An electronic device may include wireless circuitry with a baseband processor, a transceiver circuit, a front-end module, and an antenna. The front-end module may include amplifier circuitry such as a low noise amplifier for amplifying received radio-frequency signals. The amplifier circuitry is operable in a non-carrier-aggregation mode and a carrier aggregation mode. The amplifier circuitry may include an input transformer that is coupled to multiple amplifier stages such as a common gate amplifier stage, a cascode amplifier stage, and a common source amplifier stage. The common gate amplifier stage may include switches for selectively activating a set of cross-coupled capacitors to help maintain input impedance matching in the non-carrier-aggregation mode and the carrier-aggregation mode. The common source amplifier stage may include additional switches for activating and deactivating the common source amplifier stage to help maintain the gain in the non-carrier-aggregation mode and the carrier-aggregation mode.

A bridge combiner can be implemented as a coupling circuit that includes a common node and configured to couple the common node to a first group of filters through a first path and to couple the common node to a second group of one or more filters through a second path. The coupling circuit can include a resonator such that an impedance provided by each filter of the first group for a signal in each band of the second group results in the signal being sufficiently excluded from the first path, and such that an impedance provided by each filter of the second group for a signal in each band of the first group results in the signal being sufficiently excluded from the second path.

A bridge combiner can be implemented as a coupling circuit that includes a common node and configured to couple the common node to a first group of filters through a first path and to couple the common node to a second group of one or more filters through a second path. The coupling circuit can include a resonator such that an impedance provided by each filter of the first group for a signal in each band of the second group results in the signal being sufficiently excluded from the first path, and such that an impedance provided by each filter of the second group for a signal in each band of the first group results in the signal being sufficiently excluded from the second path.

Wireless communication devices (UEs) may include multiple receive (RX) chains and associated antennas, and at least one transmit (TX) chain co-located with one of the RX chains. The UE may track instant fading of the antenna gain(s) during reception of packets from an associated access point (AP) device to which the UE intends to transmit packets. The UE may also track long term antenna gain(s), using any packets received at the multiple RX chains within the UE. At a switching occasion, a decision is made by the UE whether to switch antennas. If the instant fading detection is based on packets received no later than a specified time period prior to the switching occasion, then the UE may make the switching decision based on the results of the instant fading tracking. Otherwise, the UE may make the switching decision based on the results of the long term antenna gain tracking.

Wireless communication devices (UEs) may include multiple receive (RX) chains and associated antennas, and at least one transmit (TX) chain co-located with one of the RX chains. The UE may track instant fading of the antenna gain(s) during reception of packets from an associated access point (AP) device to which the UE intends to transmit packets. The UE may also track long term antenna gain(s), using any packets received at the multiple RX chains within the UE. At a switching occasion, a decision is made by the UE whether to switch antennas. If the instant fading detection is based on packets received no later than a specified time period prior to the switching occasion, then the UE may make the switching decision based on the results of the instant fading tracking. Otherwise, the UE may make the switching decision based on the results of the long term antenna gain tracking.

According to one embodiment, a wireless communication device includes a transmitter configured to transmit a first field containing information to identify a plurality of wireless communication terminals, and configured to multiplex and transmit a plurality of second fields in each of which a first frame containing an address of any of the wireless communication terminals is set; and a controller configured to determine, for the first frames, values pertaining to lengths of durations to suppress access to a wireless medium to the wireless communication terminal having an address different from the address contained in each of the first frames. The transmitter is configured to set the values in the first frames, the second fields, or the first field. The controller is configured to determine the values so that the durations have an end at an identical time.

A system and method that scrambles the phase characteristic of a carrier signal are described. The scrambling of the phase characteristic of each carrier signal includes associating a value with each carrier signal and computing a phase shift for each carrier signal based on the value associated with that carrier signal. The value is determined independently of any input bit value carried by that carrier signal. The phase shift computed for each carrier signal is combined with the phase characteristic of that carrier signal so as to substantially scramble the phase characteristic of the carrier signals. Bits of an input signal are modulated onto the carrier signals having the substantially scrambled phase characteristic to produce a transmission signal with a reduced PAR.

A system and method that scrambles the phase characteristic of a carrier signal are described. The scrambling of the phase characteristic of each carrier signal includes associating a value with each carrier signal and computing a phase shift for each carrier signal based on the value associated with that carrier signal. The value is determined independently of any input bit value carried by that carrier signal. The phase shift computed for each carrier signal is combined with the phase characteristic of that carrier signal so as to substantially scramble the phase characteristic of the carrier signals. Bits of an input signal are modulated onto the carrier signals having the substantially scrambled phase characteristic to produce a transmission signal with a reduced PAR.

An apparatus may include a microprocessor and a wireless communication interface configured to perform at least one of receiving a first radio signal or transmitting a second radio signal. The microprocessor may be configured to execute at least one of a base-band encoder software program or a base-band decoder software program. The apparatus may be further configured to execute a wireless communication protocol selector software program that may be configured to optimize a value of a user-defined criterion in order to dynamically select at least one of a wireless communication network, a wireless communication protocol, and a parameter of a wireless communication protocol.

An apparatus may include a microprocessor and a wireless communication interface configured to perform at least one of receiving a first radio signal or transmitting a second radio signal. The microprocessor may be configured to execute at least one of a base-band encoder software program or a base-band decoder software program. The apparatus may be further configured to execute a wireless communication protocol selector software program that may be configured to optimize a value of a user-defined criterion in order to dynamically select at least one of a wireless communication network, a wireless communication protocol, and a parameter of a wireless communication protocol.