A data transmission method, device and system of a discrete narrowband wireless system

Abstract

The application provides a data transmission method, device and system of a discrete narrowband wireless system, and relates to the technical field of power wireless communication, and the method comprises the following steps: determining a preset wireless frame structure; the frame length of the preset wireless frame structure is 10ms, and the preset wireless frame structure comprises four time slots and one guard interval; based on the preset wireless frame structure, transmitting the data to be transmitted; the working frequency band of the discrete narrowband wireless system is 223-235MHz, the single-carrier bandwidth is 25kHz, and the subcarrier spacing in the carrier is 2.5kHz. The frame length of the wireless frame structure designed in the application is 10ms, which is shorter than the frame length 25ms of the LTE-G frame structure, and meets the transmission requirements of low-latency transmission services; meanwhile, the subcarrier spacing in the carrier is 2.5kHz, which is smaller than the subcarrier spacing 3.75kHz of the IOT-G, and the number of subcarriers contained in a single carrier is more than that of the IOT-G, thereby improving the comprehensive time-frequency efficiency of data transmission.

Description

Technical Field

[0001] This invention relates to the field of power wireless communication technology, and specifically to a data transmission method, apparatus, and system for a discrete narrowband wireless system. Background Technology

[0002] In existing technologies, power line wireless private networks based on 230MHz have two frame structures. The first is the frame structure scheme adopted by the LTE-G (Long Term Evolution) 230MHz system, which proposes a frame length of 25ms and includes 5 subframes. Subframe 0 is used for downlink transmission, subframe 1 is a special subframe including downlink pilot time slot (DwPTS), guard time slot (GP), and uplink pilot time slot (UpPTS), and subframes 2, 3, and 4 are all used for uplink transmission. Each subframe includes 9 OFDM (Orthogonal Frequency Division Multiplexing) symbols. The second approach is the frame structure scheme adopted by the IOT-G (Internet of Things-Grid) 230MHz system. This scheme proposes a 10ms frame length, with each wireless frame consisting of five 2ms time slots. Time slots 0 and 1 are downlink time slots, time slot 2 is a special time slot, and time slots 3 and 4 are uplink time slots. Time slot 2 includes a downlink pilot time slot (DwPTS), a guard time slot (GaP), and an uplink pilot time slot (UpPTS). Each time slot contains six OFDM symbols.

[0003] The existing LTE-G230MHz system has a frame length of 25ms, which is too long and cannot meet the low latency transmission requirements of power services. In addition, it has low spectral efficiency and overall time-frequency efficiency. The subcarrier spacing of IOT-G MHz is 3.75kHz, which contains fewer subcarriers under a single carrier, thus causing problems with low spectral efficiency and overall time-frequency efficiency. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, in a first aspect, the present invention provides a data transmission method for a discrete narrowband wireless system, comprising:

[0005] Determine the preset radio frame structure; the frame length of the preset radio frame structure is 10ms, and the preset radio frame structure includes 4 time slots and 1 guard interval;

[0006] Based on the preset wireless frame structure, the data to be transmitted is transmitted.

[0007] The operating frequency band of the discrete narrowband wireless system is 223–235 MHz, the single carrier bandwidth is 25 kHz, and the subcarrier spacing in the carrier is 2.5 kHz.

[0008] Optionally, the four time slots of the preset radio frame structure include: time slot 0, time slot 1, time slot 2, and time slot 3;

[0009] Time slots 0 and 1 form the downlink data transmission time slot, and time slots 2 and 3 form the uplink data transmission time slot. The guard interval (GAP) is used to isolate uplink and downlink data.

[0010] Optionally, the radio frame structure includes 21 orthogonal frequency division multiplexing (OFDM) symbols, each OFDM symbol having a length of 9472*T. C ;

[0011] Time slots 0, 1, and 3 each contain 5 OFDM symbols, and their lengths are 47360*T. C The second time slot includes 6 OFDM symbols, and its length is 56832*T. C ;

[0012] The basic unit for the time-domain value of OFDM symbol length is T. C T C It is 48.828 ns.

[0013] Optionally, the length of an OFDM symbol includes the data length and the cyclic prefix (CP) length, where the data length in the OFDM symbol length is 8192*T. C The CP length is 1280*T C .

[0014] Optionally, when the subcarrier spacing in the carrier is 2.5kHz, the number of subcarriers in the carrier is 7 or 9, and the modulation scheme is 256QAM.

[0015] Optionally, the length of the guard interval (GAP) in the preset wireless frame structure is 287.5 µs.

[0016] Optionally, a superframe consists of 1024 radio frames, with a frame length of 10240ms.

[0017] In a second aspect, the present invention also provides a communication device, comprising:

[0018] The processing module is used to determine the preset radio frame structure; the frame length of the preset radio frame structure is 10ms, and the preset radio frame structure includes 4 time slots and 1 guard interval.

[0019] The communication module is used to transmit data to be transmitted based on a preset wireless frame structure.

[0020] The communication device operates in the frequency band of 223–235 MHz, with a single carrier bandwidth of 25 kHz and a subcarrier spacing of 2.5 kHz.

[0021] Thirdly, the present invention also provides a data transmission method for a discrete narrowband wireless system, comprising:

[0022] Receive transmission frames. The frame length of the transmission frame is 10ms. The frame structure of the transmission frame includes 4 time slots and 1 guard interval.

[0023] Obtain data from the transmission frame;

[0024] The operating frequency band of the discrete narrowband wireless system is 223–235 MHz, the single carrier bandwidth is 25 kHz, and the subcarrier spacing in the carrier is 2.5 kHz.

[0025] Fourthly, the present invention also provides a communication device, comprising:

[0026] A communication module is used to receive transmission frames, the frame length of which is 10ms, and the frame structure of which includes 4 time slots and 1 guard interval.

[0027] A processing module is used to obtain data from the transmission frame;

[0028] The communication device operates in the frequency band of 223–235 MHz, has a single carrier bandwidth of 25 kHz, and a subcarrier spacing of 2.5 kHz.

[0029] Fifthly, the present invention also provides a communication system, including a transmitting end and a receiving end; the transmitting end is used to implement the data transmission method of the discrete narrowband wireless system described in the first aspect above, and the receiving end is used to implement the data transmission method of the discrete narrowband wireless system described in the third aspect above.

[0030] In a sixth aspect, the present invention also provides an electronic device, comprising: at least one processor and a memory; said memory and processor are connected via a bus;

[0031] The memory is used to store one or more programs;

[0032] When the one or more programs are executed by the at least one processor, they implement the data transmission method for a discrete narrowband wireless system as described in the first aspect above, or the data transmission method for a discrete narrowband wireless system as described in the third aspect above.

[0033] In a seventh aspect, the present invention also provides a readable storage medium having an executable program stored thereon, wherein when the executable program is executed, it implements the data transmission method for a discrete narrowband wireless system as described in the first aspect above, or the data transmission method for a discrete narrowband wireless system as described in the third aspect above.

[0034] Compared with the closest existing technology, the present invention has the following beneficial effects:

[0035] This invention provides a data transmission method for a discrete narrowband wireless system, comprising: determining a preset wireless frame structure; the preset wireless frame structure has a frame length of 10ms and includes 4 time slots and 1 guard interval; transmitting data to be transmitted based on the preset wireless frame structure; the discrete narrowband wireless system operates in the frequency band of 223–235MHz, has a single carrier bandwidth of 25kHz, and a subcarrier spacing of 2.5kHz. This invention, by designing a wireless frame structure with a frame length of 10ms, shorter than the 25ms frame structure of LTE-G 230MHz, can meet the transmission requirements of low-latency transmission services; the subcarrier spacing of the carrier in this data transmission method is 2.5kHz, less than the 3.75kHz subcarrier spacing of LTE-G 230MHz, and the number of subcarriers contained in a single carrier is greater than that of LTE-G 230MHz, significantly improving the overall time-frequency efficiency of data transmission. Attached Figure Description

[0036] Figure 1 A schematic flowchart of a data transmission method for a discrete narrowband wireless system provided by the present invention;

[0037] Figure 2 This is a schematic diagram of the wireless frame structure provided by the present invention;

[0038] Figure 3 A schematic diagram of the structure of an OFDM symbol provided by the present invention;

[0039] Figure 4 This is a schematic diagram of the structure of the superframe provided by the present invention;

[0040] Figure 5 This is a schematic diagram of the frame structure of the existing LTE-G 230MHz technology;

[0041] Figure 6 This is a schematic diagram of the frame structure of existing OT-G 230MHz technology;

[0042] Figure 7 This is a schematic diagram of the communication system of the present invention;

[0043] Figure 8 This is a schematic diagram of the communication device of the present invention;

[0044] Figure 9 A schematic diagram of the electronic device provided by the present invention. Detailed Implementation

[0045] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0046] Example 1:

[0047] This invention provides a data transmission method for a discrete narrowband wireless system, specifically, Figure 1 A schematic flowchart of a data transmission method for a discrete narrowband wireless system provided in an embodiment of the present invention is shown in the figure, including the following steps:

[0048] S1: The transmitting end determines the preset radio frame structure; the frame length of the preset radio frame structure is 10ms, and the preset radio frame structure includes 4 time slots and 1 guard interval;

[0049] S2: The transmitting end transmits the data to be transmitted based on the preset wireless frame structure;

[0050] Correspondingly, the receiving end receives the transmission frame, the frame length of which is 10ms, and the frame structure of the transmission frame includes 4 time slots and 1 guard interval.

[0051] S3: The receiving end obtains data from the transmitted frame.

[0052] The operating frequency band of the discrete narrowband wireless system is 223–235 MHz, the single carrier bandwidth is 25 kHz, and the subcarrier spacing in the carrier is 2.5 kHz.

[0053] This invention designs a wireless frame structure with a frame length of 10ms, shorter than the 25ms frame structure of LTE-G 230MHz, which can meet the transmission requirements of low-latency transmission services. At the same time, the subcarrier spacing in the carrier is 2.5KHz, which is smaller than the subcarrier spacing of 3.75kHz in IOT-G. The number of subcarriers contained in a single carrier is more than that in IOT-G 230MHz, which significantly improves the overall time and frequency efficiency of data transmission.

[0054] The data transmission method for a discrete narrowband wireless system provided by this invention determines a preset wireless frame structure with a frame length of 10ms and a structure of "DDGUU", including 4 time slots and 1 guard interval (GAP). Figure 2 The diagram shown is a schematic representation of the wireless frame structure provided by the present invention.

[0055] like Figure 2As shown, the four time slots of the preset wireless frame structure include: time slot 0, time slot 1, time slot 2, and time slot 3; among them, time slot 0 and time slot 1 constitute the downlink data transmission time slots, and time slot 2 and time slot 3 constitute the uplink data transmission time slots. The guard interval (GAP) is not used for data transmission but is used to isolate uplink and downlink data.

[0056] The preset radio frame structure includes 21 OFDM (Orthogonal Frequency Division Multiplexing) symbols, of which time slots 0, 1, and 3 each include 5 OFDM symbols, time slot 2 includes 6 OFDM symbols, and the guard interval does not include OFDM symbols.

[0057] The basic unit for the time-domain value of OFDM symbol length is T. C T C The duration is 48.828 ns; the length of each OFDM symbol is 9472*T. C = 9472 * 48.828 ns = 462.5 μs. Therefore, the lengths of time slots 0, 1, and 3 are 9472 * 5 * T respectively. C =47360*T C =2312.5us; the length of the second time slot is 9472*6*T C =56832*T C =2775us.

[0058] The length of the guard interval (GAP) without a preset frame structure is 287.5 µs. Based on the GAP length designed in this invention, its theoretical maximum transmission distance is 287.5 µs / 2 / (3*10^8 m / s) = 43.125 km, which meets the base station coverage distance design requirements. Compared with the frame structure design schemes of traditional LTE-G 230MHz and IOT-G 230MHz wireless private network systems, the downlink pilot time slot (DwPTS) and uplink pilot time slot (UpPTS) are eliminated, further improving the effective data transmission time.

[0059] like Figure 3 The diagram shows the structure of an OFDM symbol. An OFDM symbol has a length of 462.5 µs, including the data length and the cyclic prefix (CP) length. The CP length is 1280 * T. C =1280 * 48.828 ns = 62.5 μs, data length is 8192 * T C =8192 * 48.828 ns = 400 μs. CP percentage is 62.5 μs / 462.5 μs = 13.5%.

[0060] The discrete narrowband wireless system of the present invention operates in the frequency band of 223-235MHz, has a single carrier bandwidth of 25kHz, a subcarrier spacing of 2.5kHz, contains 7 or 9 subcarriers in a single carrier, and uses 256QAM modulation.

[0061] QAM (Quadrature Amplitude Modulation) modulates a signal by simultaneously changing its amplitude and phase, belonging to non-constant envelope two-dimensional modulation. QAM is a combination of quadrature carrier modulation technology and multilevel amplitude shifting.

[0062] 64QAM (64-Quadrature Amplitude Modulation) is a 64th-order quadrature amplitude modulation. Each OFDM symbol can represent 6 bits of data, and there are 6 amplitude and 6 phase combinations, using 64 different symbol states.

[0063] 256QAM (256-Quadrature Amplitude Modulation) is a 256th-order quadrature amplitude modulation. Each OFDM symbol can represent 8 bits of data, with 8 amplitude and 8 phase combinations, and uses 256 different symbol states.

[0064] In this invention, a single carrier contains 7 or 9 subcarriers. The width of 7 subcarriers is 17.5 kHz, the width of 9 subcarriers is 22.5 kHz, and the width of both 7 and 9 subcarriers is less than 25 kHz.

[0065] Figure 4 This is a schematic diagram of the structure of the superframe provided by the present invention. Figure 4 As shown, a superframe consists of 1024 radio frames, which are cyclically numbered from 1 to 1023. The symbol for a superframe is T. hf The length T of the superframe hf =1024*10ms=10240ms.

[0066] The length of 1024 superframes is 1024T. hf =1024*10240ms=10485760ms=2h54min45s760ms.

[0067] A superframe is a unit of time that defines the time interval for data transmission. Its purpose is to add control and synchronization functions to the CPRI (Common Public Radio Interface) protocol, which helps to improve the flexibility and efficiency of data transmission in 5G networks.

[0068] The effects of the technical solution of the present invention will be explained in detail below in conjunction with existing technologies such as LTE-G 230MHz and IOT-G 230MHz systems.

[0069] like Figure 5 The diagram shows the frame structure of a conventional LTE-G 230MHz system. Its radio frame structure has a frame length of 25ms, consisting of five subframes, each 5ms long. These five subframes are designated as subframe 0, subframe 1, subframe 2, subframe 3, and subframe 4. Subframe 0 is a downlink subframe used for downlink transmission. Subframe 1 is a special subframe, including a downlink pilot time slot (DwPTS), a guard time slot (GP), and an uplink pilot time slot (UpPTS). Subframes 2, 3, and 4 are uplink subframes used for uplink transmission.

[0070] In the frame structure of the LTE-G 230MHz system, each subframe includes 9 Orthogonal Frequency Division Multiplexing (OFDM) symbols. Among them, the first subframe is a special subframe, with DwPTS and UpPTS each occupying 4 OFDM symbols, and GP occupying 1 OFDM symbol.

[0071] The length of each subframe is 640*T S T S It is the basic unit for taking values ​​in the time domain, T S = 1 / (2000*64)s. Each subframe consists of 9 OFDM symbols, each with a length of 0.5ms, and the total CP length of the 9 OFDM symbols is 0.5ms. Among them, the CP length of the first OFDM symbol in each subframe is 62.5us, and the CP length of the remaining 8 OFDM symbols is 54.7us.

[0072]

[0073] CP length of OFDM symbol in LTE-G 230MHz system (unit: T) S )as follows:

[0074]

[0075] In the formula, I is the OFDM / SC-FDMA sequence number within a subframe;

[0076] N CP,I — The CP length of the I-th OFDM symbol in the LTE-G 230MHz system.

[0077] Among them, SC-FDMA (Single-carrier Frequency-Division Multiple Access) is the mainstream multiple access method for the uplink of LTE.

[0078] As can be seen from the above, the CP length of OFDM symbols in the LTE-G 230MHz system varies, which complicates the system design.

[0079] The peak spectral efficiency of the LTE-G 230MHz system is calculated as follows:

[0080] LTE-G supports 64QAM modulation, and the peak spectral efficiency is estimated as follows:

[0081] The amount of data transmitted in one carrier and one subframe in LTE-G is: number of subcarriers * number of symbols * modulation order = 11 * 9 * 6 = 594 bits. Peak spectral efficiency = amount of data transmitted / frame length / bandwidth = 594 bits / 5ms / 25KHz = 4.64bps / Hz.

[0082] like Figure 6 The diagram shown illustrates the frame structure of a current IoT-G 230MHz system. Its wireless frame length is 10ms, or 1 frame T. f = 1 / 3ms A radio frame consists of 5 time slots, each 2ms in length. These 5 time slots are designated as time slot 0, time slot 1, time slot 2, time slot 3, and time slot 4. Time slots 0 and 1 are downlink time slots, and time slots 0 and 2 together form a downlink subframe. T DLsf = 4ms; the second time slot is a special time slot, including the downlink pilot time slot (DwPTS), guard time slot (GP), and uplink pilot time slot (UpPTS), with the downlink pilot time slot T... DL = 1 / 3 ms, protection slot T gap = 1 / 3ms, uplink pilot time slot T UL =1ms; the 3rd and 4th time slots are uplink time slots, and the 3rd and 4th time slots form an uplink subframe, T ULsf = 4ms.

[0083] In the frame structure of the IoT-G 230MHz system, each time slot includes 6 orthogonal frequency division multiplexing (OFDM) symbols. Among them, the DwPTS in the second time slot occupies 1 OFDM symbol, the guard time slot GP occupies 2 OFDM symbols, and the UpPTS occupies 3 OFDM symbols.

[0084] Each time slot T slot The length is 120*T S =2ms,T S It is the basic unit for taking values ​​in the time domain, TS = 1 / 60000s. The length of each OFDM symbol is 1 / 3ms. Among them, the cyclic prefix (CP) length of each OFDM symbol in each time slot is 66.7us, and the proportion of CP length in each time slot is 66.7us / (1 / 3ms) = 20%.

[0085] The IoT-G 230MHz system has a frame length of 10ms, but its subcarrier spacing is 3.75kHz. A single 25kHz carrier is divided into 6 subcarriers, resulting in a bandwidth of 26.25kHz. This exceeds the 25kHz bandwidth limit of the main lobe, leading to signal degradation on the edge subcarriers and interference with adjacent subcarriers, making it difficult to guarantee the transmission quality of the edge subcarriers. Therefore, complex high-order filters are required for forced clipping, resulting in loss of useful signal capability and signal distortion. Furthermore, the excessively long tail necessitates the use of a longer cyclic prefix (CP).

[0086] The peak spectral efficiency of the IOT-G 230MHz system is calculated as follows:

[0087] IoT-G supports 64QAM modulation, and the peak spectral efficiency is estimated as follows:

[0088] The amount of data transmitted by IoT-G in one carrier and one time slot is: number of subcarriers * number of symbols * modulation order = 6 * 6 * 6 = 216 bits. Peak spectral efficiency = amount of data transmitted / frame length / bandwidth = 216 bits / 2ms / 25KHz = 4.22bps / Hz.

[0089] The data transmission method for discrete narrowband wireless systems provided by this invention has a frame structure length of 10ms, solving the problem that the LTE-G230MHz system cannot meet system design requirements when processing low-latency services due to its excessively long frame structure. The subcarrier spacing of the discrete narrowband wireless system provided by this invention is 2.5kHz, with each carrier containing 7 or 9 subcarriers. The width of 7 subcarriers is 17.5kHz, and the width of 9 subcarriers is 22.5kHz, both less than 25kHz. Therefore, it does not cause changes in the edge subcarrier signals, thus avoiding interference with adjacent subcarriers and overcoming the design deficiencies of the LTE-G230MHz system.

[0090] The peak spectral efficiency of this invention is calculated as follows:

[0091] The system of this invention supports 256QAM modulation with a modulation order of 8.

[0092] The transmission amount within one carrier and one subframe of this invention is as follows:

[0093] When the number of subcarriers is 7 and the number of symbols is 5

[0094] Number of subcarriers * number of symbols * modulation order = 7 * 5 * 8 = 280 bits; peak spectral efficiency = transmission volume / frame length / bandwidth = 280 bits / 2 ms / 25 kHz = 5.6 bps / Hz;

[0095] When the number of subcarriers is 7 and the number of symbols is 6

[0096] Number of subcarriers * number of symbols * modulation order = 7 * 6 * 8 = 336 bits; peak spectral efficiency = transmission volume / frame length / bandwidth = 336 bits / 2ms / 25KHz = 6.72bps / Hz.

[0097] When the number of subcarriers is 9 and the number of symbols is 5

[0098] Number of subcarriers * number of symbols * modulation order = 9 * 5 * 8 = 360 bits; peak spectral efficiency = transmission volume / frame length / bandwidth = 360 bits / 2ms / 25KHz = 7.2bps / Hz;

[0099] When the number of subcarriers is 9 and the number of symbols is 6

[0100] Number of subcarriers * number of symbols * modulation order = 9 * 6 * 8 = 432 bits, peak spectral efficiency = transmission volume / frame length / bandwidth = 432 bits / 2ms / 25KHz = 8.64bps / Hz.

[0101] Table 1 shows a comparison of the peak spectral efficiency of the LTE-G 230MHz system, the IOT-G 230MHz system, and the system of this invention.

[0102]

[0103] Table 1

[0104] The above analysis shows that the spectral efficiency of the LTE-G 230MHz system is 4.64 bps / Hz, and the spectral efficiency of the IOT-G 230MHz system is 4.22 bps / Hz. The minimum spectral efficiency of the system of this invention is 5.6 bps / Hz, which is higher than the spectral efficiency of both the LTE-G 230MHz and IOT-G 230MHz systems in the prior art. Therefore, the data transmission method for discrete narrowband wireless systems provided by this invention significantly improves the peak spectral efficiency compared to existing technologies.

[0105] The uplink and downlink spectral efficiencies of the LTE-G 230MHz system, the IOT-G 230MHz system, and the system of this invention are analyzed in detail below.

[0106] The uplink spectrum efficiency of LTE-G 230MHz is calculated as follows:

[0107] Uplink spectrum efficiency = Uplink data volume / Frame length / Bandwidth * Effective data percentage * Service data percentage;

[0108] Uplink data volume = number of subcarriers * number of symbols in (subframe 2 + subframe 3 + subframe 4 + UpPTS) * modulation order = 11 * (9 + 9 + 9 + 4) * 6 = 2046 bits;

[0109] Calculation of the percentage of valid data:

[0110] The total uplink duration is 2204Ts, and the total CP duration is 64*3+28=220Ts; T S It is the basic unit for taking values ​​in the time domain;

[0111] The percentage of valid data is (2204-220) / 2204 = 90%;

[0112] For service data proportions, uplink control channel overhead is typically taken as 21%, while uplink service data proportion is taken as 79%.

[0113] Therefore, the uplink spectral efficiency = 2046bit / 25ms / 25KHz * 90% * 79% = 2.27bps / Hz.

[0114] The downlink spectrum efficiency of LTE-G 230MHz is calculated as follows:

[0115] Downlink spectrum efficiency = downlink data volume / frame length / bandwidth * effective data ratio * service data ratio;

[0116] Downlink data volume = number of subcarriers * number of symbols in (subframe 0 + DwPTS) * modulation order = 11 * (9 + 4) * 6 = 858 bits;

[0117] Calculation of the percentage of valid data:

[0118] The total duration of downlink (subframe 0 + DwPTS) is 925Ts, and the total duration of CP is 64 + 29 = 93Ts.

[0119] The percentage of valid data is (925-93) / 925 = 90%;

[0120] Service data percentage: Downlink control channel overhead is generally taken as 25%, and downlink service data percentage is taken as 75%.

[0121] Therefore, the downlink spectral efficiency = 858bit / 25ms / 25KHz * 90% * 75% = 0.9bps / Hz.

[0122] The uplink spectral efficiency of the IoT-G 230 system is calculated as follows:

[0123] Uplink data volume = number of subcarriers * number of symbols in (time slot 3 + time slot 4 + UPTS) * modulation order = 6 * (6 + 6 + 3) = 5406 bits;

[0124] Calculation of the percentage of valid data:

[0125] The total uplink duration is 120 + 120 + 60 = 300Ts, and the total CP duration is 24 + 24 + 12 = 60Ts; T S It is the basic unit for taking values ​​in the time domain;

[0126] The percentage of valid data is (300-60) / 300 = 80%;

[0127] Service data percentage: Uplink control channel overhead is typically taken as 21%, while uplink service data percentage is taken as 79%.

[0128] Therefore, the uplink spectral efficiency = 5406bit / 10ms / 25KHz * 90% * 79% = 1.33bps / Hz.

[0129] The downlink spectral efficiency of the IoT-G 230 system is calculated as follows:

[0130] Downlink data volume = number of subcarriers * number of symbols in (slot 0 + slot 1 + DwPTS) * modulation order = 6 * (6 + 6 + 1) = 468 bits;

[0131] Calculation of the percentage of valid data:

[0132] Downlink total duration = 120 + 120 + 20 = 260 Ts, CP total duration = 24 + 24 + 4 = 52 Ts

[0133] The percentage of valid data is (260-52) / 260 = 80%;

[0134] Service data percentage: Downlink control channel overhead is generally taken as 25%, and downlink service data percentage is taken as 75%.

[0135] Therefore, the downlink spectral efficiency = 468bit / 10ms / 25KHz * 80% * 75% = 1.10bps / Hz.

[0136] The uplink spectral efficiency of the system of this invention is calculated as follows:

[0137] Uplink spectrum efficiency = Uplink data volume / Frame length / Bandwidth * Effective data percentage * Service data percentage;

[0138] When the number of subcarriers is 7, the uplink data volume = number of subcarriers * number of symbols in (slot 2 + slot 3) * modulation order = 7 * (6 + 5) * 8 = 616 bits;

[0139] Calculation of the percentage of valid data:

[0140] The total uplink duration is 56832*Tc + 47360*Tc = 104192Tc, and the total CP duration is 11*1280*Tc = 14080Tc; T C The basic unit for the time-domain value of OFDM symbol length;

[0141] The percentage of valid data is (104192-14080) / 104192 = 86.49%;

[0142] Service data percentage: Downlink control channel overhead is generally taken as 25%, and downlink service data percentage is taken as 75%.

[0143] Therefore, when the number of subcarriers is 7, the uplink spectral efficiency = 616bit / 10ms / 25KHz * 86.49% * 75% = 1.598bps / Hz.

[0144] When the number of subcarriers is 9, the uplink data volume = number of subcarriers * number of symbols in (slot 2 + slot 3) * modulation order = 9 * (6 + 5) * 8 = 792 bits;

[0145] Calculation of the percentage of valid data:

[0146] The total uplink duration is 56832*Tc + 47360*Tc = 104192Tc, and the total CP duration is 11*1280*Tc = 14080Tc;

[0147] The percentage of valid data is (104192-14080) / 104192 = 86.49%;

[0148] Service data percentage: Downlink control channel overhead is generally taken as 25%, and downlink service data percentage is taken as 75%.

[0149] Therefore, when the number of subcarriers is 9, the uplink spectral efficiency = 792bit / 10ms / 25KHz * 86.49% * 75% = 2.055bps / Hz.

[0150] Downlink spectral efficiency of the system of this invention:

[0151] Downlink spectrum efficiency = downlink data volume / frame length / bandwidth * effective data ratio * service data ratio;

[0152] When the number of subcarriers is 7, the downlink data volume = number of subcarriers * number of symbols (slot 0 + slot 1) * modulation order = 7 * (5 + 5) * 8 = 560 bits;

[0153] Calculation of the percentage of valid data:

[0154] The total downlink duration is 2 * 47360 * Tc = 94720 Tc, and the total CP duration is 10 * 1280 * Tc = 12800 Tc.

[0155] The percentage of valid data is (94720-12800) / 94720 = 86.49%.

[0156] Service data percentage: Downlink control channel overhead is generally taken as 25%, and downlink service data percentage is taken as 75%.

[0157] Therefore, when the number of subcarriers is 7, the downlink spectral efficiency = 560bit / 10ms / 25KHz * 86.49% * 75% = 1.453bps / Hz.

[0158] When the number of subcarriers is 9, the downlink data volume = number of subcarriers * number of symbols (slot 0 + slot 1) * modulation order = 9 * (5 + 5) * 8 = 720 bits;

[0159] Calculation of the percentage of valid data:

[0160] The total downlink duration is 2 * 47360 * Tc = 94720 Tc, and the total CP duration is 10 * 1280 * Tc = 12800 Tc.

[0161] The percentage of valid data is (94720-12800) / 94720 = 86.49%.

[0162] Service data percentage: Downlink control channel overhead is generally taken as 25%, and downlink service data percentage is taken as 75%.

[0163] Therefore, when the number of subcarriers is 9, the downlink spectral efficiency = 720bit / 10ms / 25KHz * 86.49% * 75% = 1.868bps / Hz.

[0164] Table 2 shows the comparison results of uplink and downlink spectrum efficiency of the LTE-G 230MHz system, the IOT-G 230MHz system, and the system of the present invention.

[0165]

[0166] Table 2

[0167] As shown in Table 2, the uplink and downlink spectral efficiencies of the frame structure designed in this invention are significantly higher than those of existing technologies. Compared to the LTE-G 230MHz system, the uplink spectral efficiency is reduced by approximately 10%, while the downlink spectral efficiency is improved by approximately 107%. The high uplink spectral efficiency of the LTE-G 230MHz system is due to the inclusion of three uplink subframes, carrying more OFDM symbols, but its downlink spectral efficiency is significantly lower. In contrast, the uplink and downlink data ratios in the system of this invention are basically consistent, better meeting service requirements in actual transmission. Compared to the LTE-G 230MHz system, the uplink spectral efficiency is improved by approximately 50%, and the downlink spectral efficiency by approximately 70%.

[0168] The following sections provide a detailed analysis of the overall time-frequency efficiency of the LTE-G 230MHz system, the IOT-G 230MHz system, and the system of this invention, which involves a comprehensive comparison from both the time and frequency domains.

[0169] The frame structure length of the system of this invention is 10ms, the subcarrier spacing is 2.5kHz, and the number of subcarriers in a single carrier is 7 or 9. Each frame includes 21 OFDM symbols. When the number of subcarriers is 7, the overall time-frequency efficiency is 21 * 7 = 147 symbols / 10ms; when the number of subcarriers is 9, the overall time-frequency efficiency is 21 * 9 = 189 symbols / 10ms.

[0170] The LTE-G 230MHz system has a frame length of 25ms, a subcarrier spacing of 2kHz, and 11 subcarriers per carrier. Each frame includes 36 OFDM symbols (9 OFDM symbols per subframe, for a total of 4 subframes). The overall time-frequency efficiency is 36 * 11 = 396 symbols / 25ms, which translates to 158.4 symbols / 10ms. However, due to its 25ms frame length, it is insufficient for low-latency services. When a network problem causes a retransmission, the latency becomes 50ms. Combined with processing latency, this fails to meet the 50ms latency requirement for precise load control services.

[0171] The IOT-G 230MHz system has a frame structure length of 10ms, a subcarrier spacing of 3.75kHz, and a single carrier contains 6 subcarriers. Each frame includes 24 OFDM symbols (6 OFDM symbols per time slot, for a total of 4 time slots). The overall time-frequency efficiency is 24 * 6 = 144 symbols / 10ms. Although the IOT-G 230MHz system has a frame structure length of 10ms...

[0172] Table 3 shows a comparison of the overall time-frequency efficiency of the LTE-G 230MHz system, the IOT-G 230MHz system, and the system of this invention.

[0173] contrast LTE-G 230 IOT-G 230 This invention Subcarrier spacing 2kHz 3.75kHz 2.5kHz Number of subcarriers 11 6 7 / 9 Total number of symbols per frame 36 24 21 Overall time-frequency efficiency 158.4 symbols / 10ms 144 symbols / 10ms 147 symbols / 10ms, 189 symbols / 10ms

[0174] Table 3

[0175] As shown in Table 3, the frame structure designed in this invention, when a single carrier contains 7 subcarriers, achieves an overall time-frequency efficiency comparable to that of LTE-G 230MHz and IOT-G 230MHz systems, while overcoming the design deficiencies in existing technologies. When a single carrier contains 9 subcarriers, the overall time-frequency efficiency of the system is significantly higher than that of LTE-G 230MHz and IOT-G 230MHz systems, while overcoming the design deficiencies in existing technologies. Therefore, the data transmission method for discrete wireless systems designed in this invention can effectively improve the system's transmission capability.

[0176] In addition, the data length of the OFDM symbol in each time slot of the system of this invention is 8192*T. C =8192 * 48.828 ns = 400 μs, CP length is 1280 * T C =1280 * 48.828 ns = 62.5 μs, meaning the CP length ratio for each time slot is 13.5%. Based on the above calculations, the CP length ratio for the LTE-G 230MHz system is 10%, and for the IOT-G 230MHz system it is 20%. The purpose of the cyclic prefix CP design is to reduce inter-symbol interference (ISI) in OFDM caused by the high-order filters required for each 25kHz carrier filter. To overcome this interference, a suitable cyclic prefix and guard interval are needed to ensure that the power of the main interfering signal falls within the cyclic prefix, thereby reducing interference to the effective OFDM signal and enabling high-rate data transmission using high-order modulation. The CP length ratio of the cyclic prefix designed in this invention is between that of LTE-G 230MHz and IOT-G 230MHz, representing a compromise between the two existing methods. It not only reduces ISI interference, thus ensuring high-order modulation, but also allows for a longer time-domain transmission time.

[0177] To address the issues of the long frame length of the LTE-G 230MHz system, which cannot meet the requirements of low-latency service transmission, and the low overall time-frequency efficiency of the IOT-G 230MHz system, this invention provides a data transmission method for a discrete narrowband wireless system. The method involves determining a preset wireless frame structure; the preset wireless frame structure has a frame length of 10ms and includes 4 time slots and 1 guard interval; based on the preset wireless frame structure, the data to be transmitted is transmitted; the discrete narrowband wireless system operates in the frequency band of 223–235MHz, with a single carrier bandwidth of 25kHz and a subcarrier spacing of 2.5kHz. This invention designs a wireless frame structure with a frame length of 10ms, shorter than the 25ms frame structure of LTE-G 230MHz, thus meeting the transmission requirements of low-latency transmission services. The preset frame structure includes 4 time slots and 1 guard interval, improving the effective data transmission time. Furthermore, the cyclic prefix (CP) length of each OFDM symbol is consistent, resulting in low system design complexity. The subcarrier spacing within the carrier is 2.5kHz, shorter than the 3.75kHz subcarrier spacing of IOT-G. The number of subcarriers contained within a single carrier is greater than that of IOT-G 230MHz, significantly improving the overall time-frequency efficiency of data transmission. Simultaneously, the width of the subcarrier width within a single carrier is less than the 25kHz carrier bandwidth, better ensuring the transmission quality of edge subcarriers.

[0178] In summary, the data transmission method for discrete narrowband wireless systems provided by this invention can not only meet the transmission requirements of low-latency services, but also effectively improve the overall time-frequency efficiency of data transmission.

[0179] Example 2:

[0180] Based on the same inventive concept, this invention also provides a communication system, the structural schematic diagram of which is shown below. Figure 7 As shown, it includes a transmitter and a receiver; the transmitter is used to implement the data transmission method of the discrete narrowband wireless system in the above embodiment, and the receiver is used to implement the data transmission method of the discrete narrowband wireless system in the above embodiment.

[0181] Example 3:

[0182] Based on the same inventive concept, the present invention also provides a communication device, the structural schematic diagram of which is shown below. Figure 8 As shown, it includes: a processing module and a communication module.

[0183] The processing module is used to determine the preset radio frame structure; the frame length of the preset radio frame structure is 10ms, and the preset radio frame structure includes 4 time slots and 1 guard interval.

[0184] The communication module is used to transmit data to be transmitted based on a preset wireless frame structure.

[0185] The communication device operates in the frequency band of 223–235 MHz, with a single carrier bandwidth of 25 kHz and a subcarrier spacing of 2.5 kHz.

[0186] Optionally, the four time slots of the preset radio frame structure include: time slot 0, time slot 1, time slot 2, and time slot 3;

[0187] Time slots 0 and 1 form the downlink data transmission time slot, and time slots 2 and 3 form the uplink data transmission time slot. The guard interval (GAP) is used to isolate uplink and downlink data.

[0188] Optionally, the radio frame structure includes 21 orthogonal frequency division multiplexing (OFDM) symbols, each OFDM symbol having a length of 9472*T. C ;

[0189] Time slots 0, 1, and 3 each contain 5 OFDM symbols, and their lengths are 47360*T. C The second time slot includes 6 OFDM symbols, and its length is 56832*T. C ;

[0190] The basic unit for the time-domain value of OFDM symbol length is T. C T C It is 48.828 ns.

[0191] Optionally, the length of an OFDM symbol includes the data length and the cyclic prefix (CP) length, where the data length in the OFDM symbol length is 8192*T. C The CP length is 1280*T C .

[0192] Optionally, when the subcarrier spacing in the carrier is 2.5kHz, the number of subcarriers in the carrier is 7 or 9, and the modulation scheme is 256QAM.

[0193] Optionally, the length of the guard interval (GAP) in the preset wireless frame structure is 287.5 µs.

[0194] Optionally, a superframe consists of 1024 radio frames, with a frame length of 10240ms.

[0195] Example 4:

[0196] Based on the same inventive concept, such as Figure 9As shown, the present invention also provides an electronic device, which may be a computer device, a microcontroller device, a smart mobile device, etc. The electronic device in this embodiment may include a processor, a memory, a transceiver component, etc. The memory, processor, and transceiver component are connected via a bus; the memory can be used to store executable programs, and an exemplary executable program may include instructions; the processor is used to execute the instructions stored in the memory. The memory can also be used to store data, which can be accessed and / or modified when instructions are executed.

[0197] The processor may be a Central Processing Unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and it is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in a readable storage medium to implement the corresponding method flow or corresponding function, so as to realize the steps of the data transmission method of a discrete narrowband wireless system in the above embodiments.

[0198] Example 5:

[0199] Based on the same inventive concept, this invention also provides a readable storage medium, specifically an electronic device readable storage medium (Memory). This readable storage medium is a memory device within an electronic device used to store programs and data. It is understood that the readable storage medium here can include both built-in storage media within the electronic device and extended storage media supported by the electronic device. The storage medium provides storage space, which stores the terminal's operating system. Furthermore, this storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more executable programs (including program code). It should be noted that the storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the storage medium to implement the steps of a data transmission method for a discrete narrowband wireless system in the above embodiments.

[0200] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0201] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0202] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0203] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0204] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the application, but these changes, modifications or equivalent substitutions are all within the scope of protection of the claims pending approval.

Claims

1. A data transmission method for a discrete narrowband wireless system, characterized in that, include: Determine the preset wireless frame structure; The frame length of the preset wireless frame structure is 10ms, and the preset wireless frame structure includes 4 time slots and 1 guard interval; The preset radio frame structure comprises four time slots: time slot 0, time slot 1, time slot 2, and time slot 3. The preset radio frame structure includes 21 Orthogonal Frequency Division Multiplexing (OFDM) symbols. Time slots 0, 1, and 3 each include 5 OFDM symbols, and time slot 2 includes 6 OFDM symbols. The length of each OFDM symbol includes a data length and a cyclic prefix (CP) length, wherein the data length of the OFDM symbol is 8192. The CP length is 1280. ; Based on the preset wireless frame structure, the data to be transmitted is transmitted; The discrete narrowband wireless system operates in the frequency band of 223~235MHz, with a single carrier bandwidth of 25kHz, a subcarrier spacing of 2.5kHz, and the number of subcarriers within the carrier is 7 or 9.

2. The method according to claim 1, characterized in that, The 0th and 1st time slots constitute the downlink data transmission time slots, and the 2nd and 3rd time slots constitute the uplink data transmission time slots. The guard interval (GAP) is used to isolate uplink and downlink data.

3. The method according to claim 2, characterized in that, The length of each OFDM symbol in the wireless frame structure is 9472. ; The lengths of time slot 0, time slot 1, and time slot 3 are 47360 respectively. The length of the second time slot is 56832. ; The basic unit for the time-domain value of the OFDM symbol length is . , It is 48.828 ns.

4. The method according to claim 1, characterized in that, When the subcarrier spacing in the carrier is 2.5 kHz, the modulation scheme of the number of subcarriers in the carrier is 256QAM.

5. The method according to claim 2, characterized in that, The length of the guard interval (GAP) of the preset wireless frame structure is 287.5 μs.

6. The method according to any one of claims 1-5, characterized in that, A superframe consists of 1024 wireless frames, and the frame length of the superframe is 10240ms.

7. A communication device, characterized in that, include: The processing module is used to determine the preset wireless frame structure; The frame length of the preset wireless frame structure is 10ms, and the preset wireless frame structure includes 4 time slots and 1 guard interval; The preset radio frame structure comprises four time slots: time slot 0, time slot 1, time slot 2, and time slot 3. The preset radio frame structure includes 21 Orthogonal Frequency Division Multiplexing (OFDM) symbols. Time slots 0, 1, and 3 each include 5 OFDM symbols, and time slot 2 includes 6 OFDM symbols. The length of each OFDM symbol includes a data length and a cyclic prefix (CP) length, wherein the data length of the OFDM symbol is 8192. The CP length is 1280. ; The communication module is used to transmit the data to be transmitted based on the preset wireless frame structure. The communication device operates in a frequency band of 223~235MHz, has a single carrier bandwidth of 25kHz, a subcarrier spacing of 2.5kHz, and has 7 or 9 subcarriers within the carrier.

8. A data transmission method for a discrete narrowband wireless system, characterized in that, include: Receive a preset radio frame, the frame length of which is 10ms, and the preset radio frame structure includes 4 time slots and 1 guard interval. The preset radio frame structure comprises four time slots: time slot 0, time slot 1, time slot 2, and time slot 3. The preset radio frame structure includes 21 Orthogonal Frequency Division Multiplexing (OFDM) symbols. Time slots 0, 1, and 3 each include 5 OFDM symbols, and time slot 2 includes 6 OFDM symbols. The length of each OFDM symbol includes a data length and a cyclic prefix (CP) length, wherein the data length of the OFDM symbol is 8192. The CP length is 1280. ; Data is obtained from the preset wireless frame; The discrete narrowband wireless system operates in the frequency band of 223~235MHz, with a single carrier bandwidth of 25kHz, a subcarrier spacing of 2.5kHz, and the number of subcarriers within the carrier is 7 or 9.

9. A communication device, characterized in that, include: A communication module is used to receive a preset wireless frame, the frame length of which is 10ms, and the preset wireless frame structure includes 4 time slots and 1 guard interval. The preset radio frame structure comprises four time slots: time slot 0, time slot 1, time slot 2, and time slot 3. The preset radio frame structure includes 21 Orthogonal Frequency Division Multiplexing (OFDM) symbols. Time slots 0, 1, and 3 each include 5 OFDM symbols, and time slot 2 includes 6 OFDM symbols. The length of each OFDM symbol includes a data length and a cyclic prefix (CP) length, wherein the data length of the OFDM symbol is 8192. The CP length is 1280. ; The processing module is used to acquire data from the preset wireless frame; The communication device operates in a frequency band of 223~235MHz, has a single carrier bandwidth of 25kHz, a subcarrier spacing of 2.5kHz, and has 7 or 9 subcarriers within the carrier.

10. A communication system, characterized in that, It includes a transmitter and a receiver; the transmitter is used to implement the data transmission method of the discrete narrowband wireless system according to any one of claims 1-6, and the receiver is used to implement the data transmission method of the discrete narrowband wireless system according to claim 8.

11. An electronic device, characterized in that, include: At least one processor and memory; The memory and processor are connected via a bus; The memory is used to store one or more programs; When the one or more programs are executed by the at least one processor, the data transmission method of the discrete narrowband wireless system as described in any one of claims 1-6 is implemented, or the data transmission method of the discrete narrowband wireless system as described in claim 8 is implemented.

12. A readable storage medium, characterized in that, It contains an executable program, which, when executed, implements the data transmission method of the discrete narrowband wireless system as described in any one of claims 1-6, or implements the data transmission method of the discrete narrowband wireless system as described in claim 8.

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