Preamble structure and generation method for MIMO wideband power line communication

Abstract

The application relates to the technical field of power line communication (PLC), in particular to a preamble structure and a generation method for MIMO wideband power line communication. The preamble structure comprises three transmission channel preambles, each of the three transmission channel preambles comprises a basic symbol unit SYNCP and an inverse symbol unit SYNCM opposite in phase to the basic symbol unit SYNCP. The feature is that each of the transmission channel preambles comprises a first half and a second half, and the basic symbol unit SYNCP and the inverse symbol unit SYNCM in the first half of the transmission channel preamble are arranged in an alternating and interval mode. The structure not only supports the communication between MIMO PLC devices, but also maintains the backward compatibility with the previous State Grid HPLC device.

Description

Technical Field

[0001] This invention relates to the field of power line communication (PLC) technology, and in particular to a preamble structure and generation method for MIMO broadband power line communication. Background Technology

[0002] With the continuous development of smart grid applications, higher demands are being placed on the efficiency and reliability of power line communication systems. MIMO PLC, as a promising technology, can increase data rates and provide robustness to harsh power line communication environments. However, the implementation of MIMO PLC systems requires an efficient preamble structure to support the receiver's initial reception tasks, such as frame detection, symbol timing, channel estimation, and automatic gain control (AGC).

[0003] In practical applications, power systems typically use three-phase lines for power transmission, and these transmission lines often connect a large number of single-phase and three-phase devices. Therefore, when constructing a new generation of power line communication protocols, the mixed use of these devices must be fully considered. For the design of the preamble structure, it is necessary to ensure that it supports mixed communication modes such as single-input single-output (SISO) and multiple-input multiple-output (MIMO), allowing the receiver to automatically identify whether the transmitter is a single-transmitter or a multi-transmitter for subsequent signal processing such as channel estimation. Furthermore, the new equipment must be compatible with previous versions of State Grid HPLC equipment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a preamble structure and generation method for MIMO broadband power line communication. This structure not only supports communication between MIMO PLC devices, but also maintains backward compatibility with the previous State Grid HPLC equipment.

[0005] To solve the above problems, the following technical solutions are provided:

[0006] The preamble structure for MIMO broadband power line communication of the present invention includes preambles for three transmission channels. Each of the three transmission channels includes a basic symbol unit (SYNCP) and an inverting symbol unit (SYNCM) that is out of phase with the SYNCP. The characteristic feature is that each transmission channel preamble contains a first half and a second half, and the basic symbol unit (SYNCP) and the inverting symbol unit (SYNCM) in the first half of the transmission channel preamble are arranged alternately.

[0007] In the above scheme, the structure of the SYNCP and SYNCM intervals allows the receiving device to determine whether the transmitting device is transmitting multiple times or only once when performing local correlation, thereby achieving backward compatibility with existing SISO PLC devices.

[0008] In this transmission channel, the basic symbol unit SYNCP and the inverted symbol unit SYNCM in the latter half of the transmission channel are arranged in at least two consecutive positions.

[0009] In the above scheme, the arrangement of at least two consecutive basic symbol units (SYNCP) and inverted symbol units (SYNCM) not only enables the successful completion of the necessary number of symbols required for MIMO channel estimation, but also the sufficient guard interval helps to eliminate inter-preamble interference in channel estimation.

[0010] Of the three transmission channels, the first transmission channel does not have a time-domain cyclic shift (CS) in its preamble, the second transmission channel has a time-domain cyclic shift (CS) of one time interval, and the third transmission channel has a time-domain cyclic shift (CS) of another time interval.

[0011] In the above scheme, after channel combining, the latter half of the preamble will not experience superposition or cancellation, preventing significant signal fluctuations and ensuring relative stability of the time-domain power. This is beneficial for AGC locking, and consequently, for channel function estimation.

[0012] The preamble of each transmission channel begins with the latter half of 0.5 inverted symbol units (SYNCM).

[0013] The first transmission channel's preamble ends with the first half of SYNCP (0.5 basic symbol units), the second transmission channel's preamble ends with the first half of SYNCM (0.5 inverted symbol units), and the third transmission channel's preamble ends with the first half of SYNCP (0.5 basic symbol units).

[0014] The above-mentioned method for generating the preamble structure is characterized by converting the basic symbol unit SYNCP from a frequency domain signal into a time domain symbol, then inverting the basic symbol unit SYNCP to obtain the inverted symbol unit SYNCM, and then performing cyclic shift operations with different time domain intervals on the preambles of the second and third transmission channels.

[0015] The formula for converting the basic symbol unit SYNCP from a frequency domain signal to a time domain symbol is as follows:

[0016]

[0017] Where C is the set of available carriers, and N is 1024.

[0018] The above approach has the following advantages:

[0019] Since the preamble structure for MIMO broadband power line communication of the present invention has a front half and a back half in the transmission channel, the basic symbol unit SYNCP and the inverted symbol unit SYNCM in the front half of the transmission channel are arranged alternately. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the existing SISO leader structure.

[0021] Figure 2 This is a schematic diagram of the preamble structure for MIMO broadband power line communication of the present invention;

[0022] Figure 3 This is a schematic diagram of the cyclic shift operation with different time-domain intervals performed by the preambles of the second and third transmission channels in the embodiment. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0024] like Figure 1 As shown, the existing SISO leader structure contains 10.5 SYNCPs and 2.5 SYNCMs. The SISO leader structure conforms to the State Grid HPLC protocol standard leader structure.

[0025] like Figure 2 As shown, the preamble structure for MIMO broadband power line communication in this embodiment includes preambles for three transmission channels. Each preamble for all three transmission channels contains a basic symbol unit (SYNCP) and an inverted symbol unit (SYNCM) that is out of phase with the SYNCP. Each transmission channel preamble has a first half and a second half. The basic symbol unit (SYNCP) and the inverted symbol unit (SYNCM) in the first half of the transmission channel preamble are arranged alternately. This SYNCP and SYNCM alternation structure allows the receiving device to determine whether the transmitting device is transmitting multiple devices or only transmitting devices when performing local correlation, thus achieving backward compatibility with existing SISO PLC equipment.

[0026] like Figure 2 As shown in this embodiment, the basic symbol unit (SYNCP) and the inverting symbol unit (SYNCM) in the latter half of the preamble of the transmission channel are arranged in at least two consecutive positions. This arrangement of at least two consecutive SYNCP and SYNCM units not only ensures the successful completion of the necessary number of symbols for MIMO channel estimation, but also provides sufficient guard intervals to eliminate inter-symbol interference in the preamble for channel estimation.

[0027] In the three transmission channels, the preamble of the first transmission channel does not undergo time-domain cyclic shift (CS), the preamble of the second transmission channel is a time-domain cyclic shift of one time interval, and the preamble of the third transmission channel is a time-domain cyclic shift of another time interval. After channel combining, the latter half of the preamble will not experience superposition or cancellation, preventing significant signal fluctuations and ensuring relative stability of the time-domain power. This is beneficial for AGC locking and thus also for channel function estimation.

[0028] like Figure 2 As shown, in this embodiment, the preamble of each transmission channel begins with the latter half of 0.5 inverted symbol units (SYNCM). The preamble of the first transmission channel ends with the first half of 0.5 basic symbol units (SYNCP), the preamble of the second transmission channel ends with the first half of 0.5 inverted symbol units (SYNCM), and the preamble of the third transmission channel ends with the first half of 0.5 basic symbol units (SYNCP).

[0029] like Figure 2As shown, specifically, the preamble of the first, second, and third transmission channels contains 12 coincidence units. The first transmission channel is channel 0, the second is channel 1, and the third is channel 2. For easy distinction, the symbol unit of each transmission channel ends with the corresponding on / off number, such as SYNCP0 for the symbol unit SYNCP of the first transmission channel. The preamble of the first transmission channel begins with the latter half of 0.5 inverted symbol units SYNCM0, followed by SYNCP0 for the 0th symbol unit, SYNCM0 for the 1st symbol unit, and so on, until the 5th symbol unit is SYNCM0, forming the first half of the preamble of the first transmission channel. Then, the 6th, 7th, 8th, 9th, and 10th symbol units are all SYNCP0. The preamble of the first transmission channel ends with the first half of 0.5 basic symbol units SYNCP0. The 6th, 7th, 8th, 9th, and 10th symbol units, along with the preamble of the first transmission channel, form the latter half of the preamble of the first transmission channel. The preamble of the second transmission channel begins with the latter half of SYNCM1, consisting of 0.5 inverted symbol units. Then, the 0th symbol unit is SYNCP1, the 1st symbol unit is SYNCM1, and so on, until the 5th symbol unit is SYNCM1, forming the first half of the preamble of the second transmission channel. Next, the 6th and 7th symbol units are SYNCP1, and the 8th, 9th, and 10th symbol units are all SYNCM1. The preamble of the second transmission channel ends with the first half of 0.5 basic symbol units SYNCM1. The 6th, 7th, 8th, 9th, and 10th symbol units, together with the preamble of the first transmission channel, form the latter half of the preamble of the second transmission channel. The preamble of the third transmission channel begins with the latter half of SYNCM2, consisting of 0.5 inverted symbol units. Then, the 0th symbol unit is SYNCP2, the 1st symbol unit is SYNCM2, and so on, until the 5th symbol unit is SYNCM2, forming the first half of the preamble of the third transmission channel. Next, the 6th and 7th symbol units are SYNCP2, the 8th and 9th symbol units are both SYNCM2, and the 10th symbol unit is SYNCP2. The preamble of the third transmission channel ends with the first half of 0.5 basic symbol units SYNCP2. The 6th, 7th, 8th, 9th, and 10th symbol units and the preamble of the third transmission channel together form the latter half of the preamble of the first transmission channel.

[0030] The method for generating the preamble structure for MIMO broadband power line communication in this embodiment is as follows:

[0031] The basic symbol unit SYNCP is converted from a frequency domain signal to a time domain symbol using the following formula.

[0032]

[0033] Where C is the set of available carriers, and N is 1024.

[0034] Then, the basic symbol unit SYNCP is reversed to obtain the inverted symbol unit SYNCM.

[0035] like Figure 3 As shown, the preambles of the second and third transmission channels can be cyclically shifted at different time intervals.

[0036] In this embodiment, the leading reference phase of MIMO conforms to the State Grid HPLC protocol standard.

[0037] The preamble structure for MIMO broadband power line communication in this invention differs from SISO, which has 10.5 consecutive SYNCPs. The first half of the preamble in this invention uses a SYNCP and SYNCM interval structure, allowing the receiving device to determine whether the transmitting device is multi-transmitting or single-transmitting during local correlation. Simultaneously, the latter half of this invention uses at least two consecutive symbols, which not only ensures the necessary number of symbols for MIMO channel estimation but also provides sufficient guard intervals to eliminate inter-symbol interference in the preamble for channel estimation. Furthermore, the preamble of the first MIMO transmission channel does not use a time-domain cyclic shift (CS), the preamble of the second transmission channel uses a time-domain cyclic shift (CS) of one time interval, and the preamble of the third transmission channel uses a time-domain cyclic shift (CS) of another time interval. After channel combining, the latter half of the preamble avoids superposition and cancellation that could cause significant signal fluctuations, ensuring relative stability of the time-domain power. This is beneficial for AGC locking, and thus also for channel function estimation.

[0038] The MIMO preamble structure and its generation method of this invention improve the efficiency of initial reception tasks in MIMO PLC systems, such as frame detection, symbol timing, channel estimation, and AGC. By employing a SYNCP and SYNCM interval structure, this invention enables the receiving device to accurately determine the type of transmitting device (MIMO or SISO), thereby achieving backward compatibility with existing SISO PLC devices. The MIMO preamble structure of this invention also improves the communication performance and reliability of the MIMO PLC system by optimizing the arrangement and number of symbols.

[0039] In summary, this invention proposes a preamble structure and generation method for MIMO broadband power line communication. This method not only improves the communication efficiency and reliability of MIMO PLC systems, but also ensures backward compatibility with existing SISO PLC equipment, and has broad application prospects.

Claims

1. A method for generating a preamble structure for MIMO wideband power line communication, the preamble structure comprising three transmission channel preambles, each of the three transmission channel preambles comprising a basic symbol unit SYNCP and an inverted symbol unit SYNCM which is phase-inverted to the basic symbol unit SYNCP; characterized in that, The basic symbol unit SYNCP is converted from a frequency domain signal to a time domain symbol, and an inverse symbol unit SYNCM is obtained by inverting the basic symbol unit SYNCP; in the three sending channels, a preamble of a first sending channel is not time domain cyclic shifted CS, a preamble of a second sending channel is time domain cyclic shifted CS for an interval, and a preamble of a third sending channel is time domain cyclic shifted CS for another interval; the preambles of the sending channels each contain a first half and a second half, the basic symbol units SYNCP and the inverse symbol units SYNCM of the first half of the preamble of the sending channel are arranged in an alternating interval, and the basic symbol units SYNCP and the inverse symbol units SYNCM of the second half of the preamble of the sending channel are arranged in at least two continuous arrangements.

2. The method of claim 1, wherein the preamble structure for MIMO wideband power line communication is generated by, The preambles of the sending channels each start with a second half of 0.5 inverse symbol units SYNCM.

3. The method of claim 1, wherein the preamble structure for MIMO wideband power line communication is generated by, The preamble of the first sending channel ends with a first half of 0.5 basic symbol units SYNCP, the preamble of the second sending channel ends with a first half of 0.5 inverse symbol units SYNCM, and the preamble of the third sending channel ends with a first half of 0.5 basic symbol units SYNCP.

4. The method of claim 1, wherein the preamble structure for MIMO wideband power line communication is generated by, The formula for converting the basic symbol unit SYNCP from a frequency domain signal to a time domain symbol is as follows: Wherein, C is a set of available carriers, and N is 1024.

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