Response line allocation method, center station and recording medium

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a response line allocation method, a center station, and a recording medium. For example, when the center station broadcasts data to a large number of user stations via a satellite radio line, whether or not the user station correctly receives the data. It can be used to allocate a wireless line for sending a response signal to the user station to confirm whether or not.

【0002】

[Conventional technology]

For example, when data is broadcast from a center station to a large number of user stations using a satellite wireless line, a communication system as shown in FIG. 9 is used. The wireless line in the direction from the center station to the user station is called a forward line, and the wireless line in the direction from the user station to the center station is called a backward line.

【0003】

In such a system, after distributing information from the center station to multiple user stations via a satellite line, the center station confirms whether each user station has received the information correctly, and the user station that failed to receive the information. If is present, it is necessary to resend the data. As a confirmation method, it is common to make an inquiry from the center station to a plurality of user stations via a satellite line and confirm the response signal sent by the user station at the center station.

【0004】

For such a response, an independent response line may be assigned to each user station, but if an independent response line is assigned, the frequency band occupied or the response time will increase as the number of user stations increases. There is. If there are only two types of response contents to the inquiry, and it is not necessary to grasp the response contents independently for each user station, as if the information was received correctly, the response common to multiple user stations. Lines can be assigned.

【0005】

In this case, it is not necessary for the center station to read the content of the response signal, and the entire response result can be grasped only by identifying the presence or absence of the response signal. In addition, since collision of response signals from multiple user stations can be tolerated, the number of response lines to be prepared for one inquiry is the minimum even when the response signal transmission instructions are given to multiple user stations at the same time. Can be reduced to one.

【0006】

[Problems to be Solved by the Invention]

However, when a common wireless line is assigned to a large number of user stations for transmitting a response signal, if the large number of user stations are in the same situation, the response signals are simultaneously transmitted from the large number of user stations. It will be. For example, if an area is in a rainy state, all user stations in that area are likely to be affected by the same rainfall and fail to receive data, and many user stations in that area respond at the same time. A signal will be sent.

【0007】

Therefore, a large number of response signals will be transmitted intensively at a certain point in time, and when the number of user stations that transmit the response signals at the same time increases, the wireless repeater or receiver on the satellite that receives the response signals The load can be overloaded and the system can be unsafe. When the number of user stations of the data distribution destination is large, a large number of user stations are divided into a plurality of groups in advance, and a response line is assigned to each group to obtain a large number of response signals that may be transmitted. It is possible to disperse and keep the number of response signals received simultaneously by satellites and center stations below the permissible range of the system.

【0008】

However, it is inevitable that the time required for responding to an inquiry will increase by dividing a large number of user stations into a plurality of groups and making inquiries. In addition, since the number of user stations that actually send out the response signal changes depending on the conditions such as the weather, if the number of user stations included in one group is set small, the time required for the response will increase. The number of response signals received may exceed the permissible range at the same time that the number of user stations included in one group is set to a large number.

【0009】

INDUSTRIAL APPLICABILITY In the above-mentioned wireless communication system, the present invention is a response line capable of suppressing an increase in the time required for a response without impairing the safety of the system even when the number of user stations increases. The purpose is to provide an allocation method, a center station, and a recording medium.

【0010】

[Means for solving problems]

The response line allocation method according to claim 1 is, in a wireless communication system composed of a center station and a plurality of user stations, the center station broadcasts an inquiry signal to a plurality of user stations via the wireless line, and the above-mentioned When the center station allocates a common wireless line to a plurality of user stations in order to respond to an inquiry signal from the user station, and there is a correlation among all user stations regarding the content of the response. In addition, the center station selects a part of a plurality of user stations as one group, broadcasts an inquiry signal to the selected plurality of user stations, and makes the inquiry to the plurality of user stations. A common response line is assigned to respond to the signal, and the center station listens for the reception of the response signal transmitted from the user station that matches the content of the inquiry among the user stations included in the selected group, and the center station. The number of user stations included in the group to be selected next by the center station is determined according to the reception result of the response signal in, and the center station determines the determined number of users from the remaining unselected user stations. The station is selected as another group, and the inquiry signal is broadcast to a plurality of user stations included in the selected group, and is common to the plurality of user stations for the response to the inquiry signal. It is characterized by allocating the response line of.

【0011】

In claim 1, it is assumed that there is a correlation among all user stations regarding the content of the response. For example, there is a high correlation between a plurality of user stations existing in the same area in the probability that reception will fail due to the influence of rainfall. Therefore, assuming that only the user stations that have failed to receive the inquiry from the center station transmit the response signal, the correlation of the probability of transmitting the response signal is high among these user stations.

【0012】

Therefore, it is considered that the ratio of the user stations that send a response signal when making an inquiry to a part of the user stations selected from a large number of user stations is almost the same for the remaining user stations that are not selected. Can be done. In claim 1, since the number of user stations in the group to be selected next is determined based on the response result of the user stations of the group selected first, the user stations included in the group selected from the second time onward are determined. It is possible to optimize the number.

【0013】

That is, when the ratio of the user stations that actually send the response signal is very small, a large number of user stations can be included in the group to be selected next, so that the time required for the response can be shortened. If the ratio of user stations that actually send response signals is relatively large, the number of response signals received at the same time can be suppressed within the permissible range by reducing the number of user stations included in the next selected group. However, the safety of the system can be ensured.

【0014】

The first aspect of claim 2 is the first method already transmitted by the center station when the center station sequentially transmits a plurality of inquiry signals having different inquiry contents to the user station in the response line allocation method of claim 1. After the reception result of the response signal from the user station to the inquiry signal of the above is obtained at the center station, the center station performs the second inquiry signal that correlates with the inquiry content of the first inquiry signal regarding the response content of the user station. The feature is that the number of user stations included in one group that gives the second inquiry signal is determined based on the reception result of the response signal from the user station to the first inquiry signal. To do.

【0015】

In claim 2, it is assumed that the center station sequentially sends a plurality of inquiry signals having different inquiry contents to the user station. For example, when a plurality of data blocks are sequentially distributed from a center station to a user station, assuming that the reception result is inquired by inquiry signals independent of each other for each data block, the same user station is the response signal. There is a large correlation between multiple query signals in terms of the probability of sending.

【0016】

When there is such a correlation, the number of user stations included in the next inquiry target group is determined by using the reception result of the response signal related to another inquiry signal. Can be optimized. In addition, when the reception result of the response signal for another inquiry signal is obtained, the number of user stations can be optimized for the group selected first, so that the number of inquiries can be reduced and the time required for the response can be further shortened. can do.

【0017】

According to claim 3, in the response line allocation method of claim 1 or 2, the center station detects a response signal transmitted from at least one user station with respect to one inquiry signal transmitted by the center station. In this case, the transmission of the same inquiry signal to the unselected user station is omitted. Assuming that the center station detects at least one response signal and the data is retransmitted by broadcast transmission, the case where the response signal from the user station is detected for one of the multiple divided groups and the case where the multiple groups are detected. There is no change in the retransmission operation of the center station when the response signal from each user station is detected.

【0018】

Therefore, in claim 3, when the center station detects a response signal transmitted from at least one user station, transmission of the same inquiry signal to the unselected user station is omitted. As a result, the number of inquiries can be reduced and the time required for the response can be further shortened.

【0019】

A fourth aspect of the present invention is the response line allocation method of the first aspect, wherein each inquiry signal transmitted by the center station includes destination information that identifies the destination user station or a group of the user stations. By including the destination information in the inquiry signal, each user station can identify whether or not the received inquiry signal is addressed to its own station, so that it is possible to prevent user stations other than the destination from sending a response signal. it can.

【0020】

The center station of claim 5 is a center station that communicates with a plurality of user stations via a wireless line, and is a broadcast distribution means that broadcasts an inquiry signal to a plurality of user stations via the wireless line. And the response line allocating means for allocating a common wireless line to a plurality of user stations for the response from the user station to the inquiry signal, and the user station that has given the inquiry signal and that matches the content of the inquiry. The response signal receiving means for receiving the response signal to be received and grasping the state of the user station, the first group selecting means for selecting a plurality of user stations as one group as the destination of the inquiry signal, and the above. The number of user stations determined according to the reception result of the response signal from the user stations included in the group selected by the first group selection means is selected as another group from the unselected user stations. It is characterized by providing a second group selection means.

【0021】

In claim 5, as in claim 1, it is assumed that there is a correlation among all user stations regarding the content of the response. By configuring the communication system using the center station of claim 5, the response line allocation method of claim 1 can be implemented. A sixth aspect of the present invention is a response signal from the user station to the first inquiry signal already transmitted when the center station of the fifth aspect sequentially transmits a plurality of inquiry signals having different inquiry contents to the user station. After the reception result of is obtained, the inquiry correlation identification means for identifying the correlation between the inquiry content of the second inquiry signal to be transmitted next and the inquiry content of the first inquiry signal with respect to the response content of the user station. , When the query correlation identification means sends out the second query signal that has recognized the correlation, a second query signal is given based on the reception result of the response signal from the user station to the first query signal. It is characterized by further providing a query correlation identification means for determining the number of user stations included in one group.

【0022】

In claim 6, as in claim 2, it is assumed that the center station sequentially sends out a plurality of inquiry signals having different inquiry contents to the user station. By configuring the communication system using the center station of claim 6, the response line allocation method of claim 2 can be implemented. A seventh aspect of the present invention is the unselected user station when the center station of the fifth or sixth aspect detects a response signal transmitted from at least one user station for one transmitted inquiry signal. It is characterized by further providing a transmission omission means for omitting transmission of the same inquiry signal to.

【0023】

By configuring the communication system using the center station of claim 7, the response line allocation method of claim 3 can be implemented. The recording medium of claim 8 is a recording medium on which a computer-readable program for controlling a center station that communicates with a plurality of user stations via a wireless line is recorded, and the program is wirelessly recorded. A procedure for broadcasting an inquiry signal from a center station to a plurality of user stations via a line, a procedure for allocating a common wireless line to a plurality of user stations for a response from the user station to the inquiry signal, and a procedure for allocating a common wireless line to the plurality of user stations. A procedure for receiving a response signal transmitted from a user station that matches the content of the inquiry among the user stations to which the inquiry signal is given and identifying the state of the user station at the center station, and a plurality of parts as destinations of the inquiry signal. After the procedure for selecting the user stations of the above as one group and the reception result of the response signal from the user stations included in the selected group are obtained, the number of user stations determined according to the reception result is selected. , It is characterized by providing a procedure for selecting as another group from unselected user stations.

【0024】

In claim 8, as in claim 1, it is assumed that there is a correlation among all user stations regarding the content of the response. The response line allocation method of claim 1 can be implemented by reading and executing the program recorded on the recording medium of claim 8 by the computer of the center station. A ninth aspect of the present invention is the recording medium of the eighth aspect, wherein when a plurality of inquiry signals having different inquiry contents are sequentially transmitted to the user station, the user with respect to the first inquiry signal already transmitted. After the reception result of the response signal from the station is obtained, the correlation between the inquiry content of the second inquiry signal to be transmitted next and the inquiry content of the first inquiry signal is identified with respect to the response content of the user station. One group that gives a second query signal based on the reception result of the response signal from the user station to the first query signal when sending the second query signal that recognizes the procedure and the correlation. It is characterized by further providing a procedure for determining the number of user stations included.

【0025】

In claim 9, as in claim 2, it is assumed that the center station sequentially sends a plurality of inquiry signals having different inquiry contents to the user station. The response line allocation method of claim 2 can be implemented by reading and executing the program recorded on the recording medium of claim 9 by the computer of the center station. A tenth aspect of the present invention is the recording medium of the eighth or ninth aspect, when the program detects a response signal transmitted from at least one user station for one transmitted inquiry signal. It is characterized by further providing a procedure for omitting the transmission of the same inquiry signal to an unselected user station.

【0026】

The response line allocation method of claim 3 can be implemented by reading and executing the program recorded on the recording medium of claim 10 by the computer of the center station.

【0027】

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) The response line allocation method of the present invention and one embodiment of a center station and a recording medium will be described with reference to FIGS. 1, 2, 4, 5, and 8. This form corresponds to claim 1, claim 2, claim 4 to claim 6, claim 8 and claim 9.

【0028】

FIG. 1 is a flowchart showing the operation of the center station regarding the inquiry of the center station of this form. FIG. 2 is a block diagram showing the configuration of a center station of this form. FIG. 4 is a sequence diagram showing a communication sequence (1) between the center station and the user station. FIG. 5 is a sequence diagram showing a communication sequence (2) between the center station and the user station. FIG. 8 is a block diagram showing an operation example of this type of system.

【0029】

In this embodiment, the broadcast distribution means, the response line allocating means, the response signal receiving means, the first group selection means and the second group selection means according to claim 5 are described in steps S12, S13, S14, S11 and S16, respectively. Correspond. Further, the query correlation identification means and the query correlation identification means of claim 6 correspond to steps S20 and S21, respectively.

【0030】

In this embodiment, it is assumed that the present invention is applied to a communication system as shown in FIGS. 8 and 9. That is, the center station broadcasts data to a plurality of user stations via a satellite wireless line. Further, in order for the center station to confirm whether or not the distributed data has been correctly received by the user station, the center station broadcasts a non-delivery response request signal, which is a kind of inquiry signal, to a plurality of user stations.

【0031】

The user station sends a non-delivery response signal to the non-delivery response request signal only when the data reception fails. The center station listens for the response signal from the user station after sending the non-delivery response request signal, and grasps the state of the user station depending on the presence or absence of the response signal. Further, in this example, the non-delivery response request signal sent by the center station includes at least one user ID of the user station indicating the destination. Each user station recognizes it as an inquiry to its own station only when the received non-delivery response request signal contains destination information that matches the user ID of its own station. That is, the user station does not send a response signal to the non-delivery response request signal that is not addressed to the own station.

【0032】

When a non-delivery response request signal addressed to a plurality of user stations is sent from the center station, a common response wireless line is secured for the plurality of destination user stations. Therefore, when a non-delivery response request signal addressed to a large number of user stations is transmitted, a large number of user stations may transmit a response signal to the same wireless line at the same time, and the concentration of the response signals is allowed by the system. It may exceed the range.

【0033】

In this embodiment, the control of the center station is controlled so that the concentration of the response signal does not exceed the allowable range of the system. As shown in FIG. 2, the center station has a satellite line receiving unit 11, a response signal detecting unit 12, a response signal analysis unit 13, a data analysis unit 14, an inquiry signal generating unit 15, a satellite line transmitting unit 16, and a content data storage unit 17. It is equipped with a user station information management unit 18, antennas 19 and 20.

【0034】

The satellite line receiving unit 11 receives the response signal from the user station transmitted via the satellite line. In addition, the satellite line transmission unit 16 transmits data and inquiry signals to be distributed to the user station via the satellite line. The response signal detection unit 12 detects the number of response signals from the user station received by the satellite line reception unit 11. The presence or absence of a response signal is identified by the presence or absence of a carrier of the response signal. It is also possible to identify the number of user stations that have sent a response signal by monitoring the received power value of the response signal.

【0035】

The response signal analysis unit 13 grasps the result of each inquiry based on the signal output by the response signal detection unit 12. The user station information management unit 18 manages information such as a user ID of each user station. Further, the user station information management unit 18 uses the result of the inquiry grasped by the response signal analysis unit 13 to determine a plurality of user stations included in each group to which a common response line is assigned at the same time.

【0036】

The inquiry signal generation unit 15 generates an inquiry signal addressed to the user station. This query signal contains one or more user IDs. The content data storage unit 17 stores data of various contents that can be distributed to the user station. The data analysis unit 14 determines whether or not to transmit the inquiry signal and whether or not to transmit the data.

【0037】

The specific operation regarding the inquiry of the center station is shown in Fig. 1. The functions of the center station shown in FIGS. 1 and 2 can be configured by dedicated hardware, or can be configured by a program and a computer that executes the program. When using a program, the program may be recorded on a recording medium such as a CD-ROM, read from this recording medium into a computer, and executed.

【0038】

In this form, since it is assumed that a satellite line is used for data distribution, there is a possibility that reception failure may occur in the user station due to the influence of rainfall. In addition, when there are many user stations in the area where rainfall has occurred, many user stations simultaneously send out non-delivery response signals, so the concentration of non-delivery response signals puts a load on the center station and wireless line relay device. It becomes a problem.

【0039】

Since there is a low probability that multiple user stations existing in the same area will fail to receive data at the same time except for the effects of rainfall, when distributing data only to user stations existing in the same area, data reception of all user stations It is considered that the possibility of this occurs almost at the same time depending on the rainfall situation. Therefore, in this form, even if all users in the selected group send a non-delivery response signal, the same response line is first provided to a number of user stations in a range in which the concentration of the non-delivery response signal does not exceed the permissible range of the system. The rainfall situation in the data distribution area is predicted based on the allocation and the response results from those user stations, and the number of user stations in the group to which the response line is allocated next is determined based on the result.

【0040】

That is, in a situation where the ratio of user stations that send non-delivery response signals is low, the number of user stations that allocate the same response line should be as large as possible within the range where the concentration of non-delivery response signals does not exceed the permissible range of the system. Change to. By repeating such response line allocation, the concentration of non-delivery response signals is avoided, and the number of response line allocations required for the response of all user stations is reduced to shorten the response time.

【0041】

The operation of the center station shown in FIG. 1 will be described below. In step S11, K predetermined user stations are selected as one group from all the user stations. Here, as all user stations, a large number of user stations for data distribution existing in the same area are assumed. Therefore, the probabilities that these user stations simultaneously send out non-delivery response signals are approximately equal. Further, the constant K is determined so that the safety of the system is not impaired even if K user stations simultaneously send out response signals.

【0042】

In step S12, the inquiry signal is simultaneously distributed to all the user stations included in the selected one group. Initially, the inquiry signal is delivered to K user stations. In step S13, a common response line is assigned to all the user stations that delivered the inquiry signal in step S12.

【0043】

In step S14, the response signal from the user station is awaited at the time when the response signal may reach the center station, and the presence / absence of the response signal and the number of received response signals received at the same time are identified. In step S15, it is identified whether or not all the user stations in the same area to which the data should be distributed have already been selected as the user stations included in the group. If unselected user stations remain, the process proceeds to step S16, and if all user stations have already been selected, the process proceeds to step S18.

【0044】

In step S16, the number N of user stations in the next group is determined according to the detection result of the response signal in step S14. If step S14 has already been executed a plurality of times, the number of user stations N can be determined so as to reflect the result of detecting the response signals a plurality of times. In step S17, N user stations determined in step S16 are selected as one group from the unselected user stations.

【0045】

Therefore, when the number of user stations for data distribution is large, the processes of steps S12, S13, S14, S15, S16, S17, S12, ... Are repeated, and a large number of user stations are sequentially arranged for each group. Answer lines are sequentially assigned to the selected user stations. In step S18, processing such as data retransmission is executed according to the detection result of the response signal in step S14.

【0046】

In this form, it is assumed that a plurality of data are sequentially distributed from the center station to the user station, and independent inquiry signals are sequentially transmitted for each of the distributed data. In step S19, it is identified whether or not all the inquiry signals corresponding to all the distributed data have been transmitted. If there is data for which the inquiry has not been completed, the process proceeds to step S20, and if the inquiry for all the data is completed, this process ends.

【0047】

In step S20, the correlation between the inquiry content of the inquiry signal previously transmitted and the inquiry content of the inquiry signal to be transmitted next regarding the response of the user station is identified. For example, when a plurality of data blocks are sequentially distributed and the center station sends an inquiry signal for each data block, the user station sends a non-delivery response signal to the inquiry signal corresponding to one data block. Since it is considered that the probability of sending and the probability of the user station sending a non-delivery response signal to the query signal corresponding to another data block are considered to be almost the same, there is a large correlation between the two.

【0048】

If the correlation is high, the process proceeds from step S20 to S21, and if the correlation is low, the process proceeds to step S12. In step S21, the number N of user stations of the group to be selected next is determined according to the response signal detection result in step S14 for the previously transmitted inquiry signal. The next group to be selected is the first group, but the probability that the user station of that group will send a response signal is highly correlated with the response signal detection result of the inquiry made earlier, so it was obtained earlier. By using the response signal detection result, it is possible to determine an appropriate number of user stations N.

【0049】

In step S22, one group of user stations is selected from all user stations as in step S11. However, the number of user stations selected in step S22 is N determined in step S21. In this form, the response line is assigned to each user station, for example, as shown in FIG. In the example of FIG. 8, since the non-delivery response request signal is broadcasted from the center station to all the user stations, the signal transmitted to one forward line is received by all the user stations. In addition, a user ID representing the destination user station is added to the non-delivery response request signal. A common response line is assigned only to user stations that have a user ID that matches the destination user ID.

【0050】

Among the user stations to which the response line is assigned, the user station to which the corresponding data cannot be received correctly and correctly transmits the non-delivery response signal via the response line. By monitoring the power value of the non-delivery response signal transmitted via the response line, the center station can detect the presence or absence of the non-delivery response signal or the number thereof. In the example of FIG. 8, it is assumed that a response line for the inquiry is assigned by transmitting a non-delivery response request signal for the data transmitted by the center station. The "" and "×" in the reception result indicate whether or not the data was correctly received.

【0051】

That is, the user station (1) and the user station (4) have failed to receive data. Moreover, since the user IDs of the user station (1) and the user station (2) are added to the non-delivery response request signal, the common response line is assigned only to the user station (1) and the user station (2). ing. Therefore, the user station (3) and the user station (4) do not send a non-delivery response signal. Further, the user station (1) sends a non-delivery response signal on the assigned response line, and the user station (2) does not send a non-delivery response signal because the data reception is successful. By detecting the response signal, the center station knows that either the user station (1) or the user station (2) has failed to receive data.

【0052】

An example of a specific communication sequence will be described with reference to FIG. In this example, it is assumed that the total number of user stations existing in the same area to be data distribution is 500, and the number of simultaneous transmission signals of the center station or satellite repeater allowed by the system is 10. It also represents the case where there is no rainfall in the area where all user stations exist.

【0053】

Further, in the example of FIG. 4, only one wireless line having the same frequency is used as the response line, and different time zones are sequentially assigned to the user stations of different groups as independent response lines of each group. .. The center station first broadcasts the data to all user stations. Immediately after that, in order to confirm whether or not the reception of the delivered data (Data) has failed, the transmission of the non-delivery response request signal "NPOL" which is the inquiry signal corresponding to the data (Data) is started.

【0054】

In the example of FIG. 4, the non-delivery response request signal "NPOL (Gr1)" destined for the group (1), the non-delivery response request signal "NPOL (Gr2)" destined for the group (2), and the group ( The non-delivery response request signal "NPOL (Gr3)" destined for 3) is sequentially transmitted from the center station. In addition, only one user station included in group (2) fails to receive data (Data), and one wave of non-delivery response signal "NACK" is sent to the non-delivery response request signal "NPOL (Gr2)". Sending.

【0055】

In this example, the system allows 10 simultaneous transmission signals, so the center station includes 10 user stations in the first group (1) selected for inquiry. That is, the constant K used in step S11 in FIG. 1 is set to 10. As a result, even in the worst reception situation, the number of user stations that simultaneously transmit the non-delivery response request signal can be suppressed to 10 or less, so that the safety of the system can be ensured.

【0056】

In the example of FIG. 4, since the response signal for the non-delivery response request signal "NPOL (Gr1)" is not sent from the user station selected as the group (1), the next group after the standby time of W (Gr1) has elapsed. Select. In this example, since the non-delivery response signal "NACK" from the group (1) is not detected, the center station can recognize that no rainfall has occurred in the area where the user station exists. Therefore, based on the response result, the number of user stations N to be selected as the group (2) is determined to be 100.

【0057】

That is, a non-delivery response request signal "NPOL (Gr2)" including 100 user stations of group (2) as destinations is transmitted from the center station. For this non-delivery response request signal "NPOL (Gr2)", a one-wave non-delivery response signal "NACK" is detected at the center station. In this example, since the number of user stations that failed to receive is only one out of 100 stations, the center station can recognize that the cause of the reception failure is not the effect of precipitation. Therefore, the number N of user stations in the next group (3) is determined to be the same as the number of remaining user stations 390.

【0058】

That is, since the number of user stations that failed to receive is only one out of 100 stations, assuming that the user stations in group (3) fail to receive with the same probability, 390 stations even if the margin is taken into consideration. The number of user stations that fail to receive does not exceed 10. Therefore, in the example of FIG. 4, the reception status of all user stations can be confirmed only by making inquiries in three steps. If 10 user stations are selected based only on the number of simultaneous transmission signals (10) allowed by the system, the inquiry will be made in (500/10 = 50) times, so by the time the inquiry is completed. It takes a long time.

【0059】

In this way, by determining the number of user stations (N) to be selected in the next inquiry using the reception result of the response signal already obtained, the actual non-delivery is achieved as in the case where the corresponding area is not in a rainfall state. When the ratio of user stations that send the response signal "NACK" is small, the number of inquiries and response line allocations can be reduced, and the time required for inquiries can be shortened.

【0060】

If the ratio of user stations that send the non-delivery response signal "NACK" is small, the center station identifies the user station that failed to receive by including the information of the user station ID of the transmission source in the signal. It is also possible. Another example of a specific communication sequence will be described with reference to FIG. In this example, it is assumed that the total number of user stations existing in the same area to be data distribution is 500, and the number of simultaneous transmission signals of the center station or satellite repeater allowed by the system is 10. It also represents the case where there is no rainfall in the area where all user stations exist.

【0061】

Since it is unlikely that user stations in the same area will fail to receive data at the same time except due to the effects of rainfall, whether or not all user stations can receive data will occur almost at the same time depending on the rainfall situation, and the situation will change in a short time. It is unlikely that it will change suddenly. Therefore, as shown in FIG. 5, when a plurality of data Data (1) and Data (2) are sequentially transmitted at relatively short time intervals, the response probability and data of the user station to the inquiry of the data Data (1). Consider that there is a high correlation with the response probability of the user station to the inquiry of Data (2).

【0062】

That is, even if the response result of the user station for the inquiry signal of the same data does not yet exist, if the response result of the user station for the inquiry signal of other data exists, the response result is used 1 Determine the number of user stations N to be included in the group (S21 in Fig. 1). In the example of FIG. 5, only one wireless line having the same frequency is used as the response line, and different time zones are sequentially assigned to the user stations of different groups as independent response lines of each group.

【0063】

In addition, the non-delivery response request signals "NPOL (D1, Gr1)", "NPOL (D1, Gr2)", and "NPOL (D1, Gr3)" are groups (1), (2) as inquiries to the data Data (1). , (3) are sent to the user stations in sequence, and the non-delivery response request signals "NPOL (D2, Gr4)" and "NPOL (D2, Gr5)" are grouped (4) as inquiries to the data Data (2). , (5) are sequentially sent to the user station. As in the case of FIG. 4, the number of user stations selected in the groups (1), (2) and (3) is 10, 100 and 390, respectively.

【0064】

In the example of FIG. 5, only one user station sends a non-delivery response signal "NACK" to the non-delivery response request signal "NPOL (D1, Gr2)" corresponding to the data Data (1), and the data Data ( Neither user station sends a response signal to the non-delivery response request signals "NPOL (D2, Gr4)" and "NPOL (D2, Gr5)" corresponding to 1). In this example, the non-delivery response request signal "NPOL (D1, Gr3)" that has already been obtained when determining the number of user stations (N) in the first group (4) regarding the inquiry of the reception result of the data Data (2) ) , And use the response result.

【0065】

That is, since there is no user station in the group (3) that failed to receive the data Data (1), there is not enough rainfall in the corresponding area to fail to receive the data. Can be recognized. Therefore, when selecting the first group (4) for the data Data (2), the number of user stations (N) is determined to be 100.

【0066】

In addition, when determining the number of user stations (N) of the second group (5) regarding the inquiry of the reception result of the data Data (2), the response result of the group (4) to the data Data (2) is used. .. That is, since there is no user station in the group (4) that failed to receive the data Data (2), there is not enough rainfall in the corresponding area to fail to receive the data. Can be recognized. Therefore, when selecting the group (5) for the data Data (2), the number of user stations (N) is determined to be 400. That is, all the remaining user stations are assigned to group (4).

【0067】

With such control, as shown in FIG. 5, it is possible to grasp the reception status of all user stations for the two data Data (1) and Data (2) only by dividing into five inquiries. Moreover, there is no concern that the safety of the system will be impaired. (Second Embodiment) The response line allocation method of the present invention and one embodiment of the center station and the recording medium will be described with reference to FIGS. 3, 6, and 7. This form corresponds to claim 3, claim 7 and claim 10.

【0068】

FIG. 3 is a flowchart showing the operation of the center station regarding the inquiry of the center station of this form. FIG. 6 is a sequence diagram showing a communication sequence (3) between the center station and the user station. FIG. 7 is a sequence diagram showing a communication sequence (4) between the center station and the user station. In this form, the delivery omitting means of claim 7 corresponds to step S31. This form is a modification of the first embodiment. The system configuration, center station configuration, user station environment, etc. are the same as those in the first embodiment. Further, in FIG. 3, the steps corresponding to those in FIG. 1 are given the same step numbers. The following description will be omitted for the same parts.

【0069】

In this form, if there is even one user station that failed to receive the data sent from the center station, it is assumed that the center station retransmits the data regardless of the number of failed user stations. doing. Further, since it is assumed that a satellite line is used for data distribution, reception failure may occur due to the influence of rainfall as in the first embodiment.

【0070】

Since it is unlikely that user stations existing in the same area will fail to receive data at the same time except for the effects of rainfall, whether or not all user stations can receive data will occur almost at the same time depending on the rainfall situation, and the situation will be short. It is unlikely that it will change suddenly. In addition, the data retransmitted from the center station by broadcast distribution can be received simultaneously by all the user stations that failed to receive, so when a non-delivery response signal from any one user station is detected. Can decide to resend the data at that time. That is, by resending data to all user stations without making inquiries to unconfirmed user stations, it is possible to deal with the situation of all user stations that have failed to receive data.

【0071】

Therefore, in this embodiment, a new step S31 is added between steps S14 and S15 as shown in FIG. In this step S31, it is identified whether or not the response signal (non-delivery response signal) from at least one user station is detected in step S14. If no response signal is detected, the process proceeds from step S31 to S15, and if a response signal is detected, the process proceeds from steps S31 to S18.

【0072】

That is, even if there are still user stations that have not been assigned inquiry and response lines, if the center station detects response signals from one or more user stations, further inquiry and response lines will be available. Is omitted, and data is retransmitted to all user stations. Further, instead of step S16 in FIG. 1, step S32 is provided in FIG. In this step S32, when the response signal detection result has already been obtained a plurality of times, not only the immediately preceding response signal detection result but also the multiple response signal detection results detected so far are comprehensively determined. Then, the number of user stations N to be included in the next group is determined. Other processes are the same as those in the first embodiment.

【0073】

An example of a specific communication sequence will be described with reference to FIG. In this example, it is assumed that the total number of user stations existing in the same area to be data distribution is 500, and the number of simultaneous transmission signals of the center station or satellite repeater allowed by the system is 10. It also represents the case where there is no rainfall in the area where all user stations exist.

【0074】

Further, in the example of FIG. 6, only one wireless line having the same frequency is used as the response line, and different time zones are sequentially assigned to the user stations of different groups as independent response lines of each group. .. The center station first broadcasts the data to all user stations. Immediately after that, in order to confirm whether or not the reception of the delivered data (Data) has failed, the transmission of the non-delivery response request signal "NPOL" which is the inquiry signal corresponding to the data (Data) is started.

【0075】

In this example, a non-delivery response signal "NACK" is sent from a user station included in the first selected group (1) in response to the non-delivery response request signal "NPOL" related to data. ing. In addition, since the number of simultaneous transmission signals allowed by the system is 10, the center station cannot be simultaneously transmitted from the user station even in the worst situation where all the user stations to which the response line is assigned simultaneously transmit the response signal. The number of user stations (K) to be included in the first group (1) is set to 10 so that the number of arrival response request signals "NPOL" does not exceed the permissible number 10.

【0076】

As shown in FIG. 6, in this example, at least one user station of the group (1) does not reach the non-delivery response request signal "NPOL (Gr1)" for the user stations (10 stations) of the group (1). The response signal "NACK" is sent and the center station detects it.

【0077】

In this case, when making an inquiry to the user stations (10 stations) of the group (1), the process proceeds from steps S31 to S18 in FIG. 3, so that the inquiry to the remaining 490 user stations and the allocation of the response line are omitted, immediately after that. Move to data retransmission. As a result, inquiries to all user stations can be completed only by making inquiries to one group and assigning a response line. Therefore, the number of inquiries and the required time can be further reduced as compared with the first embodiment.

【0078】

Another example of a specific communication sequence will be described with reference to FIG. In this example, it is assumed that the total number of user stations existing in the same area to be data distribution is 500, and the number of simultaneous transmission signals of the center station or satellite repeater allowed by the system is 10. It also represents the case where there is no rainfall in the area where all user stations exist.

【0079】

Further, in the example of FIG. 7, a case is shown in which a plurality of data Data (1) and Data (2) are sequentially transmitted at relatively short time intervals. In this case, considering that the response probability of the user station to the inquiry of data Data (1) and the response probability of the user station to the inquiry of data Data (2) are highly correlated, the user station responds to the inquiry signal of the same data. Even if the response result does not exist yet, if the response result of the user station to the query signal of other data exists, the response result is used to determine the number N of user stations to be included in one group. Can be done (S21 in Fig. 3).

【0080】

In the example of FIG. 7, the non-delivery response request signal "NPOL (D1, Gr2)" addressed to the second group (2) regarding the data Data (1) is not received from the user station included in the group (2). Indicates a case where the arrival response signal "NACK" is sent and no user station sends the non-delivery response signal "NACK" to the non-delivery response request signal "NPOL (D2)" related to the data Data (2). There is.

【0081】

In addition, since the number of simultaneous transmission signals allowed by the system is 10, the center station cannot be simultaneously transmitted from the user station even in the worst situation where all the user stations to which the response line is assigned simultaneously transmit the response signal. The number of user stations (K) to be included in the first group (1) is set to 10 so that the number of arrival response request signals "NPOL" does not exceed the permissible number 10.

【0082】

In this example, when determining the number N of user stations in the second group (2), the non-delivery response signal "NACK" is the center station for the non-delivery response request signal "NPOL (D1, Gr1)". Determined to (N = 100) considering that it was not detected. Also, for the non-delivery response request signal "NPOL (D1, Gr2)" addressed to the second group (2), the non-delivery response signal "NACK" is detected at the center station, so at this point the center station Then, recognizing that there is one or more user stations that failed to receive, the transmission of the non-delivery response request signal "NPOL" to the remaining user stations (500-10-100 = 390) is omitted, and the next data Data Move to the inquiry about (2).

【0083】

When determining the number of user stations N of the first group (3) regarding the inquiry of data Data (2), the non-delivery response request signal "NPOL (NPOL)" addressed to the second group (2) of data Data (1). Considering the fact that the number of non-delivery response signals "NACK" detected by the center station for "D1, Gr2)" was only one wave, the center station rained the detected non-delivery response signal "NACK". It is judged that the reception has failed due to the influence of the above, and it is judged that the rainfall has not occurred to the extent that the data reception fails in the distribution area. Then, the number of user stations (N) of the group (3) to be selected first is determined to be 100.

【0084】

Regarding the non-delivery response request signal "NPOL (D2, Gr3)" for the user stations of group (3), the non-delivery response signal "NACK" is not detected at the center station, so the number of user stations of the next group (4) ( When determining N), all the remaining user stations are assigned to group (4) in consideration of the response signal detection results so far. That is, the number of user stations in group (4) is determined to be 400.

【0085】

Therefore, in the example of FIG. 7, all the inquiries of the two data Data (1) and Data (2) are completed with only four inquiries to the four groups. Further, in this example, the data Data (1) is retransmitted after the inquiry is completed. Comparing the example of FIG. 7 with the example of FIG. 5, it can be seen that the number of inquiries and the required time are further reduced.

【0086】

In this way, when the non-delivery response signal "NACK" is detected, the subsequent allocation of the response line is omitted, so that the number of times the response line is allocated in a situation where many user stations transmit the non-delivery response signal "NACK". Can be reduced. In addition, by increasing the number of user stations (N) that allocate the same response line when the response signal is not detected, the number of allocations of the response line can be increased even when there are few user stations that send the non-delivery response signal "NACK". Can be reduced.

【0087】

[Effect of the invention]

According to the present invention, when there is a correlation among all user stations regarding the content of the response, the number of user stations to which the response line is allocated at the same time is adaptively determined by using the already detected response result. When the number of simultaneous transmission signals in the center station or wireless repeater is limited and it is necessary to avoid the concentration of response signals, the safety of the system can be ensured and the number of inquiries and the required time can be reduced.

【0088】

Further, when the response signal to the inquiry is detected, the number of inquiries and the required time can be further reduced by omitting the inquiry to the unselected user station and the allocation of the response line.

[Simple explanation of drawings]

[Figure 1]

It is a flowchart which shows the operation of the center station about the inquiry of the center station of 1st Embodiment.

[Figure 2]

It is a block diagram which shows the structure of the center station of 1st Embodiment.

[Fig. 3]

It is a flowchart which shows the operation of the center station about the inquiry of the center station of the 2nd Embodiment.

[Fig. 4]

It is a sequence diagram which shows the communication sequence (1) between a center station and a user station.

[Fig. 5]

It is a sequence diagram which shows the communication sequence (2) between a center station and a user station.

[Fig. 6]

It is a sequence diagram which shows the communication sequence (3) between a center station and a user station.

[Fig. 7]

It is a sequence diagram which shows the communication sequence (4) between a center station and a user station.

[Fig. 8]

It is a block diagram which shows the operation example of the system of embodiment.

[Fig. 9]

It is a block diagram which shows the configuration example of the communication system.

[Explanation of symbols]

11 Satellite line receiver 12 Response signal detector 13 Response signal analysis unit 14 Data analysis department 15 Inquiry signal generator 16 Satellite line transmitter 17 Content data storage section 18 User Station Information Management Department 19,20 antenna