Abstract: A method for generating a codebook includes applying a unitary rotation to a baseline multidimensional constellation to produce a multidimensional mother constellation, wherein the unitary rotation is selected to optimize a distance function of the multidimensional mother constellation, and applying a set of operations to the multidimensional mother constellation to produce a set of constellation points. The method also includes storing the set of constellation points as the codebook of the plurality of codebooks.

Abstract: A method embodiment includes implementing, by a base station (BS), a grant-free uplink transmission scheme. The grant-free uplink transmission scheme defines a first contention transmission unit (CTU) access region in a time-frequency domain, defines a plurality of CTUs, defines a default CTU mapping scheme by mapping at least some of the plurality of CTUs to the first CTU access region, and defines a default user equipment (UE) mapping scheme by defining rules for mapping a plurality of UEs to the plurality of CTUs.

Abstract: There is provided methods and apparatus to improve spectral efficiency in Hybrid Automated Repeat reQuest (HARQ) communications. New data and retransmission data is combined in packets using code domain multiplexing, where data layers carry data and retransmission layers carry retransmission data. This technique is leveraged to introduce Multi-Packet HARQ. The HARQ layers contain Incremental Redundancy (IR) bits to assist in the decoding of a subset of previously undecoded layers. Multiple packets are jointly decoded at the receiver. Using the properties of code multiplexing, and in particular Sparse Code Multiple Access (SCMA), the correct decoding of a subset of previously undecoded layers assists in the decoding of all previously undecoded layers. HARQ feedback for multiple packets is jointly interpreted by the receiver and the transmitter using state tables. These techniques are further leveraged to allow for Multiple-User SCMA.

Abstract: Systems and methods of low complexity SCMA/LDS detection are disclosed by performing a detection algorithm such as a Message Passing Algorithm (MPA) in a receiver only over selective sub-graphs of a corresponding full factor graph representative of multiplexed codes for the multiple access code system.

Abstract: In one embodiment, a method for blindly detecting low density activity includes receiving, by a first node from a second node, a signal and executing a joint message passing algorithm (JMPA) on the signal, where executing the JMPA includes jointly producing a decoded signal and an activity list in accordance with the decoded signal, and calculating a plurality of a priori probabilities in accordance with a plurality of log likelihood ratios (LLRs) corresponding to the signal and a plurality of decoded LLRs.

Abstract: In one embodiment, a method for blindly detecting low density spreading (LDS) active signatures including receiving, by a first node from a second node, a signal and decorrelating the signal in accordance with a signature list to obtain an active signature list. The method also includes decoding the signal in accordance with the active signature list to obtain a decoded signal.

Abstract: A method for operating a transmission point in a communications system includes receiving wideband feedback information at a first report rate, and receiving subband feedback information at a second report rate, wherein the first report rate is less than the second report rate. The method also includes performing dynamic rate selection for resource block groups (RBGs) of the communications system in accordance with the wideband feedback information and the subband feedback information.

Abstract: Disclosed herein are an active resource unit detector and a method of use thereof. An embodiment method of detecting active resource units among a plurality of potential resource units includes receiving an aggregate signal containing active pilots transmitted over the active resource units via random access transmissions. The active pilots are then detected and respectively associated with the active resource units according to a pilot-to-resource unit mapping.

Abstract: A method for link adaptation in a wireless communications system includes deriving a range of post-processing signal to interference plus noise ratio (SINR) values for a communications channel using a first layer in the communications channel available for communications, the range of post-processing SINR values derived in accordance with a channel estimate of the communications channel, interference information about the communications channel, and signature information. The method also includes selecting a modulation and coding scheme (MCS) in accordance with the range of post-processing SINR values to establish a first channel quality index (CQI) vector, adjusting the first CQI vector in accordance with information regarding operating conditions in the wireless communications system to produce an adjusted CQI vector, and transmitting the adjusted CQI vector to a second communications device.

Abstract: Embodiments are provided to enable downlink open-loop multi-user coordinated multipoint (MU-CoMP) transmission using sparse code multiple access (SCMA). In an embodiment, a network controller selects, in a cluster of multiple transmission points (TPs) and multiple user equipment (UEs), a MU-CoMP with SCMA transmission mode and a UE paring scheme for data transmission from a set of TPs to a set of UEs. The controller schedules the set of UEs for data transmission from the set of TPs, including coordinating and allocating, for each TP in the set of TPs, a plurality of SCMA layers to the UEs in accordance with the selected MU CoMP with SCMA transmission mode. The controller also determines values for control signaling based on the scheduling. The control signaling configures the set of UEs to detect the data transmission from the TPs.

Abstract: A method for data transmission by a device in a communication system includes modulating a first data stream using a codebook to produce a second data stream, wherein the codebook is in correspondence with a multi-dimensional modulation map that includes a number of distinct projections per complex dimension that is smaller than a number of modulation points of the multi-dimensional modulation map, and transmitting the second data stream over allocated resources in the communication system.

Abstract: A method for transmitting data includes mapping a first coded information bit stream intended for a first transmit antenna onto at least one first spreading sequence of a plurality of first spreading sequences to generate a first data stream, mapping a second coded information bit stream intended for a second transmit antenna onto at least one second spreading sequence of a plurality of second spreading sequences to generate a second data stream. The method also includes transmitting the first data stream and the second data stream on respective transmit antennas.

Abstract: Embodiments are disclosed for improved systems and methods for encoding and decoding information transmitted using multiple-input-multiple-output (MIMO) communication devices. Structurally sparse codes are implemented based on principles of compressive sampling. Improved detectors are also disclosed for implementing basis pursuit and basis pursuit with runner-up detection techniques.

Abstract: A method for transmitting data includes mapping a first coded information bit stream intended for a first transmit antenna onto at least one first spreading sequence of a plurality of first spreading sequences to generate a first data stream, mapping a second coded information bit stream intended for a second transmit antenna onto at least one second spreading sequence of a plurality of second spreading sequences to generate a second data stream. The method also includes transmitting the first data stream and the second data stream on respective transmit antennas.

Abstract: In a multi-access communication system having a plurality of multiplexed layers and a plurality of mobile devices, mobile devices are paired over time-frequency and space resources. Transmission power is allocated such that a total power is shared among the plurality of multiplexed layers. The plurality of multiplexed layers and rate of each of the plurality of mobile devices are adjusted according to a power and a channel quality of the mobile device. Power and rate are adjusted until a scheduling criterion such as a weighted sum-rate is maximized.

Abstract: Systems and methods can implemented to joint transmission for interference management in wireless communications. A first transmitter having M antennas can acquire a channel state information (CSI) matrix for each of a plurality of multiple-input-multiple output (MIMO) channels between a first transmitter and a plurality of receivers. The first transmitter can determine transmission ranks, wherein each of the transmission ranks corresponds to a number of one or more data streams to be transmitted from both the first transmitter and a second transmitter to a receiver of the plurality of receivers. A maximum transmission rank may be identified from the determined transmission ranks. Transmit data can be generated that include the one or more data streams to each of the corresponding plurality of receivers. A precoding matrix can be generated for the generated transmit data based, at least in part, on the acquired CSI matrix.

Abstract: Embodiments are provided herein for increasing low density signature space for multiplexed transmissions for a plurality of users. The embodiments include generating a virtual signature using a combination operation on a plurality of basic signatures. The generated virtual signatures are provisioned as basic resource units (BRUs) for transmissions for corresponding users. The combination operation is a row-wise or column-wise permutation for combining, in each of the virtual signatures, rows or columns of corresponding basic signatures. The rows or columns represent sequences of frequency bands at one time interval or sequences of allocated time intervals at one frequency band. Alternatively, the combination operation is intra-basic resource unit (BRU) hopping. The embodiments also include generating a plurality of BRU sets comprised of virtual signatures. Each of the BRU sets is provisioned for a corresponding user.

Abstract: Multi-user sparse space codes are proposed as a new transmission scheme for uplink communication over a multi-user multiple-input-multiple-output (MIMO) communication channel.

Abstract: A method for operating a receiver having multiple receive antennas to process a signal from a first affiliated transmitter and align interference from a second interfering transmitter includes providing a codebook of predefined matrices. Each predefined matrix has an identifier associated therewith. A first channel matrix and a second channel matrix are assembled for the first and the second transmitters. An equivalent direct channel matrix is determined from the first and second channel matrices, and predetermined reference vectors are selected from a plurality of predetermined vectors. A predefined matrix is selected from the codebook based upon the equivalent direct channel matrix and an identifier for the predefined matrix is fed back to the first transmitter. A signal is received and decoded using a combining matrix derived from the predetermined reference vectors and an inverse of the second channel matrix, thereby reducing interference from the interfering transmitters.

Abstract: A multi-level coding and iterative decoding scheme using sparse space codes as the inner-code and codes amenable to belief propagation decoding methods (such as low-density parity-check (LDPC) codes, turbo codes, and trellis codes) as the outer-code is proposed for MIMO communication channels.