Showing posts with label 5G. Show all posts
Showing posts with label 5G. Show all posts

MOM of gNodeB




GnodeBFunction. (This MO is the top level MO for GNodeB Functions.)
GnodeBRpFunction (Radio Processing)
  QciProfileEndcConfig Route from QCIs to parameters that impacts QoS for Data Radio Bearers.

  Radio Bearer is just a virtual concept. It defines how the UE data/signaling are treated when it travels across the network.
  Ej. In LTE there are two types of radio Bearer To carry signaling. There are called the SRB (Signaling Radio Bearer)
  To carry user data. There are associated with an EPS Bearer
  RadioBearertable: Container for radio bearer configurations.
  User plane link for the radio processing interface.
 
System created when a radio processing user plane link is established.
 
System deleted when a radio processing user plane link is released.
 
RDN of this MO is RpUserPlaneLink=[Local Ip Address]_[Remote Ip Address]. 
  RpUserPlaneTermination Local termination point of the radio processing user plane interface.
  TddRadioChannel Represents frequency and bandwidth over a time division duplex radio channel.
PpFunction (Packet Processing)
  Traffic processing interface.

NSA-ENDC Interfaces






It ‘s possible to transmit the user plane between both nodes to the EPC but control plane is only possible on the ENDC side.
GTP (GPRS Tunneling Protocol) . S1 user plane is tunneled between the LTE node and SGW using GTP-U
UDP (User Datagram Protocol)
S1AP (S1 Application Protocol)
SCTP (Stream Control Transmission Protocol)

5G Architecture












In option 3 there are 3 deployment scenarios for NSA NR they consist of at least two nodes, one for LTE and one for NR.
LTE-NR Dual Connectivity feature 
-The LTE-NR Dual Connectivity feature introduces the support for EN-DC in the NR Node used in an NSA deployment.
-The feature covers the fundamental interaction between LTE and NR in the EN-DC context.
-The feature makes it possible to configure split DRBs with one leg in LTE and one leg in NR.
 
The benefits of this setup are the following:
  Higher peak rate of network data traffic.
  Sustainable capacity and performance growth.

-CONTROL PLANE
  Master Cell Group (MCG) SRB (SRB1, SRB2): SRB (Signal Radio Bearer)
  Direct SRB between the master node and the mobile device that can be used for conveying master node RRC messages which can also embed secondary node RRC configurations.
  Split SRB (SRB1+SRB1S, SRB2+SRB2S): 
  SRB that is split between the master node and the secondary node (at a higher layer, PDCP) towards the mobile device, allowing a master node RRC message to be sent via the lower layers (RLC, MAC and PHY) of either the   master node or secondary node; or to be sent via the lower layers of both the master and secondary nodes. Here, the master node RRC message can also embed secondary node RRC configurations.
  Secondary Cell Group (SCG) SRB (SRB3): 
  Direct SRB between the secondary node and the mobile device by which secondary node RRC messages are sent.
-USER PLANE
  MCG DRBs: DRB (Data Radio Bearer)
  Bearers terminated at the master node and using only the master node lower layers.
  MCG split DRBs:
  Bearers terminated at the master node but that can use the lower layers of either the master node or secondary node; or can use the lower  layers of both the master and secondary nodes.
  SCG DRBs:
  Bearers terminated at the SN and using only the secondary node lower layers.
An additional data radio bearer has been introduced in EN-DC:
  SCG split DRBs:
  Bearers terminated at the secondary node but that can use the lower layers of either the master node or secondary node, or can use the lower   layers of both the master and secondary nodes.
Adopting current LTE DC procedures for the introduction of the SCG split DRB entails that every bearer type change will require a re-establishment in the PDCP layer, as well as in some cases signaling towards the core network to switch the path from the core network to the radio access network. To minimize the impact of such bearer type changes, and minimize implementation and testing efforts on mobile devices, 3GPP has agreed to harmonize the bearer definitions. With the harmonized bearer concept, there will be only two kinds of bearers from the mobile device perspective:
  Direct DRBs: 
  DRBs with only one lower layer configuration, either corresponding to LTE or NR lower layers. If the LTE lower layers are configured, either the   NR or the LTE version of the higher layer can be used by the bearer. If the NR lower layers are configured, the NR version of the higher layer will   be used.
  Split DRBs: 
  DRBs with two lower layer configurations, corresponding to LTE and NR lower layers. It will always use the NR version of the higher layer. In case   of split DRBs, packet duplication, when it is finalized as a new functionality in Release 15, could be used for additional reliability.
Limitations.
It is not recommended for EN-DC UEs to use VoLTE due to the lack of support for important VoLTE related features.
The VoLTE performance is expected to be poor due to the following:
  TTI (Transmission Time Interval) Bundling cannot be used.
  Handover support is limited.
  RRC re-establishment for EN-DC UEs is not supported.

Sparse Code Multiple Access - SCMA



Sparse code multiple access (SCMA) is another waveform configuration of the flexible new air interface. This non-orthogonal waveform facilitates a new multiple access scheme in which sparse codewords of multiple layers of devices are overlaid in code and power domains and carried over shared time-frequency resources. Typically, the multiplexing of multiple devices may become overloaded if the number of overlaid layers is more than the length of the multiplexed codewords.
However, with SCMA, overloading is tolerable with moderate complexity of detection thanks to the reduced size of the SCMA multi-dimensional constellation and the sparseness of SCMA codewords. In SCMA, coded bits are directly mapped to multi-dimensional sparse codewords selected from layer-specific SCMA codebooks. The complexity of detection is controlled through two major factors. One is the sparseness level of codewords, and the second is the use of multidimensional constellations with a low number of projection points per dimension [3]. An example of device multiplexing with a low projection codebook and the resulting constellation mapping is shown Figure   A device’s encoded bits are first mapped to a codeword from a codebook. In the example, a codeword of length 4 is used. The low projection codebook has a reduced constellation (from 4 points to 3 points). Furthermore, each point (e.g. “00”) has non-zero component only in one tone. A codebook with one non-zero component is a zero-PAPR codebook.


                                        SCMA multiplexing and low projection codebook constellation

Furthermore, a blind multi-device reception technique can be applied to detect device activities and the information carried by them simultaneously. With such blind detection capability, grant-free multiple access can be supported. Grant-free multiple access is a mechanism that eliminates the dynamic request and grant signaling overhead. It is an attractive solution for small packets transmission. SCMA is an enabler for grant-free multiple access. Due to these benefits,SCMA can support massive connectivity, reduce transmission latency and provide energy saving.

5G Spectrum



The growing traffic demand necessitates increasing the amount of spectrum that may be utilised by the
5G systems. High frequency bands in the centimeter wave (cmWave) and millimeter wave (mmWave)
range will be adopted due to their potential for supporting wider channel bandwidths and the consequent
capability to deliver high data rates.
The new spectrum below 6GHz is expected to be allocated for mobile communication at the World Radio
Conference (WRC) 2015, and the band above 6GHz expected to be allocated at WRC 2019, as shown in
Figure.




5G network is a heterogeneous network which enables the cooperation between lower-frequency wide-area coverage network and high-frequency network. The consensus is higher frequency bands are the complementary bands to 5G whereas low frequency bands (<6GHz) are still the primary bands of 5G spectrum.

High frequency also enables unified access and backhaul since the same radio resources is shared. It is expected to use a unified air interface and a hierarchical scheduling for both radio access and backhaul which enables flexible backhauling and low-cost ultra dense networking (UDN).

Future radio access may also employ bands with different levels of access regulation including exclusive licensed, non-exclusive licensed and unlicensed bands. The 5G system treats both the licensed and unlicensed spectrum in a flexible, unified air interface framework.