2 Interfaces to the physical layer

04.043GPPLayer 1 - General RequirementsRelease 1999TS

The physical layer (layer 1) is the lowest layer in the OSI Reference Model and it supports all functions required for the transmission of bit streams on the physical medium. These bit streams are transferred on traffic channels, packet data traffic channels and control channels as defined in 3GPP TS 04.03.

NOTE: For GSM application the physical layer may also be referred to as the radio subsystem. However, the radio subsystem supports functions additional to those described in the present document.

The physical layer interfaces the Data Link Layer, the Radio Link Control and Medium Access Control layer and the supported functional units of the application (figure 2.1).

Figure 2.1: Interfaces with the Physical Layer

2.1 Interface to the Data Link Layer

The physical layer interfaces the data link layer. On this interface control channels are supported. The data link layer is specified in 3GPP TS 04.05 and 3GPP TS 04.06. Communication between the Physical Layer and the Data Link Layer is in an abstract way performed by means of PH‑primitives. They do not constrain implementations.

NOTE: The terms physical layer and layer 1, and data link layer and layer 2, will be used synonymously in the present document.

The PH‑primitives exchanged between the physical layer and the data link layer are used for the transfer of layer 2 frames. They are also used to indicate the establishment of channels to layer 2.

2.1a Interface to the Radio Link Control and Medium Access Control layer

The physical layer interfaces the Radio Link Control and Medium Access Control (RLC/MAC) layer. On this interface packet data control channels and packet data traffic channels are supported. The RLC/MAC layer is specified in 3GPP TS 04.60. Communication between the Physical Layer and the RLC/MAC layer is in an abstract way performed by means of PH‑primitives. They do not constrain implementations.

The PH‑primitives exchanged between the physical layer and the RLC/MAC layer are used for the transfer of RLC/MAC blocks. They are also used to indicate the establishment of packet data physical channels to the RLC/MAC layer.

2.2 Interface to radio resource management

The physical layer interfaces the radio resource management (RR‑management) entity of layer 3 in the MS and in the network.

Communication is performed in an abstract way by means of MPH‑primitives. They do not constrain implementations.

The primitives exchanged with the RR‑management entity are related to the assignment of channels, physical layer system information (including measurement results), etc.

2.3 Interface to other functional units

The physical layer interfaces other functional units in the MS and in the network for supporting traffic channels. These interfaces are described in the 06 and 07 series of 3GPP Technical Specifications.