5G-NR: Channels
Introduction:
In this blog, we will discuss all types of changes, their functionality, and channel mapping in short. Like LTE, NR channels are the same.
Mainly there are three types of channels :
1- Logical channels
2- Transport channels
3- Physical channels
1- Logical Channels:
1- Logical Channels:
Logical channels are functioning between RLC and MAC layers. There are 5 types of logical channels. Logical channels are further divided into two groups, Fist is control channels and second is traffic channels. below are the logical channels and their short description.
1- BCCH (Broadcast control channels)
2- PCCH (Paging control channels)
3- CCCH (Common control channels)
4- DCCH (Dedicated control channels)
5- DTCH (Dedicated traffic channels) => Traffic channel
1- BCCH (Broadcast control channels):
The network always transmits the BCCH over the air in the downlink. This is downlink broad channels.(gNB --> UEs). it is used to transmit the system information messages like SIBs and MIB in the downlink.
=> In 5G NSA(non-standalone mode), system information is not transmitted over BCCH channels. it is transmitted via master note i.s. LTE eNodeB.
=> in 5g SA(Standalone mode), system information(MIB and SIBs) transmitted through the BCCH channel.
=> In 5G NSA(non-standalone mode), system information is not transmitted over BCCH channels. it is transmitted via master note i.s. LTE eNodeB.
=> in 5g SA(Standalone mode), system information(MIB and SIBs) transmitted through the BCCH channel.
2- PCCH (Paging control channels):
PCCH is also a downlink channel and it is used for transmitting paging information from the network to devices. whenever the network needs to find out the devices, then the network uses the PCCH channel for paging information.
It can also be used to transmit the system information change notification and an indication of ongoing PWS (public warning system) broadcast.
=> In 5G NSA(non-standalone mode): paging is not transmitted over PCCH channels. it is transmitted via master note i.s. LTE eNodeB.
=> in 5g SA(Standalone mode), paging transmitted through the PCCH channel.
=> In 5G NSA(non-standalone mode): paging is not transmitted over PCCH channels. it is transmitted via master note i.s. LTE eNodeB.
=> in 5g SA(Standalone mode), paging transmitted through the PCCH channel.
3- CCCH (Common control channels):
CCCH is used by a device to establish or re-establish an RRC(radio resource control) connection. this is referred to as SRB(Signaling radio bearer) 0.
4- DCCH (Dedicated control channels):
This is a two-way channel for the transfer of control information when the device has an RRC connection. SRBs when DCCH is activated including
SRB -1: This is used for RRC message
SRB -2: This is used for NAS(non-access stratum) messages and has a lower priority than SRB -1.
SRB -3: This is newly introduced in 5G NSA(non-standalone mode ). this is used to configure measurements, MAC, RLC, physical layer parameters as well as RLF(radio link failure) parameters.
5- DTCH (Dedicated traffic channels):
This is a point to point channel that may exist in the uplink and downlink. It is a part of DRB(Data radio Bearer) assigned to the devices. this channel is mainely used for transfring the userdata
2-Transport channel:
Transport channels are functioning between MAC layer and Physical layer. there are 5 types of Transport channels.
1- BCH (Broadcast channel)
This is a broadcast channel that is a part of the SS(Synchronization signal) block. it includes the MIB.
2- DL-SCH (Downlink chared channel)
2- DL-SCH (Downlink chared channel)
This channel supports dynamic scheduling and dynamic link adaptation by varying the antenna mapping, modulation, coding scheme, and resources/power allocation. In addition, it supports HARQ (Hybrid automatic repeat request) operation to improve performance.
3- PCH (Paging Channel)
3- PCH (Paging Channel)
This channel is used to carry the PCCH, It utilizes DRX(discontinuous reception) to improve the battery life.
4- UL-SCH (Uplink shared channel)
4- UL-SCH (Uplink shared channel)
This is similar to DL-SCH, it used for uplink data transmission. It also supports the DRX algorithems for device power saving.
5- RACH (Random access channel)
This channel carries limited information and is used in configuration with physical channel and preamble to improve contention resolution procedure.
This channel is also defined in the transport channels, although it does not carry transport block.
3- Physical Channels:
Physical channels are used to transmit the signals on the air. There are 6 types of Physical channels. in which three channels are downlink channels and the other three channels are uplink channels.
5- RACH (Random access channel)
This channel carries limited information and is used in configuration with physical channel and preamble to improve contention resolution procedure.
This channel is also defined in the transport channels, although it does not carry transport block.
3- Physical Channels:
Physical channels are used to transmit the signals on the air. There are 6 types of Physical channels. in which three channels are downlink channels and the other three channels are uplink channels.
1-PBCH (Physical broadcast channel)
2-PD-SCH (Physical downlink shared channel)
3-PDCCH (Physical downlink control channel)
4-PRACH (Physical Random access channel)
5-PU-SCH (Physical uplink shared channel)
6-PUCCH (Physical uplink control channel)
1-PBCH(Physical broadcast channel)
The network always transmits the BCCH over the air in the downlink. This is downlink broad channels.(gNB --> UEs). it is used to transmit the system information messages like SIBs and MIB in the downlink.
=> In 5G NSA(non-standalone mode), system information is not transmitted over BCCH channels. it is transmitted via master note i.s. LTE eNodeB.
=> in 5g SA(Standalone mode), system information(MIB and SIBs) transmitted through the BCCH channel.
The network always transmits the BCCH over the air in the downlink. This is downlink broad channels.(gNB --> UEs). it is used to transmit the system information messages like SIBs and MIB in the downlink.
=> In 5G NSA(non-standalone mode), system information is not transmitted over BCCH channels. it is transmitted via master note i.s. LTE eNodeB.
=> in 5g SA(Standalone mode), system information(MIB and SIBs) transmitted through the BCCH channel.
2-PD-SCH(Physical downlink shared channel)
This channel supports dynamic scheduling and dynamic link adaptation by varying the antenna mapping, modulation, coding scheme, and resources/power allocation. In addition, it supports HARQ (Hybrid automatic repeat request) operation to improve performance.
it is also used for--
- Unicast data transmission
- Random access responce message
- delevery part of System information messages
This channel supports dynamic scheduling and dynamic link adaptation by varying the antenna mapping, modulation, coding scheme, and resources/power allocation. In addition, it supports HARQ (Hybrid automatic repeat request) operation to improve performance.
it is also used for--
- Unicast data transmission
- Random access responce message
- delevery part of System information messages
3-PDCCH(Physical downlink control channel)
This channel is used for downlink control information(DCI). downlink control information is necessary for proper reception and decoding of downlink user data.
This channel is used for downlink control information(DCI). downlink control information is necessary for proper reception and decoding of downlink user data.
4-PRACH(Physical Random access channel)
This channel carries limited information and is used in configuration with physical channel and preamble to improve contention resolution procedure.
This channel is also defined in the transport channels, although it does not carry transport block.
This channel carries limited information and is used in configuration with physical channel and preamble to improve contention resolution procedure.
This channel is also defined in the transport channels, although it does not carry transport block.
5-PU-SCH(Physical uplink shared channel)
This is similar to DL-SCH, it used for uplink data transmission. It also supports the DRX algorithms for device power saving.
This is similar to DL-SCH, it used for uplink data transmission. It also supports the DRX algorithms for device power saving.
6-PUCCH(Physical uplink control channel)
This channel is used for uplink control information(DCI). uplink control information is necessary for scheduling and HARQ procedure.
Channel Mapping:
This channel is used for uplink control information(DCI). uplink control information is necessary for scheduling and HARQ procedure.
Channel Mapping:
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