The present invention provides an apparatus of transmitting broadcast signals, the apparatus including, an encoder for encoding service data, a frame builder for building at least one signal frame by mapping the encoded service data, a modulator for modulating data in the built at least one signal frame by an Orthogonal Frequency Division Multiplexing, OFDM, scheme and a transmitter for transmitting the broadcast signals having the modulated data.

An apparatus for processing a received radio signal includes at least one processor and at least one memory. The at least one memory storing computer program code. The at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to at least in part perform processing (received radio signal data with first and second signal processing chains, which respectively include first and second processing modules configured to respectively determine first output and an estimation of the first output data, and determine second output data using a neural network based on the estimation; updating parameters of the neural network based on the first output data and the second output data; and after the updating, processing the received radio signal data with the second signal processing chain, without applying the first processing module.

An OFDM transmitter and an OFDM receiver respectively transmit and receive N (N≥2, N is an integer) control symbols. For each control symbol, a guard interval time-domain signal is, for example, identical to a signal obtained by frequency-shifting at least a portion of a useful symbol time-domain signal by an amount different from any other symbol, or to a signal obtained by frequency-shifting one or both of a portion and a span of a useful symbol interval time-domain signal different from any other symbol by a predetermined amount.

An FEC coder in a transmission device according to an exemplary embodiment of the present disclosure performs BCH coding and LDPC coding based on whether a code length of the LDPC coding is a 16k mode or a 64k mode. A mapper performs mapping in an I-Q coordinate to perform conversion into an FEC block, and outputs pieces of mapping data (cells). The mapper defines different non-uniform mapping patterns with respect to different code lengths even an identical coding rate is used by the FEC coder. This configuration improves a shaping gain for different error correction code lengths in a transmission technology in which modulation of the non-uniform mapping pattern is used.

A data processing apparatus is arranged to map input data symbols to be communicated onto a predetermined number of sub-carrier signals of Orthogonal Frequency Division Multiplexed OFDM symbols. The predetermined number of sub-carrier signals is determined in accordance with one of a plurality of operating modes and the input data symbols are divided into first sets of input data symbols and second sets of input data symbols.

A method for transmitting machine type communication (MTC) downlink data. The method includes acquiring, by a user equipment (UE), downlink transmission parameters, where the downlink transmission parameters include a quantity of resource blocks in downlink transmission bandwidth that is configured by a base station for the UE, an antenna port used by the base station for sending the MTC downlink data, and at least one of the following a cell-specific frequency shift value or a cyclic prefix (CP) type, setting, by the UE, a local oscillator frequency of a receiver according to the downlink transmission parameters; and receiving, by the UE, the MTC downlink data sent by the base station, where a subcarrier located in a subcarrier reservation location does not carry any data signal or reference signal, and the subcarrier reservation location is determined in the downlink transmission bandwidth by the base station according to the downlink transmission parameters.

A method performed by an electronic device is described. The method includes receiving a long training field (LTF) in a preamble of a packet. A power of the LTF is boosted relative to a power of a data field of the packet. The method also includes receiving a power amplifier (PA) model or a PA distortion error from a transmitting device. The method further includes regenerating a post-PA transmitted LTF based on the PA model or the PA distortion error. The method additionally includes demodulating the data field based on an estimated channel with deboosting.

A device, such as a base station or user equipment (UE), may identify a narrowband reference signal (NB-RS) energy per resource element (EPRE) for a NB-RS to be transmitted in a wireless transmission. The device may identify a ratio of a narrowband physical downlink shared channel (N-PDSCH) EPRE to the NB-RS EPRE for orthogonal frequency division multiplexing (OFDM) symbols containing neither a cell-specific reference signal (CRS) nor a NB-RS. In deployments where NB transmissions are transmitted in a guard-band adjacent to a wideband system bandwidth, a device may identify a second ratio for N-PDSCH EPRE to CRS EPRE within OFDM symbols containing CRS. In deployments where NB transmissions are transmitted in-band with the wideband system bandwidth, a device may identify a third ratio of NB-RS EPRE to CRS EPRE, and a fourth ratio of N-PDSCH EPRE to NB-RS EPRE within OFDM symbols containing NB-RS transmissions.

A technique for de-mapping a point in a constellation diagram into a bit sequence is presented. The de-mapping provides for each bit of the bit sequence an output value with a sign of the output value indicating a bit value and a magnitude of the output value indicating probability information in the form of a distance to a decision boundary in the constellation diagram. A method aspect of the technique presented herein comprises receiving a signal indicative of a constellation point, wherein the constellation point represents a bit sequence having a most significant bit and at least one next significant bit, deriving a first output value for the most significant bit based on a first decision boundary, receiving a priori information, and deriving a second output value for the next significant bit based on the first output value, the a priori information and a second decision boundary.

A method and an apparatus for transmitting broadcast signals thereof are disclosed. The method for transmitting broadcast signals includes processing input streams into BB frames in PLPs; encoding data of the PLPs; building at least one signal frame by mapping the encoded data of the PLPs; and modulating data in the built signal frame by OFDM method and transmitting the broadcast signals having the modulated data, wherein at least one of the BB frames includes a stuffing field and a first indicator describing whether the stuffing field is included in the BB frame.