In a PAM-N receiver, sampler reference levels, DC offset and AFE gain may be jointly adapted to achieve optimal or near-optimal boundaries for the symbol decisions of the PAM-N signal. For reference level adaptation, the hamming distances between two consecutive data samples and their in-between edge sample are evaluated. Reference levels for symbol decisions are adjusted accordingly such that on a data transition, an edge sample has on average, equal hamming distance to its adjacent data samples. DC offset may be compensated to ensure detectable data transitions for reference level adaptation. AFE gains may be jointly adapted with sampler reference levels such that the difference between a reference level and a pre-determined target voltage is minimized.

Apparatus and methods for front-end systems with reactive loopback are provided. In certain configurations, a front-end system includes an antenna port, a transmit port, a receive port, an antenna switch configured to selectively provide a transmit signal from the transmit port to the antenna port, a low noise amplifier having an input electrically connected to the antenna port and an output electrically connected to the receive port, and a loopback circuit including a reactive loopback impedance and a back switch electrically connected in series between the antenna switch and the receive port. The reactive loopback impedance includes a plurality of capacitors in series with the back switch and operable to provide a portion of the transmit signal to the receive port when the back switch is activated.

An all-digital software-only modem using distributed processing resources of cloud computing is provided. In particular, all processes that were previously supported by purpose built software, firmware, Field Programmable Gate Array (FPGA) hardware description language (HDL) firmware, and an Application Specific Integrated Circuit (ASIC) are in the instant disclosure supported entirely by a High Performance Computing (HPC) server inside a cloud computing environment.

Described herein are front-end architectures and wireless devices that support uplink carrier aggregation and simultaneous MIMO operations in a plurality of band combinations. The front-end architectures include a combination of low-band, mid-band, high-band, MIMO, and uplink carrier aggregation modules to provide the described functionality. The architectures include an antenna switch module coupled to a first antenna and to a second antenna. The second antenna is coupled to the antenna switch module through a diplexer that combines high- and mid-band signals with low-band signals received from a low-band module, the low-band signals coupled to the diplexer without passing through the antenna switch module.

A device includes a digital frontend. The digital frontend is configured to digitally modulate symbols for digital signals of a plurality of channels according to a transmission protocol. Each channel is associated with at least one respective carrier frequency within a transmission bandwidth. The digital frontend is further configured to combine the digital signals to obtain a digital output signal. The device further includes an analog frontend having a digital-to-analog converter configured to convert the digital output signal into an analog output signal. The analog frontend also includes a programmable gain amplifier configured to apply an analog gain to the analog output signal. The device further includes a control logic configured to determine the analog gain based on calibration data indicative of the frequency response of the analog frontend across a transmission bandwidth.

Aspects of the subject disclosure may include, a system for receiving electromagnetic waves that propagate along a transmission medium, generating, according to the electromagnetic waves, signals that convey data and routing information, and providing the signals to a switch that facilitates routing, according to the routing information, a first portion of the data conveyed by the signals to an access point, a second portion of the data conveyed by the signals to a second waveguide system, or a combination thereof. Other embodiments are disclosed.

A communication device for use within a communication system, the device comprising: re-sampling circuitry configured to output re-sampled digital downlink signals by re-sampling digital downlink signals at resample rates based on at least one factor, the re-sampled digital downlink signals having a smaller bandwidth than the digital downlink signals; and framing circuitry configured to multiplex the re-sampled digital downlink signals and to generate a first frame that includes the re-sampled digital downlink signals as framed data for transport to one or more remotely located communication devices of the communication system, wherein the one or more remotely located communication devices of the communication system are configured to transmit radio frequency signals using at least one antenna, wherein the transmitted radio frequency signals are derived from the framed data of the first frame received from the communication device.

Aspects of the subject disclosure may include, a system for receiving first electromagnetic waves that propagate along a transmission medium, where the first electromagnetic waves convey first data, generating first signals by frequency-shifting the first electromagnetic waves without demodulating the first electromagnetic waves, and providing the first signals to one or more modems that facilitate demodulation of the first signals to second signals, and distribution of a first portion of data conveyed by the second signals to an access point, a second portion of the data to a second waveguide system, or combinations thereof. Other embodiments are disclosed.

Aspects of the subject disclosure may include, a first waveguide system for obtaining instructions that reconfigures operations thereof, receiving first electromagnetic waves propagating along a transmission medium without requiring an electrical return path, where the first electromagnetic waves convey first data. The first waveguide system can further facilitate processing the first electromagnetic waves, according to the instructions, to selectively generate repeated electromagnetic waves for delivery to a second waveguide system, regenerated electromagnetic waves for delivery to the second waveguide system, first signals for delivery to a routing device, or any combinations thereof. Other embodiments are disclosed.

Aspects of the subject disclosure may include, a system for receiving second signals from a switch responsive to the switch receiving first signals a first waveguide system, wherein the first waveguide system facilitates generating the first signals responsive to receiving first electromagnetic waves that propagate along a transmission medium. The system further facilitates selecting a communication device according to the second signals, and transmitting a first wireless signal directed to the communication device, wherein the first wireless signal conveys first data supplied by the second signals. Other embodiments are disclosed.