Pilot transmission and channel estimation for an ofdm system with excess delay spread

In an apparatus for transmitting pilots in an OFDM wireless data communication system, in which a given receiver observes excess delay spread greater than the cyclic prefix length, the improvement of mitigating deleterious effects of intersymbol interference (ISI) and channel estimation errors comprising:

• at least one processor configured to transmit a first set of pilot subbands in a first symbol period, and
• transmit a second set of pilot subbands in a second symbol period, wherein the first set of pilot subbands and the second set of pilot subbands are staggered in frequency, and the number of pilot subbands selected are greater than the cyclic prefix length (NPeff>Ncp) to achieve oversampling in the frequency domain;
• and
• a memory coupled to the at least one processor.

In an apparatus for transmitting pilots in an OFDM wireless data communication system, in which a given receiver observes excess delay spread greater than the cyclic prefix length, the improvement of mitigating deleterious effects of intersymbol interference (ISI) and channel estimation errors comprising:

• means for transmitting a first set of pilot subbands in a first symbol period;
• and
• means for transmitting a second set of pilot subbands in a second symbol period,
• wherein the first set of pilot subbands and the second set of pilot subbands are staggered in frequency, and the number of pilot subbands selected are greater than the cyclic prefix length (NPeff>Ncp) to achieve oversampling in the frequency domain.

A computer program product, comprising:

• a computer-readable medium for transmitting pilots in an OFDM wireless data communication system in which a given receiver observes excess delay spread greater than the cyclic prefix length, by the improvement of mitigating deleterious effects of intersymbol interference (ISI) and channel estimation errors, comprising:
• code for causing at least one computer to transmit a first set of pilot subbands in a first symbol period, and
• code for causing the at least one computer to transmit a second set of pilot subbands in a second symbol period,
• wherein the first set of pilot subbands and the second set of pilots subbands are staggered in frequency, and the number of pilot subbands selected are greater than the cyclic prefix length (NPeff>Ncp) to achieve oversampling in the frequency domain.

In a method for receiving pilots in an OFDM wireless data communication system in which a given receiver observes excess delay spread greater than the cyclic prefix length, the improvement of mitigating deleterious effects of intersymbol interference (ISI) and channel estimation errors, comprising:

• receiving a first set of pilot subbands in a first symbol period;
• and
• receiving a second set of pilot subbands in a second symbol period,
• wherein the first set of pilot subbands and the second set of pilot subbands are staggered in frequency, and the number of pilot subbands selected are greater than the cyclic prefix length (NPeff>Ncp) to achieve oversampling in the frequency domain.

In an apparatus for receiving pilots in an OFDM wireless data communication system in which a given receiver observes excess delay spread greater than the cyclic prefix length, the improvement of mitigating deleterious effects of intersymbol interference (ISI) and channel estimation errors, comprising:

• at least one processor configured to
• receive a first set of pilot subbands in a first symbol period, and
• receive a second set of pilot subbands in a second symbol period, wherein the first set of pilot subbands and the second set of pilot subbands are staggered in frequency, and wherein the number of pilot subbands selected are greater than the cyclic prefix length (NPeff>Ncp) to achieve oversampling in the frequency domain;
• and
• a memory coupled to the at least one processor.

In an apparatus for receiving pilots in an OFDM wireless data communication system in which a given receiver observes excess delay spread greater than the cyclic prefix length, the improvement of mitigating deleterious effects of intersymbol interference (ISI) and channel estimation errors, comprising:

• means for receiving a first set of pilot subbands in a first symbol period;
• and
• means for receiving a second set of pilot subbands in a second symbol period,
• wherein the first set of pilot subbands and the second set of pilot subbands are staggered in frequency, and the number of pilot subbands selected are greater than cyclic prefix length (NPeff>Ncp) to achieve oversampling in the frequency domain.