New Radio is required
Larger spectrum usage to cover all applications
Spectrum
5G-NR main characteristics
Operation from low to very high bands: 0.4 – 100Ghz.
Including standalone operation in unlicensed bands.
Up to 400 MHz component-carrier bandwidth (20 MHz for LTE).
Up to 100MHz in <6GHz.
Up to 400MHz in >6GHz.
Up to 16 component carriers.
Set of different numerologies for optimal operation in different frequency ranges.
Native support for Low Latency.
Shortened Transmission Time Interval (TTI).
Native support for Ultra Reliability (Multiple diversity mechanisms).
Flexible and modular RAN architecture: split fronthaul, split control- and user-plane.
Support for devices connecting directly, with no network (D2D, V2X).
Native end-to-end support for Network Slicing.
New channel coding.
LDPC for data channel, Polar coding for control channel.
Logical ,Transport and Physical Channels Mapping
Logical Channel Definition: Medium Access Control (MAC) Layer of NR provides services to the Radio Link Control (RLC) Layer in the form of logical channels. A logical channel is defined by the type of information it carry and is generally differentiated as a control channel, used for transmission of control and configuration information or as a traffic channel used for the user data.
List of Logical Channels for NR:
Broadcast Control Channel (BCCH): It is used for transmitting system information from the network to UEs in a cell coverage.
Paging Control Channel (PCCH): This is used to page the UEs whose location at cell level is not known to the network.
Common Control Channel (CCCH): It is used for transmission of control information to UEs with respect to Random Access.
Dedicated Traffic Channel (DTCH): It is used for transmission of user data to/from a UE. This is the logical channel type used for transmission of all unicast uplink and downlink user data.
Transport Channel Definition: A transport channel is defined by how and with what characteristics the information is transmitted over the radio interface. From the physical layer, the MAC layer uses services in the form of transport channels. Data on a transport channel are organized into transport blocks.
List of Transport Channels for NR:
Broadcast Channel (BCH): It is used for transmitting the BCCH system information, more specifically Master Information Block (MIB). It has a fixed transport format, provided by the specifications.
Paging Channel (PCH): This channel is used for transmission of paging information from the PCCH logical channel. The PCH supports discontinuous reception (DRX) to allow the device to save battery power by waking up to receive the PCH only at predefined time instants.
Downlink Shared Channel (DL-SCH): This is the main transport channel used for transmitting downlink data in NR. It supports key all NR features such as dynamic rate adaptation and channel aware scheduling, HARQ and spatial multiplexing. DL-SCH is also used for transmitting some parts of the BCCH system info which is not mapped to the BCH. Each device has a DL-SCH per cell it is connected to. In slots where system information is received there is one additional DL-SCH from the device perspective.
Uplink Shared Channel (UL-SCH): This is the uplink counterpart to the DLSCH that is, the uplink transport channel used for transmission of uplink data.
Random-Access Channel (RACH): RACH is also a transport channel, although it does not carry transport blocks.
URLLC: The Ultra Reliability versus Low Latency challenge
RAN decomposition: Distributed RAN (DRAN)
Simplified cell site, allowing densification and reducing costs.
Centralize complex processing and coordination (CoMP).
Enable transportation by packet based technologies (e.g. GPON).
Reduce fronthaul traffic.
Benefit from softwarization.
Be flexible and extendable.
Radio Frame
Radio Access Network (RAN)
Radio Resources Management (RRM).
Control, Dynamic allocation of resources to UEs in both uplink and downlink (scheduling).
Selection of an AMF at UE attachment.
Routing of User Plane data towards UPF(s).
Routing of Control Plane information towards AMF.
Connection setup and release.
Scheduling and transmission of paging messages and system broadcast information.
Measurement and measurement reporting configuration for mobility and scheduling.
Transport level packet marking in the uplink.
Session Management.
Support of Network Slicing.
QoS Flow management and mapping to data radio bearers.
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