US Patent 10454659 Narrowband time-division duplex frame structure for 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 receive information associated with a narrowband TDD frame structure for narrowband communications. The apparatus may transmit a first symbol group of a first narrowband physical random access channel (NPRACH) preamble to a base station. In one aspect, a first length of the first symbol group may be associated with the narrowband TDD frame structure.