Estimating frequency-offsets and multi-antenna channels in mimo ofdm systems

A method comprising:

• receiving, by a wireless communication device, a wireless signal transmitted from a stream of two or more blocks of symbols, wherein each of the two or more blocks of symbols includes one or more information-bearing symbols, one or more training symbols, and at least one null subcarrier at a different position within each of the two or more blocks of symbols;
• estimating, by the wireless communication device, a carrier frequency offset of the received wireless signal based on the positions of the null subcarriers in the two or more blocks of symbols;
• and
• outputting, by the wireless communication device, estimated symbols based on the received wireless signal and the estimated carrier frequency offset.

A wireless communication device comprising:

• a training symbol insertion module to form two or more blocks of symbols by inserting training symbols within each of two or more blocks of information-bearing symbols, wherein the training symbol insertion module applies a hopping code to each of the two or more blocks of symbols to insert a null subcarrier at a different position within each of the two or more blocks of symbols;
• and
• a modulator to output a wireless transmission signal in accordance with the two or more blocks of symbols,
• wherein the wireless communication device applies the hopping code to insert the null subcarriers at different positions in the two or more blocks of symbols such that a second wireless communication device is operable to receive a wireless signal from the outputted wireless transmission signal and to estimate a carrier frequency offset of the received wireless signal based on the positions of the null subcarriers.

A wireless communication device comprising:

• one or more antennas that receive a wireless signal transmitted from a stream of two or more blocks of symbols, wherein each of the two or more blocks of symbols includes one or more information-bearing symbols, one or more training symbols, and at least one null subcarrier at a different position within each of the two or more blocks of symbols;
• a carrier frequency offset estimator to estimate a carrier frequency offset of the received wireless signal based on the positions of the null subcarriers in the two or more blocks of symbols;
• and
• a decoder to output a stream of estimated symbols based on the received wireless signal and the estimated carrier frequency offset.

A non-transitory computer-readable storage medium comprising instructions that cause a processor of a wireless communication device to:

• form two or more blocks of symbols by inserting training symbols within each of two or more blocks of information-bearing symbols;
• apply a hopping code to each of the two or more blocks of symbols to insert a null subcarrier at a different position within each of the two or more blocks of symbols;
• and
• output wireless transmission signal in accordance with the two or more blocks of symbols,
• wherein the hopping code is applied to insert the null subcarriers at different positions in the two or more blocks of symbols such that a second wireless communication device is operable to receive a wireless signal from the outputted wireless transmission signal and to estimate a carrier frequency offset of the received wireless signal based on the positions of the null subcarriers.

A non-transitory computer-readable storage medium comprising instructions that cause a processor of a wireless communication device to:

• receive a wireless signal transmitted from a stream of two or more blocks of symbols, wherein each of the two or more blocks of symbols includes one or more information-bearing symbols, one or more training symbols, and at least one null subcarrier at a different position within each of the two or more blocks of symbols;
• estimate a carrier frequency offset of the received wireless signal based on the null subcarriers included in the two or more blocks of symbols;
• and
• output estimated symbols based on the received wireless signal and the estimated carrier frequency offset.