Optical signaling has added a new dimension to contemporary wireless sensor network (WSN) as a green and energy efficient technology. Optical wireless communication is considered to replace radio frequency in future sensor network. In fact, Optical wireless communication using visible light has become a benchmark technology in order to improve the speed and robustness of the communication link in indoor wireless sensor network and considered to be featured heavily in future sensor network. In this paper, we propose a novel resource allocation for visible light based WSN. We propose joint power allocation and bandwidth allocation for downlink transmission. Then we propose admission control to guarantee quality of service (QoS) in order to maintain service requirement. The simulation result shows satisfactory performance improvement.