Flexible structured-pipelined CORDIC techniques efficiently perform various CORDIC operations and support different parameters for MIMO MEQ processing. The structured-pipelined CORDIC techniques simplify signal processing flow, unify input requirements and output delay, and simplify integration. Look-up table techniques provide quick generation of control signals, reduce design and verification efforts, and facilitate design automation. In addition, the structured-pipelined CORDIC techniques are conducive to hardware sharing and reuse. The structured-pipelined CORDIC techniques reduce integrated circuit area and power consumption.

A distributed radio frequency communication system includes a remote radio unit (RRU and a baseband unit (BBU) and facilitates communication between a wireless terminal and a core network. The RRU receives a radio frequency signal from a wireless terminal and convert the radio frequency signal to digital baseband samples using receiver circuitry and an analog-to-digital converter. The RRU then adaptively compresses the digital baseband samples, using adaptive compression circuitry, to create fronthaul uplink information, and sends the fronthaul uplink information over a fronthaul link to the BBU using an adaptive fronthaul protocol. The RRU also receives fronthaul downlink information over a fronthaul link from the BBU using an adaptive fronthaul protocol and generates frequency-domain samples, based on the fronthaul downlink information received. It then creates time-domain baseband samples from the frequency-domain samples and converts the time-domain baseband samples into a radio frequency signal to send to the wireless terminal.

A distributed radio frequency communication system facilitates communication between a wireless terminal and a core network. The system includes a remote radio unit (RRU) coupled to at least one antenna to communicate with the wireless terminal. The RRU includes electronic circuitry to perform at least a first portion of a first-level protocol of a radio access network (RAN) for communicating between the wireless terminal and the core network. The system also includes a baseband unit (BBU) coupled to the core network, and configured to perform at least a second-level protocol of the RAN. A fronthaul link is coupled to the BBU and the RRU. The fronthaul link utilizes an adaptive fronthaul protocol for communication between the BBU and the RRU. The adaptive fronthaul protocol has provisions for adapting to conditions of the fronthaul link and radio network by changing the way data is communicated over the fronthaul link.

A stable modulation-index Bluetooth (BT) transmitter circuit includes a baseband modulator circuit to generate a baseband BT signal. An intermediate frequency (IF) circuit adds a frequency offset to the baseband BT signal with a low IF and generates a modulated signal. A digital-to-analog converter (DAC) converts the modulated signal to an analog signal that is upconverted using a voltage controlled oscillator (VCO). The baseband frequency offset is subtracted from the corresponding radio-frequency (RF) signal by reducing the local oscillator (LO) frequency by the same amount. This has the effect of modulating the carrier leakage away from the center frequency of the transmitted BT signal. The resulting RF signal is transmitted to a receiver.

A stable modulation-index Bluetooth (BT) transmitter circuit includes a baseband modulator circuit to generate a baseband BT signal. An intermediate frequency (IF) circuit adds a frequency offset to the baseband BT signal with a low IF and generates a modulated signal. A digital-to-analog converter (DAC) converts the modulated signal to an analog signal that is upconverted using a voltage controlled oscillator (VCO). The baseband frequency offset is subtracted from the corresponding radio-frequency (RF) signal by reducing the local oscillator (LO) frequency by the same amount. This has the effect of modulating the carrier leakage away from the center frequency of the transmitted BT signal. The resulting RF signal is transmitted to a receiver.

Techniques and systems for extending the capture range of frequency offset error detection are described. For instance, the present disclose describes efficient frequency estimation structures (e.g., zero crossing minimum/maximum (min/max) structures) that may extend carrier frequency offset error capture range by running a bank (e.g., a set) of parallel capture range structures trialing different frequency errors. In some aspects, a set of frequency offset estimation circuits and a set of correlation circuits (e.g., 1-bit correlators) may be used on parallel streams to perform correlation operations on each branch of a received bit stream to determine correlations with known preamble patterns (e.g., to accurately estimate large frequency offset errors).

Embodiments of a station (STA) and method for communication in accordance with phase noise compensation are generally described herein. The STA may determine, based at least partly on one or more operational parameters, whether to perform phase noise compensation of data symbols of a received protocol data unit (PDU). For instance, the STA may compare the operational parameters with one or more thresholds. The STA may further determine a method of phase noise compensation based at least partly on one or more operational parameters. As an example, the STA may determine a type of interpolation to be used for an interpolation of phase noise estimates of pilot symbols to determine phase noise estimates of data symbols. Example operational parameters may include a signal quality metric, a carrier frequency offset (CFO) measurement and/or modulation and coding scheme (MCS).

A method for determining an angle of arrival (AOA) of a received signal is disclosed, comprising: generating a baseband information signal by mixing a received signal with a local oscillator (LO) signal, the received signal being an in-phase signal and quadrature signal uncorrelated with each other and derived from different input data sets; obtaining baseband signal samples of the baseband information signal having an in-phase signal sample and a quadrature signal sample; determining a transmitter phase offset based on an estimated correlation between the in-phase signal samples and the quadrature signal samples; performing a plurality of phase measurements using a plurality of antennas to obtain a plurality of phase measurements; correcting the plurality of phase measurements based on the transmitter phase offset to produce a plurality of corrected phase measurement; and calculating an AOA of the received signal based on the difference between the plurality of corrected phase measurements.

A method is disclosed for synchronization, comprising obtaining baseband signal samples of a baseband information signal having an in-phase signal sample and a quadrature signal sample, the baseband information signal having been generated by mixing a received modulated carrier signal with a local oscillator (LO) signal having an LO frequency, the modulated carrier signal being an in-phase signal and quadrature signal having a substantially uncorrelated nature and derived from different input data sets; determining an offset frequency rotation based on an estimated residual correlation between the in-phase signal samples and the quadrature signal samples; and, deriving synchronization information from the offset frequency rotation, wherein the received modulated carrier signal is a quadrature-modulated signal with arbitrary orthogonal in-phase and quadrature signal components.

A distributed radio frequency communication system facilitates communication between a wireless terminal and a core network. The system includes a remote radio unit (RRU) coupled to at least one antenna to communicate with the wireless terminal. The RRU includes electronic circuitry to perform at least a first portion of a first-level protocol of a radio access network (RAN) for communicating between the wireless terminal and the core network. The system also includes a baseband unit (BBU) coupled to the core network, and configured to perform at least a second-level protocol of the RAN. A fronthaul link is coupled to the BBU and the RRU. The fronthaul link utilizes an adaptive fronthaul protocol for communication between the BBU and the RRU. The adaptive fronthaul protocol has provisions for adapting to conditions of the fronthaul link and radio network by changing the way data is communicated over the fronthaul link.