Method for forming a DFT-spread OFDM symbol including data and pilots, comprising the Steps of:
- forming a pilot symbol in the time domain, the pilot symbol comprising at least two parts, a first part of the pilot symbol comprising samples of front pilots, a second part of the pilot symbol comprising null values and being consecutive to the first part of the pilot symbol,
- performing a DFT-spread OFDM modulation of the pilot symbol,
- precoding the data in order to compensate a modification of the data contribution onto a part of the DFT-spread OFDM modulated data symbol corresponding to the first part of the data symbol prior to the DFT-spread OFDM modulation,
- putting the precoded data under the form of a data symbol in the time domain, the data symbol comprising at least two parts, a first part of the data symbol comprising null values, a second part of the data symbol comprising the data, the second part of the data symbol being consecutive to the first part of the data symbol,
- performing a DFT-spread OFDM modulation of the data symbol,
- modifying the part of the DFT-spread OFDM modulated data symbol
corresponding to the first part of the data symbol prior to the DFT-spread OFDM
modulation in order to form a DFT-spread OFDM modulated data symbol to be
combined,
- combining the DFT-spread OFDM modulated data symbol to be combined to the
DFT-spread OFDM modulated pilot symbol in order to form a füll DFT-spread. OFDM
symbol. [Claim 2]
Method according to claim 1, wherein pilot samples at the end of the first part of
the pilot symbol are copied at the beginning of the first part of the pilot symbol. [Claim 3]
Method according to claim 1 or 2, wherein the modification of the data
contribution after a DFT-spread OFDM modulation of the data symbol consists in
zeroing the part of the DFT-spread OFDM modulated data symbol corresponding to the
first part of the data symbol prior to the DFT-spread modulation. [Claim 4]
Method according to any one of Claims 1 to 3, wherein the size of the first part of
the data symbol is identical to the size of the first part of the pilot symbol and the size of
the second part of the data symbol is identical to the size of the second part of the pilot
symbol.

[Claim 5]
Method according to any one of claims 1 to 4, wherein the pilot symbol comprises
a third part, the third part of the pilot symbol comprising end pilots and being
consecutive to the second part of the pilot symbol, the data symbol comprising a third
part, the third part of the data symbol comprising null values and being consecutive to
the second part of the data symbol. [Claim 6]
Method according to claim 5, wherein the modification of the data contribution
after a DFT-spread OFDM modulation of the data symbol is further performed onto the
end pilot. [Claim 7]
Method according to claim 6, wherein the samples of the end pilots are
determined so as to be as identical as possible to the samples copied at the beginning of
the first part of the pilot symbol. [Claim 8]
Method according to claim 7, wherein the samples of the end pilots determined so
as to be as identical as possible to the samples inserted at the beginning of the first part
of the pilot symbol are determinined according to a constrained quadratric distance. [Claim 9]
Method according to any one of claims 5 to 8, wherein the modification of the
data contribution after a DFT-spread OFDM modulation of the data symbol consists in
zeroing the part of the DFT-spread OFDM modulated data symbol corresponding to the
third part of the data symbol prior to the DFT-spread modulation. [Claim 10]
Method according to any one of claims 5 to 9, wherein the size of the third part of
the data symbol is identical to the size of the third part of the pilot symbol. [Claim 11]
Method according to any one of claims 1 to 10, wherein the part of the DFT-spread OFDM modulated pilot symbol corresponding to the second part of the pilot
symbol prior to the DFT-spread OFDM modulation is not modified. [Claim 12]
Device for forming a DFT-spread OFDM symbol including data and pilots,
comprising:
- means for forming a pilot symbol in the time domain, the pilot symbol
comprising at least two parts, a first part of the pilot symbol comprising front pilots, a
second part of the pilot symbol comprising null values and being consecutive to the first
part of the pilot symbol,
- means for performing a DFT-spread OFDM modulation of the pilot symbol,

- means for precoding the data in order to compensate a modification of the data contribution onto a part of the DFT-spread OFDM modulated data symbol corresponding to the first part of the data symbol prior to the DFT-spread OFDM modulation,
- means for putting the precoded data under the form of a data symbol in the time domain, the data symbol comprising at least two parts, a first part of the data symbol comprising null values, a second part of the data symbol comprising the data, the second part of the data symbol being consecutive to the first part of the data symbol,
- means for performing a DFT-spread OFDM modulation of the data symbol,
- means for modifying the part of the DFT-spread OFDM modulated data symbol corresponding to the first part of the data symbol prior to the DFT-spread OFDM modulation in order to form a DFT-spread OFDM modulated data symbol to be combined,
- means for combining the DFT-spread OFDM modulated data symbol to be combined to the DFT-spread OFDM modulated pilot symbol in order to form a füll DFT-spread OFDM symbol.