Data transmission method and system based on index modulation

Abstract

The invention provides a data transmission method and system based on index modulation, and the data transmission method can be applied to a transmitting end, and comprises the steps: segmenting transmission data, and obtaining an index bit set and a modulation bit set; performing Chirp modulation on the modulation bit set to generate a Chirp signal; mapping the index bit set based on a preset index carrier to generate an index sequence; generating a data sequence based on the Chirp signal and the index sequence; the data sequence is sent to a receiving end based on a preset index carrier, so that the receiving end obtains a matched filtering sequence based on the data sequence, and then the receiving end obtains an index bit data sequence and a modulation bit data sequence based on the matched filtering sequence, therefore, the receiving end can restore the transmission data based on the index bit data sequence and the modulation bit data sequence. According to the data transmission method provided by the invention, part of data is ingeniously mapped into the index sequence for transmission, so that the data volume of the transmitted data is reduced, and the data transmission efficiency of the CSS is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a data transmission method and system based on index modulation. Background Art

[0002] In the field of wireless communications for the Internet of Things, Chirp Spread Spectrum (CSS) is a commonly used modulation technology that is widely used in low-power wide area networks (LPWAN). Chirp spread spectrum modulation uses linear frequency modulation signals to expand the bandwidth of the signal by continuously changing the frequency during transmission, which makes it have good anti-interference and strong signal coverage capabilities in harsh wireless environments. Especially in long-distance and low-signal conditions, CSS can significantly improve the reliability of received signals.

[0003] However, the advantage of CSS lies in its robustness and coverage, not its data transmission rate. Since spread spectrum technology improves anti-interference by increasing bandwidth, the symbol time of a single transmission is longer, resulting in a relatively low data transmission rate of CSS under the same spectrum bandwidth. Many applications in the Internet of Things, such as environmental monitoring and smart meter reading, usually only need to transmit a small amount of data, which makes the low-rate CSS an acceptable choice in these scenarios. But when a higher transmission rate is required, the spread spectrum characteristics and long symbol time of CSS limit the data throughput.

[0004] Therefore, CSS performs poorly in IoT applications that require high-frequency data transmission (such as real-time video surveillance, industrial control, etc.), and the low transmission rate problem becomes its bottleneck in these fields. In order to meet the needs of different IoT applications, it is usually necessary to balance communication distance, power consumption and transmission rate, which makes CSS more suitable for long-distance, low-power, low-data-rate application scenarios, but not for applications with high throughput requirements. Summary of the invention

[0005] The present invention aims to provide a data transmission method and system based on index modulation to solve the above technical problems, divide the transmission data and map part of the data into an index sequence for transmission, so as to effectively improve the data transmission efficiency of CSS.

[0006] In order to solve the above technical problems, the present invention provides a data transmission method based on index modulation, which can be applied to a transmitting end and specifically comprises the following steps:

[0007] Segment the transmission data to obtain an index bit set and a modulation bit set;

[0008] Performing Chirp modulation on the modulation bit set to generate a Chirp signal;

[0009] Mapping the index bit set based on a preset index carrier to generate an index sequence;

[0010] Generate a data sequence based on the Chirp signal and the index sequence;

[0011] The data sequence is sent to the receiving end based on the preset index carrier, so that the receiving end obtains the matched filter sequence based on the data sequence, and then the receiving end obtains the index bit data sequence and the modulation bit data sequence based on the matched filter sequence, so that the receiving end restores the transmission data based on the index bit data sequence and the modulation bit data sequence.

[0012] In the above scheme, the transmission data is divided into an index bit set and a modulation bit set: wherein the modulation bit set is modulated into a Chirp signal that can be transmitted, and the index bit set is mapped to a preset index carrier as an index sequence sent as a Chirp signal, and then a data sequence that can be transmitted is generated according to the Chirp signal and the index sequence. The above process can effectively reduce the amount of transmitted data and improve the data transmission efficiency of CSS. When the receiving end receives the data sequence, it only needs to perform matched filtering on the data sequence to obtain a matched filter sequence. The matched filter sequence contains the information of the Chirp signal and the index sequence. Therefore, the index bit data sequence and the modulation bit data sequence can be restored through the matched filter sequence, and then the transmission data can be restored according to the index bit data sequence and the modulation bit data sequence, thereby completing the data transmission.

[0013] The above solution divides the transmission data and cleverly maps part of the data into an index sequence for transmission, which greatly reduces the amount of transmitted data and can effectively improve the data transmission efficiency of CSS.

[0014] Furthermore, the index bit set includes a plurality of index bits having a sequence; and the mapping of the index bits based on a preset index carrier to generate an index sequence includes:

[0015] Determining the number of carrier elements of the preset index carrier based on the number of modulation bits in the modulation bit set;

[0016] Get the vector element sequence based on the number of vector elements;

[0017] All the index bits are mapped one by one to corresponding carrier elements in the carrier element sequence in order, so as to generate an index sequence based on the carrier element sequence.

[0018] In the above scheme, there can be many types of index carriers, including time slot index and carrier index, etc. Different types of index carriers have different carrier elements. In order to ensure that all data in the modulation bit set can be transmitted, it is necessary to determine the number of carrier elements according to the number of modulation bits in the modulation bit set. For example, if a carrier element has two states, the carrier elements in different states can be simply represented as 0 and 1, that is, the carrier elements in two states can represent one modulation bit; therefore, if the number of modulation bits is 2, at least two carrier elements with two states are required. After determining the number of carrier elements, the carrier elements can be arranged in order to obtain a carrier element sequence, and the carrier elements in the carrier element sequence are not less than the number of index bits in the index bit set. Then, all index bits can be mapped one by one to the corresponding carrier elements in the carrier element sequence in order to generate an index sequence. For carrier elements in two states, one way to understand it is that the index bit assigns a value to each carrier element, and this value can represent the state of the carrier element.

[0019] It should be noted that the carrier element can also have three states. At this time, if the number of modulation bits is 3, it has eight cases, such as 000, 001, 010 and 011, which cannot be represented by one carrier element, but two carrier elements can represent nine cases, so only two carrier elements are needed to represent three modulation bits. Similarly, the carrier element can also have multiple states, as long as all index bits can be mapped one by one to the corresponding carrier elements in the carrier element sequence.

[0020] The above scheme uses the state combination of the carrier element sequence to characterize different numbers of index bits. After the subsequent data transmission process, the carrier element sequence can be analyzed by the different data transmission states, and then the corresponding index bit set can be estimated.

[0021] Further, generating a data sequence based on the Chirp signal and the index sequence includes:

[0022] The Chirp signal includes a plurality of sequential modulation bits;

[0023] Based on a preset transmission rule, a number of modulated bits on the Chirp signal are sequentially loaded onto an index sequence to generate a data sequence including a number of data elements.

[0024] In the above scheme, the preset transmission rule is used to determine the data carrying rule. Taking the carrier elements in two states as an example, or simply representing the carrier element states as 0 and 1, the preset transmission rule can be to carry every 0 or every 1, that is, a number of modulated bits on the Chirp signal will be carried to the 0 or 1 bit on the index sequence. Correspondingly, if it is carried every 0, then in the subsequent data transmission, only the carrier elements in the 0 state will carry the modulated bits and be transmitted to the receiving end, so as to realize the transmission of the modulated bits. And the receiving end only needs to restore the carrier element sequence according to the type of index carrier and the number of the carrier element, and then estimate the corresponding index bit set.

[0025] It should be noted that if the index carrier is a time slot index and its carrier element is a time slot, then if it is carried every 0, the time slot in the 0 state will carry the modulation bit, that is, the modulation bit will be sent in the time slot, and conversely, the time slot in the 1 state will not carry the modulation bit, that is, the modulation bit will not be sent in the time slot. It should be noted that the definition of the 0 state and the 1 state depends on the preset transmission rule, and it can also be set to carry every 1.

[0026] Further, the index sequence is a binary sequence; based on a preset transmission rule, a number of modulated bits on the Chirp signal are sequentially loaded onto the index sequence to generate a data sequence including a number of data elements, including:

[0027] The preset transmission rule includes a rule for carrying every 0 or a rule for carrying every 1;

[0028] Based on the every-0 carrying rule or the every-1 carrying rule, a number of modulated bits on the Chirp signal are sequentially carried onto carrier elements corresponding to the index sequence to generate a data sequence including a number of data elements.

[0029] Further, the data sequence is sent to the receiving end based on a preset index carrier, so that the receiving end obtains a matched filter sequence based on the data sequence, and then the receiving end obtains an index bit data sequence and a modulated bit data sequence based on the matched filter sequence, so that the receiving end restores the transmission data based on the index bit data sequence and the modulated bit data sequence, including:

[0030] The data sequence is sent to the receiving end based on the preset index carrier, so that the receiving end performs the following steps:

[0031] Perform matched filtering on each data element in the data sequence in order to obtain a matched filtering sequence; each element in the matched filtering sequence has a unique element number;

[0032] Sequentially and according to the size of the data values, a preset first number of data elements with large data values ​​in the matched filter sequence are obtained as a modulated bit data sequence; the first number is the number of modulation bits in the modulation bit set;

[0033] Obtaining the element number of each data element in the modulated bit data sequence to obtain an element number sequence;

[0034] Based on the element number sequence, obtain the carrier element number;

[0035] Obtaining an index bit data sequence based on a carrier element number;

[0036] The transmission data is restored based on the index bit data sequence and the modulation bit data sequence.

[0037] In the above scheme, by confirming the first preset number of data elements with large data values ​​as the modulated bit data sequence, it is possible to estimate which data elements contain the modulated bits, and thus the modulated bit data sequence can be obtained. Then, the transmission rule of the modulated bits can be determined by the type of the index carrier and the preset transmission rule, that is, the element number sequence can obtain the carrier element number, and then the index bit data sequence can be obtained, and finally the transmission data can be restored based on the index bit data sequence and the modulated bit data sequence.

[0038] The present invention also proposes a data transmission system based on index modulation, which can apply the above-mentioned data transmission method based on index modulation, and the system includes a transmitting end and a receiving end; wherein the transmitting end includes a bit segmentation module, a modulation module, an index generation module, a data generation module and a data sending module; the receiving end includes a data receiving module, a matched filtering module, a sequence acquisition module and a data restoration module; wherein:

[0039] The bit segmentation module is used to segment the transmission data to obtain the index bit set and the modulation bit set; the modulation module is used to perform Chirp modulation on the modulation bit set to generate a Chirp signal; the index generation module is used to map the index bit set based on a preset index carrier to generate an index sequence; the data generation module is used to generate a data sequence based on the Chirp signal and the index sequence; the data sending module is used to send the data sequence to the receiving end; the data receiving module is used to receive the data sequence; the matched filtering module is used to obtain the matched filtering sequence based on the data sequence; the sequence acquisition module is used to obtain the index bit data sequence and the modulation bit data sequence based on the matched filtering sequence; the data restoration module is used to restore the transmission data based on the index bit data sequence and the modulation bit data sequence.

[0040] The system architecture provided by the above scheme is simple and has strong applicability. It can directly implement a data transmission method based on index modulation, dividing the transmission data into an index bit set and a modulation bit set: wherein the modulation bit set is modulated into a Chirp signal that can be transmitted, and the index bit set is mapped to a preset index carrier as an index sequence sent as a Chirp signal, and then a data sequence that can be transmitted is generated according to the Chirp signal and the index sequence. The above process can effectively reduce the amount of transmitted data and improve the data transmission efficiency of CSS. When the receiving end receives the data sequence, it only needs to perform matched filtering on the data sequence to obtain the matched filter sequence. The matched filter sequence contains the information of the Chirp signal and the index sequence. Therefore, the index bit data sequence and the modulation bit data sequence can be restored through the matched filter sequence, and then the transmission data can be restored according to the index bit data sequence and the modulation bit data sequence, thereby completing the data transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic flow chart of a data transmission method based on index modulation with a transmitter as the execution subject provided by an embodiment of the present invention;

[0042] Figure 2 A framework diagram of a transmitting end using a time slot index as an index carrier provided by an embodiment of the present invention;

[0043] Figure 3 A frame diagram of a receiving end using a time slot index as an index carrier provided by an embodiment of the present invention;

[0044] Figure 4 A schematic diagram of an index sequence using a time slot index as an index carrier provided by an embodiment of the present invention;

[0045] Figure 5 A framework diagram of a transmitting end using a carrier index as an index carrier provided by an embodiment of the present invention;

[0046] Figure 6 A frame diagram of a receiving end using a carrier index as an index carrier provided by an embodiment of the present invention;

[0047] Figure 7 An architecture diagram of a data transmission system based on index modulation provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0048] 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.

[0049] See also Figure 1 This embodiment provides a data transmission method based on index modulation, which can be applied to a transmitting end and specifically includes the following steps:

[0050] S1: Segment the transmission data to obtain an index bit set and a modulation bit set;

[0051] S2: Perform Chirp modulation on the modulated bit set to generate a Chirp signal;

[0052] S3: Map the index bit set based on the preset index carrier to generate an index sequence;

[0053] S4: Generate a data sequence based on the Chirp signal and the index sequence;

[0054] S5: Send the data sequence to the receiving end based on the preset index carrier, so that the receiving end obtains the matched filter sequence based on the data sequence, and then the receiving end obtains the index bit data sequence and the modulated bit data sequence based on the matched filter sequence, so that the receiving end restores the transmission data based on the index bit data sequence and the modulated bit data sequence.

[0055] In this embodiment, the transmission data is divided into an index bit set and a modulation bit set: wherein the modulation bit set is modulated into a Chirp signal that can be transmitted, and the index bit set is mapped to a preset index carrier as an index sequence sent as a Chirp signal, and then a data sequence that can be transmitted is generated based on the Chirp signal and the index sequence. The above process can effectively reduce the amount of transmitted data and improve the data transmission efficiency of the CSS. When the receiving end receives the data sequence, it only needs to perform matched filtering on the data sequence to obtain a matched filter sequence. The matched filter sequence contains information about the Chirp signal and the index sequence, so the index bit data sequence and the modulation bit data sequence can be restored through the matched filter sequence, and then the transmission data can be restored based on the index bit data sequence and the modulation bit data sequence, thereby completing the data transmission.

[0056] This embodiment divides the transmission data and cleverly maps part of the data into an index sequence for transmission, which greatly reduces the amount of the transmission data and can effectively improve the data transmission efficiency of the CSS.

[0057] Furthermore, the index bit set includes a plurality of index bits having a sequence; and the mapping of the index bits based on a preset index carrier to generate an index sequence includes:

[0058] Determining the number of carrier elements of the preset index carrier based on the number of modulation bits in the modulation bit set;

[0059] Get the vector element sequence based on the number of vector elements;

[0060] All the index bits are mapped one by one to corresponding carrier elements in the carrier element sequence in order, so as to generate an index sequence based on the carrier element sequence.

[0061] In this embodiment, there may be multiple types of index carriers, including time slot index and carrier index, etc. Different types of index carriers have different carrier elements. In order to ensure that all data in the modulation bit set can be transmitted, it is necessary to determine the number of carrier elements according to the number of modulation bits in the modulation bit set. For example, a carrier element has two states, and the carrier elements in different states can be simply represented as 0 and 1, that is, the carrier elements in two states can represent one modulation bit; therefore, if the number of modulation bits is 2, at least two carrier elements with two states are required. After determining the number of carrier elements, the carrier elements can be arranged in order to obtain a carrier element sequence, and the carrier elements in the carrier element sequence are not less than the number of index bits in the index bit set. Then, all index bits can be mapped one by one in order to the corresponding carrier elements in the carrier element sequence to generate an index sequence. For carrier elements in two states, one way to understand it is that the index bit assigns a value to each carrier element, and the value can represent the state of the carrier element.

[0062] It should be noted that the carrier element can also have three states. At this time, if the number of modulation bits is 3, it has eight cases, such as 000, 001, 010 and 011, which cannot be represented by one carrier element, but two carrier elements can represent nine cases, so only two carrier elements are needed to represent three modulation bits. Similarly, the carrier element can also have multiple states, as long as all index bits can be mapped one by one to the corresponding carrier elements in the carrier element sequence.

[0063] This embodiment uses the state combination of the carrier element sequence to characterize different numbers of index bits. After the subsequent data transmission process, the carrier element sequence can be analyzed by the different data transmission states, and then the corresponding index bit set can be estimated.

[0064] Further, generating a data sequence based on the Chirp signal and the index sequence includes:

[0065] The Chirp signal includes a plurality of sequential modulation bits;

[0066] Based on a preset transmission rule, a number of modulated bits on the Chirp signal are sequentially loaded onto an index sequence to generate a data sequence including a number of data elements.

[0067] In this embodiment, the preset transmission rule is used to determine the data carrying rule. Taking the carrier elements in two states as an example, or simply representing the carrier element states as 0 and 1, the preset transmission rule can be to carry every 0 or every 1, that is, a number of modulated bits on the Chirp signal will be carried to the 0 or 1 bit on the index sequence. Correspondingly, if it is carried every 0, then in the subsequent data transmission, only the carrier element in the 0 state will carry the modulated bit and be transmitted to the receiving end, so as to realize the transmission of the modulated bit. And the receiving end only needs to restore the carrier element sequence according to the type of index carrier and the number of the carrier element, and then estimate the corresponding index bit set.

[0068] It should be noted that if the index carrier is a time slot index and its carrier element is a time slot, then if it is carried every 0, the time slot in the 0 state will carry the modulation bit, that is, the modulation bit will be sent in the time slot, and conversely, the time slot in the 1 state will not carry the modulation bit, that is, the modulation bit will not be sent in the time slot. It should be noted that the definition of the 0 state and the 1 state depends on the preset transmission rule, and it can also be set to carry every 1.

[0069] Further, the index sequence is a binary sequence; based on a preset transmission rule, a number of modulated bits on the Chirp signal are sequentially loaded onto the index sequence to generate a data sequence including a number of data elements, including:

[0070] The preset transmission rule includes a rule for carrying every 0 or a rule for carrying every 1;

[0071] Based on the every-0 carrying rule or the every-1 carrying rule, a number of modulated bits on the Chirp signal are sequentially carried onto carrier elements corresponding to the index sequence to generate a data sequence including a number of data elements.

[0072] Further, the data sequence is sent to the receiving end based on a preset index carrier, so that the receiving end obtains a matched filter sequence based on the data sequence, and then the receiving end obtains an index bit data sequence and a modulated bit data sequence based on the matched filter sequence, so that the receiving end restores the transmission data based on the index bit data sequence and the modulated bit data sequence, including:

[0073] The data sequence is sent to the receiving end based on the preset index carrier, so that the receiving end performs the following steps:

[0074] Perform matched filtering on each data element in the data sequence in order to obtain a matched filtering sequence; each element in the matched filtering sequence has a unique element number;

[0075] Sequentially and according to the size of the data values, a preset first number of data elements with large data values ​​in the matched filter sequence are obtained as a modulated bit data sequence; the first number is the number of modulation bits in the modulation bit set;

[0076] Obtaining the element number of each data element in the modulated bit data sequence to obtain an element number sequence;

[0077] Based on the element number sequence, obtain the carrier element number;

[0078] Obtaining an index bit data sequence based on a carrier element number;

[0079] The transmission data is restored based on the index bit data sequence and the modulation bit data sequence.

[0080] In this embodiment, by confirming the first preset number of data elements with large data values ​​as the modulated bit data sequence, it is possible to estimate which data elements contain the modulated bits, and thus the modulated bit data sequence can be obtained. Then, the transmission rule of the modulated bits can be determined by the type of the index carrier and the preset transmission rule, that is, the element number sequence can obtain the carrier element number, and then the index bit data sequence can be obtained, and finally the transmission data can be restored based on the index bit data sequence and the modulated bit data sequence.

[0081] Further, in order to more clearly illustrate a data transmission method based on index modulation provided by the present invention, this embodiment provides a specific description using a preset index carrier as a time slot index to highlight the technical advantages of the present invention. Specifically, when the preset index carrier is a time slot index, the following can be used: Figure 2 The transmitter framework shown realizes the generation of data sequence, specifically including:

[0082] Assuming that the total number of bits of data transmitted in a symbol period is p, the bit splitter can be used to split the transmission data into two parts: the index bit set and the modulation bit set. Among them, the number of index bits in the index bit set is p1, and the number of modulation bits in the modulation bit set is p2. At this time, according to the number of modulation bits in the modulation bit set, it can be determined that the number of transmission time slots required for the time slot index is n. Among the n transmission time slots, p2 time slots will transmit signals, that is, all modulation bits in the modulation bit set are transmitted using p2 time slots, and there are a total of n transmission time slots. time slot combination, through this timeslot combination, can transmit additional Bit index bits, where represents the floor function.

[0083] See also Figure 2 As shown, the data transmission First, it is split into index bit sets and modulation bit set Then, the modulation bit set Chirp modulation can be performed by a Chirp modulator to generate p2 Chirp signals that need to be transmitted in p2 time slots. Then the index bit set The corresponding time slot combination can be selected by the index selector, that is, all index bits are mapped one by one to the transmission time slots corresponding to the transmission time slot sequence in order, thereby generating an index sequence [d1, d2, ..., d n ],in:

[0084]

[0085] where i = 1, 2, ..., n. Finally, by indexing the sequence [d1, d2, ..., d n ] and p2 Chirp signals that need to be transmitted in p2 transmission time slots, generating the data sequences [s1,s2,...,s n ], the generation method can be:

[0086] If d i = 0, then s i =0; if d i =1, the Chirp signal generated by the transmission modulator is transmitted. It should be noted that the Chirp signal generated by the transmission modulator is sent to p2 transmission time slots in order from small to large (i.e., i=1, 2, ..., p2) for transmission.

[0087] It should be noted that Chirp modulation can be implemented using a Chirp modulation scheme based on BOK modulation. That is, up chirp and down chirp signals are used to represent input data at the transmitter, such as up chirp represents data '1', and down chirp represents data '0'. Among them, the up chirp signal and the down chirp signal have very good cross-correlation characteristics, so using up chirp matched filters and down chirp matched filters at the receiving end, and sampling at the peak of the matching output can easily distinguish whether the received signal is an up chirp signal or a down chirp signal, and then restore the original information. The specific demodulation process can be as follows: directly sample and judge the outputs of the two matched filters. If the output of the up chirp matched filter is greater than or equal to the output of the down chirp matched filter, it is judged as '1', otherwise it is judged as '0'; if the chirp signal is a complex signal, only the real part needs to be judged.

[0088] For further information, see Figure 3 As shown, at the receiving end, the received signal of each transmission time slot is obtained by delaying, and the data sequence r(t) is obtained. Then, the received signal of each transmission time slot is processed using the up chirp matched filter and the down chirp matched filter respectively, and the outputs of the two matched filters of each transmission time slot are directly sampled and judged. If the output of the up chirp matched filter of the i-th time slot is greater than or equal to the output of the down chirp matched filter, the output of the up chirp matched filter is retained and stored in R i Otherwise, the output of the down chirp matched filter is retained and stored in R i In this way, the matched filter sequence R = [R1, R2, ..., R n ]. Then, select the p2 largest values ​​from the output of the matched filter in these n transmission time slots, that is:

[0089]

[0090] pass The result of p2 modulation bits can be estimated, that is, the modulation bit data sequence is obtained. At the same time, the index value of the p2 largest value is recorded, that is, the element number sequence is obtained, which is:

[0091]

[0092] The sequence of the p2 chirp signal transmission slots can be obtained through the element number sequence, that is, the transmission slot number. Therefore, the estimated value of the slot combination can be obtained according to the transmission slot number, and finally the estimated value of the index bit can be obtained, that is, the index bit data sequence. The transmission data can be restored according to the index bit data sequence and the modulation bit data sequence.

[0093] It should be noted that the transmission time slot Δt determined at the transmitting end is a delay time, and the role of the index bit is to determine whether each transmission time slot Δt transmits a modulated bit. Based on this, when the receiving end receives data, it will perform a corresponding delay according to the transmission time slot Δt, and then obtain the corresponding data sequence to ensure signal alignment.

[0094] The data transmission method based on index modulation using time slot index as index carrier proposed in this embodiment increases the transmission rate by 300% when n=4 and p2=2; increases the transmission rate by 700% when n=8 and p2=3; and increases the transmission rate by 900% when n=8 and p2=5. It can be concluded that as n increases, the index space increases continuously, so more index bits can be transmitted. Therefore, the transmission rate of the proposed data transmission method is greatly improved.

[0095] Furthermore, the index selector can determine on which time slots to transmit the modulation bits according to the index bits. Figure 4 . Figure 4 In the example, the number of index bits is 2 and the number of transmission slots is 4. When the index bits are 00, you can select Figure 4 (a) to transmit the modulated bits; when the index bit is 01, you can choose Figure 4 (b) to transmit the modulated bits; when the index bit is 10, you can choose Figure 4 (c) to transmit the modulated bits; when the index bit is 11, you can choose Figure 4 (d) to transmit the modulated bits in the transmission time slot.

[0096] The data transmission method proposed in this embodiment uses different time slot combinations to transmit data, and can transmit index bits additionally, which greatly improves the transmission rate of the traditional chirp modulation scheme, significantly improves the efficiency of data transmission, and meets the needs of more users for high-speed Internet. It is especially suitable for scenarios with high transmission rate requirements in the Internet of Things. This not only supports smoother online video streaming and faster file downloads, but also promotes the development of emerging technologies such as virtual reality, augmented reality, and high-definition video conferencing. In addition, high-speed transmission rates are crucial to ensure real-time communication between IoT devices, and help improve the performance of industrial automation and smart city applications. In emergency situations, such as disaster response and telemedicine, faster transmission rates can also improve the reliability and response speed of communications, which may save lives. In general, increasing transmission rates plays an important role in promoting economic growth, improving user experience, and supporting technological progress.

[0097] Further, in order to more clearly illustrate a data transmission method based on index modulation provided by the present invention, this embodiment provides a specific description using a preset index carrier as a carrier index to highlight the technical advantages of the present invention. Specifically, when the preset index carrier is a carrier index, the following can be used: Figure 5 The transmitter framework shown realizes the generation of data sequence, specifically including:

[0098] Assuming that the total number of bits of data transmitted in a symbol period is p, the bit splitter can be used to split the transmitted data into two parts: the index bit set and the modulation bit set. Among them, the number of index bits in the index bit set is p1, and the number of modulation bits in the modulation bit set is p2. At this time, according to the number of modulation bits in the modulation bit set, it can be determined that the number of carriers required for carrier index is n. Among the n carriers, p2 carriers will be activated, that is, they will be used to transmit signals, that is, all the modulation bits in the modulation bit set are transmitted using these p2 activated carriers, a total of Carrier activation mode, through this Carrier activation mode, which can transmit additional Bit index bits, where represents the floor function.

[0099] See also Figure 5 As shown, the data transmission First, it is split into index bit sets and modulation bit set Then, the modulation bit set Chirp modulation can be performed by a Chirp modulator to generate p2 Chirp signals that need to be transmitted on p2 activated carriers. Then the index bit set Different carrier activation modes can be selected by mapping, that is, all index bits are mapped one by one to the activated carriers corresponding to the carrier activation sequence in order, thereby generating an index sequence [d1, d2, ..., d n ],in:

[0100]

[0101] where i = 1, 2, ..., n. Finally, by indexing the sequence [d1, d2, ..., d n ] and p2 Chirp signals that need to be transmitted on p2 activated carriers, generating data sequences [s1, s2, ..., s n ], the generation method can be:

[0102] If d i =0, indicating that the i-th carrier is not activated, then s i =0; if d i =1, the Chirp signal generated by the transmission modulator. It should be noted that the Chirp signal generated by the transmission modulator is sequentially sent to the p2 activated carriers in order from small to large (i.e., i=1, 2, ..., p2) for transmission.

[0103] For further information, see Figure 6 As shown, at the receiving end, the received signal of each carrier can be obtained by carrier frequency recovery to obtain the data sequence r(t). Then, each carrier is processed using the up chirp matched filter and the down chirp matched filter, and the outputs of the two matched filters of each carrier are directly sampled and judged. If the output of the up chirp matched filter of the i-th carrier is greater than or equal to the output of the down chirp matched filter, the output of the up chirp matched filter is retained and stored in R i Otherwise, the output of the down chirp matched filter is retained and stored in R i In this way, we get the matched filter sequence R = [R1, R2, ..., R n Then, the p2 largest values ​​are selected from the outputs of the matched filters of the n carriers, namely:

[0104]

[0105] pass The result of p2 modulation bits can be estimated, that is, the modulation bit data sequence is obtained. At the same time, the index value of the p2 largest value is recorded, that is, the element number sequence is obtained, which is:

[0106]

[0107] The sequence of the p2 carriers transmitting the chirp signal can be obtained through the element number sequence, that is, the activated carrier number. Therefore, the estimated value of the carrier activation mode can be obtained according to the activated carrier number, and finally the estimated value of the index bit can be obtained, that is, the index bit data sequence. The transmission data can be restored according to the index bit data sequence and the modulation bit data sequence.

[0108] It should be noted that mapping all index bits one by one to the activated carrier corresponding to the carrier activation sequence in order can be understood as follows: when the total number of carriers n = 4 and the number of modulation bits is p2 = 2, there are 6 carrier activation modes at this time, and 4 of them can be selected for use in actual operation, and a total of p1 = 2 index bits can be transmitted. At this time, the mapping relationship between the index bits can be set as follows: when the index bit is 00, the carrier activation mode is [1,1,0,0] (where the four numbers in the vector represent the activation status of the four carriers, 0 indicates that the carrier is not activated, and 1 indicates that the carrier is activated); when the index bit is 01, the carrier activation mode is [0,1,1,0]; when the index bit is 10, the carrier activation mode is [0,0,1,1]; when the index bit is 11, the carrier activation mode is [1,0,0,1].

[0109] The data transmission method based on index modulation using carrier index as the index carrier proposed in this embodiment increases the transmission rate by 300% when n=4 and p2=2; increases the transmission rate by 700% when n=8 and p2=3; and increases the transmission rate by 900% when n=8 and p2=5. It can be concluded that as n increases, the index space continues to increase, so more index bits can be transmitted. At the same time, the number of modulation bits also increases with the increase of p2, and the transmission rate of the proposed data transmission method based on carrier index is greatly improved.

[0110] It should be noted that although the method proposed in this embodiment sacrifices some spectrum resources, it can greatly increase the transmission efficiency. That is, this embodiment is suitable for scenarios that do not require high spectrum resources but have high requirements for time efficiency and space resource utilization.

[0111] The data transmission method proposed in this embodiment uses different carrier activation modes to transmit data, and can transmit index bits additionally, which greatly improves the transmission rate of the traditional chirp modulation scheme, significantly improves the efficiency of data transmission, and meets the needs of more users for high-speed Internet. It is especially suitable for scenarios with high transmission rate requirements in the Internet of Things. This not only supports smoother online video streaming and faster file downloads, but also promotes the development of emerging technologies such as virtual reality, augmented reality, and high-definition video conferencing. In addition, high-speed transmission rates are crucial to ensuring real-time communication between IoT devices, and help improve the performance of industrial automation and smart city applications. In emergency situations, such as disaster response and telemedicine, faster transmission rates can also improve the reliability and response speed of communications, which may save lives. In general, increasing transmission rates plays an important role in promoting economic growth, improving user experience, and supporting technological progress.

[0112] See also Figure 7 This embodiment further proposes a data transmission system based on index modulation, which can apply the above-mentioned data transmission method based on index modulation, and the system includes a transmitting end and a receiving end; wherein the transmitting end includes a bit segmentation module, a modulation module, an index generation module, a data generation module and a data sending module; the receiving end includes a data receiving module, a matched filtering module, a sequence acquisition module and a data restoration module; wherein:

[0113] The bit segmentation module is used to segment the transmission data to obtain the index bit set and the modulation bit set; the modulation module is used to perform Chirp modulation on the modulation bit set to generate a Chirp signal; the index generation module is used to map the index bit set based on a preset index carrier to generate an index sequence; the data generation module is used to generate a data sequence based on the Chirp signal and the index sequence; the data sending module is used to send the data sequence to the receiving end; the data receiving module is used to receive the data sequence; the matched filtering module is used to obtain the matched filtering sequence based on the data sequence; the sequence acquisition module is used to obtain the index bit data sequence and the modulation bit data sequence based on the matched filtering sequence; the data restoration module is used to restore the transmission data based on the index bit data sequence and the modulation bit data sequence.

[0114] The system architecture provided by this embodiment is simple and has strong applicability. It can directly implement a data transmission method based on index modulation, and divide the transmission data into an index bit set and a modulation bit set: wherein the modulation bit set is modulated into a Chirp signal that can be transmitted, and the index bit set is mapped to a preset index carrier as an index sequence sent as a Chirp signal, and then a data sequence that can be transmitted is generated according to the Chirp signal and the index sequence. The above process can effectively reduce the amount of transmitted data and improve the data transmission efficiency of CSS. When the receiving end receives the data sequence, it only needs to perform matched filtering on the data sequence to obtain the matched filter sequence. The matched filter sequence contains the information of the Chirp signal and the index sequence. Therefore, the index bit data sequence and the modulation bit data sequence can be restored through the matched filter sequence, and then the transmission data can be restored according to the index bit data sequence and the modulation bit data sequence, thereby completing the data transmission.

[0115] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A data transmission method based on index modulation, characterized in that: Applied to the transmitter, the following steps are included: Segment the transmission data to obtain an index bit set and a modulation bit set; Performing Chirp modulation on the modulation bit set to generate a Chirp signal; Mapping the index bit set based on a preset index carrier to generate an index sequence; Generate a data sequence based on the Chirp signal and the index sequence; The data sequence is sent to the receiving end based on the preset index carrier, so that the receiving end obtains the matched filter sequence based on the data sequence, and then the receiving end obtains the index bit data sequence and the modulation bit data sequence based on the matched filter sequence, so that the receiving end restores the transmission data based on the index bit data sequence and the modulation bit data sequence.

2. The data transmission method based on index modulation according to claim 1, characterized in that: The index bit set includes a plurality of index bits having a sequence; the mapping of the index bits based on a preset index carrier to generate an index sequence includes: Determining the number of carrier elements of the preset index carrier based on the number of modulation bits in the modulation bit set; Get the vector element sequence based on the number of vector elements; All the index bits are mapped one by one to corresponding carrier elements in the carrier element sequence in order, so as to generate an index sequence based on the carrier element sequence.

3. The data transmission method based on index modulation according to claim 2, characterized in that: The step of generating a data sequence based on the Chirp signal and the index sequence includes: The Chirp signal includes a plurality of sequential modulation bits; Based on a preset transmission rule, a number of modulated bits on the Chirp signal are sequentially loaded onto an index sequence to generate a data sequence including a number of data elements.

4. The data transmission method based on index modulation according to claim 3, characterized in that: The index sequence is a binary sequence; based on a preset transmission rule, a plurality of modulated bits on the Chirp signal are sequentially loaded onto the index sequence to generate a data sequence including a plurality of data elements, including: The preset transmission rule includes a rule for carrying every 0 or a rule for carrying every 1; Based on the every-0 carrying rule or the every-1 carrying rule, a number of modulated bits on the Chirp signal are sequentially carried onto carrier elements corresponding to the index sequence to generate a data sequence including a number of data elements.

5. The data transmission method based on index modulation according to claim 3, characterized in that: The method of sending the data sequence to the receiving end based on the preset index carrier so that the receiving end obtains the matched filter sequence based on the data sequence, and then the receiving end obtains the index bit data sequence and the modulated bit data sequence based on the matched filter sequence, so that the receiving end restores the transmission data based on the index bit data sequence and the modulated bit data sequence, includes: The data sequence is sent to the receiving end based on the preset index carrier, so that the receiving end performs the following steps: Perform matched filtering on each data element in the data sequence in order to obtain a matched filtering sequence; each element in the matched filtering sequence has a unique element number; Sequentially and according to the size of the data values, a preset first number of data elements with large data values ​​in the matched filter sequence are obtained as a modulated bit data sequence; the first number is the number of modulation bits in the modulation bit set; Obtaining the element number of each data element in the modulated bit data sequence to obtain an element number sequence; Based on the element number sequence, obtain the carrier element number; Obtaining an index bit data sequence based on a carrier element number; The transmission data is restored based on the index bit data sequence and the modulation bit data sequence.

6. The data transmission method based on index modulation according to claim 2, characterized in that: When the preset index carrier is a time slot index, mapping the index bits based on the preset index carrier to generate an index sequence includes: Determining the number of transmission time slots required for the time slot index based on the number of modulation bits in the modulation bit set; Obtaining a transmission time slot sequence based on the number of transmission time slots; All the index bits are mapped one by one in sequence to the transmission time slots corresponding to the transmission time slot sequence, so as to generate an index sequence based on the transmission time slot sequence.

7. The data transmission method based on index modulation according to claim 6, characterized in that: When the preset index carrier is a time slot index, the data sequence is sent to the receiving end based on the preset index carrier, so that the receiving end obtains a matched filter sequence based on the data sequence, and then the receiving end obtains an index bit data sequence and a modulated bit data sequence based on the matched filter sequence, so that the receiving end restores the transmission data based on the index bit data sequence and the modulated bit data sequence, including: Each data element in the data sequence is sent to the receiving end one by one in sequence based on the preset time slot, so that the receiving end performs the following steps: Perform matched filtering on each data element in the data sequence in order to obtain a matched filtering sequence; each element in the matched filtering sequence has a unique element number; Sequentially and according to the size of the data values, a preset first number of data elements with large data values ​​in the matched filter sequence are obtained as a modulated bit data sequence; the first number is the number of modulation bits in the modulation bit set; Obtaining the element number of each data element in the modulated bit data sequence to obtain an element number sequence; Based on the element number sequence, obtaining a transmission time slot number; Acquire an index bit data sequence based on a transmission time slot number; The transmission data is restored based on the index bit data sequence and the modulation bit data sequence.

8. The data transmission method based on index modulation according to claim 2, characterized in that: When the preset index carrier is a carrier index, mapping the index bits based on the preset index carrier to generate an index sequence includes: Determining the number of carriers required for the carrier index based on the number of modulation bits in the modulation bit set; Obtaining a carrier activation sequence based on the number of carriers; All the index bits are mapped one by one in sequence to the carriers corresponding to the carrier activation sequence, so as to generate an index sequence based on the carrier activation sequence.

9. The data transmission method based on index modulation according to claim 8, characterized in that: When the preset index carrier is a carrier index, the data sequence is sent to the receiving end based on the preset index carrier, so that the receiving end obtains a matched filter sequence based on the data sequence, and then the receiving end obtains an index bit data sequence and a modulated bit data sequence based on the matched filter sequence, so that the receiving end restores the transmission data based on the index bit data sequence and the modulated bit data sequence, including: Each data element in the data sequence is sent to the receiving end based on the preset carrier, so that the receiving end performs the following steps: Perform matched filtering on each data element in the data sequence in order to obtain a matched filtering sequence; each element in the matched filtering sequence has a unique element number; Sequentially and according to the size of the data values, a preset first number of data elements with large data values ​​in the matched filter sequence are obtained as a modulated bit data sequence; the first number is the number of modulation bits in the modulation bit set; Obtaining the element number of each data element in the modulated bit data sequence to obtain an element number sequence; Based on the element number sequence, obtain the carrier activation number; An index bit data sequence is obtained based on the carrier activation number.

10. The data transmission system based on index modulation according to claim 1, characterized in that: A data transmission method based on index modulation as claimed in any one of claims 1 to 9 is applied, the system comprising a transmitting end and a receiving end; wherein the transmitting end comprises a bit segmentation module, a modulation module, an index generation module, a data generation module and a data sending module; the receiving end comprises a data receiving module, a matched filtering module, a sequence acquisition module and a data restoration module; wherein: The bit segmentation module is used to segment the transmission data to obtain an index bit set and a modulation bit set; The modulation module is used to perform Chirp modulation on the modulation bit set to generate a Chirp signal; The index generation module is used to map the index bit set based on a preset index carrier to generate an index sequence; The data generation module is used to generate a data sequence based on the Chirp signal and the index sequence; The data sending module is used to send a data sequence to a receiving end; The data receiving module is used to receive a data sequence; The matched filtering module is used to obtain a matched filtering sequence based on the data sequence; The sequence acquisition module is used to acquire an index bit data sequence and a modulation bit data sequence based on a matched filter sequence; The data restoration module is used to restore the transmission data based on the index bit data sequence and the modulation bit data sequence.

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