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Dear all, I have the following two questions if anyone has any insight.
thank you in advance. question 1 : - If all 42
symbols can be used for DL in TDD, without TTG (RX-TX gap) the frame length
will be 4.8 msec (42 * 115.2 usec) instead of 5 msec. Even in that case, the gap
between frame will be RTG only as described above? If so, wouldn’t
it cause the network sync problem? Or, even though all the 42 symbols are used,
there still will be TTG portion in the frame? question 2 : - in
WMAN-OFDMA DL, there are two types of mandatory subchannel allocations, PUSC
& FUSC. In DL PUSC, one slot is defined as ‘2 symbols
& 1 subchannel’ and in DL FUSC, it is defined as ‘1 symbol
& 1 subchannel’. Thus, if ‘No. subchannels’ is indeed
defined as “The no. subchannels parameter indicated the number of
subchannels for a specific allocation” not as per symbol, then I have another question about it. In WMAN-OFDMA
DL_MAP_IE from 802.16-2004/Cor1/D5, the number of subchannels is defined in 6
bits while the number of symbols is defined in 7 bits. The point that I am
confused at with his definition is that the maximum size of burst is limited
with the number of subchannels in FUSC (which is 64 subchannels). In FUSC,
there will be 16 subchannels per one OFDM symbol, thus it means, the max size
of DL burst will take only 4 symbols in total (assuming whole subchannels per
symbol are used for only one user)? To rephrase my question, can I ask
the definition of ‘No. subchannels’ again just to make sure if it
indicate the ‘number of total subchannels within one burst allocation
‘ or it is the ‘number of subchannels per OFDM symbol’? If it
is the ‘number of subchannels per symbol’, then the burst size can
be derived (in # of slots) as (No.subchannels X No. OFDM symbols) in FUSC
and (No. Subchannels X (No. OFDM symbols/2)) in PUSC; or if it the
‘number of subchannels in the DL burst’, the the burst size (in #
of slots) would be N0.subchannels in FUSC with the constraint of N0. OFDM
symbols = No. subchannels and in PUSC with the constraint of No. OFDM symbols =
No. Subchannels/2. thank you in advance regards, Youssef abdelilah |