A base station or an associated control entity determines when base station's air interface is threshold highly loaded or is predicted to be threshold highly loaded, and the base station responsively reduces the number of transmit antennas that the base station uses. Further, the base station or associated control entity could determine when the base station's air interface is no longer actually or predicted to be threshold highly loaded, and the base station could responsively increase the number of transmit antennas that the base station uses, such as by reverting to use a default number of antennas. Reducing the number of transmit antennas that the base station uses when its air interface is threshold highly loaded may help to increase air-interface capacity by reducing resource consumption from transmission of reference signals associated with the transmit antennas.

Provided is a transmission control apparatus that, at a first transmission timing, causes a first symbol to be transmitted from a first antenna, causes the first symbol having the same phase as the first symbol transmitted from the first antenna to be transmitted from a second antenna that is orthogonal to the first antenna and has a path to a mobile terminal that is the same as a path between the first antenna and the mobile terminal, causes a second symbol to be transmitted from a third antenna arranged parallel to the first antenna, and causes the second symbol having the inverse phase of the second symbol transmitted from the third antenna to be transmitted from a fourth antenna that is orthogonal to the third antenna and has a path to the mobile terminal that is the same as a path between the third antenna and the mobile terminal.

Disclosed is a 5G or a pre-5G communication system provided to support a higher data transmission rate than a system after a 4G communication system such as LTE. A method of a first BS supporting non-orthogonal multiple access and joint reception includes: allocating transmission resources for signal transmission of a first UE and a second UE serviced by the first BS and transmitting information on the allocated transmission resources to a second BS; transmitting the information on the allocated transmission resources to the first UE and the second UE; receiving a signal of the first UE and a signal of the second UE based on the information on the allocated transmission resources; and decoding the received signal of the first UE and the received signal of the second UE, wherein resources by which the signal of the first UE is transmitted overlap with a part of resources by which the signal of the second UE is transmitted.

A simple block coding arrangement is created with symbols transmitted over a plurality of transmit channels, in connection with coding that comprises only simple arithmetic operations, such as negation and conjugation. The diversity created by the transmitter utilizes space diversity and either time or frequency diversity. Space diversity is effected by redundantly transmitting over a plurality of antennas, time diversity is effected by redundantly transmitting at different times, and frequency diversity is effected by redundantly transmitting at different frequencies: Illustratively, using two transmit antennas and a single receive antenna, one of the disclosed embodiments provides the same diversity gain as the maximal-ratio receiver combining (MRRC) scheme with one transmit antenna and two receive antennas. The principles of this invention are applicable to arrangements with more than two antennas, and an illustrative embodiment is disclosed using the same space block code with two transmit and two receive antennas.

The present invention relates to orthogonal frequency-division multiplexing (OFDM) communication systems with four transmit antennas and one or more receive antennas, and in particular to methods for inserting scattered pilots (SPs) into the transmit signals of such OFDM systems, for estimating channel properties on the basis of the scattered pilots, a multi-antenna OFDM transmitter, and an OFDM receiver. In this context, it is the particular approach of the present invention to keep the same SP pattern like in the single-transmitter case, to partition the pilots into as many subsets as there are transmitters (transmit antennas), and to interleave these subsets both in time and in frequency. In this manner, the granularity of pilots of the same subset is reduced. This offers increased flexibility in designing the scattered pilot patterns and greater accuracy of the estimated channel properties.

Provided is a method for transmitting, by a user equipment (UE), a demodulation reference signal (DMRS) for a physical uplink shared channel (PUSCH) in a wireless communication system. A terminal receives a cyclic shift field, which indicates a first value and a second value, through a physical downlink control channel (PDCCH) from a base station, generates a first DMRS sequence and a second DMRS sequence, which are associated with a first layer and a second layer respectively, by using a first cyclic shift and a second cyclic shift, respectively, which are determined based on the first value and the second value respectively, and transmits the first DMRS sequence and the second DMRS sequence to the base station. Furthermore, the first value and the second value are separated by a maximum value corresponding to a total number of possible cyclic shifts.

A single-carrier-modulation communication system for transmitting data over a wireless link, the communication system including, on a first side of a wireless link one single-carrier-modulation receiver associated with a single antenna, on a second side of the wireless link a plurality of antennas and a plurality of single-carrier-modulation transmitters, each one of the plurality of transmitters associated with one of the plurality of antennas, the transmitters each further associated with a pre-coding filter, and the plurality of transmitters are arranged to each transmit same data via a respectively associated pre-coding filter and the associated antenna, using the pre-coding filters to perform beam-forming to the one receiver. Related apparatus and methods are also described.

A wireless transmitter has a modulator modulating an information signal of a frequency f1 by a carrier wave of a frequency f2 to output a first modulated signal, a transmitting antenna transmitting the first modulated signal using a linearly polarized wave, and a motor rotating the transmitting antenna at a frequency f3 to rotate the outgoing linearly polarized wave at the frequency f3 thereby multiplexing the first modulated signal with a linearly polarized wave component and a horizontally polarized wave component, the two components being independent of each other. A wireless receiver has diversity receiving antennas receiving the signal on a plurality of polarization planes to obtain a plurality of input signals; a path difference phase shifter compensating each of the input signals for the phase shift stemming from path differences, and a composer composing the corrected received signals.

In the present invention, disclosed is a method for uplink multi-user transmission in a wireless communication system and an apparatus therefor. Specifically, a method for performing, by a station (STA), uplink (UL) multi-user (MU) transmission in a wireless communication system comprises the steps of: receiving, from an access point (AP), a trigger frame including information for UL MU transmission; and transmitting an UL MU PPDU on the basis of the information for UL MU transmission, wherein the trigger frame is a medium access control (MAC) frame, a MAC header of the trigger frame includes a type field and a subtype field, and the type of the trigger frame may be indicated by the type field and the subtype field.

Multiple antennas at the receiver and/or transmitter are commonly used in wireless communications systems to provide diversity in order reduce fading and other effects brought about by multi-path propagation. Due to the size of hearing aids and the wavelengths of the frequencies used for communication, it is difficult to achieve what is called spatial diversity by disposing the multiple antennas at different locations. Described herein are techniques for providing polarization diversity in hearing aids using antennas with different polarizations and applying the appropriate phase shifts to the received and/or transmitted signals to improve the signal quality.