System, device, method, apparatus and medium for joint reception

Abstract

Example embodiments of the present disclosure relate to a communication system, a communication device, a communication method, an apparatus, and a computer medium for joint reception. In certain example embodiments, in the communication method, multiple signals are sent from multiple transmitters to multiple receivers through multiple wavelength division multiplexing channels. Moreover, the multiple signals received by the multiple receivers are provided to an equalizer coupled to the multiple receivers, and the multiple signals received by the multiple receivers are jointly equalized by the equalizer. This joint reception does not simply ignore the interference between the channels, but uses it as useful information, significantly improving the reception performance gain.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to communication technology, and more particularly, to a communication system, a communication device, a communication method, an apparatus, and a computer medium for joint reception. Background Art

[0002] The ITU-T is currently trying to start a new work item for 25G WDM-PON to match the project in the China Communications Standards Association (CCSA). It is also expected that the G.metro solution will be enhanced to support 25G line rates from the previous 10G line rate.

[0003] In addition, the research on wavelength division multiplexing (WDM) 25G / 50G technology and solutions is also to support the fourth generation (4G) / fifth generation (5G) base stations. At present, the supply chain of 25G-level electrical / optical components has matured, and 25G-level data center interconnection (DCI) has been achieved. Therefore, there is a need to standardize 25G / 50G WDM-PON for 5G fronthaul. Summary of the invention

[0004] In general, example embodiments of the present disclosure propose a communication system, a communication device, a communication method, an apparatus, and a computer medium for joint reception.

[0005] In a first aspect, an exemplary embodiment of the present disclosure provides a communication system. The communication system includes a plurality of transmitters, a plurality of receivers, and an equalizer coupled to the plurality of receivers. The plurality of transmitters are configured to transmit a plurality of signals to the plurality of receivers via a plurality of wavelength division multiplexing channels. The plurality of receivers are configured to provide the received plurality of signals to the equalizer. The equalizer is configured to perform joint equalization on the plurality of signals received by the plurality of receivers.

[0006] In a second aspect, an exemplary embodiment of the present disclosure provides a communication device. The communication device includes at least one processor and at least one memory storing computer program code. The at least one memory and the computer program code are configured to, together with the at least one processor, cause the communication device to cause multiple transmitters to send multiple signals to multiple receivers through multiple wavelength division multiplexing channels. The communication device also causes the multiple signals received by the multiple receivers to be provided to an equalizer coupled to the multiple receivers, and causes the multiple signals received by the multiple receivers to be jointly equalized by the equalizer.

[0007] In a third aspect, an exemplary embodiment of the present disclosure provides a communication method. In the communication method, multiple signals are sent from multiple transmitters to multiple receivers through multiple wavelength division multiplexing channels. Moreover, the multiple signals received by the multiple receivers are provided to an equalizer coupled to the multiple receivers, and the multiple signals received by the multiple receivers are jointly equalized by the equalizer.

[0008] In a fourth aspect, an exemplary embodiment of the present disclosure provides a device, comprising a component for executing the method according to the third aspect.

[0009] In a fifth aspect, an exemplary embodiment of the present disclosure provides a computer-readable storage medium having a computer program stored thereon. The computer program includes instructions, which, when executed by a processor on a device, cause the device to perform the operations performed by the communication device according to the second aspect.

[0010] It should be understood that the contents described in the summary of the invention are not intended to limit the key or important features of the exemplary embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The above and other features, advantages and aspects of the exemplary embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements, wherein:

[0012] Figure 1 An example wavelength plan for a WDM-PON is shown;

[0013] Figure 2 An example implementation of a conventional independent / incoherent reception scheme for WDM-PON or WDM P2P for 4G / 5G fronthaul is shown;

[0014] Figure 3(a) shows the ICI introduced due to AWG leakage;

[0015] FIG3( b ) shows a graph of BER versus transmit power for 4 channels;

[0016] Figure 4 An example communication system is shown in which example embodiments of the present disclosure may be implemented;

[0017] Figure 5 An example application scenario of an example embodiment of the present disclosure is shown;

[0018] Figure 6 A flowchart showing a joint reception method according to some example embodiments of the present disclosure is shown;

[0019] Figure 7 An example application scenario for implementing the above-mentioned multiple-input multiple-output (MIMO) equalization scheme according to certain embodiments of the present disclosure is shown;

[0020] Figure 8 A flowchart showing a joint reception method according to some other example embodiments of the present disclosure is shown;

[0021] Fig. 9 A diagram showing a comparison of reception performance between a joint reception method according to certain embodiments of the present disclosure and a conventional non-coherent direct detection (DD); and

[0022] Fig.10 A block diagram of a device suitable for implementing certain other example embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0023] The example embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain example embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the example embodiments set forth herein, which are instead provided for a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and example embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0024] The term "transmitter" as used herein refers to any suitable device having a transmitting function. The term "receiver" refers to any suitable device having a receiving function. The above-mentioned transmitting and receiving functions are not exclusive. For example, the transmitter may also have a receiving function, and the receiver may also have a transmitting function. In certain embodiments of the present disclosure, the receiver may feed back information to the transmitter via an uplink.

[0025] As used herein, the term "circuitry" refers to one or more of the following:

[0026] (a) hardware circuit implementation only (such as analog and / or digital circuit implementation only); and

[0027] (b) a combination of hardware circuitry and software, such as (where applicable): (i) a combination of analog and / or digital hardware circuitry and software / firmware, and (ii) any portion of a hardware processor and software (including a digital signal processor, software and memory that work together to enable an apparatus such as an OLT or other computing device to perform various functions); and

[0028] (c) A hardware circuit and / or processor, such as a microprocessor or portion of a microprocessor, that requires software (eg, firmware) for operation but can operate without software when no software is needed for operation.

[0029] The definition of circuitry applies to all uses of this term in this application, including in any claims. As another example, the term "circuitry" as used herein also covers an implementation of a hardware circuit or processor (or multiple processors), or a portion of a hardware circuit or processor, or accompanying software or firmware. For example, the term "circuitry" also covers a baseband integrated circuit or a processor integrated circuit or a similar integrated circuit in an OLT or other computing device, if applicable to a particular claim element.

[0030] The term "including" and its variations used herein are open inclusions, i.e., "including but not limited to". The term "based on" means "based at least in part on". The term "an example embodiment" means "at least one example embodiment"; the term "another example embodiment" means "at least one additional example embodiment". The relevant definitions of other terms will be given in the following description.

[0031] As used herein, the terms "first," "second," and the like may be used herein to describe various elements, which should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the exemplary embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0032] Currently, the standardization work of high-speed (above 25G) WDM has begun. Figure 1 FIG. 4 shows an example wavelength plan of a WDM-PON, in which a 100 GHz dense wavelength division multiplexing (DWDM) wavelength spacing is used. Figure 1 As shown, downlink wavelengths 105 and 110 are spaced apart from uplink wavelengths 115 and 120 .

[0033] Whether using point-to-point (P2P) or point-to-multipoint (P2MP) topology, high-speed WDM is susceptible to two major channel impairments, namely inter-symbol-interference (ISI) and inter-channel-interference (ICI).

[0034] ISI is attributed to two main factors, namely, chromatic dispersion (CD) and bandwidth limitation of the end-to-end (E2E) link response. ISI has been widely studied in single-channel communications. Since the underlying digital signal processing (DSP) algorithm can use the dual binary format as an intermediate stage for the final symbol inference, ISI is actually a nonlinear (NL) problem for Pulse Amplitude Modulation 4-level (PAM4) modulation and even for non-return to zero (NRZ) coding. That is, ISI is actually NL-ISI.

[0035] ICI only occurs in WDM systems and is attributed in the perpendicular dimension to ISI to the following aspects, namely cross phase modulation (XPM) caused by the Kerr effect, four wave mixing (FWM) between channels, and arrayed waveguide gratings (AWG) leakage from other channels.

[0036] A traditional WDM-PON solution for cellular fronthaul is to manage only the ISI on each channel, or NL-ISI, while ignoring the ICI between channels. This solution has low complexity and can achieve acceptable performance for low line rates.

[0037] Figure 2 An example implementation of a traditional independent / non-coherent reception scheme for WDM-PON or WDM P2P for 4G / 5G fronthaul is shown.

[0038] like Figure 2As shown, at the transmitting side 210, four or more channels are wavelength-division multiplexed and then transmitted through a common optical fiber 215. Correspondingly, at the receiving side 220, four independent receivers 222, 224, 226 and 228 detect each channel.

[0039] exist Figure 2 In the scheme shown, a small signal model (SSM) can be used to approximate low-order modulation formats, such as on-off keying (OOK), so that nonlinear FWM and AWG crosstalk can be largely avoided. Moreover, this scheme has low complexity and can achieve 4×10Gb / s applications on 10G-level optical devices (such as in G.Metro). As long as the line rate remains at 10G bits / second (b / s), the performance is acceptable. However, ICI will be very serious when the line rate is as high as 25G baud rate. If ICI is simply ignored, the reception performance will be degraded.

[0040] Figure 3(a) and 3(b) Shows the use of Figure 2 The performance of the direct detection (DD) scheme is shown in FIG3(a), where FIG3(b) shows the ICI introduced due to AWG leakage, and FIG3(b) shows a graph of the 4-channel bit error rate (BER) versus the transmit power.

[0041] In the example shown in FIG3(a), channel 301 (denoted as Ch1), channel 302 (denoted as Ch2), channel 303 (denoted as Ch3) and channel 304 (denoted as Ch4) are wavelength division multiplexed. As shown in FIG3(a), the frequencies of channel 301, channel 302, channel 303 and channel 304 gradually increase on the spectrum. Interference from channel 301 and channel 303 exists on channel 302.

[0042] In the example shown in FIG3(a), the line rate is 25G baud rate and PAM4 modulation is used. As shown in FIG3(b), in this case, the BER curves 311, 312, 313, and 314 of the four channels 301, 302, 303, and 304 are all U-shaped. As the transmit power increases, the BER deteriorates due to the increase in ICI. The BER valleys of the inner channels 302 and 303 hover above 1E-2, while the outer channels 301 and 304 are above 3.8E-3.

[0043] The inventors note that this traditional solution is difficult to expand to support 4×25G / 50G rates for 5G because it cannot prevent crosstalk. However, in order to support 5G fronthaul, key performance indicators (KPIs) are set for multiple objects at the same time, including line rate (for example, from traditional 10G to 25G / 50G), modulation format (for example, from OOK to PAM4), tolerance to NL, etc. Therefore, 25G / 50G-WDM for 5G needs to solve the complex NL-ISI-ICI problem, which has not been involved in previous WDM-PON research.

[0044] To this end, the example embodiments of the present disclosure propose a joint reception scheme to solve the interference problem (e.g., ICI problem) in the WDM transmission process, thereby reducing the WDM transmission error rate. In the joint WDM reception scheme, multiple receivers are coupled to the same equalizer, and the equalizer performs joint equalization on the signals received by the multiple receivers. This joint signal equalization can eliminate ICI between different channels. In some embodiments, the joint WDM reception scheme can also eliminate interference (e.g., ICI) and crosstalk (e.g., ISI) at the same time. Compared with the traditional independent / incoherent reception scheme, the joint reception scheme according to the example embodiments of the present disclosure does not simply ignore the interference between channels, but uses it as useful information, so that a significant improvement in the reception performance gain can be achieved.

[0045] Figure 4 4 shows an example communication system 400 in which example embodiments of the present disclosure may be implemented. Figure 4 As shown, the communication system 400 includes a plurality of transmitters 405-1, ..., 405-N and a plurality of receivers 410-1, ..., 410-N, where N is any appropriate positive integer greater than 1. For convenience of discussion, the plurality of transmitters 405-1, ..., 405-N are also individually or collectively referred to as transmitters 405, and the plurality of receivers 410-1, ..., 410-N are also individually or collectively referred to as receivers 410.

[0046] Multiple transmitters 405-1, ..., 405-N send multiple signals to multiple receivers 410-1, ..., 410-N via optical fiber 425 in a wavelength division multiplexing manner. Channel 425 can be physically carried by optical fiber. Each transmitter 405 sends a signal to a corresponding receiver 410 through a corresponding channel, and the channels used by different transmitter-receiver pairs are wavelength division multiplexed. Figure 5 Let's discuss a specific example.

[0047] Figure 5 An example application scenario 500 of the communication system 400 is shown.

[0048] like Figure 5 As shown, in scenario 500, four transmitters 405-1, 405-2, 405-3 and 405-4 transmit signals to four receivers 410-1, 410-2, 410-3 and 410-4 via four wavelength division multiplexed channels 501, 502, 503 and 504, that is, N = 4. The four wavelength division multiplexed channels 501, 502, 503 and 504 are physically carried by the optical fiber 425. However, due to the influence of, for example, XPM caused by the Kerr effect, FWM between channels and / or AWG leakage from other channels, ICI is generated between the four channels 501, 502, 503 and 504.

[0049] In various embodiments of the present disclosure, Figure 4 As shown, the communication system 400 further includes an equalizer 430 coupled to the plurality of receivers 410-1, ..., 410-N, for performing joint equalization on the signals received by the plurality of receivers 410-1, ..., 410-N. Through joint equalization, the influence of interference between the channels can be eliminated, thereby improving performance gain and reducing bit error rate.

[0050] Figure 6 A flowchart of a joint reception method 600 according to some exemplary embodiments of the present disclosure is shown. The method 600 can be Figure 4 For the convenience of discussion, the following will be combined with Figure 4 Method 600 is described.

[0051] In block 605, multiple signals are sent from multiple transmitters 405-1, ..., 405-N to multiple receivers 410-1, ..., 410-N through multiple wavelength division multiplexing channels. Wavelength division multiplexing can be implemented in any appropriate manner and using any appropriate device. As an example, the AGW can act as a wavelength division multiplexer and a wavelength division multiplexer to wavelength division multiplex the multiple signals sent from the multiple transmitters 405-1, ..., 405-N, and to wavelength division multiplex the signals received from the optical fiber 425 to obtain signals transmitted on each channel.

[0052] In block 610, the multiple signals received by the multiple receivers 410-1, ..., 410-N are provided to the equalizer 430 coupled to the receivers 410-1, ..., 410-N. In some embodiments, in order to solve the crosstalk (e.g., ISI) problem, the received signal can be serial-to-parallel converted at each receiver 410 to obtain multiple parallel signals, and the parallel signals are provided to the equalizer 430. In this way, the equalizer 430 can not only utilize the characteristics of the transmission signals on different channels when performing joint signal equalization, but also utilize the characteristics of adjacent signals on the same channel, thereby improving the equalization efficiency, which will be described in detail later.

[0053] At block 615, the signals received by the plurality of receivers 410-1, ..., 410-N are jointly equalized by the equalizer 430. For example, for a signal received by a certain receiver (e.g., the receiver 410-1), characteristics of signals received at one or more other receivers may be utilized for equalization, thereby eliminating interference between different channels.

[0054] In an embodiment where each receiver 410-1, ..., 410-N inputs multiple parallel signals to the equalizer 430, the equalizer 430 can perform joint equalization on the multiple parallel signals from these receivers, and on the output side, the equalizer 430 can output multiple signals, each corresponding to a channel. In this way, the joint equalization performed by the equalizer 430 can simultaneously consider the effects of both ICI and ISI, and can simultaneously eliminate interference (e.g., ICI) between transmission signals on different channels and interference (e.g., ISI) between adjacent signals on the same channel, thereby effectively reducing the transmission error rate and greatly improving the receiving performance gain.

[0055] Figure 7 An example application scenario 700 for implementing the above-mentioned multiple-input multiple-output (MIMO) equalization scheme according to some embodiments of the present disclosure is shown. In this example, four transmitters 405-1, 405-2, 405-3 and 405-4 transmit data to four receivers 410-1, 410-2, 410-3 and 410-4 via an optical fiber 425 in a wavelength division multiplexing manner. That is, N=4.

[0056] Scenario 700 is cellular fronthaul. Transmitters 405-1, 405-2, 405-3 and 405-4 are located at the tail end 702, receiving low-speed data (such as 1G and / or 10G data) from the radio unit (Radio Unit, referred to as RU) 704, and combining the received low-speed data (such as 1G and / or 10G data) into a 25 / 50G data rate and sending it out through wavelength division multiplexing. Receivers 410-1, 410-2, 410-3 and 410-4 and equalizer 730 are located at the head end 706, and are used to provide the received 25 / 50G high-speed data to the distributed unit (Distributed Unit, referred to as DU) 708.

[0057] It should be understood that the cellular fronthaul scenario is merely an example and not a limitation. The joint reception method according to the embodiments of the present disclosure can be applied to any WDM transmission scenario, and the scope of the present disclosure is not limited in this respect.

[0058] like Figure 7 As shown, each transmitter 405-1, 405-2, 405-3 or 405-4 includes a 25 / 50G demarcator 710-1, 710-2, 710-3 or 710-4 for converting 1 / 10G low-rate data into 25 / 50G high-rate data, and includes an electro-optical converter (E / O) 715-1, 715-2, 715-3 or 715-4 for converting electrical signals into optical signals.

[0059] The obtained optical signal is transmitted to AGW 720 for wavelength division multiplexing and then transmitted to AGW 725 through optical fiber 425 for wavelength division multiplexing. It should be understood that Figure 7 The wavelength division multiplexing and wavelength demultiplexing implemented by AGW 720 and 725 are shown as examples only, not limitations. Wavelength division multiplexing and wavelength demultiplexing can be implemented in any appropriate manner and using any appropriate devices.

[0060] The four signals obtained by wavelength division multiplexing are input to four receivers 410-1, 410-2, 410-3 and 410-4 respectively. In this example, each receiver 410-1, 410-2, 410-3 or 410-4 includes an optical-to-electrical converter (O / E) 730-1, 730-2, 730-3 or 730-4 for converting the received optical signal into an electrical signal, and includes an analog-to-digital converter (A / D) 735-1, 735-2, 735-3 or 735-4 for converting the analog signal into a digital signal. Each receiver 410-1, 410-2, 410-3 or 410-4 also includes a serial-to-parallel converter 740-1, 740-2, 740-3 or 740-4 for converting the serial signal into a parallel signal.

[0061] The parallel signals output by each receiver 410-1, 410-2, 410-3 or 410-4 are input to the equalizer 430. In this example, the equalizer 430 includes a convergence module 745, which converges the parallel signals from the receivers 410-1, 410-2, 410-3 and 410-4, and then provides them to the nK:n equalization module 750 in the equalizer 430 for joint equalization processing according to a predetermined rule, so as to eliminate ICI and ISI.

[0062] nK represents the number of input channels of the equalization module 750, and n represents the number of output channels of the equalization module 750. As an example, n can be the number of wavelength division multiplexing channels, for example, n is 4 in this example. K can be the longitudinal channel memory length, for example, an integer of about 10. In this way, the input of the nK:n equalization module 750 is nK parallel signals from each receiver 410-1, 410-2, 410-3 and 410-4, wherein K parallel signals are obtained from each receiver 410-1, 410-2, 410-3 or 410-4. Accordingly, the convergence module 735 can provide the signals from the receivers 410-1, 410-2, 410-3 and 410-4 to the nK:n equalization module 750 according to this rule. The output of the nK:n equalization module 750 is n parallel symbols, each corresponding to a channel. In this way, crosstalk / interference can be used as useful information instead of simply ignoring it, thereby improving reception performance.

[0063] In some embodiments, the equalizer 430 may implement joint signal equalization based on a neural network (NN), also known as NN equalization (NN-EQ). NN-EQ can effectively solve the nonlinear crosstalk / interference problem.

[0064] In these embodiments, the equalizer 430 may be pre-trained using a training signal. For example, a training signal may be sent from a plurality of transmitters 405-1, ..., 405-N to a plurality of receivers 410-1, ..., 410-N via a plurality of wavelength division multiplexing channels. The training signal may be any appropriate signal known in advance. As an example, the transmitters 405-1, ..., 405-N may send a known preamble to the corresponding receivers 410-1, ..., 410-N. Then, the equalizer 430 is trained using the training signal received by the receivers 410-1, ..., 410-N as the input of the equalizer 430 and the training signal sent by the transmitters 405-1, ..., 405-N as the output of the equalizer 430.

[0065] The above training process can be carried out to match the application use case of the equalizer 430. For example, in an embodiment in which each receiver 410-1, ..., 410-N provides multiple parallel signals to the equalizer 430 so as to eliminate ICI and ISI simultaneously through joint equalization, during the training process, after receiving the training signals from the transmitters 405-1, ..., 405-N, the receivers 410-1, ..., 410-N can perform serial-to-parallel conversion and provide the multiple parallel signals obtained therefrom to the equalizer 430 as input. The equalizer 430 uses these parallel signals as input and uses the training signals sent by the transmitters 405-1, ..., 405-N as output to carry out the training process. In this way, during the training phase, the equalizer 430 can not only learn the ICI between the channels, but also learn the ISI within each channel. After training, the equalizer 430 can process the ISI and ICI of all wavelength division multiplexing channels in parallel.

[0066] Since it is necessary to perform coherent processing on signals from multiple parallel channels, in order to further improve the receiving performance, in some embodiments, time synchronization processing can also be performed on the receiver side and the transmitter side. In the context of the present disclosure, time synchronization is also called alignment.

[0067] As an example, in the time synchronization (or alignment) process of the receivers, a signal may be sent from a certain transmitter (e.g., transmitter 405-1) to multiple receivers 410-1, ..., 410-N. Then, a reference time for synchronization is determined based on the reception time delay of each receiver 410-1, ..., 410-N receiving the signal, and the receivers 410-1, ..., 410-N are time synchronized based on the reference time.

[0068] The reference time may be determined in any appropriate manner. For example, the longest path between the transmitter and the receiver may be used as a reference, and the latest reception time may be found from multiple reception times as the reference time. Accordingly, a buffer may be set for each channel or the sampling time of each receiver may be delayed with reference to the reference time, thereby aligning the reception times of the various receivers 410. In this way, the transmission distance mismatch between the receivers 410-1, ..., 410-N may be eliminated.

[0069] In the time synchronization process of the transmitter, multiple signals can be sent from multiple transmitters 405-1, ..., 405-N to a receiver (e.g., receiver 410-1) through a wavelength division multiplexing channel (e.g., sequentially or in turn). The reference delay for transmitter synchronization is determined based on the reception delay of the receiver receiving these signals. For example, the receiver can calculate the reception delay of the signal from each transmitter 405-1, ..., 405-N, and feed it back to each transmitter 405-1, ..., 405-N through an uplink channel. As an example, the transmitters 405-1, ..., 405-N can use the maximum delay as the reference delay and postpone their respective transmission times to align with the reference delay. Other ways and criteria for determining the reference delay are also feasible, and the scope of the present disclosure is not limited in this respect. In this way, the transmission distance mismatch between the transmitters 405-1, ..., 405-N can be eliminated.

[0070] It should be understood that the synchronization between receivers and the synchronization between transmitters can be performed in any appropriate order. For example, the synchronization between receivers can be performed first and then the synchronization between transmitters is just an example. As an alternative, the synchronization between transmitters can be performed first and then the synchronization between receivers. Moreover, the time synchronization between the receiver and the transmitter can be performed at any appropriate time. In some embodiments, it can be performed before training the equalizer to further improve the training effect. Figure 8 Let’s discuss a specific example.

[0071] Figure 8 A flowchart of a joint reception method 800 according to some other exemplary embodiments of the present disclosure is shown. In this example, four transmitters 405-1, 405-2, 405-3 and 405-4 transmit data to four receivers 410-1, 410-2, 410-3 and 410-4 through four wavelength division multiplexing channels. That is, N=4.

[0072] like Figure 8As shown, in block 805, receiver-side alignment is performed. For example, a signal, such as a preamble, is sent by a transmitter (e.g., transmitter 405-1). Due to the influence of factors such as crosstalk and / or AWG leakage, four receivers 410-1, 410-2, 410-3, and 410-4 will receive a signal with a certain delay (distortion). As an example, the receiving times of receivers 410-1, 410-2, 410-3, and 410-4 are represented as T1, T2, T3, and T4, respectively. The longest path can be found as a reference, that is, the reference time T0=max(T1, T2, T3, T4). Then, a buffer can be set for each channel, or the sampling time can be postponed by T0-Ti (i=1, 2, 3, 4), so as to align the receiving times of the four receivers 410-1, 410-2, 410-3, and 410-4.

[0073] In block 810, transmitter-side alignment is performed. Four transmitters 405-1, 405-2, 405-3, and 405-4 send different signals to a receiver (e.g., receiver 410-1). As an example, the four transmitters may send sequentially or in turns. After one transmitter finishes sending, another transmitter starts sending. Accordingly, the receiver may calculate the receiving delay of the signal received from each transmitter 405-1, 405-2, 405-3, or 405-4 in turn, for example, represented as D1, D2, D3, and D4, respectively. The receiver may feed back to each transmitter 405-1, 405-2, 405-3, and 405-4 via an uplink. Each transmitter 405-1, 405-2, 405-3, and 405-4 determines the maximum delay D0=max(D1, D2, D3, D4) therein as the reference delay, and postpones the respective transmission time to D0. In this way, the transmission times of the four transmitters 405-1, 405-2, 405-3 and 405-4 can be aligned.

[0074] In block 815, the equalizer 435 is trained. For example, four different preamble codes may be sent from four transmitters 405-1, 405-2, 405-3 or 405-4 as training signals. Accordingly, for example, affected by NL-ISI-ICI, four receivers 410-1, 410-2, 410-3 and 410-4 receive four distorted training signals R1, R2, R3 and R4. Each training signal R1, R2, R3 and R4 includes a plurality of serial symbols. These serial symbols are converted into four groups of parallel symbols S2P(R1), S2P(R2), S2P(R3) and S2P(R4) by serial-to-parallel conversion, and the width of each group of parallel symbols is m, i.e., the channel memory length.

[0075] The four sets of parallel symbols S2P(R1), S2P(R2), S2P(R3) and S2P(R4) can be converged into Figure 7 The aggregation module 745 shown in FIG. 1 is then provided to Figure 7 The equalization module 750 shown in FIG. 7 is used as the MIMO input at time k. The MIMO output of the equalization module 750 is the estimated T1(k)', T2(k)', T3(k)' and T4(k)'.

[0076] As an example, the four receivers 410-1, 410-2, 410-3 and 410-4 receive preamble codes R1, R2, R3 and R4 as shown in the following formulas (1)-(4):

[0077] R1=R1(t0),R1(t1),R1(t2)…R1(tm) (1)

[0078] R2=R2(t0),R2(t1),R2(t2)…R2(tm) (2)

[0079] R3=R3(t0),R3(t1),R3(t2)…R3(tm) (3)

[0080] R4=R4(t0),R4(t1),R4(t2)…R4(tm) (4)

[0081] The four sets of parallel symbols S2P(R1), S2P(R2), S2P(R3) and S2P(R4) obtained by serial-to-parallel conversion are shown in the following formulas (5)-(8):

[0082]

[0083]

[0084]

[0085]

[0086]

[0087] At time t=k, the MIMO input to the equalization module 750 is:

[0088]

[0089] At time t=k, the MIMO output of the equalization module 750 is:

[0090]

[0091] As shown above, in this example, at time t=t0, the convergence module 740 inputs the following symbols to the joint equalization module 745:

[0092]

[0093] At time t=t1, the convergence module 740 inputs the following symbols to the joint equalization module 745:

[0094]

[0095] And so on.

[0096] At the same time, the transmission symbol at each time t is provided as an output to the equalization module 745. Thus, the training of the equalization module 745 is achieved.

[0097] In block 820, data transmission and joint equalization are performed using the trained equalizer 430. Thus, ISI-ICI problems, including linear and nonlinear ISI-ICI problems, can be solved. Compared with traditional independent / incoherent reception schemes, this joint processing approach brings about a significant reduction in BER.

[0098] Fig. 9 A comparison chart of reception performance between a joint reception method according to certain embodiments of the present disclosure and a traditional non-coherent direct detection (DD) is shown.

[0099] In this example, 4 10GHz bandwidth optical devices are used as transmitters, and 100GHz gap WDM is used for 50Gb / s PAM4 transmission over 20km single mode fiber. AWG is used to act as WDM and WDM, and WDM and WDM are performed at the transmitter and receiver ends. On the receiver side, the equalizer adopts NN structure, where {40, 10, 4} neurons are used for input layer, hidden layer and output layer respectively. Fig. 9 As shown, compared with the traditional incoherent direct detection, the use of joint NN (JNN) achieves a 10-fold BER reduction.

[0100] Fig.10 A block diagram of a device 1000 suitable for implementing certain example embodiments of the present disclosure is shown.

[0101] As shown, device 1000 includes processor 1010. Processor 1010 controls the operation and functionality of device 1000. For example, in some example embodiments, processor 1010 may perform various operations with the aid of instructions 1030 stored in memory 1020 coupled thereto. Memory 1020 may be of any suitable type suitable for the local technical environment and may be implemented using any suitable data storage technology, including but not limited to semiconductor-based memory devices, magnetic memory devices and systems, and optical memory devices and systems. Although Fig.10 Only one memory unit is shown in FIG. 1 , but there may be multiple physically different memory units in device 1000 .

[0102] The processor 1010 may be of any suitable type suitable for the local technical environment, and may include, but is not limited to, one or more of a general purpose computer, a special purpose computer, a microcontroller, a digital signal controller (DSP), and a controller-based multi-core controller architecture. The device 1000 may also include multiple processors 1010. The processor 1010 is coupled to the transceiver 1040. The transceiver 1040 may receive and send information by means of optical fibers, cables, and / or other components. The processor 1010 may execute instructions to enable the above reference Figures 6 to 8 The described methods 600 and 800 can be implemented.

[0103] Device 1000 can be independent of Figure 4 The transmitter 405, the receiver 410, and the equalizer 430 shown in the figure may be integrated in the transmitter 405, the receiver 410, or the equalizer 430. Alternatively, the device 1000 may be distributedly arranged on one or more of the transmitter 405, the receiver 410, or the equalizer 430, or may be partially arranged on one or more of the transmitter 405, the receiver 410, or the equalizer 430, and partially arranged on other separate devices. Figures 4 to 9 All the features described are applicable to device 1000 and will not be described in detail here.

[0104] In general, various example embodiments of the present disclosure may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Certain aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. When various aspects of the example embodiments of the present disclosure are illustrated or described as block diagrams, flow charts, or using some other graphical representation, it will be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general purpose hardware or controllers or other computing devices, or some combination thereof as non-limiting examples.

[0105] As an example, the example embodiments of the present disclosure can be described in the context of machine executable instructions, such as included in the program module executed in the device on the real or virtual processor of the target. Generally speaking, program modules include routines, programs, libraries, objects, classes, components, data structures, etc., which perform specific tasks or implement specific abstract data structures. In each example embodiment, the functions of the program modules can be merged or divided between the described program modules. The machine executable instructions for program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in both local and remote storage media.

[0106] The computer program code for realizing the method of the present disclosure can be written in one or more programming languages. These computer program codes can be provided to the processor of general-purpose computer, special-purpose computer or other programmable data processing device, so that the program code, when being executed by computer or other programmable data processing device, causes the function / operation specified in flow chart and / or block diagram to be implemented. The program code can be executed completely on computer, partly on computer, as independent software package, partly on computer and partly on remote computer or completely on remote computer or server.

[0107] In the context of the present disclosure, a machine-readable medium may be any tangible medium that contains or stores a program for or related to an instruction execution system, apparatus, or device. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. More detailed examples of machine-readable storage media include an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0108] In addition, although the operations are depicted in a particular order, this should not be understood as requiring such operations to be completed in the particular order shown or in a sequential order, or to perform all illustrated operations to obtain the desired results. In some cases, multitasking or parallel processing can be beneficial. Similarly, although the above discussion contains certain specific implementation details, this should not be interpreted as limiting the scope of any invention or claim, but should be interpreted as a description of a specific example embodiment that can be directed to a specific invention. Certain features described in the context of separate example embodiments in this specification may also be integrated and implemented in a single example embodiment. Conversely, the various features described in the context of a single example embodiment may also be implemented separately in multiple example embodiments or in any suitable sub-combination.

[0109] Although the subject matter has been described in language specific to structural features and / or methodological acts, it should be understood that the subject matter defined in the appended claims is not limited to the specific features or acts described above. Instead, the specific features and acts described above are disclosed as example forms of implementing the claims.

[0110] Various example embodiments of the present disclosure have been described. In addition or alternative to the above, the following examples are described. The functionality described in any of the following examples can be used with any other examples described herein.

[0111] In some aspects, a communication system includes: multiple transmitters configured to transmit multiple signals to multiple receivers via multiple wavelength division multiplexing channels; multiple receivers configured to provide the received multiple signals to an equalizer coupled to the multiple receivers; and an equalizer configured to jointly equalize the multiple signals received by the multiple receivers.

[0112] In some embodiments, the plurality of receivers are configured to provide the received plurality of signals to the equalizer by: at each of the plurality of receivers, performing serial-to-parallel conversion on the received signal to obtain a plurality of parallel signals; and providing the plurality of parallel signals to the equalizer.

[0113] In some embodiments, the equalizer is configured to perform joint equalization by jointly equalizing multiple parallel signals from multiple receivers.

[0114] In some embodiments, the plurality of transmitters are further configured to transmit a plurality of training signals to the plurality of receivers via a plurality of wavelength division multiplexing channels. The plurality of receivers are further configured to provide the received plurality of training signals to the equalizer as input. And the equalizer is further configured to perform a training process using the plurality of training signals received by the plurality of receivers as input and using the plurality of training signals transmitted by the plurality of transmitters as output.

[0115] In some embodiments, the plurality of transmitters are further configured to perform time synchronization between the plurality of transmitters. The plurality of receivers are further configured to perform time synchronization between the plurality of receivers.

[0116] In some embodiments, the multiple transmitters are also configured to: send multiple signals from each of the multiple transmitters to one of the multiple receivers through a wavelength division multiplexing channel; determine a reference delay for time synchronization between the transmitters based on multiple reception delays of the multiple receivers receiving the multiple signals from the multiple transmitters; and perform time synchronization between the multiple transmitters based on the reference delay.

[0117] In some embodiments, the multiple receivers are also configured to: receive a signal from one of the multiple transmitters; determine a reference time for time synchronization between the receivers based on multiple reception time delays of the signals received by the multiple receivers; and perform time synchronization between the multiple receivers based on the reference time.

[0118] In some aspects, a communication device includes: at least one processor; and at least one memory storing computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the communication device to: cause multiple transmitters to send multiple signals to multiple receivers through multiple wavelength division multiplexing channels; cause the multiple signals received by the multiple receivers to be provided to an equalizer coupled to the multiple receivers; and cause the multiple signals received by the multiple receivers to be jointly equalized by the equalizer.

[0119] In some embodiments, the communication device is caused to cause multiple signals received by multiple receivers to be provided to an equalizer by causing, at each of the multiple receivers, serial-to-parallel conversion of the received signal to obtain multiple parallel signals, and providing the multiple parallel signals to the equalizer.

[0120] In certain embodiments, the communication device is caused to cause joint equalization by causing joint equalization of a plurality of parallel signals from a plurality of receivers by an equalizer.

[0121] In some embodiments, the communication device is also caused to: cause multiple training signals to be sent from multiple transmitters to multiple receivers through multiple wavelength division multiplexing channels; and cause the multiple training signals received by the multiple receivers to be provided to an equalizer as input; and cause a training process to be performed by the equalizer using the multiple training signals received by the multiple receivers as input to the equalizer and using the multiple training signals sent by the multiple transmitters as outputs of the equalizer.

[0122] In certain embodiments, the communication device is further caused to: cause time synchronization between the plurality of receivers; and cause time synchronization between the plurality of transmitters.

[0123] In some embodiments, a communication device is caused to cause time synchronization between multiple receivers by: causing a signal to be sent from one of multiple transmitters to multiple receivers; causing a reference time for time synchronization of the multiple receivers to be determined based on multiple reception time delays of the signals received by the multiple receivers; and causing time synchronization between the multiple receivers to be performed based on the reference time.

[0124] In some embodiments, a communication device is caused to cause time synchronization between multiple transmitters by: causing multiple signals to be transmitted in turn from each of the multiple transmitters to one of the multiple receivers via a wavelength division multiplexing channel; causing a reference delay for time synchronization of the multiple transmitters to be determined based on multiple reception delays of the multiple receivers receiving the multiple signals from the multiple transmitters; and causing time synchronization between the multiple transmitters to be performed based on the reference delay.

[0125] In some aspects, a communication method includes: sending multiple signals from multiple transmitters to multiple receivers through multiple wavelength division multiplexing channels; providing the multiple signals received by the multiple receivers to an equalizer coupled to the multiple receivers; and jointly equalizing the multiple signals received by the multiple receivers through the equalizer.

[0126] In some embodiments, providing the plurality of signals received by the plurality of receivers to the equalizer includes: at each of the plurality of receivers, performing serial-to-parallel conversion on the received signal to obtain a plurality of parallel signals, and providing the plurality of parallel signals to the equalizer.

[0127] In some embodiments, performing the joint equalization includes: performing the joint equalization on a plurality of parallel signals from a plurality of receivers by an equalizer.

[0128] In some embodiments, the communication method also includes: sending multiple training signals from multiple transmitters to multiple receivers through multiple wavelength division multiplexing channels; providing the multiple training signals received by the multiple receivers to an equalizer as input; and performing a training process through the equalizer, using the multiple training signals received by the multiple receivers as input of the equalizer and using the multiple training signals sent by the multiple transmitters as output of the equalizer.

[0129] In some embodiments, the communication method further includes: performing time synchronization between multiple receivers; and performing time synchronization between multiple transmitters.

[0130] In some embodiments, time synchronization of multiple receivers includes: sending a signal from one of multiple transmitters to multiple receivers; determining a reference time for time synchronization of the multiple receivers based on multiple reception time delays of the signals received by the multiple receivers; and performing time synchronization between the multiple receivers based on the reference time.

[0131] In some embodiments, time synchronization of multiple transmitters includes: sending multiple signals from each of the multiple transmitters to one of the multiple receivers in turn through a wavelength division multiplexing channel; determining a reference delay for time synchronization of the multiple transmitters based on multiple reception delays of the multiple receivers in receiving the multiple signals from the multiple transmitters; and performing time synchronization between the multiple transmitters based on the reference delay.

[0132] In some aspects, an apparatus includes: a component for transmitting multiple signals from multiple transmitters to multiple receivers through multiple wavelength division multiplexing channels; a component for providing the multiple signals received by the multiple receivers to an equalizer coupled to the multiple receivers; and a component for jointly equalizing the multiple signals received by the multiple receivers through the equalizer.

[0133] In some embodiments, a component for providing multiple signals received by multiple receivers to an equalizer includes: a component for performing serial-to-parallel conversion on the received signal at each of the multiple receivers to obtain multiple parallel signals, and a component for providing the multiple parallel signals to the equalizer.

[0134] In some embodiments, means for performing joint equalization includes means for jointly equalizing a plurality of parallel signals from a plurality of receivers via an equalizer.

[0135] In some embodiments, the device also includes: a component for sending multiple training signals from multiple transmitters to multiple receivers through multiple wavelength division multiplexing channels; a component for providing the multiple training signals received by the multiple receivers to an equalizer as input; and a component for performing a training process through the equalizer using the multiple training signals received by the multiple receivers as input of the equalizer and using the multiple training signals sent by the multiple transmitters as output of the equalizer.

[0136] In some embodiments, the apparatus further comprises: means for performing time synchronization between the plurality of receivers; and means for performing time synchronization between the plurality of transmitters.

[0137] In some embodiments, a component for time synchronization of multiple receivers includes: sending a signal from a transmitter among multiple transmitters to multiple receivers; a component for determining a reference time for time synchronization of the multiple receivers based on multiple reception time delays of the signals received by the multiple receivers; and a component for time synchronization between the multiple receivers based on the reference time.

[0138] In some embodiments, a component for time synchronization of multiple transmitters includes: a component for sending multiple signals from each of the multiple transmitters to one of the multiple receivers through a wavelength division multiplexing channel; a component for determining a reference delay for time synchronization of the multiple transmitters based on multiple reception delays of the multiple receivers receiving the multiple signals from the multiple transmitters; and a component for time synchronization between the multiple transmitters based on the reference delay.

[0139] In some aspects, a computer-readable storage medium has program instructions stored thereon, which, when executed by a processor on a device, causes the device to: cause multiple transmitters to send multiple signals to multiple receivers through multiple wavelength division multiplexing channels; cause the multiple signals received by the multiple receivers to be provided to an equalizer coupled to the multiple receivers; and cause the multiple signals received by the multiple receivers to be jointly equalized by the equalizer.

[0140] In some embodiments, the device is caused to cause multiple signals received by multiple receivers to be provided to an equalizer by causing, at each of the multiple receivers, serial-to-parallel conversion of the received signal to obtain multiple parallel signals, and providing the multiple parallel signals to the equalizer.

[0141] In certain embodiments, the apparatus is caused to cause joint equalization by causing joint equalization of a plurality of parallel signals from a plurality of receivers by an equalizer.

[0142] In some embodiments, the device is also caused to: cause multiple training signals to be sent from multiple transmitters to multiple receivers through multiple wavelength division multiplexing channels; and cause the multiple training signals received by the multiple receivers to be provided to an equalizer as input; and cause a training process to be performed by the equalizer using the multiple training signals received by the multiple receivers as input to the equalizer and using the multiple training signals sent by the multiple transmitters as outputs of the equalizer.

[0143] In certain embodiments, the apparatus is further caused to: cause time synchronization between the plurality of receivers; and cause time synchronization between the plurality of transmitters.

[0144] In some embodiments, the device is caused to cause time synchronization between multiple receivers by: causing a signal to be sent from one of the multiple transmitters to the multiple receivers; causing a reference time for time synchronization of the multiple receivers to be determined based on multiple reception time delays of the signals received by the multiple receivers; and causing time synchronization between the multiple receivers to be performed based on the reference time.

[0145] In some embodiments, the device is caused to cause time synchronization between multiple transmitters by: causing multiple signals to be sent from each of the multiple transmitters to one of the multiple receivers through a wavelength division multiplexing channel; causing a reference delay for time synchronization of the multiple transmitters to be determined based on multiple reception delays of the multiple receivers receiving the multiple signals from the multiple transmitters; and causing time synchronization between the multiple transmitters to be performed based on the reference delay.

Claims

1. A communication system, comprising: a plurality of transmitters configured to transmit a plurality of signals to a plurality of receivers via a plurality of wavelength division multiplexing channels; the plurality of receivers configured to provide the plurality of received signals to an equalizer coupled to the plurality of receivers; as well as The equalizer is configured to jointly equalize the multiple signals received by the multiple receivers, wherein the equalizer implements the joint equalization based on a neural network, and The plurality of receivers are configured to provide the plurality of received signals to the equalizer by: At each receiver of the plurality of receivers, Performing serial-to-parallel conversion on the received signal to obtain multiple parallel signals; as well as providing the plurality of parallel signals to the equalizer, and The equalizer is configured to perform the joint equalization by: jointly equalizing the multiple parallel signals from the multiple receivers.

2. The communication system according to claim 1, wherein The plurality of transmitters are further configured to transmit a plurality of training signals to the plurality of receivers through the plurality of wavelength division multiplexing channels; The plurality of receivers are further configured to provide the received plurality of training signals to the equalizer as input; and The equalizer is further configured to perform a training process using the plurality of training signals received by the plurality of receivers as input and using the plurality of training signals transmitted by the plurality of transmitters as output.

3. The communication system according to claim 1, wherein The plurality of transmitters are further configured to perform time synchronization between the plurality of transmitters; and The plurality of receivers are further configured to perform time synchronization among the plurality of receivers.

4. The communication system according to claim 3, wherein the plurality of receivers are further configured to: receiving a signal from a transmitter among the plurality of transmitters; determining a reference time for the time synchronization between the receivers based on a plurality of reception time delays of the signal received by the plurality of receivers; and The time synchronization among the plurality of receivers is performed based on the reference time.

5. The communication system according to claim 3, wherein the plurality of transmitters are further configured to: transmitting a signal in turn from each of the plurality of transmitters to one of the plurality of receivers via the wavelength division multiplexing channel; determining a reference delay for the time synchronization between the transmitters based on a plurality of reception delays at which the one of the plurality of receivers receives the plurality of signals from the plurality of transmitters; as well as The time synchronization among the plurality of transmitters is performed based on the reference delay.

6. A communication device, comprising: at least one processor; as well as at least one memory storing computer program code, The at least one memory and the computer program code are configured to, with the at least one processor, cause the communication device to: causing the plurality of transmitters to transmit the plurality of signals to the plurality of receivers via the plurality of wavelength division multiplexing channels; causing a plurality of signals received by the plurality of receivers to be provided to an equalizer coupled to the plurality of receivers; as well as causing the plurality of signals received by the plurality of receivers to be jointly equalized by the equalizer, wherein the equalizer implements the joint equalization based on a neural network, and wherein the communication device is caused to cause the plurality of signals received by the plurality of receivers to be provided to the equalizer by: causing, at each receiver in the plurality of receivers, Performing serial-to-parallel conversion on the received signal to obtain multiple parallel signals; and providing the plurality of parallel signals to the equalizer, and The communication device is caused to cause the equalizer to perform the joint equalization by: jointly equalizing the plurality of parallel signals from the plurality of receivers by the equalizer.

7. The communication device of claim 6, wherein the communication device is further caused to: causing a plurality of training signals to be transmitted from the plurality of transmitters to the plurality of receivers through the plurality of wavelength division multiplexing channels; and causing a plurality of training signals received by the plurality of receivers to be provided as input to the equalizer; and A training process is caused to be performed by the equalizer using the plurality of training signals received by the plurality of receivers as inputs of the equalizer and using the plurality of training signals transmitted by the plurality of transmitters as outputs of the equalizer.

8. The communication device of claim 6, wherein the communication device is further caused to: causing time synchronization among the plurality of receivers; and Time synchronization among the plurality of transmitters is caused.

9. The communication device of claim 8, wherein the communication device is caused to cause the time synchronization between the plurality of receivers by: causing a signal to be transmitted from a transmitter among the plurality of transmitters to the plurality of receivers; causing determination of a reference time for the time synchronization of the plurality of receivers based on a plurality of reception time delays of the plurality of receivers receiving the signal; and The time synchronization among the plurality of receivers is caused to be performed based on the reference time.

10. The communication device of claim 8, wherein the communication device is caused to cause the time synchronization between the plurality of transmitters by: causing a signal to be transmitted in turn from each of the plurality of transmitters to one of the plurality of receivers via the wavelength division multiplexing channel; causing determination of a reference delay for the time synchronization of the plurality of transmitters based on a plurality of reception delays at which the one of the plurality of receivers receives the plurality of signals from the transmitter; and The time synchronization among the plurality of transmitters is caused to be performed based on the reference delay.

11. A communication method, comprising: transmitting a plurality of signals from a plurality of transmitters to a plurality of receivers via a plurality of wavelength division multiplexed channels; providing a plurality of signals received by the plurality of receivers to an equalizer coupled to the plurality of receivers; as well as The plurality of signals received by the plurality of receivers are jointly equalized by the equalizer, wherein the equalizer implements the joint equalization based on a neural network, and Wherein providing the plurality of signals received by the plurality of receivers to the equalizer comprises: At each receiver of the plurality of receivers, Performing serial-to-parallel conversion on the received signal to obtain multiple parallel signals; and providing the plurality of parallel signals to the equalizer, and The performing of the joint equalization includes: performing, by means of the equalizer, joint equalization on the multiple parallel signals from the multiple receivers.

12. The communication method according to claim 11, further comprising: transmitting a plurality of training signals from the plurality of transmitters to the plurality of receivers through the plurality of wavelength division multiplexing channels; providing a plurality of training signals received by the plurality of receivers to the equalizer as input; as well as A training process is performed by the equalizer using the plurality of training signals received by the plurality of receivers as inputs of the equalizer and using the plurality of training signals transmitted by the plurality of transmitters as outputs of the equalizer.

13. The communication method according to claim 11, further comprising: performing time synchronization among the plurality of receivers; as well as Time synchronization is performed between the multiple transmitters.

14. The communication method according to claim 13, wherein performing the time synchronization on the plurality of receivers comprises: transmitting a signal from a transmitter among the plurality of transmitters to the plurality of receivers; Determining a reference time for the time synchronization of the multiple receivers based on multiple reception time delays of the multiple receivers receiving the signal; as well as The time synchronization among the plurality of receivers is performed based on the reference time.

15. The communication method according to claim 13, wherein performing the time synchronization on the plurality of transmitters comprises: transmitting a plurality of signals in turn from each of the plurality of transmitters to one of the plurality of receivers via the wavelength division multiplexing channel; determining a reference delay for the time synchronization of the plurality of transmitters based on a plurality of reception delays at which the one of the plurality of receivers receives the plurality of signals from the plurality of transmitters; as well as The time synchronization among the plurality of transmitters is performed based on the reference delay.

16. An apparatus comprising: means for transmitting a plurality of signals from a plurality of transmitters to a plurality of receivers via a plurality of wavelength division multiplexed channels; means for providing a plurality of signals received by the plurality of receivers to an equalizer coupled to the plurality of receivers; as well as means for jointly equalizing the plurality of signals received by the plurality of receivers by means of the equalizer, wherein the equalizer implements the joint equalization based on a neural network, and Wherein providing the plurality of signals received by the plurality of receivers to the equalizer comprises: At each receiver of the plurality of receivers, Performing serial-to-parallel conversion on the received signal to obtain multiple parallel signals; and providing the plurality of parallel signals to the equalizer, and The performing of the joint equalization includes: performing, by means of the equalizer, joint equalization on the multiple parallel signals from the multiple receivers.

17. A computer-readable storage medium having program instructions stored thereon, which instructions, when executed by a processor on a device, cause the device to: causing the plurality of transmitters to transmit the plurality of signals to the plurality of receivers via the plurality of wavelength division multiplexing channels; causing a plurality of signals received by the plurality of receivers to be provided to an equalizer coupled to the plurality of receivers; and causing the plurality of signals received by the plurality of receivers to be jointly equalized by the equalizer, wherein the equalizer implements the joint equalization based on a neural network, and wherein the apparatus is caused to cause the plurality of signals received by the plurality of receivers to be provided to the equalizer by: causing, at each receiver in the plurality of receivers, Performing serial-to-parallel conversion on the received signal to obtain multiple parallel signals; and providing the plurality of parallel signals to the equalizer, and Wherein the apparatus is caused to cause the equalizer to perform the joint equalization by: jointly equalizing, by the equalizer, the plurality of parallel signals from the plurality of receivers.

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