Abstract: Methods and systems are disclosed for symbol sequence generation and transmission for non-orthogonal multiple access (NoMA) transmission. A NoMA signal may be generated based on: (1) a first symbol sequence, the first symbol sequence determined from a set of input bits and associated with a first MA signature within a first MA signature space; (2) a second symbol sequence determined based on the first symbol sequence, the second symbol sequence being associated with a second MA signature within a second MA signature space; and (3) a symbol-to-resource element mapping applied to the second symbol sequence to produce the NoMA signal.

Abstract: A method of transmitting includes categorizing a transmission between the first device and a second device as one of a plurality of transmission types, and selecting an air interface from a plurality of air interface candidates in accordance with the transmission as categorized. The method also includes sending the transmission to the second device using the selected air interface.

Abstract: Systems and methods for closed loop MIMO (multiple input and multiple output) wireless communication are provided. Various transmit formats including spatial multiplexing and STTD are defined in which vector or matrix weighting is employed using information fed back from receivers. The feedback information may include channel matrix or SVD-based feedback.

Abstract: Methods, devices and systems for encoding and transmitting data in a wireless communications system and, in particular, for unscheduled data transmissions including low data rate transmissions. The method for transmitting data in a wireless network includes mapping data according to a predefined sequence pattern from a group of sequence patterns to provide a spreading sequence that includes multiple non-zero elements and that is enabled to partially collide in the wireless network with other spreading sequences that have been mapped according to other sequence patterns from the group; and transmitting the spreading sequence. Multiple sequences may be received by a network node and decoded using successive interference cancellation (SIC) techniques.

Abstract: Cyclic prefix based OFDM (CP-OFDM) signals can be filtered using a digital filter whose filter length exceeds the length of a cyclic prefix in CP-OFDM symbols of the signal. In one example, the duration of the filtered CP-OFDM symbol may be expressed by the following equation: M=N+L?1, where M is the duration of the filtered CP-OFDM signal, N is a duration of the CP-OFDM signal, and L is the filter length of the digital filter. Digitally filtering the CP-OFDM signal may include convolving a filtering signal with the CP-OFDM signal. The digital filter may include a finite impulse response (FIR) filter or an infinite impulse response (IIR) filter. In some embodiments, a different digital filter may be applied to each sub-band of the CP-OFDM signal.

Abstract: A method and apparatus for improving channel estimation within an OFDM communication system. Channel estimation in OFDM is usually performed with the aid of pilot symbols. The pilot symbols are typically spaced in time and frequency. The set of frequencies and times at which pilot symbols are inserted is referred to as a pilot pattern. In some cases, the pilot pattern is a diagonal-shaped lattice, either regular or irregular. The method first interpolates in the direction of larger coherence (time or frequency). Using these measurements, the density of pilot symbols in the direction of faster change will be increased thereby improving channel estimation without increasing overhead. As such, the results of the first interpolating step can then be used to assist the interpolation in the dimension of smaller coherence (time or frequency).

Abstract: A bit-level operation may be implemented prior to modulation and resource element (RE) mapping in order to generate a NoMA transmission using standard (QAM, QPSK, BPSK, etc.) modulators. In this way, the bit-level operation is exploited to achieve the benefits of NoMA (e.g., improved spectral efficiency, reduced overhead, etc.) at significantly less signal processing and hardware implementation complexity. The bit-level operation is specifically designed to produce an output bit-stream that is longer than the input bit-stream, and that includes output bit-values that are computed as a function of the input bit-values such that when the output bit-stream is subjected to modulation (e.g., m-ary QAM, QPSK, BPSK), the resulting symbols emulate a spreading operation that would otherwise have been generated from the input bit-stream, either by a NoMA-specific modulator or by a symbol-domain spreading operation.

Abstract: A method and apparatus are provided for reducing the number of pilot symbols within a MIMO-OFDM communication system, and for improving channel estimation within such a system. For each transmitting antenna in an OFDM transmitter, pilot symbols are encoded so as to be unique to the transmitting antenna. The encoded pilot symbols are then inserted into an OFDM frame to form a diamond lattice, the diamond lattices for the different transmitting antennae using the same frequencies but being offset from each other by a single symbol in the time domain. At the OFDM receiver, a channel response is estimated for a symbol central to each diamond of the diamond lattice using a two-dimensional interpolation. The estimated channel responses are smoothed in the frequency domain. The channel responses of remaining symbols are then estimated by interpolation in the frequency domain.

Abstract: A high-order Multiple-Input-Multiple-Output (MIMO) transmitter implementing a covariance-based precoding scheme that exploits transmit channel correlation and a method of operation thereof are provided. In one embodiment, covariance-based precoding is performed at the high-order MIMO transmitter based on feedback from a remote high-order MIMO receiver regarding a covariance-based precoding matrix. The covariance-based precoding matrix is, or is derived from, a transmit channel correlation matrix determined by the high-order MIMO receiver for the high-order MIMO transmitter. The covariance-based precoding provides a beam-forming effect when there is a relatively high degree of transmit channel correlation, thereby improving performance of the high-order MIMO transmitter. Further, because changes in the transmit channel correlation occur relatively slowly over time, feedback overhead requirements are substantially reduced as compared to that required for traditional MIMO precoding schemes.

Abstract: Spatial multiplexing and transmit diversity can improve the capacity of a wireless communication system. The system and method adapts communication schemes for communication systems with multiple antennas utilizing at least two transmission modes. The at least two transmission modes can, but are not necessarily, used for uplink communications. The two transmission modes may be chosen from the group consisting of a single antenna mode, a diversity mode a spatial multiplexed mode and a mixed diversity and spatial multiplexed mode. The at least two transmission modes may involve adaptation among multiple transmitters. At least one receiver may indicate a transmission mode to be used by a transmitter for a subsequent transmission. A transmitter may determine a transmission mode to be used for a subsequent transmission. The transmission mode can be based on channel sounding.

Abstract: Methods and systems are provided that enable an OFDM transmitter to be used for transmitting conventional OFDM or a form of transformed OFDM. A technique is provided for transforming a coded and modulated sequence of samples prior to an IFFT that enables the transformed sequence of samples to be transmitted using conventional OFDM or transformed OFDM. The selection of a transform function for transforming the coded and modulated sequence of samples may be based on optimizing the transform function for particular operating conditions between the transmitter and receiver. In some embodiments of the invention OFDM and time transformed OFDM are multiplexed in time and/or frequency in a transmission frame. In some embodiments of the invention a pilot pattern is provided in which the pilot are sent using OFDM and data is sent using OFDM and/or transformed OFDM.

Abstract: The present invention employs a pilot scheme for frequency division multiple access (FDM) communication systems, such as single carrier FDM communication systems. A given transmit time interval will include numerous traffic symbols and two or more short pilot symbols, which are spaced apart from one another by at least one traffic symbol and will have a Fourier transform length that is less than the Fourier transform length of any given traffic symbol. Multiple transmitters will generate pilot information and modulate the pilot information onto sub-carriers of the short pilot symbols in an orthogonal manner. Each transmitter may use different sub-carriers within the time and frequency domain, which is encompassed by the short pilot symbols within the transmit time interval. Alternatively, each transmitter may uniquely encode the pilot information using a unique code division multiplexed code and modulate the encoded pilot information onto common sub-carriers of the short pilot symbols.

Abstract: Systems and methods for OFDM channelization are provided that allow for the coexistence of sub-band channels and diversity channels. Methods of defining diversity sub-channels and sub-band sub-channels are provided and systematic channel definition and labeling schemes are provided.

Abstract: A method of transmitting includes categorizing a transmission between the first device and a second device as one of a plurality of transmission types, and selecting an air interface from a plurality of air interface candidates in accordance with the transmission as categorized. The method also includes sending the transmission to the second device using the selected air interface.

Abstract: System and method embodiments are provided for channel sounding in a frequency division duplex (FDD) system. The embodiments enable a transmission point (TP) to determine channel information about a downlink channel from an uplink channel sounding signal received on the downlink channel frequency band during a time window reserved for uplink channel sounding on the downlink channel frequency band. In an embodiment, a method in a controller includes determining with the controller a schedule for an uplink sounding window in a downlink frequency band, wherein the uplink sounding window comprises a transmission window in at least a partial downlink frequency band that is reserved for uplink channel sounding, instructing a TP to signal the schedule to at least one wireless device in a coverage area of the TP, receiving a channel sounding signal in the downlink frequency band, and obtaining downlink channel state information from the channel sounding signal.

Abstract: Systems and methods are disclosed herein for an enhanced Multimedia Broadcast Multicast Service (MBMS) in a wireless communications network. In one embodiment, a number of base stations in a MBMS zone, or broadcast region, accommodate both Spatial Multiplexing (SM) enabled user elements and non-SM enabled user elements. In another embodiment, a number of base stations form a MBMS zone, or broadcast region, where the MBMS zone is sub-divided into an SM zone and a non-SM zone. In another embodiment, the wireless communications network includes multiple MBMS zones. For each MBMS zone, base stations serving the MBMS zone transmit an MBMS zone identifier (ID) for the MBMS zone. The MBMS zone ID may be used by a user element for decoding and/or to determine when to perform a handoff from one MBMS zone to another.

Abstract: A mobile rustproofing washing system includes a receptacle, a control module, a water supply module, a filtration module and a washing module. The receptacle is removably disposed on a mobile carrier. The control module is disposed in the receptacle. The water supply module is disposed in the receptacle and includes a front water tank and a rear water tank. The filtration module is connected to the front water tank and the rear water tank. The filtration module receives and filters water from the front water tank. The filtered water is stored in the rear water tank. The washing module connects with the rear water tank and receives water therefrom, so as to carry out a washing process. Therefore, the mobile rustproofing washing system is quick to mount/demount and easy to use, thereby having high mobility.

Abstract: A method of transmitting includes categorizing a transmission between the first device and a second device as one of a plurality of transmission types, and selecting an air interface from a plurality of air interface candidates in accordance with the transmission as categorized. The method also includes sending the transmission to the second device using the selected air interface.

Abstract: Aspects of the present disclosure provide a scheme for generating a multiple access (MA) signal that include mapping each of at least one stream of bits to generate a set of modulated symbols and transmitting the set of modulated symbols. The spreading signatures that are selected to map the at least one stream of bits are selected, at least in part, based on a set of compatibility rules. The spreading involves mapping each stream of bits using a respective spreading signature from a set of spreading signatures to generate a respective set of modulated symbols, wherein real spreading signature components of the spreading signatures are orthogonal to each other and imaginary spreading signature components of the spreading signatures are orthogonal to each other.

Abstract: In some embodiments of the invention, OFDM symbols are transmitted as a plurality of clusters. A cluster includes a plurality of OFDM sub-carriers in frequency, over a plurality of OFDM symbol durations in time. Each cluster includes data as well as pilot information as a reference signal for channel estimation. In some embodiments, a plurality of clusters collectively occupy the available sub-carrier set in the frequency domain that is used for transmission. In some embodiments of the invention data and/or pilots are spread within each cluster using code division multiplexing (CDM). In some embodiments pilots and data are separated by distributing data on a particular number of the plurality of OFDM symbol durations and pilots on a remainder of the OFDM symbol durations. CDM spreading can be performed in time and/or frequency directions.