Channel estimation with reduced overhead in a filter bank multi-carrier (FBMC) system is enabled by use of frequency-time blocks each comprising a pilot field with two pilot symbols and data symbols outside the pilot field. In embodiments, nearest neighbors of the pilot field are populated with data symbols which fulfill one or more symmetry relations enabling approximate interference cancellation. In a first embodiment, the pilot field consists of two frequency-consecutive and time-coinciding positions; the pilot field may be time-initial in a transmission or may be located in the interior of the transmission. In a second embodiment, a block comprises two frequency-coinciding and time-consecutive pilot symbols; the pilot field may be frequency-initial in a transmission or may be located in the interior of the transmission.

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.

A method and apparatus for orthogonal frequency division multiplexing (OFDM) modulation includes separating a frequency-domain sequence of complex numbers into a first portion and a second portion that is disjoint with the first portion, each of the first portion and the second portion including a respective half of the complex numbers of the frequency-domain sequence, and generating a time-domain sequence having a real in-phase component that is a function of the first portion only, and an imaginary quadrature-phase component that is a function of the second portion only.

A filter bank multi-carrier (FBMC)-offset quadrature amplitude modulation (OQAM) system is disclosed. The FBMC-OQAM system includes a processing circuitry which is configured to receive a signal over a transmission medium, equalize the signal by a convolution neural network (CNN) equalizer, wherein the CNN equalizer is configured to estimate the received signal without performing channel estimation, and output the estimated signal as a bit stream.

A terminal apparatus for communicating with a base station apparatus includes a transmission unit configured to transmit Phase-tracking reference signals (PTRS), and an higher layer processing unit configured to configure information for indicating a time density and/or a frequency density of the PTRS. A PTRS pattern is configured such that the time density of the PTRS is higher for a larger Modulation and Coding Scheme (MCS) scheduled for the terminal apparatus, and the frequency density of the PTRS is based on the number of resource blocks scheduled for the terminal apparatus.

Aspects of the present application provide methods and devices for time domain implementation of a single carrier waveform such as single carrier quadrature amplitude modulation (QAM) DFT-s-OFDM and single carrier Offset QAM (OQAM). A time domain implementation allows flexible symbol lengths, lower implementation complexity as a large IDFT operation is not required in the time domain and support for variable cyclic prefix (CP) length. An OQAM implementation utilizes a pre-processing step to convert a K complex QAM symbol sequence into a 2K OQAM symbol sequence and generates a sequence for transmission in the time domain as opposed to the frequency domain.

A signal processing circuit includes an encoding circuit and a subcarrier sorting circuit. The encoding circuit is arranged to encode an input data to generate multiple codewords corresponding to a symbol. The subcarrier sorting circuit is arranged to sequentially arrange multiple subcarriers into an array, wherein a size of the array is M*N, N is a number of columns, N is equal to a number of the multiple codewords corresponding to the symbol, M is a number of rows, and M is a number of the multiple subcarriers divided by N; and the multiple subcarriers are sequentially arranged into the array starting from a row of the array, and subcarriers comprised in each column of the array are arranged to transmit one of the multiple codewords.

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.

A communication device generates a transmission signal for transmission via a wireless communication channel, wherein the transmission signal corresponds to a physical layer (PHY) data unit that conforms to a range extension mode of a first communication protocol. Generating the PHY data unit includes generating a preamble of a PHY data unit, wherein the preamble is generated to include: a legacy signal field that includes information indicating a duration of the PHY data unit, a duplicate of the legacy signal field, a plurality of subfields of a non-legacy signal field, and a plurality of additional subfields with the same data as the plurality of subfields of the non-legacy signal field. The plurality of subfields of the non-legacy signal field and the plurality of additional subfields are modulated to signal to a receiving device that the PHY data unit conforms to the range extension mode of a first communication protocol.

Aspects of the present application provide methods and devices for time domain implementation of a single carrier waveform such as single carrier quadrature amplitude modulation (QAM) DFT-s-OFDM and single carrier Offset QAM (OQAM). A time domain implementation allows flexible symbol lengths, lower implementation complexity as a large IDFT operation is not required in the time domain and support for variable cyclic prefix (CP) length. An OQAM implementation utilizes a pre-processing step to convert a K complex QAM symbol sequence into a 2K OQAM symbol sequence and generates a sequence for transmission in the time domain as opposed to the frequency domain.