Abstract: A user equipment (UE) used in a multi-user (MU)-multiple input multiple output (MIMO) orthogonal frequency division multiple access (OFDMA) system is disclosed. The UE includes a receiving unit to receive from a base station an indication of an estimate of or an upper-bound on the total number of MU-MIMO user equipments (|S|) that are scheduled on a sub-band by the base station, wherein the sub-band includes one or more resource units, a calculation unit to calculate channel quality based on the indication of the estimate of or the upper-bound on the total number of MU-MIMO user equipments, and a transmission unit to transmit to the base station an indication of the channel quality. Other methods and apparatuses also are disclosed.

Abstract: A communications method implemented in a transmission point (TP) used in a coordinated multipoint transmission and reception (CoMP) system is disclosed. The communications method comprises transmitting, to a user equipment (UE), attributers for up to four indicators indicating at least physical downlink shared channel (PDSCH) resource element (RE) mapping, and transmitting, to the UE, one of the four indicators, each of which is conveyed in 2 bits, wherein the four indicators comprises ‘00’, ‘01’, ‘10’, and ‘11’ corresponding to a first set, a second set, a third set, and a fourth set of parameters, respectively. Other methods, apparatuses, and systems are also disclosed.

Abstract: We show that for any given muting fraction, a more constrained version of the problem of interest can be optimally solved in an efficient manner. In addition, the obtained solution is also a near-optimal solution for the original problem (for the given muting ratio). This allows us provide an algorithm that offers a good solution to the original problem with a tractable complexity. We also derive a lower complexity greedy that offers good performance and a certain worst-case performance guarantee. Simulations over an example LTE HetNet topology reveal the superior performance of the proposed algorithms and underscore the benefits of jointly exploiting partial muting of the macro and load balancing.

Abstract: Methods and systems for conveying or transmitting to any given user in an OFDMA-MU-MIMO system scheduling information of other co-scheduled users to permit the user to perform error-correction on received data and/or interference reduction on its received signals. The scheduling information can include resource block assignment, modulation constellations employed, coding rates employed, power levels utilized and precoder matrix indices used. Further, the scheduling information can be conveyed in part through dedicated reference symbol layers or pilot streams. Moreover, a base station may transmit a preliminary estimate of the total number of users the base station expects to schedule, or an upper-bound on the total number of users, to the MU-MIMO users to permit the MU-MIMO users to determine preferred precoder matrix indices and indications of channel quality indices.

Abstract: A method for uplink power control implemented in a wireless communications system including one or more user equipment, a serving base station, and at least one neighboring base station is disclosed. The method comprises measuring, at each user equipment, pathloss, sending, from each user equipment to the serving base station, the pathloss, and determining, at the serving base station, uplink transmit power based on the pathloss. Other methods, systems, and apparatuses also are disclosed.

Abstract: A method implemented in a user terminal is disclosed. The method comprises obtaining known precoding matrix P of rank r and modulation and coding scheme assignments used in an original transmission, and a desired retransmission rank r?, forming an approximate channel covariance matrix, estimating a minimum mean square error receiver SINR for each layer to be retransmitted responsive to said forming, and finding a retransmission precoding matrix from a preceding codebook that maximizes a sum-rate for enabling precoding selections for retransmissions in uplink multiple-input multiple-output MIMO hybrid automatic repeat request HARQ. Other methods, apparatuses, and systems also are disclosed.

Abstract: A wireless communications method implemented in a transmission point (TP) used in a mobile communications system is disclosed. The wireless communications method includes receiving, from a user equipment (UE), short-term channel state information (short-term CSI), processing the short-term CSI, and transmitting, to another TP, the processed short-term CSI. Other methods, systems, and apparatuses also are disclosed.

Abstract: A wireless communications method implemented in a transmission point (TP) used in a mobile communications system is disclosed. The wireless communications method includes receiving, from another TP, short-term channel state information (short-term CSI), and processing the short-term CSI. Other methods, systems, and apparatuses also are disclosed.

Abstract: A method implemented in a base station used in a wireless communications system is disclosed. The method comprises having a codebook including a plurality of precoding matrices, precoding data with one of the plurality of precoding matrices, and transmitting, to a user equipment, the precoded data, wherein each precoding matrix W satisfies W=W(1)W(2), where first matrix W(1) is chosen from first codebook (1), and second matrix W(2) is chosen from a second codebook. Other apparatuses, systems, and methods also are disclosed.

Abstract: Methods are provided. A method includes determining respective weighted likelihoods corresponding to a plurality of users in a multiple-input multiple-output communication system. The method further includes forming a plurality of user groups from the plurality of users using an iterative K-means clustering technique applied to the plurality of users. The iterative K-means clustering technique is responsive to the respective weighted likelihoods.

Abstract: At a coarse time-scale, at the start of each frame the choice of TPs to be made active and users to associate with the active TPs are determined by solving an optimization problem. The inputs to the optimization problem are averaged slowly varying metrics that are relevant for a period longer than the backhaul latency. At a the fine time-scale, in each slot each active TP independently does scheduling over the set of users associated with it, without any coordination with any of the other active TPs, based on fast changing information, such as instantaneous rate or SINR estimates.

Abstract: A method and system are provided. The method includes providing transmit precoders for a multiple-input and multiple-output communication system having a plurality of transmit antennas. The plurality of transmit antennas are for forming, using precoding, a plurality of channels such that each of the plurality of channels are configurable to serve a respective one of a plurality of users. The providing step includes imposing a respective average transmit antenna power constraint on each of the plurality of transmit antennas. The providing step further includes determining a diagonal precoder responsive to applying column scaling to a downlink channel matrix having a plurality of rows and a plurality of columns. The providing step additionally includes generating, from the diagonal precoder, a weighted precoder in accordance with the respective average antenna power constraint by optimizing a weighted sum-rate obtained upon transmitting respective signals over the plurality of channels.

Abstract: A wireless communications method implemented in a network system that supports coordinated multipoint transmission and reception (CoMP) is disclosed. The wireless communications method includes informing a user equipment (UE) semi-statically of a codebook subset for each channel state information (CSI) process, wherein the UE is restricted to report an indication of a precoding matrix within the codebook subset. Other methods, apparatuses, and systems are also disclosed.

Abstract: A method for determining an optimal network utilization maximization in a communication system with wireless links in which current and coarse channel state information CSI is available from all users, along with a limited amount of fine CSI by way of a frame based entails a scheduling and feedback under which a virtual queue is associated with each user with virtual rates being determined at start of each frame and policy of each frame being determined by solving a decision process.

Abstract: A fractional frequency reuse method for assigning physical resource units of a contiguous frequency band to sectors of cells is disclosed.

Abstract: A method implemented in a wireless communications system is disclosed. The method includes determining a first candidate set of transmit beams for a wireless transmitter having a transmit antenna array and a second candidate set of receive beams for a wireless receiver having a receive antenna array, transmitting, from the wireless transmitter, each transmit beam in the first candidate set, and applying, at the wireless receiver, receive beams in the second candidate set to receive said each transmit beam in the first candidate set. Other methods, systems, and apparatuses also are disclosed.

Abstract: A method for a transmit precoder for multicast communication over a downlink in a wireless network, including: initializing a transmit precoder, a channel estimate for each user in the wireless network; updating for each user a receive filter and a slack matrix; updating the transmit precoder by solving a second order cone routine solvable in closed form; determining if a predetermined convergence is met; and outputting the updated transmit precoder responsive to the convergence criteria.

Abstract: A method implemented in a base station used in a wireless communications system is disclosed. The method comprises receiving, from a user equipment, rank indication (RI), a first precoding matrix indicator (PMI) (codebook index i1), and a second PMI, the RI and the first PMI being jointly encoded, wherein, for RI=2, values 8-15 are assigned to the joint encoding of the RI and the first PMI (IRI/PMI1). Other methods, apparatuses, and systems also are disclosed.

Abstract: A method implemented in a base station used in a wireless communications system is disclosed. The method comprises receiving, from a user equipment, rank indication (RI), a first precoding matrix indicator (PMI), and a second PMI (codebook index i2), wherein values 0-15 are assigned to the second PMI IPMI2 for RI=1 and values 0-3 are assigned to the second PMI IPMI2 for each of RI=2, RI=3, and RI=4, and wherein codebook index i2 comprises IPMI2 for RI=1. Other methods, apparatuses, and systems also are disclosed.

Abstract: A method implemented in a base station used in a wireless communications system is disclosed. The method comprises receiving, from a user equipment, rank indication (RI), a first precoding matrix indicator (PMI), and a second PMI, the RI and the first PMI being jointly encoded, wherein 5 bits are used for transmission of the jointly encoded RI and first PMI, and wherein first 8 values of values expressed by the 5 bits are used for RI=1, second 8 values of the values expressed by the 5 bits are used for RI=2, a third value of the values expressed by the 5 bits is used for RI=3, a fourth value of the values expressed by the 5 bits is used for RI=4, and remaining 14 values of the values expressed by the 5 bits are reserved. Other methods, apparatuses, and systems also are disclosed.