Techniques are described that provide nested constellations in which a lower order modulation scheme may be nested within constellation points of a higher-order modulation scheme. A higher-order modulation scheme, having a first constellation, may be used for a first subset of transmissions (e.g., data payload transmissions). A lower-order modulation scheme, having a second constellation, may be used for a second subset of transmissions (e.g., reference signal transmissions, embedded control transmissions, tapered payload transmissions, etc.). A subset of constellation points of the first constellation may be selected for transmitting the second subset of transmissions. A receiver may receive the transmissions and demodulate/decode the transmissions. In the event that other transmitters are transmitting concurrently, and using similar nested constellation techniques, the receiver may be able to perform improved interference mitigation compared to interference mitigation that may be performed on interfering signals that use different constellation points.

A radio analysis apparatus includes: a processor that calculates a modulation index of a radio signal generated by performing frequency shift keying on a baseband signal, based on phase shift amounts of the radio signal; and a memory that holds information in which bit patterns of the baseband signal are associated with correction values for correcting the phase shift amounts that have dropped by band limitation on the baseband signal. The processor restores the bit patterns of the baseband signal based on the phase shift amounts of the radio signal, corrects the phase shift amounts of the radio signal by using the correction values corresponding to the restored bit patterns, and calculates the modulation index based on the corrected phase shift amounts.

A communication apparatus, a communication system, a communication method, and a non-transitory computer readable medium capable of reducing differences among receiving characteristics of a plurality of quadrature amplitude-modulated signals and optimizing the capacity of transmission signals are provided. A communication apparatus (1) according to the present disclosure includes a transmitting unit (2) capable of transmitting a plurality of types of quadrature amplitude-modulated signals, and an addition unit (3) that adds error correction codes to the quadrature amplitude-modulated signals. Further, the communication apparatus (1) includes a control unit (4) that changes the number of bits of the error correction code according to the type of the quadrature amplitude-modulated signal.

Provided are a data modulation method and device, a data demodulation method and device, a service node, a terminal, and a medium. The data modulation method is applied to the service node, and the data modulation method includes that: a modulation parameter A is determined according to a modulation manner of data; and the data is modulated according to a target constellation point symbol, where the target constellation point symbol is a product of A and X, and X is an initial constellation point symbol corresponding to the modulation manner.