The basic feature of the emerging high throughput IEEE 802.11n standard (and other standards) is the presence of directional antennas at network nodes. In this work, we evaluate the performance of media access control protocols in such envisioned IEEE 802.11n wireless LANs that operate in point coordination function (PCF) mode. The access point (AP) is equipped with an adaptive antenna array. In this work, we present two schemes for coping with such mobility scenarios in order to alleviate the potentially large delays that are anticipated in user mobility scenarios. The first scheme is based on location caching at the AP, namely maintaining the most recent location of each user at a cache memory at the AP, so that in a future time the AP selects an appropriate sector to start the search from. The second alternative indirectly attempts to reduce the required time by employing multiple transceivers. Numerical results show significant performance benefits for these two schemes.

Peer Reviewed