Systems, apparatuses, and methods for implementing asynchronous feedback training sequences are described. A transmitter transmits a training sequence indication to a receiver via a communication channel including a plurality of data lines. The training sequence indication includes a bit sequence to indicate the beginning of a training sequence. The indication includes a transition from a zero to a one at the midpoint of a supercycle of N clock cycles in length, followed by a predetermined number of ones. The training sequence indication is then followed by a test pattern. The beginning of the test pattern occurs at the end of a supercycle. The receiver determines if there are any errors in the received test pattern, and then sends feedback to the transmitter that indicates whether any errors were detected. Responsive to receiving the feedback, the transmitter alters delay settings for one or more of the data lines.

Techniques, schemes and examples pertaining to sequence design for synchronization and device identification in mobile communication systems are described. A processor of an apparatus generates a set of root sequences and also generates a set of signature sequences from the set of root sequences. The processor then transmits a signal comprising one or more of the signature sequences to a receiving device via a wireless channel. Each signature sequence of the set of signature sequences identifies the apparatus.

A method and system of mud pulse telemetry uses a preamble having a number of periods of a synchronization sequence followed by a single period of a channel estimation sequence. The synchronization may be characterized by a generally flat frequency spectrum, and the channel estimation sequence may be characterized by a low cross-correlation with said synchronization sequence. The sequences may be generated from a set of nonrepeating discrete sequences. The preamble may be suitable for both sequence detection and channel estimation, satisfy all the physical and/or electronic constraints of the system, and allow for fast convergence of an adaptive channel tracking or equalization system.

Advanced detectors for vector signaling codes are disclosed which utilize multi-input comparators, generalized on-level slicing, reference generation based on maximum swing, and reference generation based on recent values. Vector signaling codes communicate information as groups of symbols which, when transmitted over multiple communications channels, may be received as mixed sets of symbols from different transmission groups due to propagation time variations between channels. Systems and methods are disclosed which compensate receivers and transmitters for these effects and/or utilize codes having increased immunity to such variations, and circuits are described that efficiently implement their component functions.

The present application relates to a method of generating a downlink frame. The method of generating the downlink frame includes: generating a first short sequence and a second short sequence indicating cell group information; generating a first scrambling sequence and a second scrambling sequence determined by the primary synchronization signal; generating a third scrambling sequence determined by the first short sequence and a fourth scrambling sequence determined by the second short sequence; scrambling the short sequences with the respective scrambling sequences; and mapping the secondary synchronization signal that includes the first short sequence scrambled with the first scrambling sequence, the second short sequence scrambled with the second scrambling sequence and the third scrambling sequence, the second short sequence scrambled with the first scrambling sequence and the first short sequence scrambled by the second scrambling sequence and the fourth scrambling sequence to a frequency domain.

The present invention provides a preamble that is inserted into an OFDMA frame and has a common sequence for all the base stations participating in a transmission. The subscriber station performs fine synchronization using the common sequence on the common preamble, and the resulting peaks will provide the locations of candidate base stations. The base station specific search is then performed in the vicinities of those peaks by using base station specific pseudo-noise sequences. With this two stage cell search, the searching window is drastically reduced. The preamble is matched to known values by a respective receiver to decode the signals and permit multiple signals to be transferred from the transmitter to the receiver. The preamble may comprise two parts, Preamble-I and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems.

A method for modifying a communication signal for transmission from a source to a destination includes identifying, by data processing hardware, a target platform for communication with a communication device. The method includes establishing a communication connection between the target platform and the communication device and identifying an available communication channel for communicating data between the target platform and the communication device. The method also includes modifying a communication signal by multiplying the communication signal with a pseudo random noise spreading code. The method also includes causing transmission of the modified communication signal from the communication device to the target platform through the available communication channel. The modified communication signal is transmitted below a thermal noise of the available communication channel.

The present invention provides a preamble that is inserted into an OFDMA frame and has a common sequence for all the base stations participating in a transmission. The subscriber station performs fine synchronization using the common sequence on the common preamble, and the resulting peaks will provide the locations of candidate base stations. The base station specific search is then performed in the vicinities of those peaks by using base station specific pseudo-noise sequences. With this two stage cell search, the searching window is drastically reduced. The preamble is matched to known values by a respective receiver to decode the signals and permit multiple signals to be transferred from the transmitter to the receiver. The preamble may comprise two parts, Preamble-I and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems.

A time differential digital circuit can detect a time difference between first and second event signals. The time difference measurement can be calibrated to account for transmission path delays. The time differential digital circuit can be implemented using field programmable gate array transceivers.

Methods and systems are described for communication of data over a communications bus at high speed and high pin efficiency, with good resilience to common mode and other noise. Pin efficiencies of 100% may be achieved even for bus widths of four or fewer wires. Information to be transmitted is encoded as words of a vector signaling code, each word comprising multiple values transmitted as a group over the communications bus. Subsets of the vector signaling code have distinct group characteristics, which are discernable on transmission and are used to facilitate decoding on reception.