A novel architecture for IEEE 802.16m subscriber station for joint power saving class management

摘要

IEEE 802.16m amendment is being drafted to meet the 4G network requirements as an extension to 802.16e-2005. In 802.16e, a Subscriber Station (SS) can have multiple connections to a Base Station (BS) for supporting different services simultaneously. SS negotiates sleep-mode with BS by exchange of management information for one or more connections per active Power Saving Class Identifier (PSC_ID) belonging to a Power Saving Class (PSC). However, after this negotiation, SS may not be able to switch to actual sleep-mode (low power operation) as connections belonging to other PSC_ID may be in the transmission or reception mode. Moreover, this causes an overhead of management messages exchanged between the SS and BS per PSC_ID that results in excess packet delay as well as wastage of power and bandwidth. In this paper, we propose a novel architecture referred as Sleep-Mode Manager Architecture to negotiate the sleep mode for the SS and to compute the sleep-mode per quality of service (QoS) class by aggregating the unavailability periods of all the active PSC_ID traffic. This architecture reduces the overhead of management messages, thereby conserving bandwidth and energy as well as supporting dynamic adaptation in sleep-mode parameters. Our simulation and analysis results reveal that the proposed architecture performs substantially better than the 802.16e standard and the relative performance improves with increasing number of active PSC_IDs which can be implemented in 802.16m. Furthermore, through analysis we find that the efficiency of device switching to sleep-mode improves from 7.1% in case of single PSC_ID to 35% in case of joint power class management for ten simultaneous connections. Simulation reveals that, the management message exchange overhead in case of proposed joint power saving class reduces to 1/5th of that in case of individual PSC_ID management in case of four simultaneous PSC_IDs.