Various embodiments of the present invention solve the problem of generating intermediate-time information useable to drive ZFE adaptation (for example, in connection with a digital receiver). Further, various embodiments of the present invention increase flexibility by enabling user-specified over-peaking and/or under-peaking (i.e. configurable equalizer tuning) with respect to a ZFE convergence (or lock) criterion.

A transmitter/receiver apparatus and method provide adaptive data rate fading compensation that utilize dual-polarization transmissions at a constant modulation-symbol rate over a forward-scatter radio link and that employ adaptive receiver techniques that operate efficiently at the noisy uncoded signal-to-noise ratio threshold of present-day forward-error correction codes over the range of multipath widths in such forward-scatter environments. The dual-polarization transmissions support both dual transmission and dual diversity configurations. The adaptive receiver techniques include adaptive channel matched filtering and adaptive equalizing at the modulation-symbol rate.

A method and system for maximizing throughput and minimizing latency in a communication system that supports heterogeneous links is presented. The communication system supports a primary link and an alternate link, and the method and system leverage the alternate link to reduce the overhead transmitted over the primary link, thereby increasing throughput and reducing end-to-end latency. The higher latency alternate link provides a delayed version of an information signal that corresponds to a portion of the information signal that is transmitted on the primary link. The received samples from the primary and alternate links may be used to equalize subsequent portions of the information signal received over the primary link, and may also be used for synchronization, timing recovery, DC offset removal, I/Q imbalance compensation, and frequency-offset estimation.

System and method of timing recovery for recovering a clock signal by using adaptive channel response estimation. The channel response estimation in the timing recovery loop is dynamically adapted to the current channel response that varies over time. More particularly, the channel estimation coefficients used in a channel estimator can be adapted based on an error signal representing the difference between a received signal at the timing recovery loop and an estimated signal output from a channel estimator. Further, to prevent undesirable interaction between the channel estimator and the overall timing recovery loop with respect to clock phase recovery, the adaptation of channel estimation can be controlled in terms of speed or time so as to reduce or eliminate the channel estimator's effect on clock phase correction.

An input signal is sampled at a current sampling phase by a sampler device of a receiver device. The sampled input signal is equalized by an adaptive equalizer of the receiver device. One or more parameters of the adaptive equalizer are adapted, based on the equalized input signal, under one or more adaptation constraints. Phase gradient information indicative of an offset of the current sampling phase from an optimal sampling phase is determined, and the one or more adaptation constraints of the adaptive equalizer are updated based on the phase gradient information to move the current sampling phase towards the optimal sampling phase.

A signal detection unit detects, from a baseband signal of a received radio wave, two types of fixed signal sections that have different communication information and are present in sufficiently shorter time than a time period in which influence of fading fluctuates, and designate the detected two types of fixed signal sections as an information-1 section and an information-2 section. An information-1 section signal processing unit clips the information-1 section from the baseband signal, and performs Fourier transform on the clipped information-1 section. An information-2 section signal processing unit clips the information-2 section from the baseband signal, and performs Fourier transform on the clipped information-2 section. A feature value computation unit computes a feature value, based on an output of the information-1 section signal processing unit and an output of the information-2 section signal processing unit.

An apparatus for signal modulation in a point-to-multipoint optical network is configured to modulate a single-wavelength carrier wave before distribution towards optical receivers of a first type adapted for intensity detection and a second type adapted for optical field detection. The apparatus includes a first module configured to modulate the carrier wave by varying the intensity of the carrier wave to represent data intended for the first type of receivers, and by controlling the phase and/or polarization of the carrier wave during selected periods. The apparatus includes a second module configured to modulate the carrier wave by varying the phase and/or polarization of the carrier wave to represent data intended for the second type of receivers, and by varying the intensity of the carrier wave during selected periods.

A intelligent backhaul radio is disclosed that is compact, light and low power for street level mounting, operates at 100 Mb/s or higher at ranges of 300 m or longer in obstructed LOS conditions with low latencies of 5 ms or less, can support PTP and PMP topologies, uses radio spectrum resources efficiently and does not require precise physical antenna alignment.

A method (200) for channel estimation includes receiving (201) a receive symbol (206) comprising: a plurality of interfering transmissions from: a first transmit symbol (202), the first transmit symbol (202) comprising a plurality of unknown modulated symbols interleaved with a plurality of known modulated symbols and a second transmit symbol (204), the second transmit symbol (204) comprising a plurality of unknown modulated symbols interleaved with a plurality of known modulated symbols, wherein the plurality of transmissions from the first transmit symbol (202) and the second transmit symbol (204) are a plurality of transmissions of different time instances; and estimating (203) a channel based on the receive symbol (206) and a plurality of estimates of the first transmit symbol (202) and the second transmit symbol (204).

A continuous time linear equalizer comprises an input of a first equalizer path configured to receive a first differential input signal; an input of a second equalizer path configured to receive a second differential input signal; a first programmable load capacitor coupled to an output of the first equalizer path; a second programmable load capacitor coupled to an output of the second equalizer path; and a programmable source capacitor coupled between the first equalizer path and the second equalizer path.