Methods, systems, and devices for wireless communications are described. A base station may identify time and frequency resources for a physical downlink shared channel (PDSCH) to be transmitted to a user equipment (UE) in a first transmission time interval (TTI). The base station may transmit configuration information for a control channel search space set in a second TTI. The second TTI may precede the first TTI. The configuration information may include an indication of an absence of a physical downlink control channel (PDCCH) transmission to send in the control channel search space set indicating the identified time and frequency resources for the PDSCH, and a set of time and frequency resources for the control channel search space set. The UE may receive the configuration information and identify the time and frequency resources allocated for the PDSCH in the second TTI, and receive the PDSCH transmission in the second TTI.

A method for channel estimation, performed by a wireless transmit/receive unit (WTRU), includes: receiving a plurality of input signals, generating a plurality of sensing matrices for the input signals, generating an augmented sensing matrix and an augmented observation vector according to the sensing matrices and the input signals, estimating a plurality of channel delay parameters according to the augmented sensing matrix and the augmented observation vector, and estimating channel information according to the channel delay parameters.

This disclosure relates to techniques for performing ranging wireless communication in a secure manner. A first wireless device may receive a plurality of independent sequences from a second wireless device. The first wireless device may perform a combined channel estimate using the sequences. The first wireless device may estimate the distance (or angle/direction, among various possibilities) between the two devices based on the combined channel estimate.

A method for channel estimation, performed by a wireless transmit/receive unit (WTRU), includes: receiving a plurality of input signals, generating a plurality of sensing matrices for the input signals, generating an augmented sensing matrix and an augmented observation vector according to the sensing matrices and the input signals, estimating a plurality of channel delay parameters according to the augmented sensing matrix and the augmented observation vector, and estimating channel information according to the channel delay parameters.

A method, system, and device for transmitting a preamble signal and for signal measurement, for use in solving the problem found in the prior art that the transmission power of each antenna unit is greatly reduced as a result that each antenna unit transmits one preamble signal and that the complexity of a user equipment is increased when the antenna units are of a great number. The method of embodiments of the present disclosure comprises: a network side device transmits to the user equipment determined CSI feedback configurations, where one CSI feedback configuration corresponds to one CSI-RS resource, and the preamble signal corresponding to each port of the one CSI-RS resource is transmitted via one set of antenna unit corresponding to the port. Employment of the solution of the embodiments of the present disclosure increases the transmission power of the antenna units, allows the user equipment to correctly perform signal measurement, increases the performance of data transmission, and reduces the complexity of the user equipment when the antenna units are of a great number.

A reception apparatus includes reception circuitry and decoding circuitry. The reception receives a signal including a legacy header field, an enhanced directional multi-gigabit (EDMG) header field, and a data field. The decoding circuitry decodes data included in the data field of the received signal. The legacy header field includes a Length field comprising multiple bits. The reception apparatus is an EDMG terminal, and a subset of the multiple bits of the Length field included in the legacy header field is used to indicate bandwidth over which the signal is transmitted. Remaining bits of the Length field included in the legacy header field are used to indicate data length of the received signal.

This disclosure describes methods, apparatus, and systems related to a channel estimation field (CEF) for various standards, for example, the 802.11ay standard, for single carrier (SC) MIMO channel estimation. In one embodiment, the CEF can use Golay complementary sequences. In another embodiment, the Golay complementary sequences can be defined similar to Golay complementary sequences definitions that can be found in various legacy standards, for example, the legacy 802.11ad standard. Various embodiments of the disclosure can allow channel estimation in the time domain and/or frequency domain, having small or negligible inter-stream interference. Various embodiments of the disclosure can enable an extendable structure for various MN MIMO configurations, where M and N are positive integers.

A method for channel estimation, performed by a wireless transmit/receive unit (WTRU), includes: receiving a plurality of input signals, generating a plurality of sensing matrices for the input signals, generating an augmented sensing matrix and an augmented observation vector according to the sensing matrices and the input signals, estimating a plurality of channel delay parameters according to the augmented sensing matrix and the augmented observation vector, and estimating channel information according to the channel delay parameters.

A method for estimating noise in a channel impulse response measurement. In some embodiments, the method includes calculating a first average energy, the first average energy being an average energy of a sequence of time-domain samples of the channel impulse response measurement; setting a detection threshold; identifying a first subset of the sequence of time-domain samples, each element of the first subset of the sequence of time-domain samples having an energy less than the detection threshold; and calculating a second average energy, the second average energy being an average energy of the first subset of the sequence of time-domain samples.

The present invention discloses various improvements to multi-user multiple-input multiple-output orthogonal frequency division multiplexing (MU-MIMO-OFDM) wireless communication systems. In one aspect there is disclosed an efficient and accurate channel estimation method and system using locally consecutive pilot sub-carriers. In another aspect there is disclosed an efficient channel feedback method and system by applying a discrete cosine transform to channel coefficients. In another aspect there is disclosed an efficient method and system to calculate a part of the channel inverse by interpolation. These aspects can be used in combination to improve the MU-MIMO-OFDM system.