Communication system

Abstract

To allow data that should be transmitted to be transmitted through another channel, while overflow is being avoided, if one channel becomes unusable in a communication system capable of multiplex communication.SOLUTION: A communication system uses a first channel and a second channel, and includes a transmitter and a receiver. The transmitter sends the receiver N1-bit first raw data, which is a binary representation of a first numerical value, via the first channel, and sends the receiver N2-bit second raw data, which is a binary representation of a second numerical value, via the second channel. If the first channel is unavailable, the transmitter sends (N1-M1)-bit first coarse data, obtained by dropping lower M1 bits of the first raw data, and (N2-M2)-bit second coarse data, obtained by dropping lower M2 bits of the second raw data, via the second channel. The receiver reconstructs the data by adding M1 bits of zeros to the lower side of the (N1-M1)-bit first coarse data and adding M2 bits of zeros to the lower side of the (N2-M2)-bit second coarse data.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a communication system including a transmitter that transmits data that has been binarized into a numerical value, and a receiver that receives the data. [Background technology]

[0002] For example, a communication system is known that binarizes and transmits / receives numerical values ​​representing physical quantities such as voltage and current (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-15991 Summary of the Invention [Problem to be solved by the invention]

[0004] In communication systems, transmitters and receivers may use multiple channels to send and receive data. This technology is called multiplexing, and by sending data over different frequency bands or in different time periods over a single physical transmission path, it becomes possible to transmit large amounts of data.

[0005] If one channel becomes unavailable for some reason, it would be convenient if data that should be sent through that channel could be sent through another channel. However, when data that should be sent through multiple channels is sent through one channel, there is a risk that the amount of data to be sent will exceed the capacity of the available channel (i.e., overflow will occur). This specification provides a technology that, in a communication system capable of multiplexed communication, when one channel becomes unavailable, transmits data that should be sent through the unavailable channel through another channel while avoiding overflow. [Means for solving the problem]

[0006] The communication system disclosed in this specification is a communication system that communicates using a first channel and a second channel and includes a transmitter and a receiver. The transmitter uses the first channel to send N1-bit first-based data obtained by binarizing a first numerical value, and uses the second channel to send N2-bit second-based data obtained by binarizing a second numerical value. The receiver receives the first and second data and restores them to the first and second numerical values, respectively. If the first channel is unavailable, the transmitter uses the second channel to send (N1-M1)-bit first coarsened data obtained by dropping the least significant M1 bits of the first data, and (N2-M2)-bit second coarsened data obtained by dropping the least significant M2 bits of the second data. The receiver adds M1 bits of zeros to the lower-order side of the received (N1-M1)-bit first coarse-grained data to restore a first numerical value with the lower-order M1 bits of the numerical value truncated, and adds M2 bits of zeros to the lower-order side of the received (N2-M2)-bit second coarse-grained data to restore a second numerical value with the lower-order M2 bits of the numerical value truncated.

[0007] In the communication system disclosed in this specification, when data that should be sent over multiple channels is sent over a single channel, the least significant digits of the numeric data are dropped to shorten the number of data bits. For example, when sending 8-bit numeric data over each of two channels, shortening the numeric data to 4 bits prevents overflow when sending two pieces of numeric data over a single channel. In the communication system disclosed in this specification, if one channel becomes unavailable, the data that should be sent over the unavailable channel can be transmitted over another channel while avoiding overflow.

[0008] Details and further improvements of the technology disclosed in this specification are described in the following "Description of Embodiments of the Invention." [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a functional block diagram of a communication system according to an embodiment (when two channels are available). [Figure 2] 10A and 10B are diagrams illustrating bit number reduction processing and bit number restoration processing. [Figure 3] FIG. 2 is a functional block diagram of a communication system according to an embodiment (when the first channel is unavailable). DETAILED DESCRIPTION OF THE INVENTION

[0010] A communication system 2 according to an embodiment will be described with reference to the drawings. The communication system 2 is composed of a transmitter 10 and a receiver 20. The transmitter 10 is capable of not only transmitting data but also performing various processes, and the receiver 20 is capable of not only receiving data but also performing various processes. For example, the communication system 2 is mounted on an electric vehicle, the transmitter 10 is part of a controller (overall controller) that manages the entire driving system of the electric vehicle, and the receiver 20 is part of a controller (motor controller) that controls the electric motor for driving. Numerical data indicating the accelerator opening and the amount of brake depression are sent from the overall controller to the motor controller. In this embodiment, the focus is on the transmission and reception of data, and therefore the terms "transmitter 10" and "receiver 20" are used.

[0011] FIG. 1 shows a functional block diagram of a communication system 2. The transmitter 10 includes functions 1, 2, 3, and 4 that generate predetermined numerical values. Functions 1-4 may, for example, be functions that output numerical data of measurements from a temperature sensor or a current sensor, or functions that output numerical data indicating the accelerator opening of an electric vehicle. Function 1 generates numerical values ​​a1 and a2, and function 2 generates numerical value a3. Function 3 generates numerical values ​​b1 and b2, and function 4 generates numerical value b3.

[0012] The receiver 20 has a function 5 that uses the numerical values ​​a1, a2, and a3, and a function 6 that uses the numerical values ​​b1, b2, and b3. The transmitter 10 has a communication channel that sends the numerical values ​​to the receiver 20. The communication system 2 (transmitter 10 and receiver 20) can use multiplex communication, and can send numerical values ​​simultaneously on multiple channels (first and second channels). The transmitter 10 and receiver 20 are physically connected by a single transmission line. The first and second channels are in different frequency bands, so the first and second channels can be used simultaneously. The first and second channels may be multiplex communication types that use a single transmission line in a time-division manner.

[0013] The transmitter 10 comprises a first transmitting unit 11 that uses the first channel and a second transmitting unit 12 that uses the second channel, and the receiver 20 comprises a first receiving unit 21 that uses the first channel and a second receiving unit 22 that uses the second channel. In Fig. 1, the first channel and the second channel are drawn with separate lines, but as mentioned above, the first channel and the second channel are physically realized by a single transmission line.

[0014] Function 1 of the transmitter 10 sends the generated numerical values ​​a1 and a2 to the first transmitting unit 11. Function 2 sends the generated numerical value a3 to the first transmitting unit 11. Function 3 sends the generated numerical values ​​b1 and b2 to the second transmitting unit 12. Function 4 sends the generated numerical value b3 to the second transmitting unit 12. The first transmitting unit 11 simultaneously sends the numerical values ​​a1, a2, and a3 to the first receiving unit 21 using the first channel. The second transmitting unit 12 simultaneously sends the numerical values ​​b1, b2, and b3 to the second receiving unit 22 using the second channel. The numerical values ​​a1, a2, a3, b1, b2, and b3 are simultaneously sent from the transmitter 10 to the receiver 20. The first receiving unit 21 sends the received numerical values ​​a1, a2, and a3 to function 5, and the second receiving unit 22 sends the received numerical values ​​b1, b2, and b3 to function 6.

[0015] The following describes the process when the first channel becomes unusable due to some kind of malfunction. Assume that the numerical value a3 generated by function 2 is a numerical value with an auxiliary role, and that failure to reach function 5 (receiver 20) will not result in a serious malfunction. However, failure to reach function 5 for the other numerical values ​​a1 and a2 will result in a serious malfunction. When the first channel becomes unusable, communication system 2 can use the second channel to send the numerical values ​​a1 and a2 to function 5 of receiver 20. However, the data size of the numerical values ​​a1 and a2, as well as the numerical values ​​b1, b2, and b3, is too large to transmit simultaneously over the first channel. Therefore, communication system 2 reduces the total data size of the numerical values ​​a1, a2, b1, b2, and b3, and transmits them from transmitter 10 to receiver 20. The receiver 20 restores the received data to its original data size and passes the restored data to each function.

[0016] In this embodiment, the process of reducing the data size of original data is called bit count reduction process, and the process of restoring the data size is called bit count restoration process. Figure 2 shows a diagram for explaining bit count reduction process and bit count restoration process. For example, assume that the data size of the original data is 8 bits. The transmitter 10 drops the lowest 3 bits of the original data to create data of (8 - 3) = 5 bits. This is the bit count reduction process. The data from which the number of bits of the original data has been reduced is called coarse-grained data.

[0017] The transmitter 10 sends the coarse data to the receiver 20. The receiver 20 adds three zero bits to the least significant side of the received coarse data to restore the original 8-bit data. This is the bit restoration process. Since the least significant three bits of the restored data are zero, the value is the original data with the least significant three bits truncated.

[0018] The original data subjected to the bit reduction and bit restoration processes has a fixed-point data format, with the least significant bit corresponding to the resolution of the physical quantity that should be represented. For example, consider a case where original data A has an 8-bit data size, with 1 bit representing voltage (V) with a resolution of 0.25 (V). If the numeric value of original data A is "11011011," this original data A is expressed as A = 219 in decimal notation, which, when converted to the original voltage, is 219 × 0.25 = 54.75 (V). By discarding the lowest three bits of original data A, the 5-bit coarse data "11011" is generated. The transmitter 10 sends the coarse data to the receiver 20. The receiver 20 restores the original 8-bit data by adding zeros to the lowest three bits of the received 5-bit coarse data ("11011"). The restored 8-bit data is "11011000," which is "216" in decimal. When this number is converted to the original voltage, it becomes 216 x 0.25 = 54.00 [Volts]. The restored data A (= 54.00) is equivalent to the original data A (= 54.75 volts) with the decimal points truncated and discarded.

[0019] In the bit reduction and restoration processes described above, the restored data always has the lowest three bits set to zero, so the smallest unit is "1000." The smallest unit of the original data is "0001," which corresponds to 0.25 volts in physical quantity. In binarization, "1000" corresponds to "8" in decimal, which corresponds to 8 x 0.25 = 2 volts. In other words, the restored data has a resolution that is 3 bits lower than the original data. Although the resolution is lower, the necessary data is sent from the transmitter 10 to the receiver 20.

[0020] FIG. 3 shows a block diagram of the communication system 2 when the first channel is unavailable. Assume that the original numerical values ​​a1, a2, a3, b1, b2, and b3 are fixed-point 8-bit data. As mentioned above, the numerical value a3 is auxiliary data, so the numerical values ​​a1 and a2 are the data to be sent to the receiver 20, and the numerical values ​​b1, b2, and b3 are also the data to be sent to the receiver 20. The transmitter 10 performs bit number reduction processing 13 on the 8-bit numerical values ​​a1, a2, b1, and b2. In the bit number reduction processing 13, the lowest 4 bits of the original data are removed to generate coarse data. The data size of the coarse data is 4 bits.

[0021] Data b1 and b2 were originally sent on the second channel. The total number of bits of the original data b1 and b2 is 8 bits x 2 = 16 bits. The total number of bits of the data obtained by coarsening the four original data a1, a2, b1, and b2 is 4 bits x 4 = 16 bits. The data obtained by coarsening the four original data a1, a2, b1, and b2 can be sent using the number of bits required to send the original data b1 and b2.

[0022] 1 and 3, the length of the numerical box represents the data length. In Fig. 3, the data size of the original data a1, a2, b1, and b2 in Fig. 1 is halved, and the original data b3 is the same as in Fig. 1. In this case, if the original data a1, a2, b1, and b2 are coarsened, the original data b3 can be sent to the receiver 20 using the second channel without being coarsened.

[0023] The coarsened data of the original data a1, a2, b1, and b2, and the original data b3, are received by the receiver 20 via the second channel. At the receiver 20, the coarsened original data a1, a2, b1, and b2 are subjected to a bit number restoration process 23, and the restored data in which zeros are substituted for the lowest four bits of each of the original data a1, a2, b1, and b2 is sent to each function. In this case, at the receiver 20, data whose resolution has been coarsened from the original 1 bit to 4 bits (i.e., data that has been coarsened 16 times) is sent to each function. The numerical value b3 is sent to function 6 with its original resolution intact.

[0024] In this way, in the communication system 2, if the first channel becomes unavailable, the necessary data can be sent from the transmitter 10 to the receiver 20 using the second channel, although the numerical resolution will be coarser.

[0025] In the example shown in Figure 3, the data size of the numbers a1, a2, b1, and b2 has been reduced to half of the original size through bit reduction processing. When the first channel becomes unavailable, how much the numbers are reduced depends on the number of numbers to be transmitted, the data size of each number, and the capacity (data transfer rate) of the second channel.

[0026] The technology of the embodiment can be expressed in generalized symbols for the number of bits of original data and the number of bits to be reduced as follows: When two communication channels are available, a numerical value transmitted by a transmitter through a first channel is referred to as first original data, and a numerical value transmitted through a second channel is referred to as second original data. The first original data is a numerical value represented in fixed-point format and is binary data of N1 bits. The second original data is a numerical value represented in fixed-point format and is binary data of N2 bits. The receiver receives the first original data through the first channel and the second original data through the second channel.

[0027] If the first channel is unavailable, the transmitter sends the first coarse-grained data of (N1-M1) bits, which is obtained by dropping the least significant M1 bits of the first original data, and the second coarse-grained data of (N2-M2) bits, which is obtained by dropping the least significant M2 bits of the second original data, on the second channel. As mentioned above, the numbers M1 and M2 are determined depending on the number and size of the original data to be sent, and the communication speed of the second channel. However, there are limitations on the numbers M1 and M2, and they cannot be less than 0. <M1<N1、および、0≦M2<N2である。

[0028] The receiver adds M1 bits of zeros to the least significant side of the received (N1-M1)-bit first coarsened data to restore the first original data with the least significant M1 bits of numerical value truncated. The receiver also adds M2 bits of zeros to the least significant side of the received (N2-M2)-bit second coarsened data to restore the second original data with the least significant M2 bits of numerical value truncated.

[0029] One unit of the original data to be sent (the LSB of the original data) corresponds to the minimum resolution of the physical quantity (for example, voltage or current value) that the value indicates. The resolution of the first original data restored by the bit number restoration process is the resolution of the original first original data × (the value obtained by expressing M1 bits as a decimal number), and the resolution of the restored second original data is the resolution of the original second original data × (the value obtained by expressing M2 bits as a decimal number).

[0030] In the communication system 2 of the embodiment, when data that should be sent over multiple channels is sent over one channel, the lower-order digits of the numerical data are dropped to shorten the number of data bits. For example, when sending 8-bit numerical data over each of two channels, shortening the numerical data to 4 bits prevents overflow even when sending two numerical data over one channel. If one channel becomes unavailable, the communication system 2 can transmit the data that should be sent over the unavailable channel over another channel while avoiding overflow.

[0031] Points to note regarding the technology described in the embodiment will be described. A transmitter 10 of a communication system 2 of the embodiment generates numerical values ​​a1-a3 and b1-b3 to be sent to a receiver 20. The transmitter 10 sends the numerical values ​​a1-a3 to the receiver 20 using a first channel, and sends the numerical values ​​b1-b3 to the receiver 20 using a second channel. The numerical values ​​a1 and a2 generated by the transmitter 10 correspond to an example of a first numerical value that is the basis of the first base data. The numerical values ​​b1 and b2 generated by the transmitter 10 correspond to an example of a second numerical value that is the basis of the second base data.

[0032] If the second channel is unavailable and the first channel is available, the original first channel may be referred to as the second channel and the original second channel may be referred to as the first channel.

[0033] In the communication system of the embodiment, the transmitter and receiver have two communication channels. The technology disclosed in this specification can be applied to a communication system having three or more communication channels. For example, in a communication system having three communication channels, if a first channel is unavailable, one piece of data that should be transmitted through the first channel may be transmitted through a second channel, and another piece of data that should be transmitted through the first channel may be transmitted through a third channel. In this case, the processing of the embodiment is performed on the numerical data transmitted and received through the second channel, and the same processing is also performed on the numerical data transmitted and received through the third channel.

[0034] Furthermore, each of the multiple communication channels may be controlled by an independent CPU (Central Processing Unit).

[0035] Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives alone is technically useful. [Explanation of symbols]

[0036] 2: Communication system 10: Transmitter 11: First transmitting unit 12: Second transmitting unit 13: Bit number reduction processing 20: Receiver 21: First receiving unit 22: Second receiving unit 23: Bit number restoration processing

Claims

[Claim 1] A communication system that performs communication using a first channel and a second channel, a transmitter that transmits N1-bit first elemental data obtained by binarizing a first numerical value over a first channel, and transmits N2-bit second elemental data obtained by binarizing a second numerical value over a second channel; a receiver that receives the first original data and the second original data and restores them to the first numerical value and the second numerical value, respectively; and if the first channel is unavailable, the transmitter transmits, via a second channel, first coarsened data of (N1-M1) bits obtained by dropping the least significant M1 bits of the first original data and second coarsened data of (N2-M2) bits obtained by dropping the least significant M2 bits of the second original data; The receiver adds M1 bits of zeros to the lower-order side of the received (N1-M1)-bit first coarse-grained data to restore the first numerical value with the lower-order M1 bits of the numerical value truncated, and adds M2 bits of zeros to the lower-order side of the received (N2-M2)-bit second coarse-grained data to restore the second numerical value with the lower-order M2 bits of the numerical value truncated. Communication system.

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