Logical channels are used to carry different types of data, such as control data, user data, and signaling data. There are two types of logical channels in 5G NR: control channels and traffic channels.
Control channels are used to carry control information, such as signaling messages. Signaling messages are used to manage the radio interface between the user equipment (UE) and the base station (BS). For example, signaling messages are used to establish a connection, to send data, and to release a connection.
Traffic channels are used to carry user data, such as web pages, videos, and audio. Traffic channels are used to transmit data between the UE and the gNB.
The logical channels reside between the RLC (Radio Link Control) and MAC (Medium Access Control) layers in the 5G NR protocol stack.
These channels play a crucial role in determining the nature of data that can be transmitted.
On the other hand, the transport channels are responsible for carrying information from the MAC layer to the PHY (Physical) layer. They not only specify the method by which the information is transported to the physical layer but also define the specific characteristics of the data.
Finally, the physical layer establishes direct communication with the user equipment through the physical channels. These channels encompass various aspects such as timing, access protocols, and data rates, which are essential for establishing a reliable and efficient connection
to get an idea, Imagine you are sending multiple types of information, such as letters, photos, and documents, to your friend through a postal service. Each type of information represents different logical channels. You carefully categorize and label each piece of information based on its content, ensuring efficient handling and delivery. For example, you place letters in envelopes, attach specific labels or tags to photos, and organize documents into folders. Each labeled category represents a logical channel, enabling the postal service to process and route the information effectively.