JPH0424899B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a random access transmission device that coexists with a distributed processing type adaptive time division multiplex transmission device.

In a traditional communication line network, a switching function for interconnecting lines and a multiplex transmission function for connecting each switching function existed clearly separately. In such a situation, mutual communication begins only after an exclusive communication line is established between the terminals desiring connection. That is, a line setting procedure (call processing) is always required prior to communication. If the information sent and received between terminals is telephone voice, fax, file transmission, etc., and the transmitted information is regularly and continuously transmitted for a considerable period of time, this call processing will not reduce the transmission efficiency. .

In recent years, in the information processing field, there has been a growing trend toward distributed processing based on computer networks, and there has been a demand for efficient data transmission between computers or between terminals and computers, which occurs aperiodically. Conventionally, this problem has been dealt with by preparing a random access network exclusively for computer networks. However, society's expectations for data communications cannot be satisfied by the proliferation of these exclusive and individual networks, and a new transmission medium that can organically and flexibly integrate and accommodate each network is needed. It will be explored. Since such transmission media are strongly required to have wide-area and general-purpose characteristics from an economical point of view, they are not compatible with traditional circuit-switched signals that dislike delays between transmission and reception and have poor delay correction and absorption functions. coexistence is expected.

As a way to satisfy the above contradictory demands,
It is conceivable to treat signals suitable for circuit switching, such as voice, with priority, and to process non-periodically generated data using random access technology, making use of regularly occurring idle time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a periodic signal priority type random access transmitter that embodies the related new transmission medium.

This invention includes a periodic signal sending station that sends out its own burst signal for each arbitrary frame using a time slot arbitrarily selected by each station based on a frame having J time slots, and a periodic signal sending station that sends out its own burst signal for each arbitrary frame; In a time-division transmission system that includes a non-periodic signal sending station that sends out its own signal at any time without interfering with ; Observe the time slot monitor output at all permissible transmission timings for each of the J time slots, and determine whether the transmission timing is unused, used periodically, or used aperiodically. and an access control circuit that transmits the aperiodic signal burst using a time slot other than the periodically used transmission timing. It is a prioritized random access transmitter.

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1a shows a transmission signal time series of a conventionally used time division multiple access (TDMA) system. In the figure, the same transmission signal pattern is repeated in units of one fixed frame indicated by Tf. That is, each station A and B periodically sends out its own burst signal to the same position in the frame.

FIG. 1b shows a burst of a multi-period TDMA signal. The signal of station A transmits its own burst every frame as in FIG. 1a, but stations B and C transmit their own burst every two frames. In other words, stations B and C transmit their own bursts at twice the frequency of station A.
In general, it is possible to send out a self-burst every n frames, and it is possible to send out a self-burst to station A at a cycle n times as many. In this case, by observing only a few frames, it appears that the time slots are used at irregular intervals, but it is very easy to identify whether or not the time slots are used periodically.

Figure 2 shows the usage status of the six time slots in a frame as shown in Figure 1b, simply calculated by averaging for each frame.The first time slot 1 is transmitted by station A every frame. Therefore, the average value is 1, and slots 3 and 4 show an average value of 0.5 because stations B and C transmit every two frames. Although such simple averaging shows that the first time slot with an average of 1 is used every time, it is unclear how the third and fourth time slots are used. In order to solve this problem, a reference signal as shown in FIG. 3 is used.

The reference signal 7 in FIG. 3 becomes 1 in odd frames. The waveform and reference signal 8 are waveforms that become 1 in even frames.

When the reference signal 7 is applied to the frame signal of FIG. 1b and the fourth time slot (burst of station C) is observed, it is immediately clear from FIG. 4a that it is unused in this period. Similarly, reference signal 8 is
If the third time slot (burst of station B) is observed after multiplying the frame signal in FIG. 4b, it can be similarly seen from FIG. 4b that it is unused in this period. Also, the usage status of each time slot only when the reference signal is 1 (1 when used, 0 when not used)
If a burst with the same period as the reference signal appears in a certain time slot, the average output will always be 1. This means that the reference signal equal to the transmission period as shown in Figure 3 will be equal to 1. By comparing the time slot and the received signal, it can be determined whether each time slot is empty or in use in that transmission period. When the previous average output takes a value between 0 and 1, it is known that it is the beginning or end of a periodic signal, or the reception of a random periodic signal.

FIG. 5 is a diagram showing actually necessary reference signal groups. In the figure, 40 is for every frame period, 41, 4
2 is the same as reference signals 7 and 8 in Fig. 3, 43, 4
4 and 45 are reference signals for 3 frame periods,
Each changes upward with a frame period Tf.

FIG. 6 is a block diagram of an embodiment of a time slot monitor 60 that detects the presence or absence of a signal on each time slot, and a transmission timing detector 61 that detects the period in which each time slot is used. FIG.

A received signal is applied from the input terminal 100, and the presence or absence of the signal on the time slot is determined by the input power detector 600. This identification value is input to the shift register 601 one after another in time slot cycles, and
After this operation is completed for one frame, the usage status of each time slot can be observed individually through the changeover switch of the time slot sweeper 602 according to the contents of the shift register 601.

Sending timing detection for an arbitrary time slot is performed using a reference signal generator 6100 that generates a reference signal shown in FIG. 6, a switch 6101 that allows the output of the time slot sweeper 602 to pass only when the output is 1, and This is done by a smoothing circuit (low-frequency filter) 6102 that averages the output of , and a discriminator 6103 that uses three values to identify whether the output of the circuit is zero, 1, or an intermediate value. The same blocks as block 610 are prepared only for the types of reference signals, and are composed of the same components except that the waveforms generated by the reference signal generators of each block are different. When each output of the output terminal 101 is 1, it indicates that the sending cycle is used periodically, and when it is 0, it indicates that it is not used.

Note that in order to monitor all time slots at the same time, a send timing detector 61 may be provided for each time slot, or each smoother (low frequency filter) 6102 in the block 610 may be prepared for the number of time slots. , time-divisionally switched in synchronization with the time slot sweeper 602, and the smoother 6102
It is necessary to read out the identification values for the time slots one after another within the time that the time slots are connected to the discriminator 6103.

FIG. 7 is a diagram showing a block diagram of one embodiment of the present invention.

In the figure, 80 is an antenna, and 90 is a circulator for branching input and output to the antenna.
60 is a time slot monitor, and 61 is a sending timing detector, each of which is the same as in FIG.
Reference numeral 70 denotes an access control circuit, and transmission data is stored in a buffer memory 701 from an input terminal 102, and sent to the output of a transmission timing oscillator 702 which generates a transmission timing signal corresponding to an empty timing detected by a transmission timing detector 61. Accordingly, it is read out and fed to the converter.

As described above, according to the present invention, not only the conventional TDMA system that sends out its own burst every frame, but also the multi-period TDMA that allows bursts to be sent every n frames, each station independently determines the empty sending timing. can be detected and aperiodic signals can be sent out without interfering with periodic signals.

According to the access control procedure proposed in the present invention, since priority is given to periodic signals, there is a possibility that all time slots will be occupied by the same signal. For this reason, this inconvenience can be eliminated by dedicating a fixed transmission cycle to non-periodic signals.

In addition, since there is a possibility that the periodic signal is not recognized as a periodic signal by other stations at the time when the information transmission starts or ends, the transmission signals at both ends are expected to receive disturbances, and after stabilizing, the call is set up. must be completed.

[Brief explanation of drawings]

FIG. 1a is a diagram illustrating a frame structure used in conventional time division multiplex transmission. FIG. 1b is a diagram illustrating a frame structure used in multi-period time division multiplex transmission that allows burst transmission every n frames. Second
The figure is a conceptual diagram obtained by simply averaging the usage status of each time slot in the frame of Figure 1b, and Figure 3 is used to observe the usage status of time slots divided into odd and even frames. The figure which shows the example of a reference signal. 4a and 4b are diagrams showing how the time slot usage status of the time division multiplexed transmission signal of FIG. 1b is observed divided into odd and even frames using the reference signal of FIG. 3; FIG. FIG. 5 is a diagram showing an example of a general reference signal. FIG. 6 is a diagram showing a block diagram of a time slot monitor and a sending timing detector. In the figure, 60 is a time slot monitor, and 61 is a sending timing detector. FIG. 7 is a diagram showing a block diagram of an embodiment of the present invention. In the figure, 60 is a time slot monitor, 61 is a sending timing detector, and 70 is an access control circuit.

Claims (1)

[Claims] 1 Using time slots arbitrarily selected by each station based on a frame with J time slots,
A time division transmission system in which a periodic signal sending station that sends out its own burst signal every arbitrary frame and an aperiodic signal sending station that sends out its own signal at any time without interfering with the signal of the periodic signal sending station coexist. a time slot monitor that detects the presence or absence of a signal on each time slot in the received frame signal; and a time slot monitor that monitors the output of the time slot monitor at all permissible transmission timings for each of the J time slots. , a send-out timing detector that detects whether the send-out timing is unused, used periodically, or used non-periodically; and a time slot other than the send-out timing that is used periodically; What is claimed is: 1. A periodic signal priority type random access transmitting device, comprising: an access control circuit that transmits a non-periodic signal burst using;