Methods, systems, and devices for wireless communications are described. A base station may determine to apply tone reservation to a downlink transmission from the base station to a user equipment (UE), and may select to rate match data of the downlink transmission around selected resource elements for the tone reservation instead of puncturing the data of the downlink transmission. The base station may transmit, to the UE, a message indicating that tone reservation is applied to the downlink transmission via rate matching, and transmit the downlink transmission including the data rate matched around the selected resource elements used for tone reservation. The UE may identify the selected resource elements used for tone reservation based on an estimation of a channel between the UE and the base station, and decode the data of the downlink transmission via rate matching around the selected resource elements used for tone reservation.

There is provided spectrum shaping of a signal. A frequency-domain representation of the signal to be spectrum-shaped is provided. The signal is associated with a set of constellation points having a minimum distance. A spectrum-shaped signal is determined by altering a proper subset of the constellation points while maintaining the minimum distance between all of the constellation points. The spectrum-shaped signal is transformed into a time-domain signal.

Aspects of the disclosure relate to techniques for peak-to-average power ratio (PAPR) reduction based on a tone reservation (TR) algorithm. For a TR algorithm, a suitable subset of tones from among a full set of tones in a given resource allocation are reserved for use as peak reduction tones (PRT). An apparatus such as a transmission/reception point receives a set of one or more PRT sequences and stores them in memory. The transmission/reception point then determines a set of PRTs based on one or more later-received PRT sequence selection parameters. Other aspects, embodiments, and features are also claimed and described.

Techniques are provided for constructing or determining a training sequence as a part of transmission preamble to minimize (or at least reduce) a peak-to-average power ratio (PAPR) at a transmitting node. In one example, a long training field (LTF) sequence of a preamble is determined that combines a set of interpolating sequences with LTF tone values. The LTF tone values may cover at least a portion of bandwidth of a first size, with each of the LTF tone values repeated for different subcarriers. The phases of tones of the LTF sequence may be rotated per bandwidth of the first size and certain tones of the LTF sequence may have a stream of values at pilot locations. For example, the phases of tones of the LTF sequence may be rotated in an effort to reduce PAPR during a transmission of the LTF sequence.

Dual sub-carrier modulation (DCM) is introduced in high efficiency (HE) WLAN. DCM is a solution to deal with narrow band interferences and for range extension. DCM can introduce frequency diversity into OFDM systems by transmitting the same information on two subcarriers separated in frequency. If DCM is applied, then the transmitter modulates the same encoded bits onto two separated subcarriers with the same or different constellation mapping schemes. DCM suffers from a high peak-to-average power ratio (PAPR). In accordance with one novel aspect, a method of transmitting and encoding a HE PPDU frame with binary phase shift keying (BPSK) DCM and lower PAPR is proposed.

Aspects relate using peak reduction tones on a supplementary uplink to reduce peak to average power ratio on the supplementary uplink. For example, when a UE elects to switch from a primary carrier (e.g., a 5G NR carrier) to an SUL carrier (e.g., in a limited coverage scenario), the UE may use a defined set of PRTs to transmit data on the SUL carrier. In some examples, PRTs may be used on multiple carriers. For example, a first set of PRTs may be defined for an SUL carrier and a second set of PRTs may be defined for another carrier.

Methods, systems, and devices for wireless communications are described. A base station may determine to apply tone reservation to a downlink transmission from the base station to a user equipment (UE), and may select to rate match data of the downlink transmission around selected resource elements for the tone reservation instead of puncturing the data of the downlink transmission. The base station may transmit, to the UE, a message indicating that tone reservation is applied to the downlink transmission via rate matching, and transmit the downlink transmission including the data rate matched around the selected resource elements used for tone reservation. The UE may identify the selected resource elements used for tone reservation based on an estimation of a channel between the UE and the base station, and decode the data of the downlink transmission via rate matching around the selected resource elements used for tone reservation.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may switch from a first bandwidth part to a second bandwidth part; and transmit a signal including one or more peak reduction tones (PRTs) in one or more locations defined by a PRT allocation for the second bandwidth part. Numerous other aspects are provided.

Wireless communication techniques that include techniques for setting power of peak reduction tones are discussed. A UE may receive a signal. The UE may set power associated with at least one peak reduction tone in accordance with a path loss between the UE and a base station. The path loss may be in accordance with the received signal. Other aspects and features are also claimed and described.

The present invention relates to an apparatus for transmitting broadcast signals, an apparatus for receiving broadcast signals and methods for transmitting and receiving broadcast signals. The method of transmitting broadcast signals includes encoding data corresponding to each of data transmission channel which carries at least one service data or service component data, building at least one signal frame including the encoded data, modulating the at least one signal frame by an OFDM (Orthogonal Frequency Division Multiplex) scheme; and transmitting the broadcast signals carrying the at least one modulated signal frame.