Patent ID: 8184568

Claim:
A wireless local area network (LAN) system comprising: a base station of a wireless LAN, being connected to a LAN terminal; and a plurality of wireless terminals connected to the base station, wherein each of the wireless terminals comprises: means for executing a sleep mode in which the wireless terminal operates with low power, means for notifying the base station of a broadcast/multicast (BC/MC) address for receiving data from the base station by BC/MC communication when said wireless terminal executes a program using the BC/MC communication in the wireless LAN, means for switching the sleep mode to an awake mode and recognizing whether unicast data to be addressed to said wireless terminal by unicast communication is accumulated by the base station, means for switching the awake mode to the sleep mode if the unicast data is not accumulated by the base station, and means for notifying the base station of the switching to the awake mode from the sleep mode if the unicast data is accumulated by the base station; and the base station comprises: means for registering a BC/MC address notified from a wireless terminal of the plurality of wireless terminals as information related to a unicast address of the wireless terminal, means for converting BC/MC data addressed to the wireless terminal and received from the LAN terminal into unicast data by rewriting a BC/MC address of the received BC/MC data as the unicast address related to the registered BC/MC address that is the same as the received BC/MC address, means for sending information indicating that the unicast data is accumulated by the base station to the wireless terminal, means for transmitting the unicast data to the wireless terminal which has notified the base station of the switching to the awake mode from the sleep mode, means for sending out a Traffic Indication Map (TIM) beacon and a delivery TIM (DTIM) beacon based on IEEE802.11 to the wireless LAN, wherein transmission timing of the unicast data is related to transmission timing of the TIM beacon and not related to transmission timing of the DTIM beacon, and means for determining whether a wireless terminal is in the sleep mode or the awake mode, and sending out the BC/MC data to the wireless LAN without changing a destination address if none of the plurality of wireless terminals is in the sleep mode.