JPH0439815B2 - - 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 it is important to develop a new transmission system that can organically and flexibly integrate and accommodate each network. A medium will be sought. Such a transmission medium is
Naturally, wide-area and general-purpose characteristics are strongly required from an economic standpoint, so it dislikes delays between transmission and reception, and is expected to coexist with traditional circuit-switched signals, which have poor delay correction and absorption functions. It's going to be a big deal.

One way to satisfy the above contradictory demands is to give priority to signals suitable for circuit switching, such as voice, and use regularly occurring idle time to randomly access non-periodically generated data. It is conceivable that this can be treated with technology.

An object of the present invention is to provide a periodic signal priority type random access transmitter/receiver that embodies such a new transmission medium. This invention is based on J times.
A periodic signal transmitting station that transmits its own burst signal every arbitrary frame using a time slot arbitrarily selected by each station based on a frame having a slot, and a periodic signal transmitting station that transmits its own burst signal for each arbitrary frame without interfering with the signal of the periodic signal transmitting station. In a time division transmission system in which aperiodic signal sending stations that send out their own signals at any time coexist, a time slot monitor that detects the presence or absence of a signal on each time slot in a received frame signal, and For each of the time slots, the time slot monitor output is observed at a plurality of transmission timings with the longest period that do not share a common time slot, and the usage rate of each transmission timing within a certain observation period is detected. Send out the non-periodic signal burst of the own station by using the send timing usage rate detector and preferentially use the send timing with the higher usage rate among the send timings that are used with the usage rate within a certain non-zero range. and an access control circuit that adaptively determines the usage rate within the certain range according to the usage frequency of all time slots, Access control with the added function of transmitting the own station's aperiodic signal bursts using 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. This is a periodic signal priority type random access transmitter equipped with a circuit.

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 at 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 transmit a self-burst every n frames, and it is possible to transmit a self-burst to the A station at n times the period. In this case, by observing just a few frames, it appears that each time slot is used at irregular intervals, but it is extremely easy to identify whether or not periodic time slots are used. .

Figure 2 shows the usage status of the six time slots in a frame, as shown in Figure 1b, simply averaged for each frame. Therefore, the average value is 1, and slots 3 and 4 show an average value of 0.5 because stations B and C send out every two frames.
In such a simple average, although it can be seen that the first time slot with an average of 1 is used every time, the 34th time slot
It is unclear how 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
After multiplying the frame signal in figure b, the third time signal is
When observing the slot (burst of B station), the 4th
From FIG. b, it can also be seen that it is unused in this cycle. Also, only when the reference signal is 1, the usage status of each time slot (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 allows us to determine whether each time slot is empty or in use in that transmission period by comparing the received signal with a reference signal equal to a certain transmission period as shown in Figure 3. I understand. When the previous average output takes a value between 0 and 1, it is known that it is at the beginning and end of a periodic signal or at the time of receiving 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 a system according to the present invention, which comprises 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 6 that detects in what cycle each time slot is used. FIG. 2 is a block diagram of one embodiment.

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 is completed for a 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.

Detection of the selected timing usage rate for an arbitrary time slot is performed by 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, This is done by a smoothing circuit (low frequency filter) 6102 that averages the output of the switch. Blocks 611 to 615, which are the same blocks as block 610, are the same blocks as block 610.
Only the types of reference signals needed are prepared, including the reference signal generators of each block, and the blocks are composed of the same components except for the waveforms generated by the reference signal generators of each block. At this time, the reference signals prepared include a plurality of wavelength cycles having no time slot in common so that the usage rate of the transmission timing to be observed can be measured independently.
For example, in the case of FIG. 5, the timing of transmitting once every 1st, 2nd, or 3rd frame is specified, but the longest cycle is once every 6 frames, which is the least common multiple of these. Practically speaking, 1 in 2 ⁱ (i≦n) frames.
It is convenient to limit the transmission to 2 n frames, and the maximum period in this case is 2 ⁿ frames.

Each output of the output terminal 101 directly corresponds to the usage rate of that transmission timing.

Note that in order to monitor all time slots at the same time, a selected timing usage rate detector 61 may be provided for each time slot, or a smoother (low frequency filter) 6102 in block 610 may be used for each time slot. As many slots as the number of slots are prepared, the smoother 6102 is switched in a time division manner in synchronization with the time slot sweeper 602, and the discrimination values for the time slots are determined one after another within the time that the smoother 6102 is connected to the discriminator 6103. It is necessary to read it. In the sense of not interfering with periodic signals, all transmission timings that are not used periodically can be used by non-periodic signal transmitters. However, if this is done, all the empty transmission timings will be occupied by non-periodic signal transmission stations with a low utilization rate, resulting in an unreasonable situation in which new periodic symbols cannot be accepted.

In the present invention, in consideration of this point, the aperiodic signal sending station does not allow careless access to the empty sending timing, and first, the non-periodic signal sending station does not allow careless access to the empty sending timing. 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 the rules regarding the transmission of aperiodic signals as described above, it is possible to prevent the occurrence of the above-mentioned unreasonable phenomena. That is, the non-periodic signal sending stations will form a group and participate in several sending timings, and an empty time slot will be secured so that a new periodic signal sending station can be accepted.

Furthermore, if there is no send timing that is used with a usage rate within a certain range, there is a risk that the all-empty send timing will be used, even temporarily, by an aperiodic signal burst with a low usage rate.

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. The narrower the usage rate range of transmission timings that aperiodic signals are required to use preferentially is set, the more convenient it is for the aperiodic signal transmission station, since it is possible to proceed to another empty transmission timing sooner. On the other hand, it is preferable to set this usage rate range widely so as not to be blocked by periodic signal sending stations. In order to find a compromise between the two, it is found that this usage rate range can be adaptively changed in accordance with the usage status of all time slots. In other words, when the entire time slot is not used very much, the usage rate range is narrowed to increase the degree of freedom of the non-periodic signal selection station, allowing for a different transmission timing, and vice versa. When the usage rate of the entire time slot increases due to traffic congestion, the usage rate range can be widened to suppress the degree of freedom of the non-periodic signal transmission station, making it easy to switch to a different transmission timing. This means that they will not be allowed to enter the country.

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 an input terminal 102 to a buffer memory 71.
It is stored in 0. Send timing oscillator 702
receives the output of the time slot monitor 60 from the input terminal 103, detects the usage rate of all time slots, determines the usage rate range of the transmission timing in which the aperiodic signal is required to be transmitted preferentially, Based on the sending timing usage rate detector 6
1 output, extracts the transmission timing to be used preferentially, and generates the same transmission timing signal.
The transmission data in buffer memory 701 is read out in accordance with this transmission 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 is 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 dislike delays between transmission and reception.

[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. FIG. 2 shows a simple average of the usage status of each time slot in the frame of FIG. 1b.
FIG. 3 is a diagram showing an example of a reference signal used to observe the usage status of time slots divided into odd and even frames. FIG. 4 is a diagram showing how the time slot usage 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. 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 send timing utilization rate detector. In the figure, 60 is a time slot monitor, and 61 is a transmission timing usage rate 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 transmission timing usage rate detector, and 70 is an access control circuit.

Claims (1)

[Claims] 1. A periodic signal transmitting station that transmits 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 in which a non-periodic signal transmitting station that transmits its own signal at any time without interfering with the signal of the signal transmitting station coexists, it is possible to check the presence or absence of a signal on each time slot in the received frame signal. For the time slot monitor to be detected and each of the J time slots, the output of the time slot monitor is observed at a plurality of transmission timings with the longest period that do not share a common time slot, and a fixed observation is performed. A transmission timing usage rate detector that detects the usage rate of each transmission timing within a period, and a transmission timing usage rate detector that detects the usage rate of each transmission timing within a period, and each transmission timing that is used with a usage rate within a certain range that is not zero.
Access control that sends its own station's aperiodic signal burst by preferentially using a transmission timing with a higher usage rate, and adaptively determines the usage rate within the certain range according to the usage frequency of all time slots. What is claimed is: 1. A periodic signal prioritizing random access transmitting device characterized by comprising a circuit. 2. The periodic signal priority type described in paragraph 1, which is equipped with an access control circuit that has an added function of transmitting its own station's aperiodic signal burst using a transmission timing that is used at a usage rate within a certain non-zero range. Random access transmitter.