Back to results
US 8,711,983 B2Granted
Phase locking loop
AssigneeTexas Instruments Incorporated
InventorsTaejoon Kim, Timothy M. Schmidl, Srinath Hosur
Life of this patent
Estimating the term…
Abstract
A phase-locking loop (PLL) for use with orthogonal frequency division multiplexed signals. In one embodiment, a wireless receiver includes a PLL is configured to reduce phase and frequency divergence between the wireless receiver and a transmitter of a packet received by the wireless receiver. The PLL includes a loop bandwidth controller. The loop bandwidth controller is configured to set a bandwidth of the PLL to a first value for reception of an initial symbol of the packet. The loop bandwidth controller is configured to reduce the bandwidth of the PLL over a number of symbols preceding an initial header of the packet.
Claims19
A wireless receiver, comprising:
- a phase-locking loop configured to reduce phase and frequency divergence between the wireless receiver and a transmitter of a packet received by the wireless receiver, the phase-locking loop comprising:
- a loop bandwidth controller configured to:
- set a bandwidth of the phase-locking loop to a first value for reception of an initial symbol of the packet;
- and
- reduce the bandwidth of the phase-locking loop over a number of symbols following the initial symbol and preceding an initial header of the packet;
- wherein the phase-locking loop comprises a phase estimator, the phase estimator comprising:
- a mean computation block configured to compute a mean of pilot symbols extracted from the packet;
- and
- a phase detector configured to estimate phase error between an oscillator of the receiver and an oscillator of the transmitter based on the mean of the pilot symbols.
6 more elements
A wireless receiver, comprising:
- a phase-locking loop configured to reduce phase and frequency divergence between the wireless receiver and a transmitter of a packet received by the wireless receiver, the phase-locking loop comprising:
- a loop bandwidth controller configured to:
- set a bandwidth of the phase-locking loop to a first value for reception of an initial symbol of the packet;
- and
- reduce the bandwidth of the phase-locking loop over a number of symbols following the initial symbol and preceding an initial header of the packet;
- wherein the phase-locking loop comprises a phase estimator, the phase estimator comprising a despreader configured to despread, prior to phase estimation, header and data symbols of the packet in accordance with a frequency domain spreading factor applied at the transmitter.
3 more elements
A wireless receiver, comprising:
- a phase-locking loop configured to reduce phase and frequency divergence between the wireless receiver and a transmitter of a packet received by the wireless receiver, the phase-locking loop comprising:
- a loop bandwidth controller configured to:
- set a bandwidth of the phase-locking loop to a first value for reception of an initial symbol of the packet;
- and
- reduce the bandwidth of the phase-locking loop over a number of symbols following the initial symbol and preceding an initial header of the packet;
- wherein the phase-locking loop comprises a power loop configured to extract phase offset from a received data symbol of the packet by computing a fraction of the data symbol raised to a power;
- wherein the fraction and the power are determined based on a type of modulation applied to the data symbol at the transmitter.
4 more elements
A wireless receiver, comprising:
- a phase-locking loop configured to reduce phase and frequency divergence between the wireless receiver and a transmitter of a packet received by the wireless receiver, the phase-locking loop comprising:
- a loop bandwidth controller configured to:
- set a bandwidth of the phase-locking loop to a first value for reception of an initial symbol of the packet;
- and
- reduce the bandwidth of the phase-locking loop over a number of symbols following the initial symbol and preceding an initial header of the packet;
- wherein the phase-locking loop comprises:
- a mean calculator configured to compute a mean of phase offsets extracted from data symbols of the packet;
- and
- a phase detector configured to estimate phase error between an oscillator of the receiver and an oscillator of the transmitter based on the mean of the phase offsets.
6 more elements
A method, comprising:
- initializing a phase locking loop of a wireless receiver to operate with a first bandwidth for reception of a wirelessly transmitted orthogonal frequency multiplexed packet;
- reducing bandwidth of the phase-locking loop from the first bandwidth to a second bandwidth as symbols preceding an initial header of the packet are received;
- wherein the first bandwidth provides fast carrier acquisition, and the second bandwidth provides lower phase noise than the first bandwidth;
- computing a mean of pilot symbols extracted from the packet;
- and
- estimating a phase error between an oscillator of the wireless receiver and an oscillator of a transmitter based on the mean of the pilot symbols.
3 more elements
A method, comprising:
- initializing a phase locking loop of a wireless receiver to operate with a first bandwidth for reception of a wirelessly transmitted orthogonal frequency multiplexed packet;
- reducing bandwidth of the phase-locking loop from the first bandwidth to a second bandwidth as symbols preceding an initial header of the packet are received;
- wherein the first bandwidth provides fast carrier acquisition, and the second bandwidth provides lower phase noise than the first bandwidth;
- determining a type of modulation applied at transmission of the packet;
- raising, to a power, a data symbol extracted from the packet;
- extracting a phase offset from the data symbol by computing a fraction of the data symbol raised to the power;
- wherein the power and the fraction are based on the type of modulation.
4 more elements
A method, comprising:
- initializing a phase locking loop of a wireless receiver to operate with a first bandwidth for reception of a wirelessly transmitted orthogonal frequency multiplexed packet;
- reducing bandwidth of the phase-locking loop from the first bandwidth to a second bandwidth as symbols preceding an initial header of the packet are received;
- wherein the first bandwidth provides fast carrier acquisition, and the second bandwidth provides lower phase noise than the first bandwidth;
- computing a mean of phase offsets extracted from data symbols of the packet;
- and
- estimating phase error between an oscillator of the receiver and an oscillator of a transmitter based on the mean of the phase offsets.
3 more elements
A system, comprising:
- a first wireless device configured to receive a wirelessly transmitted orthogonal frequency division multiplexed packet with frequency domain spreading, the first wireless device comprising:
- a phase-locking loop configured to lock the first wireless device to a carrier frequency of the packet, the phase-locking loop comprising:
- a despreader configured to despread, prior to phase estimation, header and data symbols of the packet in accordance with a frequency domain spreading factor applied to the packet at transmission;
- and
- a power loop coupled to an output of the despreader, the power loop configured to extract phase offset from a despread data symbol by computing a fraction of the data symbol raised to a power;
- wherein the fraction and the power are determined based on a type of modulation applied to the packet at transmission.
3 more elements
Dependencies are inferred from the claim text.