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5 g ran_jnn_atal_fdp
- 1. 16-07-2021 1 5G RAN (NG-RAN) E-mail:info@nanocellnetworks.com 5G RAN NG-RAN Overview NR Overview Protocol Architecture- RAN RAN Deployment Options
- 2. 16-07-2021 2 5G targets 5G targets Peak(Theoreticalmaximum) data rate; DL/UL SE: 30/15 bps/Hz EPC Control plane latency of 10ms User plane latency of 0.5ms for uplink and the same for downlink for URLLC cases. User plane latency of 4ms for uplink and the same for downlink for eMBB cases. Mobility interruption time should be 0ms 5G targets(Contd) 5G targets(Contd) Maximum cell range without KPI degradation should be 100km. Target battery life for mMTC (IoT) devices of 15 years Maximum connection density of 1 million devices per square kilometre. Support for connecting to a user travelling at a maximum speed of 500km/h.
- 3. 16-07-2021 3 5G RAN Approach 5GRAN Approach LTE NR Rel. 15 Phase 1 RAN specifications to address only eMBB with advancements towards the low-latency part of URLLC Only NSA approach in phase 1, i.e., always with LTE as the anchor Rel. 15 Phase 2 RAN specifications to address standalone 5G NR operations including coverage of the robustness part for URLLC 5G is evolving and many features will come in future releases to complete the 5G picture 5G NG-RAN requirements 5G NG-RAN requirements LTE NR EPC 5G Core Deployment flexibility (e.g. to host relevant RAN, Core Network (CN) and application functions close together at the edges of the network, when needed Allow deployments using Network Function Virtualization RAN-CN interfaces and RAN internal interfaces shall be open for multi-vendor interoperability Support Sharing of RAN between multiple operators
- 4. 16-07-2021 4 5G NR requirements 5GNR requirements LTE NR Tight interworking between the New Radio and LTE At least dual connectivity between LTE and new RAT, to support high performing inter-RAT mobility and aggregation of data flows Multiple transmission points, either collocated or non-collocated Separation of control plane signaling and user plane data from different sites (C-plane/U-plane separation) Inter-site scheduling coordination Different options and flexibility for splitting the RAN architecture 5G NR - Introduction OFDMA on DL & UL Flexible numerology- SCFDMA possible on UL Same SF/Frame/slot durations Allocation can happen at granularity of OFDM symbol; aggregation of slots also possible Same PRB structure No change from 12 REs in frequency axis CA & DC support Continued.. maximum up to 16 CA as of now Flexible TDD along with FDD Old methods allowed along with new Modulation Up-to 256 QAM Coding LDPC & Polar codes
- 5. 16-07-2021 5 5G NR -Introduction Parameters FR1 (450MHz- 7.125MHz) FR2 (24250MHz-52600MHz) OFDM Parameterization In LTE OFDM Parameterization In LTE Constraints • Tcp>Td Cyclic Prefix • Tcp<<Tos Subcarrier spacing • ∆f>>fDmax LTE design involved these tradeoffs Sampling frequency, frame time all have backward compatibility in mind Delay spread Cyclic Prefix OFDM Symbol Period Subcarrier spacing Doppler Spread
- 6. 16-07-2021 6 Flexible OFDM for5G Flexible OFDM for 5G Subcarrier spacing (Flexible) = f0* 2µ, f0=15 kHz, µ=-2,…5 3.75k (15K) ≤∆f< (240)480 kHz BWs: Min: 5 MHz for f<6GHz Min 50 MHz for f>6GHz Max. 400 MHz in R 15 IoT cases Used in mm wave for higher phase noise; manageable subcarrier spacings Why is this flexibility in OFDM parameters needed for 5G? Different Numerology to suit different bandwidths/applications; Combo. of subcarrier spacing and CP durations Why large subcarrier spacings for mm-wave? Why large subcarrier spacings for mm-wave? Potential use of high frequencies; 26-28 GHz, 39 GHz,and beyond Absolute values of frequency offsets and phase noise related parameters are higher than in lower frequencies OFDM signals are affected relative to subcarrier spacing..in freq. domain.. If the same subcarrier spacing as LTE is used, then effects are amplified Large bandwidths are the big plus in mm-wave; low subcarrier spacings means large FFT sizes; which implies high complexity
- 7. 16-07-2021 7 OFDM usage for5G – Frequency View of Potential Waveform OFDM usage for 5G – Frequency View of Potential Waveform Frequency Wideband (e.g. eMBB) Narrowband (e.g. IoT) Large CP (e.g.Broadcast) • High frequency • Manageable FFT size with large BW • Sub 1GHz • Longer range Mix of services achieved through different subcarrier spacings; minimal wastage of guard band OFDM Parameter Possibilities for Rel 15 5G OFDM Parameter Possibilities for Rel 15 5G Less than 15 KHz subcarrier spacing can be handy for IOT and multicast.. Planned for later releases Max. CC bandwidth specified is 400 MHz so far with max. FFT size of 4096 Max. CCs for signalling purpose is 16 Source: Keysight
- 8. 16-07-2021 8 OFDM usage for5G – Time-Frequency View of Potential Waveform OFDM usage for 5G – Time-Frequency View of Potential Waveform Different time and frequency parameters for different services; OFDM symbol time, CP, subcarrier spacing Filtering to take care of time and frequency misalignments All numerologies to align @ subframe boundary which occurs every 1 ms; i.e. OFDM symbol for all numerologies should have a starting point @ the subframe starting point Plan for even 1 or 2 OFDM symbol transmissions; low latency, unlicensed band use cases OFDM Numerology – Example; 10 MHz Bandwidth OFDM Numerology – Example; 10 MHz Bandwidth • 15 KHz, µ=0 • Useful OFDM symbol time = 1/15K ~= 66.67 µs • Normal Cyclic prefix ~= 4.6 µs • Max. FFT size = 1024 • Same cyclic prefix as LTE • Number Sub Carriers = 600 • 30 KHz, µ=1 • Useful OFDM symbol time = 1/30K ~= 33.33 µs • Normal Cyclic prefix ~= 2.3 µs • Max. FFT size =512 • Half of LTE CP • Number of Sub Carriers = 300
- 9. 16-07-2021 9 OFDM Numerology invisual form OFDM Numerology in visual form Alignment of OFDM symbol boundaries at 1 ms Except for the first OFDM symbol, the rest have the same length This example has considered a 4096 FFT in different bandwidths OFDM Numerology – Numerology points OFDM Numerology – Numerology points • µ gives the subcarrier spacing used; useful OFDM symbol time and cyclic prefix fixed (option to have extended CP in some cases) • FFT size depends on the bandwidth; sampling rate for calculation is fixed with bandwidth; max. FFT sizes and bandwidths are specified in the standard • Same bandwidth can have different subcarrier spacings; OFDM symbol duration and CP duration are different; implications for handling delay spread • Integer relationships between the OFDM symbol periods of different numerologies; easier coexistence even in the same time interval • Multiple numerologies give choices for handling different application; Different parts of a larger channel bandwidth could have different numerologies
- 10. 16-07-2021 10 5G NR- Betterspectral utilization than LTE 5G NR- Better spectral utilization than LTE Source : Nokia 5G PRBs and different numerology 5G PRBs and different numerology # of PRBs in a given bandwidth depends on the numerology chosen • 15 KHz -16 PRBs • 30 KHz – 8 PRBs • 60 KHz – 4 PRBs • 120 KHz- 2 PRBs gNB can mix numerologies in a DL transmission and schedule in an UL transmission
- 11. 16-07-2021 11 5G NR FrameStructure 5G NR Frame Structure Slot is the more important time unit from a scheduling perspective; smaller slots useful for handling low latency applications Source: 5G Book 5G NR Frame Structure 5G NR Frame Structure Source: Keysight Same frame structure irrespective of FDD or TDD or unlicensed operation
- 12. 16-07-2021 12 5G Numerology Implicationson various parameters 5G Numerology Implications on various parameters UE is not expected to be able to receive in different numerologies at the same time in R 15 gNB can use different numerologies to different users in the same slot Inter user interference due to different numerologies has to be taken care of 5G NR Flexibility ..in numbers 5G NR Flexibility ..in numbers http://niviuk.free.fr/store_nr.php
- 13. 16-07-2021 13 5G RAN RAN ProtocolArchitecture 5G RAN – Control Plane 5G RAN – Control Plane N11 Stack NAS SM = 5GSM NAS MM = 5GMM
- 14. 16-07-2021 14 gNodeB – N1/N2Interface gNodeB – N1/N2 Interface Source: GL Communications gNodeB – User Plane gNodeB – User Plane
- 15. 16-07-2021 15 • NR PDCP,RLC and MAC are all new protocols but share many similarities with corresponding LTE protocols • SDAP (Service Data Application Protocol) is introduced to support new flow based QoS model of the 5GC gNB PHY UE PHY MAC RLC MAC PDCP PDCP RLC SDAP SDAP User Plane Data Handling User Plane Data Handling QoS Flow based markings at the core network; no concept of EPS bearer mapping to DRB; SDAP layer at gNB does mapping from QoS Flows to DRBs.. UE does the same on UL • 5G CN and upper layers in the UE mark packets for transmission with a QoS flow identifier (QFI) • Each QFI associated with different QoS in terms of delay, reliability, etc • SDAP layer maps QoS flows to radio bearers, with PDCP/RLC of each RB configured appropriately for the QoS • MAC layer gives differentiated handling (e.g. priority) to traffic from different RBs • gNB has flexibility how to achieve the QoS RLC PDCP UE MAC SDAP PDCP RB1 RB2 RLC PDCP gNB MAC SDAP PDCP RB1 RB2 RLC RLC Role of SDAP Role of SDAP
- 16. 16-07-2021 16 • PDCP PDUscan be duplicated for transmission over 2 RLC bearer • Motivated to enable the reliability/delay requirements for URLLC applications • In case of carrier aggregation (CA) – Restrictions configured in the MAC ensure that duplicated data is transmitted via different component carriers • In case of dual connectivity (DC) – RLC bearers are mapped to different cell groups (i.e. MCG and SCG) RLC MAC SDAP PDCP RLC bearer 2 RLC RLC bearer 1 RLC SDAP PDCP RLC bearer 2 RLC RLC bearer 1 MAC MAC Different CCs Cell group 1 Cell group 2 Duplication - CA case Duplication - DC case PDCP in 5G NR PDCP in 5G NR Encryption and Integrity Protection roles continue as in LTE; DRB integrity protection added; ROHC configured as needed; duplicate handling is the major new role in NR PDCP MAC in 5G NR MAC in 5G NR • Similar functionality compared to LTE MAC: – Multiplexing and demultiplexing of data from different radio bearers to the transport blocks that are carried by the physical layer – Priority handling between data from different radio bearers – Error correction through Hybrid ARQ. – Discontinuous reception (DRX) • Key differences compared to LTE MAC – Functionality to support beam based operation for high frequent operation. – More flexible UL configured grants – MAC PDU format optimised to enable pre-processing and facilitate low delay
- 17. 16-07-2021 17 • Beam failuredetection and recovery – UE Phy layer monitors beam failure detection (BFD) reference signals to determine a beam failure – On beam failure detection the UE MAC layer initiates beam failure recovery – Selects a suitable beam on which to attempt recovery – Performs random access procedure • Beam management – Mobility between beams is performed by a combination of Phy and MAC signalling – RRC signalling involved only to provide a measurement configuration (e.g. configuration of the reference signals to be measured, etc) MAC in 5G NR – Support for beamforming MAC in 5G NR – Support for beamforming gNodeB – C/U Plane gNodeB – C/U Plane Source: rcf-wireless
- 18. 16-07-2021 18 E1 gNB-DU gNB-CU-CP F1-C F1-U gNB gNB-CU-UP gNB-DU gNB Controland User plane Split – Multi DU-CU Flexibility in handling control and user plane; more flexibility in building a small cell Each gNB-DU can in turn support multiple cells Can mixing and matching products in the RAN work?.. Can virtualized software implementation of some RAN functions meet performance requirements? 5G RAN RAN Deployment Options
- 19. 16-07-2021 19 5G Architecture Options 5GArchitecture Options EPC Next Gen Core LTE NR Many options for integrating LTE and 5G system being discussed Non-standalone 5G i.e., using LTE control plane is likely to be the first version EUTRAN-NR Dual Connectivity (EN-DC) likely to be popular in the initial deployments 5G Deployment Options 5G Deployment Options • There are mainly six deployment options in both SA and NSA modes. • Option-5 using 5GC and LTE ng-eNB access • Option-3 using EPC and LTE eNB acting as master and NR en- gNB acting as secondary; • Option-4 using 5GC and an NR gNB acting as master and LTE ng- eNB acting as secondary Source: GSMA SA NSA • Option-7 using 5GC and an LTE ng-eNB acting as master and an NR gNB acting as secondary.
- 20. 16-07-2021 20 5G Architecture –First Deployments .. Some options 5G Architecture – First Deployments .. Some options Source: GTI Big load on LTE eNB to handle all 5G traffic along with demands on X2 Can split traffic between 5G and LTE depending on coverage.. Lighter effect on X2 Master Cell Group (MCG) and Secondary Cell Group (SCG) Bearers 5G Architecture – EN-DC 5G Architecture – EN-DC Source: Rohde and Schwarz MN is LTE eNB responsible for NAS connection, handover etc.
- 21. 16-07-2021 21 Operator Evolution Path– Option 1 (NSA Based) Operator Evolution Path – Option 1 (NSA Based) Source: Nokia Bring in 5G core network and use 5G NR to offer the full power of 5G to verticals while keeping NSA option for legacy devices Upgrade to option 4 would allow full fledged 5G offerings with eLTE as an secondary node; important to have good 5G coverage for this Delays need for eLTE Operator Evolution Path – Option 2 (NSA Based) Operator Evolution Path – Option 2 (NSA Based) Source: Nokia Upgrade to option 5 would allow 5G core network services for eLTE; option 7x becomes useful when LTE spectrum has wide coverage Can get low-band NR carrier later in the deployment; LTE/eLTE can maintain coverage
- 22. 16-07-2021 22 Operator Evolution Path– Option 3 (NSA based) Operator Evolution Path – Option 3 (NSA based) Source: Nokia Relying on LTE/eLTE to remain the anchor; this might be due to spectrum issues with NR and till low-band NR spectrum is obtained; safer to keep LTE operating in lower band as the master; offering true 5G experience will take time with this option Early on eLTE support needed; NR master carrier can come later Operator Evolution Path – Option for an SA approach Operator Evolution Path – Option for an SA approach Source: Nokia Focus on getting to a true 5G solution without upgrading LTE Initial peak bit-rate will be lower than NSA solutions; but with NR- NR CA, it will get higher
- 23. 16-07-2021 23 What should anoperator do? What should an operator do? 5G Spectrum Can operator get low-band 5G NR spectrum to get good coverage? 5G CN Business and technical considerations for rolling out a 5G CN? eLTE Does it make sense to upgrade to eLTE? Will devices be available? SA support Will there be devices ? Spectrum refarming When can 2G/3G be retired and spectrum be used for 5G? Comparisons between NSA and SA Options Comparisons between NSA and SA Options Source: Nokia
- 24. 16-07-2021 24 5G – 3GPPSpecification 5G – 3GPP Specification Title Spec Series Link Spec Number System Architecture for the 5G system 23 Series https://www.3gpp.org/DynaReport/23-series.htm 23.501 Procedures for the 5G System 23 Series https://www.3gpp.org/DynaReport/23-series.htm 23.502 Service requirements for next generation new services and markets 22 Series https://www.3gpp.org/DynaReport/22-series.htm 22.261 Technical Specifications and Technical Reports for a 5G based 3GPP system 21 Series https://www.3gpp.org/DynaReport/21-series.htm 21.205 Radio related specifications addressing only NR 38 Series https://www.3gpp.org/DynaReport/38-series.htm Radio related specifications addressing aspects affecting both LTE and NR 37 Series https://www.3gpp.org/DynaReport/37-series.htm NR; NR and NG-RAN Overall Description 38 Series https://www.3gpp.org/DynaReport/38-series.htm 38.300 NR; Multi-connectivity; Overall description 37 Series https://www.3gpp.org/DynaReport/37-series.htm 38.340 NG-RAN; Architecture description 38 Series https://www.3gpp.org/DynaReport/38-series.htm 38.401 Thank You E-mail: devadas.pai@nanocellnetworks.com