A method and a system for processing uplink signals in cloud radio access networks are disclosed The system comprising a baseband unit and a number of remote radio heads. The baseband unit and the remote radio heads are connected through fronthaul links. When one remote radio head receives a signal transmitted from a user equipment, the remote radio head first encodes the received signal according to a post-coding matrix, then quantizes the encoded signal according to a number of quantization bits allocated to the user equipment, and finally transmits the quantized signal to the baseband unit.

A method for quantizing data representative of a radio signal received by a radio antenna of a mobile network. The method includes: demodulating the radio signal received by the antenna, providing a demodulated signal; scalar quantizing each value of the demodulated signal using a quantization table selected according to a channel coding level used to transmit the radio signal, providing a quantized demodulated signal; and transmitting the quantized demodulated signal to a channel decoding module.

A method performed by an encoder of a base station system, for handling a data stream for transmission over a transmission connection between a remote unit and a base unit of the base station system, the remote unit being arranged to transmit wireless signals to, and receive from, mobile stations. The method comprises quantizing a plurality of IQ samples, converting the quantized plurality of IQ samples to IQ predictions, calculating per sample a difference between the quantized plurality of IQ samples and the IQ predictions in order to create IQ prediction errors. The method further comprises quantizing the IQ predictions or the IQ prediction errors, entropy encoding the IQ prediction errors and sending the entropy encoded IQ prediction errors over the transmission connection to a decoder of the base station system. The method can be performed by a decoder.

Provided are a multilevel output drive circuit and method. The circuit includes: a signal selection module, configured to selectively output a signal to be transmitted of a corresponding channel according to an external input signal; a weight generation module, configured to generate weight data according to a weight of an output eye diagram, wherein the weight of the output eye diagram and the weight data are multi-bit binary data; a coefficient transfer module, configured to perform weight control on the signal to be transmitted according to the weight data and generate data containing weight information; and a weight adjustment and data outputting module, configured to perform weight adjustment and pulse amplitude modulation calculation according to weight adjustment control data, the signal to be transmitted and the data containing weight information, and generate PAM4 data.

A method, an apparatus and a system to measure nonlinear correlation parameters of a nonlinear device, a processor to, perform band-stop filtering on a signal to be measured to generate a notch signal, and calculate a first nonlinear correlation parameter of the nonlinear device when the signal to be measured is transmitted according to a first output signal of the nonlinear device after the notch signal is input into the nonlinear device; calculate gain compression correction coefficients according to a second output signal of the nonlinear device after the first input signal is input into the nonlinear. The first input signal and the signal to be measured may have identical power and different signal probability distribution. The processor is to correct the first nonlinear correlation parameter according to the gain compression correction coefficients to obtain a second nonlinear correlation parameter of the nonlinear device when the signal to be measured is transmitted.

Provided is a precoding method for generating, from a plurality of baseband signals, a plurality of precoded signals to be transmitted over the same frequency bandwidth at the same time, including the steps of selecting a matrix F[i] from among N matrices, which define precoding performed on the plurality of baseband signals, while switching between the N matrices, i being an integer from 0 to N−1, and N being an integer at least two, generating a first precoded signal z1 and a second precoded signal z2, generating a first encoded block and a second encoded block using a predetermined error correction block encoding method, generating a baseband signal with M symbols from the first encoded block and a baseband signal with M symbols the second encoded block, and precoding a combination of the generated baseband signals to generate a precoded signal having M slots.

Selection of equalization coefficients to configure a communications link between a receiver in a host system and a transmitter in an optical or electrical communication module is performed by a management entity with access to management registers in the receiver and transmitter. Continuous modification of the selected equalization coefficients is enabled on the communications link after the communications link is established to handle varying operating conditions such as temperature and humidity.

A system for transmitting a value via a pulse-width-modulated signal, comprises a transmitter and a receiver. The transmitter is configured for detecting the value and for outputting a pulse-width-modulated signal having a pulse width which represents the value or a range around the value. The receiver is configured for deriving the value or the range from the pulse-width-modulated signal, by evaluating the pulse width. The transmitter is furthermore configured to read back the emitted pulse-width-modulated signal and to check whether the value or the range can be derived from the emitted pulse-width-modulated signal, and, if the value or the range cannot be derived, to output an error signal to the receiver.

A network node determines parameters indicating a compression function for compressing downlink channel estimates, and a decompression function. The network node transmits the parameters, receives compressed downlink channel estimates, and decompresses the compressed downlink channel estimates using the decompression function. A terminal device receives the parameters, forms the compression function, compresses downlink channel estimates using the compression function, and transmits the compressed downlink channel estimates. The compression function comprises a first function formed based on at least some of the parameters, a second function which is non-linear, and a quantizer. The first function is configured to receive input data, and to reduce a dimension of the input data. The decompression function comprises a first function configured to receive input data and provide output data in a higher dimensional space than the input data, and a second function which is non-linear.

Methods and devices implementing a combination of multi-dimensional pulse position modulation (PPM) with wavelength division multiplexing (WDM) or wavelength division multiplexing multiple access (WDMA) for long range space communications are disclosed. The described multi-dimensional PPM scheme can use the laser wavelength and/or polarization as the additional dimension(s) to the time dimension. Through examples it is shown that the disclosed teachings result in a higher photon information efficiency. Various exemplary embodiments are also presented to highlight the applications benefiting from the disclosed methods and devices.