Dynamic multi-rate parallel transmission for power saving of stations in wireless LAN multicast

Recently, multicast transmission in wireless LAN is increasing. On the other hand, due to wide diffusion of smartphones and tablet computers as well as laptop ones, electric power saving of STAs (wireless stations) becomes more important. However, when a few STAs which can use only a low transmission rate exist in multicast group, the AP (Access Point) needs to transmit packets to all STAs at the low rate. As a result, the power consumption of all the STAs extremely increases by extending operating period of transceiver. In this paper, to reduce total power consumption of STAs in multicast group, we propose multi-rate parallel transmission where packets are transmitted multiple times at high and low rates. This reduces power consumption of STAs on which a high transmission rate is available because packet reception at the high rate decreases operating period of transceiver and sleep period can be inserted. In other words, power consumption required for packet communication processing itself is reduced. This differs from existing power saving method in which STAs sleep only when there are no packets to communicate. Finally, we show the effectiveness of the proposed method by computer simulation.