3181 results about "Subcarrier" patented technology

Systems and methods for providing energy management utilize wireless wide-area network broadcast signals and a decentralized receiver architecture to allow customers to make informed choices with regard to energy consumption and load shedding for particular appliances. A receiver assembly embedded within an appliance receives a broadcast signal, e.g., an FM subcarrier signal, including tariff data and other electrical grid data. A processor coupled with the receiver controls the appliance in accordance with the received data and in accordance with user-defined preferences. In some embodiments, a transceiver assembly is embedded in one or more appliances in a household. Each transceiver is configured to receive broadcast signals regarding grid data, and to communicate with other appliances and/or a usage meter over a wireless personal area network. Meter data from one or more households may be aggregated and uplinked back to the energy provider or other entities.

A method and apparatus for subcarrier selection for systems is described. In one embodiment, a method for subcarrier selection for a system employing orthogonal frequency division multiple access (OFDMA) comprises partitioning subcarriers into groups of at least one cluster of subcarriers, receiving an indication of a selection by the subscriber of one or more groups in the groups, and allocating at least one cluster in the one or more groups of clusters selected by the subcarrier for use in communication with the subscriber.

A method of transmitting/receiving channel quality information (CQI) of subcarriers in an OFDM system where data is transmitted on the subcarriers via one or more transmit antennas. The subcarriers are grouped into subcarrier groups each having at least one subcarrier and further grouped into subgroups each having one or more subgroups. A user equipment generates CQIs for one or more allocated subcarrier groups and the transmit antennas or CQIs for the allocated subcarrier groups, the subgroups of the subcarrier groups, and the transmit antennas. The group CQIs and the subgroup CQIs are transmitted to a Node B in one or more physical channel frames.

A method and apparatus is disclosed herein for real-time wireless power transfer control. In one embodiment, a system comprises: an RF-energy harvesting sensor tag operable to generate a first backscatter signal and at least one base station operable to deliver RF power to the sensor tag by emitting a first waveform comprising a plurality of subcarriers, wherein the first backscatter signal is generated by the sensor tag by modulated scattering of the first waveform as incident upon the sensor tag, and further wherein the at least one base station subsequently emits a second waveform determined at least in part by a closed-loop feedback control algorithm responsive to measurements of the first backscatter signal.

Techniques for reducing peak-to-average power in multicarrier transmitters employ peak cancellation with subcarriers that are impaired by existing channel conditions. The use of Carrier Interferometry (CI) coding further improves the effectiveness of peak reduction. CI coding can also be impressed onto pulse sequences in the time domain, which enhances spectral selection and facilitates peak-power control.

Embodiments are provided for supporting variable sub-carrier spacing and symbol duration for transmitting OFDM or other waveform symbols and associated cyclic prefixes. The symbol duration includes the useful symbol length and its associated cyclic prefix length. The variable sub-carrier spacing and symbol duration is determined via parameters indicating the sub-carrier spacing, useful symbol length, and cyclic prefix length. An embodiment method, by a network or a network controller, includes establishing a plurality of multiple access block (MAB) types defining different combinations of sub-carrier spacing and symbol duration for waveform transmissions. The method further includes partitioning a frequency and time plane of a carrier spectrum band into a plurality of MAB regions comprising frequency-time slots for the waveform transmissions. The MAB types are then selected for the MAB regions, wherein one MAB type is assigned to one corresponding MAB region.

Disclosed is a MIMO-OFDM system, wherein the transmitter comprises a serial/parallel converter for converting continuously inputted symbols of the number of subcarriers to K parallel signals; a signal reproducer for reproducing K parallel signals by the number of transmit antennas L an eigenmode generator for generating eigenbeam of the reproduced signals outputted from the signal reproducer at each subcarrier, on the basis of Nf eigenbeam forming vectors which are fed back long-term and information of a best eigenbeam forming vector at each subcarrier which is fed back short-term, through the feedback device; and a plurality of inverse Fourier converters for receiving the signals outputted from the eigenmode generator and generating an OFDM symbol.

Disclosed is a method, a computer program product and a device that includes a receiver for receiving a downlink signal transmitted into a cell. The receiver is operable to obtain time, carrier frequency and cell-specific preamble synchronization to the received signal and includes a plurality of synchronization units that include a first detector to detect a frame boundary using preamble delay correlation; a second detector to detect the frame boundary with greater precision using a conjugate symmetry property over a region identified by the first detector; a cyclic prefix correlator to resolve symbol boundary repetition; an estimator, using the cyclic prefix, to estimate and correct a fractional carrier frequency offset; an operator to perform a Fast Fourier Transform of an identified preamble symbol and a frequency domain cross-correlator to identify cell-specific preamble sequences and an integer frequency offset in sub-carrier spacing. The transmitted signal may be a downlink signal transmitted into the cell from a base station that is compatible with IEEE 802.16e (WiMAX).

In some implementations, a method implemented in a user equipment UE for single carrier frequency division multiple access SC-FDMA within a wireless system includes receiving an assignment of a plurality of uplink scheduling request resources and comprising a plurality of SC-FDMA subcarriers of the wireless system. One of the plurality of uplink scheduling request resources is selected for transmission of scheduling requests. It is determined that a change in uplink scheduling request resource should be made. Upon determining that a change in scheduling request resource should be made, another of the assigned uplink scheduling request resources is selected for transmission of scheduling requests.

In a multicarrier modulation communication system, subcarriers are allocated to a plurality of users using a plurality of sets of sequential subcarriers. The plurality of sets of sequential subcarriers may be allocated for transmitting information to the plurality of users or for transmitting information from the plurality of users. A multicarrier modulation communication system and the multicarrier modulation communications device is also discussed.

A virtual cell management apparatus and method using sectors in an orthogonal frequency division multiplexing mobile communication system including a cell structure having cells each comprised of a plurality of sectors, the cells performing data communication with mobile terminals within a corresponding cell through at least one subchannel having orthogonality. The method comprises forming a virtual cell with a particular one of sectors constituting a particular cell and sectors of two other cells neighboring the particular sector; transmitting, by three base stations forming the virtual cell, an interference measurement value and a channel parameter estimation value from a mobile terminal located in the virtual cell to a base station controller that controls the virtual cell, thereby allocating wireless resource including frequency bandwidth, initial bits, subcarriers and refined bits in the virtual cell; transmitting the allocated wireless resource to the three base stations so that the base stations allocate a same subchannel to each mobile terminal located in the virtual cell; and transmitting same data over the allocated subchannel.

A method for transmitting channel quality information (CQI) from a receiver station to a transmitter station in a wireless communication system which includes diversity mode consisted of spaced apart subcarriers and band AMC mode consisted of a number of bands comprised of a predetermined number of adjacent subcarriers. The method comprises the steps of transmitting an average CINR(Carrier to Interference and Noise Ratio) value for a full frequency band if the receiver station operates in the diversity mode; transmitting a differential CINR of a predetermined number of bins if the receiver station operates in the band AMC mode.

An adaptive control system for controlling the effects of narrow to medium bandwidth interferers in a wireless communications system (e.g., wireless LAN devices) by identifying which sub-carriers in a multi-carrier system are located on frequencies that are subject to interfering signals, and using only those sub-carriers that are not subject to interference for communications between wireless communications devices.

Methods and apparatus for generating and processing a signal are disclosed. The signal may comprise a plurality of mutually orthogonal subcarriers constituting a plurality of bands. The signal may be either an optical or a radio frequency signal.

The soft handoff in an OFDMA system. If the pilot signal strength for a base station exceeds the defined threshold, the base station is added to an active set list. Subcarriers in a plurality of orthogonal frequency division multiplexing (OFDM) symbols are divided and allocated into subchannels. The OFDM symbols are divided and multiplexed. A soft handoff zone with a first dimension of the subchannels and a second dimension of the divided and multiplexed OFDM symbols is defined. The soft handoff zone have subcarriers with a subchannel definition, for example, an identical permutation.

A method and apparatus for efficiently transmitting channel quality information in an OFDM communication system using dynamic channel allocation and adaptive modulation, and determining parameters required for time-division channel quality information transmission in an asynchronous CDMA communication system are provided. In the OFDM communication system in which a plurality of subcarriers are allocated to a plurality of UEs, the subcarriers are divided into a plurality of subcarrier groups each having at least one subcarrier. Each of the UEs determines and transmits the channel quality information of each of the subcarrier groups according to predetermined transmission parameters at transmission time points that do not overlap with those of other UEs. A Node B dynamically allocates the subcarriers to the UEs and their corresponding modulation schemes according to the channel quality information.

A method for subcarrier allocation and loading for a multi-carrier, multi-subscriber system is described. At least one cluster in a first and second set of clusters of subcarriers is associated for use in communication with a first and second subscriber, respectively. Then, for each cluster associated for use in communication with the first subscriber and the second subscriber, usage of that cluster is multiplexed between the first subscriber during a first time division and the second subscriber during a second time division.

Systems and methods of scheduling sub-carriers in an OFDMA system in which a scheduler takes into account channel conditions experienced by the communication devices to optimize channel conditions. The scheduler can partition a set of sub-carriers spanning an operating bandwidth into a plurality of segments. The segments can include a plurality of global segments that each includes a distinct non-contiguous subset of the sub-carriers spanning substantially the entire operating bandwidth. One or more of the global segments can be further partitioned into a plurality of local segments that each has a bandwidth that is less than a channel coherence bandwidth. The scheduler determines channel characteristics experienced by each communication device via reporting or channel estimation, and allocates one or more segments to communication links for each device according to the channel characteristics.

A mobile communication system and method utilizing Orthogonal Frequency Division Multiplexing (OFDM) receives channel quality information (CQIs) for subcarriers through which reference signals are transmitted and subcarriers through which data signals are transmitted, in subbands, each including a predetermined number of subcarriers among a plurality of the subcarriers. The CQIs are fed back from respective receivers. Resources are dynamically assigned to the respective receivers according to the feedback CQIs, thereby enabling dynamic resource assignment with minimized signaling overhead.

Disclosed are an apparatus for Channel State Information-Reference Signal (CSI-RS) allocation and a method for CSI-RS transmission using the same in a wireless communication system. A CSI-RS for each antenna port is allocated to REs or subcarriers on a basis of a symbol or symbol axis in a subframe or Resource Block (RB), and is allocated in such a manner that a distance between neighboring CSI-RS allocation REs or subcarriers may be 3 REs or subcarriers. Accordingly, in the range of following CSI-RS transmission overhead, CSI-RSs are allocated to a time-frequency resource domain in such a manner so as to have perfect orthogonality or quasi-orthogonality according to cells or cell groups. Then, the CSI-RSs, which have been allocated to the time-frequency resource domain, are transmitted.

Methods and circuits for assigning pilot boosting factors and calculating traffic to pilot ratios in a wireless communication system. The data to be transmitted is first modulated to generate a plurality of data modulation symbols. The plurality of data modulation symbols and a plurality of reference signal symbols are mapped into transmission resources of each of a plurality of antennas in accordance with a transmit diversity scheme. The transmission resources of each of the antennas are divided into a plurality of subcarriers in a frequency domain and a plurality of time units in a time domain. Then, a power scaling factor are assigned for data modulation symbols on each of the antennas in dependence upon power levels of the reference signal symbols to maintain a fixed power level across the plurality of antennas in each time unit. Finally, the data modulation symbols and the reference signal symbols are transmitted via the plurality of antennas in accordance with the mapping scheme and the assigned scaling factors.

Frequency hopping in an IFDMA system takes place by utilizing a time-varying IFDMA modulation code. In particular, a modulator receives a symbol stream and a user specific IFDMA modulation code (bⁱ(t)). The output of the modulator comprises a signal (xⁱ(t)) existing at certain frequencies, or subcarriers. The actual subcarriers that signal xⁱ(t) utilizes is dependent upon the repetition of the symbol blocks and the particular IFDMA modulation code utilized.

A system and method for data detection in a wireless communication system wherein the system comprises a receiver for receiving spatial-subspace data transmitted over a plurality of spatial-subspace channels of a sub-carrier which may comprise at least one of coded and uncoded spatial-subspace channels. The receiver comprises a receiver weighting unit for providing receive-weighed spatial-subspace data and a data estimation unit for performing an iterative processing method on the receive-weighted spatial-subspace data to estimate output data related to the input data symbol stream. The-iterative processing method comprises successively processing data on each of the plurality of spatial-subspace channels in the receive-weighted spatial-subspace data.

A system communicates data and includes a transmitter for transmitting a communications signal that carries communications data. It includes an efficient modulator for approximating the frequencies of sine/cosine basis waveforms using complex exponential functions and adding and subtracting the complex exponential functions to generate an Orthogonal Frequency Division Multiplexed (OFDM) communications signal as a plurality of N data subcarriers that carry communications data as data symbols. A receiver receives the OFDM communications signal and includes a demodulation circuit for demodulating the OFDM communications signal using logical shifts of multiples +/−2^p based on complex exponential functions corresponding to sine/cosine basis waveform approximations to extract amplitude and phase values from a plurality of N data subcarriers as data symbols within the OFDM communications signal.

In an embodiment of the method, uplink reference signals are assigned to users in a group of cells. For example, a first constant amplitude sequence having low cyclic cross correlation is assigned to each user in a first cell of the group of cells. Here, each user is assigned the first sequence. Also, simultaneously transmitting users in the first cell are assigned to different sub-carriers. A second constant amplitude sequence having low cyclic cross correlation is assigned to each user in a second cell of the group of cells. Here, each user in the second cell is assigned the second sequence. The first sequence and the second sequence are different sequences, and the first cell and the second cell are adjacent. Also, simultaneously transmitting users in the second cell are assigned to different sub-carriers. The sub-carriers to which the simultaneously transmitting users of the second cell are assigned overlap in frequency with the sub-carriers to which the simultaneously transmitting users of the first cell are assigned.

A physiologic data acquisition system includes an analog input, a sigma-delta front end signal conditioning circuit adapted to subtract out DC and low frequency interfering signals from and amplify the analog input before analog to digital conversion. The system can be programmed to acquire a selected physiologic signal, e.g., a physiologic signal characteristic of or originating from a particular biological tissue. The physiologic data acquisition system may include a network interface modulating a plurality of subcarriers with respective portions of an acquired physiologic signal. A receiver coupled to the network interface can receive physiologic data from, and send control signals and provide power to the physiologic data acquisition system over a single pair of wires. The network interface can modulate an RF carrier with the plurality of modulated subcarriers and transmit the resulting signal to the receiver across a wireless network. An integrated circuit may include the physiologic data acquisition system. Also included are methods for acquiring physiologic data comprising the step of selectively controlling an acquisition circuit to acquire the physiologic signal.

A dual packet configuration for wireless communications including a first portion that is modulated according to a serial modulation and a second portion that is modulated according to a parallel modulation. The serial modulation may be DSSS whereas the parallel modulation may be OFDM. The first portion may include a header, which may further include an OFDM mode bit and a length field indicating the duration the second portion. The first portion may be in accordance with 802.11b to enable dual mode devices to coexist and communicate in the same area as standard 802.11b devices. The dual mode devices can communicate at different or higher data rates without interruption from the 802.11b devices. The packet configuration may include an OFDM signal symbol which further includes a data rate section and a data count section. In this manner, data rates the same as or similar to the 802.11a data rates may be specified between dual mode devices. The first and second portions may be based on the same or different clock fundamentals. For OFDM, the number of subcarriers, pilot tones and guard interval samples may be modified independently or in combination to achieve various embodiments. Also, data subcarriers may be discarded and replaced with pilot tones for transmission. The receiver regenerates the discarded data based on received data, such as using ECC techniques.

The aim of the present invention is to provide an efficient and reliable transmission/reception mechanisms for a communication system with multiple component carriers, each of which further includes physical resources such as transmission slot/symbol, subcarrier/frequency subband, code, or radiation pattern. Accordingly, the control signal of a component carrier comprises a scheduling assignment specifying for said component carrier a resource for transmission of a data signal, and an allocation map specifying that a scheduling assignment has been sent for another component carrier. Signalizing the allocation map enables detection of possibly missed scheduling assignments.

A method of wireless transmission for estimating the carrier frequency offset in a base station of a received transmission from a user equipment (UE) accessing a radio access network. The method time de-multiplexes selected symbols of a received sub-frame, computes the frequency-domain symbols received from each antenna through an FFT, de-maps the UEs selected sub-carriers for each antenna, computes metrics associated to a carrier frequency offset hypothesis spanning a searched frequency offset window, repeats these steps on subsequent received sub-frames from the UE over an estimation interval duration, non-coherently accumulates the computed metrics and selects the carrier frequency offset hypothesis with largest accumulated metric amplitude.

In an OFDMA mobile communication system in which a total frequency band is divided into a plurality of sub-carrier bands, for signal transmission, to assign sub-carriers to MSs, a BS divides the total frequency band into L sub-frequency bands. The BS detects the channel condition of each of the MSs and determines a sub-frequency band for each MS according to the channel condition among the L sub-frequency bands. The BS assigns sub-carriers in the determined sub-frequency band at a predetermined sub-carrier spacing to each MS.