JP6786404B2 - Transmitter, receiver, communication system and communication method - Google Patents

Description

The present invention relates to a communication technique performed via a plurality of channels formed in one communication medium.

In a communication system, for effective use of one communication medium, for example, a plurality of channels are provided in one communication medium by using a multiplexing technique. For example, Patent Document 1 discloses wavelength division multiplexing in which a plurality of signals having different wavelengths are multiplexed in one core of an optical fiber. In this case, one wavelength corresponds to one channel. Further, Patent Document 2 discloses polarization multiplexing in which optical signals having polarizations orthogonal to each other are transmitted by one optical fiber core. In this case, each polarization corresponds to one channel. Further, Patent Document 3 discloses mode multiplexing in which signals of different transmission modes are multiplexed on one optical fiber core. In this case, each transmission mode corresponds to one channel. Further, Patent Document 4 discloses a multi-core optical fiber in which a plurality of cores are provided in one optical fiber. When one core of a multi-core optical fiber transmits an optical signal carrying one data series, one core corresponds to one channel. Further, a multiplexed optical signal such as a wavelength division multiplexing signal can be input to each core of the multi-core optical fiber. In this case, each wavelength of each core corresponds to a channel.

Japanese Unexamined Patent Publication No. 2016-208100 Japanese Unexamined Patent Publication No. 2014-220822 Japanese Unexamined Patent Publication No. 2016-063372 JP-A-2016-09537

A plurality of channels formed on the same communication medium are treated as different transmission lines, but the quality of each channel may be different even if the channels are via the same communication medium. For example, four channels # 1, # 2, # 3 and # 4 are formed in one communication medium, transmission data A is transmitted on channel # 1, transmission data B is transmitted on channel # 2, and transmission data C is transmitted. Is transmitted on channel # 3, and transmission data D is transmitted on channel # 4. At this time, the quality of channels # 1 to # 3 is good, but if the quality of channel # 4 is poor, many errors may occur in the transmission data D.

The present invention is a transmission device and a reception device of a communication system in which a plurality of channels are formed and transmitted on one communication medium, and the difference in the quality of each channel affects the data transmitted by the communication system. It provides a transmitting device, a receiving device, a communication system, and a communication method capable of suppressing the above.

According to one aspect of the present invention, the transmitting device, each of which corresponds to the first generating means for generating two carrier signals carrying data, said two carrier signals to a predetermined transfer function 2 × 2 A second generation means for generating two transmission signals by converting based on a matrix is provided, and each of the two transmission signals is transmitted on different channels formed on the same communication medium, and the above-mentioned the corresponding 2 × 2 matrix transfer function, a different 2 × 2 matrix is an orthogonal matrix, regardless of the level of added noise to each of the two transmission signals, the noise to each of the two transmission signals The two signals obtained by converting the signal to which the above is added by the inverse matrix of the 2 × 2 matrix corresponding to the transfer function have the same level of noise added to each of the two transport signals. It is characterized by being determined to.

According to the present invention, it is possible to suppress the difference in the influence of the difference in quality of each channel on the data transmitted by the communication system.

The block diagram of the transmission device by one Embodiment. The block diagram of the receiving apparatus by one Embodiment. The block diagram of the transmission device by one Embodiment. The block diagram of the receiving apparatus by one Embodiment. The block diagram of the processing part by one Embodiment.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. The following embodiments are examples, and the present invention is not limited to the contents of the embodiments. Further, in each of the following figures, components not necessary for the description of the embodiment will be omitted from the drawings.

<First Embodiment>
Hereinafter, the number of channels formed in one communication medium will be described as 2, but those skilled in the art can apply the contents described in each of the following embodiments to the number of channels of 3 or more. Further, in the following description, two channels formed in one communication medium will be referred to as channel # 1 and channel # 2. Further, the number of data series to be transmitted is set to two, which is the same as the number of channels, and is described as transmission data A and B, respectively.

FIG. 1 is a configuration diagram of a transmission device according to the present embodiment. The transmission data A is input to the bit separation unit 11, and the transmission data B is input to the bit separation unit 12. The bit separation unit 11 separates the transmission data A bit by bit and outputs the data series A1 and A2. Similarly, the bit separation unit 12 separates the transmission data B for each bit and outputs the data series B1 and B2. The bit multiplexing unit 13 bit-multiplexes the input data sequences A1 and B1 and outputs the data sequence A1B1. Similarly, the bit multiplexing unit 14 bit-multiplexes the input data sequences A2 and B2 and outputs the data sequence A2B2. Based on the data series A1B1, the transmission unit 15 performs processing necessary for outputting a signal to channel # 1, such as modulation and amplification. Similarly, the transmission unit 16 performs processing necessary for outputting a signal to channel # 2, such as modulation and amplification, based on the data series A2B2. In addition, channel # 1 and channel # 2 are formed in one communication medium such as an optical fiber.

FIG. 2 is a configuration diagram of a receiving device according to the present embodiment. The receiving units 21 and 22 receive the signals transmitted to the channels # 1 and # 2, respectively by the transmitting device shown in FIG. 1, and perform processing such as demodulation. The receiving unit 21 outputs the data series A1B1, and the receiving unit 22 outputs the data series A2B2. The bit separation unit 23 separates the data series A1B1 for each bit and outputs the data series A1 and B1, respectively. Similarly, the bit separation unit 24 separates the data series A2B2 for each bit and outputs the data series A2 and B2, respectively. The bit multiplexing unit 25 bit-multiplexes the input data series A1 and A2, thereby outputting the transmission data A. Similarly, the bit multiplexing unit 26 bit-multiplexes the input data series B1 and B2, thereby outputting the transmission data B.

According to this embodiment, half of each bit of the transmission data A is transmitted on channel # 1, and the other half is transmitted on channel # 2. The same applies to the transmission data B. Therefore, the bit error rates of the transmission data A and the transmission data B are the same regardless of the difference in quality between the channel # 1 and the channel # 2. In the present embodiment, bit-by-bit separation and multiplexing are performed, but a configuration in which bit-by-bit separation / multiplexing may be performed, such as byte-by-byte separation / multiplexing.

<Second embodiment>
Subsequently, the second embodiment will be described focusing on the differences from the first embodiment. FIG. 3 is a configuration diagram of a transmission device according to the present embodiment. The transmission data A is input to the modulation unit 31, and the transmission data B is input to the modulation unit 32. The modulation unit 31 modulates with the transmission data A and outputs a signal A (conveyance signal) in the time domain. Similarly, the modulation unit 32 modulates with the transmission data B and outputs a signal B (conveyance signal) in the time domain. The modulation may be a single carrier system or a multi-carrier system such as OFDM. The processing unit 33 outputs signals C and D (transmission signals) in the time domain from signals A and B. Here, when the signals in the frequency domain of the signals A, B, C and D are expressed as Af, Bf, Cf and Df, the signals Af, Bf, Cf and Df have the following relationship.

H is a so-called transfer function.

The transmission unit 35 performs processing necessary for transmitting the signal C on the channel # 1, such as conversion to an optical signal and amplification. Similarly, the transmission unit 36 performs processing necessary for transmitting the signal D on the channel # 2, such as conversion to an optical signal and amplification.

FIG. 4 is a configuration diagram of a receiving device according to the present embodiment. The receiving units 41 and 42 receive the signals transmitted to the channels # 1 and # 2 by the transmitting device shown in FIG. 3, respectively, and perform processing such as conversion to an electric signal and amplification to output the signals C and D, respectively. Output. In reality, noise is superimposed on the signals transmitted on channels # 1 and # 2, respectively, so that the signals output by the receiving units 41 and 42 have noise components added to the signals C and D. .. However, here, it is described as an ideal state in which noise does not appear on channels # 1 and # 2, and the like. The processing unit 43 performs the reverse processing of the processing unit 33 in the transmission device to output the signal A and the signal B. Specifically, the processing unit 43 outputs the signal A and the signal B from the signal C and the signal D by the following equation.

The demodulation units 45 and 46 determine and output the transmission data A and B by demodulating the signals A and B, respectively.

The above description is for an ideal state in which noise does not appear on channels # 1 and # 2, but in reality, channels # 1 and # 2 each have different levels of noise. However, as is clear from equations (3) and (4), the noise generated in channel # 1 is distributed with an amplitude equal to that of signal A and signal B. Similarly, the noise generated in channel # 2 is distributed with an amplitude equal to that of signal A and signal B. That is, the noise levels added to the signals A and B are the same regardless of the difference in the noise levels added to the signals C and D by the transmission on the channels # 1 and 2. Therefore, it is possible to suppress the difference in the quality of the transmission data A and B output by the demodulation units 45 and 46, for example, the bit error rate.

It is necessary that the values of the signals C and D when the processing of the equation (3) in the processing unit 43 are output are simultaneously output by the processing unit 33. Therefore, although not shown in FIGS. 3 and 4, the processing unit 33 periodically inserts synchronization information into the signals C and D, and the processing unit 43 periodically inserts the synchronization information into the signals C and D, and the processing unit 43 bases the synchronization information on the signals C and D, respectively. Processing is performed by compensating for the difference in propagation delay between 1 and # 2.

In the above description, in the transmission device, the modulation units 31 and 32 output the signals A and B in the time domain, respectively, and the processing unit 33 converts the signals A and B into the signals Af and Bf in the frequency domain. Then, the signals Cf and Df in the frequency domain are generated by the transmission function H, and then the signals Cf and Df are converted into the signals C and D in the time domain. However, for example, the modulation units 31 and 32 output a signal in the frequency region, that is, a complex value indicating a position on the complex plane corresponding to the modulation symbol, and the processing unit 33 converts this complex value by the transfer function H. However, it may be configured to generate a signal in the time region based on the converted complex value. The same applies to the receiving device. In addition, for example, the modulation unit 31 and 32 and the processing unit 33 in the transmission device can be realized by, for example, a DSP (digital signal processor). Further, the demodulation units 45 and 46 and the processing unit 43 in the receiving device can also be realized by, for example, a DSP (digital signal processor).

Further, the processing by the processing units 33 and 43 can be performed not in the digital area by the DSP but in the analog area. FIG. 5 shows a configuration for realizing the processing unit 33 in the analog region. The branching portions 51 and 52 branch signals A and B, respectively, and output signals A1 and A2, and signals B1 and B2. The signals A, A1 and A2 have the same signal waveform. Similarly, signals B, B1 and B2 have the same signal waveform. The amplitude phase adjusting units 53, 54, 55, 56 adjust the amplitude and phase of the signals A1, A2, B1 and B2 according to the transfer function H. After that, the combine unit 57 combines the signals A1 and B1 to output the signal C, and the combine unit 58 combines the signals A2 and B2 to output the signal D. The same applies to the processing unit 43, and the signals A and C in FIG. 5 may be exchanged, the signals B and D may be exchanged, and the transfer function H may be read as its inverse matrix H- ¹ .

Further, the process of generating the signals C and D from the signals A and B can also be performed in the optical domain instead of the analog electrical domain shown in FIG. In this case, after converting the signal A and the signal B into optical signals, the same processing as described in the analog region may be performed.

As described above, in the present embodiment, in the transmission device, the nth transport signal (n is an integer of 2 or more) is generated from the first transport signal that carries data, and each of the first transport signal to the nth transport signal is generated. The nth transmission signal is generated from the first transmission signal by adjusting the amplitude and phase and synthesizing. Then, the nth transmission signal from the first transmission signal is transmitted via each of the n channels formed in the same communication medium. The amplitude of each of the first carrier signal to the nth carrier signal is adjusted by multiplying each of the first carrier signal to the nth carrier signal by the amplitude adjustment coefficient. For example, in the equations (1) and (2), the amplitudes of the first carrier signal (signal A) and the second carrier signal (signal B) are each multiplied by √ (1/2), and the amplitude adjustment coefficient is √ (1). / 2). Similarly, the phase of each of the first carrier signal to the nth carrier signal is adjusted by shifting the phase of each of the first carrier signal to the nth carrier signal by a predetermined value. In the equations (1) and (2), the phase shift amount is 0 or π / 2. The receiving device generates the nth carrier signal from the first carrier signal by adjusting and synthesizing the amplitude and phase of each of the nth transmit signal from the first transmit signal. At this time, the receiving device adjusts the amplitude of each of the first transmission signal to the nth transmission signal by multiplying each of the first transmission signal to the nth transmission signal by the amplitude adjustment coefficient, similarly to the transmission device. In the equations (3) and (4), the amplitude adjustment coefficient is √ (1/2). Therefore, the noise generated in each channel is equally distributed to each carrier signal, and thus the amount of noise on each carrier signal is substantially equal. In the above embodiment, the amplitude adjustment coefficient multiplied by each transport signal is made equal in the transmission device, but it may be different for each transport signal. However, the difference in the amplitude adjustment coefficient for each carrier signal shall be a predetermined value (threshold value) or less. The same applies to the receiving device. In this case, the noise on each carrier signal generated by the receiving device is not equal, but by setting the difference in amplitude adjustment coefficient to a predetermined value (threshold value) or less, the difference in noise on each carrier signal generated by the receiving device can be reduced. It can be within a predetermined range.

31, 32: Modulation unit, 33, 43: Processing unit, 35, 36: Transmission unit, 41, 42: Receiver unit, 45, 46: Demodulation unit

Claims (7)

Each a first generating means for generating two carrier signals carrying data,
A second generation means that generates two transmission signals by converting the two transfer signals based on a 2 × 2 matrix corresponding to a predetermined transfer function.
Is equipped with
Each of the two transmission signals is transmitted on different channels formed on the same communication medium.
2 × 2 matrix corresponding to the transfer function is a different 2 × 2 matrix is an orthogonal matrix, regardless of the level of added noise to each of the two transmission signals, to each of the two transmission signals The two signals obtained by converting the noise-added signal by the inverse matrix of the 2 × 2 matrix corresponding to the transfer function are obtained by adding the same level of noise to each of the two transport signals. A transmitter characterized by being determined in the same manner. The corresponding 2 × 2 matrix before Symbol transfer function,
The transmitting device according to claim 1, wherein the transmission device is characterized by the above. A receiver for receiving two received signals,
The two received signals are transmitted by transmitting each of the two transmitted signals on different channels formed on the same communication medium.
The two transmission signals are those each of which is generated by converting on the basis of the corresponding 2 × 2 matrix into two carrier signal a predetermined transfer function to carry data,
The receiving apparatus includes a generating means for generating two received carrier signal by converting, based the two received signals to the inverse of the corresponding 2 × 2 matrix in the transfer function,
A determination means for determining data to be conveyed by each of the two transfer signals based on the two received transfer signals, and
With
2 × 2 matrix corresponding to the transfer function is a different 2 × 2 matrix is an orthogonal matrix, regardless of the level of the two transmission signal noise added to each of the two received carrier signal , The receiving device, characterized in that it is determined so that the same level of noise is added to the two carrier signals. The corresponding 2 × 2 matrix before Symbol transfer function,
The receiving device according to claim 3, wherein the receiving device is characterized by the above. A communication system including a transmitting apparatus and a receiving apparatus communicating via two channels formed in the same communication medium,
The transmitter is
A first generating means that generates two transport signals, each carrying data,
A second generation means that generates two transmission signals by converting the two transfer signals based on a 2 × 2 matrix corresponding to a predetermined transfer function.
Transmitting means for transmitting the two transmission signals, to said two channels,
Is equipped with
The receiving device is
A third generation means for generating two reception transfer signals by converting the two reception signals received via the two channels based on the inverse matrix of the 2 × 2 matrix corresponding to the transfer function.
A determination means for determining data to be conveyed by each of the two transfer signals based on the two received transfer signals, and
Is equipped with
2 × 2 matrix corresponding to the transfer function is a different 2 × 2 matrix is an orthogonal matrix, regardless of the level of the two transmission signal noise added to each of the two received carrier signal , A communication system characterized in that it is determined so that the same level of noise is added to the two carrier signals. The corresponding 2 × 2 matrix before Symbol transfer function,
The communication system according to claim 5, wherein the communication system is characterized by the above. A transmitting apparatus and a receiving apparatus, a communication method for communicating via two channels formed in the same communication medium,
A first generation step in which the transmitter generates two transport signals, each of which carries data, and
A second generation step in which the transmission device generates two transmission signals by converting the two transfer signals based on a 2 × 2 matrix corresponding to a predetermined transfer function.
A transmission step in which the transmission device transmits the two transmission signals to the two channels,
A third generation step of generating two received transport signals by converting the two received signals received via the two channels based on the inverse matrix of the 2 × 2 matrix corresponding to the transfer function.
A determination step in which the receiving device determines data to be conveyed by each of the two received and conveyed signals based on the two received and conveyed signals.
Including
2 × 2 matrix corresponding to the transfer function is a different 2 × 2 matrix is an orthogonal matrix, regardless of the level of the two transmission signal noise added to each of the two received carrier signal , A communication method characterized in that it is determined so that the same level of noise is added to the two transport signals.