JPS6320061B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a satellite communication method in which terminal stations on the earth communicate data between each other via a space station installed in outer space, and in particular, the present invention relates to a satellite communication method in which terminal stations on the earth communicate data between each other via a space station installed in outer space. After first securing a time slot for data transmission using a reservation signal,
By transmitting data signals using the time slots, the number of slots required for reservation signals is reduced when data communication is performed between terminal stations. [Prior Art] Satellite data communication is characterized by its large transmission capacity, which allows it to be used jointly by a large number of terminal stations on the ground. In the future, it may become commercially viable if a large number of terminal stations share use. In satellite data communications, data communication between terminal stations is performed via a transmission channel via a space station, but in this case, if multiple terminal stations transmit data at the same time, mutual data interference may occur. A so-called data collision occurs, in which the correct data does not reach the desired partner station due to mutual interference. To deal with this, the time axis is divided into time slots (small pieces), and these time slots are further divided into time slots for reserved signals and time slots for data signals, and the reserved time slots are used first. Each terminal station is made to reserve how many time slots it needs to transmit data signals, and the reserved number of time slots for data signals are prepared for that terminal station. Transmit the data signal using the data signal time slot prepared for you. Furthermore, if each terminal station transmits a reservation signal every time a data signal that it wants to transmit occurs, a collision of reservation signals will occur. The conventional method was to allocate one to each. [Problems to be solved by the invention] However, in the conventional system as described above, as the number of terminal stations on the ground side that share the satellite increases, the same number of time slots for reservation signals are also required, and the data A problem arises in that the transmission processing capacity decreases and the data transmission waiting time increases when viewed from a single terminal. Furthermore, considering the actual communication conditions, the data generation rate is not that high, and even if all terminal stations are provided with one time slot for reserved signals, most of the data is expected to be wasted. . SUMMARY OF THE INVENTION An object of the present invention is to provide a satellite communication method capable of solving the above-mentioned problems of the prior art, reducing the number of time slots allocated to reserved signals, and improving data communication processing capacity. [Means for Solving the Problems] In order to achieve the above object, the present invention has the following features:
Create and transmit at least two types of groupings that divide all terminal stations into multiple groups such that each terminal station belongs to one group and each group includes approximately the same number of terminal stations. The polling to inquire of the terminal station whether or not there is the desired data is carried out sequentially for each of the above types for each group, with the number of time slots allocated to the reservation signal being one per group. There is a way to do it. [Embodiments and their effects] The present invention will be explained below with reference to the drawings. FIG. 1 is an explanatory diagram of a signal control state during satellite data communication. In Figure 1, S is a space station and T ₁
~T _N are N terminal stations on the earth, and
A control station C common to N terminal stations T ₁ to T _N is installed on the earth in order to manage polling that inquires whether each terminal station has data to be transmitted. The control station C includes a circuit unit _C1 that manages polling, and a circuit unit C1 that manages the allocation of time slots for data transmission to terminal stations T _i (where i is any number from 1 to N) that has responded to the polling. circuit section
C ₂ and a circuit section C ₃ that controls signal processing in these circuit sections C ₁ and C ₂ . In addition, each terminal station T ₁ to T _N has a circuit section T _R1 to T RN that responds to polling, and a circuit section T R1 to _{T RN} that transmits data signals to other terminal stations using the allocated time slot for data transmission. There _are provided circuit units T _S1 -T _SN for controlling signal processing in these circuit units T _R1 -T _RN and _{T S1} -T _SN , respectively. In such a configuration, conventionally, each terminal station
One reserved signal time slot is allocated for each of _T1 to _TN , and the control station C sends the signals to each terminal station according to a predetermined order, regardless of whether there is a data signal to be transmitted. A method was used in which polling was performed for each station in sequence and a response was obtained. However, as mentioned above, this conventional method is wasteful. Therefore, in the present invention, as shown in an example in FIG. 2, N terminal stations are divided into multiple groups, each group includes approximately the same number of terminal stations, and each A time slot for reservation signals is allocated and group polling as described below is performed. Furthermore, create at least two types of grouping as described above, and first perform group polling on each group according to the first type of grouping, and after this, perform group polling on each group according to the second type of grouping. Perform group polling on Group polling is continued in the same manner, and when all types of polling are completed, one cycle of polling is completed. FIG. 2 shows a case where the number of groups is m and the number of types is 2. Since the number of groups is m, each group includes approximately N/m terminal stations. 1 means grouping according to the first type, and 2 means grouping according to the second type.
The first type 1 is divided into m groups of a ₁ , a ₂ , a ₃ , ......a _n , and each group a ₁ to a _n includes approximately N/m terminal stations. I'm here. The second type 2 is divided into m groups b ₁ , b ₂ , b ₃ , and b _n , and each group b ₁ to b _n includes approximately N/m terminal stations. . Then, each terminal station is necessarily included in one of groups a ₁ to _{a n} , and is also necessarily included in one of groups b ₁ to b _n . Make it. For example, group polling is first performed for the first type 1 in the order of a ₁ → a ₂ → a ₃ ...... → a _n , and after these m group pollings are completed, the next type 2 Move to b ₁ → b ₂ → b ₃ ………
→ b _n in this order, and one cycle of polling work is completed. Therefore, the number of group polls in the case of Figure 2 is 2× within one cycle.
This is m times. For this group poll,
A terminal station belonging to that group issues a reservation signal if it has a data signal that it wants to transmit. If there is only one terminal station in the group that outputs a reservation signal, the reservation signal is accepted, a time slot for data transmission is allocated, and data transmission becomes possible. The terminal station that has finished transmitting data will
A reservation signal is not issued until the next data to be transmitted occurs. In the above case, if there are two or more terminal stations outputting reservation signals in the same group, the reservation signals will collide. However, if the grouping according to the first type 1 and the grouping according to the second type 2 are made to have different combinations of terminal stations in the groups, the reservation signal can be processed by group polling for the first type 1. Even if a collision occurs,
When the group polling for the second type 2 is performed, the number of terminal stations that output the reservation signal is the same as the number of terminal stations that receive the reservation signal during the group polling for the first type 1, except for terminal stations that newly generate data.

【table】

Claims (1)

[Claims] 1 Multiple terminal stations on earth use a space station installed in outer space as an intermediary, using time-divided time slots to first secure a time slot for data transmission using a reservation signal, and then transmit data signals. In a satellite communication method that performs data communication between mutual stations, all terminals are divided into multiple groups so that each terminal station belongs to one group, and each group has approximately the same number of terminal stations. Create at least two types of grouping to divide the stations, and polling to inquire of the terminal station whether there is data to be transmitted or not, with the number of time slots allocated to the reservation signal being one per group, first. A satellite characterized in that polling is performed for each group according to one type of grouping, and then for each group according to a second type of grouping, and when all types are completed, one cycle of polling ends. Communication method.