Short code coding structure and embedded confidential transmission method using same

Abstract

The invention discloses a short code coding structure and an embedded secrecy transmission method using the same, which are applied to the field of wireless coding and decoding technology and automatic control, and the method comprises the following steps: taking a preset number of equal-width high and low level pulses as initial segments, connecting wide and high level pulses of 2ms-8ms, and then connecting an identification code, an address code, a data code and a verification code in sequence; for the judgment of the signals' 0 'and' 1 ', the specific steps are as follows: appointing 1 high and n low as the signal' 0 ', appointing n high and 1 low as the signal' 1 ', and determining the data as non-effective data under other conditions; wherein the value of n is as follows: when the code length is required to be higher than a preset threshold value, n is equal to 2, and when the code length is required to be lower than the preset threshold value, n is greater than 2. According to the invention, better confidential transmission is realized, the power consumption is reduced, the bit error rate is reduced, the low-power requirement of small equipment is met, and the CPU overhead and the system power consumption cost are reduced.

Description

Technical Field

[0001] The invention relates to the field of wireless coding and decoding technology and automatic control, and in particular to a short code coding structure and a hybrid confidentiality transmission method using the structure. Background Art

[0002] At present, wireless control equipment is very popular at home and abroad, and the frequency bands used are also very rich. Common civilian bands include 315M, 433M, 2.4G, etc. The encoding and decoding scheme of remote control is very mature, which brings the advantage of easy chip integration and information copying, thereby greatly reducing costs. The disadvantage is that a "key" can be copied by reading the original remote control data, and its potential risks are obvious. Some illegal personnel can obtain remote control signals through technical means and carry out theft. In order to achieve the security and confidentiality of wireless remote control, some anti-copying technologies such as rolling codes are also increasingly used, but they can still be cracked. Some encoding and decoding schemes using encryption algorithms have achieved remarkable results, but the number of coding bits is significantly lengthened, the transmission efficiency is reduced, and the power consumption is increased. Therefore, how to better achieve confidential transmission, reduce power consumption, and reduce bit error rate has always been an urgent problem to be solved.

[0003] RFID systems usually use one of the following coding methods: non-return-to-zero (NRZ) coding, Manchester coding, unipolar HZ coding, differential bi-phase (DBP) coding, Miller coding, and differential coding. In layman's terms, different pulse signals are used to represent 0 and 1. Among them, non-return-to-zero code is easy to generate long high and long low levels, such as Figure 1 As shown in the figure, it is inefficient and prone to bit errors and zero-level interference, and it is impossible to extract synchronization signals, so it has been rarely used. In Manchester coding, the value of a bit is represented by the change in level (up / down) during half a bit period within the length of the bit. A negative jump during half a bit period represents a binary "1", and a positive jump during half a bit period represents a binary "0". The level change within half a bit period is used to distinguish, and no long high level or long low level will be generated. Figure 2As shown in the figure, Manchester coding is usually used for data transmission from electronic tags to readers when load modulation or backscatter modulation of the carrier wave is used, because this is conducive to detecting data transmission errors. This is because the "no change" state is not allowed within the bit length. When the data bits sent by multiple electronic tags at the same time have different values, the received rising and falling edges cancel each other out, resulting in an uninterrupted subcarrier signal within the entire bit length. Since this state is not allowed, the reader can use this error to determine the specific location where the collision occurred, but if the decoding end uses the level discrimination mode, it may cause bit errors. Other coding methods also determine the "0" and "1" signals based on the length of the high and low levels or the change of the edge within the cycle, each with different advantages and disadvantages.

[0004] In addition, the wireless channel environment is harsh and unpredictable. Radio wave transmission not only has propagation path loss, but is also affected by unfavorable factors such as multipath effect, Doppler frequency shift and shadow effect, which greatly affects the communication quality. Channel coding technology has experienced decades of development, from the early Hamming code, BCH code, RS code, to the later convolutional code, cascade code, and today's Turbo code and LDPC code. The distance between the performance that can be achieved and the Shannon limit is constantly shrinking. These advanced channel coding technologies have been widely used in the field of communications.

[0005] RS code is Reed-Solomon code, which is an error-correcting code that can correct multiple errors. The RS code is (204, 188, t=8), where t is the number of bytes that can be resistant to the length, corresponding to 188 symbols, and the supervision segment is 16 bytes (overhead byte segment). In practice, the RS encoding of (255, 239, t=8) is implemented, that is, 51 all-0 bytes are added before 204 bytes (including synchronization bytes), and the first 51 empty bytes are discarded after the RS code is generated to form a truncated (204, 188) RS code. The coding efficiency of RS is: 188 / 204. Typical applications include CDs, VCDs, etc.

[0006] Turbo code, also known as parallel cascade convolutional code, cleverly combines convolutional code and random interleaver to realize the idea of ​​random coding. Turbo code adopts a simple convolutional code cascade structure and maximum a posteriori probability iterative decoding algorithm to achieve error correction decoding performance close to the Shannon limit. An important feature of Turbo code is that its component code adopts recursive systematic convolutional code, which is also an important reason for its superior performance. Turbo code technology has been widely used, and many of its key technologies have been improved to make its performance higher and more conducive to the implementation of software and hardware. Turbo code has been used as the standard for deep space communication in the United States, and has also been identified as one of the channel coding schemes for the third generation mobile communication system (IMT-2000). For example, 3GPP's WCDMA, CDMA2000 and China's TD-SCDMA all use Turbo channel coding schemes.

[0007] However, although these coding technologies have advanced error correction and anti-interference capabilities, and their advanced modulation and coding technologies can achieve high-capacity and high-speed communications, their complex algorithms require the sender and receiver to have CPUs with high-speed computing capabilities and big data processing performance to reduce latency, while high power consumption and high costs are unavoidable. In fact, for miniaturized devices, the amount of data that needs to be encoded and decoded is very small, so for miniaturized devices, how to improve encoding and decoding efficiency, reduce CPU overhead and reduce system power consumption is the most important.

[0008] To this end, how to provide a short code encoding structure and a chimeric confidential transmission method using the structure to address the problem of information leakage in current wireless transmission, which is easy to be reversely decoded and deciphered, to achieve better confidential transmission, reduce power consumption, reduce bit error rate, and meet the low power requirements of small devices, reduce CPU overhead and system power consumption costs is an urgent problem that technicians in this field need to solve. Summary of the invention

[0009] In view of this, the present invention proposes a short code encoding structure and a hybrid secure transmission method using the structure.

[0010] In order to achieve the above object, the present invention adopts the following technical solution:

[0011] A short code encoding structure, comprising:

[0012] A preset number of high and low level pulses of equal width are used as the starting segment, and a high and low level pulse of width of 2ms-8ms is connected. The identification code, address code, data code and check code are connected in sequence after the high and high level pulses;

[0013] The discrimination of "0" and "1" signals is as follows:

[0014] The identification code, address code, data code and check code use 1 high and n low as the signal "0", and n high and 1 low as the signal "1". Other cases are considered as invalid data.

[0015] Among them, the high-level duty ratio of 1 high and n low is 1 / n+1; the high-level duty ratio of n high and 1 low is n / n+1;

[0016] The value of n is as follows:

[0017] When the code length requirement is higher than the preset threshold, n=2, and when the code length requirement is lower than the preset threshold, n>2, and n is an integer.

[0018] Optionally, for the discrimination of "0" and "1" signals, a variable duty cycle technology is also included, as follows:

[0019] The identification code adopts n=a, specifically: the identification code agrees that 1 high and a low are signaled as "0", and a high and 1 low are signaled as "1";

[0020] The address code, data code and check code use n=b, specifically: the address code, data code and check code use 1 high and b low as the signal "0", and b high and 1 low as the signal "1";

[0021] All other cases are deemed as invalid data.

[0022] The present invention also provides a chimeric confidentiality transmission method using a short code encoding structure, comprising:

[0023] Based on the short code encoding structure, the data is divided into more than two blocks of subcodes through the guidance of more than two groups of different identification codes, and sent in series through one or more transmitters. The receiving end combines the subcodes according to the agreed identification code order and decodes them to obtain the complete data after transmission.

[0024] Optionally, when one or more transmitters transmit subcodes in series, each subcode segment is separated by a preset time length.

[0025] It can be seen from the above technical solutions that, compared with the prior art, the present invention proposes a short code encoding structure and a chimeric confidential transmission method using the structure. The present invention adopts a short code encoding method of descrambling code-identification code-address code-data code-check code, and based on this, performs chimeric confidential transmission of data, thereby achieving better confidential transmission, reducing power consumption, reducing bit error rate, and meeting the low power requirements of small devices, reducing CPU overhead and system power consumption costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the NRZ encoding method in the prior art.

[0028] Figure 2 This is a schematic diagram of the Manchester encoding method in the prior art.

[0029] Figure 3 It is a schematic diagram of the waveform of the short code encoding structure with n=2 of the present invention.

[0030] Figure 4 This is a schematic diagram of the encoding waveform of the chip PT2262 in the prior art.

[0031] Figure 5 It is a schematic diagram of the waveform of the variable duty cycle short code encoding structure of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Embodiment 1:

[0034] Embodiment 1 of the present invention discloses a short code encoding structure, such as Figure 3 As shown, including:

[0035] A preset number of high and low level pulses of equal width are used as the starting segment, i.e., the descrambling code, and a high and low level pulse of width of 2ms-8ms is connected. The identification code, address code, data code and check code are connected in sequence after the high and high level pulses.

[0036] The commonly used 2262 and 2272 hardware codec chips have solved the zero-level interference and initial garbled code problems better, because "0", "1" and "f" are all high level plus low level, and they are distinguished by different duty cycles, such as Figure 4As shown, there will be no long high level and long low level. Four groups of data are transmitted repeatedly each time to prevent interference. The reason is that the first group of word codes is easily interfered with. The receiving end is considered valid only when two groups of exactly the same address code and data code are received at the same time. It can be seen that the high and low levels are three times the relationship ( Figure 4 4a and 12a), of course, a 4a high level plus a 128a low level is required between each code word as a synchronization header. The present invention adopts an efficient encoding method, which can greatly reduce the power consumption and time of a single transmission. Several high and low level pulses with equal width are used at the beginning to eliminate the garbled code of the receiving module. Although the high and low level pulses with a width of 2ms-8ms reduce the efficiency, it is easy to identify effective data and eliminate interference signals. The microprocessor only considers that the data is effective when it recognizes the effective width, which greatly improves the anti-interference ability of the wireless product and reduces the bit error rate.

[0037] The discrimination of "0" and "1" signals is as follows:

[0038] The identification code, address code, data code and check code stipulate that 1 high and n low are signaled as "0", and n high and 1 low are signaled as "1". All other cases are deemed as invalid data.

[0039] Among them, the high-level duty cycle of 1 high and n low is 1 / n+1; the high-level duty cycle of n high and 1 low is n / n+1.

[0040] The value of n is as follows:

[0041] Here n is a positive integer; as n increases, the fault tolerance to adverse conditions such as frequency drift and temperature drift will be better, but the short code duration will increase.

[0042] Therefore, when the code length requirement is higher than the preset threshold, n=2 (such as Figure 3 As shown in the figure, for a group of 25 data bits, this discrimination scheme does not use a synchronization check code, but adopts a simple equal-interval level judgment scheme. In the absence of strong interference, its bit error rate does not exceed 1 / 2 25 ; When the code length requirement is lower than the preset threshold (when the code length requirement is not high), n>2, and n is an integer, the discrimination scheme further improves reliability.

[0043] For the discrimination of "0" and "1" signals, a variable duty cycle technology is also included to further improve confidentiality, such as Figure 5 As shown below:

[0044] The identification code adopts n=a, specifically: the identification code agrees that 1 high and a low are signaled as "0", and a high and 1 low are signaled as "1";

[0045] The address code, data code and check code use n=b, specifically: the address code, data code and check code use 1 high and b low as the signal "0", and b high and 1 low as the signal "1";

[0046] All other cases are deemed as invalid data.

[0047] When decoding, different code segments can be decoded according to the agreed variable duty cycle.

[0048] Practice has proved that the coding method of the present invention only needs to send one set of codes each time, without repeating several times, to decode well. Due to the use of a short code structure, the check code uses the inverse code of the data code instead of using parity check, the purpose is to ensure the reliability of the data without repeating the code; even if a receiving module with a stray wave output (such as a super regeneration module) is used, the sensitivity and reliability will not be reduced. The newly encoded 2ms-8ms wide high-level pulse ensures the reliability and convenience of subsequent decoding. The reason why a wide pulse greater than 10ms is not used is that the transmission efficiency of some transmitting modules will be significantly reduced in a wider high-level mode, and the distance will become closer, so the new coding method is more versatile.

[0049] The coding structure of the present invention adopts the method of descrambling code-identification code-address code-data code-check code, so that effective decoding can be achieved by transmitting a code word, which greatly improves the transmission efficiency. Whether the receiving end adopts super regeneration or super heterodyne, satisfactory results can be obtained. For the battery-powered receiving end, low power consumption applications are often required. The short code mode of the present invention realizes low power consumption of the receiving end, and adopts the following method: the receiving end periodically turns on the receiving module, and determines whether to enter the receiving state through the width and height level. If there is no 2-8ms width and height level, it re-enters the dormant standby state. If a 2-8ms high level is received, it maintains the awake state and continues to receive signals. For example, if the signal is sent once for 50ms, the receiving end adopts the method of opening for 100ms and closing for 1s. The transmitting end needs to send 22 signals (i.e., 1.1s) continuously each time, so that at least one complete signal falls into the receiving end in the open state, thereby achieving decoding. Since the receiving end is in module shutdown for 9 / 10 of the time, if the current of the receiving module is 5mA when working, the average current is reduced to 0.5mA in this mode, and the power consumption is reduced by 10 times. By adjusting the power-on duty cycle, lower power consumption can be achieved.

[0050] Embodiment 2:

[0051] Embodiment 2 of the present invention discloses a chimeric confidentiality transmission method using a short code encoding structure, including:

[0052] Based on the short code encoding structure, the data is divided into more than two sub-codes through the guidance of more than two groups of different identification codes (the address code is the same), and sent in series through one or more transmitters. The receiving end combines the sub-codes according to the agreed identification code order and decodes them to obtain the complete data after transmission.

[0053] Different from the default "0101" address start code, the present invention compiles the identification code according to the agreed rules as the address with special meaning recognized by the receiving end, and sorts the groups of subcodes with the same address of different identification codes according to the agreed rules, so as to embed them into a complete data code. This type of identification code with more than 2 groups can achieve higher confidentiality, just like multiple keys can open a lock. Even if the decryptor obtains the full data information of all subcodes through various means, it still cannot be decoded due to the lack of combination rules, which effectively improves data security. In theory, the larger the number of combinations, the higher the security level, but it also increases the CPU overhead and reduces the data transmission efficiency.

[0054] At the same time, when one or more transmitters send short codes in series, each short code is separated by a preset time (such as several seconds), so that some readers think that the code transmission has ended, thereby preventing theft.

[0055] Embodiment 3:

[0056] Embodiment 3 of the present invention discloses a specific application of a short code encoding structure in Embodiment 1, as follows:

[0057] In the automatic tracking headlamp products, there is a wireless single-pedal technology, which is characterized by using a switch to achieve multiple functions such as up, down, turning on and off the light, and changing the brightness. The implementation principle of the single-pedal technology is: tap to turn on the light, change the light, and turn off the light. Each tap changes once, and the cycle continues. The single-pedal technology is mainly implemented by the CPU to determine the delay time of the pedal, thereby transmitting data with the same address code but different data codes, and the decoding end implements different functions according to different data codes. Its low power consumption characteristics benefit from the short code encoding technology of the present invention, so that the wireless pedal can use a button lithium battery for a long time, and the antenna uses a PCB antenna, which greatly reduces the weight and size.

[0058] At present, the coding and decoding technology has made great progress. It can not only identify the occurrence of bit errors, but also correct them. This is extremely important for the transmission of important information. In order to achieve long distance, the sensitivity of the receiving end is getting higher and higher, some exceeding -120dBm. High sensitivity also brings a large number of interference pulses. The modulation method of digital signals also affects the signal quality of the output end. Amplitude shift keying (ASK), frequency shift keying (FSK) and phase shift keying (PSK) are usually used. In terms of frequency band utilization and anti-noise performance (or power utilization), PSK is the most superior. For big data and high-speed transmission, due to limited frequency band resources, more complex modulation and coding technologies such as single-carrier frequency domain equalization and orthogonal frequency division multiplexing (OFDM) are used. Both use block transmission and cyclic prefix structures, and use FFT / I FFT (fast Fourier transform / inverse fast Fourier transform) for signal processing. It makes the most of limited spectrum resources, can achieve high-speed wireless transmission, and improve the system transmission capacity and performance. However, not all wireless devices need to use the most advanced coding technology, because with the improvement of coding and decoding performance, its software and hardware have higher requirements, which not only involves cost, but also power consumption and volume, which runs counter to the pursuit of lighter and smaller medical headlights. The automatic tracking headlight adopts a simple ASK modulation method, and only adopts reverse code error checking without error correction. The short code structure of descrambling code-identification code-address code-data code-check code in the present invention is adopted. Each headlight uses a different address code. This extremely concise new coding method, although a low-end CPU and 4M main frequency are used in actual use, still shows excellent control performance. At the same time, the structure is light and the power consumption is extremely low, and a good clinical use effect is achieved.

[0059] The embodiment of the present invention discloses a short code encoding structure and a chimeric confidentiality transmission method using the structure. The present invention adopts a short code encoding method of descrambling code-identification code-address code-data code-check code, and based on this, performs chimeric confidentiality transmission of data, thereby achieving better confidentiality transmission, reducing power consumption, reducing bit error rate, meeting the low power requirements of small devices, and reducing CPU overhead and system power consumption costs.

[0060] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0061] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A short code encoding structure, characterized in that: include: A preset number of high and low level pulses of equal width are used as the starting segment, and a high and low level pulse of width of 2ms-8ms is connected, and the high and high level pulses are sequentially connected with an identification code, an address code, a data code and a check code; The discrimination of "0" and "1" signals is as follows: The identification code, address code, data code and check code are defined as 1 high and n low as signal "0", n high and 1 low as signal "1", and other cases are considered as invalid data; Among them, the high level duty ratio of 1 high and n low is 1 / n+1; the high level duty ratio of n high and 1 low is n / n+1; The value of n is as follows: When the code length requirement is higher than the preset threshold, n=2, and when the code length requirement is lower than the preset threshold, n>2, and n is an integer.

2. A short code encoding structure according to claim 1, characterized in that: For the discrimination of "0" and "1" signals, a variable duty cycle technology is also included, as follows: The identification code adopts n=a, specifically: the identification code stipulates that 1 high and a low are signaled as "0", and a high and 1 low are signaled as "1"; The address code, data code and check code adopt n=b, specifically: the address code, data code and check code agree that 1 high and b low are signal "0", and b high and 1 low are signal "1"; All other cases are deemed as invalid data.

3. A method for mosaic secure transmission using a short code encoding structure according to any one of claims 1 to 2, characterized in that: include: Based on the short code encoding structure, the data is divided into more than two blocks of subcodes through the guidance of more than two groups of different identification codes, and sent in series through one or more transmitters. The receiving end combines the subcodes according to the agreed identification code order and decodes to obtain the complete data after transmission.

4. A chimeric confidentiality transmission method according to claim 3, characterized in that: When the one or more transmitters transmit subcodes in series, each subcode segment is separated by a preset time length.

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