The present disclosure relates to the communications field, and provides a frame synchronization method, user equipment, and a base station, to implement frame time synchronization in a high-low frequency hybrid communications system. In one example method, a user equipment completes synchronization of a first frequency frame, determines a first moment of the synchronization of the first frequency frame, obtains a receive time difference, and completes synchronization of a second frequency frame according to the receive time difference and the first moment. The receive time difference is a time difference between a moment at which the user equipment receives the second frequency frame and a moment at which the user equipment receives the first frequency frame.

Disclosed is an improved implementation of a flood fill mesh network that utilizes low power and does not require any network addressing or routing protocol for network message delivery. Network messages are only communicated to a network node's correspondents using broadcast network messages over a wireless network. Network messages propagate throughout the network based on each correspondent node rebroadcasting received messages to its correspondent nodes, and so on. Coordinated synchronization across network nodes can be achieved by each network node broadcasting synchronization frames to its correspondents within a synchronization window time period and thereafter adjusting its own start time for the next synchronization period to converge synchronization. A guard band may also be utilized to account for any clock drift and signal path delays between any two communicating network nodes.

Disclosed is an improved implementation of a flood fill mesh radio network that utilizes probability forwarding for rebroadcasting network messages. The forwarding probability may be determined based on analyzing a neighbor topology map constructed by each network node relative to its neighbor nodes on the network and derived from state information supplied in synchronization frames. The forwarding probability may comprise a statistical probability that a message frame received by a network node will be forwarded to the intended destination network node by one or more of the network node's neighbor network nodes. The forwarding probability may also be based on constructing a heat map of hot nodes that are identified as those originating nodes in originating node/forwarding node pairs that are the first to forward message frames along paths in the network relative to duplicate message frames received from different originating/forwarding node pairs along different paths.

Disclosed is an improved implementation of a flood fill mesh radio network that utilizes message age disambiguation to prevent unnecessary propagation of repeated messages in the network. A digital counter may be used to generate a sequence of numbers based on counter values and the counter values may be associated with each message frame that is broadcast into the mesh network. The domain of generated sequence numbers can be divided up into low and high subdomains and the maximum number of message frames broadcast by a network node in the mesh network may be constrained so that no two messages broadcast by a network node remain circulating in the network longer than that required for the digital counter to wrap back to zero. Under this paradigm the counter values associated with each message can be compared to determine the relative age of the message frames to detect repeated messages.

Disclosed is an improved implementation of a flood fill mesh network that utilizes probability forwarding for rebroadcasting network messages. The forwarding probability may be determined based on analyzing a network topology map constructed by each network node relative to its neighbor nodes communicating on the network and derived from state information contained in synchronization frames broadcasted by the network nodes on the network. The forwarding probability may comprise a statistical probability that a message frame received by a network node will be forwarded to the intended destination network node by one or more of the network node's neighbor network nodes.

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.

Techniques for automated clock synchronization and control are discussed herein. For example, the techniques can include monitoring of transmissions for known events and identifying timing or frequencies of such events. Deviations in the timing or frequencies of the events from expected times or frequencies may indicate that wireless power transmission system and receiver clocks are not synchronized. The deviations can be used to synchronize the clock for optimum wireless power transfer. Techniques are also described for enhancing clock control mechanisms to provide additional means for managing the adjustments of the clocks, as well as for enabling wireless power transmission systems to mimic client clock offsets for effective synchronization of events (e.g., beacon signals).

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.

An embodiment of the present invention relates to a method for executing a reference signal time difference measurement (RSTD) measurement-related operation by a terminal in a wireless communication system, which is a measurement-related operation executing method comprising the steps of: receiving RSTD measurement information from two or more helper UEs (H-UEs); using the received RSTD measurement information to correct the RSTD measurement information measured by the terminal; and transmitting the corrected RSTD measurement information to a base station.

A system and method to improve the accuracy of the measurement of round trip delay in a high accuracy distance measurement (HADM) is disclosed. In one embodiment, the traditional parabolic estimation is used. However, an estimation error is used to compensate for the inaccuracy of the parabolic estimation. This correction may reduce the standard deviation of a measurement by 50% or more. In another embodiment, the parabolic estimation is not used; rather, a different estimation is used, such as an absolute value estimation. In some tests, the absolute value estimation improved the mean measurement value and reduced the standard deviation by 50%.