Adaptive channel prediction and mitigating interference in OFDM systems
View Patent ↗One embodiment provides an apparatus. The apparatus includes an optimization module configured to determine a guard interval remainder based, at least in part on a comparison of an allowable microreflection interference level and an actual microreflection interference level; and a windowing module configured to window an OFDM (orthogonal frequency division multiplexed) symbol utilizing the guard interval remainder. The apparatus may further include a channel estimator module configured to determine a predicted channel frequency response based, at least in part, on a probing symbol; and a pre-equalizer module configured to pre-equalize the OFDM symbol based, at least in part, on the predicted channel frequency response.
1. An apparatus, comprising:
pre-equalizer circuitry configured to pre-equalize an orthogonal frequency division multiplexed (OFDM) symbol based, at least in part, on a predicted channel frequency response, wherein the predicted channel frequency response is determined based, at least in part, on a probing symbol;
optimization circuitry configured to determine a guard interval remainder based, at least in part, on a comparison of an allowable microreflection interference level and an actual microreflection interference level; and
windowing circuitry configured to window the OFDM symbol utilizing the guard interval remainder.
2. The apparatus of claim 1 , wherein the optimization circuitry is further configured to determine the allowable microreflection interference level based on a quadrature amplitude modulation (QAM) constellation.
3. The apparatus of claim 1 , wherein the optimization circuitry is further configured to determine the actual microreflection interference level based, at least in part, on a channel impulse response.
4. The apparatus of claim 1 , wherein the pre-equalizer circuitry is further configured to pre-equalize the probing symbol.
5. The apparatus of claim 1 , wherein the predicted channel frequency response is time varying with non-time varying components removed.
6. A method, comprising:
pre-equalizing, by pre-equalizer circuitry, or equalizing, by equalizer circuitry, or both pre-equalizing and equalizing, an orthogonal frequency division multiplexed (OFDM) symbol based, at least in part, on a predicted channel frequency response, wherein the predicted channel frequency response is determined, at least in part, on a probing symbol;
determining, by optimization circuitry, a guard interval remainder based, at least in part on a comparison of an allowable microreflection interference level and an actual microreflection interference level; and
windowing, by windowing circuitry, the OFDM symbol utilizing the guard interval remainder.
7. The method of claim 6 , further comprising: determining, by the optimization circuitry, the allowable microreflection interference level based on a quadrature amplitude modulation (QAM) constellation.
8. The method of claim 6 , further comprising: determining, by the optimization circuitry, the actual microreflection interference level based, at least in part, on a channel impulse response.
9. The method of claim 6 , further comprising: pre-equalizing, by the pre-equalizer circuitry, the probing symbol.
10. The method of claim 6 , wherein the predicted channel frequency response is time varying with non-time varying components removed.
11. A system comprising, one or more non-transitory computer memories having stored thereon, individually or in combination, instructions that when executed by one or more processors result in the following operations comprising:
pre-equalizing or equalizing or both pre-equalizing and equalizing, an orthogonal frequency division multiplexed (OFDM) symbol based, at least in part, on a predicted channel frequency response, wherein the predicted channel frequency response is determined based, at least in part, on a probing symbol;
determining a guard interval remainder based, at least in part on a comparison of an allowable microreflection interference level and an actual microreflection interference level; and
windowing the OFDM symbol utilizing the guard interval remainder.
12. The system of claim 11 , wherein the instructions that when executed by the one or more processors results in the following additional operations comprising: determining the allowable microreflection interference level based on a quadrature amplitude modulation (QAM) constellation.
13. The system of claim 11 , wherein the instructions that when executed by the one or more processors results in the following additional operations comprising: determining the actual microreflection interference level based, at least in part, on a channel impulse response.
14. The system of claim 11 , wherein the instructions that when executed by the one or more processors results in the following additional operations comprising: pre-equalizing the probing symbol.
15. The system of claim 11 , wherein the predicted channel frequency response is time varying with non-time varying components removed.