Enhanced power saving mechanism for supporting multicast services in 802.11 wireless LANs

Traditional 802.11 power saving mechanism (PSM) treats multicast and broadcast traffic equally, and suffers significant performance degradation with multicast background traffic. This paper proposes an enhanced PSM that effectively differentiates multicast streams. It re-arranges the virtual bitmap of the traffic indication map (TIM) to carry traffic status for multicast groups and introduces a concept of sequential transmission of multi-addressed data to facilitate differentiation among multicast groups. Our analysis shows that the enhanced PSM can effectively save power in mixed traffic environments.