JP6463215B2 - Radio communication apparatus, radio communication control apparatus, and radio communication system - Google Patents

Description

  The present invention relates to a wireless communication device, a wireless communication control device, and a wireless communication system that perform wireless communication with a receiver on the road side.

  In recent years, a wireless communication system that performs communication between a vehicle traveling on a highway or a general road and a roadside machine has been studied. In particular, in the field of automatic driving of automobiles for the purpose of reducing driver's load and the like, distribution of control information using wireless communication technology in addition to sensing technology using radar and camera images is being studied. When utilizing wireless communication for automatic operation, it is required to ensure a certain communication quality in addition to security of communication contents. Technologies for improving the quality of wireless communication include diversity, error correction, and retransmission. Specifically, it is necessary to consider the application of retransmission techniques such as continuous transmission, which is a kind of time diversity, and repeatedly transmits the same data, ARQ (Automatic Repeat Request), and HARQ (Hybrid ARQ).

  Application of IEEE802.11p based on IEEE (Institute of Electrical and Electronics Engineers) 802.11a used in wireless LAN (Local Area Network) is being studied for vehicle-to-vehicle communication and road-to-vehicle communication. IEEE 802.11p uses OFDM (Orthogonal Frequency Division Multiplexing) transmission, which is also called orthogonal frequency division multiplexing. Compared with indoor communication in which wireless LAN is widely used, there is a concern that a delayed wave having a longer delay time may arrive in a multipath delayed wave in outdoor communication. As a countermeasure, 802.11p uses a longer GI (Guard Interval) as compared to 802.11a. In 802.11p, use of a 5.8 GHz band or a 5.9 GHz band is being studied. On the other hand, in Japan, communication systems using the 700 MHz band have been studied in ARIB (Association of Radio Industries and Businesses) STD T-109, and the use of OFDM is assumed. As a communication system using the 700 MHz band, for example, in road-to-vehicle communication for communicating between a base station installed on the roadside and a vehicle or vehicle-to-vehicle communication performed between vehicles, information related to safe driving support is provided. An intelligent transportation system is assumed. In the 700 MHz band transmission, since the number of channels that can be used is small, particularly efficient transmission and establishment of communication quality are required.

  In a system with GI or CP (Cyclic Prefix) added, such as OFDM, regardless of whether the delayed wave is artificial or not, a delayed wave with a delay time of about GI or CP is received from the preceding wave without significant degradation. In some cases, however, the reception quality can be further improved by the delay diversity effect. However, even if OFDM is used, communication quality cannot be ensured if the mobile station stops in an environment where the delay time, power, and phase relationship of each path is poor as in the single carrier transmission method.

  Regarding a road-to-vehicle communication system, the following Patent Document 1 discusses a system that performs transmission diversity for the purpose of improving downlink communication quality between road vehicles. The aim is to improve the communication quality by controlling the frequency of each transmitting base station so as to correct the frequency fluctuation due to the Doppler effect.

  In Patent Document 2 below, a method of performing delay diversity is studied. The purpose is to prevent a drop in the received electric field that occurs when signals transmitted from the base stations are in the same level and in opposite phase in the vicinity of an intermediate point between the base stations.

JP 2001-24576 A Japanese Patent No. 3180733

  However, in Patent Document 1, in the 5 GHz band and 700 MHz band, the effect of correction by the Doppler effect cannot be obtained at the moving speed of the vehicle, and separate frequency correction is necessary for a vehicle traveling in the opposite direction on the opposite lane. There was a problem. Further, in Patent Document 2, since it is affected by a delayed wave other than an artificial delayed wave generated by delay diversity, there is a possibility that communication quality cannot be ensured when a mobile station stops at a point where the radio wave condition is bad. There was a problem that there was.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a wireless communication apparatus capable of obtaining a delay diversity effect.

In order to solve the above-described problems and achieve the object, a wireless communication apparatus according to the present invention includes a device information storage unit that stores position information of a wireless communication apparatus that performs transmission diversity cooperation. In addition, a reception position control unit that controls position information of a reception point indicating a position of a receiver that receives a transmission signal transmitted from the wireless communication apparatus is provided. In addition, a delay time control unit is provided that sets a delay time to be added to a transmission signal transmitted from the own apparatus based on the position information of the wireless communication apparatus that performs transmission diversity cooperation and the position information of the reception point. Further, a transmission signal generation unit that generates a transmission signal to be transmitted from the own apparatus is provided. In addition, a delay adding unit that adds a delay time set by the delay time control unit to the transmission signal generated by the transmission signal generating unit is provided. The delay time control unit calculates the difference between the reception time of the transmission signal from the other wireless communication device and the transmission signal from the own device in the receiver calculated from the distance between each wireless communication device and the reception point. Set the delay time to be an integer multiple of.

  According to the present invention, there is an effect that a delay diversity effect can be obtained.

The figure which shows the structural example of the radio | wireless communications system concerning Embodiment 1. FIG. 1 is a block diagram showing a configuration example of a roadside machine according to a first embodiment. The flowchart which shows the process which adds a delay time to the signal transmitted in the roadside machine concerning Embodiment 1, and transmits. Block diagram showing a configuration example of a roadside machine and a control station according to a second embodiment Block diagram showing a configuration example of a roadside machine according to the third embodiment The figure which shows the structural example of the radio | wireless communications system concerning Embodiment 4. FIG. Block diagram showing a configuration example of a roadside machine according to a fourth embodiment The figure which shows the hardware constitutions of each apparatus concerning Embodiment 1-4.

  Hereinafter, a radio communication device, a radio communication control device, and a radio communication system according to embodiments of the present invention will be described in detail based on the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram of a configuration example of a wireless communication system according to the first embodiment of the present invention. Specifically, a road-vehicle communication system in which roadside devices 1, 2, and 3 that are wireless communication devices and a mobile station 4 that is a receiver perform wireless communication will be described as an example. In the road-to-vehicle communication system, roadside devices 1 to 3 that perform wireless communication with the mobile station 4 are installed along the road. As an example, a case where the mobile station 4 travels between the roadside machine 1 and the roadside machine 2 and transmission diversity by delay diversity in which the same data is transmitted by the three roadside machines 1 to 3 will be described. Here, the same data refers to payload information processed in an upper layer (not shown) that provides services to the mobile station 4 in the road-to-vehicle communication system, and is an actual transmission waveform transmitted from the roadside devices 1 to 3. Some, for example, roadside machine-specific reference signals and ID information do not have to be the same between roadside machines.

  In addition, in FIG. 1, although the code | symbol 1-3 is provided to the part written as the roadside machine on the structure of a figure, the antenna part is also included in the roadside machines 1-3.

  In the road-to-vehicle communication system, a service is provided to the mobile station 4 which is an on-road station on the road. However, since the road is constructed in a linear shape, the service is expanded on the area like a mobile phone system. However, it is necessary to ensure the reception quality of the mobile station 4 in a linear region with a limited spatial extent. Therefore, in the road-to-vehicle communication system, for each reception point indicating the position of the mobile station 4 on the road that receives the signals transmitted from the roadside devices 1 to 3, the reception time of the direct wave coming from the roadside devices 1 to 3 is set. It is relatively easy to control.

  Also, although common to OFDM and single carrier transmission systems, the difference in reception time at the mobile station 4 of each signal transmitted from the roadside devices 1 to 3 is performed in the reception processing of the signal received at the mobile station 4. When the sampling interval at the time of sampling or an integer multiple of the symbol period of the signal transmitted from the roadside devices 1 to 3 is used, the mobile station 4 uses the correlation detection or the like due to the configuration of the equalizer used in the reception process. The accuracy of transmission path estimation may improve. On the other hand, in the mobile station 4, depending on the reception time of each signal transmitted from the roadside devices 1 to 3 and the relative value of the received power, a frequency that causes a deep drop in the frequency characteristic of the received power is generated. The signal-to-noise ratio (SNR) after correction by the converter may deteriorate and affect reception quality.

  In the case of OFDM, pilot signals arranged in a time-frequency manner may be used. In the mobile station 4, the propagation path estimation of the data part other than the pilot signal is often calculated by interpolation from the channel estimation value of the pilot signal part. However, if the pilot signal is sparsely arranged, the interpolation error becomes large. Can be considered. The reception quality of the mobile station 4 can be improved by performing the delay time and power control in the vicinity of the frequency where the pilot signal is arranged so that the frequency characteristic interpolation accuracy is improved by the roadside devices 1 to 3 on the transmission side. I can expect.

  Here, the reception times of the direct waves of the signals transmitted from the roadside devices 1 to 3 at the mobile station 4 will be organized. The distance between the roadside machine 1 and the roadside machine 2 is defined as a distance L (1, 2), the distance between the roadside machine 1 and the mobile station 4 is the distance l (1, i), and the distance between the roadside machine 2 and the mobile station 4 is When the distance is defined as the distance l (2, i), when the antenna height of the roadside devices 1 to 3 is sufficiently smaller than the distance L (1, 2), the approximation according to the equation (1) is established.

  L (1,2) = l (1, i) + l (2, i) (1)

  On the other hand, the reception time a (1) of the signal transmitted from the roadside device 1 and reaching the mobile station 4 is expressed by the following equation (2), where the delay time added to the transmission signal by the roadside device 1 is the delay time Δt (1). Can be expressed as In addition, c shows the speed of light.

  a (1) = l (1, i) / c + Δt (1) (2)

  When it is assumed that the reception time difference of the signals transmitted from the roadside devices 1 and 2 in the mobile station 4 is an integral multiple of the sampling interval T0, this condition is transmitted from the roadside device 2 and reaches the mobile station 4. If the signal reception time is a (2) and the integer is m (i), it can be expressed by equation (3).

  a (1) -a (2) = m (i) T0 (3)

  Assuming that the delay time added to the transmission signal by the roadside device 2 is the delay time Δt (2), the equation (3) is satisfied and m (i) T0 is in a range not exceeding the guard interval length of the transmission signal. The roadside machine 1 controls the delay time Δt (1), and the roadside machine 2 controls the delay time Δt (2).

  The delay time may be determined for the roadside machine 3 in the same manner as the roadside machines 1 and 2. First, the reception time a (2) of the signal transmitted from the roadside device 2 and reaching the mobile station 4 can be expressed by Expression (4).

  a (2) = l (2, i) / c + Δt (2) (4)

  When the distance between the roadside machine 2 and the roadside machine 3 is defined as the distance L (2, 3) and the distance between the roadside machine 3 and the mobile station 4 is defined as the distance l (3, i), the antenna height of the roadside machines 1 through 3 is When it is sufficiently smaller than the distance L (2, 3), the approximation according to the equation (5) is established.

  l (3, i) = l (2, i) + L (2,3) (5)

  When the mobile station 4 is located between the roadside machine 1 and the roadside machine 2 as shown in FIG. 1, the reception time a (3) at which the mobile station 4 receives the signal transmitted from the roadside machine 3 is expressed by the equation (6). Can be expressed as

  a (3) = l (2, i) / c + L (2,3) / c + Δt (3) (6)

  Here, the equation (4) is transformed into the following equation (4 ′).

  a (2) −Δt (2) = 1 (2, i) / c (4 ′)

  By substituting equation (4 ′) into equation (6), a (3) can be expressed in the form of equation (7).

  a (3) = a (2) −Δt (2) + L (2,3) / c + Δt (3) (7)

  Therefore, by installing the roadside devices 1 to 3 so that the distance between the roadside devices becomes an optical path length corresponding to an integral multiple of the sampling interval T0, the delay time Δt (2) and the delay time Δt (3) The difference is also an integral multiple of the sampling interval T0, and the reception time can be easily controlled.

  In the roadside devices 1 to 3, the delay time added to the signal to be transmitted to the mobile station 4 is the distance l (1, i), l (2, i), which is the position parameter of the mobile station 4 for each roadside device. Set based on l (3, i). Actually, in general, the position of the mobile station 4 in the roadside devices 1 to 3 is not known. Therefore, in the roadside devices 1 to 3, the distance l (1, i), which is a position parameter, is assumed assuming a reception point indicating a position on the road where the mobile station 4 receives the signal transmitted from the roadside devices 1 to 3. l (2, i), l (3, i) are tentatively determined, and the reception time difference at which the mobile station 4 receives the signals transmitted from the roadside devices 1 to 3 at an assumed reception point is an integral multiple of the sampling interval T0. Control to become.

  In this case, the mobile station 4 is expected to improve the reception quality at the assumed reception point, but the reception quality may be deteriorated at reception points other than the assumed reception point. As a countermeasure, the roadside devices 1 to 3 repeatedly transmit the same data for each transmission opportunity for transmitting a transmission signal, and change the assumed location parameter for each transmission opportunity, so that the mobile station 4 receives reception with poor reception quality. It is good also as a structure operated so that the situation where a point is always in a bad state may be avoided.

  As described above, the roadside devices 1 to 3 can improve the reception quality of the mobile station 4 by controlling the delay time added to the transmission signal by each roadside device according to the position of the mobile station 4. it can. In addition, the roadside devices 1 to 3 continuously transmit data so as to change the transmission timing by changing the delay time for each transmission opportunity, so that the reception quality of the mobile station 4 at each reception point between the roadside devices. Can be averaged over time, and data can be normally transmitted to many reception points including the position of the mobile station 4.

  In the above description, transmission diversity using three roadside devices is taken as an example, but the number of roadside devices performing transmission diversity may be two or four, and is not particularly limited. Moreover, although the position of the mobile station 4 was demonstrated as between the roadside machine 1 and the roadside machine 2, it is an example and is not specifically limited.

  It continues and the structure of the roadside machines 1-3 is demonstrated. Since the roadside machines 1 to 3 have the same configuration, the roadside machine 1 will be described. FIG. 2 is a block diagram of a configuration example of the roadside machine 1 according to the first embodiment.

  In the roadside machine 1, the roadside machine information storage unit 11 manages the position information of the roadside machine whose position is fixed together with the roadside machine 1 in cooperation with transmission diversity. The position information of the roadside machine 1 may be included in the position information of the roadside machine linked to the roadside machine 1. The position information of each roadside machine may be written in the roadside machine information storage unit 11 by some means when the roadside machine is installed, or is distributed from a higher-level control device of the network (not shown in FIG. 1), and the roadside machine information storage unit 11 may be recorded.

  The reception position control unit 12 holds the distance l (1, i), which is a position parameter, or the position information of the mobile station 4 that replaces the distance, and is the transmission destination of the signal transmitted from the roadside device 1. The distance to the reception point indicating the position of the mobile station 4 that receives the transmission signal from the machine 1 is managed. When the position of the mobile station 4 is known in some form, the reception position control unit 12 detects and notifies the position of the mobile station 4 by GPS (Global Positioning System) or a satellite positioning system similar to GPS in, for example, uplink data communication. If the roadside device 1 can detect the presence of the mobile station 4 at a specific position using sensors, for example, radar, lidar, camera, etc., the detected position is set as the position of the mobile station 4 To do. When the position of the mobile station 4 is unknown as described above, the reception position control unit 12 assumes a reception point between the roadside machines based on the position information of each roadside machine in the roadside machine information storage unit 11, and the mobile station The position 4 may be used. When the signal is transmitted a plurality of times from the roadside device 1, the reception position control unit 12 changes the position of the reception point assuming a different reception point for each transmission opportunity of the transmission signal. Control can be made so that bad reception points do not continue as bad.

  As described above, the delay time control unit 13 is based on the position information of each roadside machine that performs transmission diversity cooperation acquired from the roadside machine information storage unit 11 and the position information of the reception point acquired from the reception position control unit 12 as described above. In detail, in the mobile station 4, the received signal from the roadside devices 2 and 3 and the roadside device 1 from the roadside device 1 so that the reception time difference of the received signals from each roadside device is an integral multiple of the sampling interval T 0. The delay time Δt (1) added to the transmission signal transmitted from the roadside device 1 is set so that the reception time difference between the received signals becomes an integral multiple of the sampling interval T0. In addition, when the delay time control unit 13 acquires position information of different reception points for each transmission opportunity of the transmission signal from the reception position control unit 12, the delay time control unit 13 sets a different delay time Δt (1) for each reception point. In addition, when adopting a signal format to which GI or CP is added such as an OFDM signal, the delay time control unit 13 cyclically delays a transmission signal so as to be CDD (Cyclic Delay Diversity) in cooperation with other roadside units. A delay time for transmission may be set.

  The transmission signal generation unit 14 generates a transmission signal transmitted from its own apparatus, and has a transmission waveform in accordance with an OFDM signal, particularly, a transmission scheme in the IEEE802.11p or 700 MHz band.

  The delay adding unit 15 adds the delay time set by the delay time control unit 13 to the transmission signal generated by the transmission signal generating unit 14 and transmits the transmission signal from the antenna 16 to the mobile station 4. In addition, the delay adding unit 15 may transmit the transmission signal by a cyclic delay with the delay time set by the delay time control unit 13. In the mobile station 4 that performs the process of synthesizing the delayed wave, the relative power and phase difference between the received signals affect the channel frequency characteristics and the synchronization performance of the modem. Therefore, the delay adding unit 15 may perform control of transmission power and phase so as to prevent the mobile station 4 from causing a large drop in channel frequency characteristics of received power. Further, the delay adding unit 15 may substitute phase control by adding a slight frequency offset in the mobile station 4 for the purpose of time-varying the phase relationship of signals received from each roadside device.

  In the configuration of the roadside device 1 in FIG. 2, the case where the roadside device 1 performs the delay time control has been described as an example. However, a mechanism for cooperatively allocating transmission timing among a plurality of roadside devices is required. For example, in the roadside machines 1 to 3, when the roadside machine information storage unit 11 holds the position information of the roadside machines 1 to 3 including the own machine and other cooperation destinations, it is assumed that the same data is transmitted three times. Based on the position information of each roadside machine held in the roadside machine information storage unit 11, the delay time control unit 13 first transmits the roadside machine having the highest latitude value of the position information first, and the second time The roadside machine with the next highest latitude value in the location information transmits first, and the third time the roadside machine with the lowest latitude value in the location information sends first. Operate so that there is no delay time.

  Specifically, when the roadside devices 1 to 3 change the reception point of the mobile station 4 for each transmission opportunity, the reception points of the mobile station 4 are set between the roadside devices 1 and 2 at regular intervals from the roadside device 1 side. And 3 transmissions are performed at each reception point. In the first transmission, it is assumed that the roadside device 1 first transmits a signal. The roadside device 1 adds the specified delay time added by the first roadside device that is known to the roadside devices 1 to 3 as the delay time Δt (1). Next, the roadside device 2 that transmits a signal has known positions of the roadside devices 1 to 3 and the assumed reception point of the mobile station 4, and a specified delay time added by the roadside device that transmits first is known. Thus, the distance l (1, i) from the roadside device 1 to the mobile station 4 can be estimated, and the reception time a (1) at which the signal transmitted from the roadside device 1 reaches the mobile station 4 can be estimated. Therefore, in the roadside device 2, the delay time Δt (2) is set so that a (1) −a (2) = m (i) T0 for the reception time a (2) of the signal reaching the mobile station 4. . Similarly, the roadside device 3 sets the delay time Δt (3) so that a (1) −a (3) = m ′ (i) T0 for the reception time a (3) of the signal reaching the mobile station 4. Set. Note that m ′ (i) is an integer different from m (i). In the second transmission, assuming that the roadside device 2 first transmits a signal, the specified delay time added by the roadside device that the roadside device 2 transmits first is added as a delay time Δt (2). Thereafter, the operations of the roadside devices 3 and 1 that transmit signals next are the same as the operations of the roadside devices 2 and 3 in the first transmission.

  The process of each configuration described above will be described using a flowchart. FIG. 3 is a flowchart of a process of adding a delay time to a signal to be transmitted in the roadside device 1 according to the first embodiment and transmitting the signal. In the roadside machine 1, the delay time control unit 13 acquires the position information of the roadside machine from the roadside machine information storage unit 11, and acquires the position information of the reception point from the reception position control unit 12 (step S1). Based on the position information of the roadside device and the position information of the reception point, the delay time control unit 13 causes the reception time difference of the signals transmitted from each roadside device in the mobile station 4 to be an integral multiple of the sampling interval T0. Then, a delay time to be added to the transmission signal is set (step S2). The delay adding unit 15 adds the delay time set by the delay time control unit 13 to the transmission signal generated by the transmission signal generating unit 14 and transmits the transmission signal to the mobile station 4 via the antenna 16 (step S3). ).

  As described above, in the present embodiment, in the roadside devices 1 to 3, the mobile station 4 transmits from each roadside device based on the position information of the roadside devices 1 to 3 and the position information of the reception point of the mobile station 4. The delay time added to the transmission signal is set so that the reception time difference of the received signal is an integral multiple of the sampling interval T0. As a result, the mobile station 4 can obtain an efficient delay diversity effect. In addition, the roadside devices 1 to 3 change the delay time for each transmission opportunity, so that the drop in reception quality at a certain reception point in the mobile station 4 can be prevented. Also, even when non-artificial multipath waves are mixed, each delay wave arrives at the mobile station 4 with an additional delay amount due to the addition of the delay time, so that the drop in reception quality does not continue. As a result, the reception quality can be improved.

  In a wireless communication system using a wireless transmission system that adds a GI such as OFDM or a CP that performs the same function, a delay time is added to a transmission signal between the roadside devices 1 to 3 according to the position of the mobile station 4. Change the transmission time. Thereby, in the mobile station 4, since the reception waveform of the signal transmitted from the roadside devices 1 to 3 is different even at an intermediate point between the roadside devices 1 to 3, a significant drop in reception quality due to phase inversion is avoided. can do. Further, in the roadside devices 1 to 3, the delay time control unit 13 adjusts the transmission time for each reception point of the mobile station 4 existing between the roadside devices for each transmission opportunity of the transmission signal including the same information. By setting different delay times, the mobile station 4 can obtain an instantaneous fluctuation effect of the reception quality. In the roadside devices 1 to 3, since the delay time is controlled so that the reception time of the signal transmitted from the roadside devices 1 to 3 is relatively changed in the mobile station 4, the quality is poor when the mobile station 4 is stopped. The phenomenon that the state continues is avoided, and the reception quality at the mobile station 4 can be averaged.

Embodiment 2. FIG.
In the first embodiment, the delay time is controlled by the roadside devices 1 to 3, but in this embodiment, a control station other than the roadside device controls the delay time of each roadside device.

  FIG. 4 is a block diagram of a configuration example of the roadside machine 1a and the control station 5 according to the second embodiment. The configuration of the roadside machines 2a and 3a is the same as that of the roadside machine 1a. In the second embodiment, the roadside devices 1a, 2a, 3a cooperate in transmission diversity, and the roadside devices 1a, 2a, 3a and the control station 5 constitute a radio communication system.

  In this Embodiment, the control station 5 which is a radio | wireless communication control apparatus sets the delay time added to a transmission signal in the roadside machines 1a-3a, and outputs the information of delay time to the roadside machines 1a-3a. Information on delay time information is output to the roadside devices 2a and 3a via the network between the control station 5 and the roadside devices 1a to 3a. The network between roadside devices may be either wired or wireless. In the control station 5, the roadside machine information storage unit 21 has the same configuration as the roadside machine information storage unit 11 of the roadside machine 1, but manages position information about the roadside machines 1 a to 3 a. The reception position control unit 22 is the same as the reception position control unit 12 of the roadside machine 1. The delay time control unit 23 has the same configuration as that of the delay time control unit 13 of the roadside device 1, but sets the delay time for three devices to be added to the transmission signal in the roadside devices 1a to 3a that perform the cooperation of transmission diversity. .

  The delay time control unit 23 outputs delay time information set for the roadside devices 1a to 3a to the corresponding roadside devices 1a to 3a. In the delay time control unit 23, the process itself for setting the delay time of each roadside machine is the same as that of the delay time control unit 13 of the first embodiment. In the delay time control unit 23, the first embodiment is based on the position information of each roadside device that performs transmission diversity cooperation acquired from the roadside device information storage unit 21 and the position information of the reception point acquired from the reception position control unit 22. As with the delay time control unit 13, the delay time added to the transmission signal transmitted from each roadside device is set so that the reception time difference of the received signal from each roadside device is an integral multiple of the sampling interval T0 in the mobile station 4. To do. In addition, when the delay time control unit 23 acquires position information of different reception points for each transmission opportunity of the transmission signal from the reception position control unit 22, the delay time control unit 23 sets a different delay time for each reception point. In addition, when adopting a signal format to which GI or CP is added such as an OFDM signal, the delay time control unit 23 transmits a transmission signal by a cyclic delay so that each roadside unit cooperates to form CDD. Time may be set.

  However, since the delay time control unit 23 sets the delay times of the roadside devices 1a to 3a only by the delay time control unit 23, the receiver 4 receives the reception time a (1) of the signal transmitted from the roadside device 1a and the roadside. Difference in reception time a (2) of the signal transmitted from the machine 2a, reception time a (1) of the signal transmitted from the roadside machine 1a in the receiver 4 and reception time of the signal transmitted from the roadside machine 3a The reception time difference of a (3) and the reception time difference of the reception time a (2) of the signal transmitted from the roadside device 2a and the reception time a (3) of the signal transmitted from the roadside device 3a in the receiver 4 That is, the reception time difference between the roadside devices can be easily calculated. Therefore, the delay time control unit 23 can easily set the delay time for the roadside devices 1a to 3a so that the reception time difference between the roadside devices is an integral multiple of the sampling interval T0.

  In the roadside machine 1a, the roadside machine information storage unit 11, the reception position control unit 12, and the delay time control unit 13 are deleted from the roadside machine 1, and a delay time input unit 17 is added. The delay time input unit 17 receives input of delay time information set in the own device, that is, the roadside device 1 a from the control station 5, and outputs the delay time information to the delay adding unit 15. The processing of transmission signal generation unit 14 and delay addition unit 15 is the same as that in the first embodiment. The delay adding unit 15 adds the delay time input to the delay time input unit 17 to the transmission signal generated by the transmission signal generating unit 14 and transmits the transmission signal from the antenna 16 to the mobile station 4.

  As described above, in the present embodiment, the control station 5 sets the delay time of the roadside devices 1a to 3a and outputs the delay time information to each of the roadside devices 1a to 3a, and the roadside devices 1a to 3a Therefore, the transmission signal from the own device is added with the delay time set by the control station 5 and transmitted. Thereby, the effect similar to Embodiment 1 can be acquired, and also cost can be reduced as a system by simplifying the structure of the roadside machine installed in multiple numbers.

Embodiment 3 FIG.
In the first embodiment, the delay time is controlled by the roadside devices 1 to 3, but in this embodiment, the delay time of each roadside device is controlled by one roadside device.

  FIG. 5 is a block diagram of a configuration example of the roadside machine 1b according to the third embodiment. The configuration of the roadside machines 2a and 3a is the same as that of the roadside machine 1a of the second embodiment. In Embodiment 3, the roadside machine 1b is a master station and the roadside machines 2a and 3a are slave stations. In the third embodiment, the roadside devices 1b, 2a, and 3a cooperate in transmission diversity, and the roadside devices 1b, 2a, and 3a constitute a wireless communication system.

  In this embodiment, the roadside machine 1b of the master station controls the delay time added to the transmission signal in the roadside machine 1b and the roadside machines 2a and 3a of the slave stations, and outputs delay time information to the roadside machines 2a and 3a. To do. In the roadside machine 1b, the delay time control unit 13 is deleted from the roadside machine 1 and a delay time control unit 13b is added. The operation of the delay time control unit 13b performs the same processing as that of the delay time control unit 23 of the control station 5 according to the second embodiment. The delay time control unit 13b sets a delay time to be added to a transmission signal generated by each wireless communication device by itself for the wireless communication devices 1b, 2a, and 3a that perform transmission diversity cooperation. The delay time control unit 13b outputs the delay time information set for the roadside device 1b to the delay adding unit 15, and outputs the delay time information set for the roadside devices 2a and 3a to the respective roadside devices 2a and 3a. The delay time control unit 13b outputs information on delay time information to the roadside devices 2a and 3a via the network between the roadside devices. The delay time input unit 17 of the roadside devices 2a and 3a receives input of delay time information set in the own device from the delay time control unit 13b of the roadside device 1b, and outputs the delay time information to the delay adding unit 15 To do. The network between roadside devices may be either wired or wireless. In the roadside machine 1b, the operation of the other configuration other than the delay time control unit 13b is the same as that of each configuration of the roadside machine 1.

  In addition, about the roadside machine information memory | storage part 11, when managing the position information of the roadside machine 1b including the position information of the roadside machine 1b in the position information of the roadside machine linked with the roadside machine 1b, it may be the same as in the first embodiment. 1 does not include the position information of the roadside machine 1b, the third embodiment further includes the position information of the roadside machine 1b.

  As described above, in the present embodiment, the roadside machine 1b sets the delay time of the roadside machine 1b and the roadside machines 2a and 3a, and outputs the delay time information to the roadside machines 2a and 3a. The roadside machine 1b adds the delay time set by the roadside machine 1b to the transmission signal and transmits it, and the roadside machines 2a and 3a add the delay time set by the roadside machine 1b to the transmission signal from the own machine. I decided to send it. As a result, the same effects as in the first embodiment can be obtained, and the cost of the system can be reduced by simplifying the configuration of the roadside units of the slave stations excluding the master station among the plurality of roadside units installed. can do.

Embodiment 4 FIG.
This Embodiment demonstrates the case where one roadside machine is provided with a some antenna.

  FIG. 6 is a diagram of a configuration example of a radio communication system according to the fourth embodiment. A road-vehicle communication system in which the roadside devices 6 and 7 and the mobile station 8 perform wireless communication will be described as an example. FIG. 6 shows an example in which the roadside device 6 includes four antennas 31, 32, 33, and 34, and the roadside device 7 includes four antennas 35, 36, 37, and 38. The roadside machines 6 and 7 are installed along the road as shown in FIG. 6 so that directional antennas such as Yagi-Uda antennas or patch antennas are deployed in both directions. The roadside devices 6 and 7 can be operated by setting different delay amounts for the respective antennas.

  In such a wireless communication system, transmission diversity, here, delay diversity can be configured with a larger number of antennas, and the reception quality of the mobile station 8 can be improved. Moreover, in the roadside unit 6, not only the same data can be transmitted in different directions as in the antenna 34 with respect to the antenna 31, but also different data can be transmitted in different directions, so that the frequency can be effectively used. Is possible.

  In FIG. 6, the reference numerals 6 and 7 are given to the portions written as roadside machines in the configuration of the figure, but the roadside machine 6 includes the antennas 31 to 34. 7 includes the antennas 35 to 38.

  It continues and the structure of the roadside machines 6 and 7 is demonstrated. Since the roadside machines 6 and 7 have the same configuration, the roadside machine 6 will be described. FIG. 7 is a block diagram of a configuration example of the roadside machine 6 according to the fourth embodiment.

  In the roadside device 6, the delay time control unit 13, the transmission signal generation unit 14, the delay addition unit 15, and the antenna 16 are deleted from the roadside device 1, and the delay time control unit 13c, the transmission signal generation unit 14c, the delay addition unit 15a, 15b, 15c, 15d and antennas 31-34 are added. The delay time control unit 13 c sets delay times to be added to the four transmission signals based on the position information of the roadside devices 6 and 7 and the position information of the reception point of the mobile station 8. The delay time control unit 13c outputs information on each set delay time to the delay adding units 15a to 15d. The delay adding units 15a to 15d add the delay time set by the extended time control unit 13c to the transmission signal generated by the transmission signal generating unit 14c, and transmit the signals from the antennas 31 to 34 to which the delay signals are connected.

  In addition, the structure of the roadside machine 6 shown in FIG. 7 is an example, Comprising: It does not limit to this. For example, in a roadside machine, one delay adding unit connected to four antennas 31 to 34 copies one transmission signal from the transmission signal generation unit 14 to four, and is set by the delay time control unit 13c. A delay time may be added to each transmission signal and transmitted from the antennas 31 to 34.

  Next, a delay time setting method in the delay time control unit 13c will be described. First, the number of signals received by the mobile station 8 shown in FIG. 6 will be described. In the mobile station 8, two road antennas 6 and 7 arrive from the antennas 31 and 32 on the mobile station 8 side in the roadside machine 6, and antennas 37 and 38 on the mobile station 8 side in the roadside machine 7. A signal shall be received. The mobile station 8 does not receive signals transmitted from the antennas 33 and 34 on the opposite side of the mobile station 8 in the roadside device 6 and the antennas 35 and 36 on the opposite side of the mobile station 8 in the roadside device 7.

  In the mobile station 8, if the signals transmitted from the antennas 31 and 32 of the roadside device 6 are transmitted at the same time, there is almost no difference in the horizontal distance. Can be received at the time. For this reason, the delay time control unit 13c of the roadside device 6 controls the delay time so that the transmission time difference between the antennas 31 and 32 is fixed to an integral multiple of the sampling interval T0. The reception time difference of the signals transmitted from the antennas 31 and 32 at each point can be made the same as the set delay time. The control to the antennas 37 and 38 in the roadside machine 7 is the same.

  Under the control of each delay time control unit 13c of the roadside units 6 and 7, transmission times from the four antennas reaching the mobile station 8 are all set to integer multiples of different sampling intervals T0, that is, different delay times are set for the four antennas. However, the configuration described in Embodiment 1 can be partially used.

  For example, the delay time control unit 13c of the roadside machine 6 performs the same delay time setting control as that of the roadside machine 1 of the first embodiment for the antenna 31, and the delay time control unit 13c of the roadside machine 7 Performs the same delay time setting control as that of the roadside device 2 of the first embodiment. Then, the delay time control unit 13c of the roadside device 6 sets a delay time delayed by the sampling interval T0 from the transmission time of the antenna 31 for the antenna 32, and the delay time control unit 13c of the roadside device 7 sets the antenna time for the antenna 37. A delay time that is delayed by the sampling interval T0 from the 38 transmission times is set.

  Further, it can be virtually considered that the radio communication system shown in FIG. 6 has two radio communication systems shown in FIG. For example, in FIG. 6, the first radio communication system is formed by four antennas 31 and 34 on the lower side of the roadside device 6 and antennas 35 and 38 on the lower side of the roadside device 7, and the antenna 32 on the upper side of the roadside device 6. , 33 and the four antennas 36, 37 on the upper side of the roadside machine 7 constitute a second wireless communication system. In this case, in the first wireless communication system and the second wireless communication system, the delay time may be set assuming different reception points, or the difference in delay time may be set assuming the same reception point. The delay time may be set so as to be a value obtained by multiplying the sampling interval T0 by a different integer. In the former, the performance may be improved at the same time at more reception points. In the latter case, since all roadside devices control delay time assuming a certain reception point, reception quality at the reception point may be further improved.

  In addition, although the roadside units 6 and 7 perform transmission with the two antennas directed in the same direction, the number of antennas is not limited to this. In addition, when only one antenna is directed in one direction, only the same effect as in the first embodiment can be obtained in terms of transmission diversity gain, but gain improvement by directivity control and interference with other roadside devices can be obtained. An avoidance effect is obtained. Further, in the roadside devices 6 and 7, by directing the antennas in two directions, not only the same data in each direction but also different data can be transmitted in different directions from one roadside device. Therefore, the effect of improving the frequency utilization efficiency can be obtained. In FIG. 6, there are two roadside units, but as in the first embodiment, three or more may cooperate to configure transmission diversity.

  As described above, according to the present embodiment, the roadside units 6 and 7 are provided with a plurality of antennas, and transmit a signal with a delay time set for each antenna. Thus, delay diversity can be configured when the same data is transmitted by a plurality of antennas, and effective use of frequency can be achieved when different data is transmitted by a plurality of antennas.

  A hardware configuration for realizing a part of the configuration of the block diagrams of the roadside devices 1, 1a, 1b, 6 and the control station 5 shown in the first to fourth embodiments will be described. FIG. 8 is a diagram illustrating a hardware configuration of each device according to the first to fourth embodiments. In the roadside machine 1, a part of the reception position control unit 12, the delay time control unit 13, the transmission signal generation unit 14, and the delay addition unit 15 is processed by a processor 51 using a RAM (Random Access Memory) and a ROM (Read Only Memory). This is realized by executing a program for each component stored in the memory 52 configured by the above. The roadside machine information storage unit 11 is realized by the memory 52.

  Similarly, the configuration of the roadside devices 1a, 1b, 6 and the control station 5 can also be described with the hardware configuration of FIG. The delay time input unit 17 of the roadside machine 1 a is realized by the processor 51 executing a program for the delay time input unit 17 stored in the memory 52. Further, the delay time control unit 13 b of the roadside machine 1 b is realized by the processor 51 executing a program for the delay time control unit 13 b stored in the memory 52. The transmission signal generator 14 c of the roadside device 6 is realized by the processor 51 executing a program for the transmission signal generator 14 c stored in the memory 52. Further, the delay time control unit 13 c and the delay addition units 15 a to 15 d of the roadside machine 6 are realized by the processor 51 executing the programs for the respective components stored in the memory 52. In addition, each configuration of the roadside machine information storage unit 21, the reception position control unit 22, and the delay time control unit 23 of the control station 5 includes the roadside machine information storage unit 11, the reception position control unit 12, and the delay time control of the roadside machine 1, respectively. The configuration is the same as that of the unit 13.

  The processor 51, the memory 52, and the system bus 53 are connected. In the roadside machine 1 or the like, a plurality of processors 51 and a plurality of memories 52 may cooperate to execute the functions of the components shown in the block diagrams. The roadside machine 1 and the like can be realized by the hardware configuration shown in FIG. 8, but can be implemented by either software or hardware.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  1, 1a, 1b, 2, 2a, 3, 3a, 6, 7 Roadside unit, 4, 8 Mobile station, 5 Control station, 11, 21 Roadside unit information storage unit, 12, 22 Reception position control unit, 13, 13b , 13c, 23 Delay time control unit, 14, 14c Transmission signal generation unit, 15, 15a, 15b, 15c, 15d Delay addition unit, 16, 31, 32, 33, 34, 35, 36, 37, 38 Antenna, 17 Delay time input section.

Claims (8)

A device information storage unit that stores position information of a wireless communication device that performs transmission diversity cooperation;
A reception position control unit that controls position information of a reception point indicating a position of a receiver that receives a transmission signal transmitted from the wireless communication device;
A delay time control unit configured to set a delay time to be added to a transmission signal transmitted from the own device, based on position information of the wireless communication device that performs cooperation of the transmission diversity and position information of the reception point;
A transmission signal generation unit for generating a transmission signal to be transmitted from the own device;
A delay adding unit for adding a delay time set by the delay time control unit to the transmission signal generated by the transmission signal generating unit;
Equipped with a,
The delay time control unit calculates a difference between a reception time of a transmission signal from another wireless communication device and a transmission signal from the own device in the receiver calculated from a distance between each wireless communication device and the reception point. Setting the delay time to be an integral multiple of the sampling interval in the machine,
A wireless communication apparatus. The delay time control unit cooperates with the wireless communication device that performs the cooperation of the transmission diversity, and sets a delay time that becomes a cyclic delay,
The wireless communication apparatus according to claim 1. The reception position control unit assumes different reception points for each transmission opportunity of the transmission signal with respect to the position information of the reception points,
The delay time control unit sets a delay time for each reception point;
The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is a wireless communication apparatus. With multiple antennas,
The delay time control unit sets a different delay time for each antenna.
The wireless communication apparatus according to claim 1, any one of 3, characterized in that. A device information storage unit that stores position information of a wireless communication device that performs transmission diversity cooperation;
A reception position control unit that controls position information of a reception point indicating a position of a receiver that receives a transmission signal transmitted from the wireless communication device;
Each wireless communication device adds to the transmission signal generated by itself for each wireless communication device that performs transmission diversity cooperation, based on the position information of the wireless communication device that performs transmission diversity cooperation and the position information of the reception point. A delay time control unit for setting the delay time;
A transmission signal generation unit for generating a transmission signal to be transmitted from the own device;
A delay adding unit for adding a delay time set by the delay time control unit to the transmission signal generated by the transmission signal generating unit;
Equipped with a,
The delay time control unit calculates a difference between reception times of transmission signals from the wireless communication devices in the receiver calculated from a distance between each wireless communication device and the reception point, and is an integral multiple of a sampling interval in the receiver. Set the delay time to be
A wireless communication apparatus. A device information storage unit that stores position information of a wireless communication device that performs transmission diversity cooperation;
A reception position control unit for controlling position information of a reception point indicating a position at which a receiver receives a transmission signal transmitted from the wireless communication device;
A delay time control unit configured to set a delay time to be added to a transmission signal in each wireless communication device that performs transmission diversity cooperation, based on the position information of the wireless communication device that performs cooperation of transmission diversity and the position information of the reception point; ,
Equipped with a,
The delay time control unit calculates a difference between reception times of transmission signals from the wireless communication devices in the receiver calculated from a distance between each wireless communication device and the reception point, and is an integral multiple of a sampling interval in the receiver. Set the delay time to be
A wireless communication control device. The reception position control unit assumes different reception points for each transmission opportunity of the transmission signal by the wireless communication device with respect to the position information of the reception points,
The delay time control unit sets a delay time for each reception point;
The wireless communication control device according to claim 6 . A plurality of radio communication apparatus according to claim 1, any one of 4, a wireless communication system in which a plurality of wireless communication devices and performing cooperative transmit diversity.

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