Inter-LED interference suppression method for reducing code weight

Abstract

The invention discloses an inter-LED interference suppression method capable of reducing code weight. A transmitting end divides a data part in a data frame into a plurality of information blocks, wherein each information block comprises bit information sent by an LED array in parallel at a time; the code weight of the information block is calculated and compared with a preset threshold value, so that the sending state of the information block is determined, and meanwhile, the transmission state is recorded by using a state indication LED; mapping the processed information block to an LED array in an on-off keying mode, and transmitting the information block in an on-off state of an LED; and at a receiving end, identifying the on-off state of each LED in the LED array through image processing, extracting information block data in an image frame, indicating the state of the LED, and judging the transmission state of the information block according to the information of the state indicating LED, so as to restore the data. According to the invention, the problem that the on-off state of the LED is difficult to identify accurately due to mutual interference among the LEDs can be effectively improved, and the transmission rate of data is not reduced at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of visible light camera communication, and in particular to a method for suppressing interference between LEDs by reducing code weight. Background Art

[0002] In visible light camera communication systems, in order to increase the data transmission rate, multiple LEDs are usually used to form an array instead of a single LED, so that multiple bits of information can be transmitted at the same time. However, when using an LED array to communicate with a receiving camera, the following problems are faced: on the one hand, the light of the LED has a certain diffusion angle, which causes the light-emitting areas of adjacent LEDs to overlap, thereby causing mutual interference and affecting the accurate judgment of the LED on and off status; on the other hand, the LED array increases the data transmission rate by transmitting multiple signals in parallel. Although this parallelism increases the rate, it also increases the power consumption per unit time. Therefore, a method is needed that can reduce interference between LEDs and effectively reduce the power consumption of the transmitter without affecting the data transmission rate. Summary of the invention

[0003] The present invention provides a method for suppressing interference between LEDs by reducing code weight to solve the above technical problems. The method can effectively improve the problem that the LED on / off status is difficult to accurately identify due to mutual interference between LEDs, and will not reduce the data transmission rate.

[0004] The solution adopted by the present invention to solve the technical problem is:

[0005] A method for suppressing interference between LEDs by reducing code weight comprises the following steps:

[0006] Step 1, at the transmitting end, divide the data part of the data frame to be sent into multiple information blocks, each of which contains the bit information sent in parallel by the LED array at one time. Before sending, calculate the code weight of the current information block, that is, the number of bits "1" in the information block, and compare it with the preset threshold. Determine the transmission status of the information block (directly send or inverted send) based on the comparison result, and complete the encoding. At the same time, record the transmission status of the information block through the status indicator LED;

[0007] Step 2: At the transmitting end, each information block encoded in step 1 is mapped to the LED array through on-off keying modulation; the bits of each information block are transmitted through the on-off state of the LED array. At the same time, the on-off state of the status indicator LED is transmitted together with the information block;

[0008] Step 3, at the receiving end, the on / off state of each LED in the LED array is identified through image processing, the state of each LED in the current image frame is extracted, and the information block data contained in the image frame and the LED state are obtained;

[0009] Step 4, at the receiving end, the transmission status of the current information block is determined according to the status of the status indicator LED to restore the original data;

[0010] Step 5: At the receiving end, repeat steps 3 and 4 until the data is partially processed, splice all restored information blocks in sequence, generate a complete original data frame and output it.

[0011] Advantages or beneficial effects of the present invention: The present invention provides a method for suppressing interference between LEDs by reducing code weight. By reducing the code weight of the information block to be sent, the problem of overlapping light-emitting areas between adjacent LEDs due to a certain diffusion angle of the LED light, thereby affecting the accurate judgment of the LED on and off state, is effectively improved, thereby improving the reliability of communication; at the same time, the power consumption of the sending end is effectively reduced without affecting the data transmission rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A system diagram of a method for suppressing interference between LEDs by reducing code weight in this embodiment;

[0013] Figure 2 This is a flow chart of a method for suppressing interference between LEDs by reducing code weight according to the present embodiment;

[0014] Figure 3 Flow chart of the method for reducing code weight in this embodiment. DETAILED DESCRIPTION

[0015] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments, examples of which are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0016] Example:

[0017] A method for suppressing interference between LEDs by reducing code weight proposed by the present invention is described below in conjunction with the accompanying drawings.

[0018] First, the transmitting end divides the data part in the data frame into multiple information blocks, each of which contains the bit information sent in parallel by the LED array at one time; then, the code weight of the information block is calculated and compared with the preset threshold to determine the sending status of the information block, and the status indicator LED is used to record the transmission status; next, the processed information block is mapped to the LED array through on-off keying and transmitted in the on-off state of the LED; at the receiving end, the on-off state of each LED in the LED array is identified through image processing, the information block data and the indicator LED status in the image frame are extracted, and the transmission status of the information block is judged according to the information of the status indicator LED, thereby restoring the data.

[0019] In this embodiment, the LED array used is composed of 4×4 independently controllable LED lights, and the spacing between each LED is 3 cm, among which the LED lights in the upper left corner, upper right corner, and lower left corner are always on and used as positioning lights, and the LED in the lower right corner is used to indicate the status of the transmitted information block.

[0020] like Figure 1 As shown, a system block diagram of a method for suppressing interference between LEDs by reducing code weight includes a transmitting end and a receiving end; the transmitting end includes a coding, modulation and LED driving module and an LED lighting module connected in sequence; the receiving end includes a camera, an image processing module, a demodulation and decoding module connected in sequence.

[0021] like Figure 2 As shown, a method for suppressing interference between LEDs by reducing code weight includes the following steps:

[0022] Step 1. At the transmitting end, divide the data part of the data frame to be sent into multiple information blocks, each information block contains 12 bits of information sent by the LED array at one time. Before sending, calculate the code weight of the current information block, that is, the number of bits "1" in the information block, denoted as HW. If the code weight of the information block does not exceed the preset threshold value 6, the original information block is sent directly, and the LED indicating the transmission status is set to "0"; if the code weight of the information block is greater than the preset threshold, each bit in the information block is inverted (that is, "1" becomes "0", "0" becomes "1") and then sent, and the LED indicating the transmission status is set to "1". The specific process is as follows: Figure 3 shown.

[0023] Step 2: At the transmitting end, each information block encoded in step 1 is mapped to the LED array through on-off keying modulation, where bit "1" represents the LED on and bit "0" represents the LED off; the bit of each information block is transmitted through the on-off state of the LED array. At the same time, the on-off state of the status indicator LED is transmitted along with the information block;

[0024] Step 3, at the receiving end, the on / off state of each LED in the LED array is identified through image processing, the state of each LED in the current image frame is extracted, and the information block data contained in the image frame and the LED state are obtained;

[0025] Step 4, at the receiving end, determine whether the current information block has been inverted according to the state of the transmission status indicator LED. If the state is "1", the received information block is inverted bit by bit to restore the original data; if the state is "0", the received information block is directly used as the decoding result;

[0026] Step 5: At the receiving end, repeat steps 3 and 4 until the data is partially processed, splice all restored information blocks in sequence, generate a complete original data frame and output it.

[0027] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for suppressing interference between LEDs by reducing code weight, characterized in that: The method comprises the following steps: Step 1, at the transmitting end, divide the data part of the data frame to be sent into multiple information blocks, each of which contains the bit information sent in parallel by the LED array at one time. Before sending, calculate the code weight of the current information block, that is, the number of bits "1" in the information block, and compare it with the preset threshold. According to the comparison result, determine the transmission status of the information block (direct transmission or inverted transmission), and complete the encoding. At the same time, record the transmission status of the information block through the status indicator LED; Step 2: At the transmitting end, each information block encoded in step 1 is mapped to the LED array through on-off keying modulation; the bits of each information block are transmitted through the on-off state of the LED array. At the same time, the on-off state of the status indicator LED is transmitted together with the information block; Step 3, at the receiving end, the on / off state of each LED in the LED array is identified through image processing, the state of each LED in the current image frame is extracted, and the information block data contained in the image frame and the LED state are obtained; Step 4, at the receiving end, the transmission status of the current information block is determined according to the status of the status indicator LED to restore the original data; Step 5: At the receiving end, repeat steps 3 and 4 until the data is partially processed, splice all restored information blocks in sequence, generate a complete original data frame and output it.

2. The method for suppressing inter-LED interference by reducing code weight according to claim 1, characterized in that: In step 1, the data frame includes a frame header and a data part, wherein the frame header is used for synchronization and the data part contains the data actually required to be transmitted; the code weight represents the number of "1"s in the information block; half of the number of bits contained in the information block is used as the threshold, and the calculated code weight is compared with it, so as to determine the transmission status of the information block and complete the encoding.

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