Communicating using spread spectrum. A legacy RF signal is intercepted from a legacy radio. spread spectrum processing is performed on the legacy RF signal to create a spread signal. The spread signal is transmitted to a receiver, whereafter the spread signal is de-spread to recover the legacy RF signal.

A network device for generating an expanded long training sequence with a minimal peak-to-average ratio. The network device includes a signal generating circuit for generating the expanded long training sequence. The network device also includes an Inverse Fourier Transform for processing the expanded long training sequence from the signal generating circuit and producing an optimal expanded long training sequence with a minimal peak-to-average ratio. The expanded long training sequence and the optimal expanded long training sequence are stored on more than 52 sub-carriers.

A peak suppression device includes an acquiring unit that acquires multiple envelopes of carrier signals that are included in a multicarrier signal, an adding unit that adds the envelopes to generate a combined envelope, a detecting unit that detects a peak value and a peak timing of the multicarrier signal by using the combined envelope, and a suppressing unit that suppresses a peak of the multicarrier signal in accordance with the peak value and the peak timing.

Embodiments of the present disclosure relate to a method and system to generate a waveform in a communication network. The transmitter receives an input data and transmit a generated waveform to another communication system. The input data is spread with a spread code to generate a spread data and rotated using a constellation rotation operation to produce a rotated data. The rotated data is then precoded using precoding filter to produce a precoded data, and transformed into DFT output data using DFT operation. The DFT output data is then mapped with subcarriers to generate the sub-carrier mapped DFT data and modulated using Orthogonal Frequency Division Multiplexing (OFDM) modulation to generate the waveform with low PAPR.

Selective processing of one or more packets to be transmitted from a wireless communication device to another wireless communication device is effective to reduce the peak to average power ratio (PAPR) of the transmission. The one or more packets are transmitted via two or more sub-bands of an available transmission medium. The number of coefficients or factors within that sequence corresponds to the number of sub-bands via which the one or more packets are to be transmitted. Also, a phase ramp or time-domain cyclic shift may be added to one or more of the packets after having undergone multiplication by one of the coefficients or factors within the sequence.

Embodiments of the present disclosure provide an estimation apparatus and compensation apparatus for clipping distortion of multicarrier signals and a receiver. The estimation apparatus includes: a first calculating unit configured to multiply an error signal of each subcarrier in all or part of subcarriers in received multicarrier signals by a conjugation of an error signal of a subcarrier neighboring or spaced apart from each subcarrier; a second calculating unit configured to calculate an average value of all results of multiplication; a third calculating unit configured to calculate parameters of the clipping distortion of the multicarrier signals according to the average value; and an estimating unit configured to estimate the clipping distortion of the multicarrier signals according to the calculated parameters of the clipping distortion. By calculating the parameters of the clipping distortion of the multicarrier signals according to the error signals of the subcarriers, the clipping distortion of the multicarrier signals may be accurately estimated and compensated, with the method of calculation being simple and the bit error rate being low.

A method of uplink transmission to reduce peak-to-average power ratio (PAPR) in enhanced licensed assisted access (eLAA) is proposed. New design of Physical Uplink Control Channel (PUCCH) and Physical Uplink Shared Channel (PUSCH) is proposed. Across frequency domain of the channel bandwidth, multiple resource interlaces are allocated for different UEs for uplink PUCCH/PUSCH transmission to satisfy the occupied channel bandwidth requirement for unlicensed carrier access. In addition, uplink transmission with co-phasing terms are applied to reduce PAPR of the resulted waveform.

Embodiments of the present disclosure relate to a method and system to generate a waveform in a communication network. The transmitter receives an input data and transmit a generated waveform to another communication system. The input data is spread with a spread code to generate a spread data and rotated using a constellation rotation operation to produce a rotated data. The rotated data is then precoded using precoding filter to produce a precoded data, and transformed into DFT output data using DFT operation. The DFT output data is then mapped with subcarriers to generate the sub-carrier mapped DFT data and modulated using Orthogonal Frequency Division Multiplexing (OFDM) modulation to generate the waveform with low PAPR.

Techniques for peak-to-average power ratio (PAPR) reduction are described. Wireless devices may use one or more PAPR shaping resources, such as expanded bandwidth and/or pulse-shaping filtering, for shaping a signal to reduce PAPR. For example, expanded bandwidth may be utilized for adding a cyclic affix (CA), such as may comprise a cyclic prefix (CP), cyclic suffix (CS), etc., and combinations thereof, to a frequency domain data signal to provide a CP augmented frequency domain data signal used to generate a reduced PAPR time domain data signal. Additionally or alternatively, pulse-shaping filtering may be applied to a frequency domain signal to provide a pulse-shaped frequency domain data signal used to generate a reduced PAPR time domain data signal. Other aspects and features are also claimed and described.

A transmitter includes: a frame generator configured to generate a frame including a frame starting symbol, at least one data symbol and a frame closing symbol; a pilot and reserved tone inserter configured to insert pilots and reserved tones in at least one of the frame starting symbol, the data symbol and the frame closing symbol such that positions of the reserved tones do not overlap positions of the pilots in the at least one of the frame starting symbol, the data symbol and the frame closing symbol; and a transmitter configured to transmit the frame in which the pilots and the reserved tones are inserted, wherein the reserved tones are not used to transmit data in the frame.