A terminal device receives a DMRS and data from a network device. The DMRS and the data undergo Alamouti coding in space domain and frequency domain, or the DMRS and the data undergo Alamouti coding in space domain and time domain, and a DMRS obtained through the Alamouti coding is mapped to a first DMRS port and a second DMRS port. A modulation symbol of the first DMRS port is related to a modulation symbol of the second DMRS port. The terminal device demodulates the data based on the DMRS. Therefore, the DMRS corresponds to a transmission scheme of the data, to help the terminal device demodulate the data. This can reduce interference estimation complexity of the terminal device.

A wireless audio system including a transmitter using multiple antenna diversity techniques for different signal types is provided. Multipath performance may be optimized, along with improved spectral efficiency of the system.

A communication apparatus includes a circuitry and a transmitter. In operation, the circuitry generates a Demodulation Reference Signal (DMRS) and generates downlink control information indicating a mapping pattern of the DMRS from a plurality of mapping patterns, and the transmitter transmits the DMRS and the downlink control information. The plurality of mapping patterns include a first mapping pattern and a second mapping pattern. Resource elements used for the DMRS of the second mapping pattern are same as a part of resource elements used for the DMRS of the first mapping pattern. A number of the resource elements used for the DMRS of the first mapping pattern is larger than a number of the resource elements used for the DMRS of the second mapping pattern.

This invention is a transmission device capable of enhancing the reception characteristics of a terminal when employing transmit diversity using two antenna ports in an ePDCCH. In a base station (100) that transmits a reference signal to a terminal (200) using two antenna ports, a setting unit (102), on the basis of the reception quality of the terminal, sets as the aforementioned two antenna ports either a first antenna port pair for which DMRS (reference signals) do not undergo mutual code multiplexing, or a second antenna port pair for which the DMRS do undergo code multiplexing. A transmitter (109) transmits the DMRS from the two antenna ports set in the setting unit (102).

A terminal device includes: a higher layer processing unit configured to set at least one first RAT and at least one second RAT by signaling of a higher layer from the base station device; and a receiving unit configured to receive a transmission signal in the first RAT and a transmission signal in the second RAT. The transmission signal in the first RAT is mapped to a resource element configured on a basis of one physical parameter for each sub frame. The transmission signal in the second RAT is mapped to a resource element configured on a basis of one or more physical parameters for each sub frame and is mapped to a resource element configured on a basis of one physical parameter in a predetermined resource included in each of the sub frames.

Methods and apparatus are provided. In an example aspect, a method of transmitting a multicarrier symbol comprising a plurality of subcarriers simultaneously from a plurality of antennas is provided. Each subcarrier is associated with a respective orthogonal matrix. The method comprises transmitting the symbol from the plurality of antennas such that, for each antenna, the symbol transmitted from each subcarrier is multiplied by an element of a respective row of the matrix associated with the subcarrier, wherein the row is associated with the antenna. The matrices are selected such that from each antenna, the symbol transmitted from at least one subcarrier is multiplied by a non-zero element, and the symbol transmitted from at least one other subcarrier is multiplied by a zero element.

Embodiments of a method in a base station configured to transmit and receive wireless signals to and from a user equipment, UE. A downlink channel response of a first UE antenna is determined, based on uplink signals received from the UE. First preceding weights are calculated based on the determined channel response of the first UE antenna. Orthogonal or quasi-orthogonal preceding weights are determined based on the first preceding weights. First and second downlink signal layers are transmitted using the first preceding weights and the orthogonal or quasi-orthogonal preceding weights.

A communications node of a mobile ad hoc network (MANET) or like multi-node network may receive a preamble and/or header portion associated with a resource allocation message (e.g., as opposed to the full message) transmitted by another network node in motion relative to the receiving node. The receiving node determines a receiver-side Doppler nulling direction (e.g., for offsetting Doppler shift associated with the motion of the transmitting node relative to the receiving node) by adjusting a receiving frequency of the preamble and/or header portion through one or more nulling frequencies, each nulling frequency associated with a nulling direction for offsetting Doppler shift due to relative motion in that direction. Based on the determination of a receiver-side Doppler nulling frequency, the receiving node can determine a velocity and direction of the relative motion between the receiving and transmitting nodes.

According to one embodiment of the present invention, a method of receiving a downlink signal, which is received by a user equipment in a wireless communication system, includes the steps of receiving a TxPowerResourceConfigList for a user equipment which is not configured with a transmission mode 10 and one or more zeroTxPowerResourceConfigLists and receiving a DCI (downlink control channel) including a PRI (PDSCH RE mapping indicator). In this case, the user equipment can recognize whether a PDSCH (physical downlink shared channel) is mapped to REs (resource elements) to which a CSI-RS is transmittable using the one or more zeroTxPowerResourceConfigLists and the PRI.

A wireless transmit receive unit (WTRU) may receive a set of candidate resources, which may be used for transmission. The WTRU may periodically perform CCA on a channel (e.g., before transmitting on the channel). When the channel is determined to be free, the WTRU may determine a resource for transmission from the candidate resources. The resource may be determined based on the time remaining in the time period. For example, when the time remaining in the time period is shorter, the WTRU may determine to transmit on a resource that comprises more frequency resources. The WTRU may determine a Multiple Input Multiple Output (MIMO) scheme based on the number of frequency resources. The WTRU may send a transmission on the resource, which may include a demodulation reference signal (DM-RS). The DM-RS may indicate the resource used from transmission to a receiver of the transmission.