Communications system using adaptive frequency notching

A communications device for communications systems, comprising:

• a receiver circuit configured to connect to a transmission channel and configured to determine a signal power of a first communications signal received over the transmission channel, the receiver circuit including a noise detection circuit configured to measure noise above a predefined noise level in the communications signal during reception of the communications signal;
• a transmitter circuit configured to connect to the transmission channel and configured to transmit a first gain control signal separate from the first communications signal over the transmission channel;
• and
• a controller circuit connected to the receiver circuit and the transmitter circuit and configured to initiate transmission of the first gain control signal, if a ratio between a signal power of the first communications signal and the predefined noise level exceeds a first predetermined threshold level given by the dynamic range of an analog digital converter included in the receiver circuit and configured to convert the received communications signal.

A communication device for communications systems, comprising:

• a receiver circuit configured to connect to a transmission channel and configured to receive a gain control signal over the transmission channel;
• a transmitter circuit configured to connect to the transmission channel and configured to transmit a communications signal that is separate from the gain control signal over the transmission channel, wherein a gain of the communications signal is adjustable;
• and
• a controller circuit connected to the receiver circuit and the transmitter circuit and configured to control the gain in response to a received gain control signal to generate a signal that power ensures safe reception of the communications signal and facilitates, during reception of the communications signal, a measurement of noise of a predefined noise level.

A method of operating a communications system, comprising:

• determining, at a receiver circuit, a signal power of a communications signal received via a transmission channel;
• transmitting a gain control signal that is separate from the communications signal via the transmission channel;
• adjusting, at a transmitter circuit, a signal power for the communications signal in response to the gain control signal such that a ratio of the communications signal level and a predetermined noise level is equal to or lower than a dynamic range of an analog digital converter included in the receiver circuit and configured to convert the communications signal;
• and
• scanning, at the receiver circuit, and during simultaneous reception of a communications signal, a receiver frequency range for a notch frequency band containing noise above the predetermined noise level.

A method of operating a communications system, comprising:

• transmitting a communications signal including predetermined training symbols suitable for channel estimation from a first to a second communications device via a communications channel;
• scanning, at the second communications device and during simultaneous reception of the communications signal, a receiver frequency range for a notch frequency band containing noise above a predetermined noise level;
• and
• transmitting, via the communications channel, a gain control signal that is separate from the communications signal from the second communications device based on the scanning step,
• wherein the receiver frequency range is scanned during transmission of the predetermined training symbols, and
• successive training symbols are transmitted at different temporary distances to each other.

A method of operating a communications system, comprising:

• transmitting a communications signal including payload data symbols suitable for channel estimation from a first to a second communications device via a communications channel;
• scanning, at the second communications device and during simultaneous reception of the communications signal, a receiver frequency range for a notched frequency band containing noise above a predetermined noise level;
• and
• transmitting, via the communications channel, a gain control signal that is separate from the communications signal from the second communications device to the first communications device based on the scanning step,
• wherein the receiver frequency range is scanned during transmission of the payload data symbols, and
• successive payload data symbols are transmitted at different temporary distances to each other.