摘要:
Techniques for performing time tracking in a communication system utilizing a cyclic prefix are described. In an aspect, a receiver may detect for large timing errors based on early and late received samples obtained with early and late FFT windows, respectively. The receiver may derive first and second channel impulse response (CIR) estimates based on the early and late received samples, respectively, determine an early channel energy based on the first CIR estimate, determine a late channel energy based on the second CIR estimate, compute an update amount based on the early and late channel energies, and update the FFT window position based on the update amount. In another aspect, the receiver may perform time tracking with an inner time tracking loop (TTL) and an outer TTL. The receiver may update the FFT window position in coarse steps with the outer TTL and in fine steps with the inner TTL.
摘要:
Techniques for performing time tracking in a communication system utilizing a cyclic prefix are described. In an aspect, a receiver may detect for large timing errors based on early and late received samples obtained with early and late FFT windows, respectively. The receiver may derive first and second channel impulse response (CIR) estimates based on the early and late received samples, respectively, determine an early channel energy based on the first CIR estimate, determine a late channel energy based on the second CIR estimate, compute an update amount based on the early and late channel energies, and update the FFT window position based on the update amount. In another aspect, the receiver may perform time tracking with an inner time tracking loop (TTL) and an outer TTL. The receiver may update the FFT window position in coarse steps with the outer TTL and in fine steps with the inner TTL.
摘要:
Methods and apparatus for correcting frequency errors between a carrier frequency of a signal received by a wireless device and a reference frequency local to the device. For certain aspects, such a method generally includes receiving a signal in a receiver having an LO producing a reference frequency, a radio frequency (RF) phase-locked loop (PLL), and a digital rotator, estimating a frequency difference between a carrier frequency of the received signal and the LO reference frequency, and applying the estimated frequency difference to the RF PLL and the digital rotator.
摘要:
Methods and apparatus for correcting frequency errors between a carrier frequency of a signal received by a wireless device and a reference frequency local to the device. For certain aspects, such a method generally includes receiving a signal in a receiver having an LO producing a reference frequency, a radio frequency (RF) phase-locked loop (PLL), and a digital rotator, estimating a frequency difference between a carrier frequency of the received signal and the LO reference frequency, and applying the estimated frequency difference to the RF PLL and the digital rotator.