5G Channel Types | 5G Logical Channels, 5G Transport Channels
This page covers 5G channel types viz. logical channels and transport channels used in uplink and downlink with mapping between them. The 5G logical channels include xBCCH, xCCCH, xDCCH, xDTCH etc. The 5G transport channels include xBCH, xDL-SCH, xRACH, xUL-SCH etc.
These 5G channels are used to provide different kinds of data transfer services by MAC layer in 5G protocol stack.
5G Logical Channels | xBCCH, xCCCH, xDCCH, xDTCH
The 5G logical channels are further divided into control channels and traffic channels based on their functionalities. They are described below.
Each of the 5G logical channels are defined by what information type is transferred by them.
Logical channels are classified into two groups as follows.
• Control channel: It is used to transfer control plane related information.
• Traffic channel: It is used to transfer user plane related information.
5G Control Channels
Following table-1 mentions 5G control channels used to transfer control plane information only. The control channels offered by 5G-MAC are xBCCH, xCCCH and xDCCH.
|5G control channel type||Description|
|xBCCH||This channel is used in the downlink to broadcast system control information.|
|xCCCH||This channel is used to transmit control information between UEs and network (i.e. 5G-Node B or base station). It is used for UEs having no RRC connection with network.|
|xDCCH||This channel is bi-directional and point to point. It carries dedicated control information between UE and network. It is used by UEs having RRC connection.|
5G traffic channel | xDTCH
• The 5G traffic channel is used to transfer user plane information only.
• The xDTCH is the only dedicated traffic channel used in 5G wireless technology.
• It is a point to point channel which is dedicated to single UE.
• It carries user information.
• It exists both in the downlink (From 5G-NB to UE) and uplink (From UE to 5G-NB).
Mapping between Logical Channels and Transport Channels
The figure depicts mapping between logical channels and transport channels in the uplink and downlink.
As shown following are the mapping in uplink side.
• xCCCH channel can be mapped to channel xUL-SCH
• xDCCH channel can be mapped to channel xUL-SCH
• xDTCH channel can be mapped to channel xUL-SCH
As shown following are the mapping in downlink side.
• xBCCH channel can be mapped to channel xBCH
• xCCCH channel can be mapped to channel xDL-SCH
• xDCCH channel can be mapped to channel xDL-SCH
• xDTCH channel can be mapped to channel xDL-SCH
5G Transport Channels | xBCH, xDL-SCH, xRACH, xUL-SCH
The 5G transport channels are used by 5G physical layer (i.e. layer-1) based on their functionalities. They are described below.
|5G transport channel type||Description|
|xBCH||It is 5G broadcast channel which carries system control information of 5G MAC layer.|
|xDL-SCH||It is 5G Downlink Shared Channel which carries data of all the UEs in the downlink direction from 5G Base station.|
|xUL-SCH||It is 5G Uplink Shared Channel which carries data from UEs to 5G base station in the uplink direction.|
|xRACH||It is 5G Random Access Channel which is used by UE in the uplink direction to establish connection with 5G base station. It is used to establish 5G-RRC Connection between UE and 5G-RAN in RRC connection setup procedure.|
5G NR Numerology | 5G NR Terminology
5G NR Control channels | 5G NR Traffic Channels | 5G NR Reference Signals and sequences
5G TECHNOLOGY RELATED LINKS
This 5G tutorial also covers following sub topics on the 5G technology:
5G basic tutorial
5G Frequency Bands
5G millimeter wave tutorial
5G mm wave frame
5G millimeter wave channel sounding
Difference between 4G and 5G
5G testing and test equipments
5G network architecture
5G NR Physical layer
5G NR MAC layer
5G NR RLC layer
5G NR PDCP layer