Techniques providing opportunistic frequency switching for frame based equipment (FBE), such as may be configured to minimize opportunistic frequency switching delay in FBE new radio (NR) unlicensed (NR-U) networks and/or to provide frequency diversity FBE access based on offset sequences of medium sensing occasions for the carrier frequencies are disclosed. Within the FBE mode network, a base station may configure a pattern of sensing locations in each frame for each frequency transmission unit of the plurality of frequency transmission units, wherein an inter-unit delay of sensing locations between a first frequency transmission unit and a next adjacent frequency transmission unit and between a last frequency transmission unit and the first frequency transmission unit is a fixed duration. Opportunistic frequency switching of embodiments may utilize the medium sensing locations for opportunistically switching between a sequence of the frequency transmission units for implementing frequency diversity FBE access.

The present disclosure provides a method of measuring a small cell based on a discovery signal. The method may include the step of receiving a discovery signal measurement timing configuration (DMTC) for a neighboring small cell. In this step, the DMTC may include DMTC periodicity information and information on a discovery signal occasion section. The information on the discovery signal occasion section may indicate one or more sub-frames in which the discovery signal occurs. The method may include the step of measuring the neighboring small cell for a measurement gap in the case where the neighboring small cell operates at a frequency that is different from a serving cell.

An embodiment of the present invention relates to a method for transmitting a synchronization signal in a wireless communication system, the method comprising the steps of: generating a synchronization signal on the basis of a cell ID which is determined depending on whether a terminal for transmitting the synchronization signal is a terminal located outside of a coverage; and transmitting the synchronization signal.

The present invention provides a signal sending apparatus, a signal detection apparatus, a signal sending and detection system, a signal sending method, and a signal detection method. The apparatus determines a time unit that is in each time window and that is used to transmit a synchronization signal, and transmits the synchronization signal in the determined time unit in each time window. Therefore, a synchronization signal is always located in a time unit that has a fixed location in each time window, so that a device at a receive end needs to perform detection only in a fixed time unit in each time window, thereby reducing complexity of designing and detecting the synchronization signal.

A method and apparatus provides a determination of a set of sequence values to be used as synchronization signal sequences, the set of sequence values having a predetermined length. Each sequence value in the set is based upon a first maximum length sequence having a first cyclic shift, and is based upon a second maximum length sequence having a second cyclic shift. For at least one group of possible sequence values from the determined set, where a value of a cyclic shift difference between the second cyclic shift of the second maximum length sequence and the first cyclic shift of the first maximum length sequence upon which each of the possible sequence values in the group are based are equal, a cyclic shift difference between the respective first cyclic shift value of the first maximum length upon which each of the possible sequence values in the group are based for any two of the possible sequence values in the group are larger than or equal to a threshold value, where the threshold value is determined based on an expected maximum carrier frequency offset value. The method further includes assigning each one of the determined set of sequence values to respective at least one communication target of a plurality of communication targets.

Certain aspects of the present disclosure relate to methods and apparatus for generating synchronization signals for cell synchronization. Certain aspects of the present disclosure provide a method for wireless communication. The method generally includes determining a symbol index for transmitting a sequence; determining an amount of cyclical shift in one of a frequency domain and a time domain to apply to the sequence, wherein the amount of cyclical shift in the frequency domain is based on the sequence and the symbol index; shifting the sequence by the amount of cyclical shift; and transmitting the shifted sequence in a symbol corresponding to the symbol index.

The detection and validation of Secondary Synchronization Signal comprising generating a set of samples by performing DFT operation on a time domain LTE signal, wherein the signal comprising an LTE frame divided into an even half and odd half frame, First and second set of hypotheses from even samples in even and odd half frame are generated and third and fourth set of hypotheses from odd samples in even and odd half frame are generated using first and second hypotheses. Even half frame is selected as start of boundary of the frame when location of the peak of first hypotheses is smaller than that of second hypotheses or location of the peak of fourth hypotheses is smaller than that of third hypotheses. The physical layer cell identity is determined from the locations of the peak of the first, second, third and fourth set of hypotheses averaged over multiple frames.

In order to reduce ambiguity in NB-SSS and complexity of receiver processing, a transmitter apparatus generates an SSS, wherein the SSS signal comprises a sequence of OFDM symbols, wherein each symbol of the sequence of SSS symbols is mapped to a codeword symbol of an FEC code. Source symbols of the sequence of SSS symbols carry a PCID and frame timing information, and parity symbols of the sequence of SSS symbols introduce redundancy and coding gain. A receiver receives the NB-SSS over multiple OFDM symbols, each symbol of the SSS comprising a short ZC sequence with a combination of root index and cyclic shift. The apparatus derives path metrics using cross-correlation for each of the plurality of symbols, determines a candidate SSS source message based on the derived path metrics and coding constraints of FEC codewords, and identifies a PCID and timing information based on the candidate SSS source message.

One disclosure of the present specification provides a method for performing measurement based on discovery signals. The method may comprise the steps of: receiving, from cells, discovery signals based on cell-specific reference signals (CRSs); and performing measurement based on the CRS-based discovery signals for a predetermined measurement period. If a measurement bandwidth is six resource blocks (RBs), the predetermined measurement period can be determined by 5*the measurement occasion periodicity of the discovery signals. If the measurement bandwidth is 25 resource blocks (RBs), the predetermined measurement period can be determined by 3*the measurement occasion periodicity of the discovery signals. Also, the discovery signals can be received for a discovery signal occasion duration defined by N consecutive subframes.

In one aspect of the teachings herein, a radio network node advantageously adapts the transmission duration of a synchronization signal with respect to transmission of the synchronization signal in different directions. For example, the radio network node uses a shorter transmission duration in beam directions that are associated with better reception conditions and a longer transmission duration in beam directions that are associated with poorer reception conditions. As a consequence of varying the transmission duration according to received-signal qualities known or expected for the different directions, the radio network node can shorten the overall time needed to complete one synchronization-signal transmission cycle and use less energy, as compared to using a more conservative, longer transmission time in all beam directions.