JPH0936916A - Packet repeating system for radio transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system, with which reliability as a system can be secured even against a fault of device in the middle of repetition and further one carrier is enough for carrying radio signals, concerning a repeater system for radio signals to be applied when the distance between a lot of distributedly installed spots and a center for collecting information is larger than the limit of the propagating distance of radio signals. SOLUTION: Plural slave equipments 12 for making sensor information or supervisory and control information into packets and transmitting them to master equipment 11 installed at the center are connected by a linear transmission line, each slave equipment has the radio communication function of a semiduplex system and a function for storing/repeating data made into packets, and the installation interval of adjacent slave equipment is set shorter than the 1/2 arrival distance of radio signals so that the radio signal can over reach. A time slot phase related to the installation position is allocated to each piece of slave equipment, radio transmission can be performed just for this time width, this packet is repeated between the slave equipment like packet relay in time division manner and when a fault is generated at the adjacent slave equipment, the packet is repeated while skipping this slave equipment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet communication system using a wireless communication medium.
The present invention relates to a relay system in a wireless packet communication system.

[0002]

2. Description of the Related Art For example, when a center facility (hereinafter referred to as a base unit) collects sensor information or the like installed at a plurality of places in a tunnel at regular intervals,

[FIG. 7]

As illustrated in FIG. 8, generally, a cable or the like is stretched to form an information transmission path. However, with this method, when the tunnel excavation work is in progress, work to extend the communication cable ahead with the increase in the number of installed slaves to capture sensor information and transmit it to the center as the work progresses. Is also required, which speeds up excavation work and impairs construction efficiency. Similarly, there is a problem that the work of treating the communication cable is required even when the construction is removed. As a countermeasure to the above, a method of making wireless by utilizing wireless communication in the transmission path between the control slaves is considered.

[0003]

The conventional method has problems in the following two cases. (A) When combined with a wired transmission line (

[Fig. 9] Although the number of radios themselves is small, the control radio slave unit with a radio communication function and a plurality of sensors scattered in the vicinity are still partially connected by a cable or the like. Therefore, the effect obtained by eliminating the cable is significantly reduced. (B) When installing a radio at each location where sensors are installed (

[Fig. 10] In this case, the wiring work such as the cable between the sensor and the wireless slave device having the wireless communication function can be performed only at one place and the communication cable wiring can be omitted. The problem of (a) is solved.

On the other hand, however, an increase in the number of wireless devices causes the following problems in wireless communication technology. (A) If the maximum distance between wireless devices is longer than the wireless signal reach distance, it is necessary to newly install a relay device. (B) It is necessary to introduce technology for avoiding collision between carrier signals transmitted by each radio. The problem of (a) was dealt with by installing a repeater at a key point in the conventional method.
In this method, it is necessary to take a redundant configuration so that the failure of a repeater having a different configuration / function from other radios does not affect the operation of the entire system, and it is necessary to take reliability measures. But,
This causes a cost increase of the system, and there is a problem in economical efficiency. There were two ideas for the problem of (b).

One of them is a method of repeatedly using two or more carriers having no mutual interference between these relays in order to avoid collision of radio carriers. this is

As shown in FIG. 10, the carrier is changed from f1 to f2 by a repeater (R in the figure) installed at a key part of the wireless transmission path. However, since this method uses a plurality of wireless carriers, it is one of finite resources, and in recent years, radio wave allocation has become tight, which is a problem.

The other method is to introduce an algorithm that uses one carrier but arbitrates between the radios. The following is known as a typical method generally used as this algorithm. (1) Polling method (2) TDMA method (3) CSMA / CD method, is CSMA / CA method (4) Token passing method The above method (1) has a problem that the processing load of the master unit is concentrated. The method (2) is already applied in satellite communication or the like, and is effective when the wireless signals are scattered within a range that can reach all the wireless slave devices in one transmission of the wireless signal. However, when the master unit and the slave unit far from the master unit are separated from each other, the same problem as the problem pointed out in (a) above occurs as a method of connecting the relay units. The method (3) is a well-known technique in the field of wireless communication known as "wireless LAN". However, in the CSMA / CD system, when the spread spectrum system is adopted as the radio signal, it is difficult to easily realize the signal collision detection function by the carrier sense. Further, in CSMA / CA, when traffic is concentrated on a specific wireless device, there is no guarantee that the transmission right will be evenly distributed to other wireless devices. For this reason,
It is not an appropriate method for a system that collects sensor information and monitoring control information evenly from all wireless slave devices.
The method (4) has already been put into practical use as a standard method for a wired LAN, but when a wireless medium is used as the subject of the present invention, a token signal is generated due to a bit error that occurs during transmission. Is more likely to disappear. Moreover, the master unit is usually responsible for the function of monitoring and regenerating the disappearance of the token, but the token disappears by monitoring the token that disappears in the vicinity of the remote unit that the wireless signal does not reach in one span. Sometimes it is technically difficult to achieve a fast regeneration.

In addition to the above, a cellular system (especially in a small area) that operates in cooperation with a wired network when a wireless device is installed in a wide range where a wireless signal does not reach in one transmission Microcellular method is a known technology in public wireless telephone systems, but the use of wired cables, even if partially, makes it possible to achieve the economicization that was the background of the need for the present invention. It is clear that nothing can be done.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the drawbacks of the conventional method, and the purpose thereof is to provide a plurality of wireless devices which are geographically installed linearly. Configures a system that periodically sends sensor information and monitoring control information obtained by each input / output function to the parent device in the center. Under the geographical environment where a large number of wireless slave units are installed in a one-dimensional manner, only one wireless carrier is used, and even if a partial failure occurs in the wireless relay transmission line, It has been necessary to realize a relay system for a wireless packet communication system that can ensure reliability without failure and that can reduce the cost of the entire wireless communication path.

[0009]

[Means for Solving the Problem] In response to each of the problem items in the preceding paragraph, a system having the following as its essence was devised. (A) The installation interval between the radios is set to one half or less of the reception limit distance of the radio signals so that the radio signals are overreached to the radios separated by two or more spans. (B) Each wireless slave device has a function of packetizing the information obtained by its own input / output function into a data block of a certain length and transmitting it, and receiving packet data from other wireless devices, and retransmitting it as necessary. It has a packet relay function for sending. (C) As a method of avoiding collision of radio signals, a kind of time division method (abbreviated as TDM) is applied. However, regarding the method of allocating the timing of transmitting the radio signal, the order of the transmission timing is pre-assigned corresponding to the place where each radio is installed. Moreover, the direction in which the allocation order shifts is set in two ways depending on the required speed of relay transmission of information, that is, (a) when the parent machine collects information from each child machine (hereinafter In the above, this is referred to as the upstream mode or the information collection mode), the order in which the wireless signal transmission timing is shifted is the mode in which the wireless device is shifted in the upstream direction toward the direction in which the master unit is located. (B) On the contrary, when the master unit distributes information to each slave unit (hereinafter, this is referred to as the downlink mode or command mode), the order of shifting the wireless signal transmission timing is the highest from the master unit. The mode is to shift to the remote unit at the far end. Also, the switching between these two modes can be performed automatically or manually. The radio that transmits the first packet when this radio communication system starts up from the initialization state is assigned to one of the radios at both ends installed in a one-dimensional manner. In addition, in the upstream mode, the most downstream child device has the first transmission right at initialization. Further, after the initial start-up, until the mode is changed, the packet with the indication of "vacant" or "blocked" in the header portion is continuously transmitted at a certain fixed period. (D) The packet relay algorithm was devised as follows. That is, by checking the header part of a packet received from another radio, whether the packet is located upstream or downstream with respect to its own position, and whether the packet relay mode currently operating is up. The function to judge the relay operation of the packet is provided by the combination of the states of the directional mode and the downlink mode.

[0010]

As a result, a long distance that cannot be reached by a single transmission of a radio signal while repeating relays between the radios installed in a straight line as if the data packetized into a fixed length is relayed as a bucket relay. Until now, packet communication is possible without using a repeater specialized for specific functions,
Moreover, this wireless packet relay system does not lose its function unless a plurality of wireless devices on the relay path are geographically consecutively out of order.

[0011]

DETAILED DESCRIPTION OF THE INVENTION First of all,

The basic operation of the case of claim 1 will be described in order based on an embodiment. (A)

As shown in FIG. 1, it is assumed that N wireless communication devices are arranged one-dimensionally. As shown, the left end side is the upstream direction and the right end side is the downstream direction. The device on the left is
The parent device for collecting sensor information and monitoring control information from other wireless devices is indicated by M1, and all other wireless devices are child devices for sending information to the parent device, and Sn (n = 2 to N). ) N-
It is assumed that there is one. All wireless devices have a series of IDs (identifiers) as address numbers associated with their installation positions, and the master device at the left end of FIG. Similarly, the rightmost end is set to ID = N. It is assumed that each radio has an input / output function terminal Tk for exchanging external information, for example, measurement data such as a sensor. (Here, k = 1 to N) It should be noted that there is no essential difference between the master unit and the slave unit as a wireless function, and the master unit manages and controls the entire wireless communication system and has a function of processing collected information. It only has application functions such as.
Further, the initial installation interval L of each wireless device is set to be equal to or less than half of the reaching limit of one transmission of this wireless signal.

(A) It is assumed that each radio has at least a half-duplex communication function. The wireless medium may be a radio signal or an optical signal such as infrared communication. Also,
In the case of radio waves, the radio wave format may be a narrow band method or a wide band method such as a spread spectrum method.

(C) Each wireless device digitizes the information taken in from its own input / output terminal at a pre-assigned timing, packetizes it as a block of a certain fixed length, and further wirelessly transmits it. The signal is modulated according to the characteristics of and is sent on the radio signal.

(D) The format of the packet is

As shown in FIG. 2, a preamble of an appropriate length (abbreviated as PA) for ensuring a reception operation of a wireless packet, a synchronization code indicating a boundary between PA and a packet body (a pattern by a specific code string) (Hereinafter also referred to as a unique word abbreviated as SYN), a radio ID (Destination Addr) indicating the final destination of this packet.
ess, DA field), and the radio ID (Source Address) of the first generation source of this packet.
abbreviated as ss and SA field), a control field (C field) for instructing how the wireless device receiving this packet should handle, and a user information I
Field, a check code for checking the presence or absence of a bit error in the bit string after the DA field (hereinafter referred to as “Cyclic Redundancy Che”).
Abbreviated as ck-code and CRC. FCS frame check sequence). Further, a gap (GAP) is added in advance of the PA so that meaningful field portions of adjacent time slots do not overlap each other on the time axis even if there is a slight error in the clock function incorporated in each radio. It In addition to the fixed packet length method, the variable packet length method is essentially applicable. In this case, the data from DA to CRC is HD.
It is surrounded by the FLAG pattern in LC.

The C field is further provided with an "upstream / downstream" indicator bit, I, which indicates the direction of transmission of this packet.
"Empty / indicates whether the field is already in use
"Clog" indicator bit, "Packet type" bit indicating the meaning and attribute of the I field, "Time stamp" indicating the time when this packet occurred, "Sequence number" for detecting duplication or omission when receiving a packet, "Relay number" where the ID of the wireless device that replayed and relayed the packet is written
Etc. are composed of bit strings. In the C field,
The "relay number" field is rewritten every time a packet is relayed, but the other fields remain unchanged until this packet is taken into the radio indicated by DA and disappears. The time stamp and the sequence number are not functions related to the essence of the operation of the present invention, but they are for ensuring the wireless packet relay operation.

(E) The length of a radio signal transmitted by one radio at a certain time is called a time slot (denoted by TS). This TS is common to all radios and is constant,
Let its length be Tp.

Assignment of packet transmission right and direction of shift of transmission right between radios Assignment of packet transmission right is time-divisional. That is, each radio has a built-in clock function, and when the transmission allocation time of its own is reached, transmission is permitted for the time Tp of one time slot length. At this time, the information to be carried in the transmission packet may be relayed by the information of the adjacent wireless device which has already been received and temporarily stored, or may be transmitted by carrying the information held by itself. The transmission right that can be transmitted by the time width of this time slot is shifted between adjacent radios at Tp time intervals. This situation is

FIG. 4 shows an example in which the number of wireless devices is five. The direction in which the time shifts is "downward mode" in which the master unit shifts toward the slave unit, and "upward mode" in which the slave unit farthest from the master unit sequentially goes toward the master unit. Of 2
There is a street. In this figure, it is an example of the “upstream mode”. Which mode is used depends on which direction the information transmission delay is emphasized, and the mode switching can be fixed, semi-fixed, or automatic. Which method is adopted may be arbitrarily determined depending on the application purpose of this system.

(F) Time slot allocation method There are two ways of establishing the relationship between the number M of time slots and the number N of radio devices. (A) Method of setting M ≧ N (b) Method of setting M <N

First, the case (a) will be described. The time slot numbers of N units, which are set so as not to overlap on the time axis, are TS-1, TS-2, ... TS-N.
If this is specified, this number can be assigned without duplication with the ID of the wireless device, so there is a one-to-one correspondence with the installation position of the wireless device.
Means to be associated with.

FIG. 5 shows a state in which the transmission right shifts between radios with time in units of TS in such a case. The feature of this method is that since there is always one radio device transmitting a radio signal at the same time, collision of radio signals cannot occur in any case. This is suitable for small systems.

Next, the case (b) will be described. In this method, the number of TSs is smaller than the number of radios, and the same TS
The number is repeatedly assigned to a plurality of wireless devices. In this case, if the same TS is assigned to adjacent radios, the radio signals interfere with each other, and therefore the radios are assigned to radios separated by a certain distance or more. How many intervals the overlapping TSs are allocated to prevent mutual interference depends on the characteristics of reception / reproduction of the radio signal in addition to the attenuation characteristics with respect to the distance of the radio signal. The advantage of this method is that even if the number of wireless devices increases, the time required for the transmission right to complete a cycle does not become longer than a certain amount, and is suitable for a large-scale system. The above relationship

FIG. 5 shows.

(G) In connection with the above description, various methods can be considered as means for establishing "phase synchronization of time slots". One method is a subordinate synchronization method, and the operation is generally as follows. The most upstream or most downstream radio first sends a packet. The wireless device in the vicinity receiving this can easily calculate the time slot number to be assigned to itself from the SA of the received packet and the value of its own ID. If there is a bit error in the received packet, it may be discarded, and then the packet transmitted by another nearby radio device may be monitored to wait until the correct packet is received. Further, the exact time when the packet is received is based on the time point when the SYN pattern is detected, so that the TS phase can be adjusted with an error of the propagation time of the radio signal.

(H) The initial packet transmission operation is as follows. When the system starts up, the first packet that can be sent is

1 is a wireless device as a left end (master device) or a right end slave device in FIG. 1, and continues to transmit packets at a constant cycle until the system changes its operation mode. Therefore, the radio set at the left end or the right end has a time slot generator function.

Which side of the time slot generator starts transmitting a packet at the time of initial startup depends on whether the operation of this system is in the "upstream mode" or the "downstream mode", and is generally In addition, when the master unit collects information from the slave unit group, the information transmission time is shorter in the “upstream mode”, that is, when the rightmost slave unit is the “time slot generator”.

Considering a case where the number M of time slots is equal to the number N of radio devices, the cycle Tc of packet transmission is Tc = N × Tp. In the direction in which the packet transmission right is shifted, the IDs of the radio devices are N, N-1, ... 2, 1 in the "upstream mode", and 1, 2, ... in the "downstream mode". The order is N-1, N. In the "uplink mode", the radio that serves as the packet generator is
In the “downstream mode”, the child device with D = N has ID = 1 (that is, the parent device).

The radio which firstly transmits the packet can put its own information on this packet, and at this time, the "empty / blocked" indicator bit in the C field of the packet header is set to "blocked". set. In the other cycles, the packet indicating "empty" is Tc
Is sent every cycle. When sending a "vacant" packet, an integer "J" that is incremented or decremented by 1 each time it is sent is written in the I field. This J indicates a wireless device ID that can carry its own information when this empty packet is received.

(X) The operation of the slave unit when receiving a packet is as follows. All radios are always ready to receive packets. A child machine, here
Description will be made assuming that a packet with a certain ID = kth (k is 1, other than N) wireless device is received. When viewed from a wireless device (slave device) having an ID k, ID = k + 1 is a downstream adjacent slave device, and ID = k−1 is an upstream adjacent wireless device (slave device or master device). If the CRC of the packet received by the wireless device with ID = k is a normal packet with no error, it is temporarily stored in the buffer memory. If an error is detected, discard it. The subsequent operation is either "uplink mode" / "downlink mode" or S of the received packet.
4 depending on whether A is greater than or less than k
Break up on the street. Here, the case of the "upstream mode" will be described.

When the SA of the received packet is larger than k. Compare with the time stamp and sequence number of the header of the packet that has already been received and temporarily stored, and if the same,
It can be judged that the packet received earlier is a packet transmitted by a downstream radio set which is two or more away from the other, and the packet received this time is overwritten in the buffer memory to update the contents of the buffer.

When the SA of the received packet is smaller than k. This received packet is a packet transmitted by the adjacent radio located upstream to the upstream (it can be easily judged by the destination DA of the packet), and normally this packet is discarded in the radio with ID = k. You may However, it can be used as statistical information for monitoring the operating state of the adjacent wireless device. Although the case of the “upstream mode” has been described above, the operation is the same for the “downstream mode”.

(C) The operation of the slave unit during packet transmission is as follows. Each radio can send a radio signal only when the timing of a pre-assigned time slot is reached. The information to be put on this radio signal is the same as the case of simply relaying the packet from the adjacent radio that has already been received and temporarily stored / stored in the explanation in the above (v), and the data owned by itself to the parent device. There are two ways to make a call.

(A) When the previously received packet is not displayed as "vacant". This kth child device relays this packet. that time,
The ID of the "relay node number" field in the header
Replace with (= k). Naturally, the CRC is recalculated.

(B) When the previously received packet is displayed as "vacant". In this case, the information held by itself can be put in the I field of the packet. At this time, the DA of the packet header (in the "upstream" mode, usually the ID of the base unit
= 1), SA (k in this example), "Free / closed display"
Is rewritten as "closed". At the same time, a packet is transmitted by adding a preamble to the head of the frame of the packet body.

(S) Thus, the packet data of the wireless packet data is successively relayed between adjacent wireless devices as if it were a "bucket relay", and the wireless device of the final destination (the master device in the above description of the operation example). ), Where the packet is absorbed and disappears.

(V) Although the above description of the operation is based on the case of the "upstream mode", the basic operation principle is the same in the case of the "downstream mode".

(S) Handling of Packet Error In packet communication via a wireless line, it is of course necessary to consider that bit errors occur stochastically. A method applicable in the wireless packet communication system according to the present invention is

(A) Instead of CRC, an error correction coding method (Fourard Error Correction, F) is used.
EC) is abbreviated). (B) A method of performing error detection by CRC and performing retransmission correction as necessary (contents of information, etc.). (C) A method in which an error is detected by CRC but not corrected. There is. Which method is better depends on the actual transmission quality (bit error rate) of the wireless line, the content and nature of the information transmitted in packets, the allowable value of delay time associated with packet transmission, etc.
The options change depending on the application. As in the present invention, for example, when a packet error occurs in the “upstream mode”, in the retransmission correction method of (b), the timing at which the packet to be retransmitted can be sent is delayed until the cycle of the next time slot. , It is difficult to make a quick corrective action. When it is necessary to deal with such a problem, the method (a) or (c) is used. In the case of an application that periodically collects sensor information and measurement data to perform monitoring control, and the transmission quality is a relatively good condition with a bit error rate of about 1 × 10 EXP (−5), the method (c) above is used. Can also be applied.

(E) As can be seen from the above description, according to the present invention, all the wireless slave units can switch between the packet relay operation and the packet transmission operation by simply checking the packet header. It has the feature of not requiring a repeater.

(S) As is clear from the above description, in the present invention, the radio signals transmitted by a radio device are arranged at intervals of the radio devices so as to over-reach at least one adjacent radio device. Therefore, even if the wireless device on the way fails and the relay operation cannot be performed, an algorithm can be realized in which the wireless device skipped by one can perform the packet relay, and the packet relay operation is not interrupted. This is another feature of the wireless packet relay system according to the present invention.

(A) In the above description of the outline of the operation, the case where the wireless device transmits one packet in one time slot has been described. Further, by expanding the time slot so that two or more packets can be concatenated and transmitted in one time slot, different packets can be sent to both the upstream and downstream radios at one transmission opportunity. Can be delivered. By doing so, the preamble portion can be shared, and the feature that the wireless line can be effectively used can be obtained. The packet configuration at this time

FIG. 3 illustrates. In the figure, the concatenated packets −
1, the structure of the contents of packet-2 is basically

2 is similar to FIG.

[0039]

[Supplementary explanation related to the present invention] As the wireless medium in the above description, not only radio waves but also light (application of infrared rays)
Etc. are also possible and are not particularly limited. The digital data modulation method suitable for the wireless medium may also be suitable for the characteristics of the wireless medium.

Further, as the embodiment of the present invention, the wireless packet relay system in the case where the wireless device group is installed one-dimensionally has been described so far, but the wireless device group is installed two-dimensionally. The present invention can be applied by expanding even in the case where it is present, and a plurality of linear radio packet relay paths can be configured.

FIG. 6 shows the configuration of a wireless packet relay system conceptually depicting this embodiment. As is clear from the figure,
It can be realized by radially connecting a plurality of relay paths for wireless packets. In this case, even if the radio carriers (f1 to f4) are not changed for each relay path, the phase of each time slot may be adjusted to avoid mutual interference between radio signals on each relay path.

[0041]

According to the present invention, all radios have the function of transmitting and receiving packetized data by using only one radio carrier, and also have the function of relaying, so they are specialized as repeaters. It is possible to configure long-distance wireless packet communication without using a device. This can improve the economical efficiency of the wireless packet system. Further, according to the present invention, even if the reliability of the wireless packet relay according to the conventional method is deteriorated due to the failure of the wireless device or the relay device on the way, the interval between the wireless devices is set so that the wireless signals are overreached. By arranging it, the interlaced relay is automatically performed. As a result, a local failure does not affect the packet relay function of the entire system, and the reliability of the operation of the entire system can be improved.

[Brief description of drawings]

FIG. 1 is a typical example of a system configuration according to the present invention, showing a case where the number of radio devices is five.

FIG. 2 is an example of a frame format of a wireless packet used when the present invention is applied.

FIG. 3 is another example of the frame format of another packet when the present invention is applied, and is a frame format showing a packet configuration example when two packets are concatenated and transmitted in one time slot. Illustration.

FIG. 4 is a matrix diagram for explaining the relationship between a time slot and a radio group for explaining the operation concept of the present invention. In the case of the "upstream mode", the transmission right is depicted as being shifted in the upstream direction. Also, in this example, the ID
= 5 shows the case where the radio device has the function of the time slot generator.

FIG. 5 is another matrix diagram for explaining the relationship between the time slot and the radio set for explaining the operation concept of the present invention. In this figure, the number of time slots is set to 5 with respect to the number of radio apparatus 10, and 10 sets of radio apparatuses use the time slots of the same phase in an overlapping manner.

FIG. 6 is another configuration example of the wireless packet relay system to which the present invention is applied.

FIG. 7 is a diagram showing an example of a configuration of a collection system of measurement / control information and the like according to the conventional method, in a case where the terminals connected in a distributed manner are star-shaped wiring by wire.

FIG. 8 is a diagram showing another example of the configuration of the conventional system for collecting measurement / control information and the like, in the case where the distributed terminals are connected to each other by a wired bus type.

FIG. 9 is a diagram showing a configuration of a collection system of measurement / control information and the like according to the conventional method, but in a case where the connection between the distributed terminals is wireless. An example of combining with some star type wiring is shown.

FIG. 10 is a diagram of a configuration of a collection system of measurement / control information and the like according to a conventional method, in a case where connections between terminals that are distributed and installed are wireless only.

FIG. 5 is another matrix diagram for explaining the relationship between the time slot and the radio set for explaining the operation concept of the present invention. In this figure, the number of time slots is set to 5 with respect to the number of radio apparatuses 10, and 10 radio apparatuses are shown to use time slots of the same phase in an overlapping manner.

FIG. 6 is another configuration example of the wireless packet relay system to which the present invention is applied.

[Explanation of symbols]

 11 Master device having wireless function according to the present invention 12 Handset device having wireless function according to the present invention 13 Input / output terminal device 14 Packet frame format 15 Extended packet frame format 21 Master device having conventional wired communication function 22 Conventional device A cordless handset 31 A base unit having a conventional wireless communication function 32 A handset having a conventional wireless communication function 40 A conventional wireless repeater The abbreviations used in the figures have the following meanings. On the street.

FIG.

[Fig. 4]

[Fig. 5]

[FIG. 6]

[FIG. 7]

FIG. 8

FIG. 9 and

In FIG. 10, f1, f2, f3, f4 radio carriers L1 −−− L4 radio equipment intervals when the present invention is implemented ID serial number for radio equipment identification L1, L2, L3 conventional radio installation Interval TS time slot

FIG.

In FIG. 3, B / R is a block / empty indication bit C is a control information field CRC, CRC1, CRC2 is a cyclic redundancy check code DA is the final destination address (radio unit ID number) I, I1, I2 is a user information field GAP packet transmission Gap PA Preamble PAT Packet attribute display PH1, PH2 Two different packet headers RNI Packet I
D SA Source address (radio device ID number) SN Sequence number when packet is generated SYN Sync code TB Training bit string TSP Time stamp when packet is generated TS Time slot TS-E Extended time slot U / D Up direction / Downward direction display bit Even if the drawing numbers are different, the same symbols represent the same meaning.

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[Procedure amendment]

[Submission date] December 8, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of drawings]

FIG. 1 is a typical example of a system configuration according to the present invention, showing a case where the number of radio devices is five.

FIG. 2 is an example of a frame format of a wireless packet used when the present invention is applied.

FIG. 3 is an example of a frame format of another packet when the present invention is applied, and is a diagram of a frame format used when two packets are concatenated and transmitted in one time slot.

FIG. 4 is a diagram for explaining the operation concept of the present invention, and is a matrix diagram of radio device IDs and time slots showing a situation in which transmission rights are moved among a plurality of radio devices. This is a case where five wireless devices and five time slots are used.

FIG. 5 is another matrix diagram of radio device IDs and time slots when the number of radio devices is 10 and the number of time slots used is 5, and the same time slot is shared by two sets of radio devices. Is shown.

FIG. 6 shows another configuration example of the wireless packet relay system to which the present invention is applied, in which a plurality of wireless packet communication paths (4 in this figure) are present in one system.

FIG. 7 is a diagram illustrating a configuration example of a collection system of measurement / control information and the like according to a conventional method, in a case where wired star-type wiring is used for connection between terminal devices that are distributed and installed.

FIG. 8 is a diagram illustrating another example of the configuration of the conventional system for collecting measurement / control information and the like, in which wired bus type wiring is used for connection between terminal devices that are distributed and installed.

FIG. 9 is a diagram showing a configuration example of a collection system of measurement / control information and the like according to the conventional method, in a case where wireless is partially used for connection between terminal devices distributed and installed.

FIG. 10 is a diagram showing an example of the configuration of a collection system of measurement / control information and the like according to the conventional method, in a case where wireless is all used for connection between terminal devices that are distributed and installed.

[Description of Reference Signs] 11 Parent device having wireless function according to the present invention 12 Handset device having wireless function according to the present invention 13 Input / output terminal device 14 Packet frame 15 Expanded packet frame 21 Parent having conventional wired communication function Device 22 Slave device having conventional wired communication function 31 Master device having conventional wireless communication function 32 Slave device having conventional wireless communication function 40 Conventional wireless relay B / R Blocked / empty indication bit C Control information field CRC, CRC1, CRC2 Cyclic redundancy check bit DA Destination address (radio device ID number) field f1, f2, f3, f4 Radio carrier GAP packet transmission time gap I, I1, I2 User information field ID Serial number for radio identification L1, L2, L3, L4 Radio installation Interval PA Preamble PAT Packet attribute display PH1, PH2 Packet header RNI ID of the radio that relayed the packet Source address (radio ID) field SN Sequence number at the time of packet generation SYN sync code field T1, T2, T3, T4 Input / output terminal equipment (reference numeral 1)
The same meaning as 3) TB training bit string TS time slot TS-E extended time slot TSP packet time stamp U / D upstream / downstream indication bit The same symbol has the same meaning even if the drawing number is different. Represent

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tagaichi Yamazaki 9-1 Niizumi, Narita, Chiba Tekken Construction Co., Ltd. Technical Research Institute

Claims (3)

[Claims] 1. A plurality of radio groups having a half-duplex radio transmission function are geographically arranged in a straight line, and signals are not attenuated and reach all radios in one transmission. In the case where there is a total length of the straight line distance, the information acquired by the input / output function of each radio device is used to specify one radio device specified from among the plurality of radio devices (hereinafter, the specified radio device In a wireless packet communication system that periodically collects data by a packet communication method (referred to as a master device), the direction in which the master device is located is the upstream direction, and the direction away from the master device is the downstream direction, as illustrated in FIG. 2 is a packet relay system by wireless transmission characterized by having the following functional conditions, and the installation interval of each wireless device is 1/2 or less of a distance L at which a wireless signal normally reaches. By doing Arranged so as to overreach to radios other than adjacent radios, a series of unique identifiers (hereinafter abbreviated as IDs) associated with installation positions are given to all the radios. After each radio has applied appropriate modulation to packetized data (hereinafter referred to as a time slot) in a fixed length in the order of timing associated with its linearly distributed positions, It has the function of transmitting as a radio signal, while all other radios constantly listen to this transmitted radio packet for normal (error-free)
In the case of packets, it has a function of temporarily storing, and either one of the above-mentioned linearly installed radios located at the most upstream end or the most downstream end stores the fixed-length packet data in a certain fixed period. It is sent repeatedly and the packet contains
A header indicating whether the packet should be relayed upstream or downstream and whether the packet is "vacant" is added. When it comes to the timing pre-allocated to your wireless device, check the "empty / blocked" display in the header of the latest packet that has already been received and is temporarily stored. For example, if the information held by the user is packetized, and if the above-mentioned display is "blocked", the received and temporarily stored packet is retransmitted as it is in the time slot, as if it were a bucket relay. A wireless packet relay method characterized in that information is delivered to a far-end parent wireless device that cannot be reached by a single wireless signal transmission by repeating forward relay. In the bucket brigade relay operation, wireless packets received from radios far from and adjacent to each other are also temporarily stored, and when normal packets cannot be received from the radios adjacent to each other, the radios from two or more radios beyond the adjacent radios are skipped. A packet relay method by wireless transmission, in which the relay function is maintained and continued even if you skip over adjacent wireless devices by relaying packets. 2. When the number N of wireless devices installed in the wireless system as a whole and the number M of time slots are set in the above-mentioned claim 1, N> M is set so that there is an interval between the wireless devices. A packet relay method by wireless transmission that is characterized by shortening the delay time in packet relay operation by repeatedly using time slots of the same phase in sections separated by a certain amount or more. 3. In the above claim 1, as shown in [FIG. 3], two packets having different destinations in the upstream direction and the downstream direction are concatenated in the time slot and are transmitted at one transmission timing. As a result, the packet relay method by wireless transmission is characterized in that the preamble portion added to the head of the packet is shared to improve the use efficiency of the wireless line.