Provided is a communication system using a space division multi-user multiple input multiple output (SD-MIMO) communication method. A transmission apparatus may transmit, to each of terminals included within a coverage, common control information commonly transmitted to the terminals and individual control information individually transmitted to each of the terminals. The transmission apparatus does not precode the common control information and transmits the non-precoded common control information. The transmission apparatus precodes the individual control information and transmits the precoded individual control information.

Various embodiments include a power amplifier with crest factor reduction embodied by first circuitry for producing a correlated out-of-band noise signal for controlling the adjacent channel leakage ratio (ACLR) of a communication device; and second circuitry for providing an output signal for controlling the error vector magnitude (EVM) of a digital radio. The ACLR and the EVM are concurrently individually controllable. Additional apparatus is described.

Various embodiments include a power amplifier with crest factor reduction embodied by first circuitry for producing a correlated out-of-band noise signal for controlling the adjacent channel leakage ratio (ACLR) of a communication device; and second circuitry for providing an output signal for controlling the error vector magnitude (EVM) of a digital radio. The ACLR and the EVM are concurrently individually controllable. Additional apparatus is described.

System for passively classifying a signal as a user equipment (UE) generated uplink communication in accordance with in an LTE communication standard includes a radio frequency receiver and a computer processor operatively coupled to the receiver. The system evaluates physical parameters of the RF signals and obtains an extracted bit sequence contained in a time slot in which a Demodulation Reference Signal (DRS) would be normally transmitted. The extracted bit sequence information is compared to a plurality of known bit sequences specified for DRS in an LTE uplink communication.

A local oscillator outputs a local oscillator signal that provides an upper side heterodyne mode or a lower side heterodyne mode for a received RF signal. A first converter converts the received RF signal into an IF signal, based on the local oscillator signal output from the local oscillator. An FM detector subjects the IF signal produced by conversion to detection. A first measurement unit measures a signal intensity of the IF signal before the IF signal is input to the FM detector. A second measurement unit measures a squelch voltage of a signal detected by the FM detector. A controller that controls the local oscillator based on the signal intensity measured by the first measurement unit and the squelch voltage measured by the second measurement unit.

Various aspects of the disclosure relate to the selection and use of modulation and coding scheme (MCS) values. For example, a first MCS table may be used for a first condition and a second MCS table used for a second condition. The disclosure relates in some aspects to inter-device signaling that indicates which MCS table is to be used for communication between the devices.

Various aspects of the disclosure relate to the selection and use of modulation and coding scheme (MCS) values. For example, a first MCS table may be used for a first condition and a second MCS table used for a second condition. The disclosure relates in some aspects to inter-device signaling that indicates which MCS table is to be used for communication between the devices.

In some implementations, an automatic gain control (AGC) circuit comprises: a pre-divider circuit operable to pre-divide an input signal according to a pre-divider circuit setting and output a pre-divided signal; a pre-amplifier operable to pre-amplify the pre-divided signal and output a pre-amplified signal; a post-divider circuit operable to post-divide the pre-amplified signal according to a post-divider circuit setting; an analog-to-digital converter (ADC) operable to generate a digital data stream from the post-divided signal; logic operable to sample the digital data stream; determine a pre-divider circuit setting and a post-divider circuit setting based on the sampled data stream; set the pre-divider circuit and the post-divider circuit based on the determined settings; and generate a received signal strength value based on the pre-divider circuit setting and the post-divider circuit setting.

A transmitter, a transmission system and a transmission method whereby AM-PM distortions can be compensated with high accuracy without affecting the functions of a predistortor, a ΔΣ modulator and so on. The transmitter includes: a baseband signal generation circuit that outputs the amplitude value and phase value of a baseband signal; a ΔΣ modulation circuit that performs a ΔΣ modulation of the outputted amplitude and phase values to output a pulse signal train; a power supply modulation circuit that supplies, to a pre-stage amplifier, a voltage determined in accordance with the outputted amplitude value; the pre-stage amplifier and a post-stage amplifier that amplify the outputted pulse signal train; and a filter circuit that generates an output signal from the pulse signal train as amplified and outputs the output signal. The power supply modulation circuit determines the voltage for canceling a phase error occurring in the post-stage amplifier.

A transmitter, a transmission system and a transmission method whereby AM-PM distortions can be compensated with high accuracy without affecting the functions of a predistortor, a ΔΣ modulator and so on. The transmitter includes: a baseband signal generation circuit that outputs the amplitude value and phase value of a baseband signal; a ΔΣ modulation circuit that performs a ΔΣ modulation of the outputted amplitude and phase values to output a pulse signal train; a power supply modulation circuit that supplies, to a pre-stage amplifier, a voltage determined in accordance with the outputted amplitude value; the pre-stage amplifier and a post-stage amplifier that amplify the outputted pulse signal train; and a filter circuit that generates an output signal from the pulse signal train as amplified and outputs the output signal. The power supply modulation circuit determines the voltage for canceling a phase error occurring in the post-stage amplifier.