JPH0439816B2 - - 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 endpoints that wish to connect. 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 terminal 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 communication are limited to these exclusive,
A proliferation of individual networks will not be satisfied after all, and new transmission media will be sought that can organically and flexibly integrate and accommodate each network. Since such transmission media are strongly required to have wide-area and general-purpose characteristics from an economic standpoint, 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 transmitting station that transmits 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; A time slot monitor that detects the presence or absence of a signal on each time slot in a received frame signal 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 the signal. For each of the J time slots, observe the time slot monitor output at multiple transmission timings with the longest period that do not share a common time slot, and calculate the usage rate of each transmission timing within a certain observation period. A transmission timing usage rate detector that detects the non-periodic signal burst of the own station by preferentially using the transmission timing with a higher usage rate among the transmission timings used with usage rates within a certain non-zero range. A periodic signal priority type random access transmitting device is characterized in that it is equipped with an access control circuit for transmitting a This is a periodic signal priority type random access transmitter equipped with an access control circuit that has an added function of transmitting its own station's aperiodic signal bursts using transmission timing with a usage rate of zero in the order in which the signals are transmitted.

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 fixed frames indicated by T _f . 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 each time slot is used at irregular intervals, but it is extremely 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, which is simply averaged for each frame based on Figure 1b.
Since station A transmits every frame, the average value is 1,
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 has a waveform that becomes 1 during odd frames, and the reference signal 8 has a waveform that becomes 1 during 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 it by the frame signal of FIG. 4b, it can be similarly seen from FIG. Also, when the usage status of each time slot is averaged 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 is always 1. This allows each time slot to be
You can tell whether it is empty or in use at that transmission cycle. 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, 42
are the same as reference signals 7 and 8 in FIG. 3, 43, 44,
45 is a reference signal for three frame periods, each of which changes downward at a frame period T _f .

FIG. 6 shows the elements constituting the present invention: a time slot monitor 60 that detects the presence or absence of a signal on each time slot, and a transmission timing usage rate detector that detects the period in which each time slot is used. 6 is a diagram showing a block diagram of an embodiment of the device 61. FIG.

A received signal is applied from an input terminal 100, and an input power detector 600 identifies the presence or absence of a signal on a time slot. This identification value is input to the shift register 601 one after another at a time slot period, and
After this operation has been completed for a frame, the contents of shift register 601 can be observed individually through the toggle switch of each time slot sweeper 602.

Detection of the transmission timing usage rate for an arbitrary time slot is performed by a reference signal generator 6100 that generates the 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, This is performed by a smoothing circuit (wavelength reducer) 6102 that averages the output of the switch. Blocks 611 to 615, which are the same blocks as block 610, are provided with only the necessary types of reference signals including block 610, and are composed of the same components except that the waveforms generated by the reference signal generators of each block are different.

At this time, the prepared reference signals are selected from a plurality of reference signals having the longest period and not having the same transmission time in common so that the usage rate of the transmission timing to be observed can be measured independently. For example, in Figure 5, 1, 2, 3
Although the timing of transmitting once per frame is clearly specified, transmitting once every six frames, which is the least common multiple of these, is the longest cycle. Practically speaking, it is convenient to limit the transmission to once every 2 ⁱ (i≦n) frames, and in this case, the longest cycle is 2 ⁿ frames. Output terminal 101
Each output directly corresponds to the usage rate of that sending timing.

In order to monitor all time slots at the same time, a transmit timing usage rate detector 61 may be provided for each time slot, or each smoother (low frequency filter) 6102 in block 610 may be prepared for the number of time slots. Then, the time slot sweeper 60
It is necessary to time-divisionally switch in synchronization with 2.
In the sense of not interfering with periodic signals, all transmission timings that are not used periodically can be used by non-periodic signal transmission stations. But if you do it like this,
All empty transmission timings are occupied by non-periodic signal transmission stations with a low utilization rate, resulting in an unreasonable situation in which no new periodic signals can enter.

In the present invention, in consideration of this point, the aperiodic signal sending station does not allow careless access to empty sending timings, and first, the non-periodic signal sending station does not allow inadvertent access to empty sending timings, and first, it does not allow inadvertent access to empty sending timings. requires sending out a self-burst. Only when the usage rates of the non-periodically used transmission timings are all above a certain value, access is newly permitted within the empty transmission timing.

By establishing regulations regarding aperiodic signal transmission as described above, it is possible to prevent the occurrence of unreasonable phenomena such as those described above, and aperiodic signal transmission stations can form groups and participate in several transmission timings. As a result, an empty time slot is secured so that a new periodic signal sending station can enter.

Furthermore, if there is no transmission timing that is used with a usage rate within a certain range, there is a possibility that the full-air transmission timing will be used by non-periodic signal bursts with a low usage rate, even temporarily. In order to prevent this, in such a case, the non-periodic signal bursts of the own station are transmitted in a predetermined order using transmission timings with a usage rate of zero. This eliminates the concerns mentioned above.

FIG. 7 is a block diagram of an embodiment of the present invention based on this convention.

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 transmission timing usage rate detector, each of which is the same as in FIG. Reference numeral 70 denotes an access control circuit, and data to be sent is sent from the input terminal 102 to the buffer memory 7.
It is stored in 01. Send timing oscillator 702
extracts one sending timing operating within a certain usage rate range based on the output of the sending timing usage rate detector 61, and generates the same sending timing signal.
Send data in buffer memory 701 is read out in response to this send timing signal output and is supplied to modulator 700.

As described above, according to the present invention, signals suitable for circuit switching, such as voice signals, are treated preferentially, and non-periodically generated data is processed using random access technology by using regularly occurring idle time. Through this processing, it becomes possible to organically, broadly and flexibly integrate small-capacity data communication networks, while also making it possible to rationally coexist with traditional circuit-switched signals that are sensitive to delays between transmission and reception.

[Brief explanation of drawings]

Figure 1a is a diagram explaining a frame structure used in conventional time division multiplex transmission, and Figure 1b is a diagram explaining a frame structure used in multi-period time division multiplex transmission that allows burst transmission every n frames. , second
The figure is a diagram obtained by simply averaging the usage status of each time slot in the frame of Figure 1b, and Figure 3 shows the usage status of time slots of odd numbers,
Figure 4a is a diagram showing an example of a reference signal used for observation divided into even frames. Figure 4a shows the usage status of the time slot of the time division multiplexed transmission signal in Figure 1b using the reference signal in Figure 3. Figure 4b is a diagram showing the observation divided into even frames, Figure 5 is a diagram to explain an example of a general reference signal, and Figure 6 is the use of time slot monitor and sending timing. Figure 7 showing the block diagram of the rate detector.
The figure shows a block diagram of an embodiment of the present invention. In the figure, 60 is a time slot monitor, 61 is a transmission timing usage rate detector, and 70 is an access control circuit.

Claims (1)

[Claims] 1. Interfering with the signal of a periodic signal sending station that sends its own burst signal every arbitrary frame using a time slot arbitrarily selected by each station based on a frame having J time slots. In a time-division transmission system that includes a non-periodic signal transmitting station that transmits its own signal at any time without transmitting signals, a time slot monitor detects the presence or absence of a signal on each time slot in the received frame signal. ; For each of the J time slots, observe the time slot monitor output at a plurality of transmission timings with the longest period that do not share a common time slot, and detect the usage rate of each transmission timing within a certain observation period. A transmitting timing usage rate detector that transmits the non-periodic signal burst of its own station by preferentially using the transmitting timing with a higher usage rate among the transmitting timings used with usage rates within a certain non-zero range. What is claimed is: 1. A periodic signal priority type random access transmitting device, comprising: an access control circuit that gives priority to periodic signals. 2 Added a function to send out aperiodic signal bursts of the own station using transmission timings with a usage rate of zero in a predetermined order if there is no transmission timing that is used with a usage rate within a certain range that is not zero. Claim 1 comprising an access control circuit
The periodic signal priority type random access transmitting device as described in .