In one aspect, a method for estimating residual carrier frequency offset (CFO) in a phase-modulated wireless signal having pseudo noise (PN) spreading is provided. The method includes receiving, at a digital transceiver, a plurality of PN spread blocks of in-phase and quadrature (I/Q) samples of the phase-modulated wireless signal and performing sample-level de-rotation, symbol-level de-spreading, and sign alignment. The method also includes estimating a phase difference and determining an estimated residual CFO based on the phase difference.

An envelope signal time delay adjustment apparatus includes a negative group delay unit for converting an envelope signal input from a signal generator into an envelope signal having a group delay of a negative value whose frequency increases from a predetermined frequency band; an envelope-tracking modulator for power-amplifying and outputting the envelope signal output from the negative group delay unit; and a frequency limiting unit for limiting a bandwidth of the envelope-tracking modulator to be lower than an original bandwidth of the envelope-tracking modulator.

A method of wireless communication by a user equipment includes determining an allocation of a set of tones in a symbol for conveying data. The method further includes determining to use m-ary phase shift keying (MPSK) to modulate the data onto a subset of tones of the set of tones. The method further includes modulating the data onto the subset of tones based on a mapping, wherein the mapping maps pairs of data values with a largest Hamming distance from each other to pairs of constellation points with a maximum Euclidean distance from each other.

Methods, systems, and devices for wireless communications are described. A non-coherent modulation configuration may be selected for a transmission of a set of data based on a radio frequency spectrum band used for the transmission. After selecting the non-coherent modulation configuration, the set of data may be modulated using a differential phase shift keying modulation technique. After selecting the non-coherent modulation configuration, a set of frequency-domain symbols may be generated from the set of modulated symbols using a discrete Fourier transform. The set of frequency-domain symbols may be mapped to a set of subcarriers, and a time-domain waveform may be generated from the mapped set of frequency-domain symbols, yielding a time-domain waveform. The time-domain waveform may be transmitted over the radio frequency band.

A method of compensating for IQ mismatch (IQMM) in a transceiver may include sending first and second signals from a transmit path through a loopback path, using a phase shifter to introduce a phase shift in at least one of the first and second signals, to obtain first and second signals received by a receive path, using the first and second signals received by the receive path to obtain joint estimates of transmit and receive IQMM, at least in part, by estimating the phase shift, and compensating for IQMM using the estimates of IQMM. Using the first and second signals received by the receive path to obtain estimates of the IQMM may include processing the first and second signals received by the receive path as a function of one or more frequency-dependent IQMM parameters.

The present disclosure discloses a method and a system for providing a code cover to Orthogonal Frequency Division Multiplexing (OFDM) symbols in a multiple user system. A data sequence is received from each of a plurality of users. Further, a reference sequence is generated for the data sequence of each of the plurality of users. Each of the reference sequence is multiplied with a code cover which are orthogonal to each other. Each of the reference sequence is time-multiplexed with corresponding data sequence, to generate a corresponding multiplexed sequence. Further, a Discrete Fourier Transform (DFT) is performed on each of the multiplexed sequence to generate a corresponding DFT-spread-Orthogonal Frequency Division Multiplexing (DFT-s-OFDM) symbol. Lastly, the corresponding DFT-s-OFDM symbol is processed for transmitting over corresponding one or more channels.

Systems and methods for measuring wireless uplink signal quality of a P25 H-CPM uplink waveform are provided. In particular, such systems and methods can include calculating an SINR measurement and/or an FBER measurement for the P25 H-CPM uplink waveform to determine whether P25 user equipment has been successfully deployed.

A method of compensating for IQ mismatch (IQMM) in a transceiver may include sending first and second signals from a transmit path through a loopback path, using a phase shifter to introduce a phase shift in at least one of the first and second signals, to obtain first and second signals received by a receive path, using the first and second signals received by the receive path to obtain joint estimates of transmit and receive IQMM, at least in part, by estimating the phase shift, and compensating for IQMM using the estimates of IQMM. Using the first and second signals received by the receive path to obtain estimates of the IQMM may include processing the first and second signals received by the receive path as a function of one or more frequency-dependent IQMM parameters.

The present disclosure discloses a method and a system for providing a code cover to Orthogonal Frequency Division Multiplexing (OFDM) symbols in a multiple user system. A data sequence is received from each of a plurality of users. Further, a reference sequence is generated for the data sequence of each of the plurality of users. Each of the reference sequence is multiplied with a code cover which are orthogonal to each other. Each of the reference sequence is time-multiplexed with corresponding data sequence, to generate a corresponding multiplexed sequence. Further, a Discrete Fourier Transform (DFT) is performed on each of the multiplexed sequence to generate a corresponding DFT-spread-Orthogonal Frequency Division Multiplexing (DFT-s-OFDM) symbol. Lastly, the corresponding DFT-s-OFDM symbol is processed for transmitting over corresponding one or more channels.

Methods, devices and systems that use a control channel to coordinate quality of data communications in software-defined heterogenous multi-hop ad hoc networks are described. In some embodiments, an example apparatus for wireless communication in a network includes performing, using a control plane, network management functions over a control channel that has a first bandwidth, implements a frequency-hopping operation, and operates at in a first frequency band, and performing, using a data plane that is physically and logically decoupled from the control plane, data forwarding functions, based on a routing decision, over at least one data channel that has a second bandwidth and operates in a second frequency band different from the first frequency band.