Abstract: A method and apparatus for estimating the presence of RF interference in a wireless data channel is described. The method and apparatus comprises a set of identical tracking/register (T/R) filter blocks, each T/R filter block associated and corresponding to an RF channel of interest. Each T/R filter block includes a pair of tracking/register (T/R) filters. Power/magnitude estimates from an RSSI calculation are input to the T/R filter blocks. One T/R filter is used to estimate the noise floor (in the absence of interference). The T/R filter latches and filters the lowest input values received from a power/magnitude circuit. The other T/R filter estimates the level of an interferer, if present, by latching and filtering the largest valued outputs of the power/magnitude circuit.

Abstract: A novel method and apparatus for implementing an overlay adaptive frequency-hopping kernel in a wireless communication system is described. The present inventive method and apparatus selects hopping frequencies based on channel conditions. Hopping frequencies are selected using an inventive overlay adaptive frequency-hopping (OAFH) kernel that maps bad channels to good channels while retaining the pseudo-random properties of the original frequency-hopping sequence. The OAFH kernel uses existing FH kernels to initially select hopping frequencies. If the initially selected hopping frequency has bad channel condition characteristics, the OAFH kernel maps the initially selected hopping frequency to a substitute hopping frequency having good channel condition characteristics.

Abstract: A frequency synthesizer device with a fast off-to-lock time to enable intermittent operation and achieve power savings through automatic control of its On/Off sequence. A relatively fast off-to-lock time is achieved by controlling the sequence of how various components of the synthesizer are reactivated. The voltage controlled oscillator is reactivated, at first operating at its previous operating frequency prior to being deactivated. The phase frequency detector is inhibited while its input signals, a reference signal and a feedback signal, are activated. In a channel hopping communication scheme, the phase frequency detector coarsely tunes the synthesizer to its previous operating frequency, and then jumps to its new operating frequency. Another aspect of the invention provides improved channel locking by guaranteeing that the phase of the feedback signal in a phase lock loop initially lags the phase of the reference frequency signal at the phase frequency detector.

Abstract: The present invention is a method and apparatus for operating a dual-mode radio (DMR) in a wireless communication system. The present invention provides “coexistence” or cooperation of Bluetooth™ and 802.11 devices operating in close proximity to each other within a DMR. The present inventive method and apparatus reduces reception errors and prevents saturation of the Bluetooth™ devices caused by 802.11 transmissions. The present inventive antenna switching method provides a means for coupling multiple antennas to Bluetooth™ and 802.11 transmit and receive devices. Saturation of the Bluetooth™ receive devices is prevented by electrically isolating the Bluetooth™ receive devices from antennas used by the 802.11 device during 802.11 transmissions. The antenna switching apparatus includes a plurality of switches capable of selectively coupling and decoupling first and second antennas to an 802.11 and a Bluetooth™ device.

Abstract: The present invention is a novel method and apparatus for controlling packet data flow in Bluetooth devices. The present Bluetooth flow control method and apparatus reduces data buffer overflow conditions using an inventive flow control technique comprising a dual flow control step and a payload header flow control step. In the dual flow control step, the present inventive method initially enables (i.e., transmits to a transmitting device) both packet header flow control and payload header flow control. In one embodiment, the Bluetooth flow control technique utilizes non-acknowledgment of “nack” commands to enable packet header flow control. In another embodiment, the Bluetooth flow control technique utilizes a packet header flow control bit to enable packet header flow control. In the payload header flow control step, the method determines whether payload header flow control information has been successfully received and, if so, it disables packet header flow control.

Abstract: A novel method and apparatus for calibrating DC offsets in a direct conversion receiver. The present DC offset calibration method and apparatus comprises a direct conversion receiver equipped with a frequency shifter means and a DC offset measurement and correction technique. In accordance with the present invention, DC offsets are calibrated in direct conversion receivers through an inventive method including two steps: a DC offset measurement step and a DC offset correction step. In the DC offset measurement step the frequency of a local oscillation signal (typically generated by a voltage-controlled oscillator (VCO)) is shifted by a selected frequency shift value during the inactive time intervals of the receiver. DC offsets are measured while the frequency of the down-conversion oscillation signal is shifted by the frequency shift value. Before the inactive time interval expires, the frequency of the down-conversion oscillator signal is shifted back to its original value.

Abstract: A method and apparatus for calibrating a voltage-controlled device in a control loop is disclosed. The method and apparatus of the present invention maintains a control voltage of a voltage-controlled device within a high tuning sensitivity range, and thus improves the performance of the voltage-controlled device. The present inventive method and apparatus features a voltage windowing method wherein a high tuning sensitivity window is a subset of the low tuning sensitivity window. In one embodiment, the present invention maintains a control voltage within a predetermined tuning sensitivity window or range. In another embodiment, the present inventive method and apparatus calibrates a PLL that includes multiple VCOs. In yet another embodiment, the present invention calibrates control voltages to account for changes in operating temperature.