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.

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 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.

This application provides a data sending method and apparatus. The method includes: A node generates a first modulation symbol corresponding to a first modulation scheme. The node quantizes the first modulation symbol to obtain a target symbol. The target symbol corresponds to one of a plurality of constellation points of a second modulation scheme. The node preprocesses the target symbol to obtain to-be-sent data. The preprocessing includes one or more of layer mapping, antenna port mapping, precoding, or transform precoding. The node maps the to-be-sent data to a physical resource, and sends the to-be-sent data by using the physical resource.

A serial receiver combines continuous-time equalization, analog interleaving, and discrete-time gain for rapid, efficient data reception and quantization of a serial, continuous-time signal. A continuous-time equalizer equalizes a received signal. A number N of time-interleaved analog samplers sample the equalized continuous-time signal to provide N streams of analog samples transitioning at rate reduced by 1/N relative to the received signal. A set of N discrete-time variable-gain amplifiers amplify respective streams of analog samples. A quantizer then quantizes the amplified streams of analog samples to produce a digital signal.

An optical communication system includes a transmission side system for multi-level pulse amplitude modulation (PAM) and a corresponding receiver side system, where the transmission side comprises a laser source providing an optical beam, a signal source of electrical signals to be modulated onto the optical beam, and a modulator coupled to the laser source and the signal source to modulate the electrical signals onto the optical beam using amplitude modulation and at least four signal levels, wherein the at least four signal levels are non-uniformly distributed. The receiver side includes a corresponding equalizer which is implemented as a filter of the form f.sub.1y+f.sub.2y.sup.2+f.sub.0, where y is the incoming signal and the parameters f.sub.0, f.sub.1 and f.sub.2 are obtained using an adaptive filter.

A serial receiver combines continuous-time equalization, analog interleaving, and discrete-time gain for rapid, efficient data reception and quantization of a serial, continuous-time signal. A continuous-time equalizer equalizes a received signal. A number N of time-interleaved analog samplers sample the equalized continuous-time signal to provide N streams of analog samples transitioning at rate reduced by 1/N relative to the received signal. A set of N discrete-time variable-gain amplifiers amplify respective streams of analog samples. A quantizer then quantizes the amplified streams of analog samples to produce a digital signal.

A wireless communication device including a memory configured to store instructions; a processor coupled to the memory configured to execute the instructions stored on the memory, wherein the instructions are configured to receive a request message to update a radio access network (RAN) quantization scheme; determine an updated quantization scheme based on properties of a RAN; determine if the updated quantization scheme satisfies a RAN performance criterion; and generate a message including instructions for the updated quantization scheme.

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.

A transmitter for transmitting a data transmission signal in a reception area is provided with an input for receiving an information signal (IS) to be transmitted, a codingand/or modulation unit for coding and/or modulating the information signal with a certain codingand/or modulation scheme into the data transmission signal, and an output for supplying the data transmission signal, and an output for supplying the data transmission signal. In accordance with the invention, the codingand/or modulation unit is adapted to code and/or modulate the information signal with n different codingand/or modulation schemes (n2), and further is adapted to transmit an additional information signal by changing between these n codingand/or modulation schemes. The invention also relates to a receiver for receiving the data transmission signal transmitted by the transmitter.