CN107925479B - Signal processing method, device and system - Google Patents
Signal processing method, device and system Download PDFInfo
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- CN107925479B CN107925479B CN201680049153.2A CN201680049153A CN107925479B CN 107925479 B CN107925479 B CN 107925479B CN 201680049153 A CN201680049153 A CN 201680049153A CN 107925479 B CN107925479 B CN 107925479B
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- H04—ELECTRIC COMMUNICATION TECHNIQUE
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Abstract
The embodiment of the invention provides a signal processing method, a signal processing device and a signal processing system, relates to the field of communication, and can reduce the bandwidth of a signal sent by sending end equipment and reduce the system cost. The signal processing method comprises the following steps: the communication equipment acquires a first symbol sequence to be transmitted, wherein the level number of the first symbol sequence is M, and M is more than or equal to 2; the communication equipment delays a first symbol sequence to be transmitted by N first symbol periods to generate a second symbol sequence, wherein the first symbol period is the time length between any two adjacent symbols in the first symbol sequence, and N is more than or equal to 1; the communication equipment determines a third symbol sequence according to the first symbol sequence and the second symbol sequence to be transmitted, wherein the bandwidth of the third symbol sequence is smaller than that of the first symbol sequence to be transmitted; and D/A conversion is carried out on the third symbol sequence by the communication equipment, a first analog signal is generated, and the first analog signal is sent.
Description
Technical Field
The present invention relates to the field of communications, and in particular, to a method, an apparatus, and a system for processing a signal.
background
with the continuous development of communication technology, short-distance optical communication systems have also come into high-speed development. In a short-distance optical communication system, in order to implement high-speed large-capacity transmission, a transmitting end device generally modulates a symbol sequence to be transmitted by using a Direct Detection (DD) technique.
In general, a sending end device in a short-distance optical communication system mainly modulates a symbol sequence to be transmitted by using a PAM4(Four-level Pulse Amplitude Modulation) technique to generate a modulated symbol sequence. After the modulated symbol sequence is subjected to a series of processing such as digital-to-analog conversion, electro-optical signal conversion and the like, the transmitting terminal equipment transmits the processed signal to the opposite terminal equipment. However, the modulated symbol sequence generated by the PAM4 technique has a large bandwidth, so that the signal transmitted by the transmitting end device has poor dispersion resistance when transmitted in a standard single-mode optical fiber channel.
Currently, to reduce the bandwidth of a modulated symbol sequence, a transmitting end device filters the modulated symbol sequence by using an RRC (Root Raised Cosine) filter that carries at least 3 taps to reduce the bandwidth of the modulated symbol sequence. The RRC filter can realize different filtering effects by adjusting the tap coefficients, the more taps the RRC filter carries, the better the filtering effect is, and the smaller the bandwidth of the symbol sequence processed by the RCC filter is. However, as the number of taps increases, the implementation structure of RRC becomes more complex and the cost becomes higher accordingly.
Disclosure of Invention
embodiments of the present invention provide a signal processing method, apparatus, and system, which reduce bandwidth of a signal sent by a sending end device and reduce system cost.
in order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:
The embodiment of the invention provides a precoder, which comprises a delay unit and a processing unit connected with the delay unit.
Specifically, the delay unit is configured to receive a first symbol sequence, delay the first symbol sequence by N first symbol periods to generate a second symbol sequence, and send the second symbol sequence to the processing unit, where the number of levels of the first symbol sequence is M, the first symbol period is a time length between any two adjacent symbols in the first symbol sequence, N is greater than or equal to 1, and M is greater than or equal to 2.
Specifically, the processing unit is configured to receive the first symbol sequence and the second symbol sequence sent by the delay unit, generate a third symbol sequence according to the first symbol sequence and the second symbol sequence, and send the third symbol sequence, where a bandwidth of the third symbol sequence is smaller than a bandwidth of the first symbol sequence.
In the embodiment of the invention, the level number of the first symbol sequence received by the precoder is M, and M is more than or equal to 2, namely the first symbol sequence is a multi-level symbol sequence, the fluctuation change of the first symbol sequence is severe, the precoder generates the second symbol sequence through the time delay of the first symbol sequence, and determines the third symbol sequence according to the first symbol sequence and the second sequence number sequence, so that the fluctuation change of the first symbol sequence can be effectively reduced, the fluctuation change of the third symbol sequence is slow, and the bandwidth of the third symbol sequence is smaller than that of the first symbol sequence.
Further, the processing unit comprises an adding subunit and a sending subunit, the adding subunit is connected with the delay unit, and the adding subunit is connected with the sending subunit; wherein the content of the first and second substances,
The adding subunit is configured to receive the first symbol sequence and the second symbol sequence sent by the delay unit, and add the first symbol sequence and the second symbol sequence to obtain a third symbol sequence;
And the transmitting subunit is configured to transmit the third symbol sequence obtained by the adding subunit.
Another embodiment of the present invention provides a communication device, which includes a signal generator, a symbol modulator connected to the signal generator, and a digital-to-analog converter, a precoder connected to both the symbol modulator and the digital-to-analog converter.
Specifically, the signal generator is configured to generate a bit sequence to be transmitted, and send the bit sequence to be transmitted to the symbol modulator.
Specifically, the symbol modulator is configured to receive the bit sequence to be transmitted sent by the signal generator, modulate the bit sequence to be transmitted in a preset pulse amplitude modulation manner to generate a first symbol sequence, and send the first symbol sequence to the precoder, where the number of levels of the first symbol sequence is M, and M is greater than or equal to 2.
Specifically, the precoder is configured to receive the first symbol sequence sent by the symbol modulator, encode the first symbol sequence to generate a third symbol sequence, and send the third symbol sequence to the digital-to-analog converter, where a bandwidth of the third symbol sequence is smaller than a bandwidth of the first symbol sequence.
Specifically, the digital-to-analog converter is configured to receive the third symbol sequence sent by the precoder, perform digital-to-analog conversion on the third symbol sequence, generate a first analog signal, and send the first analog signal.
The communication device provided by the embodiment of the present invention includes the precoder described in the previous embodiment, and after the communication device generates the bit sequence to be transmitted and tunes the bit sequence to be transmitted to the first symbol sequence, the communication device encodes the first symbol sequence by using the precoder to generate a third symbol sequence whose bandwidth is smaller than that of the first symbol sequence, and the reduction of the bandwidth of the third symbol sequence reduces the bandwidth of the signal sent by the communication device, thereby reducing the bandwidth of the signal sent by the communication device, reducing the cost of the communication device, and reducing the influence of chromatic dispersion on the signal sent by the communication device.
Further, the communication device further comprises an optical modulator connected with the digital-to-analog converter.
The optical modulator is configured to receive a first analog signal sent by the digital-to-analog converter, convert the first analog signal into an optical signal, and send the optical signal through an optical fiber channel.
Another embodiment of the present invention provides a signal processing method, where after obtaining a first symbol sequence to be transmitted with a level number of M, a communication device delays the first symbol sequence to be transmitted for N first symbol periods to generate a second symbol sequence, where the first symbol period is a time length between any two adjacent symbols in the first symbol sequence, N is greater than or equal to 1, and M is greater than or equal to 2, then the communication device determines a third symbol sequence according to the first symbol sequence to be transmitted and the second symbol sequence, where a bandwidth of the third symbol sequence is smaller than a bandwidth of the first symbol sequence to be transmitted, and finally, the communication device performs digital-to-analog conversion on the third symbol sequence to generate a first analog signal and sends the first analog signal.
The communication device in the embodiment of the present invention corresponds to the communication device described in the previous embodiment, and after obtaining the first symbol sequence to be transmitted, the communication device encodes the first symbol sequence by using the precoder to generate a third symbol sequence having a bandwidth smaller than that of the first symbol sequence, and the reduction of the bandwidth of the third symbol sequence reduces the bandwidth of the signal sent by the communication device, thereby achieving the reduction of the bandwidth of the signal sent by the communication device, reducing the cost of the communication device, and reducing the influence of chromatic dispersion on the signal sent by the communication device.
further, the determining, by the communication device, a third symbol sequence according to the first symbol sequence to be transmitted and the second symbol sequence specifically includes: and the communication equipment adds the first symbol sequence to be transmitted and the second symbol sequence to obtain the third symbol sequence.
Further, the obtaining, by the communication device, the first symbol sequence to be transmitted specifically includes: the communication equipment generates a bit sequence to be transmitted; and the communication equipment modulates the bit sequence to be transmitted by adopting a preset pulse amplitude modulation mode to obtain the first symbol sequence to be transmitted.
Further, the communicating transmits the first analog signal, comprising: the communication device converts the first analog signal to an optical signal and transmits the optical signal via a fiber channel.
another embodiment of the present invention provides a signal processing system, including the communication device according to any one of the foregoing embodiments and a receiving end device corresponding to the communication device, where the communication device is a sending end device, and the communication device and the receiving end device are connected by an optical fiber.
specifically, the receiving end device is configured to receive an optical signal sent by the communication device, perform optical-to-electrical conversion on the optical signal to generate a second analog signal, perform analog-to-digital conversion on the second analog signal to generate a fourth symbol sequence, and perform decoding processing and equalization processing on the fourth symbol sequence to generate a fifth symbol sequence.
The technical effects of the signal processing system provided by the embodiment of the present invention may refer to the technical effects of the communication device described in the signal processing method executed by the communication device in the above embodiments, and are not described herein again.
further, the receiving end device is specifically configured to delay the fourth symbol sequence by K second symbol periods to generate a sixth symbol sequence, add the fourth symbol sequence and the sixth symbol sequence to obtain a seventh symbol sequence, and perform equalization processing on the seventh symbol sequence to generate the fifth symbol sequence.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is apparent that the drawings in the following description are only some embodiments of the present invention.
fig. 1 is a schematic structural diagram of a conventional short-range optical communication system;
Fig. 2 is a spectrum diagram of a symbol sequence to be transmitted in a conventional short-range communication system;
Fig. 3 is a schematic structural diagram of a short-range optical communication system including RRC;
Fig. 4 is a first schematic structural diagram of a precoder according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a precoder according to an embodiment of the present invention;
Fig. 6 is a first schematic structural diagram of a communication device according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a communication device according to an embodiment of the present invention;
Fig. 8 is a schematic flowchart of a signal processing method according to an embodiment of the present invention;
FIG. 9 is a spectrum diagram of a third symbol sequence according to an embodiment of the present invention;
fig. 10 is a schematic structural diagram of a short-range optical communication system according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
The terms "first," "second," "third," and "fourth," etc. in the description and claims of the invention and the above-described drawings are used for distinguishing between different objects and not for limiting a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.
In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, interfaces, techniques, etc., in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known mobile devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
In addition, the term "and/or" herein is only one kind of association relationship describing an associated object, and means that there may be three kinds of relationships, for example, a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
As shown in fig. 1, in the conventional short-distance optical communication system, the transmitting end device includes a PAM4 sequencer, a DAC (Digital To Analog Converter) and a laser, and the receiving end device includes a PD (Photo Diode), an ADC (Analog To Digital Converter) and a decision equalizer.
The sender device generates a bit sequence { b1, b 2.. bn.. b2n } to be transmitted, where n is a positive integer. The PAM4 sequencer modulates { b1, b2,. bn,. b2n } by using PAM4 technique, and generates symbol sequences { I1, I2,. In } to be transmitted with 4 different levels, wherein, the input signal and the output signal of the PAM4 sequencer have the following relations:
I＝2*b+2*b；1≤k≤n
the PAM4 sequencer sends the generated symbol sequence { I1, I2.. In } to be transmitted to the DAC, the DAC converts { I1, I2.. In } into an analog signal D (t), and sends D (t) to the laser. After receiving the analog signal d (t), the laser modulates the optical modulation of the analog signal d (t) to generate an optical signal, and couples the generated optical signal into an optical fiber channel for transmission.
after receiving end equipment receives an optical signal sent by sending end equipment, a photodiode firstly converts the received optical signal into an effective electrical signal R (t), and sends R (t) to an ADC, the ADC performs analog-to-digital conversion on R (t) to generate a symbol sequence { v '1, v' 2.. v 'n }, or to say, the ADC samples R (t) according to a certain sampling frequency to generate a symbol sequence { v' 1, v '2.. v' n }, and after the ADC generates the symbol sequence { v '1, v' 2.. v 'n }, the ADC transmits the symbol sequence { v' 1, v '2.. v' n } to an equalizer for decision, and the decision equalizer performs equalization on { v '1, v' 2.. v 'n }, and decides and outputs a final receiving sequence { I' 1, I '2.. I' n }.
when the sending-end equipment sends a bit sequence to be transmitted, a PAM4 technology is adopted to modulate { b1, b2,. b.. bn,. b2n } to generate a symbol sequence { I1, I2,. In } to be transmitted, and the numerical value of the bandwidth of the symbol sequence is equal to the numerical value of the symbol rate. In order to realize high-speed transmission, the symbol rate In the near-field optical communication system is mostly high, and therefore, the bandwidth of the symbol sequence { I1, I2.. In } to be transmitted, which is generated by adopting the PAM4 technology, is also large.
For example, the symbol rate of the symbol sequence { I1, I2.. In } to be transmitted is 25Gbs, i.e., gigabits per second, and fig. 2 shows a spectral diagram of the symbol sequence { I1, I2.. In } to be transmitted. In fig. 2, the horizontal axis represents the frequency f, and the vertical axis represents the logarithm (Magnitude) of the amplitude. As can be seen from fig. 2, the main lobe bandwidth of the symbol sequence { I1, I2.. In } to be transmitted is 25GHz, i.e., the value of the main lobe bandwidth of the symbol sequence { I1, I2.. In } to be transmitted is equal to the value of the symbol rate of the symbol sequence { I1, I2.. In } to be transmitted.
The bandwidth of the symbol sequence { I1, I2.. In } to be transmitted is large, so that the anti-dispersion capability of a signal sent by sending end equipment is poor when the signal is transmitted In a standard single-mode optical fiber channel, and after the signal sent by the sending end equipment is transmitted for a certain distance, the influence of dispersion on the signal is serious, so that the signal is distorted, and the error rate is large.
In addition, because the bandwidth of the symbol sequence { I1, I2.. In } to be transmitted is large, a device capable of supporting a larger bandwidth is required to transmit the modulated symbol sequence, and the larger the bandwidth supported by the device, the higher the cost thereof, so that the cost of the system is increased.
In the existing short distance optical communication system, the bandwidth of the devices used in the system is severely insufficient in relation to the bandwidth of the signal due to the limitation of the system cost. Therefore, at the transmitting end device, the bandwidth of the signal transmitted by the transmitting end device can be reduced by adopting a spectrum compression technology.
In the prior art, In order to reduce the bandwidth of the symbol sequence { I1, I2.. In } to be transmitted, the transmitting end device pre-processes the symbol sequence { I1, I2.. In } to be transmitted by using an RRC filter carrying at least 3 taps.
The processing of the sequence of symbols to be transmitted I1, I2.. In } by the RRC filter is a filtering process. The RRC filter can achieve different filtering effects by changing tap coefficients of the RRC filter, that is, different tap coefficients of the RRC filter can make bandwidths of symbol sequences { I1, I2.. In } to be transmitted different. The filtering process of the RRC filter on the symbol sequence to be transmitted { I1, I2.. In } is also a wideband compression process of the RRC filter on the symbol sequence to be transmitted { I1, I2.. In }.
Specifically, with reference to fig. 1, as shown In fig. 3, after generating a symbol sequence { I1, I2,. In } to be transmitted, the PAM4 sequencer sends the symbol sequence { I1, I2,. In } to be transmitted to the RRC filter, and the RRC filter performs filtering processing on the symbol sequence { I1, I2,. In } to be transmitted, so as to generate a symbol sequence, where an input signal and an output signal of the RRC filter have the following relationships:
The RRC filter sends the symbol sequence it generates to the DAC, which converts it to an analog signal d (t) and sends d (t) to the laser. After receiving the analog signal d (t), the laser modulates the optical modulation of the analog signal d (t) to generate an optical signal, and couples the generated optical signal into an optical fiber channel for transmission.
The symbol sequence { I1, I2.. In } to be transmitted is subjected to bandwidth compression processing by an RRC filter, and the bandwidth of the symbol sequence is smaller than that of the symbol sequence { I1, I2.. In } to be transmitted, so that the requirement of a signal on the system bandwidth can be met. However, the implementation structure of RRC is very complex, and at least 3 taps with different coefficients are required, and the cost of the system is higher along with the complexity of the implementation structure.
In order to solve the above problem, embodiments of the present invention provide a signal processing method, apparatus, and system, where a sending end device performs delay superposition processing on a sequence signal to be transmitted, so as to reduce a bandwidth of a signal sent by the sending end device, and a receiving end device receives the signal sent by the sending end device, and then only needs to perform delay superposition processing on the received signal, so as to obtain a signal that is actually transmitted by the sending end device, so that a requirement of the signal sent by the sending end device on the bandwidth of the device can be reduced.
Example one
An embodiment of the present invention provides a precoder 100, and as shown in fig. 4, the precoder 100 includes a delay unit 10 and a processing unit 11 connected to the delay unit 10.
specifically, the delay unit 10 is configured to receive a first symbol sequence, delay the first symbol sequence by N first symbol periods to generate a second symbol sequence, and send the second symbol sequence to the processing unit, where the number of levels of the first symbol sequence is M, the first symbol period is a time length between any two adjacent symbols in the first symbol sequence, N is greater than or equal to 1, and M is greater than or equal to 2.
The processing unit 11 is configured to receive the first symbol sequence and the second symbol sequence sent by the delay unit 10, generate a third symbol sequence according to the first symbol sequence and the second symbol sequence, and send the third symbol sequence, where a bandwidth of the third symbol sequence is smaller than a bandwidth of the first symbol sequence.
Further, as shown in fig. 5, the processing unit 11 in the precoder 100 according to the embodiment of the present invention includes an adding subunit 11a and a transmitting subunit 11b, where the adding subunit 11a is connected to both the transmitting subunit 11b and the delay unit 10.
specifically, the adding subunit 11a is configured to receive the first symbol sequence and the second symbol sequence sent by the delay unit 10, and add the first symbol sequence and the second symbol sequence to obtain a third symbol sequence.
The transmitting subunit 11b is configured to transmit the third symbol sequence obtained by the adding subunit 11 a.
It should be noted that, in the embodiment of the present invention, the sub-unit for generating the third symbol sequence by the processing unit 11 according to the first symbol sequence and the second symbol sequence is not limited to the adding sub-unit 11b, and may be any other sub-unit capable of implementing the function, for example, a multiplying sub-unit.
It should be understood that the delay unit 10 provided in the embodiment of the present invention may include a receiving subunit, a delay processing subunit, and a sending subunit, or may be a module that integrates functions of the delay unit 10, and the embodiment of the present invention is not limited in particular.
In the embodiment of the invention, the number of the levels of the first symbol sequence received by the precoder is M, and M is more than or equal to 2, i.e., the first symbol sequence is a multi-level symbol sequence, the fluctuation of the first symbol sequence is relatively severe, and the frequency spectrum distribution of the first symbol sequence is dispersed, the precoder generates a second symbol sequence by delaying the first symbol sequence, and the first symbol sequence and the second sequence number sequence are added to obtain a third symbol sequence, the fluctuation of the third symbol sequence obtained after the first symbol sequence is processed by adopting the mode is slow, correspondingly, the frequency spectrum of the third symbol sequence is concentrated, the bandwidth of the third symbol sequence is smaller than the bandwidth of the first symbol sequence, that is, the precoder provided by the embodiment of the present invention can effectively reduce the bandwidth of the first symbol sequence by processing the first symbol sequence.
Example two
the communication device 110 according to the embodiment of the present invention includes the precoder described in the first embodiment, and as shown in fig. 6, the communication device 110 includes a signal generator 20, a symbol modulator 21 connected to the signal generator 20, a precoder 22 connected to the symbol modulator 21, and a digital-to-analog converter 23 connected to the precoder 22.
Specifically, the signal generator 20 is configured to generate a bit sequence to be transmitted, and send the bit sequence to be transmitted to the symbol modulator 21.
Specifically, the symbol modulator 21 is configured to receive the bit sequence to be transmitted sent by the signal generator 20, modulate the bit sequence to be transmitted in a preset pulse amplitude modulation manner to generate a first symbol sequence, and send the first symbol sequence to the precoder 22, where the number of levels of the first symbol sequence is M, and M is greater than or equal to 2.
The preset pulse amplitude modulation method may be PAM4, PAM6, or any other multi-level PAM, which is not specifically limited in this embodiment of the present invention.
Specifically, the precoder 22 is configured to receive the first symbol sequence sent by the symbol modulator 21, encode the first symbol sequence to generate a third symbol sequence, and send the third symbol sequence to the digital-to-analog converter 23, where a bandwidth of the third symbol sequence is smaller than a bandwidth of the first symbol sequence.
Here, the precoder 22 is the same as the precoder 100 in embodiment one.
The digital-to-analog converter 23 is configured to receive the third symbol sequence sent by the precoder 22, perform digital-to-analog conversion on the third symbol sequence, generate a first analog signal, and send the first analog signal.
further, in conjunction with fig. 6, as shown in fig. 7, the communication device 110 further includes an optical modulator 24 connected to the digital-to-analog converter 23.
the optical modulator 24 is configured to receive the first analog signal sent by the digital-to-analog converter 23, convert the first analog signal into an optical signal, and send the optical signal through an optical fiber channel.
Preferably, the optical modulator 24 in the present embodiment is a laser.
After the communication device generates the bit sequence to be transmitted and transfers the bit sequence to be transmitted to the first symbol sequence, the communication device encodes the first symbol sequence by using the precoder to generate a third symbol sequence with a bandwidth smaller than that of the first symbol sequence, and the bandwidth of the signal sent by the communication device is reduced by reducing the bandwidth of the third symbol sequence, so that the bandwidth of the signal sent by the communication device is reduced, the cost of the communication device is reduced, and the influence of chromatic dispersion on the signal sent by the communication device is reduced.
EXAMPLE III
The embodiment of the invention provides a signal processing method, which is applied to a communication system comprising the communication equipment and corresponding receiving end equipment. The communication device is a sending-end device, and the schematic structural diagram of the communication device may refer to fig. 6 and 7.
As shown in fig. 8, the signal processing method includes:
S101, the communication equipment obtains a first symbol sequence with M levels to be transmitted, wherein M is larger than or equal to 2.
Specifically, the method for the communication device to obtain the first symbol sequence to be transmitted in the embodiment of the present invention is: after the communication equipment generates the bit sequence to be transmitted, the communication equipment modulates the bit sequence to be transmitted by adopting a preset pulse amplitude modulation mode to generate a first symbol sequence to be transmitted.
The preset pulse amplitude modulation method in the embodiment of the present invention may be PAM4, PAM6, or any other multi-level PAM, which is not specifically limited in this embodiment of the present invention.
Illustratively, the communication device generates a bit sequence to be transmitted as { b1, b2,. bn,. b2n }, where n is a positive integer. The communication device modulates the bit sequence to be transmitted { b1, b2,. bn,. b2n } by using PAM4 technology, and generates a first symbol sequence to be transmitted { I1, I2,. In }.
the method for the communication device to obtain the first symbol sequence to be transmitted in the embodiment of the present invention is the same as the method for the sending end device to obtain the symbol sequence to be transmitted in the prior art, and details are not repeated here.
S102, the communication equipment delays the first symbol sequence to be transmitted by N first symbol periods to generate a second symbol sequence.
The first symbol period is the time length between any two adjacent symbols in the first symbol sequence, and N is larger than or equal to 1.
Preferably, the communication device in the embodiment of the present invention delays the first symbol sequence to be transmitted by one first symbol period, and generates the second symbol sequence.
S103, the communication equipment generates a third symbol sequence according to the first symbol sequence and the second symbol sequence to be transmitted, wherein the bandwidth of the third symbol sequence is smaller than that of the first symbol sequence to be transmitted.
Specifically, the communication device adds the first symbol sequence to be transmitted and the second symbol sequence to obtain a third symbol sequence.
preferably, the communication device in the embodiment of the present invention delays the first symbol sequence to be transmitted by one first symbol period, and generates the second symbol sequence.
Illustratively, the first symbol sequence to be transmitted is represented as: d [ k ] ═ Ik; k is more than or equal to 1 and less than or equal to n, the first symbol period T, and the communication equipment sets d [ k ] to Ik; a second symbol sequence generated by delaying k ≦ 1 ≦ n for one symbol period is denoted as d [ k-1] ═ Ik-1; k is 1. ltoreq. n, the third symbol sequence generated by the communication device may be represented as 1. ltoreq. k.ltoreq.n.
If I0 is assumed to be 0, the third symbol sequence is:
The number of levels of the first symbol sequence acquired by the communication equipment in the embodiment of the invention is M, and M is more than or equal to 2, i.e., the first symbol sequence is a multi-level symbol sequence, the fluctuation of the first symbol sequence is relatively severe, and the spectral distribution of the first symbol sequence is comparatively dispersed, the communication device generates a second symbol sequence by delaying the first symbol sequence, and the first symbol sequence and the second sequence number sequence are added to obtain a third symbol sequence, the fluctuation of the third symbol sequence obtained after the first symbol sequence is processed by adopting the mode is slow, correspondingly, the frequency spectrum of the third symbol sequence is concentrated, the bandwidth of the third symbol sequence is smaller than the bandwidth of the first symbol sequence, that is, the communication device provided by the embodiment of the present invention can effectively reduce the bandwidth of the first symbol sequence by processing the first symbol sequence.
Illustratively, the symbol rate of the third symbol sequence is 25Gbps, and fig. 9 shows a frequency spectrum diagram of the third symbol sequence. In fig. 9, the horizontal axis represents the frequency f, and the vertical axis represents the logarithm of the amplitude. As can be seen from fig. 9, the main lobe bandwidth of the third symbol sequence is 12.5GHz, and the value of the main lobe bandwidth of the third symbol sequence is half of the value of the symbol rate of the third symbol sequence.
As can be seen from a comparison between fig. 2 and fig. 9, a main lobe bandwidth of a third symbol sequence sent by the communication device in the embodiment of the present invention is smaller than a main lobe bandwidth of a symbol sequence to be transmitted sent by the sender device in the prior art, and a side lobe bandwidth of the third symbol sequence sent by the communication device is also smaller than a side lobe bandwidth of the symbol sequence to be transmitted sent by the sender device in the prior art.
And S104, the communication equipment performs digital-to-analog conversion on the third symbol sequence to generate a first analog signal.
And S105, the communication equipment converts the first analog signal into an optical signal and transmits the optical signal through an optical fiber channel.
In the embodiment of the present invention, S104 and S105 are the same as the processing procedure of the symbol sequence to be transmitted by the sending end device in the prior art, and are not described in detail here.
In the embodiment of the invention, the communication equipment generates the third symbol sequence with smaller bandwidth by carrying out time delay superposition processing on the first symbol sequence to be transmitted, so that the transmission of the third symbol sequence can enable the communication system to adopt equipment supporting lower bandwidth, and the realization cost of the system is greatly reduced.
S106, the receiving end equipment receives the optical signal sent by the communication equipment through the optical fiber channel.
S107, the receiving end device performs photoelectric conversion on the optical signal to generate a second analog signal.
And S108, the receiving end equipment performs analog-to-digital conversion on the second analog signal to generate a fourth symbol sequence.
The process of performing analog-to-digital conversion on the second analog signal by the receiving end device may be regarded as that the receiving end device samples the second analog signal by using a preset sampling frequency.
S106 to S108 in the embodiment of the present invention are the same as the processes of performing photoelectric conversion and analog-to-digital conversion on a received optical signal by receiving end equipment in the prior art, and are not described in detail here.
And S109, delaying the fourth symbol sequence by K second symbol periods by the receiving end equipment to generate a sixth symbol sequence.
And K is more than or equal to 1, the second symbol period is the symbol period of the fourth symbol sequence, and the symbol period of the fourth symbol sequence is related to the preset sampling frequency.
Preferably, in the embodiment of the present invention, the predetermined sampling frequency is the same as the frequency of the fourth symbol sequence.
And S110, the receiving end equipment adds the fourth symbol sequence and the sixth symbol sequence to obtain a seventh symbol sequence.
And S111, the receiving end equipment performs equalization processing on the seventh symbol sequence to obtain the seventh symbol sequence.
Corresponding to the processing of the first symbol sequence to be transmitted by the communication equipment, the receiving end equipment performs delay superposition processing on the fourth symbol sequence, and then the first symbol sequence to be transmitted sent by the communication equipment can be recovered.
To describe the signal processing method provided by the present invention in more detail, fig. 10 shows a flow of sending an optical signal by a communication device and receiving an optical signal by a receiving end device in an embodiment of the present invention.
{ b1, b2,. bn,. b2n } is a bit sequence to be transmitted, { I1, I2,. In } is a first symbol sequence to be transmitted, is a third symbol sequence, d (t) is a first analog signal, r (t) is a second analog signal, { v '1, v' 2,. v 'n } is a fourth symbol sequence, { v1, v2,. vn } is a sixth symbol sequence, { I' 1, I '2,. I' n } is a seventh symbol sequence, and Z-1 represents delaying the symbol sequence by one symbol period.
The signal processing flow shown in fig. 10 can refer to the above description of S101-S111, and is not described in detail here.
After the communication device obtains the first symbol sequence to be transmitted, the communication device encodes the first symbol sequence by using the precoder to generate a third symbol sequence with a bandwidth smaller than that of the first symbol sequence, and the bandwidth of the signal sent by the communication device is reduced by reducing the bandwidth of the third symbol sequence, so that the bandwidth of the signal sent by the communication device is reduced, the cost of the communication device is reduced, and the influence of chromatic dispersion on the signal sent by the communication device is reduced.
After an optical signal is transmitted in an optical fiber for a certain distance, the optical signal undergoes amplitude reduction and width broadening changes, which is called dispersion.
In the optical fiber, signal components with different wavelengths in the optical signal correspond to different transmission speeds, and therefore, the time taken for the signal components in the optical signal to reach the output end of the optical fiber is different, which may cause broadening of the optical signal, i.e., the optical pulse signal may cause a bandwidth increase after being transmitted for a distance along the optical fiber.
in general, after an optical signal is transmitted in an optical fiber for a certain distance, the optical signal is affected by chromatic dispersion, so that the bandwidth of the optical signal received by receiving end equipment is too large, and the sensitivity of the receiving end equipment for receiving the signal is reduced.
in the embodiment of the invention, because the bandwidth of the optical signal sent by the sending end equipment is smaller, the optical signal is less influenced by chromatic dispersion, so that the bandwidth of the optical signal received by the receiving end equipment is smaller, and the sensitivity of the receiving end equipment for receiving the signal is improved.
It will be clear to those skilled in the art that, for convenience and simplicity of description, the foregoing division of the functional modules is merely used as an example, and in practical applications, the above function distribution may be performed by different functional modules as needed, that is, the internal structure of the mobile device is divided into different functional modules to perform all or part of the above described functions. For the specific working processes of the system, the mobile device and the unit described above, reference may be made to the corresponding processes in the foregoing method embodiments, and details are not described here again.
In the several embodiments provided in the present application, it should be understood that the disclosed system, mobile device and method may be implemented in other ways. For example, the above-described mobile device embodiments are merely illustrative, and for example, the division of the modules or units is only one logical division, and other divisions may be realized in practice, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of the mobile devices or units through some interfaces, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
in addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, a network device, or the like) or a processor (processor) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. a precoder is characterized by comprising a delay unit and a processing unit connected with the delay unit; wherein the content of the first and second substances,
The delay unit is configured to receive a first symbol sequence, delay the first symbol sequence by N first symbol periods to generate a second symbol sequence, and send the second symbol sequence to the processing unit, where the number of levels of the first symbol sequence is M, the first symbol period is a time length between any two adjacent symbols in the first symbol sequence, N is greater than or equal to 1, and M is greater than or equal to 2;
the processing unit is configured to receive the first symbol sequence and the second symbol sequence sent by the delay unit, generate a third symbol sequence according to the first symbol sequence and the second symbol sequence, and send the third symbol sequence, where a bandwidth of the third symbol sequence is smaller than a bandwidth of the first symbol sequence.
2. The precoder of claim 1, wherein the processing unit comprises an adder subunit and a transmission subunit, the adder subunit being coupled to the delay unit and the adder subunit being coupled to the transmission subunit; wherein the content of the first and second substances,
The adding subunit is configured to receive the first symbol sequence and the second symbol sequence sent by the delay unit, and add the first symbol sequence and the second symbol sequence to obtain a third symbol sequence;
And the transmitting subunit is configured to transmit the third symbol sequence obtained by the adding subunit.
3. A communication device comprising a signal generator, a symbol modulator connected to the signal generator, and a digital-to-analog converter, wherein the communication device further comprises a precoder according to claim 1, the precoder being connected to both the symbol modulator and the digital-to-analog converter; wherein the content of the first and second substances,
The signal generator is used for generating a bit sequence to be transmitted and sending the bit sequence to be transmitted to the symbol modulator;
The symbol modulator is used for receiving the bit sequence to be transmitted sent by the signal generator, modulating the bit sequence to be transmitted by adopting a preset pulse amplitude modulation mode to generate a first symbol sequence, and sending the first symbol sequence to the precoder, wherein the level number of the first symbol sequence is M, and M is more than or equal to 2;
The precoder is configured to receive the first symbol sequence sent by the symbol modulator, encode the first symbol sequence to generate a third symbol sequence, and send the third symbol sequence to the digital-to-analog converter, where a bandwidth of the third symbol sequence is smaller than a bandwidth of the first symbol sequence;
The digital-to-analog converter is configured to receive the third symbol sequence sent by the precoder, perform digital-to-analog conversion on the third symbol sequence, generate a first analog signal, and send the first analog signal.
4. the communication device of claim 3, further comprising an optical modulator coupled to the digital-to-analog converter;
the optical modulator is configured to receive a first analog signal sent by the digital-to-analog converter, convert the first analog signal into an optical signal, and send the optical signal through an optical fiber channel.
5. a signal processing method applied to the communication apparatus according to claim 3 or 4, the signal processing method comprising:
The communication equipment acquires a first symbol sequence to be transmitted, wherein the level number of the first symbol sequence is M, and M is more than or equal to 2;
The communication equipment delays the first symbol sequence to be transmitted by N first symbol periods to generate a second symbol sequence, wherein the first symbol period is the time length between any two adjacent symbols in the first symbol sequence, and N is more than or equal to 1;
the communication equipment generates a third symbol sequence according to the first symbol sequence to be transmitted and the second symbol sequence, wherein the bandwidth of the third symbol sequence is smaller than that of the first symbol sequence to be transmitted;
And the communication equipment performs digital-to-analog conversion on the third symbol sequence to generate a first analog signal and transmits the first analog signal.
6. the signal processing method according to claim 5, wherein the determining, by the communication device, a third symbol sequence according to the first symbol sequence to be transmitted and the second symbol sequence, specifically comprises:
And the communication equipment adds the first symbol sequence to be transmitted and the second symbol sequence to obtain the third symbol sequence.
7. The signal processing method according to claim 5 or 6, wherein the obtaining, by the communication device, the first symbol sequence to be transmitted specifically includes:
The communication equipment generates a bit sequence to be transmitted;
And the communication equipment modulates the bit sequence to be transmitted by adopting a preset pulse amplitude modulation mode to obtain the first symbol sequence to be transmitted.
8. the signal processing method of claim 7, wherein the communicating transmits the first analog signal comprises:
The communication device converts the first analog signal to an optical signal and transmits the optical signal via a fiber channel.
9. A signal processing system, comprising the communication device according to any one of claims 3 to 4, and a receiving end device corresponding to the communication device, wherein the communication device is a transmitting end device, and the communication device and the receiving end device are connected by an optical fiber; wherein the content of the first and second substances,
the receiving end device is configured to receive an optical signal sent by the communication device, perform photoelectric conversion on the optical signal to generate a second analog signal, perform analog-to-digital conversion on the second analog signal to generate a fourth symbol sequence, and perform decoding processing and equalization processing on the fourth symbol sequence to generate a fifth symbol sequence.
10. The signal processing system of claim 9,
the receiving end device is specifically configured to delay the fourth symbol sequence by K second symbol periods to generate a sixth symbol sequence, add the fourth symbol sequence and the sixth symbol sequence to obtain a seventh symbol sequence, and perform equalization processing on the seventh symbol sequence to obtain the fifth symbol sequence, where K is greater than or equal to 1.
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| CN1508989A (en) * | 2002-12-18 | 2004-06-30 | 安捷伦科技有限公司 | Method and system for generating low-shaking non-return-to-zero optical data using photo-pulse stretcher |
| CN1863037A (en) * | 2005-12-08 | 2006-11-15 | 华为技术有限公司 | Clock acquiring system and method for optical communication system |
| CN101604978A (en) * | 2008-06-09 | 2009-12-16 | Atmel德国有限公司 | Be used to send the transtation mission circuit and the method for bit string waiting for transmission |
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| CN1508989A (en) * | 2002-12-18 | 2004-06-30 | 安捷伦科技有限公司 | Method and system for generating low-shaking non-return-to-zero optical data using photo-pulse stretcher |
| CN1863037A (en) * | 2005-12-08 | 2006-11-15 | 华为技术有限公司 | Clock acquiring system and method for optical communication system |
| CN101604978A (en) * | 2008-06-09 | 2009-12-16 | Atmel德国有限公司 | Be used to send the transtation mission circuit and the method for bit string waiting for transmission |
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