A base station transmits a layered data signal to multiple devices that are in close proximity to each other where the layered data signal includes at least first data on a first data layer directed to a first device and second data on a second data layer directed to a second device. The base station also transmits a single control message to both devices where the control message comprises location dependent control information directed to both devices. The control message also comprises data layer control information arranged in multiple fields where data layer control information in a field is associated with a device and allows the associated device to recover the data from a data layer assigned to the device.

An apparatus and method for generating a broadcast signal frame corresponding to a time interleaver supporting a plurality of operation modes are disclosed. An apparatus for generating broadcast signal frame according to an embodiment of the present invention includes a combiner configured to generate a multiplexed signal by combining a core layer signal and an enhanced layer signal at different power levels; a power normalizer configured to reduce the power of the multiplexed signal to a power level corresponding to the core layer signal; a time interleaver configured to generate a time-interleaved signal by performing interleaving that is applied to both the core layer signal and the enhanced layer signal; and a frame builder configured to generate a broadcast signal frame including a preamble for signaling time interleaver information corresponding to the time interleaver, the time interleaver uses one of time interleaver groups, and the time interleaver performs the interleaving by using one of a plurality of operation modes.

A method in a transmitter comprises transmitting a first data block to a first user, using an index modulation scheme and using SSD for transmitting the first data block. In some embodiments, the index modulation scheme is index-modulated OFDM and the indices comprise subcarrier indices. The method further comprises determining that a retransmission of the first data block to the first user is needed, and rearranging a bit mapping of bits in the first data block to indices used in the index modulation scheme, compared to a bit mapping previously used for transmitting the first data block to the first user using the index modulation scheme. The method further comprises retransmitting the second data block to the first user, where this retransmitting comprises using the index modulation scheme with the rearranged bit mapping and using SSD.

An apparatus for transmitting broadcasting signal using transmitter identification and method using the same are disclosed. An apparatus for transmitting broadcasting signal according to an embodiment of the present invention includes a waveform generator configured to generate a host broadcasting signal; a transmitter identification signal generator configured to generate a transmitter identification signal for identifying a transmitter; and a combiner configured to inject the transmitter identification signal into the host broadcasting signal in a time domain so that the transmitter identification signal is transmitted synchronously with the host broadcasting signal.

Provided is a signal modulation apparatus configured to modulate an input signal into a multidimensional QAM signal using multidimensional QAM, in which Multidimensional QAM is QAM in which two-dimensional QAM is configured in a multidimensional manner using a plurality of consecutive time slots, a constellation for multidimensional QAM is part of a combination of a constellation of first two-dimensional QAM, and a constellation of second two-dimensional QAM.

A digital radio OFDM modulator and demodulator provide an efficient mode and a backwards-compatible mode to work with IEEE 802.15.4g or a similar standard. In backwards-compatible mode, they use a single method for error encoding physical header and payload transmit data, and a single method for detecting and correcting errors in physical header and payload receive data. In efficient mode, they use two different methods. The payload is BCH-LDPC encoded. They may also use mapping constellations that are not available in IEEE 802.15.4g, including 64-QAM, 256-QAM, and APSK. To ensure that physical header data can be received more robustly than payload data, they use frequency diversity of the physical header data, and selection maximal ratio combining (SMRC) in the demodulator to reduce the bit error rate (BER) at a low cost.

An apparatus for generating broadcast signal frame according to an embodiment of the present invention includes a combiner configured to generate a multiplexed signal by combining a core layer signal and an enhanced layer signal at different power levels; a power normalizer configured to reduce the power of the multiplexed signal to a power level corresponding to the core layer signal; a time interleaver configured to generate a time -interleaved signal by performing interleaving that is applied to both the core layer signal and the enhanced layer signal; and a frame builder configured to generate a broadcast signal frame including a preamble for signaling time interleaver information corresponding to the time interleaver, the time interleaver uses one of time interleaver groups, and a boundary between the time interleaver groups is a boundary between Physical Layer Pipes (PLPs) of a core layer corresponding to the core layer signal.

An apparatus and method for generating a broadcast signal frame for signaling a time interleaving mode are disclosed. An apparatus for generating broadcast signal frame according to an embodiment of the present invention includes a time interleaver configured to generate a time-interleaved signal by performing time interleaving on a BICM output signal; and a frame builder configured to generate a broadcast signal frame including a preamble for signaling a time interleaving mode corresponding to the time interleaver for each of physical layer pipes (PLPs).

Aspects of the disclosure include an apparatus at base station side in a wireless communication system for multi-user superposition transmission. The apparatus includes a superposition control unit and an indication generation unit. The superposition control unit is configured to insert, into a data stream of each user equipment in a group of user equipment comprising a plurality of user equipment, a demodulation reference signal corresponding to the data stream, and superpose demodulation reference signals corresponding to data streams of respective user equipment. The indication generation unit is configured to generate, for at least a first user equipment among the plurality of user equipment, an indication regarding a demodulation reference signal corresponding to a data stream of other user equipment among the plurality of user equipment, to assist the first user equipment in demodulating data transmitted in the multi-user superposition transmission.

A technique for performing a multi-layer transmission of data on a radio frequency is described. The multi-layer transmission comprising multiple layers each having a different robustness on the radio frequency. As to a method aspect of the technique, a contention procedure is performed with respect to each of a plurality of access classes, ACs, for accessing the radio frequency. The multi-layer transmission is performed upon success of the contention procedure of at least one of the ACs. In a transmission opportunity defined by the successful contention procedure, data associated with the successful AC is transmitted on a main layer of the multi-layer transmission simultaneously with data associated with at least one further AC on at least one further layer, which is less robust than the main layer of the multi-layer transmission.