[STDS-802-16-MOBILE] Downlink FUSC data subcarrier location: 16d (2k) -to- 16e/D9

[Mehul Mehta <MMEHTA@ALTERA.COM>]

Title: Downlink FUSC data subcarrier location: 16d (2k) -to- 16e/D9

Hello,

This query refers to section 8.4.6.1.2.2.2 (Partitioning of data subcarriers into subchannels in downlink FUSC).  Can anyone please help me clarify editorial changes in 16e drafts from 6 through to 9.

1)  The formula given in 802.16-2004 spec for 2k FFT is (on page 569):

subcarrier(k, s) = Nsubchannels ⋅ nk +{ps[nk mod Nsubchannels]+ IDcell} mod Nsubchannels

This is clarified in Cor1/D3a to be (on page 142 equation 111),

subcarrier (k, s) = Nsubchannels ⋅ nk +{ps[nk mod Nsubchannels]+ DL_PermBase} mod Nsubchannels

2) The referred section in 16e, draft 6 p.381 suggests the following:

8.4.6.1.2.2.2 Downlink subchannels subcarrier allocation
[Remove the two paragraphs in 8.4.6.1.2.2.1, and insert the following text:]
To allocate the subchannels, the whole data tones in a symbol are partitioned into groups of contiguous data
subcarriers. Each subchannel consists of one subcarrier from each of these groups. The number of groups is
therefore equal to number of data subcarriers per subchannel, and its value is 48. The number of the subcarriers
in a group is equal to the number of subchannels, say Ns. As shown in Table 310e, Ns is determined by
FFT size. The exact partitioning into subchannels is according to Equation Equation (110a), called DL permutation
formula.
(110a)
where
Carriers(s, m) = subcarrier index of m-th subcarrier in subchannel s
k=(m+s*23)mod 48, k’=k mod(Ns-1)
Carrier (s, m)
Ns k s P1 × +[+ , c1(k′)+P2, c2(k′)], 0 < c1, c2 < Ns
Ns k s P1 × +[+ , c1(k′)], c1 ≠ 0, c2 = 0
Ns k s P2 × +[+ , c2(k′)], c1 = 0, c2 ≠ 0
Ns k s + × c1 , 0 c2 , 0 =

3) In the latest 16e spec draft 9, this section (8.4.6.1.2.2.2) is not even defined.  And so it suggests that the appropriate section remains as in the base 16d spec (or more realistically, as in Cor1/D3a).

So taking into account points (1) (2) and (3) as above, can anyone shed some light on whether this section was mistakenly numbered in draft 6 of 16e as 8.4.6.1.2.2.2 instead of 8.4.6.1.2.3.1, as that would make sense.  The latter is an optional FUSC mode for downlink.

Thanks in advance

Micky