JP2004007491A - Data distributing system in data communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To distribute information transmitted from one node to all nodes in a data communication network using indoor power lines or radio means, etc. <P>SOLUTION: In broadcasting data to distribute information widely to individual nodes, a system requests to further broadcast the same data, so far as the node having received the data does not meet stop conditions. In the request to broadcast the data, it indicates the timing of a broadcasting operation with shifted timing between the nodes. On the basis of a received broadcast transmission address, it gives a sequence (m) to all the nodes in a specified order from its transmission address and transmits a broadcast to the nodes in the sequence (m) with a (m+3)-th slot set at the head where the next slot at the tail end of a previous broadcast is a first one. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a data distribution method for distributing information to all nodes in data communication of a small-scale network in which connection between links remains unstable, such as an indoor power line or a home network using wireless communication.
[0002]
[Prior art]
In a LAN represented by Ethernet, there is a method called “broadcast” in which a destination (destination) address is all “1” (for example, see Patent Document 1).
[0003]
In such a broadcast method, a node that has received a packet (or a frame) having an all-one address as a destination interprets the frame as addressed to itself and takes in data. In order to do this, it is premised that a frame output from one node reaches all nodes even if there is a slight transmission error. The receiving side knows that a slight transmission error has occurred due to an error detection redundant bit attached to the frame or the like, so that error-free information can be received, for example, by requesting retransmission. Conventional data communication has been configured based on such a stable network.
[0004]
[Patent Document 1]
JP-A-11-317755
[0005]
[Problems to be solved by the invention]
However, in a network using an indoor power line or wireless communication, some instability is inevitable. It is known that, for example, when a microwave oven starts operating in an indoor power line or wireless communication, noise increases and a link passing near the microwave oven temporarily becomes unstable. Such a phenomenon is referred to as "inaudible". When a terminal constituting a nearby node becomes inaudible, it is called a “hidden terminal”. In a network where there are nodes that cannot be heard in this way, information does not always reach all nodes by conventional broadcast alone.
[0006]
To overcome such a situation, a technique called “broadcast relay” is used, in which all nodes that receive a broadcast issued by one node broadcast the same information. The condition for using this is that when the information arriving by this broadcast relay has already arrived, no further broadcast is performed.
[0007]
In this case, the broadcast relay stops when the information is distributed to all nodes. This condition is called a “stop condition”. A disadvantage of conventional broadcast relay is that the next traffic occurs at many nodes in synchronization with one broadcast causing the next broadcast.
[0008]
When many collisions occur in a shared media type network such as an Ethernet, an indoor power line, or a wireless network, the network may be radiated. Once a collision occurs in any network, the same information is then retransmitted again, but this retransmission may collide. Therefore, in order to avoid collisions at the time of retransmission as much as possible, a delay is inevitable because retransmission is strictly controlled, such as providing a certain period of silence after a collision occurs. Therefore, there is a need for a method for preventing collision.
[0009]
The present invention has been made in view of such circumstances, and in the data communication of a relatively small network such as a home network using an indoor power line or wireless communication, information transmitted by one node is transmitted within the network. The purpose of the present invention is to provide a data distribution method capable of reaching all the nodes of the data distribution system.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a method for dividing a transmission time of a basic packet, which is a basic unit of data communication, into n divisions (n = 1, 2, 2, 3) at the timing of each node in a data communication network using an indoor power line or wireless communication. ...) and a slot clock generating means for generating a slot clock for making the division unit a slot and a transmission time unit, and broadcasting data for disseminating information to each node, Unless the node receiving the data satisfies the stop condition, request means for requesting further broadcast of the same data, and when requesting a broadcast in this request means, the broadcast is shifted in timing between the nodes. Timing instruction means for instructing the When there is an instruction to cause the broadcast, the order m is given to all the nodes in a fixed order from the transmission address based on the transmission address of the received broadcast, and the next slot at the end of the previous broadcast is made the first. With the (m + 3) th slot at the head, if a broadcast is transmitted to the node in order m and there is no instruction to shift the timing between the nodes, the broadcast is separated from the end of the previous broadcast by at least three slots. Transmission means for transmitting.
[0011]
In the present invention, since a data communication network using an indoor power line or wireless which remains unstable is premised, a basic packet is introduced as a unit of data communication. Moreover, in order to measure the length of the basic packet and control the start of transmission of the next basic packet after the end of the packet, a slot in which the basic packet is divided into n (n = 1, 2,...) Is basically used. Introduced as a simple time unit.
[0012]
In the present invention, a broadcast relay method is adopted, and when a node receiving a broadcast satisfies a stop condition, broadcast relay is not continued any more.
[0013]
On the other hand, a node that does not satisfy the stop condition performs broadcast transmission, but at the time of the broadcast transmission, issues an instruction to shift the timing between the nodes, and adjusts the timing of the broadcast transmission based on the transmission address of the received broadcast. Given the order m to all the nodes in a fixed order from the transmission address, and when the next slot at the end of the previous broadcast is the first slot, the (m + 3) th slot is first and broadcast to the node in the order m. Send In this way, information transmitted by one node can be delivered to all nodes in the network.
[0014]
If the instruction to shift the timing between the nodes is not issued, the broadcast is transmitted at least five slots away from the end of the previous broadcast. By doing so, the number of nodes satisfying the stop condition in the network increases, and the congestion does not occur in the network because the flowcast relay is rapidly collected.
[0015]
In the present invention, in order to shift the timing between nodes, while counting the leading slot for each node, a basic packet having a t slot length (t = 2, 3, 4,...) Means may be provided to increase the count value of the first slot by (t + 2) every time is transmitted. Furthermore, if the node in order m from the beginning decides to send out a packet of length t starting from the {3m + 1 + t (m-1)} th slot, it is possible to determine whether another packet is inserted before packet transmission. No need to monitor. This is also included in the present invention.
[0016]
The present invention divides the transmission time of a basic packet, which is a basic unit of data communication, into n (n = 1, 2,...) At the timing of each node in a data communication network using an indoor power line or wireless communication. A slot clock generating means for generating a slot clock for making a unit of a transmission time with a unit as a slot, and when broadcasting data for disseminating information to each node, a specific node is designated, The requesting means for requesting to repeat the broadcast transmission, and the node requested to repeat the broadcast transmission by the requesting means starts the broadcast transmission to be repeated from the end of the broadcast packet with a smaller slot gap than the normal packet. Characterized by the provision of It is.
[0017]
According to the present invention, information can be delivered to all nodes that can directly communicate with two nodes that are parties to data communication.
[0018]
Each functional unit (means) constituting the data distribution system of the present invention is provided, for example, at each node connected to the data communication network.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
First, an outline of an embodiment of the present invention will be described for each item.
[0020]
[Basic packet transmission method]
In the present invention, in order to minimize collisions in broadcast relay, collisions are prevented by shifting the start point of the second broadcast caused by the first broadcast for each node.
[0021]
In the present embodiment, the basic data transmission unit of the data communication system is an 8-byte (64-bit) packet, which is referred to as a basic packet. Since the data transmission speed is 2 Mbps, the basic packet is 32 μsec long.
[0022]
In each node, the time corresponding to half the length of the basic packet, that is, the time corresponding to the transmission of 4 bytes is called a slot, and this is used as the basic time unit of data transmission. Therefore, the basic packet is transmitted using two slots. This division into slots is performed independently by each node, and phase adjustment between nodes is not performed.
[0023]
The transmission of the basic packet is performed without taking measures for avoiding collision. First, it is confirmed that no other signal exists in the shared medium, and transmission is started from the head of its own slot. This helps to prevent collisions since the beginning of this slot is slightly offset between nodes. The reason will be described with reference to FIG.
[0024]
In FIG. 1, when the node A sends out the basic packet 11, a signal is transmitted with a propagation delay indicated by 12, and the signal transmitted by the node A reaches the node B slightly before the time of the head 13 of the slot. Node B does not send out data in slots starting at 13. That is, it is useful for collision avoidance.
[0025]
However, the signal from the node A reaches the node C with the propagation delay indicated by 12 slightly later than the head 14 of the slot of the node C, so that the node C sends out the basic packet 15. Therefore, the packet of the node A and the packet of the node C collide. However, the end of the packet of the node A arrives at a point 17 slightly later than the end 16 of the packet of the node C. The node transmitting the packet monitors the signal on the slot, and the node C terminates the packet transmitted by itself. Even notice that there is a signal in the next slot. This indicates that a collision has occurred.
[0026]
In the present embodiment, as shown in FIG. 2, if a basic packet is sent out or detected, the rule is that five slots after the end of the basic packet have a silence period during which no data is transmitted. Furthermore, when the end of the basic packet is at a time other than the slot break itself, five slots following that slot are set to the silence time. This makes it possible to determine whether or not the basic packet transmitted by itself has collided.
[0027]
Upon detecting this collision, the node C issues a NAK (unreceivable) command in the gap of one slot shown in FIG. Although small in probability, the basic packet from node A and the basic packet from node C may completely overlap in node C in two slots. In that case, node C cannot detect collision.
[0028]
However, the phase of the basic packet from the node A and the phase of the basic packet from the node C are shifted from one another in any of the nodes in the network, and the basic packet is received out of two slots, so that a collision can be detected. At that time, the node that has detected the collision broadcasts a NAK command in one slot gap. Nodes A and C that hear this retransmit the basic packet.
[0029]
[Gap after receiving basic packet]
Next, the gap after receiving one ordinary basic packet will be described with reference to FIG.
[0030]
First, since the slot does not adjust the phase between nodes, the received basic packet 21 does not coincide with the end and end of its own slot. Therefore, the slot in which the end of the received basic packet 21 is located is ignored, and a gap is made from the next slot. That is, a case where only the slot of reference numeral 22 is a gap is referred to as a one-slot gap, a case where two slots of reference numeral 23 is a gap, and a case where three slots of reference numeral 24 are a gap. I do. Normal packets have at least a 5-slot gap and transmit in the next slot.
[0031]
By doing so, a node that detects a collision with respect to basic command transmission broadcasts a NAK command in a one-slot gap.
[0032]
[Data distribution method]
First, since a collision is likely to be detected at many nodes, a NAK command is also likely to collide. However, since only a NAK command can be transmitted in one slot gap, the presence of the command here itself means that a collision has occurred.
FIG. 3 shows a configuration of a basic packet used for data communication. The basic packet shown in FIG. 3 is composed of two slots, and is composed of an 8-bit destination address, an 8-bit source address, an 8-bit command, a 16-bit data portion, and 8-bit error correction redundant bits. I have. Among them, the one whose destination address is all 1 is broadcast, and all nodes connected to the network are to be received. However, as described above, even in a network where instability remains, even if the broadcast is sent, it does not necessarily reach all nodes.
[0033]
FIG. 4 shows the configuration of the control unit shown in FIG. In FIG. 4, each delimiter represents a bit, and if there is 1 in the first bit, it indicates retransmission. If the second bit is 1, it means requesting to relay the information to be transmitted by broadcast of the basic packet by broadcast.
[0034]
The node requesting the broadcast relay is indicated by the auxiliary address section in FIG. When the auxiliary address portion is all 1, a request is made to all nodes that have received the broadcast to perform broadcast relay.
[0035]
The third bit in FIG. 4 requests timing control. When 1 is set in the second bit and the third bit, all nodes are set in a predetermined order based on the transmission node address of the received broadcast. Make an order.
[0036]
Assuming that the order is m (m = 1, 2,... 254), the next slot at the end of the broadcasted basic packet is counted as 1, and the (m + 3) th slot is the next node in the order m. Is a slot where broadcast transmission may be performed. Moreover, if another node broadcasts the basic packet before the turn comes, the (m + 3) -th is counted instead of counting the number of slots of the basic packet + 2 slots.
[0037]
FIG. 5 shows an example of the order in which this order is counted.
[0038]
In FIG. 5, counting is started from the address one address lower than the transmission address, and the addresses are assigned in the direction of smaller address. Unused addresses are not ordered. When the address reaches the minimum address of 1, the circuit circulates to the maximum address and assigns an order in the direction in which the address becomes smaller again.
[0039]
In this case, the address 6 is broadcast-transmitted with the next slot, that is, the fourth slot from the end at the head, with a gap of three slots from the end of the previous packet. The address 5 is broadcast-transmitted to the ninth slot at an interval of eight slots including two slots of the basic packet of the address 6.
[0040]
At address 4, no broadcast is heard from address 7, so nothing is transmitted. Since the address 3 is not used, the address 2 is transmitted at the 14th slot with a gap of 13 slots. However, if a broadcast basic packet comes out from address 5, this will be the 19th slot. Since these broadcast transmissions are timing-controlled, 1 is set in the “timed control” of the fourth bit in FIG. In addition, the slot gap is set to 5.
[0041]
When BDR (broadcast relay request) = 1, TCR (timing control request) = 1 and the broadcast of all auxiliary addresses 1 are received, the timing control as shown in FIG. 5 is performed, so that BDR = 1 and TMC (timing control ) = 1, broadcast relay with all auxiliary addresses 1 The node receiving this broadcast is likely to satisfy the stop condition. In that case, the broadcast relay is not continued any more.
[0042]
A node that does not satisfy the stop condition broadcasts BDR = 1 and the auxiliary address all 1, but in this case, the transmission is performed with a gap of 5 slots in FIG. By doing so, the slot gap is increased by two slots as compared with the broadcast relay in the case of the broadcast reception with TCR = 1, so that the priority is lowered. The first round of broadcast-controlled broadcast relay takes precedence, and after the second round, the number of nodes satisfying the stop condition increases, and the flowcast relay rapidly converges, so that no congestion occurs in the network.
[0043]
Further, in the case of information that needs to be thoroughly known to all nodes that can directly communicate with the two nodes that are parties to data communication, one of the two sets the information to BDR = 1 and the auxiliary address sets the other to the other. Broadcast transmission of one node address may be performed. Then, only the node specified by the auxiliary address broadcasts the information with BDR = 0. As a result, any broadcast transmission reaches a node that can be directly heard from the two nodes.
[0044]
Next, more specific embodiments of the present invention will be described.
[0045]
6 and 7 are block diagrams showing the configuration of the embodiment of the present invention. Each configuration (functional unit) shown in FIGS. 6 and 7 is provided in each node connected to the network.
[0046]
In this embodiment, first, the clock generated by the basic clock generator 101 is sent to the 1 / 256-slot clock generator 102 to create a slot length 1 / 256-slot clock. To generate a slot timing clock. This slot clock is supplied for counting the slot gap described in FIG.
[0047]
A signal from the network is received by the receiving circuit 104, and separated by the basic packet receiving unit 105 and other receiving units 106 into the basic packet and the rest. After the presence of the signal is extracted from the received signal level in the received signal detection unit 107, the AND packet (logical product) of the basic packet is compared with the logic of the 1/256 slot clock from the 1/256 slot clock generation unit 102 in the AND circuit 108. The product is taken. The result of the logical product (the number of pulses) is counted by the basic packet length counting unit 109, and when approximately 512 pulses are counted, it becomes the length of the basic packet in consideration of the tolerance.
[0048]
If the count in the basic packet length count unit 109 is approximately 512 pulses or more, it is determined that a collision has been detected, a "count over" signal is output, the collision detection unit 110 is activated, and the collision command creation unit 111 detects a collision. A command is generated, and the one-slot interval described in FIG. 2 is counted by the one-slot gap counting unit 112 and transmitted from the transmission circuit 113 to the network.
[0049]
The one-slot gap counting unit 112 receives the slot clock from the slot clock generation unit 103 and the information on the end of the basic packet detected by the basic packet length counting unit 109 in order to count the one-slot gap.
[0050]
On the other hand, the received command interpreting unit 114 receives the basic packet signal from the basic packet receiving unit 105, confirms that the basic packet length matches the basic packet length in the basic packet length counting unit 109, and interprets the received command. The determination unit 115 determines whether or not is a broadcast. If the result of the determination is NO, it does not directly relate to the present invention, and a detailed description thereof will be omitted here.
[0051]
If the result of the determination by the determination section 115 is YES, the processing distribution section 116 divides the processing into three types according to the contents of the control section shown in FIG.
[0052]
Specifically, when the BDR of the control unit is 0, the broadcast is an ordinary broadcast, and the process is left to the related processing. When BDR = 1 and TCR = 1, it corresponds to the first-order broadcast relay, so that the timing control process is started, and the own address is assigned an order m in the own address ordering unit 117. The order is predetermined. In the order given. As an example, as shown in FIG. 5, a method is adopted in which, based on a transmission address, an order starting from 1 is assigned in a direction in which the address becomes smaller.
[0053]
Assuming that the order given by the own address ordering unit 117 is m, the count setting unit 118 sets the value of the count M of the slot gap to m + 3. For this counting, the slot clock from the slot clock generator 103 and the terminal information of the previous basic packet are obtained from the basic packet length counter 109.
[0054]
Next, when the broadcast of another node basic packet is issued during the counting of the slot gap of M in the judging section 119, M is incremented by +4, and the judging section 121 judges whether or not the M slots have been counted.
[0055]
When the determination result in the determination unit 119 is NO, the processing in the processing unit 120 is omitted and the process goes to the determination unit 121. When the determination result is NO, the process returns to the determination unit 119 and the M slots are counted. Wait until.
[0056]
When M slots are counted by the determination unit 121, the broadcast generation unit 122 starts a second round of broadcast relay. That is, a broadcast of BDR = 1, TCR = 0, and TMC = 1 is generated by the broadcast generation unit 122, and the transmission circuit 113 transmits the broadcast in the next slot.
[0057]
On the other hand, when the own node starts the broadcast relay, the broadcast generation unit 123 generates a broadcast with BDR = 1 and TCR = 1, and enters the 5-slot gap counting unit 126 in FIG.
[0058]
When the received broadcast is classified by the processing distribution unit 116 into a broadcast of BDR = 1 and TCR = 0, the auxiliary address is analyzed by the auxiliary address analysis unit 131. When the broadcast is all 1, it corresponds to the second and subsequent rounds. The determination unit 124 determines whether the stop condition is satisfied. If the determination result is YES, the processing within the scope of the present invention is terminated (125).
[0059]
When the determination result by the determination unit 124 is NO, the five-slot gap count unit 126 sets five slots to the slot gap count P, and then, in the determination unit 127, the basic packet is transmitted from another node until the P count is exhausted. Is determined, and if the result of the determination is YES, the processing unit 128 increments the count of P by 7, and then the determination unit 129 determines whether the P slot has been counted. If the determination result in the determination unit 129 is NO, the process returns to the determination unit 127. When the count of P is exhausted, the broadcast generation unit 130 generates a broadcast of BDR = 1 and transmits it from the transmission circuit 113. If the determination result in the determination unit 127 is NO, the processing unit 128 is skipped and the processing enters the determination unit 129. The case where the auxiliary address is other than all 1 in the auxiliary address analysis unit 131 will be described with reference to FIG.
[0060]
In the above embodiment, the slot gap is usually five slots, one slot is used for collision detection, and three slots are used for the first broadcast relay. However, the present invention is not limited to this, and the collision detection is best. It is essential to give priority to broadcast relay and give priority to broadcast relay, and the numbers 1 and 2 are not essential.
[0061]
The bit rate of the network is also 2 Mbps, the basic packet is 8 bytes, and the slot length is half of the basic packet length. However, the present invention is not limited to this, and the slot length is related to the network transmission delay. Make the maximum transmission delay between nodes in the network 20 times or more. In addition, the slot length is the same as the basic packet length, or a fraction thereof.
[0062]
As described above, even if the first-order broadcast relay is performed and the priority is controlled in the slot gap between the second and subsequent rounds, a collision may occur. At this time, it can be understood that a collision is detected by the collision detection unit 110 of FIG. 6 or that a command transmitted by the received command interpretation unit 114 causes a collision from another node. At that time, the same packet is retransmitted by setting 1 to the first bit of the control unit in FIG.
[0063]
The order of the timing control may be such that the existing addresses are arranged in a fixed order, and may be arranged not only in the direction of decreasing addresses but also in the direction of increasing addresses. When the order is m, counting from the next slot at the end of the previous packet, the (m + 3) th slot is set as the head slot of the node. If the next slot is assumed to be the first slot in order 1 on the premise of a two-slot gap, the first slot of the node in order m can be said to be the mth slot.
[0064]
Further, in the embodiments shown in FIGS. 6 and 7, an example has been described in which only basic packets are used, but the present invention is also effective for data packets (packets having three or more slots). That is, in the processing unit 120 of FIG. 6 and the processing unit 128 of FIG. 7, when another packet is inserted, M is set to +4 and P is set to +7. + (T + 2), and the processing unit 128 increases P by + (t + 5). Such processing is also included in the present invention.
[0065]
Further, as described in the above embodiment, the broadcast relay is also used when transmitting the command for securing the transmission right so that the related nodes do not interfere because the two nodes communicate with each other directly. FIG. 8 shows a configuration for that purpose.
[0066]
First, in the processing unit 132, one node (usually a transmitting node) that communicates with each other prepares a command for securing a transmission right by setting BDR = 1, TCR = 0, and broadcasting by designating a partner node with an auxiliary address. The three-slot gap counting unit 126, the determination unit 127, the processing unit 128, and the processing unit 129 control the slot gap.
[0067]
On the other hand, upon receiving such a broadcast relay, the processing distribution unit 116 in FIG. 6 enters the flow of BDR = 1 and TCR = 0, and the auxiliary address analysis unit 131 analyzes the auxiliary address. At this time, it is analyzed that the address is other than all 1, and if it is found that the own address is specified by the determination unit 133 in FIG. 8, the processing unit 134 prepares a normal broadcast of BDR = 0 and TCR = 0. Since this forms part of the broadcast relay, the priority is raised to a two-slot gap, a two-slot gap is prepared by the slot gap setting unit 135, and the slot gap control is performed by the determination unit 136, the processing unit 137, and the determination unit 138. Do. Then, the process returns to the transmission circuit 113 in FIG. In this way, the transmission right securing command reaches all nodes that can communicate directly with the two nodes.
[0068]
【The invention's effect】
As described above, according to the present invention, when broadcasting data for disseminating information to each node, the same data is further broadcast unless the node receiving the data satisfies the stop condition. And when the broadcast is requested, the timing of the broadcast performed by shifting the timing between the nodes is based on the transmission address of the received broadcast. When the next slot at the end of the previous broadcast is set as the first slot, the (m + 3) -th slot is transmitted first, and the broadcast is transmitted to the m-th node. Relatively small like a home network using In data communication of a stable network can be information one node transmits to receiving notifications to all nodes in the network.
[0069]
Also, according to the present invention, when broadcasting data for disseminating information to each node, a request is made to specify a specific node and repeat the broadcast transmission, and the requested node Since the broadcast transmission is repeated from the end of the broadcast packet with a smaller slot gap than that of a normal packet, information is delivered to all nodes that can directly communicate with the two nodes that are parties to data communication. Can be.
[Brief description of the drawings]
FIG. 1 is a diagram showing a slot and a basic packet transmission method applied to the present invention.
FIG. 2 is an explanatory diagram of a gap after receiving a basic packet.
FIG. 3 is a diagram showing a configuration of a basic packet.
FIG. 4 is a diagram illustrating a configuration of a control unit of a basic packet in FIG. 3;
FIG. 5 is an explanatory diagram of a process for assigning an order to all nodes based on a transmission address of a received broadcast;
FIG. 6 is a block diagram illustrating a configuration of an embodiment of the present invention.
FIG. 7 is a block diagram showing a configuration of the embodiment.
FIG. 8 is a block diagram showing a configuration of another embodiment of the present invention.
[Explanation of symbols]
A, B, C nodes
101 Basic clock generator
102 1/256 slot clock generator
103 Slot clock generator
104 receiving circuit
105 Basic packet receiving unit
106 Other receiver
107 Received signal detector
108 AND circuit (logical product)
109 Basic packet length count section
110 Collision detector
111 collision command generator
112 1 slot gap counting section
113 transmission circuit
114 Receive command interpreter
115 Judgment unit
116 processing distribution unit
117 Self address ordering section
118 Count set section
119 Judge
120 processing unit
121 Judgment unit
122, 123, 130 Broadcast generator

Claims (4)

In a data communication network using an indoor power line or wireless communication, the transmission time of a basic packet, which is a basic unit of data communication, is divided by n (n = 1, 2,...) At the timing of each node, and the division unit is defined as a slot. Slot clock generating means for generating a slot clock for use as a unit of transmission time,
Requesting means for requesting to further broadcast the same data when broadcasting data for disseminating information to each node, unless the node receiving the data satisfies a stop condition;
A timing instructing unit for instructing that the broadcast be performed with a timing shifted between nodes when requesting a broadcast in the requesting unit;
When there is an instruction to shift the timing between nodes, the order m is given to all nodes in a fixed order from the transmission address of the received broadcast based on the transmission address of the received broadcast, and the next slot at the end of the previous broadcast is set as the first slot. , When the (m + 3) -th slot is at the head and the broadcast is transmitted to the nodes in order m and there is no instruction to shift the timing between the nodes, the broadcast is started from the end of the previous broadcast. Transmitting means for transmitting at least 5 slots apart;
A data distribution method in data communication, comprising: 2. The data distribution method in data communication according to claim 1, wherein, in order to shift the timing between the nodes by the transmission means, while counting the leading slot for each node, a t slot length (t = 2. A data distribution method in data communication, comprising means for increasing the count value of the first slot by (t + 2) every time a packet of (2, 3, 4,...) Is transmitted. In a data communication network using an indoor power line or wireless communication, the transmission time of a basic packet, which is a basic unit of data communication, is divided by n (n = 1, 2,...) At the timing of each node, and the division unit is defined as a slot. Slot clock generating means for generating a slot clock for use as a unit of transmission time,
Requesting means for designating a specific node and requesting to repeat the broadcast transmission when broadcasting data for disseminating information to each node;
A node requested to repeat the broadcast transmission by the requesting means, from the end of the broadcast packet, a transmission means for starting the broadcast transmission to be repeated with a smaller slot gap than a normal packet,
A data distribution method in data communication, comprising: In the data distribution method in data communication according to claim 1, the fourth transmitting means comprises:
When there is an instruction to shift the timing between the nodes, when the next slot is the first slot, a packet of length t is transmitted starting from the {3m + 1 + t (m-1)} th slot to shift the timing. A data distribution method in data communication, characterized in that when there is no instruction, the broadcast is replaced by a transmitting means for transmitting the broadcast at least five slots away from the end of the previous broadcast packet.

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