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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. |