RAN | O-RAN | Open RAN | Open Radio Access Network | Layers |
RAN Elements
- Antennas convert electrical signals into radio waves.
- Radios transform digital information into signals that can be sent wirelessly and ensure that transmissions are in the correct frequency bands with the right power levels.
- Baseband units (BBUs) provide a set of signal processing functions that make wireless communication possible. Traditional baseband uses custom electronics combined with multiple lines of code to enable wireless communication, typically using the licensed radio spectrum. BBU processing detects errors, secures the wireless signal and ensures that wireless resources are used effectively.
RAN Radio Resources
Radio Resources Management Techniques
Power control, scheduling, cell search, cell reselection, handover, radio link or connection monitoring, and connection establishment and re-establishment.
bearer selection (Master Cell Group (MCG), bearer, Secondary Cell Group (SCG) bearer, Split bearer),
Major factors for RAN capabilities
- Channel Bandwidth
- MIMO Antenna Configuration
- Modulation Coding Scheme
- UE radio Condition (SNR/SINR, CQI, RSRP, RSRQ etc.)
- Duplex Mode e.g. FDD, TDD
UE-level Radio Resource/Configuration
- Idle mode DRX
- Connected Mode DRX
- BSR Report period etc
eNodeB Level configurations
- Cell reselection and handover parameters
- Attribute Names ?
- Modifying load calculations and cell priorities
- Attribute Names ?
DU Level Radio Resources
CU Level Radio Resources
RAN KPIs
UEs and eNodeB KPI
- CQI - Channel Quality Indication ex. 1,5 Mhz 10Mhz, 20 Mhz
- CQI, SINR, MCS
- RAN protocol stack status: e.g. PDCP buffer status
- Per user performance statistics such as PDCP throughput, RLC or MAC layer latency, etc
With the KPIs included in the QCI set you can compare user experience and load between different LTE Quality of Service (QoS) Class Indicators (QCI). This helps visualize whether users expecting a high QoS are getting that experience. This also helps you to determine if there is sufficient capacity available to add high value subscribers in the selected location.
- Active UEs DL - Number of active users in downlink per QCI
- Avg User Throughput - Average downlink throughput of users per QCI
- DL PRB Utilization - Percentage of downlink Physical Resource Blocks (PRB) used per QCI
- ERAB Accessibility - Percentage of session setup failures per QCI
- ERAB Retainability - Percentage of sessions with abnormal releases per QCI
- PDCCH CCE Utilization - Percentage of Control Channel Elements (CCE) used per QCI
- PRB Utilization - Physical Resource Block
- Cell reselection and handover parameters; modifying load calculations and cell priorities;
- Carrier/band preferences at per-UE or group of UE granularity.
- intra-RAT and inter-RAT measurement reports, cell quality thresholds, CGI reports and
- measurement gaps on per-UE or per-frequency.
- RSRP - Reference Signal Received Power, -44dbm (good) to -140dbm(bad).
- RSRQ - Reference Signal Received Quality, -19.5dB(bad) to -3dB (good).
- SINR - Signal To Interference Noise Ratio, value should be high
- RB - Resource Block In LTE one Resource Block is about 180 KHz, So 20 MHz has 100 RBs, Less Bandwidth means less Resource Block, More BW means more RBs
- Throughput- In simple terms is transmission symbol/bits per seconds, Or Data transfer rate Up-link (i.e. UE to eNodeB ) or Down-link(eNodeB to UE), the through is directly affected by Bandwidth, Hence Resource Block(because more BW is More RB), affected by Modulation techniques (16QAM,64QAM or FDM), affected by MIMO (Multiple Input Multiple Out Wireless Technique of using multiple antennas at both signal ends to increase the transfer rate)
- Latency,
Cell Level KPI :
- Cell load statistics such as information in the form of
- number of active users or connections,
- number of scheduled,
- active users per TTI,
- PRB utilization, and
- CCE utilization.
- Maximum number of users
References
https://www.youtube.com/watch?v=mHvV_Tv8HDQ
https://www.techtarget.com/searchnetworking/definition/modulation
Physics
Amplitude Modulation
64 QAM [ Quadrative Amplitude modulation ] = 6 bits/Hz
16 QAM [ ] = 4 bits/Hz
Frequency Modulation
Phase Modulation
QPSK [Quadrature Phase Shift Keying] = 2 bits/Hz
RRC_IDLE State : UE Controlled
RRC_CONNECTED : E-UTRAN(eNodeB) controlled
AMF to UE
Commands
The AMF should not request acknowledgement of the NITZ command. The AMF shall request acknowledgement for NSSAI information (e.g. Allowed NSSAI), 5G-GUTI, TAI List and Mobility Restrictions, LADN Information, MICO, Operator-defined access category definitions, PLMN-assigned UE Radio Capability ID and SMS subscription
https://www.tech-invite.com/3m23/img/tinv-23-502-4.2.4.2-1.gif
Control Plane and User Plane
- MIB (master Info Block)
- System Info Block
- Carry signals
- System BW,
- PHICH Conf,
- Frame number,
- Nu of antenna,
- 4 Bits
- Handover,
- Initial,
- attachment,
- Cell selection,
- Track area code,
- SIB2(RRC Info common for all UE.
- Page Info,
- PUCCH,PUSCH)
- Info of same cell
- Performance measurements,
- MDT reports, RLF reports,
- RCEF reports,
- UE location reports,
- together with the geographical, terrain and configuration data of the RAN
- Failure of random access,
- Paging, RRC connection establishment or handover,
- Low data throughput,
- Abnormal releases of RRC connection or UE context,
- Dissatisfied QoE
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