A communication apparatus includes a receiver and a decoder. The receiver includes a plurality of antenna elements and, in operation, receives from a base station apparatus a modulated signal mapped to one of a plurality of subframes defined in a frame corresponding to a communicable range to which the communication apparatus belongs. The plurality of subframes are defined by time-division, frequency-division, or time-and-frequency division of the frame. A maximum number of modulated signals that can be simultaneously transmitted in a subframe from the base station apparatus varies depending on the communicable range. The decoder, in operation, decodes the received modulated signal.

A method for mapping, by a base station, a channel state information (CSI)-reference signal (RS) in a wireless communication system, includes mapping the CSI-RS, for at least one antenna port, to at least one pair of resource elements (REs) per physical resource block (PRB) pair in consecutive orthogonal frequency division multiplexing (OFDM) symbols in a subframe, wherein the subframe includes two slots, and each slot includes six OFDM symbols based on an extended cyclic prefix (CP), and transmitting the CSI-RS to a user equipment (UE) via the at least one antenna port in the subframe.

A method for mapping, by a base station, a channel state information (CSI)-reference signal (RS) in a wireless communication system, includes mapping the CSI-RS, for at least one antenna port, to at least one pair of resource elements (REs) per physical resource block (PRB) pair in consecutive orthogonal frequency division multiplexing (OFDM) symbols in a subframe, wherein the subframe includes two slots, and each slot includes six OFDM symbols based on an extended cyclic prefix (CP), and transmitting the CSI-RS to a user equipment (UE) via the at least one antenna port in the subframe.

Technology for a user equipment (UE) operable to perform adaptive time division duplexing (TDD) hybrid automatic repeat request (HARQ)-ACKnowledgement (ACK) reporting is described. The UE can implement an adaptive uplink-downlink (UL-DL) configuration received from an eNodeB. The UE can decode a downlink (DL) HARQ reference configuration received from the base station for a serving cell, wherein the DL HARQ reference configuration is for the implemented adaptive UL-DL configuration. The UE can decode a reference UL-DL configuration received from the base station via a system information block (SIB). The UE can encode HARQ-ACK feedback for transmission on an uplink channel of the serving cell in accordance with the DL HARQ reference configuration. The UE can perform uplink scheduling and the HARQ-ACK feedback based on the reference UL-DL configuration received from the base station via the SIB.

Technology for a user equipment (UE) operable to perform adaptive time division duplexing (TDD) hybrid automatic repeat request (HARQ)-ACKnowledgement (ACK) reporting is described. The UE can implement an adaptive uplink-downlink (UL-DL) configuration received from an eNodeB. The UE can decode a downlink (DL) HARQ reference configuration received from the base station for a serving cell, wherein the DL HARQ reference configuration is for the implemented adaptive UL-DL configuration. The UE can decode a reference UL-DL configuration received from the base station via a system information block (SIB). The UE can encode HARQ-ACK feedback for transmission on an uplink channel of the serving cell in accordance with the DL HARQ reference configuration. The UE can perform uplink scheduling and the HARQ-ACK feedback based on the reference UL-DL configuration received from the base station via the SIB.

Methods and systems for providing data are disclosed. An optimal set of subcarriers can be determined for a data transmission when a plurality of devices have requested the data transmission. The optimal set of subcarriers can be determined based on similarities or differences between parameters assigned to subcarriers in capability profiles. Capacity loss and other information can be determined based on the similarities or the differences among corresponding parameters of the capability profiles. The data transmission can be transmitted to the plurality of devices via the optimal set of subcarriers.

Embodiments of the present invention provide a data sending and receiving method, an apparatus, and a system. The method can be executed by a microwave device, which includes: obtaining a control word (CW) and a first antenna-carrier (AC) from a common public radio interface (CPRI) frame; modulating the CW to obtain in-phase/quadrature (I/Q) data of the CW; determining a first timeslot in which the first AC does not carry antenna-carrier I/Q data; writing a preset synchronization sequence, first information, and a random number in the first timeslot to generate a second AC; and combining the second AC with the I/Q data of the CW to generate a microwave air interface frame, and sending the microwave air interface frame in a time division multiplexing manner.

An apparatus is provided, where the apparatus may include a first terminal and a second terminal to be coupled to a host via a first wire and a second wire, respectively; a rechargeable storage; and a data circuitry. The apparatus may, during a first time-period, receive power via the first wire and the second wire from the host, and store the power in the rechargeable storage, and during a second time-period, transmit data from the data circuitry to the host via the first wire and the second wire. The first and second time-periods may be non-overlapping time periods. The apparatus is to refrain from transmitting any data to, or receiving any data from, the host during the first time period.

There is provided a frame structure for a cellular communication system. According to an embodiment, there is provided a first radio frame configuration defining a frame structure of a radio frame comprising at least one sub-frame dedicated only for downlink transmission. There is also provided a second radio frame configuration defining a frame structure of a radio frame comprising at least one flexible special sub-frame configurable as either a flexible downlink sub-frame or as a flexible uplink sub-frame, wherein the flexible downlink sub-frame and the flexible uplink sub-frame both comprise an uplink part and a downlink part, and wherein both the uplink part and the downlink part carry at least one of control information and a reference signal. Amongst a set of radio frame configurations comprising at least the first and second radio frame configuration, a radio frame configuration is selected and a radio signal carrying an information element indicating the selected radio frame configuration is exchanged in order to configure the selected radio frame configuration for use in the cellular communication system.

A method and apparatus for operating a satellite system including different satellites that may belong to different types of satellite constellations. In some implementations, the satellite system may include a LEO satellite constellation and one or more non-LEO satellite constellations that can be used to increase the forward link capacity of the LEO satellite constellation, for example, by allowing an LEO satellite to offload at least some of its forward link traffic to one of the non-LEO satellites. The user terminals can dynamically switch forward link communications between a LEO satellite and a non-LEO satellite while maintaining a return link connection with the LEO satellite.