KR20070091510A - The multiplexing method of communication channel - Google Patents

Abstract

A method and a system for multiplexing communication channels provided to apply to a non-multiplex interface, interface various devices with a minimized change of a communication program, and cause no communication confusion even if a transfer rate is dynamically changed in the multipoint network. Information is modulated in a predetermined modulation more according to a transfer target when the information of the device is transferred to a common bus. Modulated output is sequentially output and a modulated signal is compared with the signal of the common bus(430). Competition is canceled or continued depending on a comparison result. The number of combinations of information expression is discriminated or expanded by determining a high priority device irrespective of the transfer rate by cutting off the output to the common bus from the device when the signal sequentially output from the devices is different from the signal of the common bus(460).

Description

Communication channel multiplexing method and system {The Multiplexing method of communication channel}

1 is a point-to-point transmission method by a conventional individual line

2 is a block diagram of a multichannel embodiment of the present invention.

Figure 3 bus arbitration unit of the present invention

4 is a flowchart of the serial arbitration principle by the sequential comparison method

[Figure 5] Serial Arbitration Contention Table When Eight Nodes with 4 Bit Identification Address Participate in Contention

6 is an embodiment of a multi-channel of the present invention

7 illustrates an arbitration and communication band of the present invention

The present invention has been developed to multiplex non-multiplexed device 10 interfaces, or to multiplex between multiple devices.

Multiplexing in a communication system is a means for facilitating communication between a plurality of communication nodes and simplifying a physical transmission path. Multiplexing is classified into circuit switched and packet switched. The technique of the present invention corresponds to a distributed circuit switched scheme. Here, the decentralization of arbitration mechanism has the effect of minimizing irregular changes in switching topology due to additional change of nodes and making it possible to expand in a batch manner.

Typically, the point-to-point approach is not designed to physically connect multiple devices. Designed without multiplexing, point-to-point topologies are very limited in their connection methods and cumbersome, requiring physical manipulations when changing interface devices, which cannot be controlled by software alone. In the point-to-point method, when a communication device is configured using a switching element, a switching device can be physically connected to a single bus by selectively establishing only a connection of a specific device (a set of transmitting and receiving devices) at a specific time. The present invention uses a method of selecting a target of a connection by using the common bus (1) arbitration technology of the present invention in an existing communication channel. A typical high speed communication channel mainly uses a high frequency band to have a high bandwidth. In this case, the low frequency band is not used. By using this feature, if the unused band is transmitted through the bus arbitration signal, it is possible to transmit a signal required for multiplexing without changing the existing communication channel. Means of band separation may be needed to avoid the expected signal interference in realizing this technique.

By configuring the channel switching to be controlled by the arbitration signal, multiple devices can be randomly connected by software operation. In other words, the mediation technology allows the connection to be determined.

In the communication system of the present invention, a method using a separate frequency band is used to transmit the arbitration information. The present invention can implement an interface between multiple devices without additional lines on any network, but requires a distributed arbitration circuit and change the network interface of each node.

As computer systems and networks become more complex and the amount of distributed or parallel processing increases, the method of transmission has a significant impact on the structure and design of the system. In order to implement an efficient network, the method of transmitting arbitration information is important. Since common resources of a system are connected by a communication channel or a communication bus, bus arbitration and communication method are very important as a method of allocating bus licenses among competing nodes (devices) to use the same resources.

In a computer system, there are several buses of various stages for transferring information between each node (or processor), and each processor of the multiprocessor system accesses another node through the common bus system. A bus is a communication path connecting two or more nodes, a bus used for communication between components and a bus used for communication between different processing systems located at a remote place in a network.

Point-to-point technology avoids bus collisions without a separate software protocol. Electrical signal collisions are inevitable. Since all the control signals such as the arbitration signal must be defined in the packet, a strict software protocol definition is involved. The present invention is characterized in that the multiplexing is possible without changing the packet containing the node identification information according to the multiplexing of the existing communication channel. This function is implemented by using different bands of communication information and arbitration information.

The existing point-to-point approach is inherently incapable of multiple access and random expansion.

The present invention is directed to a communication system having multiple devices:

1) a solution through frequency band separation for transmitting a communication signal and an arbitration signal between a plurality of separate lines or a plurality of devices in a minimum transmission path without additional software protocol for transmitting an arbitration signal;

2) implementation of common bus (1) arbitration technology to prevent collisions between arbitration signals of common bus (1);

3) a common bus (1) arbitration for preventing transmission of signals and a method of extending a transmission code for direct transmission to a plurality of arbitrary devices using a minimum transmission path without a plurality of individual lines or additional software protocols;

4) cancel a higher protocol simplification effect to simplify the complicated communication procedure for transmitting the arbitration signal, and devise means for accessing resources of the communication counterpart node only by connection of the physical layer;

5) Implement on existing transmission path without additional transmission path so that it can be applied to existing non-multi-interface technology.

The present invention aims to implement a multiple interface technology between multiple devices designed to be non-multiple. If the distributed mediation technology is used for the existing point-to-point communication technology, it can be controlled by various methods such as centralized or distributed control, so that the router design or the non-network device can be applied to the network.

2 shows the information transmission resource sharing relationship among multiple devices. The present invention can share a device among devices connected to all buses regardless of the number of nodes [FIG. 2]. In other words, a form of a switched network is configured. 2 is an embodiment in which the mediation and the communication can be changed without affecting each other by using the distributed mediation apparatus 40 separated from the communication channel.

According to the present invention, each communication device is connected to a common bus via a switch 30 so as to receive information through the common bus. Here, the band filter 20 may be used to prevent interference of the arbitration signal and the communication signal. If more than two nodes want to occupy the common bus, signal collisions are involved, so that only the device selected by the arbitration circuit 40 separately configured can access the common bus.

In the present invention, the distributed arbitration method is capable of common bus arbitration without arbitration failure, and in general, since the arbitration time is relatively very short compared to the communication time, there is no practical problem even if the arbitration signal is not high speed.

1) Distributed Serial Arbitration

3 is an embodiment of a distributed arbitration by self-decision method and apparatus based on priority in a multipoint network having a serial bus structure. When each node participating in the bus license contention has a bus arbitration circuit, the common bus 1 is assigned a license to the highest priority node by a distributed arbitration method. Bus arbitration according to the present invention can be implemented using only a single bus arbitration line (i.e., common bus 1). You can also get information about which nodes get bus usage rights from the common bus.

3 is a basic block diagram of an embodiment of a serial arbitration apparatus according to the present invention.

The serial arbitration apparatus of a multipoint network according to the present invention is connected to a multipoint on a common bus and serializes a serial unit (310) for converting a bit stream (Bit Stream) 321 into serial transmission information and the serial output. A modulator 320 for modulating 321 to a transmission clock, a comparison unit 350 for detecting and controlling a signal mismatch by comparing its output signal 331 with the bus signal 1 (Comparison Unit 350) and an arbitration controller ( 340 (Arbitration Control Unit) and a bus interface unit 330 (Bus Interface) for inputting the bit stream 381 to perform a wired OR operation.

The serialization unit 310 is composed of a shift register for converting bit streams 321 into serial information.

The comparator 350 detects a mismatch between its output signal 331 and the common bus signal 1, and outputs a contention withdrawal signal 341. The arbitration control unit starts arbitration with the mediation start signal 341 and withdraws the contention with the contention withdrawal signal 341. This arbitration start signal 341 is advantageous in attempting to start a race when the bus is inactive in order to prevent the bus state from becoming unstable even at the slightest time during a bus collision.

The bus interface unit 330 is configured as an OR type channel (Open Collector), and this output activates the common bus 1 only when logic '1' is applied to the control input.

When the arbitrator according to the present invention is used in combination with a flow chart, a contention table and a timing chart, the operation and the mediation method will be described in more detail.

Referring to FIG. 3, the bus intermediator is composed of three logic circuits of a serializer 310, a comparator 350, an arbitration controller 340, and a bus interface 330 on a common bus 1.

The serial unit 310 serially outputs transmission information to the modulator 320 one bit at a time by requesting the common bus 1 to use the common bus 1. The output of the arbitration controller 340 and the comparator 350 is output. Limited by (Disable, Inhibit).

The arbitration control unit 350 is set by the arbitration start signal 341 to enable the serialization unit and sequentially output the bitstream 331 modulated onto the common bus 1 via the bus interface unit 330. The comparator 350 compares the modulated bitstream 331 with the bus signal 1 via the buffer, and if it does not match, resets the arbitration controller 340 to prohibit serial output to the common bus 1. .

The bus interface unit 350 includes a bus driver 382 for mounting the output 331 of the modulator 320 on the common bus 1. The bus driver 330 is a tri-state buffer of open-collector type for activating the common bus 1, and the logical sum of all bits of the identification addresses of all nodes is OR. It outputs the result of to the common bus (1).

In the above process, an OR operation is used to select a large value of the identification address as a high priority, and an AND operation is used to select a small value of the identification address as a high priority.

4 is a flowchart illustrating a priority serial mediation method according to the present invention. According to the arbiter 300 according to the present invention, FIG. 5 is a contention table for selecting a node having the highest priority when eight nodes having a 4-bit identification address participate in contention.

The operation of the arbiter according to the present invention will be described with reference to Figs. 3, 4 and 5. All bus arbiters of each node connected on a multipoint network have the same structure and operate on the same principle.

In step 410 (a contention target setting step), the arbitration control register 346 is set by the bus use arbitration start signal 301 to start contention of bus usage rights. The output 343 of the arbitration control register 340 determines whether to participate in contention, and the serialization unit 310 sequentially outputs each bit.

In step 420 (logical operation step), when using an arbitration method for giving the highest priority to the node having the largest transmission information, the bus driver 330 causes the common bus 1 to be wired ORed. Therefore, in the common bus 1, the logical sum of the identification address signals output from all nodes is shown.

In step 430 (comparison determination step), the bit stream 331 of the information output from the serializer 310 to the common bus 1 through the modulator 320 appears on the common bus 1. Compare the signals. In this process, when the two signals do not coincide with each other, there are two cases (S03 and S04) as shown in Table 1. One is the case where the output signal 331 is a logic value '0' and the signal appearing on the common bus 1 is a logic value '1' to the common bus 1 (S03). At this time, an identification address output from the node If the value of is smaller than information output from another node, the arbitration control register 340 is reset by step 470 since it must be withdrawn from contention for obtaining the common bus 1 license. When the arbitration control register 340 is reset, the bus activation operation is disabled and thus serial output is inhibited and the corresponding node is excluded from the contention cycle. Another case (S04) is a case where the logic value '1' of the common bus 1 driver outputted to the common bus 1 and the signal appearing on the common bus 1 are the logic value '0', in this case (S04). ) Is the case where an error occurs in the common bus line. In the present invention, when an abnormality occurs in the track of the common bus 1, it is to be excluded from the contention cycle afterwards, and if necessary, a separate process can be taken. After the mediation operation according to the bus driver control signal and the signal of the common bus 1 is explained in detail after the next step explanation, the node that is not withdrawn from the contention goes to the next step 440.

In step 440 (termination check step), it is determined whether all contention processes have been completed, and if not, proceeds to step 450 in order to participate in the next contention, outputs the next bit, and then proceeds to step 420. Will be repeated. If the contention process is completed for all the bits until the end without dropping in the middle of the contention process, the license of the common bus 1 is obtained. The common bus (1) has a characteristic that the arbitration information shown in the contention process is sequentially displayed.

TABLE 1 is a truth table showing the arbitration operation. The following is a review of all cases that may occur according to the output control signal 343 and the signal of the common bus 1 of each node. Arbitrators 300 of the present invention are connected to the input and output terminals of the bus in a multi-point on one serial common bus (1), the operation is made in parallel. Therefore, the actions of all intermediaries are not independent and are related to each other. The truth table is shown in Table 1. The contention control register 340 of each node according to the correlated information of all nodes shown in the common bus 1 and the arbitration control unit 340 serial bit stream 321 to determine the next operation of each node by the association. The state of is divided into bits and the output of the contention control register 340 according to each state is examined through the truth table in Table 1 as follows. To describe the symbols used in Table 1, ACU (t) is the output logic value 343 of the current contention control register 340, B is the bus driver logic value 331, and BUS is the common bus 1's value. The logical value ACU (t + 1) is the logical value of the state following the contention control unit 340.

TABLE 1

The behavior of the arbiter at each node is shown in Table 1 as shown in Table 1.

State S01 is the initial value ACU (t) = 0 of the contention control unit 340, so there is no contention request and is not a contention target.

In the states S02, S03, S04, and S05, since the initial value is ACU (t) = 1, there is a request for arbitration. The operation is as follows.

In the state S02, when the bus driver input 331 B = 0 is in an inactive state, the common bus 1 is not activated with BUS = 0 so that the inconsistency signal is not detected by the comparator 350 so that the next arbitration process is performed. Proceed.

Since the state S03 is the bus driver input 331 B = 0 of its own and BUS = 1, when the bus is activated when it is not activated, the node having a higher priority than the common bus is assigned to the common bus (1). ) Is activated when the priority is low, so that the contention control unit 340 is reset and excluded from the contention process.

State S04 is a case where the bus signal 1 is logic '0' when its modulated output 331 is logic '1' and thus cannot occur in a normal bus driver interface situation. Since the bus driver 330 or the common bus 1 has a problem, the electrical signal transmission is in a normal state, so that the arbitration control unit 340 is reset so that it no longer participates in contention, and if necessary, a separate action may be taken.

In the state S05, since its output 331 is a logic '1' and the bus signal 1 is also a logic '1', it matches its output, so that not only itself but also another node outputs a logic '1' on the bus. As he continues to compete in contention. (At this time, the other node that outputs 0 (in the condition of S01 and S02) has a low priority regardless of which node, so the contention control unit 340 is reset to prevent participation in contention anymore.)

As shown in FIG. 5, in the first comparison process, three nodes withdraw contention and a logical value '1' appears in the common bus 1 (519). In the second comparison process, the two nodes withdraw the contention (512, 514) and the logical value '1' appears in the common bus (1). In the third comparison process, no node withdraws the contention (520) and the logical value '0' appears in the common bus (1). In the last comparison process, two nodes withdraw the contention (511, 518) and logical value '1' appears on the common bus (1), and node S6 participates in contention until the last bit, so the license of the common bus (1) is acquired. (516). In addition, the sequential information appearing on the common bus 1 is " 1101 " as shown in 519, which is the same as the output value of the identification address of the node S6 516, indicating that the node S6 has the highest priority.

FIG. 6A is a contention timing diagram of the present invention when transmission speeds of the nodes are different from each other, in which contention is started from the contention start time 11, and a node having a late response time is relatively low in priority and dropped out first. When two or more nodes respond, contention is achieved by the binary value of the identification address.

Features of the transmission method using the distributed mediation technology of the present invention are as follows.

The present invention enables the role of a Distributed Multiplexer-Demultiplexer wired on a serial line.

Common bus arbitration is possible without changing the software protocol of the communication device. In addition, modulation methods such as Manchester and NRZ can eliminate the initial information that can occur during link and demodulation and preamble by software method to minimize link overhead.

The present invention uses a break pulse that activates a bus longer than the minimum transmission rate specified in the communication system, so that even a node currently using the common bus (1) can return resources and enter into contention. It is possible to synchronize the contention times of all nodes that want to use the common bus (1).

Therefore, if all nodes are waited by the break pulse and then the contention address is repetitive after the idle time proportional to the transmission speed of each node has elapsed, all the nodes can be used without using a special binary pattern. The node may participate in the acquisition of the common bus 1 regardless of whether the common bus 1 is currently used.

Therefore, the node which wants to use the common bus 1 can request the use of the common bus 1 at any time. In other words, it is possible to make a request to use the common bus 1 in real time in any situation, and extract the information of the licensed node from the arbitration information displayed on the common bus 1 in the arbitration process. Pulse interrupt requests are also possible in serial multipoint networks.

The arbiter according to the present invention identifies the priority by the size of the identification address and allocates the right of use of the common bus 1 to any node in the network. Therefore, if each node outputs the data to be transmitted continuously after the identification address, data communication between nodes in the network is also possible without using a separate bus.

In the arbitration method according to the present invention, the identification addresses are sequentially output to the common bus 1, and the common bus signal 1 is again fed back, compared, and compared to be excluded from contention if they do not match. How to identify priority. Here, the criterion of agreement for identifying the highest priority is regarded as the same signal when the timing of change of the logic state between the comparison targets is coincident even when the logic state is reversed.

In the present invention, if the signal appearing on the common bus 1 is not its own signal, the logical state is used as a criterion for determining whether to cancel the contention.

According to an embodiment of the common bus 1 arbitration unit of the present invention, a modulation unit is included between the serialization unit and the bus interface unit so as to ensure smooth communication at a wide range of transmission speeds. A method of arbitrating multiple nodes on a network, which is characterized by the adoption of a synchronous method, is also provided.

In addition, according to an embodiment of the present invention, there is provided a method of including in a special pattern on one bus without a separate dedicated control line. The method of the present invention is capable of arbitration and communication at the same time by at least two serial lines, which is advantageous in terms of scalability, but requires some time for the extraction process of the synchronization signal separation.

In addition, according to an embodiment of the present invention, the synchronization signal sharing method uses the data rate of the lowest node (lower limit of communication rate) as an arbitration start signal when nodes having different transmission rates are interconnected. If you activate the bus longer than the time slot, it can not be regarded as a normal communication signal, so you can use this as a synchronization signal to synchronize all nodes at the start of arbitration without using a special binary signal pattern. Nodes requiring arbitration without the addition of a method are provided for arbitrating the bus by emitting an arbitration / communication start pulse to the common bus whenever necessary.

If the above method is applied not only for arbitration but also for data transmission in multi-point serial bus, the channel which is judged to be difficult to transmit normally in multiple access situation is abandoned. By securing other bypass channels, it can at least prevent communication failures caused by bus collisions, thus ensuring the maximum reliability of transmissions.By using this feature, if data are separated by bits in a single communication process and communicated through the secured bus, the transmission rate per unit time Can be improved.

According to Boolean Algebra or De Morgan's theorem, since logic functions are dual, many variations can be derived by implementing or expressing the concept of the present invention by changing the positive logic to negative logic, but these are considered to be the same as the concept of the present invention. For example, in the bus combining method, the addition of NOT to the OR operation is replaced with the AND operation, or the OR operation is converted to the negative logic, so that the AND operation is performed. In addition, when the physical function is the same and only the means or elements of implementation are different, for example, a bus driver may be used as an electrical device such as a tri-state buffer, a transistor, a FET, or a switching device. It is well known that it is possible to change the bus into a different physical energy or change the bus into a wired or wireless channel, and thus, a separate description is omitted.

The present invention can be applied to multiple systems as well as a multipoint network. A plurality of pieces of information can be transmitted in a division scheme according to the carrier type of the present invention. According to the present invention, arbitration technology can arbitrarily determine the connection target, so that router design or non-network device can be applied to networking.

Although the above-described embodiments of the present invention have described a case in which a specific number of nodes contend, the present invention is not limited thereto, and the present invention is not limited thereto, but the type of transmission medium, the selection of an implementation element, the definition of an identification code, and a modulation scheme It will be apparent that there may be various variations according to this.

The present invention relates to an extension method for separating and transmitting data and arbitration information to a minimum transmission line in a communication system. The present invention relates to an extension of multiple interfaces.

1. Applicable to existing non-multiple interfaces;

2. Allows various devices to interface even with minimal changes to existing communication protocols;

3. Communication confusion does not occur even if the transmission speed is dynamically changed in the multipoint network;

4. Since the signal collision of the common bus 1 does not occur, the bus utilization rate can be increased by eliminating unnecessary time until communication is stabilized at the time of Data Link;

5. It is possible without arbitration confusion without changing the separate software communication protocol, and the system configuration is simpler than the conventional technology, so that multiplexing is possible without changing the complicated communication protocol.

The present invention can be applied to various communication schemes without fundamentally changing each communication channel. By integrating the arbitration device into a single semiconductor chip, multiple devices can be easily connected simply by connecting to the bus, and a wide range of practical applications are expected. In modern computer and electronic technology where downsizing and flexibility are important, it may be usefully used as an interface between multiple devices.

Claims (2)

A method of multiplexing channels by separating communication and common bus arbitration in a communication system with a common bus. In a multipoint network in which a plurality of devices are connected to a common bus, in a bus right arbitration to prevent a signal collision of the common bus by logically calculating a signal output from the devices in the common bus: (1) modulating the information of the device on a common bus by a predetermined modulation method according to a transmission target; (2) sequentially outputting the modulated output; (3) comparing the modulated signal with a signal of a common bus; (4) withdrawing or continuing the contention according to the comparison result; (5) By comparing the signals outputted sequentially by the devices and the signals of the common bus, and when they are different from each other, the devices having the highest priority are determined regardless of the transmission speed by cutting off the output to the common bus. The arbitration information transmission method of classifying and extending the number of combinations of information representations.

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