116 ETSI ES 201 980 V4.1.2 (2017-04)
Table 44: Number of QAM cells for MSC for robustness mode D
Parameters |
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|
Spectrum occupancy |
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|
0 |
1 |
2 |
3 |
4 |
5 |
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Number of available MSC |
- |
- |
- |
3 679 |
- |
7 819 |
|
cells per super frame NSFA |
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Number of useful MSC cells |
- |
- |
- |
3 678 |
- |
7 818 |
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per super frame NSFU |
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Number of MSC cells per |
- |
- |
- |
1 226 |
- |
2 606 |
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multiplex frame NMUX |
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Cell loss per super frame NL |
- |
- |
- |
1 |
- |
1 |
|
Table 45: Number of QAM cells for MSC for robustness mode E
Parameters |
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Spectrum occupancy |
|
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||
|
0 |
1 |
2 |
3 |
4 |
5 |
|
Number of available MSC |
29 842 |
- |
- |
- |
- |
- |
|
cells per super frame NSFA |
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Number of useful MSC cells |
29 840 |
- |
- |
- |
- |
- |
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per super frame NSFU |
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Number of MSC cells per |
7 460 |
- |
- |
- |
- |
- |
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multiplex frame NMUX |
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Cell loss per super frame NL |
2 |
- |
- |
- |
- |
- |
|
So the overall data vector for the useful MSC cells in transmission super frame m can be described by:
Sm =(sm,0,sm,1,sm,2,...,sm,N |
) |
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SFU−1 |
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ˆ |
ˆ |
ˆ |
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=(ZMTF *m,ZMTF*m+1,...,ZMTF *m+MTF −1) |
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=(zˆMTF*m,0,zˆMTF*m,1,...,zˆMTF *m,NMUX−1,zˆMTF*m+1,0,zˆMTF*m+1,1,...,zˆMTF*m+1,NMUX−1,...,zˆMTF *m+MTF −1,0,zˆMTF*m+MTF −1,1,...,zˆMTF*m+MTF −1,NMUX−1) |
||||
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~ |
~ |
~ |
In the case that NL is unequal to 0 one or two dummy cells, i.e. (zm,0 ) or |
(zm,0 |
, zm,1), are attached at the end of Sm . |
||
Their complex values (i.e. the corresponding QAM symbols) are as defined in table 46.
Table 46: QAM symbols for MSC dummy cells
Number of dummy cells NL per |
Complex values of the dummy cells (QAM symbols) |
|
transmission super frame |
~ |
~ |
zm,0 |
zm,1 |
|
1 |
a × (1 + j 1) |
|
2 |
a × (1 + j 1) |
a × (1 - j 1) |
The value of a in table 46 is dependent on the signal constellation chosen for the MSC (see clause 7.4).
8 Transmission structure
8.1Transmission frame structure and robustness modes
The transmitted signal is organized in transmission super frames.
For robustness modes A, B, C and D, each transmission super frame consists of three transmission frames. For robustness mode E, each transmission super frame consists of four transmission frames.
Each transmission frame has duration Tf, and consists of Ns OFDM symbols.
ETSI
117 |
ETSI ES 201 980 V4.1.2 (2017-04) |
Each OFDM symbol is constituted by a set of K carriers and transmitted with a duration Ts. The spacing between adjacent carriers is 1/Tu.
The symbol duration is the sum of two parts:
•a useful part with duration Tu;
•a guard interval with duration Tg.
The guard interval consists in a cyclic continuation of the useful part, Tu, and is inserted before it.
The OFDM symbols in a transmission frame are numbered from 0 to Ns - 1.
All symbols contain data and reference information.
Since the OFDM signal comprises many separately modulated carriers, each symbol can in turn be considered to be divided into cells, each cell corresponding to the modulation carried on one carrier during one symbol.
An OFDM frame contains:
•pilot cells;
•control cells;
•data cells.
The pilot cells can be used for frame, frequency and time synchronization, channel estimation, and robustness mode identification.
The transmitted signal is described by the following expression:
|
∞ |
Ns −1 Kmax |
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x(t) = Re e j2π fR t ∑ ∑ ∑cr,s,k |
ψ r,s,k |
(t) k |
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r=0 |
s=0 k=Kmin |
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where:
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j2π |
k |
(t−Tg−sTs−Ns rTs ) |
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T |
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u |
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(s+Ns r)Ts ≤ t ≤(s+Ns r+1)Ts |
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e |
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ψr,s,k (t) = |
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otherwise |
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0 |
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and: |
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Ns |
number of OFDM symbols per transmission frame; |
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k |
denotes the carrier number (= Kmin, … , Kmax); |
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s |
denotes the OFDM symbol number (= 0 to Ns - 1); |
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r |
denotes the transmission frame number (= 0 to infinity); |
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K |
is the number of transmitted carriers (≤ Kmax - Kmin); |
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Ts |
is the symbol duration; |
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Tu |
is the duration of the useful part of a symbol; |
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Tg |
is the duration of the guard interval; |
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fR |
is the reference frequency of the RF signal; |
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cr,s,k |
complex cell value for carrier k in symbol s of frame number r. |
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ETSI