A method of modulating complex symbols is provided, which delivers a multiple carrier signal. The method performs the following acts for at least one base block of N×K complex symbols, where N and K are integers such that N>1 and K≧1: extending the base block to deliver a block of N×(2K−1) elements, referred to as an “extended” block; phase shifting the extended block, delivering a phase shifted extended block; filtering the phase shifted extended block, delivering a block of N×(2K−1) filtered elements, referred to as a “filtered” block; mapping the N×(2K−1) filtered elements of said filtered block onto MK frequency samples, where M is the total number of carriers and M≧N; and transforming the MK frequency samples from the frequency domain to the time domain.

In one exemplary embodiment, a wireless communication apparatus transmitting data by using several sub-carriers. The wireless communication apparatus comprises a signal modulator, a signal processor, a storage, a computing processor, and a transmitter. The signal modulator generates a modulated signal in time domain based on the data. The signal processor perfoiliis signal processing on the modulated signal, and comprises a window module and a filter module. The window module performs windowing operation on the modulated signal to generate a window-operated signal. The filter module performs filtering operation on the window-operated signal to generate a transmitting signal in time domain. The computing processor perfoiiiis operations of setting up the window module and the filter module according to a window characteristic function and a filter characteristic function. The transmitter transmits the transmitting signal.

Conventional filter bank multi-carrier (FBMC) wireless communication systems offer superior spectral properties compared to the cyclic-prefix orthogonal frequency-division multiplexing (CP-OFDM) approach, at the cost of an inherent shortcoming in dispersive channels called intrinsic imaginary interference. In this disclosure the DP-FBMC system was disclosed. A DP-FBMC based communication system uses two orthogonal polarizations for wireless communication systems: dual-polarization FBMC (DP-FBMC). The system significantly suppresses FBMC intrinsic interference. For the disclosed DP-FBMC all the multicarrier techniques used in CP-OFDM systems for channel equalization etc., are applicable without using complex processing methods that are required for conventional FBMC. Disclosed DP-FBMC also is more robust in multipath fading channels, and also to receiver carrier frequency offset (CFO) and Timing offset (TO). In the disclosed DP-FBMC system, three different structures may be used based on different multiplexing techniques.

A method of designing a digital filter for example for use in an FBMC/OQAM telecommunications system, with a target overlapping factor and meeting a specified signal to interference ratio is described, whereby a candidate filter design defined by an impulse response, satisfying the Nyquist criterion and having an overlapping factor higher than the target is selected, and the time and frequency coefficients of its impulse response inverted to define a new filter design; and

truncating the impulse response defining said new filter design to the minimum number of coefficients achieving said specified signal to interference ratio.

A broadcast TV signal is a DVB-T2 based system. A DVB-T2 transmitter checks OFDM symbols before transmission to determine a level of adjacent channel interference (ACI). If the of level of ACI is too high, i.e., above a threshold value, the OFDM symbols are filtered before transmission. Otherwise, the OFDM symbols are transmitted without filtering. A filtering field is added to an LI pre-signaling table of the broadcast DVB-T2 signal to signal a DVB-T2 receiver when the received OFDM symbols have been filtered.

Methods, apparatus, systems and articles of manufacture to implement a signal scrambler are disclosed. An example method includes generating, by executing an instruction with a processor, a controlled random sequence based on a plurality of subcarriers and a random pulse sequence. The example method also includes forming, by executing an instruction with the processor, an output sequence by combining a source sequence with the controlled random sequence, the controlled random sequence to modify a characteristic of the source sequence in a frequency domain.

Various communication systems may benefit from improved radio signaling. For example, communication systems may benefit from selective or partial filtering of a radio signal. A method, in certain embodiments, may include analyze at a network entity a radio signal comprising a plurality of orthogonal frequency division multiplexing symbols. The radio signal comprises at least one point of discontinuity between the plurality of symbols. The method may also include filtering a select time domain sample of the radio signal in the plurality of symbols. The select sample surrounds the at least one point of discontinuity. In addition, the method may include replacing the select time domain sample surrounding the at least one point of discontinuity of the radio signal with the filtered sample in the plurality of symbols.

Embodiments of the present disclosure relate to systems and methods to generate a signal in a communication network. The method comprises filtering a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) data signal, and one of a DFT-S-OFDM and orthogonal frequency division multiplexing (OFDM) reference signal (RS) using a data filter and a RS filter respectively, to produce filtered data signal and filtered RS. The RS filter has one to one relationship with the data filter. Thereafter, port mapping the filtered RS to a corresponding port assigned to the transmitter to obtain port mapped filtered RS, wherein the port mapped filtered RS comprises a first subset of non-zero locations comprising of the filtered RS values and a second subset of zero locations comprising of zero values.

Methods and systems for signal transmission in millimeter wave (mmW) range. A set of sequences is used to encode a data signal for one layer in a group of layers. Each sequence in the set of sequences has a length equal to the number of resources shared among the group of layers. At least a portion of the sequences have a low density of non-zero values, and the non-zero values are assigned to a subset of the shared resources. Each sequence assigns a non-zero value to at most one resource of the subset of shared resources, and all non-zero values assigned by all sequences have equal power amplitudes.

Methods, apparatus, and systems for reducing Peak Average Power Ratio (PAPR) in signal transmissions are described. In one example aspect, a wireless communication method includes determining, for a time-domain sequence x(i), an output sequence s(k). The output sequence s(k) is an inverse Fourier transform of a frequency-domain sequence S(j). S(j) is an output of a frequency-domain shaping operation based on a frequency-domain sequence Y(j) and a set of coefficients. Y(j) corresponds to the time-domain sequence x(i) based on a parameter N. The number of non-zero coefficients in the set of coefficients is based on N, and values of the non-zero coefficients correspond to phase values distributed between 0 to π/2 to reduce a peak to average power ratio of the output sequence. The method also includes generating a waveform using the output sequence s(k).