JPS60236525A - Carrier wave hopping controller for tdma satellite communication - Google Patents

Abstract

PURPOSE:To attain a change of the hopping control at all times and to facilitate an easy alternating system for reference station, i.e., the original purpose, by including a code for selection of a carrier wave related to a relevant event and a control code showing whether said selection is fixed or variable into the control information. CONSTITUTION:A code HOP (Fa) for selection of a carrier wave Fa is usually recorded to a time slot containing a reference burst. In this case, a control code C displays a ''variable'' state. While a code HOP (Fb) for selection of a carrier Fb that can receive a spare reference burst is held by a register or a manual digital switch 324. When a signal 363 showing that the reference burst is lost is produced, this signal is applied to an AND gate 328. Then an AND is secured with the information on the code C, and a data selector 326 is switched. As a result, the code HOP (Fb) is selected only for the time slot containing the reference burst.

Description

Detailed Description of the Invention (Technical Field of the Invention) This invention relates to time division multiple access (Ti
m@Dlvision Multiple Access
The present invention relates to a carrier hopping control device used in an earth station device of a satellite communication system (hereinafter referred to as TDMA).

(Technical Background of the Invention) In a TDMA satellite communication system, multiple earth stations communicate with each other by using carrier waves of the same frequency and sharing the corresponding frequency bands of satellite repeaters (transponders) in a time-sharing manner. It is a system that

FIG. 1 is an explanatory diagram of such a TDMA system. It is assumed that four earth stations A, B, C, and D participate in this system.

Each station transmits traffic data of 1.2
．． 3 and 4) (
Burst), one frame structure called a TDMA frame is created, and this is periodically repeated. These nodes must be controlled on the transponder so that they do not interfere with each other.

In the TDMA system shown in Figure 1, each station uses TDMA7
It transmits its own traffic data using /4 of the frame. This shows that if only one carrier wave is used, the data destined for the own station is only 1/4 of the total received data even during reception.

In other words, each station uses only 1/4 of its transmission/reception capacity, but if an appropriate method is used, the communication capacity of each station can be expanded up to four times. Here, the technique of carrier hopping is used.

FIG. 2 shows a case where carrier hopping is used as a means of expanding the communication capacity described above. In (2) of the same figure, (
Each station A, B as shown in () to ).

C and D are independent frequencies fa1fb.

It transmits its own data using almost the entire frame using fa and fd carrier waves. These detectors are divided into bursts, such as i, 1', i', . . . , depending on the receiving station.

Even though the bursts transmitted from each station use different frequencies, they must be synchronized with each other in time on the satellite, as shown in the figure.

Generally, the frequency of the carrier wave is converted when passing through a transponder, so this is converted into Fa, Fb, Fc, and Fd.
shall be.

FIG. 2B shows the result of carrier hopping in reception at earth station B.

For example, the B station collects only the bursts transmitted from each station to the B station by switching the carrier waves to be received within the TDMA frame according to a predetermined procedure, and forms a reception frame similar to that on the transmitting side. As a result, each station can maximize its transmission and reception capabilities.

Now, one of the most important functions to maintain a TDMA system.
The first is "synchronization." This synchronization includes frame synchronization and burst synchronization.

An important issue regarding synchronization is how to smoothly replace the reference station with another station taking over the role of the reference station when a failure occurs in the reference station that provides frame synchronization in the TDMA system. It is. First, let us consider the case where multiple earth stations use carrier waves of the same frequency.

In FIG. 1, station A serves as a reference station and transmits a burst containing a frame synchronization signal IO, and each station receives this to establish two-frame synchronization.

Now that a failure has occurred in station A, one way for station B to play the role of a reference station in place of station A is to change the synchronization signal 20 included in parse 2 transmitted by the station to a frame synchronization signal. However, each station resynchronizes using this new frame synchronization signal. One example of such technology is the 1975
U.S. Patent No. 3.878,33, published on January 15, 2016
No. 9 (W, G, Maillet 'Referen'
ce 5tation Failure in a T
DMA System").

However, this method has the drawback that the position of the frame synchronization signal changes every time the reference station is replaced.

Therefore, as a next method, a method was considered in which the reference station sends a special burst containing a frame synchronization signal but not traffic data at the beginning of the TDMA frame as shown by the broken line 11 in FIG. In this case, this special burst is called a reference burst, and the burst containing other traffic data is called a data burst. When a reference station is replaced using this method, a predetermined backup reference station newly transmits a reference burst to the same position on the TDMA frame where the previous reference station was transmitting a reference burst. become.

This method is described in U.S. Pat. No. 3,838,211, published September 24, 1974 (W.G. Schmidt
etal'TDMA 5atellte Comm
unication System having 5p
However, in this system where there is only one reference burst at the beginning of the frame, after the loss of the regular reference burst, it is difficult for the backup reference station to send out a replacement reference burst. The problem is that it takes several seconds, and for a period of seven seconds, other stations must operate without the reference burst.

As a way to solve this problem, each earth station receives its own transmission burst via a satellite and uses the synchronization signal shown in Figure 1 included in the transmission burst to establish the timing of its own transmission burst. 20.30 and 40 are extracted from each data burst, and 21.31 and 4 in Fig. 3 are extracted.
This is a method of allocating them all at the beginning of the frame as shown in 1. These are called synchronous bursts.

This method can separate the parts related to synchronization and the parts related to traffic data transmission, and can take full advantage of the flexible nature of the TDMA system.

In addition, in this case, since the synchronization burst 21 of the backup reference station (for example, station B) is also transmitted, if the reference burst is lost due to a failure, other stations will immediately use the synchronization signal in the burst of the backup reference station as a frame synchronization signal. can be used to maintain synchronization. The advantage of this method over the reference station replacement method described above is that it does not take much time for the backup reference station to send out the reference burst, and the position of the synchronization burst (or backup reference burst) of the backup reference station on the frame is determined in advance. It is possible for each station to design the frame synchronization circuit in its receiving device according to this frame structure, that is, it is possible to establish frame synchronization using either the reference burst or the preliminary reference burst. The point is that it is possible to configure it so that it can be maintained. This method was introduced in 1980.
Special Publication No. 55-47781 (Watanabe, et al.) announced on December 2nd.
"Time Division Multiple Access Communication System" (Japanese Patent Application Laid-Open No. 51-5914).

Also, the 3rd International Conference was held in Kyoto from November 11th to November 3rd, 1975.
enceon Digital 5atellite
Communications by Watanabe, et al.
New TDMA System for Domes
ticService and its HLgh 5
peed PSK Modem”, and is currently being used as Japan's practical communication satellite [Sakura 2J (C8-2)].
It is used as a TDMA system using Nippon Telegraph and Telephone Public Corporation's lines.

Note that a method of arranging the reference burst and the preliminary reference burst on the same frame is described in US Pat. No. 4,054,753 (p.

Kaul et al'Double 5yne Bu
rst TDMA System).

As shown in Figure 3, the method in which all related earth stations transmit synchronization bursts every frame reduces frame efficiency, that is, the proportion of the portion of the TDMA frame that can be used for transmitting traffic data, as the number of stations increases. There is a difficulty in storing it. In addition, as a recent trend, the role of reference stations in communication systems is becoming more important, and they do not only provide a time reference for frame synchronization, but also transmit control commands for remote control of each earth station. , the length of reference bursts has become longer in order to transmit data for downloading to control computers used in each earth station, and the length of such reference bursts and spare reference bursts of the same shape are becoming longer. It is uneconomical to arrange them on the same frame.

Here again, the problem of synchronization in TDMA systems, particularly the carrier hopping technique for performing reference station switching most efficiently and safely when a plurality of carrier waves are used, is brought into focus. Regarding this technology,
This is described in ``Reference Station Alternation System for TDMA Satellite Communication System Having Carrier Hopping Function'' by the same inventor, which was filed at the same time as the present invention.

This will be briefly explained below. In the above invention, the backup reference station transmits the backup reference burst on the TDMA frame at the same time position as the reference burst, but using a different carrier.

Each station has at least a carrier hopping function on the receiving side and can receive at least carrier waves related to the reference burst, local station synchronization burst, and the preliminary reference burst described above, and when the reference station is operating normally, The frame synchronization burst synchronization is maintained by receiving the reference burst and the local synchronization burst.

If a failure occurs in the reference station and a reference burst is lost, each station changes its carrier hopping control and uses the carrier associated with the preliminary reference burst at the position of the reference burst on the TDMA frame. By selecting , it is possible to receive the preliminary reference burst and continue to perform frame synchronization and burst synchronization without any problems.

Thus, the importance of carrier hopping techniques in TDMA systems is recognized.

There are two cases for carrier hopping described here:
That is, there is transponder hopping and frequency hopping. Transponder hopping is TDM in Figure 1.
This is a technique used when the A system uses a transmission frequency of, for example, 60 Mbps, and utilizes the entire band or power of one transponder, and in order to obtain multiple carrier waves, It is necessary to use multiple transponders within the same satellite.

Frequency hopping itself may seem to have a broad meaning, but typically TDMA systems, which use only a fraction of the bandwidth and power of one transponder at low speeds, e.g. 10 Mbps, are Refers to the technology used to expand the scale by using multiple carrier waves within a bonder. Since the present invention can be applied to both cases, they are collectively referred to as carrier wave hopping. However, to simplify the explanation, an example of transponder hopping will be described below.

(Prior Art and Problems) A control device used for transponder hopping or carrier hopping in general is described in the aforementioned U.S. Pat.
, 838,211 and other U.S. patents, such as No. 4,115,661 (W, G,
Sch dt, 'Single Channel
Per BurstTDMA Multiple Tr
angponder Netvrork Riya, 1979
Publication No. 4,135,059 (W, G
, Schmidt, 'Multiple Chan
nel Per Bur-8tτDMA Multip
le Transponder Netvrork'
) is briefly mentioned. However, the carrier hopping method described in these patents does not require the location of various bursts on a TDMA frame, the station transmitting those bursts, or the position of the burst or time slot within it that the station should receive. is the burst time plan (
BurstTime Plan: Hereafter referred to as BTP)
It is assumed that in the same way that it is fixedly determined in a set of data called , it is also fixedly determined which carrier wave to receive from. It is necessary to change only a part of the BTP from time to time as in the separately filed patent mentioned above.

A normal TDMA device is capable of holding two sets of DTP data in case the DTP is changed, and it is possible to switch and use these at any time. Therefore, if a temporary change in hopping control is made only at one location on the TDMA frame under certain conditions, then
Even with conventional devices, it is possible to apply the method of the separately filed application.

However, there may be cases where it is desired to partially change the hopping control at any time for completely different reasons.

This will be explained with reference to FIGS. 4 and 5.

FIG. 4 shows the case where a portion of the TDMA frame is used in broadcast mode. One of the major features of satellite communications is that broadcast mode transmission is easy. If multiple stations use broadcast mode, teleconferences using conference mode are possible.

That is, in FIG. 4, burst 5 is used in the conference mode and is transmitted by a station participating in the p1 conference, for example, either AlB or C. One of the A, B, and C stations is the chair station, and the conference progresses by deciding from time to time which station will transmit burst 5. Since the chairman station only manages burst 5, there is no need for a reference station. In normal operation, the three stations A and BXC always receive burst 5, and transmit burst 5 with permission from the chairman station as necessary. Therefore, the burst 5 is mainly used for alternating transmission of signals such as images and facsimiles, and conversations during a conference are carried out continuously using a two-way link using normal bursts.

FIG. 5 shows a case where such a conference mode is performed in a system using a plurality of carrier waves. Each number in FIG. 5 is the same as in FIG. 2. Assume that three stations A, B, and C are currently holding a conference, and station A transmits an image signal using burst 6, and both stations B and C receive this. That is, the BXC station performs carrier hopping so as to receive fa in both time slots (broadcast mode time slots) in which burst 6 exists.

In this conference, when the next station B wants to speak and transmit an image signal, there are two methods.

One is a method in which station B transmits burst 6 at f& in a broadcasting time slot predetermined in BTP, and in this case, reception by stations A, B, and C remains the same as before. The other one is transmitted by station B using fb, and AlB
, Station C changes its hopping control at any time to receive fb in the broadcast mode time slot. The former method seems easy at first glance because it does not change the hopping control, but with Jin's method, conferences can only be held between AlB and 03 stations. For example, while stations A and B are holding a conference using burst 6, station C cannot hold another conference with station D using burst 7. No broadcast mode time slots will be available.

The ability to change carrier hopping control at any time in a particular time slot on a TDMA frame solves this problem. In this case, either of the above two methods may be applied, but if the transmitting side performs hopping control and is able to specify a carrier wave that does not actually exist, such as fz, the same burst time plan (DTP ) can also be used to control transmission. In other words, transmitting using fz corresponds to stopping transmission.

FIG. 6 shows an example of the configuration of an earth station having a carrier hopping function using transponder hopping, with four carrier waves fa and fb on both the transmitting and receiving sides.

A case is shown in which a hopping function is provided for fe, fd, FaXFb, and FcXFd.

The traffic power 150 from the terrestrial line is connected to a multiplex control circuit (
MUX) 202 is combined into a time division multiplexed format and output in a burst form in response to a timing signal 254 sent from a transmission timing control circuit 204 and applied to a modulator 206. In the TDMA system, modulation is usually 4-phase PSK (
Quadruture Phase 5hift Ke
ying: QPSK) is used. The modulator output has an intermediate frequency of 70 MHz or 140 MHz (
IF) band signal, high pre, de circuit 208.20
8' and is supplied to an upconverter 212 via a diode switch 210. Four upconverters are prepared corresponding to the four carrier waves, respectively with link frequencies fa, fb, fc and fd.
has an output of

The outputs of the converter 212 are combined into one RF output by a combiner 214, passed through a high power amplifier 216, and then transmitted from an antenna 242 to the satellite.

Transmission timing control circuit (hereinafter referred to as T, TMG) 20
4 also sends a control signal to switch control circuit '218 to control diode switch 210. For example, the transmission timing control circuit 204 divides the inside of the TDMA 7 frame into several time slots, and each time slot has two
A bit control signal is generated and sent to switch control circuit 218. The switch control circuit 218 decodes this signal, turns on only one of the four diode switches corresponding to the decoded contents 0 to 3, and converts the IF band signal output present in that time slot to the corresponding up-converter. supply to. That is, such a combination of the diode switch and the control device allows the output of the high power amplifier 216 to hop between the four frequencies faXfbXfc and fd.

The signals received from the satellite undergo frequency conversion on the satellite, so fa, fb, fc and fd on the transmitting side
The frequencies of are converted to Fa, Fb, Fc and Fd, respectively. These five signals pass through a low-noise amplifier 236, are branched by a distributor 234, are supplied to four down converters 232 corresponding to four carrier waves, and are converted into IF band signals. Each IF output is connected to a diode switch 230, a hybrid circuit 228', 2
28 and is supplied to the demodulator 226, but in this process, just like on the transmitting side, only one of the four diode suites 23'0 is turned on by the reception timing control circuit 224 and the switch control circuit 238. Since hopping control is performed in the same way, the first IF band signal is selected for one time slot.

The output of the demodulator 226 is sent to the separation control circuit 222 as a timing signal 264 from the reception timing control circuit 224.
A necessary output signal 151 is separated by control and output to the terrestrial line.

The aforementioned reception timing control circuit 224 receives a reference burst sent from a reference station and performs frame synchronization to establish a time reference for TDMA frames and multiframes.

That is, it is possible to generate timing signals for identifying various signals received arranged on a TDMA frame.

The synchronization control circuit 240 is supplied with a signal identifying the reception position of the synchronization burst transmitted by its own station from the reception timing control circuit 224, compares this with the position of the actually received burst, and calculates the difference, that is, the transmission timing. The error in the transmission timing control circuit 204 is detected and the operation of the transmission timing control circuit 204 is controlled to establish and maintain burst synchronization.

Although FIG. 6 shows a configuration in which the transmitting side and the receiving side have similar carrier hopping functions, in general, interconnectivity between the earth station and the transbosider is satisfied if only one side is provided.

FIG. 7 shows an example of a conventional control circuit corresponding to part of the reception timing control circuit 22□4 and switch control circuit 238 in FIG.

In the figure, a binary stage counter 302 counts symbol blocks 350, while the contents of the bits of the counter 302 are monitored by a decoder 304, and when they match, a reset signal 352 is generated and the counter 302
Reset the contents to 1000...000#. As a result, counter 302 has a period determined by decoder 1304. This period is chosen as the period of the TDMA frame.

On the other hand, when the basic burst is received, the frame synchronization signal contained therein is detected and applied as a detection pulse 354 to the preset terminal of the counter 302, and is applied to the preset terminal of the counter 302, as set in the register or manual digital switch 306. Bit data (DATAI) to counter 3
Load into 02. This data corresponds to the position of the base burst on the frame.

As a result, the counter 302 becomes K when it moves in the TDMA frame period and in synchronization with the received frame synchronization signal. This is a state in which frame synchronization is established, and the contents of counter 302 can be compared one-to-one with the phase within the TDMA frame. Here, the phase is
It means the relative position on the time axis in each TDMA frame.

Information regarding a large number of events is stored in a random access memory circuit (hereinafter referred to as RAM) 308 in order to process various received signals according to the phase on the TDMA frame.
recorded in

These event information consists of two types of information: control information indicating the content of the control and timing information indicating the phase on the control frame.
It is a collection of words consisting of two elements, arranged in the order of timing, and appears in the output under the control of the address counter 31o.

The timing information is still bits and comparator 312
It is compared with the contents of counter 302 at step . Further, the control information of the same word is added to the decoder...314, and the content of the control is output.

When the timing information output from the RAM 308 and the contents of the counter 302 match, the comparator 312 generates a match pulse 356 which is applied to the AND gates 316, 316'...
A timing signal 358 or 358' is supplied to necessary circuits from the gate that matches the output of the decoder 314.

- The Ik family 356 also has an address counter 310
It is also used as a clock signal for address counter 3.
Since the contents of 10 are advanced by one, the next word appears in the output of RAM 308 as a result. address counter 31
0 is the reset signal output 352Kj of the decoder 1304!
! Since it is reset to 7ki 0', as the contents of the counter 302 progress, the AND gates 316, 316', . . .
The control signals necessary for processing the received signal on the TDMA frame are successively obtained at the correct timing.

Switch control for setting and performing second bonder O hopping is performed using the code HOP included in part of the above-mentioned control information.

For example, in order to select one wave from four carrier waves as shown in FIG. 6, a 2-bit code is used, and this code is sent to the switch control circuit 238 in FIG. 6, and is decoded to generate a control signal for each switch. 266 can be made.

However, in such a method, the selection of a carrier wave is fixed for each event, so it is not possible to change the hopping control of some time slots on a frame at any time. In order to realize the present invention, as described above, two types of word sets that differ only in part are prepared, two types of RAM 308 are also prepared and recorded in each, and these are switched and used at any time.

(Objective of the Invention) The present invention is intended to realize a carrier wave control device capable of solving various problems as described above.

The present invention expresses the contents of various controls (events) added in advance on a JTDMA frame by DTP with corresponding codes (control information), summarizes this in the form of words for each event, and In a known control device that is arranged in the order of occurrence and stored in a memory circuit and read out sequentially for use in control, the control information includes a code for selecting a carrier wave related to the event, and whether the selection is fixed. A control code indicating whether the carrier wave is variable is included, and a code for a carrier wave to be selected under specific conditions is separately prepared, and when the above-mentioned specific conditions are met,
The above object is achieved by switching the carrier selection code for an event in which the control code indicates that carrier selection is variable to the separately prepared code.

In the present invention, if mutually distinguishable control codes are used for different time slots on a TDMA frame, each time slot can be distinguished from the other.

It is now possible to perform different controls depending on the port, and it is possible to change the reference station and control multiple conference modes completely independently.
The above objectives can be achieved.

(Structure of the Invention) In order to achieve the above object, the present invention has the following structure.

That is, in TDMA satellite communication in which the timing at which various events should occur is predetermined on a frame, the present invention arranges words containing control information indicating the content of the event corresponding to each of the events in the order of their occurrence. and a counter means that counts symbol fail signals and is reset at the cycle of the TDMA frame, and when the contents of the counter means coincide with the predetermined timing, the contents are stored in the storage means. A device that performs necessary control according to control information included in a word corresponding to an event, which is selected from among the control information of the word in the storage means, the carrier wave to which the event is related. and a control code indicating whether the selection is fixed or variable, the carrier to be selected under certain conditions by a specific event indicating that the control code is variable. a carrier wave selection code storing means that stores a code corresponding to the carrier wave selection code separately from the storage means; and a signal indicating the existence of the control code and the specific condition when the specific condition is satisfied. The carrier wave selection code for a specific event indicating that the code is variable is configured to include means for switching from a carrier wave selection code in the storage means to a code in the carrier wave selection code holding means. .

Further, the carrier wave selection code holding means includes a plurality of carrier wave selection codes corresponding to one control code, and has a selection means for selecting which carrier wave selection code is to be output based on a second condition. You can also do it.

(Example of the invention) Embodiments of the present invention will be described below based on the drawings.

FIG. 8 shows a control circuit of the present invention corresponding to FIG. 7, and corresponding blocks are given the same symbols as in FIG.

In the present invention, the code HOP representing the carrier wave to be selected as described above is included in the control information of the word representing one event.
In addition, a control code C indicating whether the selection of item 7 is fixed or variable is included. For example, in the application to reference station switching, the time slot in which the reference burst is present is usually coded to select the carrier Fa (HOP (
Fa)) is recorded, but the control code C indicates that it is "variable". Here "variable" is %lN
Suppose that it is expressed as .

On the other hand, a code HOP(Fb) for selecting a carrier wave Fb that can receive the preliminary reference burst is held in a register or manual digital switch 324.

HOP(Fa) in RAM 308 and HOP(Fb) in register 324 are supplied to data selector 326, but signal 3 indicating loss of reference burst
When 63 occurs, it is added to the AND gate 328, and the logical product with the information of the control code C is taken, and the data selector 3
26.

As a result, HOP (Fb) can be selected as the carrier wave selection code only in the time slot where the reference burst exists. The output of the data selector 326 is latched in synchronization with the coincidence pulse 356 in a latch circuit 330 and appears as an output. This output is sent to a decoder I239 corresponding to the switch control circuit 238 in FIG.
6 and is used to control which carrier wave is selected.

FIG. 9 shows another embodiment in which the present invention is applied to a control circuit of a different type from that shown in FIG. In the figure, if we first look at the part of the known technology, a binary stage counter 302' counts symbol clocks 350, and the contents are stored in the decoder 1.
It is the same as in FIG. 8 in that it is monitored by a signal 304 and operates at a frame period by a reset signal 352. However, in the TDMA system in which this circuit is used, the phase on a frame is largely quantized in units of 2L symbols. That is, various events on a frame occur only at intervals of at least 2L symbols or an integral multiple of seven. As a result, the TDMA 7 frame is divided into a maximum of 2 (IC-L) units, so it is only necessary to define what kind of control should be performed on each unit of the various control lines on the TDMA frame. Therefore, there is no need to include timing information in the word held in the RAM 308 (the contents of the -L digit can be directly added to the upper part of the counter 302' to the address terminal of the RAM 308).

On the other hand, the contents of the lower digits of the counter 302' are determined by the decoder ■3.
05 and defines the specific timing within the unit with symbol clock precision.
is generated and determines the timing of control execution.

A control circuit of this type is disclosed in US Pat. No. 4,298,979 (T, R., published on November 3, 1981).

Dobyn+set, al, kiDecodlng
TIM Bus 5truc-turs'). However, such a known control circuit cannot change carrier hopping at any time.

Application of the invention in the circuit of FIG. 9 is as follows.

First, the control code C has P bits, resulting in a maximum of 2P-
One time slot is identified.

If all of the P bits are SI O//, this indicates that the carrier selection code HOP is fixed. The control code is converted into a maximum of 2F-1 time slot designation signals by the decoder 327 (and goo) 328.328',...
・Display signal 363.363' of specific conditions corresponding to
,... and the result is OR gate 32
9, and gate 328.328',
. . , when the logical product becomes town I, the data selector 326 is controlled to switch the output of 7 from the HOP output of the RAM 308 to the HOP output of the register 324'. The register 324' is equivalent to a small-capacity RAM, holds a maximum of 2P-1 carrier wave selection codes HOP, and outputs the corresponding carrier wave selection code using the P-bit control code C as an address.

As another embodiment of the present invention, a plurality of carrier selection codes HOP can be stored externally corresponding to one control code C. In this case, which HOP to use depends on the second
Depending on the conditions. This feature allows you to receive different carriers in a particular time slot, e.g. receive one carrier during one multiframe, or n frames, and receive another carrier during the next multiframe. It is effective for applications such as periodically receiving and monitoring bursts sent using the .

(Effects of the Invention) According to the present invention, hopping control can be changed at any time in this way, and the base station switching system, which is the original purpose, can be easily improved.

Furthermore, in order to realize a 1' DMA system that can operate in conference mode, it is possible to operate in several broadcast modes and conference modes by increasing the number of time slots that can be used with the control code shown in Figure 8. Operation and use can be controlled independently. That is, there are methods such as arranging control codes as many times as the number of time slots to be independently controlled, or using binary representation. In this case, the register 324 must also be able to record a carrier selection code corresponding to the number of time slots to be independently controlled.

Furthermore, it goes without saying that the circuit of the present invention can be used not only on the receiving side but also on the transmitting side.

As described above, the present invention can be applied to various known control circuits, and as a result, it has great effects in improving the reliability of TDMA satellite communications and expanding the range of application.

[Brief explanation of the drawing]

Fig. 1 is an illustration of a TDMA system using a single carrier wave. Fig. 2 is an illustration of a TDMA system using multiple carrier waves. Fig. 3 is an illustration of a TDMA system using a reference burst and a synchronization burst.
Frame configuration diagram Figure 4 is an explanatory diagram when part of the TDMA 7 frame is used in broadcast mode. Figure 5 is an explanatory diagram of conference mode performed in a system using multiple carrier waves. Figure 6 is a carrier wave hopping function. FIG. 7 is an example of a conventional control circuit; FIG. 8 is an example of a control circuit to which the present invention is applied. FIG. 9 is another implementation of the control circuit to which the present invention is applied. Give an example. 1,! ',,1''...Burst from station A, 2.2'
. 2″...Burst from station B, 3. 3', 3''・
...Parse from station 0), 4. 4', 4'...Burst from D station, 5,6.7...Broadcast mode time slot burst, 10.10', 10'...A synchronization signal, 11...Reference Burst, 20... Synchronization signal of B station, 21... Synchronization burst of B station, 30...
Synchronization signal of 0 station, 31... Synchronization burst of 0 station, 40
... Synchronization signal of D station, 41 ... Synchronization burst of D station, 150 ... Traffic input, 151 ... Output signal, 202 ... Multiplex control circuit, 204 ... Transmission timing control circuit, 206...Modulator, 208, 208'
...Hybrid circuit, 21O... Diode switch, 212... Up converter, 214... Combiner, 216... Large power amplifier, 218... Switch. Child control circuit, 222... Separation control circuit, 224...
Reception timing control circuit, 226... demodulator, 228
．． 228'...Hybrid, de-circuit, 232...Down converter, 234...Distributor, 236...Low noise! Width gauge, 238...Switch control circuit, 239...
・Decoder 1.240...Synchronization control circuit, 242...
・Antenna, 254...Timing signal, 264...
- Timing signal, 266... Control signal for each switch, 302, 302'... Counter, 304... Decoder 1, 305... Decoder IV, 306... Register or manual digital switch, 3o8...・RAM,
31G...Address counter, 312...Comparator,
314...Decoder head, 316, 316'316#.
...And gate, 324, 324'...Register,
326...Data selector, 327...Decoder V
, 328.328'...and gate, 329...
330...U, circuit, 35o...Symbol black, 352...Reset signal, 354...
...detection pulse, 356...coincidence pulse, 357...
・Timing pulse, 358, 358'... Timing signal, 363, 363'... Display signal of specific conditions (
For example, standard burst loss signal) Attorney Yawata
Yoshi Hiroki Figure 1 Figure 2 (A) FA Fa Fd Fc -1- Shima

Claims (2)

[Claims] (1) In TDMA satellite communication, where the timing at which various events should occur is predetermined on the frame, words containing control information indicating the content of the event are arranged and stored in the order of occurrence corresponding to each of the events. and a counter means that counts the symbol clock signal and is reset at the cycle of the TDMA frame, and the content of the counter means is retained in the storage means when the content of the counter means coincides with the predetermined timing. A device for performing necessary control according to control information included in a word corresponding to an event, wherein the control information in the word in the storage means includes a code for selecting a carrier wave related to the event, and a code for selecting a carrier wave to which the event relates, and a code for selecting a carrier wave to which the event relates, and a control code indicating whether the control code is fixed or variable; and a specific event indicating that the control code is variable includes a code corresponding to a carrier wave to be selected under specific conditions. the control code is variable by a carrier selection code generating means that is generated separately from the storage means; and a signal that indicates the existence of the control code and the specific condition when the specific condition is met. A carrier wave hopping control for TDMA satellite communication, characterized in that the carrier wave hopping control for TDMA satellite communication is characterized in that it has means for switching a carrier wave selection code for a specific event indicating that a carrier wave is selected from a carrier wave selection code in the storage means to a code of the carrier wave selection code generation means. Device. (2) The carrier wave selection code generating means is capable of generating a plurality of carrier wave selection codes corresponding to one control code, and the carrier wave selection code generating means is capable of generating a plurality of carrier wave selection codes in response to one control code, and a second
The carrier hopping control device for TDMA satellite communication according to claim 1, further comprising a selection means for selecting according to conditions.