Systems and methods for clock synchronization are disclosed. A client synchronization system (CSS) may transmit RF pulses to a server CSS over micrometeorite ionization trail (MMIT) channels, and may receive RF pulses from the server CSS over MMIT channels, each received RF pulse following transmitted RF pulse. The client CSS may receive from the server CSS over MMIT channels measurement data including pulse arrival times at the server CSS. The measurement and transmission data may be correlated to identify RF-pulse pairs, each pairing a transmitted RF pulse received by the server CSS with a received RF pulse received from the server CSS, both over the same MMIT. TWTT analysis may be applied to timing data the pairs to compute time offsets between a client clock and a server clock. An analytical model of clock drift may be applied to the offsets to synchronize the client clock to the server clock.

Systems and methods for clock synchronization are disclosed. A client synchronization system (CSS) may transmit RF pulses to a server CSS over micrometeorite ionization trail (MMIT) channels, and may receive RF pulses from the server CSS over MMIT channels, each received RF pulse following transmitted RF pulse. The client CSS may receive from the server CSS over MMIT channels measurement data including pulse arrival times at the server CSS. The measurement and transmission data may be correlated to identify RF-pulse pairs, each pairing a transmitted RF pulse received by the server CSS with a received RF pulse received from the server CSS, both over the same MMIT. TWTT analysis may be applied to timing data the pairs to compute time offsets between a client clock and a server clock. An analytical model of clock drift may be applied to the offsets to synchronize the client clock to the server clock.

Disclosed are passive reflector radio communications systems, such as for UHF frequencies or greater than UHF frequencies, and related deployment systems and devices that provide underground communications. Embodiments of the system include reflector elements to provide passive radio communications, structural frameworks to support and orient the reflector elements, methods for calculating reflector size, shape, and position corresponding to a desired wavelength, and deployment methods and devices to install the communication system at a desired location. The passive reflectors can be placed in a folded or otherwise compact mode, for transport into underground tunnels. Once at the desired installation location, the system can be installed, with the reflectors positioned appropriately for the radio frequencies used at the location. Some of the embodiments include any of vertical or horizontal foldable reflector poles, reflective sheets, reflective mesh sheets and/or ropes, inflatable reflective pucks, and rapid deployment systems and methods.

Disclosed are passive reflector radio communications systems, such as for UHF frequencies or greater than UHF frequencies, and related deployment systems and devices that provide underground communications. Embodiments of the system include reflector elements to provide passive radio communications, structural frameworks to support and orient the reflector elements, methods for calculating reflector size, shape, and position corresponding to a desired wavelength, and deployment methods and devices to install the communication system at a desired location. The passive reflectors can be placed in a folded or otherwise compact mode, for transport into underground tunnels. Once at the desired installation location, the system can be installed, with the reflectors positioned appropriately for the radio frequencies used at the location. Some of the embodiments include any of vertical or horizontal foldable reflector poles, reflective sheets, reflective mesh sheets and/or ropes, inflatable reflective pucks, and rapid deployment systems and methods.

A system for wireless power networking, preferably including one or more nodes, such as transmit nodes, receive nodes, relay nodes, and/or hybrid nodes. The system may function to form a power network (e.g., mesh network) configured to transfer power wirelessly between nodes of the system. A method for wireless power networking, preferably including transmitting power, controlling relay nodes, and/or receiving power, and optionally including optimizing power network operation. The method is preferably performed at (e.g., by one or more nodes of) the system, but can additionally or alternatively be performed by any other suitable system(s).

A system for wireless power networking, preferably including one or more nodes, such as transmit nodes, receive nodes, relay nodes, and/or hybrid nodes. The system may function to form a power network (e.g., mesh network) configured to transfer power wirelessly between nodes of the system. A method for wireless power networking, preferably including transmitting power, controlling relay nodes, and/or receiving power, and optionally including optimizing power network operation. The method is preferably performed at (e.g., by one or more nodes of) the system, but can additionally or alternatively be performed by any other suitable system(s).

An information transmission method and a node device. The method includes: coordinating target information with a second node device; and determining, based on the target information, working information of a third node device; where the target information includes at least one of first information, second information, feedback information for the first information, and feedback information for the second information; the working information includes identification information of the third node device; and the working information further includes at least one of the following: on/off information of switch elements of reflecting or refracting units in the third node device; a working mode of the third node device; phase related information; amplitude related information; polarization related information; and frequency related information.

An information transmission method and a node device. The method includes: coordinating target information with a second node device; and determining, based on the target information, working information of a third node device; where the target information includes at least one of first information, second information, feedback information for the first information, and feedback information for the second information; the working information includes identification information of the third node device; and the working information further includes at least one of the following: on/off information of switch elements of reflecting or refracting units in the third node device; a working mode of the third node device; phase related information; amplitude related information; polarization related information; and frequency related information.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first user equipment (UE) may transmit, to a second UE via reflection by one or more passive devices, a first reference signal (RS) that is based at least in part on a shared first key that corresponds to a configuration of the one or more passive devices. The first UE may receive, from the second UE via reflection, a second RS that is based at least in part on the first key. The first UE may generate a second key based at least in part on a measurement of the second RS. The first UE may transmit a positioning reference signal that is based at least in part on the second key and that is associated with a measurement of a range between the first UE and the second UE. Numerous other aspects are described.

Methods, systems, and devices for wireless communications are described. For instance, a first user equipment (UE) may identify a configuration for an assisting node (AN) that includes an indication of a set of time resources during which the AN is active and an indication of location information that indicates communication direction information corresponding to communications via the AN during the set of time resources. The first UE may select a time resource from the set of time resources based on the indication of location information, a location of the first UE, and information associated with a packet for transmission from the first UE to a second UE via the assisting node. The first UE may transmit the packet over the selected time resource.