The cr,s,k values depend on the type of cell, as defined below.

For data/control cells (MSC, SDC, FAC), cr,s,k = z where z is the constellation point for each cell as given by the mappings defined in clause 7.

For each reference cell, a defined phase and amplitude is transmitted, cr,s,k =as,k Us,k , where:

as,k and ϑs,k are defined for each type of reference cell in clause 8.4.

8.2Propagation-related OFDM parameters

OFDM parameters shall be chosen to match propagation conditions and the coverage area that the operator wants to serve.

Various sets of OFDM parameters are therefore defined for different conditions of propagation and their parameter values are listed in table 47.

Table 47: Numerical values of the OFDM parameters

8.3Signal bandwidth related parameters

8.3.1Parameter definition

The OFDM parameters depend upon the available frequency bandwidth, the number of carriers K, and their location with respect to the reference frequency (named DC, in relation with the traditional carrier used in analogue transmissions).

The Spectrum occupancy defines the nominal channel bandwidth. For robustness modes A, B, C and D, the group of carriers carrying the FAC is always to the right (higher in frequency) with respect to the reference frequency, fR, which

is an integer multiple of 1 kHz. For robustness mode E, the group of carriers carrying the FAC is to the left and right (lower respectively higher in frequency) with respect to the reference frequency, fR, which is an integer multiple of

10 kHz. Table 48 relates the spectrum occupancy parameter, signalled in the FAC (see clause 6.3), to the nominal channel bandwidth, and figures 31 and 32 show the position of the carriers for fR < 30 MHz.

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119 ETSI ES 201 980 V4.1.2 (2017-04)

Table 48: Relationship between spectrum occupancy parameter and channel bandwidth

Spectrum occupancy 9 kHz

fR

Frequency

Figure 31: Spectrum occupancy for 9 kHz channels

Spectrum occupancy

10 kHz 1

5 kHz group containing FAC cells

3

5 kHz group of carriers

5

fR

Frequency

Figure 32: Spectrum occupancy for 10 kHz channels

The carriers are indexed by k [Kmin, Kmax], k = 0 being the DC carrier and determined by the following values depending on the choice made and related to the occupied bandwidth.

Carriers with k < 0 are said to be to the left of DC, and k > 0, to the right of DC.

Table 49 presents the lower and upper carrier numbers for each robustness mode and nominal bandwidth.

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