The disclosure relates to a method performed by a UE, for using subframes of a radio access network for a D2D communication. The method comprises determining (650) subframes available for D2D communication among subframes of the radio access network. The subframes available for D2D communication exclude a number of subframes of the radio access network, such that a periodicity of the D2D communication in number of subframes divides the number of subframes available for D2D communication. The method also comprises using (660) the determined subframes for enabling D2D communication.

There is a need to support narrowband TDD frame structure for narrowband communications. The present disclosure provides a solution by supporting one or more narrowband TDD frame structure(s) for narrowband communications. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may determine a bandwidth for narrowband communications. The apparatus may determine a narrowband TDD frame structure for the narrowband communications. In one aspect, the narrowband TDD frame structure may include at least one of two or more contiguous downlink subframes, or one or more flexible subframes that can be configured as either a downlink subframe or an uplink subframe. The apparatus may communicate with a UE using the narrowband TDD frame structure determined for the narrowband communications.

There is a need to support narrowband TDD frame structure for narrowband communications. The present disclosure provides a solution by supporting one or more narrowband TDD frame structure(s) for narrowband communications. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may determine a TDD mode for narrowband communications. The apparatus may determine a TDD frame structure for the narrowband communications from a group of narrowband TDD frame structures. In one aspect, at least one common subframe in each narrowband TDD frame structure in the group of narrowband TDD frame structures may be configured as a downlink subframe. The apparatus may transmit a PSS using the at least one common subframe in the narrowband TDD frame structure determined for the narrowband communications.

There is a need to support narrowband TDD frame structure for narrowband communications. The present disclosure provides a solution by supporting one or more narrowband TDD frame structure(s) for narrowband communications. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may determine a narrowband communication frame structure comprising a FDD mode or a TDD mode and a particular TDD frame structure for narrowband communications from a group of narrowband TDD frame structures. The apparatus may determine a periodicity, subframe number, and transmission sequence associated with a SSS based at least in part on the narrowband TDD frame structure. The apparatus may transmit the SSS using the narrowband TDD frame structure determined for the narrowband communications. In one aspect, the SSS may be transmitted in a same subframe within a frame and at a periodicity of 2 or more frames

There is a need to support narrowband TDD frame structure for narrowband communications. The present disclosure provides a solution by supporting one or more narrowband TDD frame structure(s) for narrowband communications. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may determine a narrowband TDD frame structure for narrowband communications from a group of narrowband TDD frame structures. In one aspect, the narrowband TDD frame structure may include a set of downlink subframes and more than one special subframe. The apparatus may determine a set of narrowband carriers and a minimum set of subframes on the set of narrowband carriers based at least in part on the set of downlink subframes and more than one special subframe on which a NRS should be transmitted. The apparatus may transmit the NRS using the narrowband TDD frame structure determined for the narrowband communications.

There is a need to support narrowband TDD frame structure for narrowband communications. The present disclosure provides a solution by supporting one or more narrowband TDD frame structure(s) for narrowband communications. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may determine a narrowband communication frame structure comprising a FDD frame structure or a TDD frame structure and a narrowband TDD frame structure configuration for narrowband communications from a group of narrowband TDD frame structures configurations. The apparatus may determine one or more narrowband carriers and subframes within the one or more narrowband carriers to transmit at least one of a BCH or a SIB1 based on the narrowband communication frame structure or the TDD frame structure configuration. The apparatus may transmit a PSS, an SSS, and at least one of a BCH or an SIB1 using the narrowband TDD frame structure determined for the narrowband communications. In one aspect, a carrier used for transmitting the BCH and/or the SIB may be different than a carrier used to transmit one or more of the PSS or the SSS. In another aspect, a narrowband carrier used for transmitting the BCH may be different than a narrowband carrier used to transmit one or more of the PSS or the SSS.

A method determining a timing of an uplink signal includes receiving timing information associated with an uplink signal and a numerology of the uplink signal, wherein the timing information is used to determine a reference time of the uplink signal received from a user equipment (UE), receiving, from the UE, the uplink signal, wherein the receiving is in accordance with the timing information and the numerology of the uplink signal, and measuring an uplink relative time of arrival in accordance with the received uplink signal and the reference time of the uplink signal.

A method determining a timing of an uplink signal includes receiving timing information associated with an uplink signal and a numerology of the uplink signal, wherein the timing information is used to determine a reference time of the uplink signal received from a user equipment (UE), receiving, from the UE, the uplink signal, wherein the receiving is in accordance with the timing information and the numerology of the uplink signal, and measuring an uplink relative time of arrival in accordance with the received uplink signal and the reference time of the uplink signal.