Research And Verification Of Indoor Visible Light Positioning Method Based On PoE Lighting

The realization of the dual carbon goal driven by the digital economy and the improvement of the operational quality of the digital economy with the dual carbon as the focus are the main sustainable development directions proposed by the National Two Sessions.Indoor is the main place where the core participants of economic activities and information flow are concentrated,and electricity usage in buildings makes up 26% of overall electricity generation,with lighting contributing to 60% of that consumption.An integrated architecture based on Power over Ethernet(Po E),information exchange,Light Emitting Diode(LED)lighting,and perceptual communication will form a new type of intelligent building,which can further significantly decrease energy usage in buildings,comprehensive wiring,and reconstruction costs,and improve comfort.Among them,indoor positioning based on Po E lighting is a key part,but there is no targeted research at present.Based on the IEEE 802.3bt Po E standard,this thesis proposes a positioning beacon and positioning model that combines Po E lighting and positioning,as follows:First,On-Off Keying(OOK)is the most economical LED modulation method,which can directly utilize the Po E dimming circuit,but there are limitations such as switching speed,response time and synchronization between nodes,resulting in poor positioning accuracy.To this end,this thesis proposes an indoor beacon construction method based on OOK coded pulse pairs and the corresponding asynchronous positioning model,which can obtain the best position estimation under the maximum a posteriori probability criterion without the need for dedicated networking and synchronization protocols.Secondly,utilize the compatibility of OOK and Po E lighting to achieve low-cost,high-precision positioning.Under the hardware architecture of Po E lighting,the signal is transmitted from the LED to the terminal,there will be multiple errors in this process,including the error between Po E-LED synchronization and the error in the signal transmission process.In order to reduce the cost of positioning a single LED indoors and maintain accuracy,a method of recovering pulses with a high sampling rate using pulse reconstruction at a low sampling rate is proposed,and a Po E-LED positioning model is constructed.Thirdly,after semi physical verification,it is shown that: in an indoor environment of 5 m × 5 m × 3 m,under a bandwidth of 200 MHz and a sampling rate of 1 GHz,the probability of positioning error less than 8.2 mm is 90% when the Signal-to-Noise Ratio(SNR)is 50 d B.In the same scenario,the hardware bandwidth is constrained to50 MHz,when the SNR is 50 d B,simulation is conducted based on measured data at a sampling rate of 100 MHz,the improved low sampling rate positioning method in this thesis can achieve a positioning accuracy of 1.7 cm with a probability of 90%;when the SNR is 30 d B,a positioning accuracy of 4.7 cm can be achieved with a 90%probability.Hence,the positioning method proposed in this thesis can optimize the positioning performance based on OOK positioning,and the low-cost positioning method for Po E lighting can solve the problem of large representation error of received pulse arrival time measurement results,so that the proposed method can still maintain good positioning performance under low sampling rate and low bandwidth.Theoretical analysis and semi physical verification show that the indoor visible light positioning method based on Po E lighting proposed in this thesis achieves lowcost integration of lighting positioning.Under the conditions of 100 MHz sampling rate and 50 MHz bandwidth,when the SNR is within the range of 30 d B,the terminal can achieve a positioning accuracy of 4.7 cm with a 90% probability,which has good theoretical value and engineering application value.