مشخصات پژوهش

Background and Objectives: The combination of multiple-input-multiple-output (MIMO) with a Visible light communication (VLC) system leads to a higher speed of data transmission named the MIMO-VLC system. In multi-user (MU) MIMO-VLC, an LED array transmits signals to users. These signals are categorized as signals of private information for each user and signals of public information for all users. Methods: In this research, we design an omnidirectional precoding to transmit the signals of public information in the MU-MIMO-VLC network. We aim to maximize the achievable rate which leads to maximizing the received mean power at the possible location of the users. Besides maximizing the achievable rate, we consider equal mean transmission power constraints in all LEDs to achieve higher power efficiency of the power amplifiers used in the LED array. Based on this, we formulate an optimization problem in which the constraint is in the form of a manifold, and utilize a gradient method projected on the manifold to solve the problem. Results: Simulation results indicate that the proposed omnidirectional precoding can achieve superior received mean power besides more than 10x bit error rate reduction compared to the classical form without precoding utilization. Conclusion: In this research, we proposed an omnidirectional precoding for transmitting the public signals in the MU-MIMO-VLC system. The proposed optimization problem maximizes the received mean power constrained with equal transmission mean power of LEDs in the array.