Abstract: Systems and methods for temperature-calibration of an uncompensated XO in a mobile device during mobile device operation. The XO is temperature-calibrated based on assistance from wireless signals, such as from satellite source, and optionally from terrestrial sources such as WWAN, CDMA, etc. Based on one or more received wireless signals received at a receiver, corresponding frequency estimates of the XO are obtained and correlated with corresponding operating temperatures in a processor. Based on one or more samples of frequency estimates and associated temperatures, the XO is temperature-calibrated in the processor wherein a frequency-temperature (FT) model is formulated for the XO. The frequency of the temperature-calibrated XO can be determined from the FT model at any given temperature.

Abstract: System and method for temperature-calibration of a crystal oscillator (XO) in a mobile device. A temperature-calibration status of the XO is determined and a trigger condition related to temperature-calibration of the XO is detected. If the temperature-calibration status of the XO is not fully temperature-calibrated or if the XO has not been previously temperature-calibrated, a temperature-calibration session is initiated by an XO manager based on the condition, wherein a receiver is configured to receive signals and temperature-calibration of the XO is performed in a background mode based on the received signals. The condition based triggering ensures that the XO is temperature-calibrated prior to launch of any position based or global navigation satellite systems (GNSS) based applications on the mobile device.

Abstract: A method in a mobile communication device includes: measuring a first temperature associated with a crystal configured to provide a reference signal having a frequency; measuring a second temperature associated with a component that is coupled to the crystal by an electrically and thermally conductive line; and compensating, based upon the measuring of the first and second temperatures, for a change in the frequency of the reference signal of the crystal.

Abstract: This disclosure provides systems, methods, and apparatus for antenna switching for simultaneous communication. An can include a plurality of antennas including a first antenna and a second antenna. The apparatus can further includes a plurality of receive circuits including a first receive circuit. The apparatus can further include a controller configured to determine one or more performance characteristics of the first antenna at a first time. The controller is further configured to determine a difference between the one or more performance characteristics of the first antenna at the first time and one or more performance characteristics of the first antenna at an earlier time. The controller is further configured to selectively switch the first receive circuit from receiving wireless communications via the first antenna to receive wireless communications via the second antenna if the difference is larger than a threshold. Other aspects, embodiments, and features are also claimed and described.

Abstract: This disclosure provides systems, methods, and apparatus for antenna switching for simultaneous communication. In one embodiment, a wireless communication apparatus is provided. The wireless communication apparatus includes a plurality of antennas including a first antenna and a second antenna. The wireless communication apparatus further includes a plurality of transmit circuits including a first transmit circuit. The wireless communication apparatus further includes a controller configured to selectively switch the first transmit circuit from transmitting wireless communications via the first antenna to transmit wireless communications via the second antenna based on one or more uplink performance characteristics of at least one of the first antenna and the second antenna. Other aspects, embodiments, and features are also claimed and described.

Abstract: This disclosure provides systems, methods, and apparatus for antenna switching. In one embodiment, a wireless communication apparatus is provided. The wireless communication apparatus includes a plurality of antennas including a first antenna and a second antenna. The wireless communication apparatus further includes at least one receive circuit including a first receive circuit. The wireless communication apparatus further includes a controller configured to selectively switch the first receive circuit from receiving wireless communications via the first antenna to receive wireless communications via the second antenna if one or more performance characteristics of the first antenna are below a threshold in one or more measurement cycles, the one or more measurement cycles including a wake-up cycle outside of a predetermined wake-up cycle. Other aspects, embodiments, and features are also claimed and described.

Abstract: This disclosure provides systems, methods, and apparatus for antenna switching for simultaneous communication. One apparatus embodiment includes a plurality of antennas including a first antenna, a second antenna, and a third antenna. The wireless communication apparatus further includes a plurality of receive circuits including a first receive circuit, at least two of the plurality of receive circuits each configured to simultaneously receive, with respect to the other, wireless communications from a different one of at least two networks relating to different radio access technologies. The wireless communication apparatus further includes a controller configured to selectively switch the first receive circuit from receiving wireless communications via the first antenna to receive wireless communications via the second antenna based on one or more performance characteristics of at least one of the first antenna and the second antenna. Other aspects, embodiments, and features are also claimed and described.

Abstract: This disclosure provides systems, methods, and apparatus for antenna switching for simultaneous communication. In one embodiment, a wireless communication apparatus is provided. The wireless communication apparatus includes a plurality of antennas including a first antenna and a second antenna. The wireless communication apparatus further includes a plurality of receive circuits including a first receive circuit. The wireless communication apparatus further includes a controller configured to determine one or more performance characteristics of the first antenna over a plurality of sources. The controller is further configured to selectively switch the first receive circuit from receiving wireless communications via the first antenna to receive wireless communications via the second antenna if the one or more performance characteristics of the first antenna over the plurality of sources fall simultaneously. Other aspects, embodiments, and features are also claimed and described.

Abstract: This disclosure provides systems, methods, and apparatus for adjusting probing distances. In one embodiment, a wireless communication apparatus is provided. The wireless communication apparatus includes a plurality of antennas including a first antenna and a second antenna. The wireless communication apparatus further includes a plurality of receive circuits including a first receive circuit coupled to the first antenna and a second receive circuit coupled to the second antenna. The first receive circuit is configured to measure one or more downlink performance characteristics of the first antenna and the second receive circuit is configured to measure one or more downlink performance characteristics of the second antenna during at least part of a same time period.

Abstract: This disclosure provides systems, methods, and apparatus for an initial network acquisition process via multiple antennas. In one aspect a method of establishing communications via a wireless network at a wireless communications apparatus is provided. The method includes attempting an initial acquisition process, over one or more frequencies, for establishing communications over the wireless network via a transmit circuit and a receive circuit transmitting and receiving via a first antenna. The method further includes switching the transmit circuit and the receive circuit from transmitting and receiving via the first antenna to a second antenna in response to detecting failure of the initial acquisition process. The switching is independent of a performance metric of the first or the second antenna. The method further includes re-attempting the initial acquisition process based on the switching to the second antenna over the one or more frequencies.

Abstract: A method, an apparatus, and a computer program product for wireless communication are provided in connection with improving antenna selection for a UE as part of an access procedure. In an example, a UE with two or more antennas is equipped to obtain receive chain measurements for the two or more antennas associated with the UE when an access procedure is initiated, select an antenna, of the two or more antennas, for transmission based on receive chain measurements for use during at least a portion of the access procedure, and perform the access procedure using the selected antenna. In another example, the UE is equipped to determine that an Access procedure is to be initiated, select an antenna from the two or more antennas based on a selection algorithm, and perform the Access procedure based using the selected antenna. Other aspects, embodiments, and features are also claimed and described.

Abstract: A wireless communication apparatus is provided that includes a plurality of antennas and at least one receive or transmit circuit. The apparatus further includes a controller configured to: determine one or more performance characteristics associated with a first antenna while the circuit is connected to the first antenna; switch the circuit from the first antenna to a second antenna; determine one or more performance characteristics associated with the second antenna after the switch; compare the performance characteristics associated with the antennas; determine whether to maintain the switch to the second antenna or to switch the circuit back to the first antenna; and determine a duration of time to maintain a connection between the selected antenna and the circuit based, at least, on one or more performance characteristics. Other aspects, embodiments, and features are also claimed and described.

Abstract: This disclosure provides systems, methods, and apparatus for mobile transmit diversity. In one aspect, a wireless communication apparatus is provided. The wireless communication apparatus includes a transmit circuit configured to transmit wireless communications via either a first antenna or a second antenna. The wireless communication apparatus further includes a receive circuit configured to receive wireless communications using either the first antenna or the second antenna.

Abstract: This disclosure provides systems, methods, and apparatus for antenna selection for different radio access technologies. An apparatus can include a plurality of antennas and a plurality of radio access technology modules each configured to communicate according to a different radio access technology. The apparatus further includes a controller configured to switch communication circuits of each of the radio access technology modules to communicate via a corresponding one or more of the plurality of antennas. The apparatus further includes a switching manager configured to manage a plurality of switch configurations each defining a mapping between each of the radio access technology modules and the antennas. The switching manager is further configured to store a switch configuration used for a first radio access technology module and cause the controller to maintain the switch configuration in place in response to a network handover. Other aspects, embodiments, and features are also claimed and described.

Abstract: A method and apparatus for eliminating receive band noise in a communication system is provided. The method comprises sensing a transmit signal at a receive frequency, wherein the signal sensed is a bleed over signal from a transmit signal. The sensed bleed over signal is then digitized using a secondary receiver. This secondary receiver utilizes a separate path from the primary receive path. The next step in the method is to estimate the linear distortion, delay, attenuation in the sensed bleed over signal. Next, compensation for the linear distortion, delay, and attenuation are performed on the sensed bleed over signal. The sensed, digitized, and compensated bleed over signal is then cancelled from the primary receive path.

Abstract: Techniques for identifying and suppressing frequency spurs in a signal are disclosed. In an embodiment, an incoming signal is rotated by a frequency related to a spur frequency, and an estimate of the content of the rotated signal is derived. The estimate may be subtracted from the rotated incoming signal, and the result de-rotated by the spur frequency. In an embodiment, the incoming signal may be rotated such that the spur is centered at DC. In an alternative embodiment, the estimate may be de-rotated before being subtracted from the original incoming signal. Techniques for addressing multiple spurs using serial and parallel architectures are disclosed. Further disclosed are techniques for searching for the presence of spurs in an incoming signal, and tracking spur frequencies over time.

Abstract: Techniques for identifying and suppressing frequency spurs in a signal are disclosed. In an embodiment, an incoming signal is rotated by a frequency related to a spur frequency, and an estimate of the content of the rotated signal is derived. The estimate may be subtracted from the rotated incoming signal, and the result de-rotated by the spur frequency. In an embodiment, the incoming signal may be rotated such that the spur is centered at DC. In an alternative embodiment, the estimate may be de-rotated before being subtracted from the original incoming signal. Techniques for addressing multiple spurs using serial and parallel architectures are disclosed. Further disclosed are techniques for searching for the presence of spurs in an incoming signal, and tracking spur frequencies over time.

Abstract: Techniques are disclosed for estimating a frequency of a crystal oscillator based on temperature. In an embodiment, the oscillator frequency is computed using a polynomial approximation. Techniques are disclosed for deriving and periodically updating the coefficients used in the polynomial approximation.

Abstract: Methods and apparatus for generating a temperature compensated frequency estimate for a crystal oscillator, wherein the temperatures of the crystal and oscillator are both accounted for. A crystal temperature measurement is used to generate a first frequency component. The difference between the oscillator temperature measurement and a second temperature is scaled, and used to generate a second frequency component. The first and second frequency components may be summed to produce a frequency estimate for the crystal oscillator. In an embodiment, the computations may be performed in the slope domain.