A radio-frequency module includes a first transmitter-and-receiver that transmits and receives a signal in a first band, and a second transmitter-and-receiver that transmits and receives a signal in a second band higher than the first band. The first transmitter-and-receiver includes a first amplifier circuit and a first separator circuit and the second transmitter-and-receiver includes a second amplifier circuit and a second separator circuit. The first separator is located on a substrate between the first amplifier circuit and the second separator circuit, such that the first separator circuit is spatially interposed between the first amplifier circuit and the second separator circuit.

A wireless network includes a tunable RF transmitter in wireless communication with a master node to transmit at a first slave frequency; a tunable RF receiver in wireless communication with the master node to receive at a second slave frequency; and an RF oscillator to communicate with the RF receiver and the RF transmitter an RF oscillator frequency to determine and tune the first and second slave frequencies. The RF oscillator is configured to receive calibration information including time information or frequency information, or both, from a reference node. The RF oscillator frequency of the RF oscillator is tuned based on the calibration information from the reference node to enable communication between the slave node and the master node at the tuned RF oscillator frequency.

A wireless network includes a tunable RF transmitter in wireless communication with a master node to transmit at a first slave frequency; a tunable RF receiver in wireless communication with the master node to receive at a second slave frequency; and an RF oscillator to communicate with the RF receiver and the RF transmitter an RF oscillator frequency to determine and tune the first and second slave frequencies. The RF oscillator is configured to receive calibration information including time information or frequency information, or both, from a reference node. The RF oscillator frequency of the RF oscillator is tuned based on the calibration information from slave node and the master node at the tuned RF oscillator the reference node to enable communication between the frequency.

A wireless network includes a tunable RF transmitter in wireless communication with a master node to transmit at a first slave frequency; a tunable RF receiver in wireless communication with the master node to receive at a second slave frequency; and an RF oscillator to communicate with the RF receiver and the RF transmitter an RF oscillator frequency to determine and tune the first and second slave frequencies. The RF oscillator is configured to receive calibration information including time information or frequency information, or both, from a reference node. The RF oscillator frequency of the RF oscillator is tuned based on the calibration information from the reference node to enable communication between the slave node and the master node at the tuned RF oscillator frequency.

An electronic device may be provided with wireless circuitry and control circuitry. The wireless circuitry may include an antenna with an inverted-F antenna resonating element formed from portions of a peripheral conductive electronic device housing structure and may have an antenna ground that is separated from the antenna resonating element by a gap. The antenna may include a first adjustable component coupled between the antenna resonating element arm and the antenna ground on a first side of the antenna feed and a second adjustable component coupled between the antenna resonating element arm and the antenna ground on a second side of the antenna feed. Control circuitry in the electronic device may adjust the first and second adjustable components between a first tuning mode, a second tuning mode, and a third tuning mode.

An electronic device may be provided with wireless circuitry and control circuitry. The wireless circuitry may include an antenna with an inverted-F antenna resonating element formed from portions of a peripheral conductive electronic device housing structure and may have an antenna ground that is separated from the antenna resonating element by a gap. The antenna may include a first adjustable component coupled between the antenna resonating element arm and the antenna ground on a first side of the antenna feed and a second adjustable component coupled between the antenna resonating element arm and the antenna ground on a second side of the antenna feed. Control circuitry in the electronic device may adjust the first and second adjustable components between a first tuning mode, a second tuning mode, and a third tuning mode.

A wireless network includes a tunable RF transmitter in wireless communication with a master node to transmit at a first slave frequency; a tunable RF receiver in wireless communication with the master node to receive at a second slave frequency; and an RF oscillator to communicate with the RF receiver and the RF transmitter an RF oscillator frequency to determine and tune the first and second slave frequencies. The RF oscillator is configured to receive calibration information including time information or frequency information, or both, from a reference node. The RF oscillator frequency of the RF oscillator is tuned based on the calibration information from the reference node to enable communication between the slave node and the master node at the tuned RF oscillator frequency.

Methods and apparatus that support controlled transmission and directional reception of RTS and/or CTS messages, are described. Controlled transmission may include transmitting a same RTS message multiple times in the same direction and/or transmitting an RTS message with a length that is multiple times longer than a standard RTS message. In an aspect, a receiver may determine spatial directions of a plurality of transmitters including a first transmitter and at least one other transmitter, and may perform a beam sweep in the determined spatial directions for receiving one or more RTS messages. A transmitter may determine that a receiver is to perform a beam sweep in K different spatial directions, and may transmit a same RTS message for a data transmission K times in the same direction or an RTS message with a length approximately K times longer than a standard RTS message, during a duration of the beam sweep.

Methods and apparatus that support controlled transmission and directional reception of RTS and/or CTS messages, are described. Controlled transmission may include transmitting a same RTS message multiple times in the same direction and/or transmitting an RTS message with a length that is multiple times longer than a standard RTS message. In an aspect, a receiver may determine spatial directions of a plurality of transmitters including a first transmitter and at least one other transmitter, and may perform a beam sweep in the determined spatial directions for receiving one or more RTS messages. A transmitter may determine that a receiver is to perform a beam sweep in K different spatial directions, and may transmit a same RTS message for a data transmission K times in the same direction or an RTS message with a length approximately K times longer than a standard RTS message, during a duration of the beam sweep.

A radio-frequency module includes a first transmitter-and-receiver that transmits and receives a signal in a first band, and a second transmitter-and-receiver that transmits and receives a signal in a second band higher than the first band. The first transmitter-and-receiver includes a first amplifier circuit and a first separator circuit and the second transmitter-and-receiver includes a second amplifier circuit and a second separator circuit. The first separator is located on a substrate between the first amplifier circuit and the second separator circuit, such that the first separator circuit is spatially interposed between the first amplifier circuit and the second separator circuit.