In examples, Radio Frequency Iterative Time-Reversal (RF-ITR) and singular value decomposition (SVD) are used by an array of nodes to characterize environment by identifying scatterer objects. The array may be ad hoc dynamic or stationary. The environment is cancelled from the RF-ITR by adjusting Time-Reversal (TR) prefilters, reducing illumination of the scatterer objects in the environment. This enables the RF-ITR process to focus on a moving target, which can then be sensed (discovered, identified, monitoring, tracked, and/or imaged). The moving target on which the RF-ITR process focuses may then be cancelled from the RF-ITR in the same way as the environment, allowing the RF-ITR to focus on another target. Multiple moving targets can thus be sensed. Defensive measures such as jamming may then be taken against the targets. The targets may be distinguished from the scatterer objects in the environment through differential, Doppler processing, and other classification techniques.

In examples, Radio Frequency Iterative Time-Reversal (RF-ITR) and singular value decomposition (SVD) are used by an array of nodes to characterize environment by identifying scatterer objects. The array may be ad hoc dynamic or stationary. The environment is cancelled from the RF-ITR by adjusting Time-Reversal (TR) prefilters, reducing illumination of the scatterer objects in the environment. This enables the RF-ITR process to focus on a moving target, which can then be sensed (discovered, identified, monitoring, tracked, and/or imaged). The moving target on which the RF-ITR process focuses may then be cancelled from the RF-ITR in the same way as the environment, allowing the RF-ITR to focus on another target. Multiple moving targets can thus be sensed. Defensive measures such as jamming may then be taken against the targets. The targets may be distinguished from the scatterer objects in the environment through differential, Doppler processing, and other classification techniques.

Aspects of the subject disclosure may include, for example, a coupling device including a first antenna that radiates a first wireless signal conveying first data; and a second antenna that radiates a second RF signal conveying the first data from the at least one transmitting device. The first wireless signal and second RF signal form a combined RF signal that is bound by an outer surface of a transmission medium to propagate as a guided electromagnetic wave substantially in a single longitudinal direction along the transmission medium. Other embodiments are disclosed.

Aspects of the subject disclosure may include, for example, a coupling device including a first antenna that radiates a first wireless signal conveying first data; and a second antenna that radiates a second RF signal conveying the first data from the at least one transmitting device. The first wireless signal and second RF signal form a combined RF signal that is bound by an outer surface of a transmission medium to propagate as a guided electromagnetic wave substantially in a single longitudinal direction along the transmission medium. Other embodiments are disclosed.

In order to efficiently compensate for effects of the Doppler shift, a receiving device includes a Doppler estimator that estimates a Doppler-shift frequency fdc of a received signal. A multiplier and an LPF detect the received signal based on a carrier frequency fc of the received signal and the Doppler-shift frequency fdc estimated by the Doppler estimator 11. A timing corrector corrects a timing T for extracting symbols of the received signal after detection by the LPF so as to track the Doppler shift. A symbol extractor extracts received symbols from the received signal after detection by the LPF at a timing corrected by the timing corrector. An adaptive equalizer estimates and determines symbols from the received symbols extracted by the symbol extractor.

Methods and apparatus for obtaining a frequency offset corresponding to a Doppler shift of transmission and/or reception frequencies between a wireless device and a network node. In one embodiment a method is performed by a wireless device for operating in a non-terrestrial network, NTN, the NTN having at least one network node and a communication satellite, wherein the at least one network node is one of a terrestrial base station and a satellite base station or satellite gateway, the method includes obtaining a frequency offset corresponding to a Doppler shift of transmission and/or reception frequencies between the wireless device and the network node and applying the frequency offset to an uplink

Methods and apparatus for obtaining a frequency offset corresponding to a Doppler shift of transmission and/or reception frequencies between a wireless device and a network node. In one embodiment a method is performed by a wireless device for operating in a non-terrestrial network, NTN, the NTN having at least one network node and a communication satellite, wherein the at least one network node is one of a terrestrial base station and a satellite base station or satellite gateway, the method includes obtaining a frequency offset corresponding to a Doppler shift of transmission and/or reception frequencies between the wireless device and the network node and applying the frequency offset to an uplink

A communications apparatus includes a radio transceiver and a processor. The radio transceiver transmits or receives wireless radio frequency signals to communicate with a first network device. The processor estimates a first Doppler frequency shift value corresponding to a first carrier frequency utilized for communicating with the first network device, and adjusts the first carrier frequency to an adjusted first carrier frequency according to the first Doppler frequency shift value and communicates with the first network device according to the adjusted first carrier frequency via the radio transceiver or adjusts a first value of a measured signal quality of the first network device to an adjusted first value according to the first Doppler frequency shift value and transmits a first measurement report with the adjusted first value via the radio transceiver to the first network device.

Aspects of the subject disclosure may include, for example, a coupling device including a first antenna that radiates a first RF signal conveying first data; and a second antenna that radiates a second RF signal conveying the first data from the at least one transmitting device. The first RF signal and second RF signal form a combined RF signal that is bound by an outer surface of a transmission medium to propagate as a guided electromagnetic wave substantially in a single longitudinal direction along the transmission medium. Other embodiments are disclosed.

Aspects of the subject disclosure may include, for example, a coupling device including a first antenna that radiates a first RF signal conveying first data; and a second antenna that radiates a second RF signal conveying the first data from the at least one transmitting device. The first RF signal and second RF signal form a combined RF signal that is bound by an outer surface of a transmission medium to propagate as a guided electromagnetic wave substantially in a single longitudinal direction along the transmission medium. Other embodiments are disclosed.