A wireless communication system is provided for reducing the probability that latency before data transmission increases when a mobile station that is actually in sync is judged to be out of sync. A base station causes the timing calculation part to calculate the timing advance (TA) of a transmit timing from the m.sup.th mobile station; causes the timer adaptive control part to obtain the traveling speed or the time variation in TA of the m.sup.th mobile station and, adaptively determines and outputs as the timer update information the length of the m.sup.th first timer within an M number in total of synchronization timers and the length of the second timer of the m.sup.th mobile station and update the length of the m.sup.th first timer; and transmits from the downlink transmission part a downlink signal which contains timer update information.

Devices, systems and methods for collaborative wireless communication in a wireless network are described. One example method includes performing a bidirectional communication with a reference node in the source cluster, receiving, from a destination cluster comprising a second plurality of nodes, a probe generated using a phase associated with the destination cluster, estimating, based on a propagation delay of the probe, a delay parameter, generating, based on the phase associated with the destination cluster and the delay parameter, a channel estimate, and transmitting, to each of the second plurality of nodes, a common message generated using a phase value and a delay value, wherein the phase value and the delay value are derived based on the channel estimate, and wherein the destination cluster is remotely located from the source cluster.

Monitoring and mass notification systems, such as fire alarm systems, for use in occupied structures, and more particularly to wireless monitoring and mass notification systems include wireless base units that can be modular in design. This allows horns, mini horns, strobes, and audio messaging modules (e.g., speakers) to be physically plugged into the wireless base unit creating a unit with the appearance of a single physical unit. Preferably standardized plugs are used. In some cases, visual and audio modules (i.e., notification devices) have their own battery pack or external power interface. Each wireless base unit can optionally function as a repeater if it has dual transceivers (master transceiver and slave transceiver).

A multi-point transmission system comprising a plurality of slave nodes (300) for transmitting data to a wireless receiver is described herein. An outer feedback loop and a plurality of inner feedback loops (100) connecting the plurality of slave nodes (300) to a master node (200) controls the timing skew of each slave node (300) using measurements provided by the slave nodes (300) to substantially synchronize the receipt of the transmitted data at the wireless receiver. In so doing, the solution presented herein provides improved multi-point control for any number of transmission points, which improves capacity, and solves the potential flow control problems associated with ultra-lean transmissions.

An example system comprising a first transceiver configured to receive a request airframe from a second transceiver over a wireless link, the request airframe including a first timestamp indicating a first time T1 timestamp a second time indication indicating a second time T2 that the request airframe was received, generate a respond airframe and including a third time indication indicating a third time T3 that the respond airframe is transmitted to the second transceiver, transmit the respond airframe to the second transceiver, provide a timestamp information request to second transceiver, receive a timestamp information response, the timestamp information response including a fourth time indication indicating a fourth time T4, calculate a counter offset using the first time, second time, third time and fourth time as follows:

[00001]$\mathrm{counter}.Math..Math.\mathrm{offset}=\frac{\left(\mathrm{TS}.Math..Math.1+\mathrm{TS}.Math..Math.4-\mathrm{TS}.Math..Math.3-\mathrm{TS}.Math..Math.2\right)}{2},$

calculate a phase offset based on the counter offset, and correct a phase of the first transceiver.

A system and method for cell synchronization suitable for a wireless signal including substantially identical synchronization signals that repeat in predetermined time intervals, the synchronization signals including a plurality of substantially identical symbols. For a plurality of candidate synchronization points: dividing the wireless signal into a plurality of signal segments, each equal or longer than the time interval, and each including a plurality of sub-segments having substantially same length as the symbol; performing symbol-length cross-correlations between an expected symbol and the sub-segments; performing segmented symbol-wise correlations between the cross-correlation results; calculating a cost function based on the results of the symbol-wise correlations; accumulating the cost functions across a plurality of signal segments; and selecting a coarse synchronization point from the plurality of candidate synchronization points based on the accumulated cost function; Estimating synchronization parameters e.g. time and frequency offset based on the selected synchronization point.

Systems, methods, and apparatuses for sounding reference signal (SRS) management in carrier aggregation (CA) are described. A user equipment (UE) may be scheduled for overlapping (e.g., concurrent) transmissions of SRS and uplink control or data on different cells of a CA configuration. In some cases, the SRS transmission may be dropped (e.g., the UE may refrain from transmitting a scheduled SRS). While in some cases, the UE may transmit both SRS and another uplink message in overlapping time intervals on different cells (e.g., SRS may be transmitted concurrently with another uplink message). A determination of whether to transmit or drop SRS may be based on whether the different cells have different cyclic prefix (CP) lengths or on whether the SRS is scheduled to be transmitted in a special subframe of a time division duplexing (TDD) configuration, for example.

A mobile station device that receives downlink control information which is used to selectively provide downlink scheduling or a random access order, on a physical downlink control channel from a base station device. The mobile station device also transmits a random access preamble using a random access channel to the base station device based on receiving the downlink control information which provides a random access order, where the downlink control information provides a downlink resource allocation in a case that the downlink control information is used to provide the downlink scheduling and where a preset value is set for a field of the downlink resource allocation in a case that the downlink control information is used to provide the random access order.

Disclosed are methods and apparatus for calculating sensor timing corrections at a sensor device. The methods and apparatus determine a sampling period as a number of cycles of an internal clock counted while a configured number of samples is captured in a slave device, determine a time interval between samples using an offset from a time of an observed occurrence of a hardware event on a communication link, the offset being received in a command from a master device, and adjust the time interval between samples by iterative digital approximation to correct for differences between timing of the slave device and the master device while concurrently calculating a watermark time corresponding to a sample start time configured by the master device for one or more slave devices.

Apparatus and method are provided for estimating the shortest time of arrival or the shortest round-trip time (RTT) of radio signals between communication devices in a wireless network. Filtering is performed by adaptive filters with suppressed side lobes adjustable in the time domain and widths of main lobes adjustable in the frequency domain to improve detection of signals on the shortest path of arrival or line-of-sight (LOS) path while mitigating the effects signals received from longer paths of arrival or non-line-of-sight (NLOS) paths.