Leader structure for MIMO broadband power line communication and generation method

Abstract

The invention relates to the technical field of power line communication (PLC), in particular to a leading structure for MIMO broadband power line communication and a generation method. The preamble structure comprises preambles of three sending channels, and each of the preambles of the three sending channels comprises a basic symbol unit SYNCP and an anti-congruent symbol unit SYNCM with the phase opposite to that of the basic symbol unit SYNCP. The method is characterized in that the preamble of the sending channel comprises a front half part and a rear half part, and the basic symbol units SYNCP and the anti-congruent symbol units SYNCM of the front half part of the preamble of the sending channel are sequentially arranged at intervals in a staggered mode. The structure not only supports communication between MIMO PLC devices, but also keeps backward compatibility with previous state grid HPLC devices.

Description

Technical Field

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

[0002] With the continuous development of smart grid applications, higher requirements are placed on the efficiency and reliability of power line communication systems. MIMO PLC is a promising technology that 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 initial reception tasks of the receiver, such as frame detection, symbol timing, channel estimation, and automatic gain control (AGC).

[0003] In practical applications, power systems usually use three-phase lines for power transmission, and such transmission lines are often connected to a large number of single-phase and three-phase devices. Therefore, when building 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 can support the hybrid communication mode of single-input single-output SISO and multiple-input multiple-output MIMO, so that the receiver can automatically identify whether the transmitter is a single-transmitter device or a multi-transmitter device, so as to facilitate subsequent signal processing such as channel estimation, and the new device can be compatible with the previous version of the 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 a generation method for MIMO broadband power line communication, which structure not only supports communication between MIMO PLC devices, but also maintains backward compatibility with previous State Grid HPLC equipment.

[0005] In order 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 comprises preambles of three transmission channels, and the preambles of the three transmission channels all comprise a basic symbol unit SYNCP and an inverted symbol unit SYNCM having a phase opposite to that of the basic symbol unit SYNCP. It is characterized in that the preambles of the transmission channels all comprise a first half and a second half, and the basic symbol unit SYNCP and the inverted symbol unit SYNCM of the first half of the preamble of the transmission channel are arranged in an interlaced interval in sequence.

[0007] In the above scheme, the structure of the SYNCP and SYNCM intervals allows the receiving device to determine whether the sending device is multi-transmitting or single-transmitting when doing local correlation, thereby achieving backward compatibility with existing SISO PLC devices.

[0008] The basic symbol unit SYNCP and the inverted symbol unit SYNCM of the second half of the transmission channel are both arranged in at least two consecutive arrangements.

[0009] In the above scheme, at least two consecutively arranged basic symbol units SYNCP and inverted symbol units SYNCM can not only successfully complete the necessary number of symbols required for MIMO channel estimation, but also sufficient guard interval is conducive to eliminating the interference between leading symbols of channel estimation.

[0010] Among the three transmission channels, the preamble of the first transmission channel is not subjected to time domain cyclic shift CS, the preamble of the second transmission channel is subjected to time domain cyclic shift CS of one time interval, and the preamble of the third transmission channel is subjected to time domain cyclic shift CS of another time interval.

[0011] In the above scheme, after the channel merging, the second half of the leading signal will not be superimposed and offset, resulting in large fluctuations in the signal, ensuring that the time domain power is relatively stable before and after. This is beneficial to AGC locking and thus also beneficial to the estimation of the channel function.

[0012] The leading edge of the sending channel starts from the second half of 0.5 inverted symbol unit SYNCM.

[0013] The preamble of the first transmission channel ends with the first half of 0.5 basic symbol unit SYNCP, the preamble of the second transmission channel ends with the first half of 0.5 inversion symbol unit SYNCM, and the preamble of the third transmission channel ends with the first half of 0.5 0.5 basic symbol unit SYNCP.

[0014] The characteristic of the generation method of the above-mentioned preamble structure is that the basic symbol unit SYNCP is converted from the frequency domain signal into a time domain symbol, and then the basic symbol unit SYNCP is reversed to obtain the inverted symbol unit SYNCM, and then the preamble of the second transmission channel and the preamble of the third transmission channel are cyclically shifted at different time domain intervals.

[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] Wherein, C is the available carrier set, and N is 1024.

[0018] The above solution has the following advantages:

[0019] Since the preamble of the transmission channel of the preamble structure for MIMO broadband power line communication of the present invention contains the first half and the second half, the basic symbol unit SYNCP and the inverted symbol unit SYNCM of the first half of the preamble of the transmission channel are arranged in sequence with staggered intervals. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the existing SISO preamble structure.

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

[0022] Figure 3 It is a schematic diagram of the cyclic shift operation of the preambles of the second and third sending channels at different time domain intervals in the embodiment. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with 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 leader structure of the State Grid HPLC protocol standard.

[0025] like Figure 2 As shown, the preamble structure for MIMO broadband power line communication of this embodiment includes preambles of three transmission channels, and the preambles of the three transmission channels all contain a basic symbol unit SYNCP and an inverted symbol unit SYNCM with a phase opposite to the basic symbol unit SYNCP. The preambles of the transmission channels all contain a first half and a second half, and the basic symbol unit SYNCP and the inverted symbol unit SYNCM of the first half of the preamble of the transmission channel are arranged in sequence with staggered intervals. The structure of SYNCP and SYNCM intervals is adopted so that the receiving device can judge whether the transmitting device is multi-transmitting or single-transmitting when performing local correlation, thereby achieving backward compatibility with existing SISO PLC devices.

[0026] like Figure 2 As shown, in this embodiment, the basic symbol unit SYNCP and the inverted symbol unit SYNCM of the second half of the leading edge of the transmission channel are arranged in at least two consecutive arrangements. At least two consecutive arrangements of the basic symbol unit SYNCP and the inverted symbol unit SYNCM can not only smoothly complete the necessary number of symbols required for MIMO channel estimation, but also the sufficient protection interval is conducive to eliminating the interference between leading symbols of channel estimation.

[0027] Among the three transmission channels, the preamble of the first transmission channel does not have a time domain cyclic shift CS, the preamble of the second transmission channel has a time domain cyclic shift CS of a time interval, and the preamble of the third transmission channel has a time domain cyclic shift CS of another time interval. After channel merging, the second half of the preamble will not be superimposed and offset to cause a large fluctuation in the signal, ensuring that the time domain power is relatively stable. This is conducive to AGC locking, and thus also conducive to the estimation of the channel function.

[0028] like Figure 2 As shown, in this embodiment, the leading end of the transmission channel is the second half of 0.5 inverted symbol unit SYNCM. The leading end of the first transmission channel is the first half of 0.5 basic symbol unit SYNCP, the leading end of the second transmission channel is the first half of 0.5 inverted symbol unit SYNCM, and the leading end of the third transmission channel is the first half of 0.5 0.5 basic symbol unit SYNCP.

[0029] like Figure 2As shown, specifically, the preambles of the first transmission channel, the second transmission channel and the third transmission channel contain 12 symbol units, the first transmission channel is channel 0, the second transmission channel is channel 1, and the third transmission channel is channel 2. For the convenience of distinction, the symbol unit of each transmission channel ends with the corresponding conduction number, such as the symbol unit SYNCP of the first transmission channel is SYNCP0. The beginning of the preamble of the first transmission channel is the second half SYNCM0 of 0.5 inverted symbol units SYNCM, followed by the 0th symbol unit SYNCP0, the 1st symbol unit SYNCM0, and so on, until the 5th symbol unit is SYNCM0, which constitutes the first half of the preamble of the first transmission channel, and then, the 6th, 7th, 8th, 9th and 10th symbol units are all SYNCP0, and the preamble of the first transmission channel finally constitutes the first half of the 0.5 basic symbol unit SYNCP0, and the 6th, 7th, 8th, 9th, 10th symbol units and the preamble of the first transmission channel finally constitute the second half of the preamble of the first transmission channel. The beginning of the preamble of the second transmission channel is the second half SYNCM1 of 0.5 inverted symbol units SYNCM, followed by the 0th symbol unit SYNCP1, the 1st symbol unit SYNCM1, and so on, the 5th symbol unit is SYNCM1, constituting the first half of the preamble of the second transmission channel, and then, the 6th and 7th symbol units are SYNCP1, the 8th, 9th and 10th symbol units are SYNCM1, and the preamble of the second transmission channel finally consists of the first half of 0.5 basic symbol units SYNCM1, and the 6th, 7th, 8th, 9th, 10th symbol units and the preamble of the first transmission channel finally constitute the second half of the preamble of the second transmission channel. The beginning of the preamble of the third transmission channel is the second half SYNCM2 of 0.5 inverted symbol units SYNCM, followed by the 0th symbol unit SYNCP2, the 1st symbol unit SYNCM2, and so on, the 5th symbol unit is SYNCM2, constituting the first half of the preamble of the third transmission channel, and then, 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 finally consists of the first half of 0.5 basic symbol units SYNCP2, and the 6th, 7th, 8th, 9th, 10th symbol units and the preamble of the third transmission channel finally constitute the second half of the preamble of the first transmission channel.

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

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

[0032]

[0033] Wherein, C is the available carrier set, and N is 1024.

[0034] The basic symbol unit SYNCP is then inverted to obtain the inverted symbol unit SYNCM.

[0035] like Figure 3 As shown, a cyclic shift operation with different time domain intervals is performed on the preamble of the second transmission channel and the preamble of the third transmission channel.

[0036] In this embodiment, the MIMO preamble reference phase complies with the State Grid HPLC protocol standard.

[0037] The preamble structure for MIMO broadband power line communication of the present invention is different from SISO, which has 10.5 consecutive SYNCPs in front. The first half of the preamble of the present invention adopts a structure with SYNCP and SYNCM intervals, so that the receiving device can judge whether the transmitting device is multi-transmitting or single-transmitting when doing local correlation. At the same time, the second half of the present invention adopts at least two continuous symbols, which can not only smoothly complete the necessary number of symbols required for MIMO channel estimation, but also the sufficient protection interval is conducive to eliminating the interference between the preamble symbols of channel estimation. At the same time, the preamble of the first transmission channel of MIMO is not subjected to time domain cyclic shift CS, the preamble of the second transmission channel is a time domain cyclic shift CS of a time interval, and the preamble of the third transmission channel is a time domain cyclic shift CS of another time interval. After the channel is merged, the second half of the preamble will not be superimposed and offset to cause a large fluctuation of the signal, ensuring that the time domain power is relatively stable before and after. It is conducive to AGC locking, and thus also conducive to the estimation of the channel function.

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

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

Claims

1. A preamble structure for MIMO broadband power line communication, comprising preambles of three transmission channels, wherein the preambles of the three transmission channels each comprise a basic symbol unit SYNCP and an inverted symbol unit SYNCM having a phase opposite to that of the basic symbol unit SYNCP; characterized in that: The preamble of the transmission channel includes a first half and a second half, and the basic symbol unit SYNCP and the inverted symbol unit SYNCM of the first half of the preamble of the transmission channel are arranged in sequence with staggered intervals.

2. The preamble structure for MIMO broadband power line communication according to claim 1, characterized in that: The basic symbol unit SYNCP and the inverted symbol unit SYNCM of the second half of the transmission channel are arranged in at least two consecutive arrangements.

3. The preamble structure for MIMO broadband power line communication according to claim 2, characterized in that: Among the three transmission channels, the preamble of the first transmission channel is not subjected to time domain cyclic shift CS, the preamble of the second transmission channel is subjected to time domain cyclic shift CS of one time interval, and the preamble of the third transmission channel is subjected to time domain cyclic shift CS of another time interval.

4. The preamble structure for MIMO broadband power line communication according to claim 3, characterized in that: The leading edge of the sending channel starts from the second half of 0.5 inverted symbol unit SYNCM.

5. The preamble structure for MIMO broadband power line communication according to claim 4, characterized in that: The preamble of the first transmission channel ends with the first half of 0.5 basic symbol unit SYNCP, the preamble of the second transmission channel ends with the first half of 0.5 inversion symbol unit SYNCM, and the preamble of the third transmission channel ends with the first half of 0.5 0.5 basic symbol unit SYNCP.

6. The method for generating a preamble structure for MIMO broadband power line communication according to claim 5, characterized in that: The basic symbol unit SYNCP is converted from a frequency domain signal into a time domain symbol, and then the basic symbol unit SYNCP is reversed to obtain an inverted symbol unit SYNCM, and then a cyclic shift operation with different time domain intervals is performed on the preamble of the second transmission channel and the preamble of the third transmission channel.

7. The method for generating a preamble structure for MIMO broadband power line communication according to claim 6, characterized in that: 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 the available carrier set, and N is 1024.

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