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. The apparatus may also determine a PUSCH format of a group of PUSCH formats for allocating at least one RU to a UE for a NPUCCH. In addition, the apparatus may allocate the at least one RU to the UE using the determined PUSCH format. In one aspect, the RU may include one or more subcarriers in each of one or more slots.