CN102932109A - Timing synchronization and spreading factor detection system and method for power line communication - Google Patents
Timing synchronization and spreading factor detection system and method for power line communication Download PDFInfo
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- CN102932109A CN102932109A CN201210470471XA CN201210470471A CN102932109A CN 102932109 A CN102932109 A CN 102932109A CN 201210470471X A CN201210470471X A CN 201210470471XA CN 201210470471 A CN201210470471 A CN 201210470471A CN 102932109 A CN102932109 A CN 102932109A
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Abstract
The invention discloses a timing synchronization and spreading factor detection system and a timing synchronization and spreading factor detection method for power line communication. The timing synchronization and spreading factor detection system comprises a plurality of synchronous detectors and a selector logic, wherein the synchronous detectors are used for receiving a data frame; the selector logic is connected with an output of the synchronous detectors; each synchronous detector comprises a first stage of correlator and a second stage of correlator connected with an output of the first stage of correlator; and the data frame comprises synchronization words, control words, training words and frame effective data which are positioned at an initial position. According to the invention, synchronous codes have very good autocorrelation and cross-correlation properties, so that a receiver can obtain accurate timing information and well distinguish different synchronization words; and the synchronous codes have a layered structure, so that a detection circuit at the receiving end can be greatly simplified.
Description
Technical field
The present invention relates to a kind of Timing Synchronization and spreading factor detection system and method thereof of power line communication.
Background technology
In Remote Power-Meter Reading System, carrier chip is by interfaces such as RS232 or RS484, and the data of reading power meters are loaded into power line tens with Data Modulation to send to the carrier frequency of hundreds of KHz and by coupler; The integrated reading device of receiving terminal receives the data that reach hundreds of ammeters, and is sent to electric administrative department by telephone wire or with wireless mode.In the integrated reading device of receiving terminal, after band pass filter will have the carrier wave of signal to separate from power line, carrier chip carried out demodulation to signal and restores original data.The carrier of communication is ready-made power line, need not again to lay communication line as 485 checking meter.Also not resembling needs the wireless transmission complicated sending and receiving devices to come transmission information.It need not to set up extra communication line, does not also take valuable radio spectrum resources, is the optimal selection that is used for remote centralized meter-reading system of generally acknowledging.
And in traditional data communication system, have the frame structure that utilizes the HDLC agreement to be used for power line communication, this frame structure is specific as follows:
| Flag sequence | Address field | Control field | Information field | The frame check field | Flag sequence |
According to HDLC agreement regulation, all communications must begin with a flag sequence, and with same EOS.This flag sequence is 01111110, claims flag sequence.Consist of a complete information unit between from the opening flag to the end mark, be called a frame.All information is to transmit with the form of frame, and tab character provides the border of each frame.Receiving terminal can be found out by search " 01111110 " beginning and the end of frame, sets up frame synchronization with this.After flag sequence, an address field (8 or many bits) and a control field (8 or 16 bit) can be arranged.Address field is used for stipulating the address of the receiving station that communicates by letter with it.Control field can be stipulated several orders.Follow is information field (length can be 0 or 8 integral multiple) after control field.Information field includes the data that will transmit.Frame check field (16 or 32 bit) is used for frame is carried out cyclic redundancy check (CRC), the sequence of its verification scope from the 1st bit of address field to last bit of information field.
Therefore for ease of the detection of synchronization character, the length of synchronization character is fixed.This causes in the high s/n ratio situation, and the length of synchronization character may surpass the correct demand that detects, and has reduced data transmission efficiency.In the low signal-to-noise ratio situation, synchronization character might not obtain enough protections again, causes the synchronization character that detects that receiver can not be correct.
Summary of the invention
The Timing Synchronization and spreading factor detection system and the method thereof that the purpose of this invention is to provide a kind of power line communication.
For achieving the above object, the present invention adopts the first technical scheme: a kind of Timing Synchronization of power line communication and spreading factor detection system, it comprises: several synchronizing indicators and a selector logic that links to each other with the output of described synchronizing indicator of being used for receiving data frames, and synchronizing indicator comprises the second level correlator that first order correlator links to each other with output with first order correlator, and wherein Frame comprises and is positioned at initial synchronization character, control word, train word and frame valid data.
Described synchronization character adopts hierarchical structure to construct:
A=[a
0?a
1?a
2?…?a
15]
B=[b
0?b
1?b
2?…?b
k-1]
Wherein A is outer code, and length is 16; B is ISN, and k is the length of B sequence, and overall code equals
The expression Kronecker product, each a, b value+1 or-1.
Described control word comprises frame type and frame length information at least, and the frame valid data then comprise source address, destination address, ammeter data, check digit information at least.
For achieving the above object, the present invention adopts the second technical scheme: a kind of Timing Synchronization of power line communication and spreading factor detection method is characterized in that:
Make up Frame, it comprises at least and is positioned at initial synchronization character, control word, train word and frame valid data, and wherein synchronization character has 2 kinds of different lengths at least, with the different spreading factor of correspondence;
Quality according to channel is selected different spreading factors, and Direct-Spread sends for control word, train word and frame valid data after the synchronization character and by transmitter;
Receiver detects original position and the kind of data-frame sync word simultaneously, by original position, obtains Timing Synchronization information; By the synchronization character kind, obtain spreading factor;
Receiver demodulation control word, train word and frame valid data.
Preferably, the present invention further comprises for several synchronizing indicators of receiving data frames and a selector logic that links to each other with the output of described synchronizing indicator, and synchronizing indicator comprises the second level correlator that first order correlator links to each other with output with first order correlator.
Preferably, described synchronization character adopts hierarchical structure to construct:
A=[a
0?a
1?a
2?…?a
15]
B=[b
0?b
1?b
2?…?b
k-1]
Wherein A is outer code, and length is 16; B is ISN, and k is the length of B sequence, and overall code equals
The expression Kronecker product, each a, b value+1 or-1.
Preferably, described control word comprises frame type and frame length at least, and the frame valid data then comprise source address, destination address, ammeter data, check digit information at least.
Advantage of the present invention is:
Synchronous code among the present invention has particularly preferred auto-correlation and their cross correlation, so that receiver can obtain accurate timing information and distinguish preferably different synchronization characters, and synchronous code has hierarchy, and the testing circuit of receiving terminal can be simplified greatly.
Description of drawings
The invention will be further described below in conjunction with drawings and Examples:
Fig. 1 is the structural representation of combined detector among the present invention.
Fig. 2 is the circuit diagram of synchronizing code detector among the present invention.
Fig. 3 is that spreading factor of the present invention=1 synchronization length is the autocorrelation performance figure of 128 synchronous code.
Fig. 4 is that spreading factor of the present invention=1 synchronization length is that 128 synchronous code and spreading factor=2 synchronization length are the cross-correlation performance figure between 256 the synchronous code.
Embodiment
Embodiment: shown in Fig. 1-4, the invention provides a kind of Timing Synchronization of power line communication and the embodiment of spreading factor detection method, wherein Frame comprises and is positioned at initial synchronization character, control word, train word and frame valid data, and form is as follows:
| Synchronization character | Control word | Train word | The frame valid data |
Synchronization character be used for to receive brings in the beginning that detects Frame, and control word comprises some key parameters of Frame, frame type for example, frame length etc.Train word is used for channel estimating.The frame valid data then comprise the information such as source address, destination address, ammeter data, check digit, and wherein spreading factor can obtain when detecting synchronization character, and namely each synchronization character is corresponding to a spreading factor.
Be the noise that overcomes channel and the impact of decline, Frame (except synchronization character) is used the Direct-Spread technology, be receive data successfully in receiving terminal one side, detect simultaneously original position and the kind of data-frame sync word.By original position, obtain Timing Synchronization information; By the synchronization character kind, obtain spreading factor;
Only obtain Timing Synchronization information and spreading factor, receiver just can demodulation control word and frame valid data.
Spreading factor is based on channel quality and selects.In the situation that high signal noise ratio (SNR), spreading factor can be 2^N, and in the situation that the low signal-to-noise ratio channel, and spreading factor is that to select be 2^ (N+1), 2^ (N+2) or 2^ (N+M).In electric line communication system of the present invention, suppose N=0, M=3, in the situation that high signal noise ratio (SNR), spreading factor can be 1, namely the frame valid data is not used spread spectrum.And in the situation that the lowest signal-to-noise channel, spreading factor can be 8, this means that per 8 sampled signals represent an information symbol.Bottom is still with N=0, and the example of M=3 illustrates the specific embodiment of this patent, but the value of N and M can be selected different value according to the needs of real system.
In electric line communication system of the present invention, the length of synchronization character is different.Have four kinds of synchronization character A/B/C/D(to be equivalent to spreading factor 1/2/4/8) length be respectively 2^K, 2^ (K+1), 2^ (K+2), 2^ (K+M) bit.And in electric line communication system of the present invention K=7.At transmitting terminal, transmitter can be according to default, the order that receives, or select different spreading factors according to the quality of channel, thus select different synchronization characters.Basically there is the dual mode transmitting terminal can know the quality of channel: 1) to be the quality according to when spreading factor deduction of the noise transmitting channel of the Frame that receives.2) be if sent the response that packet does not obtain the other side last time, then transmitting terminal is considered to increase transmitting power or select larger spreading factor.
In order to reduce the hardware complexity of receiver, synchronization character adopts hierarchical structure, synchronization character structure minute two stages:
A=[a
0?a
1?a
2?…?a
15]
B=[b
0?b
1?b
2?…?b
k-1]
Wherein A is outer code, and length is 16; B is ISN, and k is the B(ISN) length of sequence.Overall code equals
Kronecker is long-pending for the expression Kronecker.Each a, b value+1 or-1.The A(outer code) length of sequence always 16.The B(ISN) length depends on spreading factor, and this spreading factor is based on channel quality and selects.This synchronization character is selected by computer search.The below is some examples:
If spreading factor=1, then synchronization length is 128 sample:
A0=[-1?-1?-1?-1?1?1?-1?-1?-1?-1?1?-1?1?-1?1?-1];
B0=[1?1?-1?1?-1?1?-1?1];
If spreading factor=2, then synchronization length is 256 sample:
A1:[1?-1?1?1?-1?1?1?1?-1?1?-1?-1?-1?1?1?1]
B1:[1?-1?-1?-1?1?-1?1?1?-1?1?1?1?1?-1?1?1]
If spreading factor=4, then synchronization length is 512 sample:
A2:[1?1?1?-1?-1?-1?1?-1?-1?-1?-1?1?-1?-1?1?-1]
B2:[1?1?1?-1?-1?-1?1?-1?1?1?1?-1?1?1?-1?1?1?1?1?-1?-1?-1?1?-1?-1?-1?-1?1?-1-1?1?-1]
If spreading factor=8, then synchronization length is 1024 sample:
A3:[-1?1?1?1?1?-1?1?1?-1?1?1?1?-1?1?-1?-1]
B3:[1?1?-1?1?1?1?1-1?1?1-1?1-1-1-1?1?1?1-1?1?1?1?1-1-1-1?1-1?1?1?1-1?1-1-1-1-11-1-1-1?1?1?1-1?1-1-1?1-1-1?1-1-1-1?1-1-1?1?1?1?1-1?1]
As shown in Figure 1, in electric line communication system of the present invention, the detection that is used for spreading factor and synchronization character is to realize by a combined detector, and it is comprised of 4 synchronizing indicators and a selector logic.The signal that receives is at first sampled, and then digitlization carries out pre-treatment step.And pre-treatment step comprises: remove direct current offset, digital Auto Gain control, again sampling, signal filtering.Pretreated signal then is transfused to 4 parallel synchronizing indicators.If useful signal of any synchronizing indicator output is arranged, then frame timing, synchronization character and spreading factor can be determined.If there are a plurality of synchronizing indicators all to export useful signal, the synchronizing indicator of the peak value of then output maximum is determined frame regularly and spreading factor.
In Fig. 2, synchronizing indicator comprises the second level correlator (i.e. outer code correlator) that first order correlator (namely in code correlator) links to each other with output with first order correlator.The complex valued signals of first order correlator output is input at once second level correlator and carries out computing.The complex valued signals of second level correlator output is used to power calculation, thereby compares with predefined threshold value (thresholding i).If the power of correlator output is greater than threshold value, effectively the performance number of signal and the time that is detected thereof are sent to the selector logic.First order correlator and second level correlator are equipped with timer D and adder.Code element of each timer D inhibit signal.If obtain the time Estimate accuracy of 1/2 code element, delay unit D stores 2 data from the sample survey.If obtain the time Estimate accuracy of 1/4 code element, delay unit D stores 4 data from the sample survey.Delay unit can be realized with hardware register or internal memory.Because power communication system of the present invention adopts the QPSK modulation technique, each word comprises homophase and samples mutually with quadrature.The value of each data from the sample survey represents input signal by a plurality of bits, to guarantee the accuracy of digital signal.It is 128 correlator for length.First order correlator has 128 timer D and 16 adders, and second level correlator has 15 timer D and 16 adders.256, the dependency structure of the synchronization character of 512,1024 length is similar.For example, 1024 length correlators, first order correlator and the total adder of second level correlator are 64+16=80.The internal memory of the first order correlator in 4 synchroprobes, namely delay unit can be shared.
The symbol lengths of synchronization character of the present invention, consist of fully different from data, synchronization character detects at frame, timing extraction, the effect that the aspects such as frequency and gain control have particular importance, help to improve systematic function, synchronization character can adopt computer search to produce simultaneously, have particularly preferred auto-correlation and their cross correlation, as shown in Figure 3 and Figure 4, autocorrelation performance is so that receiver can obtain accurate timing information, their cross correlation is so that receiver can be distinguished different synchronization characters preferably, and then demodulation spreading factor, and synchronous code has hierarchy, so that the testing circuit of receiving terminal can be simplified greatly.
Certainly above-described embodiment only is explanation technical conceive of the present invention and characteristics, and its purpose is to allow the people who is familiar with technique can understand content of the present invention and according to this enforcement, can not limit protection scope of the present invention with this.The all Spirit Essence of main technical schemes is done according to the present invention equivalent transformation or modification all should be encompassed within protection scope of the present invention.
Claims (7)
1. the Timing Synchronization of a power line communication and spreading factor detection system, it is characterized in that it comprises: several synchronizing indicators and a selector logic that links to each other with the output of described synchronizing indicator of being used for receiving data frames, and synchronizing indicator comprises the second level correlator that first order correlator links to each other with output with first order correlator, wherein Frame comprises and is positioned at initial synchronization character, control word, train word and frame valid data, and wherein sync word length is variable.
2. the Timing Synchronization of a kind of power line communication according to claim 1 and spreading factor detection system is characterized in that: described synchronization character adopts hierarchical structure to construct:
A=[a
0?a
1?a
2?…?a
15]
B=[b
0?b
1?b
2?…?b
k-1]
Wherein A is outer code, and length is 16; B is ISN, and k is the length of B sequence, and overall code equals
The expression Kronecker product, each a, b value+1 or-1.
3. the Timing Synchronization of a kind of power line communication according to claim 1 and 2 and spreading factor detection system, it is characterized in that: described control word comprises frame type and frame length at least, and the frame valid data then comprise source address, destination address, ammeter data, check digit information at least.
4. the Timing Synchronization of a power line communication and spreading factor detection method is characterized in that it may further comprise the steps:
Make up Frame, it comprises at least and is positioned at initial synchronization character, control word, train word and frame valid data, and wherein synchronization character has 2 kinds of different lengths at least, with the different spreading factor of correspondence;
Quality according to channel is selected different spreading factors, and Direct-Spread sends for control word, train word and frame valid data after the synchronization character and by transmitter;
Receiver detects original position and the kind of data-frame sync word simultaneously, by original position, obtains Timing Synchronization information; By the synchronization character kind, obtain spreading factor;
Receiver demodulation control word, train word and frame valid data.
5. the Timing Synchronization of a kind of power line communication according to claim 4 and spreading factor detection method, it is characterized in that it comprises: be used for several synchronizing indicators and a selector logic that links to each other with the output of described synchronizing indicator of receiving data frames, and synchronizing indicator comprises the second level correlator that first order correlator links to each other with output with first order correlator.
6. the Timing Synchronization of a kind of power line communication according to claim 5 and spreading factor detection method is characterized in that: described synchronization character adopts hierarchical structure to construct:
A=[a
0?a
1?a
2?…?a
15]
B=[b
0?b
1?b
2?…?b
k-1]
Wherein A is outer code, and length is 16; B is ISN, and k is the length of B sequence, and overall code equals
The expression Kronecker product, each a, b value+1 or-1.
7. according to claim 4 or the Timing Synchronization of 5 or 6 described a kind of power line communications and spreading factor detection method, it is characterized in that: described control word comprises frame type and frame length information at least, and the frame valid data then comprise source address, destination address, ammeter data, check digit information at least.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103414494A (en) * | 2013-07-25 | 2013-11-27 | 深圳市力合微电子有限公司 | Signal frame generation method of power-line carrier communication system |
| CN106297250A (en) * | 2016-10-10 | 2017-01-04 | 普天智能照明研究院有限公司 | A kind of remote family data acquisition system and energy consumption acquisition system |
| CN113179359A (en) * | 2021-04-21 | 2021-07-27 | 中国科学院长春光学精密机械与物理研究所 | Serial image data training system based on synchronous words |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100157907A1 (en) * | 2007-10-31 | 2010-06-24 | Qualcomm Incorporated | Method and apparatus for signaling transmission characteristics in a wireless communication network |
| CN101267418B (en) * | 2007-03-13 | 2012-03-21 | 华为技术有限公司 | Method, device and system for sending and receiving communication system parameters |
| CN102739339A (en) * | 2011-04-01 | 2012-10-17 | 杭州讯能科技有限公司 | Power line carrier communication method and system thereof |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101267418B (en) * | 2007-03-13 | 2012-03-21 | 华为技术有限公司 | Method, device and system for sending and receiving communication system parameters |
| US20100157907A1 (en) * | 2007-10-31 | 2010-06-24 | Qualcomm Incorporated | Method and apparatus for signaling transmission characteristics in a wireless communication network |
| CN102739339A (en) * | 2011-04-01 | 2012-10-17 | 杭州讯能科技有限公司 | Power line carrier communication method and system thereof |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103414494A (en) * | 2013-07-25 | 2013-11-27 | 深圳市力合微电子有限公司 | Signal frame generation method of power-line carrier communication system |
| CN103414494B (en) * | 2013-07-25 | 2015-05-20 | 深圳市力合微电子股份有限公司 | Signal frame generation method of power-line carrier communication system |
| CN106297250A (en) * | 2016-10-10 | 2017-01-04 | 普天智能照明研究院有限公司 | A kind of remote family data acquisition system and energy consumption acquisition system |
| CN113179359A (en) * | 2021-04-21 | 2021-07-27 | 中国科学院长春光学精密机械与物理研究所 | Serial image data training system based on synchronous words |
| CN113179359B (en) * | 2021-04-21 | 2022-03-01 | 中国科学院长春光学精密机械与物理研究所 | Serial image data training system based on synchronous words |
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