1. A method implemented by computer means of a communicating entity, for
inserting a reference signal for phase tracking, said communicating entity using a
5 discrete Fourier transformation spread orthogonal frequency division multiplexing
modulator,
characterized in that the method comprises:
- obtaining a succession of signal samples by inserting said reference signal for
phase tracking within a succession of data samples, according to at least one insertion
10 pattern chosen among pre-defined patterns with respect to predetermined criteria of
communication conditions, and
- feeding said modulator with a succession of signal blocks obtained from said
succession of signal samples, so as to apply the discrete Fourier transformation after the
insertion of the reference signal for phase tracking;
15 wherein a transformed succession of signal blocks resulting at least from the
application of the discrete Fourier transformation to said succession of signal blocks
includes transformed signal blocks, each transformed signal block being mapped to
active carriers, and wherein said chosen pattern is composed of groups of at least two
reference signal for phase tracking, two groups being separated by data samples.
20
2. The method according to claim 1, wherein one of the predetermined criteria of
communication conditions is at least one of the following:
- scheduled bandwidth;
- modulation;
25 - coding rate;
- carrier frequency;
- physical resource block bundling; or
- other reference signal densities.
30 3. The method according to anyone of claims 1 and 2, wherein a reference signal for
demodulation is further inserted within said transformed succession of signal blocks
resulting at least from the application of the discrete Fourier transformation to said
succession of signal blocks, said reference signal for demodulation being inserted in
26
scheduled positions of the transformed succession of signal blocks, and wherein said
chosen pattern is based on said scheduled positions.
4. The method according to anyone of the precedent claims, wherein said
5 transformed succession of signal blocks includes Ndata transformed signal blocks, each
transformed signal block being mapped to M active carriers, and wherein said chosen
pattern is composed of Nk groups of Ki reference signal for phase tracking separated by
Di data samples, such as:
1
0 0
N N k k
i i data
i i
K D MN
−
= =
 + =
10 Where Di are non-null positive integers when i is different from 0 and Nk
and wherein = = ⋯ = ≥ 2
5. The method according to claim 4, wherein: 0
0 NK
D D= = .
6. The method according to anyone of claims 4 and 5, wherein: 1 2 1 .... NK
15 D D D = = = − .
7. The method according to anyone of claims 4 to 6, wherein: 0 1 1 .... NK
K K K = = = − .
8. The method according to anyone of claims 4 to 6, wherein:
1 2 0 1 .... N N K K
K K K K = = = + − − 20 .
9. The method according to anyone of claims 4 to 8, wherein:
(
+ ∑

( +
)) =
for each k from 0 to − 2.
25 10. The method according to anyone of claims 4 to 8, wherein:
∑ (
+ )) = (
+

for each k from 0 to − 1.