JP7123642B2 - Wireless communication method, wireless communication system and wireless communication device - Google Patents

Description

The present invention relates to a radio communication method in a radio communication system used for mobile control.

In recent years, there is a movement to utilize wireless communication for control of mobile bodies. For example, in the field of train control, Level 2 and later of ETCS (European Train Control System) and CBTC (Communication Based Train Control) are known. Also, in the field of automatic driving of automobiles, V2X (Vehicle to Everything) and the like are known. Communication used for mobile control requires reduction of packet error rate, latency, delay jitter, and the like.

Further, as disclosed in Non-Patent Document 1, ATACS (Advanced Train Administration and Communication System), which is a wireless train control system, has been proposed. In the ATACS, two-way communication is performed between a mobile radio station on the train and a fixed radio station on the ground, and train control is performed by exchanging train position information and train entry permission points.

There is also a technique for improving the reliability of communication by frequency hopping. For example, in Patent Document 1, an antenna, a transmitting/receiving unit connected to the antenna, and a transmitting/receiving unit are controlled, the same transmission data is input to the transmitting/receiving unit at the same time, and the frequency is sent to the transmitting/receiving unit at each switching cycle of frequency hopping. a radio control unit for instructing the start of channel availability confirmation processing, wherein the transmitting/receiving unit switches the frequency channel at regular time intervals in synchronization with the other party of communication, and at the same time, each transmitting/receiving unit uses a different frequency. and a hopping control unit for controlling the use of the frequency channel, and when it is determined that the frequency channel is idle during the period from the start of the idle state confirmation process to the elapse of a predetermined time, the frequency channel is used. A wireless communication device is described that transmits the transmission data to a communication partner.

WO2014/045402

Hideo Nakamura, "Innovation of Railway Signaling System", Information Processing Society of Japan, Vol. 55, No. 3, pp268-276, March 2014

In the radio communication system described in Patent Document 1, timing synchronization is established between fixed radio stations and mobile radio stations, and frequency hopping is applied to improve communication reliability. and the mobile radio station are not disclosed. As a specific example of the synchronization method, a method using a preamble signal, which is also used in wireless LANs, is known. There is a possibility that the data signal may not be correctly transmitted due to erroneous synchronization with the preamble signal of a fixed radio station different from the fixed radio station performing the transmission.

The present invention is a wireless communication system that bidirectionally transmits mobile control information using time-division channels that perform frequency hopping between a fixed wireless station and a mobile wireless station. The purpose is to provide a communication method.

A representative example of the invention disclosed in the present application is as follows. That is, a radio communication method in a radio communication system in which mobile unit control information is bidirectionally transmitted between a fixed radio station and a mobile radio station using a frequency-hopping time-division channel, wherein the identifier of the fixed radio station is It consists of a group identifier for uniquely identifying a group and an intra-group identifier for uniquely identifying a fixed radio station within the group. are synchronized with each other, and the plurality of fixed radio stations forming the group use a preamble signal obtained by orthogonalizing the frequency hopping sequence determined based on the intra-group identifier, and the fixed radio stations of the different groups Between stations, overlap of frequency hopping sequences is allowed in some or all of the time division channels, different preamble signals are used , and the fixed radio station and mobile radio stations connected to the fixed radio station time-multiplexing a preamble signal selected based on the identifier of the fixed wireless station and the mobile control information using a time division channel determined according to a frequency hopping sequence selected based on the identifier of the wireless station; wherein the preamble signal is a combination of a signal of a first preamble sequence and a signal of a second preamble sequence, and the first preamble sequence is transmitted by all the fixed radios in the radio communication system Station and said mobile radio station, said second preamble sequence being selected on the basis of the identity of said fixed radio station .

According to one aspect of the present invention, erroneous synchronization due to erroneous detection of the preamble of another fixed radio station can be reduced. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is a diagram showing a configuration example of a wireless communication system according to an embodiment of the present invention; FIG. 4 shows an example of a frequency hopping matrix and a preamble signal according to the embodiment; FIG. 4 is a diagram showing a configuration example of a time-division channel according to the embodiment; It is a figure which shows the example of a frame structure of a present Example. FIG. 10 is a diagram showing an example of information elements transmitted by a broadcast time-division channel according to the present embodiment; FIG. 4 is a diagram showing an example of information elements transmitted on the initial access time-division channel of the present embodiment; FIG. 4 is a diagram showing an example of information elements of a data signal time-division channel according to the present embodiment; It is a figure which shows the structural example of the fixed radio station of a present Example. 1 is a diagram showing a configuration example of a mobile radio station of this embodiment; FIG. FIG. 2 is a diagram showing an example of device configurations of a fixed radio station and a mobile radio station according to the present embodiment; FIG. 10 is a diagram showing an example of time-division channels when two types of preamble sequences of this embodiment are applied;

<Example 1>
FIG. 1 is a diagram showing a configuration example of a wireless communication system according to an embodiment of the present invention.

The radio communication system of this embodiment comprises a plurality of fixed radio stations 13 and one or a plurality of mobile radio stations 23 .

The center-side mobile body control device 11 receives observation information around the mobile body 21 , determines a control target for the mobile body 21 based on the input observation information, and transmits the control target to the mobile radio station 23 .

Although the method of determining the control target from the observation information is out of the scope of the present invention, for example, the operation related to ATACS (Advanced Train Administration and Communication System) described in Non-Patent Document 1 can be applied. Note that mobile control information in this specification is information about this observation information and control targets.

The edge-side mobile body control device 22 performs two-way transmission of mobile body control information with the center-side mobile body control device 11 . Observation information around the moving body 21 is transmitted to the center side moving body control device 11, a control target is input from the center side moving body control device 11, and the movement of the moving body 21 is autonomously controlled according to the input control target and observation information. control effectively.

The fixed radio station 13 has at least one antenna 14, receives observation information converted into radio signals, converts control targets into radio signals, and transmits the radio signals.

The mobile radio station 23 is mounted on the mobile object 21, has at least one antenna 24, receives control targets converted into radio signals, converts observation information into radio signals, and transmits the signals.

A center-side mobile unit control device 11 is connected to a plurality of fixed radio stations 13 via a backbone network 12 . Here, when the radio communication system of this embodiment is applied to radio train control, for example, the moving object 21 is a train, and the fixed radio station 13 is a radio base station provided along the route along which the train travels. Yes, the mobile radio station 23 may be regarded as an on-board radio station attached to the train. In addition, the center-side moving body control device 11 is a part of a ground-side control system that generates train control information, and for example, generates stop limit point information as one piece of train control information or performs higher-level calculations. It may be regarded as a device that has a function of acquiring from the device and transmitting it to the fixed radio station 13, or a device that receives position information transmitted from the on-board control system (to be described later) via the fixed radio station 13. FIG.

Further, when the wireless communication system of this embodiment is applied to wireless train control, the edge-side mobile body control device 22 may be regarded as a part of the on-board control system, for example. The edge-side mobile body control device 22 is connected to, for example, communication means with a ground unit or distance measurement means using radio, and transmits the position information acquired by these means to the fixed radio station 13 via the mobile radio station 23. It may be regarded as a device that transmits information to the control system on the side of the vehicle and passes the stop limit point information received from the control system on the ground side to the host control device on the side of the vehicle. The configuration of the on-board control system can be arbitrarily determined, and for example, the edge-side mobile body control device 22 and the mobile radio station 23 may be configured as an integrated device. Also, a system configured by such a vehicle-side control system and the above-described ground-side control system may be regarded as a train control system.

FIG. 2 shows an example of a frequency hopping matrix and a preamble signal according to this embodiment.

FIG. 2A shows an example of a frequency hopping matrix.

The vertical axis of the frequency hopping matrix represents frequency subchannels obtained by dividing the frequency band available for the system, and is divided into 16 frequency subchannels in this embodiment. A number (FDC No.) is assigned to each frequency subchannel. The horizontal axis represents time-division channels, and each time-division channel is assigned a number (TDC No.). In this embodiment, the same pattern is repeated with a period of 16 time-division channels.

A number from 0 to 15 is drawn in each square of the frequency hopping matrix. This number represents the lower 4 bits of the fixed radio station (FRS) identifier. For example, if we focus on the assignment of 0 in the colored lower 4 bits, frequency subchannel #0 is assigned to the top time division channel, and the frequency subchannel number is incremented by 3 each time the time division channel is advanced by one. If the result is 16 or more, the frequency subchannel number is subtracted by 16. When the serial number of the time division channel reaches 16, it wraps around to 0.

Such a series of frequency subchannel numbers for each time-division channel for each fixed radio station is a frequency hopping sequence. In the example shown in FIG. 2, the period of the frequency hopping sequence is 16 because it folds to the left every 16 time division channels.

Under the constraint that each fixed radio station 13 always uses one frequency subchannel in each time division channel, mutually orthogonal frequency hopping sequences can be generated by the number of frequency subchannels.

If this constraint is satisfied, the effect of the present invention can be obtained for any frequency hopping sequence. However, in order to obtain the effect of the present invention, it is necessary that the fixed radio station 13 and the mobile radio station 23 can reproduce the same frequency hopping sequence using the lower bits of the fixed radio station ID as an index.

One of the methods is to hold a table that can acquire the frequency hopping sequence for each cycle by inputting the lower bits of the fixed radio station ID in each of the fixed radio station 13 and the mobile radio station 23 . This table is written in the fixed radio station 13 and the mobile radio station 23 at the time of shipment, and initial values are set when each radio station is activated.

Another method is to formulate the method of generating the frequency hopping sequence, and input the serial number of the time-division channel and the lower bits of the identifier of the fixed radio station 13 into the formula as explanatory variables. It is a method of calculating the number. The frequency hopping sequence shown in FIG. 2 can be generated by Equation 1 below.

However, TDC is the serial number of the time division channel, frsid _lsb is the lower bits of the fixed radio station identifier (4 bits in FIG. 2), N _TDC is the period of the frequency hopping sequence, and the length of the horizontal axis of the matrix is (16 in FIG. 2), step is the number added to the frequency subchannel number each time the time division channel advances by one (3 in FIG. 2), and N _FDC is the total number of frequency subchannels (16 in FIG. 2). ), FDC _ini is the frequency subchannel initial value of the frequency hopping sequence and is defined for each frsid _lsb (FDC _ini (frsid _lsb )=frsid _lsb in FIG. 2), and modulo is an operation for obtaining the remainder of division. be.

The above formula is a formula for generating a frequency hopping sequence in which the frequency subchannel numbers FDC(TDC, frsid _lsb ) for each time division channel serial number TDC are arranged for the lower bits frsid _lsb of the fixed radio station identifier. It may be in the form of a recurrence formula with FDCini(frsid _lsb ) as the initial value.

By the above procedure, the frequency hopping sequence for the lower bits of the fixed radio station identifier can be generated. Fixed radio stations 13 having different lower bit values of fixed radio station identifiers do not use the same frequency subchannel in the same time division channel, that is, the orthogonality of frequency hopping sequences is maintained in all time division channels. In order to obtain the effects of the present invention, it is desirable to arrange the fixed radio stations 13 having the same low-order bit of the fixed radio station identifier as far apart as possible.

FIG. 2B shows an example of a preamble signal with low cross-correlation.

A preamble signal is a signal having a certain fixed time length (M samples), and different preamble signals are generated using the high-order bit (the high-order 1 bit in the case of FIG. 2) of the fixed radio station identifier as an index.

In the example shown in FIG. 2, sine waves with different frequencies are used as preambles. The sine wave of the fundamental frequency is a preamble transmitted by the fixed radio station 13 with the higher bit of the fixed radio station identifier=0 and the mobile radio station 23 communicating with this fixed radio station, and is a sine wave whose phase rotates by 2π every M samples. is. On the other hand, the double-frequency sine wave is a preamble transmitted by the fixed radio station 13 with the higher bit of the fixed radio station identifier=1 and the mobile radio station 23 communicating with this fixed radio station 13, and has M samples and a phase of 4π. A rotating sine wave.

In the range of 2π cycles of the fundamental frequency, the product of signals with different double frequencies is integrated to 0, and the product of signals with the same frequency is integrated to 1. This is a property of the Fourier transform. In other words, if sine waves with different frequencies are used as preambles, it is theoretically possible to prepare a plurality of preambles with zero cross-correlation.

A preamble sequence using a sine wave indexed by the high-order bits frsid _msb of the fixed radio station identifier is represented by Equation 2 below. t is a time sample counter that takes values from 0 to M-1.

In this embodiment, it is desirable that the preamble sequences are orthogonal to each other, but considering the same preamble sample length, the number of preamble sequences is smaller than that of preamble sequences that are quasi-orthogonal to each other.

What kind of preamble sequence to select depends on the system, but in the case of a system that requires many preamble sequences (for example, the number of fixed radio stations 13 is large), a quasi-orthogonal preamble sequence such as a Gold sequence It may be more appropriate to use

As explained above, based on the fixed radio station identifier, a preamble sequence can be generated from the upper bits and a frequency hopping sequence can be generated from the lower bits. When a group is composed of fixed radio stations 13 having the same high-order bits of identifiers, the same preamble signal is used by orthogonalizing frequency hopping sequences within the group, and fixed radio stations 13 having different high-order bits of identifiers belong to different groups. Become. On the other hand, when a group is formed of fixed radio stations 13 with the same identifier lower bits, the same frequency hopping sequence is used by orthogonalizing or quasi-orthogonal preamble signals within the group, and fixed radio stations with different identifier lower bits are used. Station 13 is in another group.

In this specification, the index specifying the preamble sequence and the index specifying the frequency hopping sequence are derived from the fixed radio station identifier, but both indices are treated as parameters with different names from the fixed radio station identifier. , that combination of parameters may be considered equivalent to the fixed radio station identifier herein. Also, the combination of parameters for calculating Equation 1 and Equation 2 can be considered equivalent to the fixed radio station identifier of this specification. In other words, combinations of parameters that differ between fixed radio stations can be regarded as deformations of fixed radio station identifiers.

FIG. 3 is a diagram showing a configuration example of a time-division channel according to this embodiment.

As shown in FIG. 2A, a fixed radio station 13 whose fixed radio station identifier has lower four bits of 0, and a mobile radio station 23 that communicates with the fixed radio station 13 have colored time-division channels and frequencies. Transmits radio signals on subchannels.

However, since it is either the fixed radio station 13 or the mobile radio station 23 in the fixed radio station group that can transmit radio signals on the colored subchannels, the communication direction is defined in advance for each time-division channel, or It is necessary to dynamically control the direction of communication between the fixed radio station 13 and the mobile radio station 23 .

Regardless of whether the fixed radio station 13 or the mobile radio station 23 transmits a radio signal in each time division channel, the configuration within the time division channel is of the same format. In other words, the time-division channel consists of a preamble sequence, a data signal that is a radio signal containing information related to mobile control, and a guard time (radio signals are not transmitted) to absorb time lags between stations that occur due to various factors. ) are time-multiplexed. The length of the preamble sequence is always fixed, but the ratio of data signal and guard time may be dynamically changed as needed.

As the preamble sequence, the sequence selected based on the fixed radio station identifier is arranged as it is. The data signal is generated as a time domain signal by, for example, OFDM (Orthogonal Frequency Domain Multiplex) secondary modulation. The modulation symbol for each subcarrier is based on the bit sequence after signal processing generated by signal processing such as adding CRC (Cyclic Redundancy Code), convolutional coding, interleaving, and repetition to the bit sequence of mobile control information. are generated by a primary modulation method such as QPSK (Quadrature Phase Shift Keying).

Although the effect of the present invention does not change even if the data signal is converted into a radio signal using an arbitrary modulation method, a protocol may be defined in advance between the fixed radio station 13 and the mobile radio station 23, or the transmission side may It is necessary to unify the method among wireless stations by a method such as separately transmitting the applied primary modulation method, coding rate, and information bit sequence length at the beginning of the data signal.

FIG. 4 is a diagram showing a frame configuration example of this embodiment.

The frame configuration example shown in FIG. 4 shows the use of each frame number, intra-frame time division channel number, and intra-frame time division channel number corresponding to the time division channel shown in FIG.

In the example shown in FIG. 4, a frame consists of 10 intra-frame time division channels. In this embodiment, it is not assumed that the period of the frequency hopping sequence and the frame length match, and they do not have to match.

The number of time division channels in a frame may vary according to system needs. Alternatively, the frequency subchannel may be selected by returning to the beginning of the frequency hopping sequence at each frame beginning. Furthermore, FDC _ini (frsid _lsb ) may be changed in conjunction with the frame number. Even with such a change, the orthogonality of the frequency hopping sequences between the fixed radio stations 13 in the group is maintained, so the effect of the present invention can be obtained.

The relationship between the serial number _TDC of the time division channel shown in FIG.

N _TDClocal is the number of time division channel numbers in the frame (10 in FIG. 4). Frame numbers wrap within a finite range as needed. For example, when the frame number reaches 256, processing to wrap back to 0 is performed. Along with this, serial numbers of time-division channels are also folded back within a limited range.

If the frame number and the number of time-division channels within the frame are known, the fixed radio station 13 and the mobile radio station 23 can know serial numbers of time-division channels for all time-division channels within the frame, and frequency hopping for the fixed radio station 13 can be performed. By referring to the sequence, the number of frequency subchannels available in each time division channel is known.

In principle, the same rule applies to all frames for use of each time-division channel within a frame. When the application rule is to be changed during operation, the fixed radio station 13 is operated from a device outside the system such as a maintenance terminal to change the application, and the mobile radio station 23 is notified by the time-division channel for notification. Since this is only a principle, the use of each time-division channel does not have to be completely the same among the fixed radio stations 13 as long as it is necessary for the system. However, in order to establish a synchronization process, which will be described later, the use of the time-division channel designated for notification in the initial state is not changed.

Symbols used for each intra-frame time-division channel will be explained. B is a broadcast time division channel, A is an initial access time division channel, and C is a data signal communication time division channel. DL indicates the downlink direction of transmission from the fixed radio station 13 to the mobile radio station 23, and UL indicates the uplink direction of transmission from the mobile radio station 23 to the fixed radio station 13. FIG.

FIG. 5 is a diagram showing an example of information elements to be transmitted on the broadcast time-division channel of this embodiment.

The broadcast time-division channel contains an identifier (FRS ID) of the source fixed radio station 13, a frame number (Frame No.), and information for generating a frequency hopping sequence from a calculation formula. It consists of the number of frequency subchannels to be shifted (step) and the frequency subchannel number (FDCini) when the frame number is 0 and the intra-frame time division channel number is 0.

step and FDC-- ini are transmitted in the format shown in the figure through the broadcast time-division channel. If the information representing the frequency hopping matrix is shared by the fixed radio station 13 and the mobile radio station 23 (eg, written to the fixed radio station 13 and the mobile radio station 23 as initial settings at start-up), step and FDC ini are It does not have to be transmitted on the broadcast time-division channel.

As described in the explanation of FIG. 4, when the usage information of the intra-frame time division channel is dynamically changed, the usage information is added to the information element of the broadcast time division channel shown in FIG. The fixed radio station 13 broadcasts the latest information of

Information elements transmitted on the broadcast time-division channel are radio-signalized by the fixed radio station 13, then multiplexed with a preamble sequence corresponding to the identifier of the fixed radio station 13 and a guard time, and sent to the fixed radio station 13. sent from.

FIG. 6 is a diagram showing an example of information elements transmitted on the initial access time division channel of this embodiment.

The initial access time division channel consists of an identifier (MRS ID) that uniquely identifies the mobile radio station 23 within the system and an identifier (FRS ID) of the fixed radio station 13 to which the initial access time division channel is transmitted. be done.

Information elements to be transmitted on the initial access time-division channel are radio-signalized by the mobile radio station 23, then multiplexed with a preamble sequence based on the identifier of the fixed radio station 13 indicated by the FRS ID and a guard time, and transmitted by the mobile radio. Transmit from station 23 .

The mobile radio station 23 selects the fixed radio station 13 as the transmission destination of the initial access time division channel by comparing the reception power of the preamble sequences transmitted from the fixed radio stations 13 among the fixed radio stations 13 . , to select the fixed radio station 13 with the highest received power.

The preamble sequence may be transmitted when there is no data signal to be transmitted in the time division channel, but in the present invention, it is desirable not to transmit more than necessary from the viewpoint of avoiding erroneous detection of the preamble. On the other hand, since the broadcast time division channel is always transmitted in every frame, the mobile radio station 23 should select the fixed radio station 13 using the preamble sequence in the broadcast time division channel.

Frame synchronization by the mobile radio station 23 will be described later, but a method of selecting the fixed radio station 13 after frame synchronization is established will be described. Further, it is assumed here that synchronization between the fixed radio stations 13 is also established.

Since the mobile radio station 23 has been frame-synchronized, it knows the timing at which the preamble sequence of the broadcast time-division channel is received. Temporarily records received waveforms. The mobile radio station 23 calculates the cross-correlation between the recorded received waveform and the preambles of all fixed radio station groups assumed in the system, and selects the fixed radio station group with the largest cross-correlation. After selecting the fixed radio station group, the frequency subchannel with the largest cross-correlation value of the received waveform is selected. Once the fixed radio station group and the frequency subchannel with the largest cross-correlation value are determined, the fixed radio station identifier can be determined from the content of the broadcast time division channel.

The fixed radio station selection method described here is an example. The mobile radio station 23 identifies a fixed radio station group identifier assumed to be used in the system and an intra-group identifier or a fixed radio station identifier based on the received cross-correlation value of the preamble sequence of the broadcast time-division channel. Any method can be used as long as it can be determined.

FIG. 7 is a diagram showing an example of information elements of the data signal time-division channel of this embodiment.

FIG. 7(A) shows information elements transmitted between the mobile radio station 23 and the fixed radio station 13, to which time-division channels for data signals have already been allocated. The information element consists of at least the identifier of the fixed radio station 13 (FRS ID), the identifier of the mobile radio station 23 (MRS ID), and the information bit sequence (Data Body) which is the body of the data signal. be. The information bit sequence contains information related to mobile control. If the information bit sequence length is variable, the length of the information bit sequence is also added.

FIG. 7(B) shows information elements of a response transmitted from the fixed radio station 13 to the mobile radio station 23 that transmitted the information elements of FIG. 6 on the initial access time-division channel. The information element shown in FIG. 7B has the same basic format as that of FIG. time-division channel number within the frame.

If the time division channel assignment to the mobile radio station 23 fails, no response is returned to the mobile radio station 23 . An example of failure in time-division channel allocation is when the intra-frame time-division channel that can be allocated to the mobile radio station 23 is allocated to another mobile radio station 23 and does not remain. For this reason, the fixed radio station 13 continues to fail in communication for a certain period of time, that is, an error in the information bit sequence continues. , it is desirable to release the allocated intra-frame time division channels.

When the time division channel allocation to the mobile radio station 23 is successful, the information elements shown in FIG. 7B are transmitted to the mobile radio station 23 by the allocated downlink data signal time division channel. Since the mobile radio station 23 does not know which time-division channel is assigned at this point, it decodes all the downlink data signal time-division channels and obtains information elements containing its own mobile radio station identifier. By confirming, information on time division channel allocation can be acquired.

FIG. 8 is a diagram showing a configuration example of the fixed radio station 13 of this embodiment.

Network interface unit 101 realizes two-way communication between center-side mobile unit control device 11 and fixed radio station 13 via backbone network 12 . For two-way communication, for example, IP packets can be used, but if an interface is defined between the fixed radio station 13 and each of the above devices, a system-specific communication protocol may be used.

Downlink transmission buffer 102 temporarily stores downlink mobile control information for each mobile radio station that performs radio communication with fixed radio station 13 . The downlink transmission buffer 102 has a timing adjustment function that makes the mobile control information wait until the timing of transmitting the mobile control information to the radio when transmitting the mobile control information from the center side mobile control device 11 to the mobile radio station 23. Temporary storage of information for retransmitting the same mobile control information wirelessly when the frequency of input of mobile control information from the center-side mobile control device 11 is lower than the transmission frequency (each frame) of have a function.

The time-division channel control section 103 performs control operations on a frame-by-frame basis. The time-division channel control unit 103 instructs the radio digital signal transmission processing unit 104 and the radio digital signal reception processing unit 107 to refer to the usage information of the time-division channels within the frame in FIG. A function of controlling transmission and reception, a function of specifying a frequency subchannel number to be used in each time division channel according to a frequency hopping sequence, a function of specifying a preamble sequence to be used based on a fixed radio station identifier, A function to update the frame number when the processing is completed, manage information elements of the broadcast time-division channel including the frame number and the fixed radio station identifier, and set the latest value to the wireless digital signal transmission processing unit 104 for each frame. and a function of collecting information elements (FIG. 7) to be transmitted in each data signal time-division channel for each time-division channel and setting them in the wireless digital signal transmission processing unit 104 . Also, an information bit sequence is generated by combining information elements transmitted in each time division channel.

Radio digital signal transmission processing section 104 refers to the bit sequence and frequency subchannel number of each time division channel input from time division channel control section 103, and generates a digital radio signal. Signal processing includes adding a CRC (Check Redundancy Code) to the input bit sequence for error detection, convolutional coding for error correction, and interleaving to improve error correction capability and noise-to-noise energy per bit. and repetition, modulation for converting bit strings into amplitude and phase information, time multiplexing of modulated signals and designated preamble sequences, and frequency conversion for transmission on designated frequency subchannels. The wireless digital signal transmission processing unit 104 outputs a baseband digital signal.

The wireless analog signal transmission/reception processing unit 105 performs digital-analog conversion, conversion from the baseband to a high frequency signal, and amplification processing of the output of the high frequency signal on the baseband digital signal input from the wireless digital signal transmission processing unit 104 . A switch for switching transmission and reception is provided in front of the antenna 14. - 特許庁

The radio analog signal received by the antenna 14 is sent to the reception signal processing side by the switch described above, and the weak input signal is amplified, converted from a high frequency signal to a baseband signal, and analog-to-digital converted. It outputs to the digital signal reception processing unit 107 .

The radio digital signal reception processing unit 107 performs frequency shift to shift the signal of the frequency subchannel designated for each time-division channel to the center frequency, and then performs low-pass filter processing on the input digital received signal. after that, estimating the radio channel response, compensating the amplitude phase of the received signal affected by the radio channel using the estimated channel response, and obtaining the information carried on the amplitude phase of the compensated received signal Demodulation processing is performed to restore the bit string, and the bits repeated on the transmission side are combined by deinterleaving and repetition, which perform reverse processing of interleaving on the transmission side for the bit string after demodulation processing.

After combining the received signals at the bit level, error correction decoding such as Viterbi decoding is performed, and the presence or absence of bit errors is determined by checking the CRC assigned to this output. The radio digital signal reception processing unit 107 outputs at least the estimated transmission bit sequence excluding the CRC and the CRC check result indicating the presence or absence of errors.

Initial access processing section 108 acquires a bit sequence without bit errors for the initial access time-division channel from radio digital signal reception processing section 107, refers to time-division channel assignment information in fixed radio station management information 106, and performs initial It is determined whether or not a data signal time division channel can be assigned to the mobile radio station 23 that transmitted the access time division channel. If allocation is possible, the allocation of the mobile radio station 23 is added to the time division channel allocation information of the fixed radio station management information 106, and the time division channel control section 103 performs the initial access time shown in FIG. Output the information element of the response to the split channel.

Uplink transmission buffer 109 is a buffer that temporarily stores uplink mobile unit control information and makes data wait until the timing at which data can be transmitted to backbone network 12 . The uplink transmission buffer 109 stores only data that has been determined to have no bit error as a result of the CRC check, out of the data received on the uplink data signal time-division channel.

FIG. 9 is a diagram showing a configuration example of the mobile radio station 23 of this embodiment.

The network interface unit 201 realizes two-way communication between the mobile radio station 23 and the edge-side mobile body control device 22 . As with the configuration example of the fixed radio station 13 (FIG. 8), this two-way communication may use an IP packet or a system-specific communication protocol.

The upstream transmission buffer 202 is a buffer that temporarily stores upstream mobile control information. The uplink transmission buffer 202 has a function of making the information sequence wait until the radio transmission time of the allocated uplink data signal time-division channel, has a function of temporarily storing information for retransmitting the same mobile unit control information by radio when the frequency of input is low.

Buffer reading processing section 203 reads the latest mobile unit control information for each frame from upstream transmission buffer 202 and writes it to radio digital signal transmission processing section 204 as a bit sequence.

The wireless digital signal transmission processing unit 204 converts the bit sequence related to the data signal input from the buffer reading processing unit 203 and the information elements of the initial access time-division channel input from the initial access processing unit 208 into bit sequences to detect errors. Addition of CRC (Check Redundancy Code) for detection, convolutional coding for error correction, interleaving and repetition to improve error correction capability and anti-noise energy per bit, conversion of bit string to amplitude and phase information modulation, time multiplexing of the modulated signal and the designated preamble sequence, and frequency conversion for transmission on the designated frequency subchannel. The wireless digital signal transmission processing unit 204 outputs a baseband digital signal.

Radio digital signal transmission processing section 204 acquires from time-division channel control section 207 information on fixed radio station identifiers and information on frequency subchannels for determining preamble sequences.

The radio analog signal transmission/reception processor 205 has the same function as the radio analog signal transmission/reception processor 105 of the fixed radio station 13 .

The radio digital signal reception processing unit 209 performs frequency shift to shift the signal of the frequency subchannel designated for each time-division channel to the center frequency, and then performs low-pass filter processing on the input digital received signal. after that, estimating the radio channel response, compensating the amplitude phase of the received signal affected by the radio channel using the estimated channel response, and obtaining the information carried on the amplitude phase of the compensated received signal Demodulation processing is performed to restore the bit string, and the bits repeated on the transmission side are combined by deinterleaving and repetition, which perform reverse processing of interleaving on the transmission side for the bit string after demodulation processing.

After combining the received signals at the bit level, error correction decoding such as the Viterbi decoding method is performed, and the presence or absence of bit errors is determined by checking the CRC assigned to the output. The radio digital signal reception processing unit 209 outputs at least the estimated transmission bit sequence excluding the CRC and the CRC check result indicating the presence or absence of errors.

The radio digital signal reception processing unit 209 performs timing synchronization with respect to the radio signal received from the fixed radio station 13 in addition to decoding processing for these data signals. A sliding correlation operation is performed between the preamble sequence designated by the time-division channel control section 207 and the received signal to estimate the reception timing. to extract

Also, the radio digital signal reception processing unit 209 adjusts the time division channel and frame timing based on the radio signal reception timing transmitted by the connected fixed radio station 13 . That is, when the reception timing of the signal from the fixed radio station 13 is earlier than the time division channel timing of the mobile radio station 23, the time division channel timing of the mobile radio station 23 is advanced. and vice versa to adjust the time division channel timing.

The initial access processing unit 208 performs communication with any fixed radio station 13 as shown in the explanation of FIG. to start.

Initial access processing section 208 first searches for fixed radio station 13 and identifies fixed radio station 13 that is the transmission source of the preamble sequence with the highest received power. Initial access processing section 208 acquires information related to the frame number, fixed radio station identifier, and frequency hopping sequence contained in the broadcast time-division channel transmitted by fixed radio station 13, and stores them in time-division channel management information memory 206. Write. After that, the information shown in FIG. 6 is converted into a bit sequence and written to the wireless digital signal transmission processing unit 204, and under the control of the time division channel control unit 207, the wireless signal of the time division channel for initial access is transmitted as a wireless signal.

When the transmission of the radio signal of the time division channel for initial access is completed, the initial access processing section 208 refers to the use information of the intra-frame time division channel recorded in the time division channel management information memory 206 at the time of initialization. from the wireless digital signal reception processing unit 209 . It is also possible to refer to the intra-frame time-division channel usage information written in the time-division channel management information memory 206, which is included in the broadcast time-division channel.

When initial access processing section 208 acquires information containing the identifier of mobile radio station 23 , initial access processing section 208 writes allocation information contained in the bit sequence into time division channel management information memory 206 . If the information including the identifier of the mobile radio station 23 cannot be acquired, the radio signal transmission of the initial access time division channel is repeated, or the fixed radio station 13 is searched again.

When initial access processing section 208 searches for a fixed wireless station, if it detects a deviation from the frame number generated by time division channel control section 207 before synchronization or the timing of the time division channel, The time division channel control section 207 is notified of the detected deviation. The time division channel control section 207 corrects the timing based on the detected deviation. Also, the initial access processing unit 208 corrects the internal counter of the time division channel control unit 207 regarding the frame number. For the wireless digital signal transmission processing unit 204 and the wireless analog signal transmission/reception processing unit 205, a time-division channel determined by free running is used so that the timing of the wireless time-division channel and frame boundary matches that of the fixed wireless station 13. is corrected by an instruction from the time-division channel control section 207 .

The time-division channel control section 207 performs control operations on a frame-by-frame basis. The radio digital signal transmission processing unit 204 and radio A function of controlling transmission/reception of time-division channels within a frame by the digital signal reception processing unit 209, a function of designating frequency sub-channel numbers used in each time-division channel based on a frequency hopping sequence, and a time-division channel management information memory 206. It has a function of using a preamble sequence transmitted from a stored fixed radio station identifier and a function of updating the frame number when processing for one frame is completed.

The time-division channel control unit 207 always counts frames. is instructed to the wireless digital signal transmission processing unit 204 and the wireless digital signal reception processing unit 209 to correct the . Specifically, it is preferable to correct the timing deviation by expanding or contracting guard times included in all time-division channels. If the current timing is delayed and the timing is to be advanced, an instruction to temporarily shorten the guard time is given, and if the timing is to be delayed, an instruction to temporarily extend the guard time is given. Send to the processing unit 209 .

The downlink transmission buffer 210 is a buffer that temporarily stores downlink mobile unit control information, and temporarily makes the data wait until the edge side mobile unit control device 22 can accept the data.

FIG. 10 is a diagram showing an example of the device configuration of the fixed radio station 13 and the mobile radio station 23 of this embodiment.

The fixed radio station 13 and the mobile radio station 23 can have the same hardware configuration.

The network interface unit 301 is a device that communicates with the center-side mobile unit control device 11 or the edge-side mobile unit control device 22 by wire or wirelessly according to a predetermined communication method. , data link layer, and MAC (Medium Access Control) layer. A commercially available chip or board having a modem function can be used. It corresponds to the network interface unit 101 in FIG. 8 and the network interface unit 201 in FIG.

The radio control calculation unit 302 performs frame-based radio control such as resource allocation management and message transmission inside the fixed radio station 13 and the mobile radio station 23, and can be realized by a calculation device such as a CPU. The radio control calculation unit 302 corresponds to the time division channel control unit 103 and the initial access processing unit 108 in FIG. 8, and corresponds to the buffer reading processing unit 203, the time division channel control unit 207 and the initial access processing unit 208 in FIG. .

The wireless digital signal processing unit 303 can be realized by an arithmetic device suitable for real-time processing such as FPGA. The wireless digital signal processing unit 303 corresponds to the wireless digital signal transmission processing unit 104 and the wireless digital signal reception processing unit 107 in FIG. 8, and corresponds to the wireless digital signal transmission processing unit 204 and the wireless digital signal reception processing unit 209 in FIG. do.

The wireless analog signal processing unit 304 has a conversion function between a baseband digital signal and a high-frequency analog signal, and includes an A/D (analog-to-digital) converter, a D/A (digital-to-analog) converter, a filter, a mixer, an amplifier, and the like. A wireless communication module having Since this embodiment assumes TDD (Time Division Duplex) communication, a switch for switching between transmission and reception is provided on the antenna side. High frequency analog signals are transmitted and received via antennas (14, 24).

Of the wireless control arithmetic unit 302 , the wireless digital signal processing unit 303 and the wireless analog signal processing unit 304 , programs related to programmable devices are stored in the program storage memory 310 . Even if the power is turned off, the stored contents of the memory are not cleared, and the memory contents are written to the wireless control calculation unit 302, the wireless digital signal processing unit 303, and the wireless analog signal processing unit 304 immediately after the power is turned on. It is desirable to use

The processor 311 that executes the boot sequence controls the writing of the program when starting the device. After power-on, the processor 311 executes a boot sequence to boot the device. During the boot sequence, the contents of the program stored in the program storage memory 310 are written to the wireless control arithmetic unit 302, the wireless digital signal processing unit 303, and the wireless analog signal processing unit 304 through the data transmission bus 309. FIG. The processor 311 can be realized by an arithmetic device such as a CPU and a storage device.

A buffer 305 is a storage area provided in the network interface unit 301 and is composed of a volatile memory. The buffer 305 stores an information sequence transmitted from the center-side mobile unit control device 11 to the fixed radio station 13, an information sequence transmitted from the edge-side mobile unit control unit 22 to the mobile radio station 23, and an information sequence transmitted in the reverse direction. Temporarily accumulate information series. The buffer 305 corresponds to the downstream transmission buffer 102 and the upstream transmission buffer 109 in FIG. 8, and corresponds to the upstream transmission buffer 202 and the downstream transmission buffer 210 in FIG.

A buffer 306 is a buffer that transfers data between the wireless control arithmetic unit 302 that operates at frame timing and the wireless digital signal processing unit 303 that operates in real time, and is composed of a volatile memory. The information bit sequence to be transmitted in each slot in the frame is written from the radio control calculation unit 302 to the radio digital signal processing unit 303 . The information bit sequence obtained by decoding the radio signal for each slot in the frame and the error detection result by CRC are written from the radio digital signal processing unit 303 to the radio control calculation unit 302 .

Working memories 307 and 308 are working memories used by the radio control calculation unit 302 and the radio digital signal processing unit 303, respectively, and contain information necessary for radio control and radio signal processing, frequency hopping sequences for each fixed radio station identifier, The preamble sequences are written in working memories 307 and 308 and referred to by themselves. The working memories 307 and 308 are composed of volatile memories.

The frequency hopping sequences and preamble sequences for all fixed radio station identifiers refer to a table generated when the radio control calculation unit 302 is activated or written in the program storage memory 310 as part of the program. It writes to the working memory 307 and the preamble sequence to the working memory 308 .

FIG. 11 is a diagram showing an example of time-division channels when two types of preamble sequences of this embodiment are applied.

In FIG. 3, the preamble sequences in the time-division channel are collectively expressed as one, but in FIG. placed in front.

The length of the first preamble and the length of the second preamble are fixed, respectively, but the lengths of both may not be the same. It is sufficient if the series itself is shared.

The first preamble and the second preamble are transmittable from the fixed radio station 13 and the mobile radio station 23, and are time-multiplexed with the data signal in the time-division channel in which the data signal to be transmitted exists. That is, there is no time division channel that only transmits preambles. From this point of view, only the preamble transmitted from the fixed radio station 13 on the broadcast time-division channel is reliably transmitted for each frame.

The first preamble is used to estimate the start timing of the time division channel and the start timing of the frame. The mobile radio station 23 performs a sliding correlation operation on the received signal using its own first preamble sequence. It is determined that it is the beginning of one preamble, that is, at least the beginning of the time-division channel.

The second preamble is a sequence dependent on the fixed radio station identifier and has two uses. The first use is to search for the fixed radio station 13 that gives the preamble received with the strongest power in the initial state where the mobile radio station 23 has not started communication with any fixed radio station 13 . The second application is that the mobile radio station 23 is assigned a time-division channel from one of the fixed radio stations 13, and the fixed radio station 13, which is the transmission source of the first preamble, is the fixed radio station 13 whose synchronization is to be maintained. It is used to verify whether

A first use of the second preamble will be described.

In a first application, a fixed radio station group having the strongest received power among received second preambles of various fixed radio station groups is identified, and furthermore, the received power of the second preamble is determined between frequency subchannels. The fixed wireless station 13 in the group is further specified by comparison.

In order to implement the above, it is first necessary to identify whether the first preamble is the preamble transmitted on the broadcast time division channel. If there is a fixed radio station 13 that does not transmit a preamble in a channel other than the broadcast time-division channel and the cross-correlation value is low as a result of preamble cross-correlation calculation, is the correlation value low because the preamble has not been transmitted? It is not possible to determine whether the correlation value has decreased due to propagation attenuation. Then, there arises a problem that the fixed radio station 13, which is selected if it is transmitting a radio signal, is not selected because it is not transmitting a signal.

For example, the first preamble transmitted on the broadcast time-division channel has a low cross-correlation sequence with the first preambles transmitted on other time-division channels, and is the same for all fixed radio stations 13 in the system. If the preamble sequence is used, the beginning of the broadcast time division channel can be detected based on the cross-correlation value by making the first preamble used in the sliding correlation a sequence dedicated to the broadcast time division channel.

It can be estimated that the timing delayed by the first preamble length from the start timing of the broadcast time-division channel acquired in this process is the start timing of the second preamble.

With the head timing of the second preamble as the head and the section of the second preamble length as the cross-correlation calculation section, calculate the cross-correlation between the received signal and the second preamble sequence of various fixed radio station groups, Select the fixed radio station group associated with the second preamble sequence with the highest cross-correlation value.

Further, the cross-correlation with the second preamble sequence of the selected fixed radio station group is calculated on all frequency sub-channels in this cross-correlation calculation interval, and the frequency sub-channel with the highest cross-correlation value is selected.

In the selected frequency subchannel, the data signal immediately following the second preamble sequence is decoded to extract the information elements of the broadcast time division channel. The fixed radio station identifier indicated in the information element is the first use of the second preamble, namely the fixed radio station search result.

A second use of the second preamble will be described.

The second application assumes that the mobile radio station 23 has once established synchronization with a fixed radio station 13 . However, the frame start timing and the time-division channel start timing are shifted due to clock shift between radio stations over time and movement of the mobile radio station 23 .

In order to monitor the head timing deviation, the mobile radio station 23 considers the frequency hopping sequence of the fixed radio station 13 with which synchronization has been established, and determines the frequency sub-channel where the annunciation time division channel of the synchronization target fixed radio station 13 is transmitted. After selecting a channel, the first preamble sequence is used to detect the leading timing of the broadcast time-division channel.

When there is no head timing deviation, the head timing of a certain frame is expected to be the timing delayed by the frame length from the head of the previous frame. On the other hand, when there is a deviation, the expected timing and the observed timing are back and forth. This deviation is always corrected. For example, the shift can be corrected by extending or shortening the guard time of the time-division channel following the broadcast time-division channel.

In the above processing, it should be noted that since there are a plurality of fixed radio stations 13 that transmit the first preamble on the same frequency subchannel, the reception timing of the first preamble sequence of the unexpected fixed radio station 13 is correct. It's about judging that it's time. As a result, correction of the guard time is erroneous and data signals are extracted at erroneous timing, making it difficult to extract correct data signals.

By taking advantage of this property, the second preamble can be used to verify whether or not the fixed radio station 13, the source of the first preamble, is as expected. Specifically, as a result of the cross-correlation calculation for the first preamble, cross-correlation maxima occur at a plurality of timings. , the cross-correlation value is low except at the reception timing of the second preamble transmitted by the expected fixed radio station 13 .

<Example 2>
In the first embodiment, all fixed radio stations 13 and mobile radio stations 23 belong to the same system. This embodiment shows an example in which different systems to which the present invention is applied share the same space.

When fixed radio stations 13 of different systems exist nearby and the orthogonality of mutual frequency hopping is maintained, the same frequency hopping matrix (FIG. 2) is prepared for both systems, and fixed to one system, for example. By assigning the least significant bit of the radio station identifier=0 and the same least significant bit=1 to the other system, the frequency hopping sequences are orthogonal at least between the systems. This method can ensure orthogonality between systems, but reduces the number of fixed radio stations 13 in a fixed radio station group that can maintain orthogonality within the system, from 16 to 8 in the example shown in FIG. However, if the frame and time-division channel start timings are not synchronized between systems, the orthogonality of the frequency hopping sequences is not strictly ensured. For this reason, it is desirable to synchronize timing between systems if possible.

When maintaining the number of fixed radio stations 13 in a fixed radio station group capable of maintaining orthogonality within the system, the upper bits of the fixed radio station identifier, which is the identifier of the fixed radio station group, are further subdivided into a bit range indicating the system. By defining (higher order bits) and a bit range (lower order bits) indicating a fixed radio station group within the system, the cross-correlation between the second preambles can be reduced between systems. As for the first preamble, a sequence with a low cross-correlation between systems may be defined for the broadcast time-division channel and others.

In this case, a system identifier corresponding to both the value of the bit range indicating the system and the value used to specify the series of the first preamble is added to the information element of the broadcast time-division channel in FIG. Alternatively, information equivalent to the system identifier may be transmitted as part of the fixed radio station identifier already included in the information element of the broadcast time division channel. If system identifiers are preset for the fixed radio station 13 and the mobile radio station 23 and are not changed during operation, there is no need to report the system identifiers through the time-division channel for reporting.

The operation method described above can be used to maintain orthogonality between systems or to maintain orthogonality within a fixed radio station group within a system at the expense of orthogonality between systems, depending on the system design concept. .

<Example 3>
Embodiments 1 and 2 show methods for synchronizing the timing of the mobile radio station 23 based on the signal transmitted by the fixed radio station 13 . By applying this method, synchronization is possible even between fixed radio stations 13 .

In order to achieve this, an observation frame is defined in which no radio signal is transmitted to each fixed radio station 13, and the annunciation time-division channels of other fixed radio stations 13 are observed in this frame. In other words, although the fixed radio station 13 normally operates as the fixed radio station 13, it operates in the same manner as the receiving side of the mobile radio station 23 only for the frame. However, although the fixed radio station 13 does not transmit radio signals in the observation frame, the time division channel serial numbers for selecting frequency subchannels for transmitting radio signals from the frequency hopping sequence are counted in the same manner as when transmitting radio signals. Keep it up. This is because the orthogonality of the frequency hopping sequences is based on the premise that all fixed radio stations 13 count up the time division channel serial number at the same time.

For each fixed radio station 13, the identifier of the fixed radio station 13 to be a synchronization target is set in advance at initial setting at startup or set from a maintenance terminal outside the system. However, at least one fixed radio station 13 is defined as a synchronization master in the system. The fixed radio station 13 as a synchronization target is not set as the synchronization master fixed radio station 13 . Also, it is not necessary to define an observation frame for the fixed radio station 13 that is the synchronization master.

The operation of synchronization between fixed radio stations 13 is basically the same as the reception and analysis operation of mobile radio station 23 . For example, it is the fixed wireless station search and the maintenance of the synchronization state illustrated in FIG. However, since the fixed radio station 13 as the synchronization target is determined, the fixed radio station search ignores the fixed radio stations 13 other than the target. Also, unlike the mobile radio station 23, transmission is not performed on the time-division channel for initial access after the fixed radio station search is completed.

In order to realize the above operations, the fixed radio station 13 must be equipped with the functions of the mobile radio station 23, except for radio signal transmission.

As described above, according to the embodiment of the present invention, the mobile radio station 23 uses the preamble signal to communicate between radio stations (between the fixed radio station 13 and the mobile radio station 23 or between the fixed radio stations 13). ), the frequency hopping sequences are orthogonalized and the same preamble signal is used in a plurality of fixed radio stations 13 forming a group. Since overlapping of frequency hopping sequences is allowed in some or all time division channels and different preamble signals are used, the preamble transmitted by the fixed radio station 13 connected to the mobile radio station 23 and the same frequency subchannel are used. Since the cross-correlation with the preamble transmitted on the same frequency subchannel by another fixed radio station 13 to be used is low, erroneous detection of the preamble of another fixed radio station 13 can be reduced in the cross-correlation calculation in the mobile radio station 23. . Also, by applying the above-described radio communication system to radio train control, for example, if the radio wave environment changes, a signal transmitted from a radio base station that should not be received originally can Even if the signal is detected by , it is possible to discriminate it from the signal transmitted from the radio base station that should be originally received, and highly reliable train control can be realized.

Also, by applying such a radio communication system to communication between radio base stations to be synchronized, it is possible to achieve synchronization between those radio base stations. That is, the radio base station defines an observation frame in which no radio signal is transmitted, and observes the annunciation time-division channels of other radio base stations in this frame. In other words, the radio base station operates in the same manner as the receiving side of the onboard radio station only for the frame. However, although the radio base station does not transmit radio signals in the observation frame, the time division channel serial number for selecting the frequency subchannel for transmitting radio signals from the frequency hopping sequence counts up in the same way as when transmitting radio signals. Keep This is because the orthogonality of frequency hopping sequences is based on the premise that all ground base stations simultaneously count up the time division channel serial numbers. For each radio base station, the identifier of the radio base station to be a synchronization target is set in advance at the time of startup or from a maintenance terminal outside the system. However, at least one wireless base station is defined as a synchronization master in the system. A synchronization target wireless base station is not set for the synchronization master wireless base station. Also, it is not necessary to define an observation frame for the synchronization master radio base station.

The identifier of the fixed radio station 13 is composed of a group identifier for uniquely identifying the group and an intra-group identifier for uniquely identifying the fixed radio station 13 within the group. Since the frequency hopping sequence is determined based on the intra-group identifier, the preambles transmitted from the fixed radio stations 13 define groups of fixed radio stations 13 that do not overlap in each frequency subchannel in the mobile radio station 23. can. By grouping the fixed radio stations 13 arranged in the vicinity into the same group, erroneous detection of the preamble in the mobile radio station 23 can be reduced.

Also, the fixed radio station 13 and the mobile radio station 23 connected to the fixed radio station 13 use the time division channel determined according to the frequency hopping sequence selected based on the identifier of the fixed radio station 13, Since the preamble signal selected based on the identifier of the fixed radio station 13 and the mobile unit control information are time-multiplexed and transmitted, the reception timing of the preamble can be detected for each time-division channel. Therefore, the fixed radio station 13 can correctly receive data signals from the mobile radio station 23 having different transmission sources and different radio propagation distances for each time-division channel.

The preamble signal is a combination of the signal of the first preamble sequence and the signal of the second preamble sequence. 23, and the second preamble sequence is selected based on the identifier of the fixed radio station 13, facilitating time-division channel head timing detection with the common first preamble within the radio communication system, With the second preamble, it can be verified whether the fixed radio station 13 that transmitted the first preamble is correct. Therefore, erroneous detection of timing due to the preamble can be reduced.

In addition, the fixed radio station 13 stores the identifier of the fixed radio station 13 and the time division channel number for associating each time division channel with the reading position of the frequency hopping sequence. , the mobile radio station 23 can easily identify the position of the received time-division channel in the frequency hopping sequence.

In addition, announcing time-division channels are arranged at the same position within a frame among all the fixed radio stations 13 in the radio communication system. Since the serial number is used, the frequency hopping sequence and the preamble sequence receivable by the fixed radio station 13 can be selected at any time by the mobile radio station 23 receiving the broadcast time-division channel transmitted periodically.

Further, the preamble signal transmitted on the broadcast time division channel is a preamble signal of a sequence having a low cross-correlation with the preamble signal transmitted on the time division channel other than the broadcast time division channel, and Since the preamble signal of the same preamble sequence is used for all the fixed radio stations 13, the mobile radio station 23 can easily determine that the start timing of the time division channel detected by the first preamble is the broadcast time division channel. can be identified.

Further, when fixed radio station 13 receives a connection request, fixed radio station 13 uses the downlink time-division channel allocated to mobile radio station 23 to transmit the allocation result. In addition, it is possible to communicate with an appropriate fixed radio station 13 according to the radio communication state of each fixed radio station 13 .

It should be noted that the present invention is not limited to the embodiments described above, but includes various modifications and equivalent configurations within the scope of the appended claims. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to those having all the described configurations. Also, part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Moreover, the configuration of another embodiment may be added to the configuration of one embodiment. Further, additions, deletions, and replacements of other configurations may be made to a part of the configuration of each embodiment.

In addition, each configuration, function, processing unit, processing means, etc. described above may be realized by hardware, for example, by designing a part or all of them with an integrated circuit, and the processor realizes each function. It may be realized by software by interpreting and executing a program to execute.

Information such as programs, tables, and files that implement each function can be stored in storage devices such as memories, hard disks, SSDs (Solid State Drives), or recording media such as IC cards, SD cards, and DVDs.

In addition, the control lines and information lines indicate those considered necessary for explanation, and do not necessarily indicate all the control lines and information lines necessary for mounting. In practice, it can be considered that almost all configurations are interconnected.

11... Center side moving body control device
DESCRIPTION OF SYMBOLS 12 Backbone network 13 Fixed radio station 14 Antenna attached to fixed radio station 21 Mobile 22 Edge-side mobile body control device 23 Mobile radio station 24 Antenna on mobile side 101 Network interface unit 102 Mobile body Control information downstream transmission buffer 103 Time-division channel control unit 104 Radio digital signal transmission processing unit 105 Radio analog signal transmission/reception processing unit 106 Fixed radio station management information 107 Radio digital signal reception processing unit 108 Initial access processing unit 109 Up-transmission buffer for mobile control information 201 Network interface unit 202 Up-transmission buffer for mobile control information 203 Buffer reading processing unit 204 Wireless digital signal transmission processing unit 205 Wireless analog signal transmission/reception processing unit 206 Time Division channel management information memory 207 Time division channel control unit 208 Initial access processing unit 209 Wireless digital signal reception processing unit 210 Down transmission buffer for mobile unit control information 301 Network interface unit 302 Radio control calculation unit 303 Radio Digital signal processing unit 304 --- Wireless analog signal processing unit 305 --- Buffer 306 used for communication with an external device via the network interface unit --- Buffer 307 for transferring data between the wireless control computing unit and the wireless digital signal processing unit Working memory 308 of wireless control arithmetic unit Working memory 309 of wireless digital signal processing unit Data transmission bus 310 Program storage memory 311 Processor for executing boot sequence

Claims (8)

A radio communication method in a radio communication system for two-way transmission of mobile control information using frequency-hopping time-division channels between a fixed radio station and a mobile radio station,
The fixed radio station identifier is composed of a group identifier for uniquely identifying a group and an intra-group identifier for uniquely identifying a fixed radio station within the group,
the mobile radio stations use preamble signals to synchronize timing among the radio stations;
A plurality of fixed radio stations that are close to each other and that constitute the group use preamble signals obtained by orthogonalizing frequency hopping sequences determined based on the intra-group identifier ,
between fixed radio stations in different groups, allowing overlapping of frequency hopping sequences in some or all of the time division channels and using different preamble signals ;
The fixed radio station and the mobile radio station connected to the fixed radio station use the time-division channel determined according to the frequency hopping sequence selected based on the identifier of the fixed radio station. time-multiplexing and transmitting a preamble signal selected based on the identifier and the mobile control information;
The preamble signal is a combination of a first preamble sequence signal and a second preamble sequence signal,
said first preamble sequence being the same for all said fixed radio stations and said mobile radio stations in said radio communication system;
A wireless communication method , wherein the second preamble sequence is selected based on an identifier of the fixed wireless station . The wireless communication method according to claim 1,
The fixed radio station transmits an identifier of the fixed radio station and a time division channel serial number for associating each time division channel with the reading position of the frequency hopping sequence to all the mobile radios connected to the fixed radio station. A radio communication method characterized by notifying a station. The wireless communication method according to claim 2,
A frame is defined by bundling multiple time division channels,
annunciation time-division channels are arranged at positions within the same frame among all fixed radio stations in the radio communication system;
A wireless communication method, wherein a serial number of the frame is used as a time-division channel number to be reported by the time-division channel for reporting. A wireless communication method according to claim 3,
At least one of the broadcast time-division channels is arranged in the frame,
The preamble signal transmitted on the broadcast time division channel is a preamble signal of a sequence having a low cross-correlation with the preamble signal transmitted on the time division channel other than the broadcast time division channel, and in the radio communication system a preamble signal of the same preamble sequence for all fixed radio stations. The wireless communication method according to claim 3,
An initial access time division channel for the mobile radio station to transmit a connection request requesting allocation of a time division channel for transmitting the mobile control information to the fixed radio station is arranged at a predetermined position within the frame. ,
When the fixed radio station receives the connection request, the fixed radio station allocates a time division channel for two-way transmission of the mobile control information to the mobile radio station, and uses a downlink time division channel among the allocated time division channels. and transmitting the results of allocation of time-division channels to the mobile radio station. A radio communication system for two-way transmission of mobile control information using frequency-hopping time-division channels between a fixed radio station and a mobile radio station,
A radio communication device that constitutes each of the mobile radio station and the fixed radio station includes one or more antennas, a radio signal processing unit that performs transmission and reception processing of radio signals, and controls transmission and reception of radio signals through a specific radio channel. and a radio transmission control unit for
The fixed radio station identifier is composed of a group identifier for uniquely identifying a group and an intra-group identifier for uniquely identifying a fixed radio station within the group,
the mobile radio stations use preamble signals to synchronize timing among the radio stations;
A plurality of fixed radio stations that are close to each other and that constitute the group use preamble signals obtained by orthogonalizing frequency hopping sequences determined based on the intra-group identifier ,
Fixed radio stations in different groups allow overlap of frequency hopping sequences in some or all time division channels and use different preamble signals ;
The fixed radio station and the mobile radio station connected to the fixed radio station use the time-division channel determined according to the frequency hopping sequence selected based on the identifier of the fixed radio station. time-multiplexing and transmitting a preamble signal selected based on the identifier and the mobile control information;
The preamble signal is a combination of a first preamble sequence signal and a second preamble sequence signal,
said first preamble sequence being the same for all said fixed radio stations and said mobile radio stations in said radio communication system;
A wireless communication system , wherein the second preamble sequence is selected based on the identifier of the fixed wireless station . A radio communication device constituting a fixed radio station that bi-directionally transmits mobile control information using a frequency-hopping time-division channel with a mobile radio station,
One or more antennas, a radio signal processing unit that performs transmission and reception processing of radio signals, and a radio transmission control unit that controls transmission and reception of radio signals through a specific radio channel,
The fixed radio station identifier is composed of a group identifier for uniquely identifying a group and an intra-group identifier for uniquely identifying a fixed radio station within the group,
A plurality of fixed radio stations that are close to each other and that constitute the group use preamble signals obtained by orthogonalizing frequency hopping sequences determined based on the intra-group identifier ,
Fixed radio stations in different groups allow overlap of frequency hopping sequences in some or all time division channels and use different preamble signals;
death,
a preamble signal selected based on the identifier of the fixed radio station and the mobile control information using a time division channel determined according to a frequency hopping sequence selected based on the identifier of the fixed radio station ; time-multiplexed and transmitted ,
The preamble signal is a combination of a first preamble sequence signal and a second preamble sequence signal,
said first preamble sequence being the same for all said fixed radio stations and said mobile radio stations in said radio communication system;
A radio communication apparatus , wherein the second preamble sequence is selected based on an identifier of the fixed radio station . A radio communication device constituting a mobile radio station that bi-directionally transmits mobile control information using a frequency-hopping time-division channel with a fixed radio station,
One or more antennas, a radio signal processing unit that performs transmission and reception processing of radio signals, and a radio transmission control unit that controls transmission and reception of radio signals through a specific radio channel,
The fixed radio station identifier is composed of a group identifier for uniquely identifying a group and an intra-group identifier for uniquely identifying a fixed radio station within the group,
A plurality of fixed radio stations that are close to each other and that constitute the group use preamble signals obtained by orthogonalizing frequency hopping sequences determined based on the intra-group identifier ,
Fixed radio stations in different groups allow overlap of frequency hopping sequences in some or all time division channels and use different preamble signals;
The wireless communication device
receiving a preamble signal transmitted by the fixed radio station and searching for a fixed radio station group;
selecting one fixed radio station in a frequency channel selected based on the received strength of the preamble signal of the searched fixed radio station group;
synchronizing timing with reference to the time division channel timing and frequency hopping sequence of the selected fixed radio station;
transmitting the same preamble signal as that of the fixed radio station with which synchronization has been established and the mobile unit control information within a time-division channel ;
The preamble signal is a combination of a first preamble sequence signal and a second preamble sequence signal,
said first preamble sequence being the same for all said fixed radio stations and said mobile radio stations in said radio communication system;
A radio communication apparatus , wherein the second preamble sequence is selected based on an identifier of the fixed radio station .

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