In busy 5G and 6G networks, precise timing and synchronization are key to maintaining throughput with low fault rates. Disclosed are systems and methods for adjusting each user device's clock for proper reception, including downlink propagation delays, uplink propagation delays, round-trip propagation delays, and Doppler shifts, individually for each user device, and including any uplink/downlink asymmetries. The clock adjustment and timing advance of each user device is based on a predetermined transmission schedule for timing signals, broadcast by the base station. The Doppler shift is measured by the base station, according to uplink timing signals, and communicated to the user device in a single final timing signal. The single final timing signal is either frequency-shifted by the measured Doppler shift, or delayed proportional to the Doppler shift, either of which indicates, to the user device, how to apply the correct timing to future uplink messages.

The present disclosure discloses a method and a system for transmitting DFT-s-OFDM symbols. A data sequence for transmitting as an OFDM symbol is received as input from a data source. A reference sequence for transmitting along with the data sequence as the OFDM symbol is generated and time-multiplexed with the data sequence, to generate a multiplexed sequence. Thereafter, a Discrete Fourier Transform (DFT) operation is performed on the multiplexed sequence to generate a DFT-spread-Orthogonal Frequency Division Multiplexing (DFT-s-OFDM) symbol that is further processed for transmitting over a channel. The transmission of the reference sequence and the data sequence in a single OFDM symbol provides better bandwidth utilization and flexibility in modulation of the reference sequence and the data sequence.

Methods, systems, and devices for wireless communications are described that support frequency and time domain multiplexing for low peak-to-average waveforms with multiple streams. A user equipment (UE) may identify sets of symbols associated with different streams (e.g., multiple single-carrier discrete Fourier transform (DFT)-spread waveforms), where each stream may be associated with a low peak-to-average power ratio (PAPR). In some cases, different waveforms may be mapped to subsets of frequency resources through frequency division multiplexing (FDM). The UE may further reduce the PAPR of the multiplexed waveforms by performing time division multiplexing (TDM) across the single-carrier streams, and sets of symbols that are not used by one waveform may be used by another waveform. Frequency domain phase ramps may be applied to align the multiplexed waveforms. Signals included in an uplink transmission according to these techniques may maintain properties similar to single-carrier waveforms, including a low PAPR.

An apparatus and method for generating a broadcast signal frame including preamble for signaling injection level information. An apparatus for generating broadcast signal frame according to an embodiment of the present invention includes an injection level controller configured to generate a power reduced enhanced layer signal by reducing a power of an enhanced layer signal; a combiner configured to generate a multiplexed signal by combining a core layer signal and the power reduced enhanced layer signal; a power normalizer configured to reduce the power of the multiplexed signal to a power level corresponding to the core layer signal; a time interleaver configured to generate a time-interleaved signal by performing interleaving that is applied to both the core layer signal and the enhanced layer signal; and a frame builder configured to generate a broadcast signal frame including a preamble for signaling injection level information corresponding to the injection level controller.

Prior art includes complex clock synchronization in 5G and 6G based on precision time measurements and multiple message exchanges. Disclosed is a simpler synchronization procedure suitable for reduced-capability receivers as well as high-performance users. The base station can transmit a brief signal on a specific subcarrier, surrounded fore and aft by silent periods, and the receiver can measure the signals in the silent periods to detect intrusion of the signal into one or the other silent periods, thereby indicating a timing offset. Alternatively, the base station can transmit a brief signal spanning an interface between subsequent symbol-times, and the receiver can measure the energy received in the two symbol-times, thereby detecting an offset. In either case, and other versions disclosed, the receiver can calculate the size and direction of the clock offset by amplitude measurements, and apply a correction without further communications between the user device and the base station.

A receiver for detecting and recovering payload data from a received signal comprises a radio frequency demodulation circuit, a detector circuit and a demodulator circuit. The radio frequency demodulation circuit detects the received signal. The received signal carries the payload data as OFDM symbols in one or more of a plurality of time divided frames, each frame including a bootstrap signal, a preamble signal and a plurality of sub-frames. The demodulator circuit detects bootstrap OFDM symbols to identify communications parameters for detecting the fixed length signalling data, detects the fixed length signalling data to identify the communications parameters for detecting the variable length signalling data, detects the variable length signalling data, and uses the fixed and variable length signalling data to detect the payload data.

A wireless communication method includes sending, by a first device in a wireless network, a poll packet (32, 38, 44) for polling a second device in the wireless network. The poll packet includes an address of the second device. The second device receives and at least partially decodes the poll packet. The second device sends a response packet (36, 40, 46) in response to the poll packet. The sending of at least part of the response packet is substantially simultaneous with the receiving of at least part of the poll packet by the second device. Wireless communication systems, transmitters and receivers using the method are also described.

Methods, systems, and devices are described for hierarchical communications within a wireless communications system. An eNB and/or a UE may be configured to operate within the wireless communications system which is at least partially defined through a first layer with first layer transmissions having a first subframe type and a second layer with second layer transmissions having a second subframe type. The first subframe type may have a first round trip time (RTT) between transmission and acknowledgment of receipt of the transmission, and the second layer may have a second RTT that is less than the first RTT. Subframes of the first subframe type may be multiplexed with subframes of the second subframe type, such as through time division multiplexing.

The application discloses a communication method, a terminal device and a network device, which are suitable for determining a waveform to be used in an uplink transmission of the terminal device in various scenarios. The method includes that: a terminal device transmits first indication information to a network device, where the first indication information is used to indicate a location area in which the terminal device is currently located; the terminal device receives second indication information transmitted by the network device, where the second indication information is used to indicate a first target waveform, the first target waveform being determined by the network device from at least two optional uplink waveforms according to the location area in which the terminal device is currently located; and the terminal device performs an uplink transmission using the first target waveform.

A receiver for detecting and recovering payload data from a received signal comprises a radio frequency demodulation circuit, a detector circuit and a demodulator circuit. The radio frequency demodulation circuit detects the received signal. The received signal carries the payload data as OFDM symbols in one or more of a plurality of time divided frames, each frame including a bootstrap signal, a preamble signal and a plurality of sub-frames. The demodulator circuit detects bootstrap OFDM symbols to identify communications parameters for detecting the fixed length signalling data, detects the fixed length signalling data to identify the communications parameters for detecting the variable length signalling data, detects the variable length signalling data, and uses the fixed and variable length signalling data to detect the payload data.