Enhanced OFDM by use of alternating polarization states
View Patent ↗An Orthogonal Frequency Division Multiplexer (OFDM) transmitter and receiver apparatus consistent with certain embodiments of the present invention receives data to be transmitted and maps ( 204 ) a first portion of the data to a first polarization state and a second portion of the data to a second polarization state. A first transmitter ( 216 ) transmits the first portion of the data as a set of first OFDM subcarriers using an antenna ( 230 ) exhibiting a first polarization. A second transmitter ( 234 ) transmits the second portion of the data as a set of second OFDM subcarriers using an antenna ( 240 ) exhibiting a second polarization, wherein the first polarization is orthogonal to the second polarization. A receiver apparatus uses a first antenna ( 302 ) exhibiting the first polarization and a second antenna ( 306 ) exhibiting the second polarization. A first OFDM receiver ( 310 ) receives a first set of polarized OFDM subcarriers from the first antenna ( 302 ) while a second OFDM receiver ( 324 ) receives a second set of polarized OFDM subcarriers from the second antenna ( 306 ). A decoder ( 330 ) decodes the first and second sets of OFDM subcarriers and combines them into a stream of data.
1. An Orthogonal Frequency Division Multiplexer (OFDM) transmitter apparatus, comprising:
N antennas having a corresponding set of N differing polarizations; and
a transmitter comprising a corresponding set of N transmitter branches coupled to drive the set of N antennas, wherein N is an integer, and wherein the corresponding set of N transmitter branches convert a sequence of data symbols to an ordered set of OFDM subchannels having a total bandwidth that is transmitted in a frequency band having the total bandwidth, wherein members of each pair of adjacent OFDM subchannels in the ordered set of OFDM subchannels are transmitted by different antennas of the set of N antennas.
2. The OFDM apparatus according to claim 1 , wherein N equals two and the set of polarizations consists of horizontal polarization and a vertical polarization.
3. The OFDM apparatus according to claim 1 , wherein members of the ordered set of OFDM sub-channels are transmitted simultaneously.
4. The OFDM apparatus according to claim 1 , wherein at least two members of the ordered set of OFDM sub-channels are transmitted at different times.
5. An Orthogonal Frequency Division Multiplexer (OFDM) transmitter apparatus, comprising:
a mapper that generates two data symbol sequences from a data symbol sequence source, wherein a first data symbol sequence comprises alternate data symbols selected from the data symbol source that are interleaved with null symbols that replace non-selected data symbols, and wherein a second data symbol sequence comprises the non-selected data symbols interleaved with null symbols that replace the selected data symbols;
a first transmitter branch that generates a first set of OFDM subcarriers from the first data symbol sequence;
a second transmitter branch that generates a second set of OFDM subcarriers from the second data symbol sequence;
a first RF transmitter that modulates the first set of OFDM subcarriers and transmits the modulated subcarriers as a first set of OFDM subchannels in a frequency band, using a first antenna exhibiting a first polarization; and
a second RF transmitter that modulates the second set of OFDM subcarriers and transmits the modulated subcarriers as a second set of OFDM subchannels in a frequency band, using a second antenna exhibiting a second polarization,
wherein the first polarization is different than the second polarization.
6. The OFDM apparatus according to claim 5 , wherein the set of polarizations consists of horizontal polarization and a vertical polarization.
7. The OFDM apparatus according to claim 5 , wherein members of the ordered set of OFDM sub-channels are transmitted simultaneously.
8. The OFDM apparatus according to claim 5 , wherein at least two members of the ordered set of OFDM sub-channels are transmitted at different times.
9. An Orthogonal Frequency Division Multiplexer (OFDM) transmitter apparatus, comprising:
a mapper that generates a set of N data symbol sequences from a data symbol sequence source, wherein each data symbol sequence comprises a unique subset of data symbols selected from the data symbol source that are interleaved with null symbols that replace non-selected data symbols;
a set of N corresponding transmitter branches, each corresponding transmitter branch generating a set of corresponding OFDM subcarriers from a corresponding one of the set of N data symbol sequences;
a set of N corresponding RF transmitters, each corresponding RF transmitter modulating one of the set of corresponding OFDM subcarriers and transmitting the modulated one of the set of corresponding OFDM subcarriers as one of a set of corresponding OFDM subchannels in a frequency band, using one of a set of corresponding antennas, wherein each antenna in the set of corresponding antennas exhibits a unique polarization, and wherein N is an integer.