A multi-user code division multiple access communication method, and corresponding transmitter and receiver include: the transmitter determines a complex-valued spreading sequence to be used by the transmitter, herein each element of the complex-valued spreading sequence is a complex number and values of real and imaginary parts of all elements in the complex-valued spreading sequence are from an M-element set of real numbers, and M is an integer larger than or equal to 2; the transmitter performs spreading processing on data symbols to be sent by using the complex-valued spreading sequence to generate a spread symbol sequence; and sends the spread symbol sequence. The receiver receives signals transmitted by multiple transmitters, and performs reception detection by using an interference cancellation signal detector, herein the complex-valued spreading sequences used by the multiple transmitters are used during detection.

An interface module has at least a configuration connection, a reset connection, a transmission connection and a reception connection. The interface module also has at least a first interface processing unit and a second interface processing unit which differs from the first interface processing unit and the connections of which can be connected to the connections of the interface module via a multiplexer. Only one set of interface connections needs to be provided on the interface module. The multiplexer is controlled by a level at the

A signal sending method, a signal receiving method, and a device are provided. A part that is of a first signal and that is carried on the k.sup.th subcarrier in the i.sup.th subcarrier group in N subcarrier groups is x.sub.i,n.sub.id(k), and a sequence {s.sub.i,n.sub.id(k)} related to x.sub.i,n.sub.id(k) is one of enumerated sequences. The enumerated sequences are sequences with relatively good cross-correlation. Therefore, for two subcarrier groups, provided that selected {s.sub.i,n.sub.id(k)} is two of the enumerated sequences, cross-correlation between signals carried in the two subcarrier groups can be ensured to be relatively good, thereby reducing interference between the signals and improving channel estimation performance.

A signal sending method, a signal receiving method, and a device are provided. A part that is of a first signal and that is carried on the k.sup.th subcarrier in the i.sup.th subcarrier group in N subcarrier groups is x.sub.i,n.sub.id(k), and a sequence {s.sub.i,n.sub.id(k)} related to x.sub.i,n.sub.id(k) is one of enumerated sequences. The enumerated sequences are sequences with relatively good cross-correlation. Therefore, for two subcarrier groups, provided that selected {s.sub.i,n.sub.id(k)} is two of the enumerated sequences, cross-correlation between signals carried in the two subcarrier groups can be ensured to be relatively good, thereby reducing interference between the signals and improving channel estimation performance.

A signal sending method, a signal receiving method, and a device for signal transmission or receiving are provided. A part that is of a first signal and that is carried on a k.sup.th subcarrier in an i.sup.th subcarrier group in N subcarrier groups is x.sub.i,n.sub.id(k), and a sequence {s.sub.i,n.sub.id(k)} related to x.sub.i,n.sub.id(k) is one of enumerated sequences. The enumerated sequences are sequences with relatively good cross-correlation. Therefore, for two subcarrier groups, provided that selected {s.sub.i,n.sub.id(k)} is two of the enumerated sequences, cross-correlation between signals carried in the two subcarrier groups can be ensured to be relatively good, thereby reducing interference between the signals and improving channel estimation performance.

A hybrid multi-layer method for decomposing of a source signal to a plurality of decomposed signals that can be used to collectively represent the source signal or recover the source signal. An example embodiment is a method that includes multi-layer (or multi-stage) signal decomposition to generate constant envelope signals without impact on the original signal. In an example embodiment, the method includes signal decomposition to maintain constant envelope properties and limit bandwidth expansion from the signal decomposition. The method includes decomposing a source signal into two first-stage decomposed signals that each have a constant envelope amplitude value. The method further includes iteratively decomposing each of the constant envelope signals into further-stage decomposed signals based on a threshold amplitude value at each iteration. The further-stage decomposed signals have a constant envelope with an envelope amplitude value in dependence of the threshold amplitude value at each iteration.

A hybrid multi-layer method for decomposing of a source signal to a plurality of decomposed signals that can be used to collectively represent the source signal or recover the source signal. An example embodiment is a method that includes multi-layer (or multi-stage) signal decomposition to generate constant envelope signals without impact on the original signal. In an example embodiment, the method includes signal decomposition to maintain constant envelope properties and limit bandwidth expansion from the signal decomposition. The method includes decomposing a source signal into two first-stage decomposed signals that each have a constant envelope amplitude value. The method further includes iteratively decomposing each of the constant envelope signals into further-stage decomposed signals based on a threshold amplitude value at each iteration. The further-stage decomposed signals have a constant envelope with an envelope amplitude value in dependence of the threshold amplitude value at each iteration.

A multi-user code division multiple access communication method, and corresponding transmitter and receiver include: the transmitter determines a complex-valued spreading sequence to be used by the transmitter, herein each element of the complex-valued spreading sequence is a complex number and values of real and imaginary parts of all elements in the complex-valued spreading sequence are from an M-element set of real numbers, and M is an integer larger than or equal to 2; the transmitter performs spreading processing on data symbols to be sent by using the complex-valued spreading sequence to generate a spread symbol sequence; and sends the spread symbol sequence. The receiver receives signals transmitted by multiple transmitters, and performs reception detection by using an interference cancellation signal detector, herein the complex-valued spreading sequences used by the multiple transmitters are used during detection.

A data transmission method includes the following steps: determining a transmission resource to be used and a complex-valued spreading sequence to be used; processing a data symbol to be sent by using the complex-valued spreading sequence to generate a symbol sequence; and sending the symbol sequence through the transmission resource.

A data transmission method includes the following steps: determining a transmission resource to be used and a complex-valued spreading sequence to be used; processing a data symbol to be sent by using the complex-valued spreading sequence to generate a symbol sequence; and sending the symbol sequence through the transmission resource.