Abstract: Systems and methods for group management in machine-to-machine networks are provided. Network nodes in a network group are divided into sub-groups and a group information register, which includes a listing of the nodes in the group, is divided into an equal number of partitions. The partitions are distributed to the sub-groups such that each node in a given sub-group receives the same partition. The partitions are accompanied by references to network nodes of other sub-groups (termed “anchor nodes”) that have a copy of another partition of the group information register. When a new network head takes over the network group, it is able to use the available partitions to determine which partitions are missing and which nodes hold copies of the missing partitions. The group head can wake up the missing nodes and obtain the missing partition copies, thereby generating a complete copy of the group information register.

Abstract: A communications device and receiver system and method to efficiently distribute functions among radio frequency (RF), analog front end (AFE) and baseband modules for ultra-low power consumption comprising a wideband receiver subsystem selectively coupled to a signal input receiving a first frequency band, a narrowband received subsystem selectively coupled to the signal input receiving a second frequency band and, a controller configured to monitor the first frequency band using the first receiver subsystem and if a wake up signal is detected using the first receiver subsystem, connect the second receiver subsystem to the signal input and tune the second receiver subsystem to a channel transmitting the wake up signal, the wake up signal including channel selection information defining the channel for subsequent communications. Wherein, the two frequency bands overlap and center on different frequencies.

Abstract: An efficient method and transceiver architecture combines elements to enable and facilitate the low power operation of a communications device; the combination of design elements, features, and functionalities are efficiently distributed among RF, APE, and baseband modules in order to exploit opportunities that can serve the goal of low or ultra low power consumption.

Abstract: A method for determining an overlap and add length estimate comprises determining a plurality of correlation values of a plurality of ordered frequency domain samples obtained from a data frame; comparing the correlation values of a first subset of the samples to a first predetermined threshold to determine a first edge sample; comparing the correlation values of a second subset of the samples to a second predetermined threshold to determine a second edge sample; using the first and second edge samples to determine an overlap and add length estimate; and providing the overlap and add length estimate to an overlap and add circuit.

Abstract: A variation on conventional DPSK binary modulation schemes is provided. One modulation scheme uses 3?/8 differential binary phase shift keying (3?/8-DBPSK) where one symbol is transmitted by phase change of 3?/8 radians and the other symbol is transmitted by phase change of ?5?/8 radians. Alternatively, this can be thought of as adding a constant 3?/8 radians to the symbol angle for every bit modulated by conventional DBPSK. In another example, assume a first and second symbols, k?1 and k, respectively, are sent. Where k is the same symbol as k?1, a phase rotation of 3?/8 radians from the kth symbol is used to represent the symbol at k?1; and where the k?1 symbol is the opposite of the kth symbol, its rotation 11?/8 radians from the kth symbol. Other modulation schemes using other phase rotations can be provided.

Abstract: A system and method is provided for varying the apparent distance of a virtual image projected by a head-mounted display. The distance between the user and an object being viewed by the user is determined. Then, the focal distance of an eyepiece optical system in the head-mounted display is adjusted to provide a virtual image at an apparent distance that corresponds to the determined distance. The user thereby experiences an approximately seamless overlay in sharp focus of the virtual image from the display and the three-dimensional binocular image being viewed. For example, when viewing a movie screen, or other object at infinity, the focal length is adjusted to provide a virtual image at or near optical infinity. Likewise, when reading a book, or inspecting another object in close proximity, the focal length is adjusted to provide the virtual image at a nearby apparent distance.

Abstract: The present invention is directed to a system and method for channel estimation for a communication channel such as, for example, that found in a wireless communication network. One or more channel estimates or channel observables can be combined to compute a refined channel estimate, for example, when the channel estimates or channel observables are from the same channel.

Abstract: Phase tracking in an OFDM symbol comprises determining a sufficient statistic for CFO and SFO estimation from a differential metric between a current OFDM symbol and a previous OFDM symbol transmitted on the same frequency band. The sufficient statistics corresponding to positive pilot tones are combined with those corresponding to negative pilot tones to estimate the CFO and SFO.

Abstract: A master device selects a channel from a band of channels for communications with a slave device. The master transmits information identifying the selected to the slave device using a packet modulated as a series of energy pulses on the selected channel. The slave device performs wideband energy detection on the band of channels and receives the modulated pulses. The slave device decodes the modulated pulses to retrieve the selected channel, and tunes to the selected channel for further communications.

Abstract: Various embodiments of the systems and methods described herein may be used to compute a minimum variance unbiased estimator by receiving a first OFDM signal at a pilot tone, receiving a second OFDM signal sent in the same frequency band and determining a differential phase metric between the first OFDM signal and the second OFDM signal. In some embodiments, the differential phase metric may be used to diversity combine synchronization statistics. In various embodiments, the differential phase metric may be used to detect a narrow-band interference.

Abstract: Various embodiments of the systems and methods described herein may be used to compute a minimum variance unbiased estimator by receiving a first OFDM signal at a pilot tone, receiving a second OFDM signal sent in the same frequency band and determining a differential phase metric between the first OFDM signal and the second OFDM signal. In some embodiments, the differential phase metric may be used to diversity combine synchronization statistics. In various embodiments, the differential phase metric may be used to detect a narrow-band interference.

Abstract: Various embodiments of the systems and methods described herein may be used to compute a minimum variance unbiased estimator by receiving a first OFDM signal at a pilot tone, receiving a second OFDM signal sent in the same frequency band and determining a differential phase metric between the first OFDM signal and the second OFDM signal. In some embodiments, the differential phase metric may be used to diversity combine synchronization statistics. In various embodiments, the differential phase metric may be used to detect a narrow-band interference.

Abstract: A system for transmitting data over a MIMO channel has a transmitter and a receiver. In the transmitter, the input data is encoded over at least two pipes by a concatenation of at least two constituent signal-space encoders. Each constituent encoder is used to generate, in response to the input data, a sequence of symbols from a channel alphabet having at least one dimension. Each symbol of the channel alphabet includes at least one complex symbol having real and imaginary coordinates. The transmitter interleaves the coordinates of the sequence of channel alphabet symbols, and transmits (from at least two transmit antennas) the interleaved coordinates. Preferably, each constituent encoder maximizes a minimum coordinate-wise Hamming distance between members of all valid pairs of symbol sequences, maximizes a minimum Euclidean distance between members of all valid pairs of different codewords, and obeys an equal eigenvalue criterion.

Abstract: Various embodiments of the systems and methods described herein may be used to compute a minimum variance unbiased estimator by receiving a first OFDM signal at a pilot tone, receiving a second OFDM signal sent in the same frequency band and determining a differential phase metric between the first OFDM signal and the second OFDM signal. In some embodiments, the differential phase metric may be used to diversity combine synchronization statistics. In various embodiments, the differential phase metric may be used to detect a narrow-band interference.

Abstract: The present invention is directed to a system and method for channel estimation for a communication channel such as, for example, that found in a wireless communication network. One or more synchronization and channel estimate symbols can be combined to compute a refined channel estimate.

Abstract: A system and method of transmitting and processing pilot signals includes decorrelating a pilot tone that conveys a pilot signal, performing a channel estimation based on the decorrelated pilot tone to calculate estimated channel values and positioning the estimated channel values consistent with their order in subsequent transmission units. In one embodiment, the decorrelation comprises an interleaving operation. In another embodiment, the decorrelation occurs during a channel estimation stage. The decorrelation can be performed during a channel estimation stage by interleaving and deinterleaving pilot signals in the receiver.

Abstract: In a MIMO delay spread (OFDM) system or a MIMO single carrier (non-OFDM) system wherein a transmitter transmits signals to a receiver through multipath fading channels, an equivalent frequency-domain MIMO multipath channel matrix is used to estimate the maximum mutual information regarding the relationship between transmitted signals and received signals. It is possible to compute the upper bound of the maximum mutual information at least based on the total energy of all resolvable paths in the fading channels. The upper bound or the changes in the upper bound can be used to adjust the transmission parameters used in data transmission. The transmission parameters include the modulation order in the modulation process, the code rate and the puncturing rate.

Abstract: Various embodiments of the systems and methods described herein may be used to compute a minimum variance unbiased estimator by receiving a first OFDM signal at a pilot tone, receiving a second OFDM signal sent in the same frequency band and determining a differential phase metric between the first OFDM signal and the second OFDM signal. In some embodiments, the differential phase metric may be used to diversity combine synchronization statistics. In various embodiments, the differential phase metric may be used to detect a narrow-band interference.

Abstract: Apparatus, and an associated method for a sending station operable in a communication system having a communication channel susceptible to fading, such as quasistatic fading. Transmission diversity of symbols to be sent by the sending station is increased without necessitating a corresponding increase in the bandwidth required to communicate the symbols.

Abstract: Various embodiments of the systems and methods described herein may be used to compute a minimum variance unbiased estimator by receiving a first OFDM signal at a pilot tone, receiving a second OFDM signal sent in the same frequency band and determining a differential phase metric between the first OFDM signal and the second OFDM signal. In some embodiments, the differential phase metric may be used to diversity combine synchronization statistics. In various embodiments, the differential phase metric may be used to detect a narrow-band interference.