r0marvellbss标识符ofdmaframe格式短帧日期.pdfVIP

B entifier • In OFDMA resource allocation (trigger frame SYNC for UL OFDMA or DL HEW PHY SIG for DL OFDMA ), BSS color may be used to identify the AP that transmit the resource allocation. – The overhead of B is too high compared with BSS color although B can provide unique AP identification . – BSS color can use short length, e.g. 7-bit field which provide 128 different BSS identifiers – With BSS color and short frame, wrong frame reception may occur. • Without STA’shelp, each AP needs to select a BSS color that is not used by its neighbor APs. – However s e an AP and its associated STAs have different coverage, STAs may receives resource allocation information and misunderstand the real AP. STA1 STA2 AP1 AP2 Color = 1 Color = 1 STA’sReport of its Detected AP Colors • A STA reports neighboring BSS colors and neighboring B to its associated AP. – The BSS colors that are reported by STAs and detected by the AP are defined as the occupied BSS color set. • When a STA detects a neighboring BSS color that is same as its BSS, the STA reports the collided color event and the neighboring B . • When the BSS color is distributively selected by each AP, – The AP randomly selects a new BSS color which is not in the occupied BSS color set if its associated STA reports a collided BSS color event. • To avoid simultaneously color changing, a delay changing per backoff may be used with beacon interval as backoff slot. – When the STA that detects collided color receives a new color