Provided is a transmitter which improves the flexibility of SRS resource allocation without increasing the amount of signaling for notifying the cyclic shift amount. In the transmitter, with regard to each basic shift amount candidate group having a basic shift amount from 0 to N−1, a transmission control unit (206) specifies the actual shift amount imparted to a cyclic shift sequence used in scrambling a reference signal transmitted from each antenna port, said specification being performed based on a table in which cyclic shift amount candidates correspond to each antenna port, and based on setting information transmitted from a base station (100). With regard to basic shift amount candidates for shift amount X, the table differentiates between an offset pattern comprising offset values for cyclic shift amount candidates corresponding to each antenna port and an offset pattern corresponding to basic shift amount candidates of X+N/2.

Certain aspects of the present disclosure relate to methods and apparatus for pilot design for Narrow-Band Internet of Things (NB-IoT). In certain aspects, the method generally includes determining at least one binary code sequence to use as a demodulation reference signal (DMRS) for a channel transmitted across one or more subframes using one or more tones within a resource block (RB) allocated to the UE for narrowband communication, and transmitting the channel including the DMRS using the one or more tones and the determined binary code sequence. In certain aspects, the binary code sequence may be determined based on a binary random sequence, such as pseudo noise (PN) or Gold sequence.

A method and apparatus for generation of orthogonal training signals for transmission in an antenna array are described. In this embodiment, a set of P training signals is generated. The generation of the P training signals includes generating a first set of Zadoff-Chu sequences, where the first set of sequences is based on a first reference Zadoff-Chu sequence and first subsequent Zadoff-Chu sequences, where each one of the first subsequent Zadoff-Chu sequences is a cyclic shift of the first reference Zadoff-Chu sequence. A second set of sequences is generated based on a second reference sequence and second subsequent sequences that are cyclic shift of the second reference sequence. The P training signals are determined based on the first set of sequences and the second set of sequences. The training signals are then transmitted through a plurality of transmit paths of a base station towards a wireless network.

A Method of scrambling reference signals, device and user equipment using the method are provided. In the method, a plurality of layers of reference signals assigned on predetermined radio resource of a plurality of layers of resource blocks with the same time and frequency resources are scrambled, the method comprising: an orthogonalizing step of multiplying each layer of reference signal selectively by one of a plurality of orthogonal cover codes (OCCs) with the same length wherein the OCC multiplied to a first layer of reference signal can be configured as different from those multiplied to other layers of reference signals; and a scrambling step of multiplying all of symbols obtained from the OCC multiplied to each of the other layers of reference signals by a symbol-common scrambling sequence wherein the symbol-common scrambling sequences can be different from each other for reference signals multiplied by the same OCC.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a receiver may receive, from a transmitter, an indication of a signature of a reconfigurable intelligent surface (RIS). The receiver may receive a signal that is transmitted by the transmitter and redirected by the RIS. The receiver may receive, from the RIS, a sequence associated with the signature of the RIS indicating that the signal is transmitted using a link associated with the RIS. Numerous other aspects are described.

Presently disclosed are systems and methods for beamforming training in WLANs. In various embodiments, there are unified MIMO beamforming training procedure, which includes a training period in which an initiator transmits multiple unified training frames for performing a transmit-beamforming training of the initiator and a receive-beamforming training of one or more responders; a feedback period in which each responder replies with a beamforming-feedback response; and an acknowledgement period during which the initiator transmits respective acknowledgement frames to the one or more responders from which responses were received. Rules for restricted random access in various slots of the feedback period may be implemented, to address response contention between multiple qualifying responders.

A Method of scrambling reference signals, device and user equipment using the method are provided. In the method, a plurality of layers of reference signals assigned on predetermined radio resource of a plurality of layers of resource blocks with the same time and frequency resources are scrambled, the method comprising: an orthogonalizing step of multiplying each layer of reference signal selectively by one of a plurality of orthogonal cover codes (OCCs) with the same length wherein the OCC multiplied to a first layer of reference signal can be configured as different from those multiplied to other layers of reference signals; and a scrambling step of multiplying all of symbols obtained from the OCC multiplied to each of the other layers of reference signals by a symbol-common scrambling sequence wherein the symbol-common scrambling sequences can be different from each other for reference signals multiplied by the same OCC.

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.

Techniques are described herein for performing channel estimation for both uplink and downlink channels. Additional reference signals may be allocated or assigned to various resource elements (REs) of a transmission time interval (TTI). The receiving device (e.g., a base station or a user equipment (UE)) may be configured to use the additional reference signals during channel estimation. The use of additional reference signals may improve the accuracy of the channel estimations. In downlink communications, a base station may allocate one or more channel state information reference signals (CSI-RSs) to a port of a UE. In uplink communications, a UE may transmit several sounding reference signals (SRSs) in a group.

Provided is a transmitter which improves the flexibility of SRS resource allocation without increasing the amount of signaling for notifying the cyclic shift amount. In the transmitter, with regard to each basic shift amount candidate group having a basic shift amount from 0 to N-1, a transmission control unit (206) specifies the actual shift amount imparted to a cyclic shift sequence used in scrambling a reference signal transmitted from each antenna port, said specification being performed based on a table in which cyclic shift amount candidates correspond to each antenna port, and based on setting information transmitted from a base station (100). With regard to basic shift amount candidates for shift amount X, the table differentiates between an offset pattern comprising offset values for cyclic shift amount candidates corresponding to each antenna port and an offset pattern corresponding to basic shift amount candidates of X+N/2.