Visible Light Positioning And Communication Cooperative Systems Based On ACO-OFDM

Visible light positioning technology as a new indoor positioning method has attracted wide attention for its advantages of no electromagnetic interference,no spectrum authentication and high positioning accuracy.However,a long-term difficulty has been existing: the separation of communication and positioning technology.And the positioning accuracy is easily affected by multi-path effect,which results in large positioning error.In order to reduce the influence of multipath interference on the positioning accuracy in the indoor visible light positioning,a shceme of visible light positioning and communication cooperative system based on ACO-OFDM is proposed.The scheme can satisfy the dual requirements of location and communication,and improve the anti-multipath interference ability of the system.In this paper,the principle of ACO-OFDM and DCO-OFDM are firstly studied.Then,the ACO-OFDM is compared with DCO-OFDM from aspects of energy saving,anti-subcarrier interference ability,and the degree of influence by the non-linear effect of LED.It is concluded that ACO-OFDM technology has more advantages in indoor positioning and communication cooperative system.Then,the indoor illumination distribution and channel model under the three-lamp positioning model are analyzed.It explains the details of the subcarrier allocation principle,system design principle and system block diagram in the visible light positioning and communication cooperative system based on ACO-OFDM.The simulation results show that the average positioning error of the cooperative system is 19.8 cm at 20 dB signal-to-noise ratio,which basically satisfy the indoor positioning requirements.Finally,To solve the problem of large positioning error at indoor edge,a weighted centroid algorithm combined with strong signal selection based on RSSI is proposed.Simulation results verify that the average positioning error of the cooperative system is reduced by 2.3 cm under the improved algorithm.To conclude,the proposed scheme improves the positioning accuracy of the edge.