A table-driven time slot control method

Abstract

The present invention provides a table-driven time slot control method, which configures a time slot table. Each element in the time slot table includes time slot block length information and time slot type information respectively. After the node receives a time slot interruption, it calculates the time slot number of the next time slot according to the current system time. After obtaining the time slot block length information and time slot type information of the next time slot by querying the time slot table, it configures the corresponding signal data for the next time slot. When the next time slot arrives, it sends the configured signal data. The present invention designs a 64×1536 time slot table, obtains the time slot number of the next time slot in advance when receiving a time slot interruption, and obtains the time slot status of the next time slot by looking up the table, calculates relevant data according to the block length and time slot type, has the advantages of high efficiency, small memory occupancy and flexible control, efficiently realizes the time slot control function of the data link for the airborne platform, and improves the service flexibility of the data link for the airborne platform.

Description

Technical Field

[0001] The present invention relates to the field of ultra-short wave communication, and particularly relates to a table-driven time slot control method. Background Art

[0002] The data link to-air station is an ultra-short wave communication device used for communication between a ground tower and an aircraft. Multiple nodes can form a wireless communication network. There is a problem of channel access control in the wireless communication network. The commonly used MAC layer protocols include two methods: CSMA (Carrier Sense Multiple Access) and TDMA (Time Division Multiple Access). Since CSMA cannot guarantee the time of channel access and the access collision will cause a significant decline in network performance when the number of nodes is large, the TDMA networking method is generally adopted.

[0003] In a TDMA network, time is divided into periodic time elements, time frames, and time slots. According to a certain time slot allocation principle, one or more time slots are allocated to each node (the base station in the TDMA network), and each node sends corresponding data in the specified time slot. The existing allocation control methods are inefficient and cannot meet the requirements of TDMA network communication. Summary of the Invention

[0004] In order to solve the problems existing in the background art, the present invention proposes a table-driven time slot control method.

[0005] A table-driven time slot control method configures a time slot table. Each element in the time slot table includes time slot block length information and time slot type information respectively; after the node receives a time slot interruption, the time slot number of the next time slot is calculated according to the current system time; after obtaining the time slot block length information and time slot type information of the next time slot by querying the time slot table, the corresponding signal data is configured for the next time slot; when the next time slot arrives, the configured signal data is sent.

[0006] Based on the above, time is expressed by time elements, time frames, and time slots, and the time slot table is configured according to time elements; wherein, the unit time second is divided into 128 time slots, then:

[0007] 1 time slot = 7.8125 ms;

[0008] 1 time frame = 12 s = 1536 time slots;

[0009] 1 time element = 12.8 min = 64 time frames = 98304 time slots;

[0010] 1 day = 112.5 time elements = 7200 time frames = 11059200 time slots;

[0011] The time slot number corresponding to 00:00:00 in the target time zone is No. 0.

[0012] Based on the above, each time slot in the time slot table is represented by eight-bit binary. The upper four bits represent the time slot block length information of the time slot, and the lower four bits represent the time slot type information.

[0013] Based on the above, the time slot types include access time slot, network management time slot, data time slot, voice time slot and receive time slot. Among them, the access time slot is used to send time synchronization messages; the network management time slot is used to send network management messages; the data time slot is used to send data information; the voice time slot is used to send voice information; the receive time slot is used as the receive time slot of the receiving end to receive information sent by other sites.

[0014] Based on the above, the time slots of each time frame are divided into Group A, Group B and Group C respectively, and the time slots of Group A, Group B and Group C are alternately distributed.

[0015] Based on the above, multiple consecutive time slots are cascaded into a time slot block; the block length represents the number of continuously cascaded time slots, with a maximum of 15.

[0016] Based on the above, the representation method of time slot allocation is time slot group - starting time slot - repetition rate - block length. Among them, time slot group - starting time slot - repetition rate represents the number of time slots allocated in a time element and the allocated interval time period, and the block length represents the time length occupied by this time slot unit.

[0017] Based on the above, in the time slot table, the time slot type is configured with a corresponding distinguishing color.

[0018] The present invention has prominent substantial features and remarkable progress compared with the prior art. Specifically, the present invention divides the time slot types and designs a 64×1536 time slot table. When receiving a time slot interruption, it obtains the time slot number of the next time slot in advance, and obtains the time slot status of the next time slot by looking up the table. It allocates relevant signal data according to the block length and time slot type, and completes the control and management of tasks such as access synchronization, network management, data transmission, voice transmission, and hopping frequency calculation. It has the advantages of high control efficiency, moderate memory occupancy, and flexible control method, efficiently realizes the time slot control function of the data link to the airborne station, and greatly improves the service flexibility of the data link to the airborne station. Description of the Drawings

[0019] Figure 1 It is a system block diagram of the data link to the airborne station in the prior art of the present invention;

[0020] Figure 2 It is a schematic diagram of the time frame structure of the present invention;

[0021] Figure 3 It is a flow chart of the time slot table setting of the present invention;

[0022] Figure 4 Schematic diagram of time slots of the present invention;

[0023] Figure 5 Flow chart of time slot interruption processing of the present invention. Detailed implementation manners

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] In reality, as Figure 1 shown, the data link air platform includes a host unit and a radio frequency front end. The PL (programmable logic) end provides a time slot interruption (period 7.8125 ms). To ensure the accuracy of the periodic time slot interruption, a high-precision external temperature-compensated crystal oscillator (50 MHz) is used as the clock source of the main control module (model FMQL45T900). The PL end generates a 100 MHz clock after frequency multiplication and provides a time slot interruption with an error within 10 ns to the PS (processing system) end.

[0026] The time slot interruption processing process is as Figure 5 shown. When the PS end of the main control module receives a time slot interruption, the PS end will calculate the time slot number of the next time slot according to the current system time (reserving data processing time for the modulation and demodulation module, preparing the transmission and reception parameters in advance, and filling the signal data to be transmitted), calculate the row number and column number of the next time slot in the time slot table according to the time slot number (the time slot number is first modulo 98304 to obtain the number of time slots within a time element, the number of time slots is divided by 1536 to obtain the row number, and the number of time slots is modulo 1536 to obtain the column number), obtain the block length and time slot type information of the time slot corresponding to the next time slot number by looking up the table, fill the signal data to be transmitted according to the block length and time slot type (in reality, generally, the signal data of tasks such as network entry synchronization and network management is in a blocked waiting state) to the modulation and demodulation module. After the modulation and demodulation module finishes data processing, it will send the data to be transmitted when the next time slot arrives, and complete the control and management of tasks such as network entry synchronization, network management, data transmission, voice transmission, and hopping frequency calculation (receiving state).

[0027] Specifically, the unit of time "second" is divided into 128 time slots, and the duration of each time slot is 7.8125 ms. There are a total of 11,059,200 time slots in 24 hours a day. Taking 00:00:00 in the target time zone, such as Beijing time, as the time slot number 0, each time slot is sequentially calculated and assigned a time slot number. The time slot number corresponding to the current time can be calculated. For example, for Beijing time 17:07:10, the calculation method of the current time corresponding to the time slot number () is as follows:

[0028] In this embodiment, time is expressed in the way of time element, time frame, and time slot. The specific time division is as follows:

[0029] 1 time slot = 7.8125 ms;

[0030] 1 time frame = 12 s = 1536 time slots;

[0031] 1 time element = 12.8 min = 64 time frames = 98,304 time slots;

[0032] 1 day = 112.5 time elements = 7200 time frames = 11,059,200 time slots.

[0033] As Figure 2 shown, the 1536 time slots of each time frame are divided into three groups A, B, and C, and each group includes 512 time slots. The time slots of groups A, B, and C appear in an alternating manner. The sorting order of the time slots within one time frame is A-0, B-0, C-0, A-1, B-1, C-1,... A-511, B-511, C-511.

[0034] The time slot allocation adopts the representation method of time slot group - starting time slot - repetition rate - block length, such as A-3-10-3. The time slot group - starting time slot - repetition rate represents the number of time slots allocated in one time element and the time interval period of allocation, and the block length represents the time length occupied by this time slot unit. For example, A-3-10-3 means starting from time slot 9, the repetition rate of 10 means it appears once every 96 time slots, and the block length of 3 means it occupies 3 consecutive cascaded time slots each time (3 * 7.8125 ms). In this embodiment, the repetition rate is 0 - 15, and the number of time slots and time intervals under different repetition rates are shown in Table 1:

[0035] Table 1

[0036] Configure a time slot table of 64×1536 in accordance with time elements. Each time slot in the time slot table is represented by an eight-bit binary number, occupying 1 Byte (byte), and a total of 98304 Byte of memory is occupied (the system has a total of 512 MB of memory). The high four bits of each byte represent the time slot block length information of the time slot, and the low four bits represent the time slot type information. Different time slot types are represented by different colors. Taking A-0-9-3 (access time slot, blue), A-1-10-3 (network management time slot, yellow), A-3-10-12 (data time slot, red), A-8-11-3 (voice time slot, green) as examples (the receive time slot is colorless or white), the time slot table after setting is as Figure 4 shown. By setting different colors, it is convenient for the staff to visually observe the time slot type when intervening in the operation.

[0037] Under the condition of TDMA network time synchronization, according to the system time, obtain the time slot block length and time slot type of the next time slot through the look-up table method. The time slot block length information is used to control the size of the transmitted data volume, and the time slot type information is used to control and manage tasks such as access synchronization, network management, data transmission, voice transmission, and hopping frequency calculation (receive state). The access time slot is mainly used to send inter-site time synchronization messages to maintain the time between sites to ensure normal communication between sites; after time synchronization is completed, communication between sites is essential, and the role used for site maintenance and management is called the network management station. The network management time slot realizes the control of the site by sending management and maintenance-related information through the network management station. The network management station issues management and maintenance information according to the actual requirements of the task in the network management time slot; after time synchronization is achieved between sites, service communication can be carried out. The data time slot will be used as the time slot for the site to conduct data communication. When the site has data to transmit, the site will process the data to be transmitted in the previous time slot of the data time slot and send it when the data time slot arrives; similarly, the voice time slot is used to transmit voice messages; other time slots without services to be processed are set as receive time slots. The receive time slot serves as the receive time slot of the receiving end, calculates the receive frequency, and is used to receive information sent by other sites.

[0038] To meet the data transmission requirements of different traffic volumes, the method of time slot concatenation is used to control the size of the data transmission volume, that is, multiple continuously concatenated time slots are used as a time slot block, and the number of consecutive time slots used as the transmission time slot for this type of data is determined according to the length of the time slot block. In the initial state, the time slot table is defaulted to all receive time slots. According to the size of the transmitted data volume, select an appropriate time slot block length to control the data transmission volume. The maximum time slot block length for a single transmission is 15.

[0039] There are two methods for setting the time slot table. One is to issue a time slot control instruction through the local host unit, which is transmitted through the optical fiber link to the PL end of the main control module. Then, the data on the optical fiber interface at the PL end of the main control module is forwarded to the PS end through the internal AXI bus for parsing. The PS end extracts the time slot configuration information to set the time slot table. The other is through the network control message sent by the remote network management station, using a wireless method, through the modulation and demodulation module to the PS end. The PS end extracts the time slot configuration information to set the time slot table.

[0040] When setting the time slot table, according to the time slot group - start time slot - repetition rate - time slot block length information parsed by the PS end from the message, first, the legality of the time slot group, block length, etc. is judged. After the judgment is legal, the new time slot information is written into the time slot table. When the new time slot information is written into the time slot table, it will overwrite the original time slot information. Each time slot in the time slot table is represented by 1 byte. The upper four bits store the block length, and the lower four bits are used to store the time slot type. The setting process is as Figure 3 described.

[0041] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed within the present invention. Any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. A table-driven time slot control method, characterized in that: Configure a time slot table, and each element in the time slot table includes time slot block length information and time slot type information respectively; After the node receives a time slot interruption, calculate the time slot number of the next time slot according to the current system time; Obtain the time slot status of the next time slot, that is, the time slot block length information and the time slot type information, by querying the time slot table, and then configure the corresponding signal data for the next time slot according to the time slot status to realize the control and management of the corresponding time slot task; When the next time slot arrives, send the configured signal data.

2. The table-driven time slot control method according to claim 1, wherein: Each time slot in the time slot table is represented by an eight-bit binary number, and the high four bits represent the time slot block length information of the time slot, and the low four bits represent the time slot type information.

3. The table-driven time slot control method according to claim 1, wherein: The time slot types include access time slots, network management time slots, data time slots, voice time slots, and receive time slots; among them, the access time slots are used to send time synchronization messages; the network management time slots are used to send network management messages; the data time slots are used to send data information; the voice time slots are used to send voice-like information; the receive time slots are used as the receive time slots of the receiving end to receive information sent from other stations.

4. The table-driven time slot control method according to claim 1, wherein: Multiple consecutive time slots are cascaded into a time slot block; the block length represents the number of consecutive cascaded time slots, with a maximum of 15.

5. The table-driven time slot control method according to claim 1, wherein: The representation method of time slot allocation is time slot group - start time slot - repetition rate - block length; where time slot group - start time slot - repetition rate represents the number of time slots allocated in a time element and the allocated interval time period, and the block length represents the time length occupied by this time slot unit.

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