[STDS-802-16-MOBILE] Clarification of ID's
Dear all:
How are you?
I think there are lots of confusions on various ID's and their hierarchy/relationship.
Here is what I think. Note that the hierarchy is given in the order of appearance given in the following.
BS-ID (48 bits) : only specifies the BS even though it has multiple FA and multiple sectors.
Hence, if only BS ID is specified, the BS itself is identified, not a specific sector in a certain FA.
FA ID (8 bits): As mentioned during the conference call, FA ID means the channel index or number that would be defined by the service provider.
Sector ID (8 bits by preamble index): After specifying the BS ID and FA ID, we still have to specify which sector the traffic or data is directed to. As we said, maybe only 2 bits (or 3 bits if 6 sector BS) are enough to specify one sector of a BS. However, in the standard, the network never specifies the preamble index that the neighboring sector/BS uses, which delays the synchronization time in scanning or HO. Hence, although the overhead employing the preamble index instead of sector ID is a little higher, the preamble index as sector ID gives more benefits compared to the added overhead.
Note that if a BS has only one FA, then FA ID is not necessary since already Physical Center Frequency is given in the MOB-NBR-ADV message.
One more note is that it seems the sector ID should be listed for each FA. However, in the different FA, the reuse of the same preamble index doesn't make any confusion. So, just listing FA ID and Preamble Index in MOB-NBR-ADV message is enough to specify all the FA and sector combination.
In conclusion, if there is a BS which as multiple FA and sectors, to specify a sector in a certain FA, we require 64 bits (48 bits for BS ID + 8 bits for FA ID + 8 bits for sector ID/preamble index).
I hope this email helps all the members understand the hierarchy and the relationships of ID's.
Regards,
Jung-Won Kim, Ph. D.