is closer to the current time among the base station devices 1 having higher accuracy than the synchronization accuracy of the own device. In the example of FIG. 9, the base station ID of the base station device 1c is detected from the synchronization signal Sc. Also, the synchronization processing instruction unit 154 acquires the start time Tac of the basic frame Ftc stored in the synchronization signal Sc (step S107). Then, the synchronization processing instruction unit 154 transmits the synchronization signal Sc storing the base station ID of the base station device 1c and the start time Tac of the basic frame Ftc set by the synchronization processing by the base station device 1c to the timing determination unit 16. Thus, the timing determination unit 16 is instructed to start the synchronization process.

  The timing determination unit 16 receives the clock signal counted by the clock unit 13. The start time Ta of the basic frame transmission period Ft as shown in FIG. 6 and the transmission timing of the synchronization signal S within the basic frame transmission period Ft are stored in advance in a memory or the like. For example, it is assumed that the basic frame transmission period Ft is repeated in units of 60 msec (milliseconds), and the synchronization period St is 5 msec. Also, in the synchronization period St, the timing for transmitting the synchronization signal S is set every 1 msec, and the timing for transmitting the synchronization signal S of each base station apparatus is set based on the transmission order notified from the management server or the like. And For example, when the base station apparatus 1d determines that it is the fourth synchronization signal transmission timing, the information on the basic frame start time Tad of the base station apparatus 1d and the start timing Ft of the basic frame transmission period Ft are 60 msec. Information indicating every second and information indicating that the transmission timing of the synchronization signal Sd is 4 msec after the start time Ta of the basic frame transmission period Ft are recorded in the memory.

  When the timing determination unit 16 receives the synchronization signal Sc from the synchronization timing signal generation unit 15, the base station ID of the base station device 1c stored in the synchronization signal Sc and the base set by the base station device 1c by the synchronization process The start time Tac of the frame transmission period Ft is read. Then, the start time Tad of the base frame transmission period Ft stored in the memory in advance is rewritten to the start time Tac of the basic frame Ft stored in the synchronization signal Sc (step S108). As a result, the basic frame start time Tad stored in the own device coincides with the basic frame start time Tac of the base station device 1c determined to have good synchronization accuracy.

 The base station apparatus 1d that has performed the synchronization process stores that the start timing of the basic frame transmission period is every 60 msec seconds, and therefore, based on the start time Tac of the newly set basic frame transmission period Ft, 60 msec. Every second, it is detected that the basic frame transmission period Ft starts. As a result, the transmission time (transmission period St) of the synchronization signal S in the basic frame transmission period Ft and the subsequent transmission time (data period Dt) of the communication data can be transmitted with high accuracy. The synchronization signal Sd and the communication data Dd from the own device are transmitted to the terminal device 2 without colliding with the synchronization signals Sa, Sb, Sc and the like transmitted from 1b and 1c and the communication data Da, Db, Dc and the like. Will be able to.

In the above-described processing, the synchronization processing is performed by matching the start time of the base frame of the base station device 1 with the start time of the base frame of another base station device with the highest accuracy. As another method, the basic frame of the base station device 1 is calculated by averaging the differences between the start times of the basic frames of the other base station devices with the highest accuracy and the start times of the basic frames of other base station devices. You may make it match | combine the start time of.
In addition, a synchronization accuracy index value indicating the time at which the synchronization process is performed is read from the synchronization signal that stores the basic frame start time used to calculate the difference, and a weight value (synchronization value) corresponding to the synchronization accuracy index value is read from the difference. In the accuracy index value, the weight value is increased for the most recent time). Then, the integrated value is calculated for each difference calculated from all the synchronization signals other than the synchronization signal in which the start time of the earliest basic frame is stored, and the average is the basis of the other base station apparatus with the highest accuracy. The value may be added to the start time of the frame, and the value may be overwritten on the start time of the basic frame stored in the memory in advance to establish synchronization.

In the above-described embodiment, the synchronization accuracy index value of the own device is the synchronization time itself in each base station device, but other index values may be used.
FIG. 10 is a conceptual diagram of a first example in which how much past the basic frame subjected to synchronization processing in each base station apparatus is from the current time T1 is used as the synchronization accuracy index value.
In FIG. 10, for example, after performing the synchronization process, the base station apparatus 1b transmits a synchronization signal with a synchronization accuracy index value fb “1” as a synchronization signal index value. Thereafter, unless the synchronization operation is performed, the synchronization accuracy index value fb is transmitted by adding 1 for each basic frame. Since the basic frame transmission time ht is fixed, which base station apparatus is closer to the current time T1 by comparing the synchronization accuracy index values fb, fc, and fd of the base station apparatuses 1b, 1c, and 1d. It is possible to determine whether the synchronization processing has been performed at the timing. In the case of FIG. 10, the synchronization accuracy index values of the base station devices at the current time T1 are fb = 4, fc = 2, and fd = 3, and it is determined that the synchronization accuracy is good in the order of base station devices 1c>1d> 1b. To do.

FIG. 11 is a conceptual diagram of a second example in which how much past the basic frame subjected to the synchronization processing in each base station apparatus is from the current time T1 is used as the synchronization accuracy index value.
In FIG. 11, for example, the base station apparatus 1 b transmits the value of the basic frame transmission time ht as the synchronization signal index value to the synchronization signal after performing the synchronization process. Thereafter, unless a synchronization operation is performed, a time value obtained by multiplying the basic frame transmission time ht by a number obtained by adding 1 to each basic frame is transmitted as a synchronization accuracy index value. Since the basic frame transmission time ht has the same length in the system, which base station apparatus is closer to the current time T1 by comparing the synchronization accuracy index values of the base station apparatuses 1b, 1c, and 1d. It is possible to determine whether the synchronization processing has been performed at the timing. In the case of FIG. 11, the synchronization accuracy index values tb = ht × 4, tc = ht × 2, td = ht × 3 of each base station device at the current time T1, and the synchronization accuracy in the order of base station devices 1c>1d> 1b. Judge that is good.

(Second embodiment)
Next, a second embodiment of the synchronization process of the base station apparatus will be described.
FIG. 12 is a schematic diagram of a communication system including a base station apparatus according to the second embodiment. FIG. 13 is a diagram illustrating a flow of synchronization processing of the base station apparatus according to the second embodiment. In this embodiment, the layer value indicating the layer of the synchronization source given to the base station apparatus that is the transmission source of the synchronization signal is stored in the synchronization signal.
The hierarchy value will be described in more detail. The base station that has performed synchronization processing using the synchronization signal transmitted from the base station apparatus 1a whose reference layer is the layer = 1 (indicating that the synchronization accuracy is the best) and whose layer value is 1 The hierarchy value of the station apparatuses 1b and 1c = 2, and the hierarchy value of the base station apparatuses 1d and 1e that have performed synchronization processing using the synchronization signal transmitted from the base station apparatus 1b of the hierarchy value 2 = 3. Each base station apparatus sets a layer value obtained by adding 1 to the layer value indicating the layer of the synchronization source given to the base station device that is the transmission source of the synchronization signal used for the synchronization process, Keep it in memory.

  Then, in the synchronization process, the base station apparatus sets the layer value to the higher layer (at the start time of the basic frame set by the synchronization process by the base station apparatus 1 that is the transmission source of the synchronization signal stored in the received synchronization signal). Based on the calculation result, the base station apparatus having a smaller layer value is weighted higher and the average of the start times of the weighted basic frames is calculated. Perform synchronization processing.

Hereinafter, the processing according to the second embodiment will be described with reference to FIG. 13 taking the operation of the base station apparatus 1e as an example.
First, the radio reception unit 11 of the base station device 1e receives synchronization signals from all of the base station devices (base station devices 1b and 1d in the case of FIG. 13) located in a range where the synchronization signal can be received among other base station devices. Received (step S201), the synchronization signal detector 14 detects it (step S202). The synchronization signal stores the base station IDs of the transmission source base station devices 1b and 1d, the layer value, and the start time of the basic frame set by the base station device 1 indicated by the base station ID through the synchronization process. ing. The synchronization signal detection unit 14 notifies the synchronization timing signal generation unit 15 of the detected synchronization signal. The control of the synchronization timing signal generator 15 is different from that of the first embodiment, and will be described below using only the functional block diagram of FIG.

  The synchronization timing signal generation unit 15 associates the base station ID stored in the synchronization signal with the layer value and the start time of the basic frame set by the base station device 1 indicated by the base station ID through the synchronization process. Store in memory. Then, it is determined whether or not synchronization signals have been received from all other base station devices 1 (step S203). When synchronization signals have been received from all other base station devices 1, the received synchronization signals are used as a reference. It is determined whether or not a synchronization signal from the base station apparatus 1a, that is, the base station apparatus 1a having the layer value 1 is included (step 204). If the synchronization signal from the base station device 1a is included, the start time of the basic frame stored in the synchronization signal transmitted from the reference base station device having the layer value “1” is acquired (step 205), and the memory Is rewritten at the start time of the basic frame stored in (step 206), and the synchronization processing is terminated. On the other hand, if the synchronization signal received from the base station apparatus 1a is not included in the received synchronization signal, the combination of the hierarchical value of each base station apparatus and the start time of the basic frame included in all the received synchronization signals is acquired. (Step 207). The synchronization timing signal generation unit 15 uses the difference from the start time of the earliest basic frame stored in the synchronization signal as another synchronization signal other than the synchronization signal in which the start time of the earliest basic frame is stored. Calculation is performed according to the stored basic frame start time (step S208). Further, the layer value is read from the synchronization signal storing the basic frame start time used for the calculation of the difference, and the weight value corresponding to the layer value is added to the difference (step S209). Then, the integrated value is calculated for each difference calculated from all the synchronization signals other than the synchronization signal in which the start time of the earliest basic frame is stored, and the average is calculated (step S210). And

Here, it demonstrates using a specific example. From FIG. 12, the base station device 1e receives the synchronization signal transmitted from the base station device 1b, the base station device 1c, and the base station device 1d, and performs the synchronization processing and the processing after step S207 in FIG. . FIG. 14 is a schematic diagram showing the relationship of the basic frame start time of each base station apparatus.
The synchronization signal b transmitted from the base station apparatus 1b has a layer value = 2, the basic frame start time = Hb, and the synchronization signal c transmitted from the base station apparatus 1c has a layer value = 2, the basic frame start time = Hc. The synchronization signal d transmitted from the base station apparatus 1d stores the layer value = 3 and the basic frame start time = Hd. Further, as shown in FIG. 14, it is assumed that the basic frame start time Hb of the base station apparatus 1b is the earliest time among the basic frame start times Hb, Hc, and Hd.

In such a case, in the base station apparatus 1e, the synchronization timing signal generation unit 15 of the base station apparatus 1d has the earliest time of the basic frame start time Hb in the synchronization signal transmitted from the base station apparatus 1b. The difference between the basic frame start times Hc and Hd in the signal is calculated. If the respective differences are the difference Δc and the difference Δd,
Difference Δc = Basic frame start time Hc−Basic frame start time Hb
Difference Δd = Basic frame start time Hd−Basic frame start time Hb
It is. Then, for the difference Δc, the layer value 2 is acquired from the synchronization signal in which the basic frame start time Hc used to calculate the difference is stored, and the weight value ½ is added to obtain the difference Δc × (1 / 2) is calculated. Further, for the difference Δd, the layer value 3 is acquired from the synchronization signal in which the basic frame start time Hd used to calculate the difference is stored, and the weight value 1/3 is added to obtain the difference Δd × (1 / 3) is calculated. In other words, the smaller the hierarchy value, the greater the weighting. Then, the average of these integrated values, {difference Δc × (1/2) + difference Δd × (1/3)} / 2, is calculated, and the value is added to the basic frame start time Hb to calculate the basic frame start time Hx. Is calculated (step 211), and the value is set as a timing correction value. In addition to this, the timing correction value may be calculated by simply adding the average value of the difference Δc and the difference Δd to the basic frame start time Tb without using the weight value. Then, the synchronization timing signal generation unit 15 notifies the timing determination unit 16 of the synchronization timing signal storing the timing correction value.

  The timing determination unit 16 receives the clock signal counted by the clock unit 13. Then, the start timing of the basic frame transmission period as shown in FIG. 4 and the transmission timing of the synchronization signal a within the basic frame transmission period are stored in advance in a memory or the like. For example, it is assumed that the basic frame is repeated in units of 60 msec (milliseconds), and the synchronization period is 5 msec. At this time, in the synchronization period, the timing at which the device transmits the synchronization signal is determined to be the second timing transmission timing (assuming the timing is measured every 1 msec) based on the transmission order notified from the management server or the like. Information indicating that the basic frame start time, the start timing of the basic frame transmission period every 60 msec seconds, and the transmission timing of the synchronization signal a is 2 msec after the start timing of the basic frame transmission period Is recorded in the memory.

  When the timing determination unit 16 receives the synchronization timing signal from the synchronization timing signal generation unit 15, the timing determination unit 16 reads the timing correction value stored in the synchronization timing signal. Then, the start time of the basic frame stored in the memory in advance is rewritten to the basic frame start time Hx indicated by the timing correction value stored in the synchronization timing signal (step S212).

As a result, by repeating the processing of the second embodiment, the basic frame start times set in the base station apparatus in the communication system coincide with each other, so that there is no difference in the basic frame start time synchronization timing. As a result, the transmission time of the synchronization signal and the transmission time of the subsequent communication data in the basic frame transmission period can be transmitted with high accuracy, so that they do not collide with the synchronization signal and communication data transmitted from other base station devices. The terminal device 2 can be transmitted with a synchronization signal and communication data from its own device.
In the second embodiment, the basic frame start time used as a reference for calculating the difference Δ is the thing of the base station device with the earliest time, but in what order the reference basic frame start time is used. Can be changed as appropriate.

  The base station apparatus described above has a computer system inside. Each process described above is stored in a computer-readable recording medium in the form of a program, and the above process is performed by the computer reading and executing the program. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, what is called a difference file (difference program) may be sufficient.

It is a block diagram which shows the structure of a communication system. It is a functional block diagram of a base station apparatus. It is a functional block diagram of a synchronous timing signal generation part. It is a figure which shows the process outline | summary of a synchronous signal transmission process. It is a figure which shows the flow of the synchronous process of the base station apparatus by a 1st Example. It is a figure which shows the process outline | summary of a synchronous signal transmission process. It is a schematic diagram which shows the communication state between base station apparatuses. It is a schematic diagram which shows the communication state between base station apparatuses. It is a schematic diagram which shows the synchronous process time of a base station apparatus. It is a conceptual diagram of the 1st example in case the basic frame which performed the synchronization process in each base station apparatus is how much past from the present time T1 is used as a synchronization accuracy index value. It is a conceptual diagram of the 2nd example in case the basic frame which performed the synchronization process in each base station apparatus uses how much past it is from the present time T1 as a synchronization accuracy index value. It is the schematic of the communication system containing the base station apparatus by 2nd Example. It is a figure which shows the flow of the synchronous process of the base station apparatus by 2nd Example. It is a schematic diagram which shows the relationship of the basic frame start time of each base station apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base station apparatus 2 ... Terminal device 11 ... Radio | wireless receiving part 12 ... Control part 13 ... Clock part 14 ... Synchronization signal detection part 15 ... Synchronization timing signal generation part 16 ... Timing determination unit 17 ... Synchronization signal generation unit 18 ... Wireless transmission unit 151 ... Synchronization accuracy index detection unit 152 ... Synchronization accuracy index comparison unit 153 ... Synchronization accuracy index storage unit 154 ..Synchronous processing instruction section

Claims (8)

In a communication system in which each of a plurality of base station devices synchronizes and transmits information to a wireless terminal connected to the own device,
Base station equipment
A synchronization signal for synchronization between the plurality of base station devices, and the transmission source base station device performs synchronization processing as first synchronization accuracy index information that can specify the accuracy of synchronization time in the transmission source base station device. Synchronization signal receiving means for receiving a synchronization signal storing information relating to the time when
Synchronization accuracy index information storage means for storing information about the time at which the own apparatus performed the synchronization process as second synchronization accuracy index information capable of specifying the accuracy of the synchronization time at which the own apparatus is synchronized ;
A synchronization signal storing the first synchronization accuracy index information when the accuracy of the synchronization time specified by the first synchronization accuracy index information is better than the accuracy of the synchronization time specified by the second synchronization accuracy index information Synchronization means for correcting the timing of transmitting a synchronization signal from the own device based on the reference time stored in
A communication system comprising: The synchronization signal receiving means receives a synchronization signal transmitted from a plurality of other base station devices,
The synchronization means corrects the timing of transmitting the synchronization signal from the own device based on the reference time stored in the synchronization signal storing the first synchronization accuracy index information indicating the most accurate synchronization time. The communication system according to claim 1. In a communication system in which each of a plurality of base station devices synchronizes and transmits information to a wireless terminal connected to the own device,
Base station equipment
A synchronization signal for synchronization in the plurality of base station devices, the synchronization signal containing information about the time of performing the Oite synchronization to the base station apparatus of the transmission source, the other plurality of base stations Synchronization signal receiving means for receiving,
At the time at which the synchronization processing was performed for each difference between the synchronization reference time with the highest accuracy among the synchronization reference times stored in the synchronization signals transmitted from the other plurality of base station devices and the other synchronization reference times Based on the weighted average according to the synchronization means for correcting the timing of transmitting the synchronization signal from the own device,
A communication system comprising: The layer value obtained by adding 1 to the layer value indicating the layer of the synchronization source given to the base station device that is the transmission source of the synchronization signal is stored in the received synchronization signal,
The synchronization means weights the difference based on a layer value in the synchronization signal used for calculation of the difference, and increases the weight of the layer value as the layer is higher. The communication system according to claim 1, wherein the timing for transmitting the synchronization signal from the own apparatus is corrected based on the communication system. A synchronization method of a communication system in which each of a plurality of base station devices synchronizes and transmits information to a wireless terminal connected to the device,
The synchronization signal receiving means of the base station apparatus is a synchronization signal for synchronizing with the plurality of base station apparatuses, and the first synchronization accuracy index information that can specify the accuracy of the synchronization time in the base station apparatus of the transmission source As the receiving base station apparatus receives a synchronization signal storing information on the time when the synchronization processing was performed ,
The synchronization accuracy index information storage means of the base station device stores information on the time at which the device has performed synchronization processing as second synchronization accuracy index information that can specify the accuracy of the synchronization time at which the device has synchronized ,
The synchronization means of the base station apparatus, when the accuracy of the synchronization time specified by the first synchronization accuracy index information is better than the accuracy of the synchronization time specified by the second synchronization accuracy index information, A synchronization method, comprising: correcting a timing of transmitting a synchronization signal from the own apparatus based on a reference time stored in a synchronization signal storing synchronization accuracy index information. A synchronization method of a communication system in which each of a plurality of base station devices synchronizes and transmits information to a wireless terminal connected to the device,
Synchronizing signal receiving means of the base station apparatus, a synchronization signal for synchronization in the plurality of base stations, storing information about the time of performing the Oite synchronization to the base station apparatus of the transmission source A synchronization signal is received from a plurality of other base station devices,
The synchronization means of the base station apparatus includes each difference between the most accurate synchronization reference time and the other synchronization reference time among the synchronization reference times stored in the synchronization signal transmitted from the other plurality of base station apparatuses. A synchronization method characterized by correcting the timing of transmitting a synchronization signal from the own apparatus based on a weighted average according to the time at which the synchronization processing is performed . A base station apparatus of a communication system that transmits information to a wireless terminal connected to the base station apparatus in synchronization with each of a plurality of base station apparatuses,
A synchronization signal for synchronization between the plurality of base station devices, and the transmission source base station device performs synchronization processing as first synchronization accuracy index information that can specify the accuracy of synchronization time in the transmission source base station device. Synchronization signal receiving means for receiving a synchronization signal storing information relating to the time when
Synchronization accuracy index information storage means for storing information about the time at which the own apparatus performed the synchronization process as second synchronization accuracy index information capable of specifying the accuracy of the synchronization time at which the own apparatus is synchronized ;
A synchronization signal storing the first synchronization accuracy index information when the accuracy of the synchronization time specified by the first synchronization accuracy index information is better than the accuracy of the synchronization time specified by the second synchronization accuracy index information Synchronization means for correcting the timing of transmitting a synchronization signal from the own device based on the reference time stored in
A base station apparatus comprising: A base station apparatus of a communication system that transmits information to a wireless terminal connected to the base station apparatus in synchronization with each of a plurality of base station apparatuses,
A synchronization signal for synchronization in the plurality of base station devices, the synchronization signal containing information about the time of performing the Oite synchronization to the base station apparatus of the transmission source, the other plurality of base stations Synchronization signal receiving means for receiving,
At the time at which the synchronization processing was performed for each difference between the synchronization reference time with the highest accuracy among the synchronization reference times stored in the synchronization signals transmitted from the other plurality of base station devices and the other synchronization reference times Based on the weighted average according to the synchronization means for correcting the timing of transmitting the synchronization signal from the own device,
A base station apparatus comprising:

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