Читать книгу Mobile Communications Systems Development - Rajib Taid - Страница 48

A 3GPP protocol layer may perform several important functions and procedures. The functions and procedures performed may be split into several individual technical specifications. For such a protocol layer, it contains an introductory technical specification too, for example, LTE TS 36.201 [89] and 5G NR TS 38.201 [105], which provides an overview and a general description of the concerned protocol layer. The introductory technical specification also describes the detailed relationships among the split technical specifications. It may be also noted that for the same protocol layer, for example, in the case of the UMTS physical layer, there may be separate technical specifications depending on its duplexing modes, i.e. Frequency Division Duplex (FDD) and Time Division Duplex (TDD), of transmission which is used by the physical layer.

However, in the LTE and 5G NR system, no separate technical specification is used to describe the physical layer functions and procedures working in the TDD and FDD mode.