Transmitting apparatus and receiving apparatus for communication systems use coded orthogonal frequency-division multiplexed (COFDM) dual-subcarrier-modulation (DCM) signals. The same coded data is mapped both to COFDM subcarriers located in the lower-frequency half spectrum of the DCM signal and to COFDM subcarriers located in its upper-frequency half spectrum. Symbol constellation mappings of COFDM subcarriers in those half spectra preferably employ labeling diversity providing peak-to-average power ratio (PAPR) of the COFDM DCM signals substantially reduced from PAPR of double-sideband COFDM signals.

Systems and methods for processing a Random Access (RA) transmission are disclosed. In some embodiments, a method of operating a radio access node in a cellular communications network includes receiving an RA transmission from a wireless device. The method also includes detecting an RA preamble in the RA transmission from the wireless device and estimating a timing parameter of the wireless device using the RA transmission from the wireless device separately from detecting the RA preamble. By estimating the timing parameter separately from detecting the RA preamble, increased detection of the RA preamble is possible while also increasing the precision of the timing parameter estimate. In some embodiments, this separation also enables a complexity reduction of the receiver if a low complexity detector is used first and then the high complexity timing estimator is only used when an RA preamble is detected.

This application relates to a sequence detection method and a device. One example method includes receiving a first sequence carried on a plurality of subcarriers; differentiating the first sequence based on L granularities, to obtain a first differential sequence set comprising L sequences; determining K candidate frequency domain root sequences in the U candidate frequency domain root sequences based on differential sequence cross correlation value sets corresponding to the U candidate frequency domain root sequences; and determining a candidate frequency domain root sequence and a time domain cyclic shift value that correspond to the first sequence, based on the first sequence and the K candidate frequency domain root sequences.

A system, method and device to overcome the effects of mobility in OFDM wireless cellular networks. Individual beams are isolated and Doppler impairments are compensated so the constituent beams can reach the users in DL with ideally no Doppler impairments. Similarly in UL the signals corresponding to the different spatial beams are detected and their Doppler impairments compensated.

A method for estimating a frequency offset of a reception signal and, more particularly, a signal processing method which can be applied to a receiver modem in a wireless communication system, are provided. The method includes using an absolute value within a specific time area in an inverse discrete fourier transform (IDFT) output of a decorrelation signal between a reception signal and a reference signal, and enabling a highly approximate estimation of a frequency offset through only a single decorrelation test using a characteristic of a predetermined permutation of a signal.

The present disclosure describes the generation of long sequences from short sequences to support concurrent transmissions of large numbers of machine-type communication devices operating in a wireless communication system. These long sequences may be assigned to devices so that the devices can use the long sequences scramble their transmissions. The use of such long sequences permits many machine-type communication devices to transmit during the same time and frequency resource.

A method and apparatus having a synchronization signal sequence structure for low complexity cell detection is provided. The method includes establishing a set of a plurality of synchronization signal sequences to be used in connection with a communication target. Each one of the plurality of synchronization signal sequences includes at least a first sub-sequence, which includes either a first preselected sequence or a complex conjugate of the first preselected sequence, and a second sub-sequence, which includes either a second preselected sequence or a complex conjugate of the second preselected sequence. The second preselected sequence is different than the first preselected sequence, and is different than the complex conjugate of the first preselected sequence. Further, a length of the first sub-sequence and a length of the second sub-sequence are smaller than a length of the synchronization signal sequence. A signal including a synchronization signal is then received, where the synchronization signal comprises one of the synchronization signal sequences from the set of the plurality of synchronization signal sequences, and the synchronization signal is then detected.

A system, method and device to overcome the effects of mobility in OFDM wireless cellular networks. Individual beams are isolated and Doppler impairments are compensated so the constituent beams can reach the users in DL with ideally no Doppler impairments. Similarly in UL the signals corresponding to the different spatial beams are detected and their Doppler impairments compensated.

A method is provided for receiving an OQAM multi-carrier signal, which implements a step of estimating, in the time domain, at least one time, phase, and/or frequency shift of the multi-carrier signal. The estimation step implements at least one estimator in order to estimate the time shift, referred to as a time estimator, and/or at least one estimator for estimating the phase shift, referred to as a phase estimator, and/or at least one estimator for estimating the frequency shift, referred to as a frequency estimator. The multi-carrier signal includes at least one preamble, and at least one of the estimators takes into account coefficients of a prototype filter used in transmission in order to shape at least one preamble inserted into the multi-carrier signal.

The present invention provides a method for detecting an uplink synchronization signal in a wireless access system supporting a high frequency band, a method for designing a detection filter for the same, and devices for supporting the methods. A method by which a base station detects a random access channel (RACH) signal in a wireless access system supporting a high frequency band, according to one embodiment of the present invention, comprises the steps of: allocating a cyclic shift value used in the base station; configuring a reception signal vector for signals transmitted through the RACH; deriving a cyclic shift candidate greater than or equal to a reference value from the reception signal vector by using a first detection filter; and detecting the RACH signal from the cyclic shift candidate by using a second detection filter, wherein the first detection filter and the second detection filter can be set on the basis of the cyclic shift value.