JPH0373624A - Line controlling method - Google Patents

Abstract

PURPOSE:To obtain a high transmission efficiency by allowing each slave station to use a slot reservation part in an optional sub frame in a TDMA frame on an in-bound line to apply a time slot assignment request in a communication system where a master station and plural slave stations use an in-bound line and an out-bound line. CONSTITUTION:A signal on an in-bound line 5 consists of TDMA frame units and one TDMA frame 50 consists of plural sub frames 51. Each sub frame consists of a reservation part 52 and a slot part 53 including at least one time slot. A slave station having transmission information uses an optional slot reservation part 52 to apply reservation request of the time slot when no assignment of a slot to its own station by a line control burst 63 of an out-bound line 6 or a new time slot is required in addition to the assigned slot and a master station receiving the reservation request revises part of the time slot assignment informed by the line control burst 83 in response to the reservation and informs the result to all slave stations by using a slot assignment revision burst 64.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a single-line control method, and particularly to communication in which a master station and a plurality of slave stations communicate with each other with high transmission efficiency using time-division frames. This invention relates to a line control method suitable for the system.

[Conventional technology]

In the conventional line control method, first, the master station writes time slot assignment information to each slave station in the next frame in the header part of a fixed-length frame, and each slave station performs the time slot assignment according to that information. I was trying to fill in information for each time slot given.

Furthermore, the header section of the above frame includes a reservation section for each slave station to request a time slot, and the slave station requesting time slot allocation uses the reservation section to reserve the next frame. Time slots were assigned to the master station in the header.

As mentioned above, there is one example of a method in which the master station uses the header part of a fixed-length frame to allocate time slots for the next frame.

This method is disclosed in ``Time slot allocation method for multi-channel frames'' in Japanese Patent Application Laid-Open No. 61-171243.

[Problem to be solved by the invention]

In the conventional technology described above, when each slave station requests a new time slot, it is possible to actually secure the time slot even if the request is made using the reservation section in the header of the frame. Until now, there was a problem in that the transmission efficiency of the entire system was lowered because at least two frame times had elapsed.

For example, in a broadcast communication system in which a master station broadcasts broadcast information to multiple slave stations, and each slave station sends back response information, each slave station may receive broadcast information from the master station due to an error in receiving the broadcast information. In many cases, a request for retransmission of the broadcast information is made.

In that case, each slave station first requests a time slot for requesting retransmission, and uses the time slot obtained as a result to request retransmission. However, in the conventional line control method described above,
In other words, you have to wait for a time slot allocation request for a period of about 1/2 of the average frame length until the reserved part in the header of the frame arrives, and even if you request a time slot using the reserved part, the actual had to wait at least two frames long before using that time slot. Therefore, especially in a system with a large number of slave stations, it takes a long time to recover from an error by retransmission.

Another problem arises when the transmission efficiency of the entire system decreases. Furthermore, if the frame length used in the system is relatively long (for example, 2 seconds), the reduction in transmission efficiency becomes noticeable.

An object of the present invention is to provide a line control method that achieves high transmission efficiency in a broadcast communication system in which a master station and a plurality of slave stations communicate with each other using inbound lines and outbound lines with different frequencies. In particular, it is an object of the present invention to provide a line control method that can obtain high transmission efficiency even when the time division frames used by a master station and a plurality of slave stations are relatively long.

[Means to solve the problem]

In order to achieve the above object, in the line control method of the present invention, a TDMA frame on an inbound line used for transmitting information from each slave station to a master station is composed of a plurality of subframes, Each subframe includes a slot reservation part for requesting the master station to allocate a time slot and at least one time slot, and each slave station has one time slot.
1°l) A slot reservation section of any subframe within the MAA frame is used to request allocation of a time slot within the 'I' DMA frame.

In addition, the master station that receives a time slot allocation request from a slave station transmits a signal to each slave station using an outband line to change the time slot assignment within the TDMA frame. In this case, the master station uses an outband circuit to transmit a signal for changing the time slot assignment to the slave station that has requested time slot assignment before the newly assigned time slot.

For example, when each slave station returns response information (response packet) indicating whether or not a reception error has occurred to the master station in response to broadcast information broadcast from the master station, the master station sends a TDMA frame. In a communication system in which each time slot in the frame is assigned to each slave station using the control unit of the frame, and each slave station writes response information in each assigned time slot, the slave station in which a reception error occurs is When there is no time slot assigned to the local station in the TDMA frame,
In order to request the master station for a time slot (hereinafter simply referred to as slot) for requesting retransmission of the broadcast information, write the address of the own station in the slot reservation section of one of the subframes.6 Next, The master station that receives the slot assignment request from the slave station changes the slot assignment according to predetermined rules, and transmits the result to the slave station that requested (reserved) the slot before changing and allocating the outbound line. Notifications should be made using

[Effect]

According to the present invention, a TDMA frame on an inbound line is composed of a plurality of subframes, and each subframe includes a slot reservation part for a slave station to request time slot allocation from a master station, and at least one time slot. Since each slave station requests a time slot using the reservation section of an arbitrary subframe, the waiting time required to request a slot can be shortened. In addition, in response to time slot requests from each slave station, the master station changes the time slot allocation in the same TDMA frame and notifies each slave station of the result. Stations can use time slots within the same TDMA frame, increasing transmission efficiency.

〔Example〕

Embodiments to which the line control method of the present invention is applied will be described in detail below with reference to the drawings. First, before describing specific embodiments, an outline of the satellite broadcast communication system on which the present invention is based will be explained with reference to FIG.

FIG. 2 is a diagram showing the configuration of a satellite broadcast communication system consisting of a master station and a plurality of slave stations. In FIG. i)
(i = 1-n) indicates each slave station that is a receiving station, 6 is an outbound line, which is used when the master station transmits broadcast information to the slave stations, for example, TDM (
Time Division Multiplexer
) method is used. 5 is an inbound line.

For example, '1' is used when a slave station sends response information etc. to a master station.
ion MultipleAcce+ss) method is used.

Note that the present invention is applicable not only to satellite communication systems, but also to wireless communication systems, LAN (Local Area N)
It can also be realized in a wired communication system such as a network (e.g. network) or a switch having a broadcast function.

A first embodiment will be explained using FIG. 1. In FIG. 1, 6 is an outbound line and 5 is an inbound line.

The outbound line 6 consists of a control slot 61 and a data slot section 65. Control slots 61 are provided at regular intervals, and the master station (line control station) uses these slots to transmit a reference burst 62 used as a time reference for each slave station and a reference burst 62 to each slave station in a TDMA frame on the inbound line, which will be described later. A line control burst 63 containing information regarding slot assignment is included. The reference burst 62 is
It consists of a bit string with a specific bit pattern. A data burst containing broadcast information from the master station is arbitrarily sent to the data slot 65.

The inbound line 5 is composed of TDMA frames, and one 'I' DMA frame 5o is composed of a plurality of subframes 51. The subframe is composed of a reservation section 52 for a slave station to request time slot allocation, and a slot section 53 including at least one time slot.

The master station uses control slots 61 on the outbound line to allocate time slots of TDMA frames to each slave station for responses to previously broadcast broadcast information (not shown). The master station updates the contents of control slot 6D within the same TDMA frame in response to a response from the slave station, which will be described later. Consider a case where transmission information (for example, retransmission request 2 timing, etc.) is generated in a certain slave station during the above-mentioned broadcast communication operation.

If the slave station that has generated the transmission information has no slot assigned to it in the line-of-sight control burst 63,
Alternatively, if a new time slot is required for writing the above-mentioned transmission information in addition to the allocated slot, a time slot reservation request is made using an arbitrary slot reservation unit 52 (see 66 in FIG. 1). ), reservation request (
66), the master station changes part of the time slot allocation notified in the line control burst 63 in the control slot according to the reservation, and transmits the result to all slave stations using the slot allocation change burst 64. If the parent that received the reservation request is currently transmitting one broadcast information, the transmission is relayed and the slot allocation change burst 64 is transmitted preferentially. The slave station then inserts the transmission information into the newly assigned time slot.

The master station takes into account the propagation delay time, the processing time of the slave station, etc., and allocates a time slot at a timing that allows the slave station to transmit information in the minimum time.

According to the embodiment described above, a slave station to which no time slot has been assigned in a control slot, or a slave station that requires another time slot in addition to the assigned time slot, can reserve a time slot in any subframe. Since the time slot is reserved using the section 52, the waiting time until the reserved photon station transmits the transmission data can be eliminated, and efficient broadcast communication can be realized.

Using FIG. 3, the control slot 61 described above (see FIG. 3(a)
)) and slot allocation change burst 64 (Fig. 3(b))
The frame structure of will be explained.

The control slot 61 is composed of a reference burst 62 and a line control burst 63, which are composed of a bit string having a specific bit pattern. The IgI line control burst 63 is
For example, the line control burst 63 shown in FIG. 3(a), which includes an area equal to the number of sub-booms included in one TDMA frame, allocates the 111H time slot in the TDMA frame to the slave station 5(i). It shows the case.

In FIG. 3(b), 640 is a flag indicating that it is a slot allocation change burst 64, and a specific bit pattern is written therein to distinguish it from data. Reference numeral 641 is a change information section for storing line control change information, for example, as shown in FIG.
In the change control unit 641 shown in b), the line control burst 6
3 shows the case where the (n-1)th time slot assigned to the slave station 5(n-1) is changed to the slave station 5(j).

FIG. 4 is a frame configuration diagram of the 1' DMA frame 50 described above.

As shown in Figure 4(a), one '1' L) M A
The frame 50 is composed of a plurality of subframes 51, and each subframe is composed of a reservation section 52 and a slot section 53 including at least one time slot.

Furthermore, as shown in FIG. 4(b), the reservation section 52 consists of a plurality of areas, and each slave station makes a reservation by writing its own address in an arbitrary area.
In b), a case is shown in which the slave station 5(j) makes a reservation.

Next, as a second embodiment, the slave stations in the system are divided into groups, and each group sequentially returns a response to the broadcast communication from the master station (hereinafter, this method will be referred to as a rotating response method). The broadcast communication system will be explained.

Before describing specific embodiments, an outline of the satellite broadcast communication system on which the present invention is based will be explained with reference to FIG.

Figure 5 shows a satellite broadcast communication using a rotating response method in which there are n groups of a master station and a plurality of slave stations (in Figure 5, one group is made up of three slave stations to simplify the explanation). In FIG. 5, which shows the system configuration, 10 is a satellite, 20 is a master station that is a broadcast information transmitting station, and 5(i) (
i=-1 to 3) is a slave station which is a receiving station, G(k)(k=1
~n) indicates the group, 6 is the outbound line, 5
is an inbound line.

The master station 20 uses the data slot 65 on the outbound line via the satellite 10 to
) (i=1 to 3.=1 to n)). Below, the slave station 5(i) belonging to G(k) is 5(i).
It is written as G(K).

Broadcast information is divided into packets and sent, and the slave station returns a response for each packet.The response is returned in group units, and the master station specifies in advance the groups to which the rotating side will respond sequentially for each broadcast information packet. Specify using broadcast information. therefore,
The number of responses to one packet is equal to the number of slave stations making up the group, and the load on the master station is reduced compared to the case where responses are received from all slave stations. Note that if the track state is low, the slave stations belonging to two or more groups may be asked to respond to one broadcast information packet.

In the broadcast communication system shown in FIG.
)・G(k) will be described with reference to FIG. 6 regarding error recovery processing when a reception error occurs in broadcast information.

The master station uses control slot 61(a) to return response information to broadcast information (not shown) broadcast in advance.
is used to allocate slots to each slave station in the TDMA frame 50(a). Slave station 5(2)/G, which had been instructed in advance by the rotation side mentioned above to send back response information.
In (k), consider the case where a reception error occurs. When the slave station 5(2)/G(k) wants to use the slot assigned to it in the control slot 61(a) for a purpose different from the response, or when the slot is assigned in the control slot 61(a), If the slot is not available, it is necessary to request a new slot. Therefore, slave station 5(2)・G(k)
is subframe 51 in TDMA frame 50(a)
Using the reservation unit in (a), the master station makes a slot assignment request (reservation) (70). Having received the reservation 70, the master station requests the slave station 5 (
2) -aCk) is notified that the slot of subframe 51(b) will be allocated (71), and then the slave station 5(2)
・G(k) uses the slot of the subframe 51(b) newly allocated by the slot allocation change burst 64(a) to request retransmission of the broadcast information broadcast in advance (72), and the parent The station sends its retransmission request (72
), the broadcast information is retransmitted (73).

Next, the master station uses control slot 61(b).

In the slave stations 5(2) and G(k), which allocate time slots to each slave station in the TDMA frame 50(b), when it becomes necessary to newly allocate slots for the same reason as mentioned above, , the master station requests slot allocation (reservation) using the reservation part in the subframe 51(c) (74), and the master station notifies the slot allocation change using the slot allocation change burst 64(b) (75). , slave station 5
(2)・G(k) is the slot allocation change burst 64 (
b) Newly allocated subframe 51(d
) to respond to the retransmitted broadcast information (76).

According to the embodiment described above, when each slave station needs to secure a new slot due to a broadcast reception error or the like, it uses the reservation part of one of the subframes to request the master station to reserve a new slot. Since an allocation request can be made, error recovery by retransmission can be quickly performed without interfering with normal broadcast communication, and transmission time can be prevented from increasing.

In addition, if there are many reservations and a reservation conflict occurs in the slot reservation section, the reservation can be made in the next slot reservation section, or the master station can manage the reservation status and allocate the area in the reservation section to each slave station. By controlling the reservation traffic and avoiding collisions, more efficient communication becomes possible.

Note that when station m determines the subframes to be secured according to the reservation, after sending the slot allocation change (71), station The subframe is determined to be a subframe after 1/2 of the time required for a round trip. Specifically, the slot allocation change notification (71) described above is sent to the slave station 5 (2).
)・G(k) newly allocated subframe 51(b)
Try to do it earlier.

Next, the frame structure of the control slot 61 and the slot allocation change burst 64 on the outband line used in the above-mentioned broadcast communication system will be explained using Fig. 7.

FIG. 7(a) is a frame configuration diagram of the control slot 61 described above.As shown in FIG. Subframe specification section 6
31 and a slot identification section 632. The subframe designation section consists of a plurality of areas, each area corresponding to each subframe included in the TDMA frame 50, for example.

The subframe designation section 631 shown in FIG. 7(a) is '1'.
The first subframe of the DMA frame 50 is assigned to group G(3), and the third subframe from the end is assigned to group G(7).

The slot identification section 632 is composed of areas corresponding to the number of slave stations included in one group, and each area corresponds to each time slot included in the slot section 53 allocated to each group.

Details of the slot section 53 will be described later using FIG. 8, but each slot section consists of time slots equal to the number of slave stations included in one group. For example, in the case of FIG. 7(a), each group (G
(3), G(5)...G(n)), the first time slot is assigned to the slave station 5(3) of each group. ,
The second and third time slots are respectively assigned to the slave stations 5(1) and 5(2) of each group. Therefore, by using the subframe specifying section and the slot identifying section in this way, it is possible to allocate each slave station and each time slot in a one-to-one correspondence. Specifically, “
5" and "2" written in the third position of the slot identification section
The meaning shown by the combination means that the third time slot of the second subframe in the TDMA frame is allocated to slave station 5(2) and G(5).

FIG. 7(b) is a frame configuration diagram of the slot allocation change burst 64. The slot allocation change burst 64 is
As described above, the flag 640 has a specific bit pattern to distinguish it from data, the allocation change status section 642 is made up of a plurality of areas, and the allocation change instruction section 643 is made up of a plurality of areas corresponding to each of the areas. configured.

The master station, in accordance with the reservation 70 mentioned above,
(i), a new slot is assigned (71), but at that time, as shown in FIGS. 7(b) and (c), in the control slot 61, a new slot is In order to change the allocation of the time slot in the third subframe 51(b) to the slave station 5(2)/G(i), the address of group G(7) is assigned to an arbitrary area of the allocation change unit 642. Enter the group G(i) and slave station 5 (
Enter the address in 2). Therefore, each slave station receiving this slot allocation change burst 64 (a) will receive the subframe (i.e., T
It can be seen that the third time slot in the third subframe from the end in the DMA frame 50(a) has been reassigned to the slave station 5(2)/G(i).

Note that the allocation change status section 642 and the allocation change instruction section 6 described above
43 may have a fixed length or may have a variable length depending on the number of slave stations that have made reservations.

However, if the length is variable, use the flags mentioned above.

Include information indicating the slot length of each area.

Next, using FIG. 8, the above-mentioned TDMA frame 50
The frame structure of the subframe in (a) will be explained. The subframe 51(a) is composed of the reservation section 52 and the slot section 53 as explained in FIG. When the first subframe of the TDMA frame 50(a) is assigned to group G(3), each time slot in the slot portion 53 of the subframe 51(a) is divided into subframes as shown in FIG. 8(a). Station 5 (2)
・G(3), 5(1)・G(3), 5(3)・G(3
).

Further, the reservation section 52 is made up of a plurality of areas, and a slave station making a new slot allocation request enters the address of a group belonging to an arbitrary area and the address of its own station. Specifically, when the above-mentioned slave station 5(2)/G(k) makes a new slot allocation request using the reservation section 52 of the subframe 51(a), as shown in FIG. 8(b). As shown in <,
In one area 521, the address G(
Make a reservation 70 by filling in k) and your own address 5(2); therefore, the master station makes this reservation 70.
0, from slave station 5(2)・G(k), TDMA
The third of any subframe within frame 50(a)
learn that the second timeslot has been requested.

After that, the master station uses the slot assignment change burst 64(a) to notify each slave station of the slot assignment change, and the slave station 5(
2)-a(k) writes retransmission request information 72 in the third time slot in the assigned subframe 51(b), as shown in FIG. 8(0). Note that, as in the above-mentioned area 521, a unit of information consisting of a belonging group number and a slave station address will be hereinafter referred to as a slave station identifier.

Next, the configuration and operation of the master station 20 that implements the above-described broadcast communication system will be explained.

FIG. 9 shows the configuration of the master station 20. In FIG.
2 is a transmitting/receiving device, 22 is a line-of-sight control device, 23 is a broadcast communication control device, and 24 is an application. Before starting broadcast communication, the application 24 performs line control settings such as the number of groups in the system and the number of groups within a slave station. The line control device 22 and broadcast communication control device 23 are notified of the parameters necessary for this purpose. Broadcast information output from the application 24 is divided into packets by the broadcast communication control device 23, outputted to the signal line 26 for the outbound line 6 by the line control device 22, and transmitted from the transmitting/receiving device 21 to each slave station via a satellite. sent towards. On the other hand, the response information packet transmitted from the slave station via the signal line 26 for the inbound line 5 is
The broadcast communication control device 23 analyzes the response information packet and confirms that the slave station has received the broadcast information packet normally by transmitting a signal on the signal line. 27 to the line control device 22, and if there is a retransmission request (72 in Fig. 6) due to a reception error in the slave station, the corresponding broadcast information packet is sent to the line control device 22. .

The line control device 22 constantly monitors the inbound line, and creates control slots 61 and slot allocation change bursts 64 based on instructions from the broadcast communication control device 23 and reservations from slave stations.

Furthermore, the configuration and operation of the line control device 22 will be explained. 20
0 is an inbound control unit that receives TDMA frames, etc.; 201 is an outbound control unit that sends out TDM carrier waves; and 202 is a TDMA control unit on the inbound line 5.
2o3 is a multiplexing unit that multiplexes broadcast information packets; 204 is a buffer unit that temporarily stores broadcast information packets and retransmission packets; 2o5 is a buffer unit that temporarily stores broadcast information packets and retransmission packets; 202 is an interface section connected to the broadcast communication control device 23 via a signal line 27, and 202 is a clock control section that controls the clocks of each component device described above.

Note that the reservation unit monitoring unit 202 operates in a first mode in which an area in the reservation unit is fixedly allocated to each slave station, or in a second mode such as the straight Aloha method, depending on the number of slave stations written on the reservation unit. Control may also be performed in which one of the second modes for random access is selected and the result is notified to each slave station using the data slot unit 65.

Next, the operation of the line control device 22 will be explained with reference to FIG. 10, focusing on the flow of processing performed by the reservation section monitoring section 202.

As described above, the reservation unit monitoring unit 202 receives parameters such as the number of groups in the system and the number of slave stations in each group from the application 24 in advance via the broadcast communication control device 23 and the interface unit 205. , is stored (step 202a).

Note that the broadcast information output from the application 24 is
The signals are multiplexed by the multiplexing unit 203 via 23, 205, and 204, and transmitted to the slave station via 201 and 21.

After transmitting the broadcast information, the reservation unit monitoring unit 202 determines the allocation of slots in the TDMA frame to each slave station based on the parameters described above, and uses the control slot (61 ) (step 202b), each slave station sends back response information, etc. using each slot allocated in the control slot (61) transmitted from the master station, and also receives similar information. As described above, the slave station in which the error has occurred makes a new slot allocation request using an arbitrary reservation part of the TUNA frame. It is determined whether or not an address has been written. If the address has been written, the process branches to step 202d, and if it has not been written, the process branches to step 202g.

In step 202d, the address of the slave station is read from the reservation section, and in step 202e, the slot to which the assignment is to be changed to the slave station is determined. Note that when the reservation unit monitoring unit 202 determines the slot to be changed in allocation, for example, TD
A slot management table created from the clock timing of each slot in the MA frame and the order of slave stations assigned to each slot in the control slot is referred to (not shown).

In step 202f, a slot allocation change burst is created in order to notify the slot allocation change, and the multiplexer multiplexes the burst and sends it to each slave station via the interface unit 205 and buffer unit 204.

In this way, in response to slot allocation requests from slave stations,
When slot allocation within a TDMA frame is changed, it is necessary to secure the corresponding slot in subsequent TDMA frames until the changed slot is actually used. Therefore, in step 202g.

It is determined whether or not the slot has been used, and if it is confirmed that the slot has been used, the slot is canceled in step 202h. Specifically, the slot is corresponded to the slot that was subject to slot allocation change in step 202θ. The flag is set in the internal memory, and the flag is left set until the use of the slot is confirmed in step 202g. Even if there is a slot allocation request from another slave station, the flag is not set. The slot that has been set is excluded from the slots to be reassigned, and when the use of the slot is confirmed, the flag in the memory is deleted in step 202h. Therefore, 1 in memory
If no flag is set, step 202g
Since there is no need to make a judgment, the process branches to 202i. In step 2021, the clock controller 208 transmits the TDMA signal.
The end timing of the frame is detected, and if the frame has not ended, steps 202o to 202h described above are repeated, and if it has ended, the process branches to step 202j. Step 20
2j, the slot allocation for the primary TDMA frame is determined, and step 202b is then repeated.

Note that the setting of the flag in step 202e described above remains valid unless it is canceled, so step 2
When determining the slot allocation of 02j, the allocation of the corresponding slot is not changed.

FIG. 11 is a block diagram of the slave station 5(i). In the figure, 30 is a transmitting/receiving device, 31 is a line control device,
32 is a broadcast communication control device, and 33 is an application.

The broadcast information packet is sent to the transmitting/receiving device 301 and the line control device 31
It reaches the broadcast communication control device 32 through the. The broadcast communication control device 32 checks the broadcast information packets for errors, etc., and if the broadcast information packets are received normally, integrates the broadcast information packets and transmits them to the application 33. When an error occurs, a reservation request signal is sent to the line control device 3 in order to secure slots for sending retransmission request packets and retransmission response packets. The line control device 31 that received the reservation request signal,
In order to reserve a slot, a retransmission request packet is placed in the slot allocated by the reservation and sent to the satellite from the transmitting/receiving device 30.

Furthermore, the configuration and operation of the line control device [31] will be explained. 30
0 is an inbound control unit, 301 is an outbound control unit, and 302 is a burst monitoring unit.

303 is a retransmission control unit, 304 is a demultiplexer, 30
Reference numeral 5 indicates a buffer section, and 306 indicates an interface section. The interface section 306 is connected to the broadcast communication control device 32i via a signal line. Further, 307 is a clock control unit, which performs clock control of each component device.

To explain the operation of the line control device 31, the processing flow of the burst monitoring section 302 and retransmission control section 303 is shown in FIG. 12 and FIG. Performs line control processing when there is no.

In FIG. 12, the burst monitoring unit 302.

The reference burst 62 is monitored in step 302a. Note that the clock control unit 307 is notified of the detection of the reference burst by the burst monitoring unit 302, and therefore controls the clocks of each component device based on the detection timing.

In step 302b, one line control burst is read out and stored in the internal memory. In step 302c, it is determined whether the subframe designation section 631 of the line control burst 63 contains the number of the group to which the local station belongs. If the group number to which the station belongs is empty, it is determined that no slot is allocated, and the process returns to step 302a. In step 302d, it is determined whether there is transmission information.

If there is none, the process returns to step 302a. Specifically, in order to check the presence or absence of transmission information, the burst monitoring unit 302
First, a packet request signal is output to the buffer unit 305 via the signal line 351, and the buffer unit 305 responds to the signal and notifies the burst monitoring unit of the presence or absence of transmission information. In step 302e, according to the timing signal from the clock control unit 307, transmission information is sent out using the allocated slot.

Next, retransmission control performed by retransmission control section 303 will be explained using FIG. 13.

In step 303a, the presence or absence of a reservation request signal from the application 33 indicating whether there is a new slot allocation request is detected via the signal line 353. If there is no reservation request signal, the process returns to the original state.

In step 03b, the TD from the clock control unit 307 is
In response to the notification of entry timing in the reservation section on the MA frame, the own station's address (group number, group number,
Enter the sub-station address within the group. Step 303
In C, in response to a slot assignment change request, the presence or absence of a slot assignment change burst from the master station is monitored to confirm whether slot assignment has occurred. In step 303d, the clock controller 30 is placed in the newly allocated slot.
In response to the entry timing notification from 7, the retransmission request packet is written.

This completes the explanation of the operations of the burst monitoring section 302 and the retransmission control section 303, and returns to FIG.
The operation of step 1 will be explained.

The broadcast information packet is sent to the outbound control unit 301 via the signal line 41. Broadcast communication control device from interface section 306 through demultiplexer 304! 32 via the signal line 42, the response information packet created by the broadcast communication control device 32 is sent to the interface unit 3 via the signal line 42.
06 and is temporarily stored in the buffer section 305. In response to the packet request signal from the burst monitoring section 302, a response information packet is output from the inbound control section 300 to the signal line 40 through the burst monitoring section 302. When there is an error in the received broadcast information packet, the retransmission request packet and retransmission response packet from the broadcast communication control device 32 are temporarily stored based on a request from the retransmission control unit 303. Buffer unit 305 outputs a reservation request signal to signal line 353. The retransmission control unit 303 makes a slot reservation and outputs the retransmission request packet or retransmission response packet received from the signal line 353 to the signal line 352.

Next, a third embodiment will be described in which each slave station performs one-to-one communication or scheduled communication in a broadcast communication system to which the present invention is applied. Note that the premised system is the same as that shown in FIG.

FIG. 19 shows the configuration of the slot reservation unit 52 used in the third embodiment. Since the slot reservation unit 52 is composed of a plurality of areas as described above, the explanation will be omitted.

However, the difference is that one area (reservation slot) 522 includes a flag in addition to the slave station identification section. The meaning of the flag consisting of 2 bits and 1 will be explained using FIG.

Flag 01'' means retransmission, flag 11'' means start of timing/one-to-one communication, and flag 11'' means completion of alignment/one-to-one communication.

Next, we will explain the outline of the line control for realizing the third embodiment. The 0-adjustment slave stations are 5(2) and G(1) in FIG. 5, and the slave stations 5(2) and G( 1) sets the flag of the reservation slot 503 to "11" and writes the own station address in the slave station identification section in order to reserve a slot for making time. The master station 20 is
When the flag "11" is received, slots are allocated as described above, and the next and subsequent TDMs are allocated until the flag "10" is received.
Secure the corresponding slot of the A frame. Child station 5 (2
).G(1) executes the inquiry using the allocated slot, and sets the flag to "10" after completing the adjustment.

According to the third embodiment described above, it is possible to reliably secure a slot from the start to the completion of an inquiry, and it is also possible to make multiple arrangements, thereby expanding the service. Naturally, since there are multiple reservation units 52 in the TDMA frame, inquiries can be made at any time.

Next, as a fourth embodiment, a case will be described in which, in the above-mentioned broadcast communication system, scheduled communication is carried out under centralized management or distributed management.

When a matching station matches multiple slave stations, there are two methods for securing slots by reservation. One of them is a method in which the arranging station reserves slots for use in responding to stations that have received the inquiry (hereinafter referred to as responding stations) for the number of responding stations, as described above. If the line usage rate is high and it is not possible to secure slots for the number of responding stations, only the slots that can be secured are used and the responding stations are made to respond by setting a time difference.

Another method is for each responding station to make a reservation and secure a slot for responding on time.

That is, whether to make reservations through centralized management or through distributed management.

In this way, a slot can be reliably secured for the 1-matching response, and the 1-matching station can receive the response reliably and quickly. Furthermore, by making reservations all at once, it takes less time to secure a time slot.

However, this centralized management poses a problem in that the load placed on each coordination station increases. Overload occurs especially when traffic is concentrated at the coordination station.

Therefore, if the load is distributed to the responding stations, the load on the arranging station can be reduced, but with one distributed management, there are cases where different responding stations are unable to make reservations immediately due to collisions, etc. In such cases, the response is delayed and time is wasted in making adjustments, so depending on the situation, switch to centralized management.

As described above, by combining centralized management and distributed management and switching the method of securing slots as appropriate according to the traffic volume of the arranging station or response station, flexible inquiry line control can be achieved in response to fluctuations in traffic volume. Can be executed. In reality, one can be selected by selecting system parameters (number of groups, number of subframes, number of slots, number of reserved slots, etc.) that match the environment (weather conditions, frequency of inquiries, etc.) during system design.

Third. Slave station line control device 31 realizing the fourth embodiment
The operation will be explained using FIG.

As a premise, the application 33 sends a communication start signal and a communication completion signal to the line control device 31 via the broadcast communication control device 32 at the start and end of timing and one-to-one communication.
Send to.

In step 160a, the burst monitoring unit 302 detects whether or not a communication start signal is input from the signal line 351, and returns to the original state if there is no input. In step 160c, in accordance with the timing signal from the clock control section 307, "11" is written in the flag of the reservation section 52, and the address of the own station is written in the same area. The master station changes the slot allocation and sends a slot allocation change burst to each slave station, so in step 160c, it monitors whether or not the slot allocation has been changed to its own station, and if there is a notification.

In step 160d, transmission information is written using one slot allocated according to the timing signal from the clock control section 307. At step 160θ, one communication completion signal is detected, and if there is no signal, step 16 is performed again.
At 0d, transmission information is written using the corresponding slot of the next TDMA frame. Step 16 above
If a communication completion signal is detected at 0c, the reservation unit 5
"10" is entered in the flag No. 2, and the address of the own station is entered in the slave station identification section (step 160f).

In this case, the process performed by the master station is to read out the flag in addition to the slave station address in the tenth step 202d, and in step 202g, in addition to confirming the use of the slot, it also sets the flag in the reservation section to "10". ” only when it detects that it has been filled in.

The process is the same as that described in FIG. 10, except for branching to step 202h.

Furthermore, as mentioned above, when performing line control by switching between centralized management and distributed management, it is desirable that the intermediary station be able to instruct the master station whether to perform centralized management or distributed management. As Example 5, a broadcast communication system will be described in which a slave station can arbitrarily select either centralized management or distributed management.

The system configuration is the same as that in FIG. 5, so a description thereof will be omitted.

FIG. 17 is a diagram for explaining the frame structure of the reservation section 52 used in the fifth embodiment described above.

In FIG. 17, the slot reservation section 52 has a plurality of areas 5
It consists of 23 (reservation slots).

Consists of the number of cuts. Regarding the flag and slave station identification section, see Chapter 14.
As explained in the figure. The explanation of the number of slots is in the 18th
Do it with diagrams.

In FIG. 18, the number of slots "0" realizes slot reservation by one distributed management. The master station that recognizes the reservation slot with the number of slots "0" allocates the slot only to the arranging station. When the number of slots is not "0", the master station recognizes that inquiry slot reservations are to be centrally managed and allocates slots to the arranging station and the responding station.

Notification to the responding station as to whether centralized management or distributed management is to be carried out is carried out using a timing information packet. Fig. I9 shows the format of the timing information packet.

The basic configuration complies with HL)LC.

The timing information packet 444 includes the F (H start flag) section 44
4a, A (address) section 444b, and C (control) section 4
44C, and an l (information) section 444d.

Fe2 (frame inspection sequence) unit 444e and F
(end flag) section 444f.

Also, the last bit of the C (control) part is the management identification bit 4.
44g, if the bit is set, it indicates distributed management,
・The responding station immediately makes a slot reservation. If the bit is not set, it indicates centralized control and waits for a timing information packet.

〔Effect of the invention〕

As is clear from the above description, the line control method of the present invention is applicable to a broadcast communication system in which a master station and a plurality of slave stations communicate with each other using inbound lines and outband lines having different frequencies.

High transmission efficiency can be obtained, particularly in two-way retransmission processing of broadcast information or in one-to-one communication.

[Brief explanation of drawings]

FIG. 1 is a frame configuration diagram from an inbound line and outband perspective of a broadcast communication system to which the present invention is applied, FIG. 2 is a schematic diagram of a broadcast satellite communication system to which the present invention is applied, and FIG. FIG. 4 is a frame configuration diagram of a control slot and slot allocation change burst on an outbound line. FIG. 4 is a frame configuration diagram of a '1' DMA frame on an inbound line. FIG. A schematic diagram of the broadcast communication system in the embodiment, FIG. 6 is a diagram for explaining error recovery processing when a reception error occurs in a slave station in the broadcast communication system of FIG. 5, and FIG.
FIG. 8 is a detailed frame configuration diagram of control slots and slot allocation change bursts in the broadcast communication system shown in FIG. Figure 5 is a block configuration diagram of the master station in the broadcast communication system, Figure 10 is a flowchart of the processing carried out by the line control device in the master station, and Figure 11 is the block configuration of the slave station in the broadcast communication system in Figure 5. Figure 12 is a flowchart of the processing performed by the burst monitoring unit in the slave station, Figure 13 is a flowchart of the processing carried out by the retransmission control unit in the slave station, and Figure 14 is the reservation unit used for timing and factory-to-factory communication. Frame configuration diagram, No. I5
The figure shows the correspondence between bit strings of flags in a reservation section and their meanings. Figure 16 shows a slave station that performs timing and one-to-one communication.
-X)-Monitoring unit 0 processing 70-chart - Figure 17 is a frame configuration diagram of the reservation unit when line control is performed by centralized management and distributed management in a broadcast communication system.
This figure shows the correspondence between the number of slots included in the reservation section of FIG. 17 and their meanings. FIG. 19 is a diagram showing the format of the timing information packet. 5... Inbound line, 6... Outband line, 10... Satellite, 20-... Master station, 5(i) (i=
1 to n)...Slave station, 50...TDMA frame, 5
1...Subframe, 52...Reservation section, 53...
Slot part, 61... Control slot, 62... Reference burst, 63... Eye control burst, 64... Slot allocation change burst, 65... Data slot part. ￥J 2nd 3rd Figure I 40 4-l Da diameter 6 Me IO Zukan Zutaku 1 Ward power! 4 ■ Yu5 Figure Yu/7 Figure 8

Claims (1)

[Claims] 1. A master station and a plurality of slave stations use inbound lines and outbound lines with different frequencies, and the master station transfers each time slot in a TDMA frame on the inbound line to the outbound line. In the line control method for a communication system, the TDMA frame is allocated to each slave station using the control signal of the TDMA frame, and each slave station transmits information to the master station using the assigned time slot. Each subframe consists of a slot reservation part for requesting the master station to allocate a time slot and at least one time slot, and each slave station can use any subframe in one TDMA frame. Using the slot reservation section,
A line control method characterized in that a time slot allocation request in the TDMA frame is requested. 2. A master station and a plurality of slave stations use inbound lines and outbound lines with different frequencies, and the master station controls each time slot in a TDMA frame on the inbound line using control signals on the outbound line. In the line control method for a communication system, the TDMA frame is composed of a plurality of subframes, and the TDMA frame is configured to include a plurality of subframes. Each subframe consists of a slot reservation part for requesting the master station to allocate a time slot and at least one time slot, and each slave station can use the slot reservation part of any subframe in one TDMA frame. ,
The master station makes a time slot assignment request in the TDMA frame, and in response to the time slot assignment request from the slave station, the master station outputs the signal for changing the time slot assignment in the TDMA frame. A line control method characterized in that transmission is performed to each slave station using a band line. 3. A master station and a plurality of slave stations use inbound and outbound lines with different frequencies, and the master station controls each time slot in a TDMA frame on the inbound line using control signals on the outbound line. In a line control method for a communication system, the TDMA frames are allocated to each slave station, and each slave station transmits information to the master station using the allocated time slots, and a plurality of slot reservation parts for requesting the master station to allocate time slots, and each slave station uses any slot reservation part in one TDMA frame to The master station makes a time slot assignment request, and in response to the time slot assignment request from the slave station, transmits a signal for changing the time slot assignment of the TDMA frame to each of the outband lines. A line control method characterized by transmitting data to a slave station. 4. The master station transmits the signal for changing the time slot assignment before the time slot in the TDMA frame newly assigned to the slave station that has requested the time slot assignment. The line control method according to claim 2 or 3, characterized in that: 5. A master station and a plurality of slave stations use the same inbound line and outbound line with different frequencies, and the master station controls each time slot in a TDMA frame on the inbound line using a control signal on the outbound line. In the co-channel control method for a communication system, the TDMA frame is allocated to each slave station, and each slave station transmits information to the master station using the allocated time slot. Each subframe consists of a slot reservation section for requesting the master station to allocate a time slot and at least one time slot, and each slave station receives errors in receiving broadcast information broadcast in advance from the master station. occurs, using an arbitrary slot reservation part in one TDMA frame,
The master station makes a time slot assignment request in the TDMA frame, and in response to the time slot assignment request from the slave station, the master station sends a signal to the antbound to change the time slot assignment in the TDMA frame. The signal is transmitted to each slave station using a line, and the slave station that has requested the time slot allocation uses the signal to request retransmission of the broadcast information using the newly allocated time slot. line control method. 6. The master station includes in the broadcast information the address of at least one slave station that should respond to the broadcast information, and transmits the TDMA frame or the next one until it receives predetermined information from the slave station. 6. The co-line control method according to claim 5, wherein allocation of time slots to said slave stations within a TDMA frame is not changed. 7. A master station and a plurality of slave stations use inbound lines and outbound lines with different frequencies, and the master station controls each time slot in a TDMA frame on the inbound line using control signals on the outbound line. In a line control method for a communication system, the TDMA frame is composed of a plurality of subframes, in which the TDMA frame is allocated to each slave station, and each slave station transmits information to the master station using the allocated time slot. , each subframe consists of a slot reservation part for requesting the master station to allocate a time slot and at least one time slot, and each slave station uses one TDMA when performing time adjustment or one-to-one communication. The TDM uses the slot reservation part of any subframe in the frame.
A time slot allocation request is made in the A frame, and the master station responds to the time slot allocation request from the slave station,
A signal to change the allocation of time slots in the TDMA frame described above is sent to each slave station using the above outband line, and the slave station that requested the allocation of the time slot receives the newly allocated time using the above signal. A line control method characterized in that information for the inquiry or one-to-one communication is transmitted using slots.