Transmitting device, receiving device and system suitable for three-phase power line carrier communication

Abstract

This application discloses a transmitting device, receiving device, and system suitable for three-phase power line carrier communication, belonging to the field of power line carrier communication technology. The transmitting device's transmitting end preprocessing module includes an SVD decomposition unit, a power allocation unit, and a spatial mapping unit. The SVD decomposition unit performs singular value decomposition on the channel matrix to obtain a unitary matrix, where the channel matrix originates from the channel state information of the power line carrier MIMO fed back by the receiving device. The power allocation unit determines the power allocation matrix according to a preset power allocation criterion. The spatial mapping unit generates a precoding matrix based on the unitary matrix and the power allocation matrix, and uses the precoding matrix to perform spatial mapping processing on the modulation symbol data to be transmitted before outputting it to the antenna port. In this way, the transmitted energy can be concentrated on the strong modes of the channel according to the real-time channel characteristics, effectively adapting to the attenuation imbalance and high spatial correlation of the power line carrier MIMO channel, improving channel capacity utilization and transmission reliability.

Description

Technical Field

[0001] This application relates to the field of carrier communication technology, and in particular to a transmitting device, receiving device and system suitable for three-phase power line carrier communication. Background Technology

[0002] Power line carrier communication (PLC) uses power lines to transmit data, eliminating the need for additional wiring, offering wide coverage and low cost. Low-voltage power lines typically consist of three conductors: a phase conductor, a neutral conductor, and a protective ground conductor. Multiple-input multiple-output (MIMO) technology utilizes combinations of these three conductors to enable multi-antenna transmission, thus overcoming the capacity and reliability bottlenecks of traditional single-input single-output systems.

[0003] Current three-phase power line carrier MIMO communication systems use a fixed spatial mapping matrix at the transmitting end to process the transmitted signal, mapping the spatial stream to the transmit antenna ports. This approach primarily utilizes antenna ports through simple port selection and fixed power allocation, without decomposing the channel matrix or dynamically adjusting precoding parameters based on channel state information. However, power line carrier MIMO channels exhibit characteristics such as unbalanced transmission loss, high spatial correlation, and time-varying channel characteristics, resulting in different channel attenuation for the spatial streams at each antenna port. In this situation, the fixed spatial mapping matrix cannot match the transmitted energy to the strong modes of the channel, leading to significant power differences among the receiver's streams. This reduces diversity gain or prevents proper detection of spatially multiplexed data streams, thus failing to fully utilize channel capacity. Summary of the Invention

[0004] This application provides a transmitting device, receiving device, and system suitable for three-phase power line carrier communication to solve at least one of the aforementioned technical problems.

[0005] The transmitting device for three-phase power line carrier communication according to the embodiments of this application includes a transmitting end preprocessing module, the transmitting end preprocessing module comprising: The SVD decomposition unit is used to perform singular value decomposition on the channel matrix to obtain a unitary matrix, wherein the channel matrix originates from the channel state information of power line carrier MIMO fed back by the receiving device. The power allocation unit is used to determine the power allocation matrix according to the preset power allocation criteria. The spatial mapping unit is used to generate a precoding matrix based on the unitary matrix and the power allocation matrix, and to perform spatial mapping processing on the modulation symbol data to be transmitted using the precoding matrix before outputting it to the antenna port.

[0006] In some implementations, the singular value decomposition is represented as:

[0007] in, The channel matrix; and All are unitary matrices; It is a diagonal matrix whose diagonal elements are singular values ​​of H; the unitary matrix output by the SVD decomposition unit is .

[0008] In some implementations, the preset power allocation criteria include at least one of the following: default power allocation criteria, power balance allocation criteria, power reversal allocation criteria, and water-filling algorithm allocation criteria; For the default power allocation criterion, the power allocation matrix is ​​used to keep the power ratio between each antenna port constant; For the power balance allocation criterion, the power allocation matrix is ​​used to make the transmission power of each spatial stream equal; For the power inversion allocation criterion, the power allocation matrix is ​​used to allocate power according to the inverse ratio of the gain of each spatial stream channel, so that the energy of each spatial stream signal reaching the receiving device is equal; For the water-filling algorithm allocation criterion, the power allocation matrix is ​​used to allocate power to each spatial flow according to the water-filling theorem under the total power constraint, so as to maximize the channel capacity.

[0009] In some implementations, the spatial mapping unit is used to left-multiply the antenna selection matrix by the power allocation matrix, and then left-multiply by the unitary matrix to obtain the precoding matrix.

[0010] In some implementations, the channel matrix is ​​fed back to the transmitting device by the receiving device in a periodic or aperiodic manner, and the transmitting end preprocessing module updates the precoding matrix in real time based on the fed-back channel matrix.

[0011] In some embodiments, the transmitting device supports multiple spatial mapping modes, including: In single-port mode, one antenna port in the three-phase power line conductor combination is selected for single-stream transmission. Two-port antenna diversity mode selects two antenna ports for single-stream diversity transmission; Three-port antenna diversity mode selects three antenna ports for single-stream diversity transmission; Two-port spatial multiplexing mode: Select two antenna ports for two-stream spatial multiplexing transmission; Three-port spatial multiplexing mode selects three antenna ports for two-stream spatial multiplexing transmission.

[0012] In some implementations, the spatial mapping unit is used to left-multiply the modulation symbol data by the precoding matrix to obtain a transmit signal, and output the transmit signal to each antenna port.

[0013] The receiving device for three-phase power line carrier communication according to the embodiments of this application includes a receiving end post-processing module, which is used for: The equivalent channel matrix is ​​obtained by right-multiplying the channel matrix by the precoding matrix generated in the transmitting device of any of the above embodiments. The received signal is detected and demodulated using the equivalent channel matrix to recover the transmitted data; Based on the power line carrier MIMO method, channel state information is fed back to the transmitting device.

[0014] In some implementations, the channel state information includes a channel transfer function and noise characteristic parameters, wherein the channel transfer function is used to construct the channel matrix.

[0015] The system applicable to three-phase power line carrier communication according to the embodiments of this application includes: The transmitting device of any of the above embodiments; and In any of the above embodiments, the transmitting device and the receiving device transmit signals based on power line carrier MIMO.

[0016] The transmitting apparatus, receiving apparatus, and system for three-phase power line carrier communication, as described in this application, employ a transmitting-end preprocessing module comprising an SVD decomposition unit, a power allocation unit, and a spatial mapping unit. This module performs singular value decomposition on the channel matrix derived from channel state information fed back from the receiving apparatus to obtain a unitary matrix, and combines this with the power allocation matrix to generate a precoding matrix for spatial mapping processing of the modulation symbol data. This allows for the concentration of transmission energy onto the strong modes of the channel based on real-time channel characteristics, effectively adapting to the attenuation imbalance and high spatial correlation of power line carrier MIMO channels, thereby improving channel capacity utilization and transmission reliability.

[0017] Additional aspects and advantages of embodiments of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of embodiments of this application. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, wherein: Figure 1 This is a schematic diagram of a system composition applicable to three-phase power line carrier communication according to certain embodiments of this application; Figure 2This is a schematic diagram of a system for three-phase power line carrier communication according to certain embodiments of this application; Figure 3 This is a schematic diagram of a transmitting device for three-phase power line carrier communication according to certain embodiments of this application.

[0019] Explanation of reference numerals in the attached figures: A transmitting device 100 suitable for three-phase power line carrier communication, a transmitting end preprocessing module 110, an SVD decomposition unit 10, a power allocation unit 20, a spatial mapping unit 30, a receiving device 200 suitable for three-phase power line carrier communication, a receiving end postprocessing module 210, and a system 1000 suitable for three-phase power line carrier communication. Detailed Implementation

[0020] The embodiments of this application will be further described below with reference to the accompanying drawings. The same or similar reference numerals in the drawings denote the same or similar elements or elements having the same or similar functions throughout. Furthermore, the embodiments of this application described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of this application, and should not be construed as limiting this application.

[0021] Power line carrier communication (PLC) uses power lines to transmit data, eliminating the need for additional wiring, offering wide coverage, and low cost. The core functions of the PLC physical layer are data encoding / decoding, modulation / demodulation, channel adaptation, and signal coupling. It also ensures reliable transmission under harsh power line conditions through frame synchronization, channel estimation, and interference mitigation.

[0022] The physical layer processing of a power line carrier communication system is described as follows. At the transmitter, a random 0 and 1 data payload bit stream is first generated. This is then channel-coded, and the encoded data stream undergoes constellation point mapping. Mapping methods can include Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), 16-Quadrature Amplitude Modulation (16QAM), and 64-Quadrature Amplitude Modulation (64QAM). If multi-layer transmission is supported, the complex symbols after constellation point mapping undergo layer mapping and precoding. Then, an Inverse Fast Fourier Transform (IFFT) is performed to obtain the time-domain signal. After adding a cyclic prefix and preamble, the signal is finally coupled to the power line for transmission, completing the physical layer process at the transmitter.

[0023] At the receiving end, after receiving the coupled signal from the power line, timing synchronization is first performed according to the preamble, the frame header of the data frame is found, the cyclic prefix is ​​removed and a Fast Fourier Transform (FFT) is performed, then the received signal and the channel estimation matrix are used to complete signal detection, and finally the obtained bits are channel decoded to obtain the corresponding information, thus completing the entire physical layer process.

[0024] The next-generation low-voltage power line broadband carrier communication system supports Multiple-Input Multiple-Output (MIMO) transmission with up to three antenna ports. A MIMO spatial mapper maps spatial streams to transmit ports. The system supports direct mapping and spatially extended mapping. Direct mapping directly maps the constellation points of each spatial stream to the transmit chain, achieving a one-to-one mapping. Spatial extension extends the constellation point vectors of all spatial streams through matrix multiplication, thereby generating the inputs for all transmit chains. By spatially mapping the symbols that have already undergone Orthogonal Frequency Division Multiplexing (OFDM) constellation mapping, the symbols input to the spatial mapping module are output to different transmit channels.

[0025] make This represents the input symbol for the j-th data stream of the sending port mapping module. Let represent the k-th output of the transmitting port mapping module. Then, the process of generating symbols in multiplexing mode through spatial mapping to the transmitting port is as follows:

[0026] The process of generating symbols in diversity mode by spatial mapping to the transmitting port is represented as follows:

[0027] in, This represents the spatial mapping matrix. Several spatial mapping matrices are defined to support antenna diversity and spatial multiplexing modes, as shown in Table 1 below. Antenna diversity includes three-port diversity, two-port diversity, and single-port mode (Single-Input Single-Output, SISO). Spatial multiplexing includes three-port spatial multiplexing and two-port spatial multiplexing.

[0028] Table 1 Spatial Mapping Matrix

[0029] The transmitting end multiplies the transmitted signal by the spatial mapping matrix:

[0030] in, The parameters are defined as follows: This represents the maximum number of antenna ports. ; Number of transmit antenna ports ; Number of receiving antennas ; For sending streams, .

[0031] The introduction of multi-antenna MIMO technology has effectively broken through the capacity and reliability bottlenecks of traditional SISO power line carrier systems, enabling power line carrier systems to meet the requirements of high-speed data transmission.

[0032] MIMO technology is one of the core technologies in communication. Essentially, it involves simultaneously configuring multiple antennas at both the transmitting and receiving ends. Utilizing spatial dimensions, it significantly improves system capacity, spectral efficiency, and link reliability without increasing spectrum bandwidth or transmit power. Key features include: Spatial multiplexing: High-speed data streams are split into multiple independent sub-streams, which are transmitted in parallel through different antennas. The receiver separates each sub-stream through a spatial equalization algorithm. The theoretical rate increases linearly with the number of antennas.

[0033] Spatial diversity: Multiple versions of the same data stream are transmitted / received through different antennas. Multiplexing or selective combining is used to reduce the probability of fading and improve transmission reliability.

[0034] Beamforming: Amplitude and phase weighting is applied to the feed of multiple antenna array elements to form a directional beam, which concentrates energy in the direction of the target user, suppresses interference to other users, and improves coverage and signal-to-interference-plus-noise ratio.

[0035] MIMO's diversity gain effectively combats multipath fading and impulse noise in power line carrier channels. By receiving signals through multiple antennas and combining signals from different paths, the impact of signal fading can be reduced, improving transmission reliability. In poor channel conditions, selecting appropriate signal detection algorithms can reduce computational complexity while maintaining performance. MIMO's spatial multiplexing gain can increase transmission rates within limited bandwidth. By simultaneously transmitting different signal streams through multiple antennas, it overcomes the rate limitations of SISO power line carrier systems, meeting the demands of high-speed data transmission.

[0036] MIMO transceiver modes support SISO, Multiple-Input Single-Output (MISO), Single-Input Multiple-Output (SIMO), and MIMO. Key technologies involved include: space-time / space-frequency coding to achieve diversity or multiplexing gain; acquiring and feeding back Channel State Information (CSI) using pilot signals, Sounding Reference Signals (SRS), and Channel State Information Reference Signals (CSI-RS) for precoding and adaptive modulation; precoding and signal detection techniques; and integration with OFDM.

[0037] In multi-antenna links, if the transmitter knows the channel state information (CSI), it can multiply the signal by a matrix W (precoding matrix) to concentrate energy on the strong modes of the channel while suppressing weak interference / noise modes. The receiver only needs simple processing to recover the data. By performing beamforming and interference suppression at the transmitter in advance through precoding, the signal-to-interference-plus-noise ratio (SINR) or bit error rate can be improved. Precoding can be divided into two categories depending on whether the transmitter knows the CSI: Closed-loop precoding: The transmitter obtains channel state information through uplink-downlink reciprocity or CSI-PMI feedback, and uses the channel state information to determine the precoding matrix.

[0038] Open-loop precoding: The transmitter does not need to know the instantaneous CSI, but uses a fixed / cyclic diversity codebook as the precoding matrix.

[0039] The current spatial mapping scheme uses a fixed spatial mapping matrix, as detailed in Table 1 above. This method does not require feedback of channel state information.

[0040] Research has revealed that power line carrier MIMO channels, relying on the inherent characteristics of power lines and combined with the MIMO multi-antenna architecture, form unique channel characteristics that combine the special features of power transmission media with the advantages of multi-antenna technology. Channel characteristics are highly dependent on the power line topology, cable parameters, and operating status, making the environment far more complex than that of wireless MIMO channels. The cable type, diameter, laying method, and length of the power line directly determine the channel's transmission loss and frequency response. Low-voltage power lines typically consist of three conductors: phase, neutral, and protective ground. MIMO technology utilizes the combination of these three conductors to achieve multi-antenna transmission; the differences in coupling characteristics between different conductors directly affect the stability of the channel matrix. Simultaneously, various electrical devices connected to power lines, such as household appliances and industrial loads, cause the channel impedance to exhibit time-varying characteristics. The starting and stopping of loads trigger impedance abrupt changes, leading to signal attenuation fluctuations, especially under heavy loads where the decrease in line impedance results in high attenuation of the carrier signal. Furthermore, distribution transformers act as obstructors for power line carrier signals, meaning that power line carrier MIMO signals can typically only be transmitted within the coverage area of ​​a single distribution transformer, limiting long-distance communication capabilities.

[0041] Considering the characteristics of power line carrier MIMO channels, current technologies mainly suffer from the following drawbacks: (1) Unable to flexibly cope with transmission loss and attenuation Power line carrier MIMO channels suffer from severe multipath effects. These effects arise from the complex structure of power line networks. Power line networks contain numerous branches, joints, loads, and cable bends, leading to multipath propagation during signal transmission. In addition to the main path signal, some signals are reflected and refracted through branch lines before reaching the receiver, resulting in multipath signal superposition. Compared to SISO systems, the multi-antenna configuration of MIMO architecture further increases the number of multipath signals, with significant differences in delay and amplitude between multipath signals received by different antennas, increasing the difficulty of signal detection. Power line carrier MIMO channels exhibit strong frequency-selective attenuation characteristics. Frequency-selective attenuation is a result of the combined effects of multipath effects and cable losses. Because power lines attenuate carrier signals of different frequencies to varying degrees, and the impact of multipath effects varies with frequency, significant quality differences occur across different subcarriers.

[0042] Current technology does not consider the signal attenuation differences between the three-phase combination forming MIMO antennas, but only selects to use some or all of the antenna ports by simply enabling or disabling them. As described in the aforementioned technical solution, spatial mapping matrix modes 4, 5, and 6 select a single antenna port; modes 1, 2, 3, 10, 11, and 12 select two antenna ports; and modes 0, 7, 8, and 9 select three antenna ports. The sequence numbers of each mode correspond to those in Table 1. The subscripts are consistent. Once a single or multiple antenna ports are selected, the power is fixed and allocated to the same value. If the spatial streams corresponding to each antenna port experience different MIMO channel attenuation, the signal power differences between the streams at the receiver will be large, which will reduce diversity gain or cause the spatially multiplexed data streams to fail to be detected correctly. Therefore, current transmission technologies are not suitable for power line carrier MIMO transmission channels with complex transmission losses and attenuation, and will reduce multi-antenna diversity gain or spatial multiplexing transmission efficiency.

[0043] (2) Unable to fully utilize channel capacity Spatial correlation is a key factor in the effectiveness of MIMO technology. The spatial correlation of power line carrier MIMO channels exhibits characteristics different from those of wireless MIMO channels, primarily stemming from the conductor layout and signal coupling mechanisms of power lines. Wireless MIMO channels have larger antenna spacing and lower spatial correlation, allowing for independent channel links through strategic antenna placement, thus maximizing diversity and multiplexing gains. However, the antennas in a power line carrier MIMO system are essentially combinations of different conductors in the power line, such as phase-neutral, phase-ground, and neutral-ground connections. These conductors are very closely spaced, resulting in strong signal coupling and high spatial correlation in the channel responses of different antenna links. This high spatial correlation reduces the channel capacity of the MIMO system, limiting the utilization of diversity and multiplexing gains. When spatial correlation is excessively high, the channel matrix rank of multiple antenna links decreases, making efficient signal multiplexing difficult. Furthermore, the spatial correlation of power line carrier MIMO channels is frequency-dependent, fluctuating with signal frequency; a highly correlated channel response reduces MIMO performance gains.

[0044] The current scheme uses a fixed power allocation method for the transmit antennas, without allocating power according to the singularity index (SISO), and the receiver does not perform corresponding post-processing. This transmit-receive method can only achieve maximum capacity when all parallel SISO channels have the same singularity value, i.e., when channel correlation is minimal. This does not conform to the actual MIMO channel conditions in real-world power line carrier applications. When antenna spatial correlation is high, channel capacity and diversity gain will decrease. Therefore, the current technical solution cannot fully leverage the core advantage of MIMO technology—that is, improving channel capacity through multiple antenna multiplexing.

[0045] (3) Unable to cope with dynamic time-varying channels The characteristics of power line carrier MIMO channels are not fixed but exhibit significant periodicity and time-varying properties, primarily stemming from the power frequency characteristics of the power system and the dynamic changes in electrical loads. The power frequency signal of the power system periodically interferes with the power line communication (PLC) signal, causing periodic variations in the impulse response and noise statistics of the MIMO channel. Furthermore, dynamic changes in electrical loads, such as the random start-up and shutdown of equipment in residential and industrial settings, lead to dynamic fluctuations in channel impedance and transmission loss over time, causing continuous changes in channel matrix parameters such as gain and phase, further reducing channel stability. This time-varying and periodic nature necessitates that the signal detection and channel estimation algorithms of power line carrier MIMO systems possess strong adaptive capabilities, capable of tracking channel changes in real time and adjusting algorithm parameters to ensure transmission reliability.

[0046] Current technical solutions are not suitable for MIMO channels that are periodic or time-varying. As seen in the aforementioned spatial mapping methods at the transmitter, current technology does not track channel changes and uses a fixed spatial mapping matrix to process the transmitted signal. The receiver also lacks processing procedures and methods that can match the time-varying channel. Once the channel undergoes dynamic changes, the current spatial mapping matrix may no longer be applicable, resulting in the inability to correctly detect spatial data upon arrival at the receiver.

[0047] (4) Performance is affected by noise and interference Power lines contain a large amount of complex noise, which directly superimposes on the MIMO transmission signal, severely affecting channel quality. The noise characteristics of power line carrier MIMO channels are more complex than those of wireless channels, mainly falling into two categories: one is background noise such as thermal noise and line leakage noise, which has relatively stable amplitude and follows a Gaussian distribution; the other is impulse noise, the most representative noise type in power line carrier channels, generated by the starting and stopping of electrical equipment, power switch operations, etc., characterized by suddenness, short duration, and high amplitude, and usually exhibiting a non-Gaussian distribution. In addition, the noise in broadband power line carrier systems also exhibits spatial correlation and cyclic stationarity, forming a complex multivariate noise process.

[0048] Current technical solutions do not consider the noise differences between multiple antennas, nor can they track changes in channel interference. In practical MIMO architectures, when multiple antennas receive signals simultaneously, they capture noise and interference from different paths, and the noise from different antennas may be correlated. The suddenness of impulse noise can cause a sharp increase in the signal bit error rate, especially in high-order modulation scenarios, placing higher demands on signal detection algorithms. Current technical solutions cannot suppress interference / noise by allocating power through preprocessing at the transmitting end and postprocessing at the receiving end.

[0049] In summary, the power line carrier MIMO channel is a complex channel that combines the transmission characteristics of power lines with the advantages of MIMO technology. It exhibits strong medium dependence, significant multipath effects and frequency-selective attenuation, unique spatial correlation, complex and non-Gaussian noise, periodic and time-varying channel characteristics, and capacity limited by line characteristics. While current technologies achieve multi-antenna diversity and multiplexing, they are limited in application scenarios within complex power line carrier MIMO channels, failing to fully achieve the desired improvements in bit error rate performance or transmission efficiency. Therefore, considering the characteristics of power line carrier MIMO channels and combining them with the actual needs of power scenarios, optimizing the design of three-phase power line carrier communication systems is crucial to fully leveraging the advantages of power line carrier MIMO technology.

[0050] In view of this, embodiments of this application provide an apparatus and system suitable for three-phase power line carrier communication. By rationally utilizing the core advantages of MIMO technology, the transmission performance of the power line carrier system can be effectively improved or the spectrum utilization rate can be increased. The apparatus and system of this application support SISO, antenna diversity, and spatial multiplexing.

[0051] The system 1000 for three-phase power line carrier communication according to the embodiments of this application includes a transmitting device 100 and a receiving device 200 of the power line carrier physical layer, and the system structure is as follows: Figure 1 As shown. The transmitting device 100 generates an OFDM signal and transmits it to the receiving device 200 via a power line carrier MIMO channel. The receiving device 200 receives and detects the signal. The receiving device 200 feeds back channel state information to the transmitting device 100 in a periodic or aperiodic manner. The transmitting device 100 adjusts parameters based on the CSI feedback.

[0052] Please see Figures 1 to 3 The transmitting apparatus 100 for three-phase power line carrier communication according to this application includes a transmitting end preprocessing module 110. The transmitting end preprocessing module 110 includes an SVD decomposition unit 10, a power allocation unit 20, and a spatial mapping unit 30. The SVD decomposition unit 10 performs singular value decomposition on the channel matrix to obtain a unitary matrix, wherein the channel matrix originates from the channel state information of the power line carrier MIMO fed back by the receiving device 200. The power allocation unit 20 determines the power allocation matrix according to a preset power allocation criterion. The spatial mapping unit 30 generates a precoding matrix based on the unitary matrix and the power allocation matrix, and performs spatial mapping processing on the modulation symbol data to be transmitted using the precoding matrix before outputting it to the antenna port.

[0053] Specifically, the transmitting device 100 can be applied to three-phase power line carrier MIMO communication scenarios. The low-voltage power line can contain three conductors: a phase conductor, a neutral conductor, and a protective ground conductor. By utilizing different combinations of these three conductors to form multiple antenna ports, MIMO multi-antenna transmission can be achieved.

[0054] The transmitting device 100 includes a transmitting end preprocessing module 110, which consists of three functional units: an SVD decomposition unit 10, a power allocation unit 20, and a spatial mapping unit 30. The three functional units work together to complete the spatial mapping preprocessing from the data stream to the antenna port.

[0055] In the embodiments of this application, the processing flow of the transmitting end preprocessing module 110 may include three steps executed sequentially. First, the SVD decomposition unit 10 performs Singular Value Decomposition (SVD) on the channel matrix to obtain a unitary matrix. The channel matrix originates from the channel state information of the power line carrier MIMO fed back by the receiving device 200. The channel state information reflects the transmission characteristics of the current power line carrier MIMO channel, including transmission loss, attenuation, and channel spatial correlation information between antenna ports. By performing singular value decomposition on the channel matrix, the SVD decomposition unit 10 can extract the spatial features of the channel, providing a basis for subsequent precoding processing.

[0056] The second step involves the power allocation unit 20 determining the power allocation matrix based on preset power allocation criteria. These criteria can be selected and configured according to the specific application scenario. The power allocation matrix is ​​used to adjust the transmission power of each spatial stream to accommodate the attenuation imbalance between antenna ports in a power line carrier MIMO channel.

[0057] Third, the spatial mapping unit 30 generates a precoding matrix based on the unitary matrix output by the SVD decomposition unit 10 and the power allocation matrix determined by the power allocation unit 20. The spatial mapping unit 30 uses this precoding matrix to perform spatial mapping processing on the modulation symbol data to be transmitted, and outputs the processed signal to each antenna port for transmission. The modulation symbol data to be transmitted can be complex symbols obtained after channel coding and constellation point mapping. Constellation point mapping methods can include BPSK, Quadrature Phase Shift Keying (QPSK), 16QAM, and 64QAM, etc. After spatial mapping processing, the signal is coupled to the power line for transmission after IFFT at each antenna port.

[0058] In the embodiments of this application, the transmitting device 100 can support three transmission modes: SISO, antenna diversity, and spatial multiplexing. For single-stream transmission mode, the data stream does not need to be stream-mapped; for multi-stream transmission mode, the source data needs to be divided into multiple spatial streams, and then spatially mapped by the transmitting end preprocessing module 110.

[0059] This embodiment of the application establishes a transmitter preprocessing module 110 comprising an SVD decomposition unit 10, a power allocation unit 20, and a spatial mapping unit 30. This module performs singular value decomposition on the channel matrix derived from the channel state information fed back from the receiver 200 to obtain a unitary matrix, and combines this with the power allocation matrix to generate a precoding matrix for spatial mapping processing of the modulation symbol data. In this way, the transmitted energy can be concentrated on the strong modes of the channel based on real-time channel characteristics, effectively adapting to the attenuation imbalance and high spatial correlation of power line carrier MIMO channels, thereby improving channel capacity utilization and transmission reliability.

[0060] In some implementations, singular value decomposition is represented as:

[0061] in, The channel matrix; and All are unitary matrices; It is a diagonal matrix whose diagonal elements are the singular values ​​of H; the unitary matrix output by SVD decomposition unit 10 is .

[0062] Specifically, the channel matrix Characterizes the channel transfer function between each transmit antenna port and each receive antenna in a power line carrier MIMO channel. For the channel matrix After performing singular value decomposition, a left unitary matrix can be obtained. diagonal array and right unitary matrix conjugate transpose Among them, the diagonal array The diagonal elements are non-negative real numbers. , is the channel matrix The singular values ​​of the channel matrix can be arranged in descending order. The magnitude of the singular values ​​reflects the channel gain strength in the corresponding spatial direction of the channel matrix. Larger singular values ​​correspond to spatial modes with stronger channel gain, while smaller singular values ​​correspond to spatial modes with weaker channel gain.

[0063] In the embodiments of this application, the unitary matrix output by the SVD decomposition unit 10 is a right unitary matrix. This matrix is ​​used in subsequent spatial mapping unit 30 to generate the precoding matrix. Right unitary matrix. The column vectors can form a channel matrix. The right singular vector represents the optimal beam direction at the transmitter. This is achieved by using the right unitary matrix... As the basic matrix for precoding, it can map the modulation symbol data to be transmitted onto the various feature space directions of the channel, so that the transmitted energy is transmitted along the direction with the strongest channel gain.

[0064] In some embodiments, for a three-port spatial multiplexing mode, the channel matrix Take the channel transfer function corresponding to all 3 columns, and the unitary matrix obtained after SVD decomposition. It is a 3×2 or 3×3 matrix; for two-port spatial multiplexing mode, the channel matrix is... Take the two columns of channel transfer function corresponding to each mode, and the unitary matrix obtained after SVD decomposition. It is a 2×2 dimensional matrix. For single-stream transmission mode, no SVD decomposition is performed, and the corresponding unitary matrix is... Set it to be the identity matrix.

[0065] In the embodiments of this application, the right unitary matrix contained in the precoding matrix at the transmitting end is used. By processing the transmitted signal and then processing the received signal accordingly at the receiving end using a post-processing module, a MIMO channel can be equivalent to multiple virtual single-input single-output (SIO) channels. The capacity of a MIMO channel is equal to the sum of the capacities of each virtual SIO channel. By comparing the capacities of each virtual SIO channel, different modulation orders can be selected or configured for use, thereby improving detection performance or spectral efficiency.

[0066] The embodiments of this application extract channel spatial features by performing singular value decomposition on the channel matrix and using the right unitary matrix as the precoding basis. This enables the transmitted signal to be aligned with the strong mode direction of the channel, realizing the equivalent conversion of the MIMO channel to multiple virtual single-input single-output channels, making full use of the channel capacity in each spatial direction, and improving the transmission efficiency of the power line carrier MIMO system.

[0067] In some implementations, the preset power allocation criteria include at least one of the following: default power allocation criteria, power balance allocation criteria, power reversal allocation criteria, and water injection algorithm allocation criteria.

[0068] For the default power allocation criterion, the power allocation matrix is ​​used to keep the power ratio between each antenna port constant. For the power balance allocation criterion, the power allocation matrix is ​​used to make the transmission power of each spatial stream equal; For the power inversion allocation criterion, the power allocation matrix is ​​used to allocate power according to the inverse ratio of the gain of each spatial stream channel, so that the energy of each spatial stream signal reaching the receiving device 200 is equal. For the water-filling algorithm allocation criteria, the power allocation matrix is ​​used to allocate power to each spatial flow according to the water-filling theorem under the total power constraint, so as to maximize the channel capacity.

[0069] Specifically, the power allocation unit 20 can select one or more of the above power allocation criteria for configuration according to the needs of the actual application scenario. Different power allocation criteria are suitable for different channel conditions and transmission requirements, so as to adapt to the attenuation differences and channel quality fluctuations between antenna ports in the power line carrier MIMO channel.

[0070] In some embodiments, a default power allocation criterion is employed. The power allocation matrix is ​​an identity matrix with normalized coefficients, meaning that the power ratios between spatial flows are not adjusted, and the power ratios between antenna ports remain constant. The normalized coefficients can be determined by calculating the norm of the spatial mapping matrix to satisfy the total transmit power constraint. For example, for a three-port antenna diversity mode, the normalized coefficients could be... For a two-port antenna diversity mode, the normalization coefficient can be... For single-port mode, the normalization coefficient can be 1; for two-port space multiplexing mode, the normalization coefficient can be... For the three-port spatial multiplexing mode, the normalization coefficient can be calculated and determined based on the norm of the corresponding spatial mapping matrix. This criterion is applicable to scenarios where channel conditions are relatively stable and the attenuation differences between antenna ports are small.

[0071] In some embodiments, a power balance allocation criterion is employed. The power allocation matrix is ​​used to ensure that the transmission power of each spatial stream is equal. In three-port spatial multiplexing mode, the transmitting device 100 supports two-stream spatial multiplexing transmission. After singular value decomposition, the singular values ​​corresponding to the two spatial streams are usually not equal, resulting in an imbalance in the transmission power of the two streams after spatial mapping. The power balance allocation criterion, through the power allocation matrix, can simultaneously achieve power normalization and power balance between the two streams, ensuring that the transmission power of the two spatial streams is equal. This criterion is suitable for scenarios where it is necessary to ensure that each spatial stream has the same transmission power at the transmitting end, and can avoid situations where the signal quality of one spatial stream at the receiving end is significantly inferior to that of the other spatial stream due to excessive differences in transmission power.

[0072] In some embodiments, a power inversion allocation criterion is employed. The power allocation matrix is ​​used to allocate power according to the inverse ratio of the gain of each spatial stream channel, so that the energy of each spatial stream signal arriving at the receiving device 200 is equal. The power allocation criterion can be a diagonal matrix obtained from singular value decomposition. The magnitude of each singular value is considered. A larger transmission power is allocated to spatial streams with lower channel gain (i.e., smaller singular values), and a smaller transmission power is allocated to spatial streams with higher channel gain (i.e., larger singular values), ensuring that the signal energy reaching the receiver 200 after transmission through the channel is relatively uniform. This criterion is applicable to scenarios with significant differences in channel attenuation between spatial streams, effectively offsetting channel attenuation imbalances and reducing the bit error rate of data detection at the receiver.

[0073] In some embodiments, a water-filling algorithm is employed for power allocation. The power allocation matrix is ​​used to allocate power to each spatial stream according to the water-filling theorem under a total power constraint, thereby maximizing channel capacity. The principle of the water-filling theorem is to allocate more transmission power to spatial streams with better channel quality (i.e., larger singular values ​​and higher signal-to-noise ratio), and less transmission power or no power to spatial streams with poorer channel quality (i.e., smaller singular values ​​and lower signal-to-noise ratio). Under the condition of limited total transmit power, solving for the optimal power allocation value for each spatial stream using the water-filling algorithm can maximize the overall channel capacity of the system. This criterion is applicable to scenarios requiring maximum system throughput and spectral efficiency, and can fully exploit the transmission potential of power line carrier MIMO channels.

[0074] The embodiments of this application provide multiple power allocation criteria, enabling the transmitting device 100 to flexibly select a power allocation strategy based on the actual attenuation characteristics and transmission requirements of the power line carrier MIMO channel, thereby achieving a reasonable allocation of transmission power, effectively adapting to the attenuation imbalance characteristics between antenna ports in the power line carrier MIMO channel, and improving transmission reliability or channel capacity utilization.

[0075] In some implementations, the space mapping unit 30 is used to left-multiply the antenna selection matrix by the power allocation matrix, and then left-multiply by the unitary matrix to obtain the precoding matrix.

[0076] Specifically, the process of generating the precoding matrix by the space mapping unit 30 can be as follows: First, obtain the antenna selection matrix, which is used to determine the antenna port combination selected in the current space mapping mode; then, multiply the antenna selection matrix by the power allocation matrix determined by the power allocation unit 20 to obtain the intermediate matrix; finally, multiply the intermediate matrix by the unitary matrix output by the SVD decomposition unit 10. This yields the final precoding matrix.

[0077] In the embodiments of this application, the antenna selection matrix corresponds to various spatial mapping modes supported by the transmitting device 100. The three conductors of a three-phase power line can be combined to form up to three antenna ports, and the dimension and structure of the antenna selection matrix can be determined by the currently selected spatial mapping mode. For a three-port mode, the antenna selection matrix selects all three antenna ports; for a two-port mode, the antenna selection matrix selects a combination of two antenna ports; and for a single-port mode, the antenna selection matrix selects one antenna port.

[0078] In some embodiments, the generation of the precoding matrix can be represented as:

[0079] in, For the precoding matrix, The unitary matrix output by SVD decomposition unit 10. For the power allocation matrix, This is the antenna selection matrix. Through the matrix operations, the precoding matrix simultaneously contains channel spatial characteristic information, power allocation information, and antenna port selection information, achieving a complete mapping from spatial flow to antenna ports.

[0080] In the embodiments of this application, for single-stream transmission mode, SVD decomposition may not be performed, and the unitary matrix may be omitted. Assuming an identity matrix, the precoding matrix degenerates into the product of the power allocation matrix and the antenna selection matrix, enabling direct mapping from a single stream to the selected antenna port. For multi-stream spatial multiplexing modes, the unitary matrix... Carrying channel spatial characteristic information, the precoding matrix can align the signals of each spatial stream with the characteristic directions of the channel for transmission.

[0081] The embodiments of this application generate a precoding matrix by sequentially left-multiplying the antenna selection matrix by the power allocation matrix and the unitary matrix. This integrates channel spatial feature adaptation, power allocation adjustment, and antenna port selection into the precoding matrix, simplifying the transmitting end processing flow while ensuring that the transmitted signal can adapt to the spatial characteristics of the power line carrier MIMO channel and improving transmission performance.

[0082] In some implementations, the channel matrix is ​​fed back to the transmitting device 100 by the receiving device 200 in a periodic or aperiodic manner. The transmitting end preprocessing module 110 updates the precoding matrix in real time based on the fed-back channel matrix.

[0083] Specifically, the characteristics of a power line carrier MIMO channel are not fixed but exhibit significant time-varying properties. The power frequency signal of the power system periodically interferes with the carrier signal, causing periodic changes in the impulse response and noise statistics of the MIMO channel. Furthermore, dynamic changes in the electrical load cause the channel impedance and transmission loss to fluctuate dynamically over time, resulting in continuous changes in the parameters of the channel matrix. Therefore, the receiving device 200 needs to feed back the real-time acquired channel state information to the transmitting device 100 so that the transmitting end preprocessing module 110 can track the dynamic changes of the channel.

[0084] In some embodiments, the receiving device 200 feeds back the channel matrix to the transmitting device 100 periodically. Periodic feedback means that the receiving device 200 periodically sends channel state information to the transmitting device 100 at preset fixed time intervals. This method is suitable for scenarios where the power line carrier MIMO channel changes in a certain regularity, such as when the channel characteristics fluctuate periodically due to the influence of the power system's power frequency cycle. The feedback period can be configured according to the time-varying characteristics of the power line channel; a shorter feedback period is used when the channel changes rapidly, and a longer feedback period is used when the channel changes slowly.

[0085] In some embodiments, the receiving device 200 feeds back the channel matrix to the transmitting device 100 in an aperiodic manner. Aperiodic feedback means that the receiving device 200 triggers feedback based on actual changes in the channel state, rather than at fixed time intervals. For example, when the receiving device 200 detects a significant change in channel characteristics, it actively feeds back updated channel state information to the transmitting device 100. This method is suitable for scenarios where the power line carrier MIMO channel experiences abrupt changes due to factors such as random start-up and shutdown of electrical equipment, and can promptly update the precoding parameters at the transmitting end when the channel changes abruptly.

[0086] In the embodiments of this application, the transmitting end preprocessing module 110 updates the precoding matrix in real time based on the channel matrix fed back by the receiving device 200. Specifically, the process can be as follows: the SVD decomposition unit 10 re-performs singular value decomposition on the updated channel matrix to obtain a new unitary matrix; the power allocation unit 20 redetermines the power allocation matrix; and the spatial mapping unit 30 regenerates the precoding matrix based on the new unitary matrix and the power allocation matrix. Through this real-time update process, the precoding matrix of the transmitting device 100 always matches the current channel state, ensuring that the transmitted signal can adapt to the dynamically changing power line carrier MIMO channel.

[0087] In this embodiment, the receiving device 200 feeds back the channel matrix in a periodic or non-periodic manner, and the precoding matrix is ​​updated in real time by the transmitting end preprocessing module 110. This enables the transmitting device 100 to track the time-varying characteristics of the power line carrier MIMO channel and adjust the precoding parameters in a timely manner when the channel changes dynamically, ensuring the correct detection of transmitted data at the receiving end.

[0088] In some embodiments, the transmitting device 100 supports multiple spatial mapping modes, including: In single-port mode, one antenna port in the three-phase power line conductor combination is selected for single-stream transmission. Two-port antenna diversity mode selects two antenna ports for single-stream diversity transmission; Three-port antenna diversity mode selects three antenna ports for single-stream diversity transmission; Two-port spatial multiplexing mode: Select two antenna ports for two-stream spatial multiplexing transmission; Three-port spatial multiplexing mode selects three antenna ports for two-stream spatial multiplexing transmission.

[0089] Specifically, a three-phase low-voltage power line can consist of three conductors: a phase conductor, a neutral conductor, and a protective ground conductor. Antenna ports are formed through different combinations of these three conductors. Maximum number of antenna ports. The number 3 corresponds to different combinations of the three conductors. The transmitting device 100 selects one of the aforementioned spatial mapping modes for data transmission based on the current channel conditions and transmission requirements.

[0090] In some embodiments, a single-port mode is employed. The transmitting device 100 can select one antenna port from the three-phase power line conductor combination for single-stream transmission, and the number of transmitting antenna ports... =1, number of streams sent The value is 1. This mode corresponds to a single-input single-output transmission method, suitable for scenarios with poor channel conditions or where only low-speed transmission is required. Any one of the three antenna ports can be selected; the specific antenna port chosen depends on the channel quality of each port.

[0091] In some embodiments, a two-port antenna diversity mode is employed. The transmitting device 100 can select two of the three antenna ports for single-stream diversity transmission, and the number of transmitting antenna ports... The number of sent streams is 2. The value is 1. The same data stream is transmitted simultaneously through two antenna ports. Diversity gain is obtained by utilizing the different channel fading characteristics experienced by the two antenna ports, reducing the impact of signal fading and improving transmission reliability. The two-port antenna diversity mode includes three antenna port combination methods, each corresponding to a different combination of selecting two antenna ports from the three antenna ports.

[0092] In some embodiments, a three-port antenna diversity mode is employed. The transmitting device 100 can select all three antenna ports for single-stream diversity transmission, and the number of transmitting antenna ports... The number of sent streams is 3. The value is 1. The same data stream is transmitted simultaneously through three antenna ports, and the maximum diversity gain is achieved by utilizing the spatial diversity among the three antenna ports. Compared with the two-port antenna diversity mode, the three-port antenna diversity mode can provide a higher-order diversity gain, further improving transmission reliability. It is suitable for scenarios with severe channel fading and high requirements for transmission reliability.

[0093] In some embodiments, a two-port spatial multiplexing mode is employed. The transmitting device 100 can select two of its three antenna ports for two-stream spatial multiplexing transmission, and the number of transmitting antenna ports... Number of streams sent The two-port spatial multiplexing mode divides the source data into two independent spatial streams, which are transmitted in parallel through two antenna ports. The receiving end uses a signal detection algorithm to separate the spatial streams and recover the data. This mode improves the transmission rate through spatial multiplexing and is suitable for scenarios with good channel conditions and high data throughput requirements. The two-port spatial multiplexing mode includes three antenna port combination methods.

[0094] In some embodiments, a three-port spatial multiplexing mode is employed. The transmitting device 100 selects all three antenna ports for two-stream spatial multiplexing transmission, and the number of transmitting antenna ports... The number of sent streams is 3. The three-port spatial multiplexing mode divides the source data into two independent spatial streams, which are transmitted through three antenna ports. Compared to the two-port spatial multiplexing mode, the three-port spatial multiplexing mode utilizes additional antenna ports to provide additional spatial degrees of freedom. While achieving spatial multiplexing gain, it can also obtain a certain degree of diversity gain, making it suitable for scenarios that require a balance between transmission rate and reliability.

[0095] The embodiments of this application support multiple spatial mapping modes, enabling the transmitting device 100 to flexibly select the number of antenna ports and the transmission mode according to the actual conditions of the power line carrier MIMO channel, and obtain diversity gain or spatial multiplexing gain in different channel environments to meet the differentiated requirements for transmission reliability or transmission rate in different scenarios.

[0096] In some implementations, the spatial mapping unit 30 is used to left-multiply the modulation symbol data by the precoding matrix to obtain the transmitted signal, and output the transmitted signal to each antenna port.

[0097] Specifically, the spatial mapping unit 30 can perform matrix multiplication as the specific operation for spatial mapping processing. Let the modulation symbol data to be transmitted be represented as... The precoding matrix is ​​represented as The output of the spatial mapping unit 30, i.e. the transmitted signal, is expressed as:

[0098] in, This is the transmitted signal vector after spatial mapping processing. The modulation symbol data vector to be transmitted. This is the precoding matrix.

[0099] In the embodiments of this application, for single-stream transmission mode, the modulation symbol data For scalars, the precoding matrix The result of matrix multiplication for column vectors This is a vector with the same dimension as the number of transmit antenna ports, where each element corresponds to the transmitted signal from each antenna port. For a two-stream spatial multiplexing transmission mode, the modulation symbol data... It is a 2×1 dimensional vector containing modulation symbols from two spatial streams, and the precoding matrix. The number of columns is 2, and the result of matrix multiplication is... It is a vector with the same dimension as the number of transmit antenna ports.

[0100] In the embodiments of this application, the transmitted signal vector Each component corresponds to the input signal at each antenna port. The spatial mapping unit 30 maps the transmitted signal... Each component is output to the corresponding antenna port. Each antenna port performs OFDM modulation processing on its own input signal, that is, performs inverse fast Fourier transform and adds a cyclic prefix, and then couples it to the power line for transmission.

[0101] Due to the precoding matrix By integrating information from the unitary matrix, power allocation matrix, and antenna selection matrix, the spatial mapping unit 30 can simultaneously complete the three processes of channel spatial feature adaptation, power allocation, and antenna port mapping with a single matrix multiplication operation, without needing to perform multiple operations in steps.

[0102] The embodiments of this application achieve spatial mapping processing by left-multiplying the modulation symbol data by the precoding matrix, integrating multiple preprocessing functions into a single matrix operation. This simplifies the calculation process and reduces the processing complexity of the transmitting device 100 while ensuring that the transmitted signal adapts to the channel spatial characteristics.

[0103] Please see Figure 1 and Figure 2 The receiving device 200 for three-phase power line carrier communication according to the embodiments of this application includes a receiving end post-processing module 210. The receiving end post-processing module 210 is used to: multiply the channel matrix by the precoding matrix generated in the transmitting device 100 of any of the above embodiments to obtain an equivalent channel matrix; use the equivalent channel matrix to perform data detection and demodulation on the received signal to recover the transmitted data; and feed back the channel state information to the transmitting device 100 based on the power line carrier MIMO method.

[0104] Specifically, the receiving device 200 can be applied to three-phase power line carrier MIMO communication scenarios, working in conjunction with the aforementioned transmitting device 100 to form a complete preprocessing-transmission-postprocessing closed loop. After receiving the coupled signal from the power line, the receiving device 200 completes the signal processing operations matching those of the transmitting preprocessing module 110 through the receiving end postprocessing module 210.

[0105] In embodiments of this application, the processing flow of the receiver post-processing module 210 may include the following steps. The first step is to right-multiply the channel matrix by the precoding matrix generated in the transmitting device 100. This yields the equivalent channel matrix. Let the channel matrix be... The precoding matrix is The equivalent channel matrix is ​​then expressed as:

[0106] Equivalent channel matrix The actual MIMO channel and the effect of precoding at the transmitting end are combined into an equivalent channel, which reflects the comprehensive transmission characteristics of each spatial stream after precoding when it arrives at the receiving end.

[0107] In the embodiments of this application, the signal received by the receiving device 200 is represented as follows:

[0108] in, For the received signal vector, For the channel matrix, The transmitted signal vector, For noise vectors, For the precoding matrix, Let be the modulation symbol data vector to be transmitted. By constructing an equivalent channel matrix, the receiver post-processing module 210 transforms the MIMO detection problem into a signal detection problem based on the equivalent channel.

[0109] The second step is to utilize the equivalent channel matrix. The received signal is detected and demodulated to recover the transmitted data. The receiver post-processing module 210 is based on the equivalent channel matrix. For the received signal Perform signal detection, separate and recover the modulation symbol data corresponding to each spatial stream. Since the transmitter has converted the MIMO channel into multiple virtual single-input single-output channels through singular value decomposition-based precoding, the processing complexity of detection at the receiver using the equivalent channel matrix is ​​reduced. The recovered modulation symbol data is then subjected to constellation point mapping and channel decoding to finally obtain the original information bits.

[0110] Third, based on the power line carrier MIMO method, the channel state information is fed back to the transmitting device 100. The receiving device 200 feeds back the channel state information to the transmitting device 100 through the power line carrier communication link, enabling the transmitting end preprocessing module 110 to obtain the current channel characteristics and generate or update the precoding matrix accordingly. This feedback process enables the transmitting and receiving ends to cooperate and adapt, with the transmitting end precoding parameters and the receiving end postprocessing parameters linked in real time.

[0111] In some embodiments, after receiving a coupled signal from a power line, the receiving device 200 first performs timing synchronization based on a preamble symbol to determine the frame header position of the data frame, removes the cyclic prefix, performs FFT to obtain the frequency domain signal, and then the receiving end post-processing module 210 uses the equivalent channel matrix to complete signal detection. Finally, the detected bit sequence is channel decoded to recover the original information.

[0112] In this embodiment, the receiver post-processing module 210 multiplies the channel matrix by the precoding matrix to obtain an equivalent channel matrix, and uses the equivalent channel matrix to perform data detection and demodulation, thereby achieving reception processing that matches the preprocessing at the transmitter. At the same time, the channel state information is fed back to the transmitter device 100 to form a closed-loop adaptation, effectively improving the transmission reliability and detection performance of the power line carrier MIMO system in complex time-varying channel environments.

[0113] In some implementations, channel state information includes the channel transfer function and noise characteristic parameters. The channel transfer function is used to construct the channel matrix.

[0114] Specifically, the channel state information fed back from the receiving device 200 to the transmitting device 100 may include two parts: the channel transfer function and noise characteristic parameters. The channel transfer function describes the transmission characteristics between each transmit antenna port and each receive antenna in the power line carrier MIMO channel, including the amplitude response and phase response of each path. The noise characteristic parameters describe the noise statistical characteristics in the power line carrier MIMO channel.

[0115] In the embodiments of this application, the channel transfer function is used to construct the channel matrix. The receiving device 200 can obtain the channel transfer function on each subcarrier between each transmit antenna port and each receive antenna through channel estimation, and arrange and combine these channel transfer functions according to the correspondence between the antenna ports to construct a channel matrix. Channel matrix The number of rows corresponds to the number of receiving antennas. The column number corresponds to the number of transmit antenna ports. Each element in the matrix represents the channel transfer function value between the corresponding transmit and receive antenna pairs. The completed channel matrix... Used for singular value decomposition by SVD decomposition unit 10.

[0116] In the embodiments of this application, noise characteristic parameters reflect the statistical characteristics of noise in the power line carrier MIMO channel. It is understood that various types of noise exist in the power line carrier channel, including background noise and impulse noise. Background noise has a relatively stable amplitude and exhibits a Gaussian distribution; impulse noise is generated by the starting and stopping of electrical equipment, power switch operations, etc., and is characterized by suddenness, short duration, and high amplitude, exhibiting a non-Gaussian distribution. Furthermore, when multiple antennas receive signals simultaneously, there may be spatial correlation between the noise from different antennas. Noise characteristic parameters include information such as the noise power on each receiving antenna and the spatial correlation characteristics of the noise.

[0117] In some embodiments, the power allocation unit 20 of the transmitting device 100 can use noise characteristic parameters to help determine the power allocation strategy, i.e., the power allocation criterion. When the noise characteristic parameters fed back by the receiver indicate that the noise or interference is strong in certain spatial directions, the power allocation unit 20 can correspondingly reduce the transmission power allocated in that direction, and concentrate the energy on the channel space with a higher signal-to-interference-plus-noise ratio, thereby improving the bit error rate performance of the system in complex noise and interference environments.

[0118] The embodiments of this application include channel transfer function and noise characteristic parameters in the channel state information, so that the transmitting device 100 can not only obtain the transmission characteristics of the channel for spatial characteristic adaptation, but also obtain noise and interference information to optimize the power allocation strategy, thereby achieving comprehensive adaptation of the transmission characteristics and noise characteristics of the power line carrier MIMO channel and improving the system's anti-interference capability in complex noise environments.

[0119] Please see Figure 1 and Figure 2 The system 1000 for three-phase power line carrier communication according to the embodiments of this application includes a transmitting device 100 and a receiving device 200 as described in any of the above embodiments. The transmitting device 100 and the receiving device 200 transmit signals based on power line carrier MIMO.

[0120] Specifically, this system can be applied to three-phase low-voltage power line carrier broadband communication scenarios. A low-voltage power line can contain three conductors: a phase conductor, a neutral conductor, and a protective ground conductor. The system utilizes the combinations of these three conductors to form multiple antenna ports, achieving multi-antenna transmission through MIMO technology. The transmitting device 100 transmits data signals to the receiving device 200 via a power line carrier MIMO channel. After receiving and detecting the signals, the receiving device 200 feeds back the channel status information to the transmitting device 100, forming a complete closed-loop communication system.

[0121] In embodiments of this application, the transmitting device 100 may include a transmitting end preprocessing module 110, which consists of an SVD decomposition unit 10, a power allocation unit 20, and a spatial mapping unit 30. The transmitting device 100 sequentially performs channel coding and constellation point mapping on the data payload bit stream to be transmitted to obtain modulation symbol data. The transmitting end preprocessing module 110 then performs spatial mapping preprocessing on the modulation symbol data. The processed signal is then modulated via orthogonal frequency division multiplexing and coupled to the power line through each antenna port for transmission.

[0122] In embodiments of this application, the receiving device 200 may include a receiving end post-processing module 210. After receiving the coupled signal from the power line, the receiving device 200 performs processing such as timing synchronization, cyclic prefix removal, and fast Fourier transform to obtain the frequency domain signal. Then, the receiving end post-processing module 210 uses the equivalent channel matrix to perform data detection and demodulation on the received signal to recover the transmitted data. At the same time, the receiving device 200 feeds back the channel state information to the transmitting device 100.

[0123] In some embodiments, the transmitting device 100 and the receiving device 200 employ a cooperative adaptation working mode. The receiving device 200 obtains the channel state information of the power line carrier MIMO channel through channel estimation and feeds it back to the transmitting device 100 in a periodic or aperiodic manner via the power line carrier communication link. Based on the feedback channel state information, the transmitting device 100 performs singular value decomposition on the channel matrix by the SVD decomposition unit 10, determines the power allocation matrix by the power allocation unit 20, and generates a precoding matrix by the spatial mapping unit 30 and performs spatial mapping processing on the modulation symbol data. The post-processing parameters of the receiving device 200 are linked with the precoding parameters of the transmitting device 100 in real time. The transmitting device 100 dynamically allocates transmission resources according to the channel characteristics and port characteristics of the three-wire power line structure, and the receiving device 200 adjusts the post-processing mode accordingly, forming a closed-loop adaptation of preprocessing-transmission-postprocessing.

[0124] In some embodiments, the system supports three transmission modes: single-input single-output, antenna diversity, and spatial multiplexing. The system can select the appropriate transmission mode based on the actual conditions of the current power line carrier MIMO channel. When channel fading is severe and high transmission reliability is required, antenna diversity mode is selected to obtain diversity gain; when channel conditions are good and high data throughput is required, spatial multiplexing mode is selected to obtain multiplexing gain to improve the transmission rate.

[0125] The embodiments of this application utilize the collaborative operation of the transmitting device 100 and the receiving device 200. Based on the channel state information fed back from the receiving end, preprocessing is performed at the transmitting end and post-processing is performed at the receiving end to form a closed-loop communication system adapted to the characteristics of the power line carrier MIMO channel. This system can track dynamic changes in the channel and adjust transmission parameters in real time, making full use of the channel capacity and improving the transmission efficiency and reliability of the three-phase power line carrier communication system.

[0126] The operation of the transmitting device 100 for three-phase power line carrier communication according to the present application will be described below with reference to specific embodiments.

[0127] The sending end performs spatial mapping matrix processing.

[0128] SVD decomposition: Modes 0 to 6 are single streams, without precoding, and therefore no SVD decomposition is performed. The corresponding output for this step is:

[0129] The channel matrices for modes 7 to 12 are decomposed using the SVD method. Modes 7 to 9 correspond to 3-antenna transmissions, and the channel matrix is ​​represented by all 3 columns. Modes 10 to 12 correspond to 2-antenna transmissions, and the channel matrix is ​​represented by the corresponding 2 columns for each mode. The output matrix after SVD decomposition is a unitary matrix. The sequence numbers of each mode correspond to those in Table 2. The subscripts are consistent.

[0130] Power distribution can be configured in different ways.

[0131] Method 1: Default power allocation.

[0132] If the default power allocation is used, the space mapping matrix is ​​left-multiplied by the power allocation matrix. Normalize. For an identity matrix with normalization coefficients, power normalization is performed. The coefficients can be calculated by the norm of the space mapping matrix. Sure.

[0133] Mode 0, Mode 7, Mode 8, Mode 9:

[0134] Mode 1, Mode 2, Mode 3:

[0135] Mode 4, Mode 5, Mode 6:

[0136] Mode 10, Mode 11, Mode 12:

[0137] Method 2: Perform two-stream transmission power balancing for modes 7 to 9.

[0138] Power balancing is performed based on the default power allocation in Method 1.

[0139] There are a total of 10 modes, including modes 0 to 6 and modes 10 to 12. Same as method one.

[0140] For patterns 7 to 9, a total of 3 patterns, the matrix... Simultaneously, power normalization and two-stream power balancing are performed. The output matrix is: Mode 7:

[0141] Mode 8:

[0142] Pattern 9:

[0143] The spatial mapping matrix after normalization and power balancing is shown in Table 2 below: Table 2 Spatial Mapping Matrix

[0144] In the second step of power allocation in the implementation of this application, in addition to the conventional default power allocation method 1 and average power allocation method 2, power reversal method 3 and water injection algorithm method 4 can also be used as supplements or replacements.

[0145] Transmitting device 100 multiplies the transmitted signal by a precoding matrix Preprocessing is performed. If necessary, a water-filling algorithm for power allocation is also completed in this section. These processes achieve stream-to-space mapping. The transmitted signal is then mapped to the transmit port. Data from each transmit port is IFFTed and then transmitted. Correspondingly, the receiver 200 performs post-processing on the received signal.

[0146] In summary, the transmitting device 100, receiving device 200, and system 1000 for three-phase power line carrier communication according to the embodiments of this application include at least the following innovative points: (1) The transmitting end preprocessing and the receiving end postprocessing constitute a system suitable for power line carrier MIMO communication. In a power line carrier MIMO communication system consisting of transmitting-end preprocessing and receiving-end postprocessing, the transmitting-end preprocessing module includes a precoding unit that maps data from the source to the stream and from the stream to the antenna port. The receiving-end postprocessing module maps the receiving antenna to the stream, providing input for subsequent data demodulation. The transmitting-end preprocessing and receiving-end postprocessing employ a collaborative adaptation mechanism. The transmitting end dynamically allocates transmission resources based on the channel characteristics and port features of the three-wire power line structure. The receiving-end postprocessing parameters and the transmitting-end precoding parameters are linked in real time, forming a closed-loop adaptation of preprocessing, transmission, and postprocessing.

[0147] The implementation method of this application differs from related technologies that directly migrate wireless MIMO systems to power line communication without considering the adaptability of power line channel transmission characteristics to MIMO technology, and suffer from the shortcomings of independent design of the transmitting and receiving ends and lack of collaborative optimization. The implementation method of this application fully utilizes the physical advantages of the three-wire power line structure and solves the technical problems of low transmission efficiency or poor transmission reliability caused by factors such as unbalanced attenuation, high channel correlation, dynamic time-varying, and severe noise interference in power line carrier MIMO systems.

[0148] (2) Transmitting device 100 with preprocessing module The transmitting end comprises an SVD decomposition unit 10, a power allocation unit 20, and a spatial mapping unit 30, forming a transmitting end preprocessing module 110. The transmitting end preprocessing module 110 constructs a precoding matrix based on the spatial correlation characteristics of the power line carrier MIMO channel and introduces singular value decomposition and power allocation algorithms to optimize the current three-phase power line carrier MIMO communication technology. The transmitting device 100 of this embodiment can dynamically adjust the precoding matrix weights based on real-time detection feedback of power line MIMO channel transmission loss, attenuation, coupling interference, noise, and interference intensity, and combines various feasible power allocation strategies to achieve the effect of transmitting signals adapting to complex time-varying MIMO channels. The transmitting device 100 of this embodiment overcomes the shortcomings of current technology with fixed antenna selection and no power allocation design, requiring no additional hardware overhead and improving channel capacity and transmission reliability.

[0149] (3) Receiving device 200 with post-processing module The receiver has a receiver post-processing module 210, which matches the transmitter pre-processing module 110. The receiver post-processing module 210 performs post-processing on the channel transfer function based on dynamic channel state information. The channel obtained through the receiver post-processing module 210 can be used for subsequent detection, demodulation, and decoding. Through the receiver post-processing module 210, the power line carrier MIMO channel can be fully utilized, improving transmission efficiency and performance.

[0150] (4) Systems with feedback function A power line carrier MIMO communication system with feedback capability is disclosed. The feedback function is achieved by the receiver feeding back the channel transfer function and noise characteristic parameters to the transmitter. These parameters are communicated to the transmitter via a feedback path, and the feedback period can be dynamically adjusted according to the time-varying characteristics of the power line channel. The transmitter updates the precoding matrix and power allocation strategy in real time based on the feedback information. Unlike current technologies that lack a feedback mechanism and therefore cannot adapt to the time-varying characteristics of power line channels, this application's implementation achieves dynamic optimization of system performance through the linkage of feedback information with transmitter preprocessing and receiver postprocessing, thus adapting to power line MIMO communication scenarios in complex time-varying channel environments.

[0151] The transmitting device 100, receiving device 200, and system 1000 of this application, applicable to three-phase power line carrier communication, are suitable for power line carrier MIMO transmission. They can be applied to complex MIMO channel environments, fully leveraging the advantages of MIMO technology and solving the technical problems currently existing in three-phase power line carrier communication. The technical advantages include at least the following aspects: (1) Improve transmission reliability in power line carrier MIMO loss and attenuation environments. The combination of three phases creates complexity and differences in signal attenuation between power line carrier MIMO antennas. Current technology does not consider this attenuation imbalance, and the use of antenna ports is mainly reflected in simple port selection and fixed power allocation. This approach is not suitable for scenarios where multiple spatial streams experience different fading, as it does not handle the differences in arrival signal power between spatial streams, which may cause the receiver to fail to detect data correctly.

[0152] The embodiments of this application allocate power, and the power allocation methods include, but are not limited to: default allocation, balanced allocation so that the power of the two streams is equal, and allocation based on SVD output. Matrix power flipping and the water-filling theorem are used to allocate high power to high-quality channels. These methods achieve power balancing or adjustment, effectively offsetting channel attenuation and reducing the bit error rate of the demodulated data at the receiver.

[0153] (2) Make full use of channel capacity to improve transmission efficiency Current technical solutions do not consider the correlation of MIMO channels, thus failing to fully leverage the core advantages of MIMO technology and achieve the effect of increasing channel capacity through multi-antenna multiplexing. In a multi-antenna link, if the transmitter knows the channel state information, it can multiply the signal by a matrix precoding matrix to concentrate energy on the strong modes of the channel while suppressing weak interference / noise modes; the receiver only needs simple processing to recover the data. By precoding, beamforming and interference suppression are completed at the transmitter in advance, thereby improving the signal-to-interference-plus-noise ratio (SINR) or reducing the bit error rate. In the embodiments of this application, the transmitter employs an SVD decomposition unit 10, a power allocation unit 20, and a spatial mapping unit 30, while the receiver employs a receiver post-processing module 210, which together constitute a pre-processing-post-processing system. The transmitter knows the CSI and uses singular value decomposition to preprocess the transmitted signal and post-process the received signal, making the received signal equivalent to a synthesis of multiple equivalent virtual SISO channel signals. The MIMO channel capacity is equal to the sum of the capacities of each virtual SISO channel. By comparing the equivalent virtual SISO channel capacity, different modulation orders can be selected or configured for use, improving detection performance or spectral efficiency. Furthermore, by using power allocation algorithms that satisfy total power constraints, such as the water-filling principle, more power can be allocated to channels with higher signal-to-noise ratios (SNR), thereby maximizing channel capacity.

[0154] (3) Time-varying tracking channel Due to the power frequency characteristics of the power system and the dynamic changes in electrical load, the characteristics of power line carrier MIMO channels exhibit significant time-varying properties. Current technical solutions do not track or adapt to the time-varying nature of MIMO channels. The transmitting end preprocessing apparatus in this application relies on channel state information fed back from the receiving end, which reflects the dynamic changes of the channel. Therefore, the preprocessing performed at the transmitting end and the postprocessing performed at the receiving end can use a precoding matrix that matches the current channel to ensure the detection of transmitted data. The channel state information feedback mode can be configured as periodic or aperiodic feedback to match the actual application scenarios of power line carrier communication.

[0155] (4) Noise and interference resistance Current technical solutions cannot suppress interference / noise by allocating power through preprocessing at the transmitting end and postprocessing at the receiving end. The implementation method of this application supports power allocation, concentrating energy in the channel space with a high signal-to-interference-plus-noise ratio, thereby improving error rate performance and ensuring correct data detection in complex noise and interference environments.

[0156] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0157] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the function involved, as will be understood by those skilled in the art to which embodiments of this application pertain.

[0158] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable storage medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, a computer-readable storage medium can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable storage medium could be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0159] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0160] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it includes one or a combination of the steps of the method embodiments. Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc.

[0161] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A transmitting device suitable for three-phase power line carrier communication, characterized in that, The system includes a preprocessing module for the transmitting end, which comprises: The SVD decomposition unit is used to perform singular value decomposition on the channel matrix to obtain a unitary matrix, wherein the channel matrix originates from the channel state information of power line carrier MIMO fed back by the receiving device. The power allocation unit is used to determine the power allocation matrix according to the preset power allocation criteria. The spatial mapping unit is used to generate a precoding matrix based on the unitary matrix and the power allocation matrix, and to perform spatial mapping processing on the modulation symbol data to be transmitted using the precoding matrix before outputting it to the antenna port.

2. The transmitting device according to claim 1, characterized in that, The singular value decomposition is represented as: in, The channel matrix; and All are unitary matrices; It is a diagonal matrix whose diagonal elements are singular values ​​of H; the unitary matrix output by the SVD decomposition unit is .

3. The transmitting device according to claim 1, characterized in that, The preset power allocation criteria include at least one of the following: default power allocation criteria, power balance allocation criteria, power reversal allocation criteria, and water injection algorithm allocation criteria; For the default power allocation criterion, the power allocation matrix is ​​used to keep the power ratio between each antenna port constant; For the power balance allocation criterion, the power allocation matrix is ​​used to make the transmission power of each spatial stream equal; For the power inversion allocation criterion, the power allocation matrix is ​​used to allocate power according to the inverse ratio of the gain of each spatial stream channel, so that the energy of each spatial stream signal reaching the receiving device is equal; For the water-filling algorithm allocation criterion, the power allocation matrix is ​​used to allocate power to each spatial flow according to the water-filling theorem under the total power constraint, so as to maximize the channel capacity.

4. The transmitting device according to claim 1, characterized in that, The spatial mapping unit is used to left-multiply the antenna selection matrix by the power allocation matrix, and then left-multiply by the unitary matrix to obtain the precoding matrix.

5. The transmitting device according to claim 1, characterized in that, The channel matrix is ​​fed back to the transmitting device by the receiving device in a periodic or non-periodic manner, and the transmitting end preprocessing module updates the precoding matrix in real time according to the fed-back channel matrix.

6. The transmitting device according to claim 1, characterized in that, The transmitting device supports multiple spatial mapping modes, including: In single-port mode, one antenna port in the three-phase power line conductor combination is selected for single-stream transmission. Two-port antenna diversity mode selects two antenna ports for single-stream diversity transmission; Three-port antenna diversity mode selects three antenna ports for single-stream diversity transmission; Two-port spatial multiplexing mode: Select two antenna ports for two-stream spatial multiplexing transmission; Three-port spatial multiplexing mode selects three antenna ports for two-stream spatial multiplexing transmission.

7. The transmitting device according to claim 1, characterized in that, The spatial mapping unit is used to left-multiply the modulation symbol data by the precoding matrix to obtain the transmission signal, and output the transmission signal to each antenna port.

8. A receiving device suitable for three-phase power line carrier communication, characterized in that, Includes a receiver post-processing module, the receiver post-processing module being used for: Multiplying the channel matrix on the right by the precoding matrix generated in the transmitting device according to any one of claims 1-7 yields an equivalent channel matrix; The received signal is detected and demodulated using the equivalent channel matrix to recover the transmitted data; Based on the power line carrier MIMO method, channel state information is fed back to the transmitting device.

9. The receiving device according to claim 8, characterized in that, The channel state information includes the channel transfer function and noise characteristic parameters, and the channel transfer function is used to construct the channel matrix.

10. A system suitable for three-phase power line carrier communication, characterized in that, include: The transmitting device according to any one of claims 1-7; and The receiving device according to claim 8 or 9, wherein the transmitting device and the receiving device transmit signals based on power line carrier MIMO.

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