Method and transmitter for transmitting data in a multi-carrier system via a number of transmitting antennas
A method transmits data by radio during which a frequency band is split into a plurality of subcarriers, and a plurality of antennas are used for transmitting. The data are split into a number of elements, which are to be respectively transmitted by each antenna, said number of elements corresponding to the number of subcarriers, whereby for each antenna, each element is respectively assigned to a subcarrier for transmitting, and at least two antennas on at least one subcarrier transmit different elements. Before an OFDM modulation for each antenna, each element is multiplied by an antenna-specific and element-specific factor. Alternatively, after an OFDM modulation for at least one antenna, the time sequence of the time-dependent signal generated on the basis of the OFDM modulation is reordered. A transmitter carries out the method.
1. A method of transmitting data by radio, comprising:
using a plurality of subcarriers of a frequency band and a plurality of antennas for transmission such that each antenna transmits data using the plurality of the subcarriers;
dividing data for transmission into a plurality of elements such that the number of data elements corresponds to the number of subcarriers;
for each antenna, assigning each element to a subcarrier for transmission, such that for at least two antennas and at least one subcarrier, different elements are assigned to said one subcarrier; and
before performing an OFDM modulation for each antenna, multiplying each element by an antenna-specific and an element-specific factor.
2. The method in accordance with claim 1 , wherein the factor is a complex or real number, the absolute value of the factor being 1.
3. The method in accordance with claim 1 , wherein for at least two antennas a common pattern is used to assign each element to a corresponding subcarrier.
4. The method in accordance with claim 3 , wherein the common pattern is a cyclic permutation.
5. A method of transmitting data by radio, comprising:
using a plurality of subcarriers of a frequency band and a plurality of antennas for transmission such that each antenna transmits data using the plurality of the subcarriers;
dividing data for transmission into a plurality of data elements such that the number of data elements corresponds to the number of subcarriers;
for each antenna, assigning each element to a subcarrier for transmission, such that for at least two antennas and at least one subcarrier, different elements are assigned to said one subcarrier;
performing an OFDM modulation for each antenna to produce timing sequences of time-dependent signals; and
for at least one antenna, rearranging the order of the time-dependent signals after OFDM modulation.
6. The method in accordance with claim 5 , wherein for at least two antennas, the order is rearranged in accordance with a rearrangement common pattern.
7. The method in accordance with claim 6 , wherein the rearrangement common pattern is a cyclic permutation.
8. The method in accordance with claim 7 , wherein for at least two antennas an assignment common pattern is used to assign each element to a corresponding subcarrier.
9. The method in accordance with claim 8 , wherein the assignment common pattern is a cyclic permutation.
10. The method in accordance with claim 5 , wherein for at least two antennas a common pattern is used to assign each element to a corresponding subcarrier.
11. The method in accordance with claim 10 , wherein the common pattern is a cyclic permutation.
12. A transmitter to transmit data by radio using a plurality of subcarriers of a frequency band and a plurality of antennas for transmission such that each antenna transmits data using the plurality of subcarriers, comprising:
division means for dividing the data into a plurality of elements such that the number of elements corresponds with the number of subcarriers;
assignment means for assigning each element to a corresponding subcarrier, the elements being assigned individually for each antenna such that for at least two antennas and at least one subcarrier, different elements are assigned to said one subcarrier; and
an OFDM modulator to perform OFDM modulation for each antenna to produce time-dependent signals;
wherein the transmitter comprises either:
multiplication means for multiplying each element for each antenna by an antenna-specific and element-specific factor before OFDM modulation (OFDM), or
rearrangement means for rearranging the order of the time-dependent signals after OFDM modulation.