Method and device for dividing and selecting random time slot for multi-channel variable time window in real time

A multi-channel, time-slot technology, applied in digital transmission systems, electrical components, error prevention, etc., can solve the problems of inability to transmit messages, low system real-time processing, and insufficient real-time processing.

Active Publication Date: 2015-04-01

四川九洲空管科技有限责任公司

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AI-Extracted Technical Summary

Problems solved by technology

[0005] 2. The real-time processing of the system is not high, and the real-time processing is not enough, which will lead to the arrival of the message that needs to be transmitted, but the time...

Method used

Step 1032, obtain the configuration initial value FIS_set_gateway1~FIS_set_gateway8 and channel enabling signal of FIS-B message transmission channel from CPU commun...

Abstract

The invention belongs to the field of message processing, and in particular relates to a method and a device for dividing and selecting a random time slot in real time. To solve the problem in the prior art, the invention provides a method and a device for dividing and selecting a random time slot in real time. According to the invention, the type and the amount of a message are transmitted as required; transmission time channels and transmission time slots are established for message of different types in combination with pulse per second, so that the working efficiency of the system is improved. The method comprises the following steps: firstly, dividing time periods for transmitting an FIS-B (Flight Information Service-Broadcast) message and a TIS-B (Traffic Information Service-Broadcast) message according to pulse per second, obtaining the initial configuration value of an FIS-B message transmission channel according to a CPU (Central Processing Unit) communication interface, and determining a specific FIS-B message transmission channel; secondly, obtaining the initial configuration value of an offset of a TIS-B message transmission time window according to the CPU communication interface, setting the TIS-B message transmission time window, and further dividing the TIS-B message transmission time window; finally, updating the message transmission channel and the time slot according to pulse per second.

Application Domain

Error preventionData switching networks

Technology Topic

Communication interfaceTraffic information service – broadcast +8

Image

Examples

Experimental program(8)

Example Embodiment

[0058] Example 1:

[0059] refer to figure 1 shown,

[0060] 1. 1s is divided into FIS-B time period and TIS-B time period. The length of the entire FIS-B time period is 200ms, and the length of the entire TIS-B time period is 800ms. -start=Tkeep-end=6ms), there is 188ms left in the FIS-B period (TFIS), and 788ms in the TIS-B period (TTIS).

[0061] Among them, the signal characteristics of FIS-B: 32+8*6*9232, a total of 4448 bits, each bit takes 960ns, and it takes 4270080ns, about 4.3ms, to transmit a complete message. The length of the entire FIS-B period is 200ms, and after removing the guard time interval at the beginning and the end, there is only a time of 188ms (TFIS). The TFIS is divided into 32 channels on average, and the time of each channel is about 5.8ms, which is enough to transmit a complete FIS-B message. The system can transmit up to 8 FIS-B packets per second, so configure 8 channels out of 32 channels and enable the corresponding channels.

[0062] Among them, the signal characteristics of TIS-B: there are two kinds of messages, which are 32+8*48=416 bits and 32+8*30=272 bits. It is not known which message is transmitted at any time, so only It can be set according to the kind of long message. That is, 416*960=399360ns, about 400us time. The length of the entire TIS-B time period is 800ms, and after removing the guard time interval at the beginning and the end, there is only a time of 788ms (TTIS). The TTIS is divided into five time windows with a width of 19ms, (T1start~T1end, T2start~T2end, T3start~T3end, T3start~T3end, T5start~T5end). Each time window of 19ms is further divided into 76 time slots according to the interval of 250us, and even numbers are selected as intervals. The transmission time of each message is set to 250*2=500us, which is enough to transmit a complete TIS-B message. The system can transmit up to 190 TIS-B messages per second, and one time window can transmit up to 76/2=38 messages, and 5 time windows can transmit a total of 38*5=190 messages. time slots can be divided.

[0063] 2. The CPU communication interface refers to the port that sends commands to the control device of the system.

[0064] As an important surveillance technology in the navigation system, ADS-B can be used as an effective supplement to radar surveillance in the radar coverage area to calibrate or compensate for radar surveillance; in the non-radar coverage area, it can be used as an independent surveillance technology to provide New means of surveillance. During specific implementation, an ADS-B system needs to have the ability to randomly transmit 8 FIS-B packets and 190 TIS-B packets per second, and it needs to divide the transmission time of FIS-B packets and TIS-B packets within 1s. The transmission time of the FIS-B message in each second is constantly changing in the 32 transmission channels, and the transmission time of the TIS-B message is continuously in 380 time slots divided in 5 continuously offset time windows. Variety. The way of dividing the transmission time slot of the specific message is very complicated, and it is updated and changed every second. The system's time slot division method and specific implementation method have high requirements.

Example Embodiment

[0065] Example 1:

[0066] Step 1: Delineate the transmission time period of the FIS-B message and the TIS-B message according to the second pulse; figure 1 Provided for the present invention is a method for real-time division and selection of random time slots with multi-channel variable time windows. figure 1 As shown, the time period is divided as follows: The specific method is: take the second pulse as the starting point, set the initial Tkeep_start as the start protection time of FIS-B message transmission, and then TFIS is the FIS-B message transmission time period, which can be used in this time period A maximum of 8 FIS-B messages are transmitted within the system. Next, Tkeep_end is the protection time for the termination of FIS-B message transmission, and Tkeep_start is set as the start protection time for the transmission of TIS-B messages. Then TTIS is the TIS-B message transmission start protection time. In the transmission time period, a maximum of 190 TIS-B messages can be transmitted within this time period, and then Tkeep_end is the termination protection time for the transmission of TIS-B messages.

[0067] Step 2: During the FIS-B message transmission time period, obtain the initial configuration value of the FIS-B message transmission channel according to the CPU communication interface, delineate a specific FIS-B message transmission channel, and perform step 4; During the TIS-B message transmission time period, obtain the initial configuration value of the TIS-B message transmission time window offset according to the CPU communication interface, and perform step 3;

[0068] Step 3: According to the initial configuration value of the TIS-B message transmission time window offset, set the TIS-B message transmission time window, and specifically subdivide the TIS-B message transmission time slot, and perform step 4:

[0069] Step 4: the message interface obtains the message, and judges whether it is a FIS-B message or a TIS-B message according to the message synchronization header flag, and if it is a FIS-B message, transmits the FIS-B message according to an effective transmission channel; If it is a TIS-B message, the TIS-B message is transmitted according to the transmission time gap; otherwise, the message is discarded;

[0070] Step 5: When the next second pulse arrives, update the FIS-B message transmission channel and the TIS-B message transmission time slot, and return to step 4.

Example Embodiment

[0071] Embodiment 2: figure 2 for figure 1 The schematic flowchart of delineating a specific FIS-B packet transmission channel according to the obtained configuration initial value in step 2 of the first embodiment shown, including:

[0072] Step 1031: Divide the FIS-B time period into 32 channels FIS_gateway1 to FIS_gateway32 that can transmit packets, namely T FIS The transmission time period of the FIS-B message is ΔT FIS For stepping, it is divided into 32 channels that can transmit messages;

[0073] Step 1032: Obtain the initial configuration value FIS_set_gateway1~FIS_set_gateway8 and the channel enable signal of the FIS-B message transmission channel from the CPU communication interface, configure a maximum of 8 transmission channels, that is, obtain FIS_set_gateway1, FIS_set_gateway2...FIS_set_gateway8, the enable signal is high and effective;

[0074]Step 1033: Correspond the configured FIS_set_gateway to the specific channel in the divided FIS_gateway1 to FIS_gateway32, and determine whether the channel enable is valid, if the enable signal is valid (equal to 1), go to step 1034, if invalid (equal to 0), then not configured;

[0075] Step 1034: Use the corresponding FIS_set_gateway in FIS_gateway1 to FIS_gateway32 as a valid FIS-B message transmission channel, and set the corresponding time flag to 1.

PUM

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