5G NR (New Radio) Technical Training-A Deep Dive

OFDMA powers the air interface between user equipment and the GNP for uplink and downlink. At cell edges, uplink may use single carrier FM or FDD for more efficient amplification.

Explore basics of orthogonal frequency division multiplexing and its subcarriers that isolate signals in frequency. Compare OFDM with FDM, define subcarrier spacing Delta F, and note 4G and 5G differences.

Explore how ofdm converts serial data to parallel streams, maps bits to symbols on subcarriers, and modulates with carrier frequencies to form the time-domain signal. Note the practical multiplier challenges.

Explore a simplified ofdm model for 5g nr, showing serial-to-parallel conversion, subcarriers, symbol mapping, ifft/fft processing, carrier upconversion, and data recovery.

Explains multipath propagation and inter-symbol interference. Shows the cyclic prefix reduces ISI by copying the end of a symbol to the start, and notes extended prefixes suit large cells.

Explore 5g nr flexible numerology and frame structure by using mu to set subcarrier spacings from 15 to higher values, and see how frames, subframes, and slots adapt with cp.

Explore how 5G NR forms a time-frequency grid where bandwidth sets subcarriers and data rate, with resource blocks as 12 consecutive subcarriers and resource elements as the smallest units.

Explore 5G FDD and TDD operation, including supplementary downlink and supplementary uplink bands to boost downlink throughput and address cell-edge uplink coverage using lower frequency bands.

Understand 5g nr slot formats and slot format indicators (sfi) that define uplink, downlink, or flexible symbols, with examples and how fdd and tdd affect band usage.

Analyze 5g nr self-contained slots including uplink, downlink, and guard. Learn how downlink control and data, uplink control, enable scheduled uplink and within slot acknowledgments for ultra reliable low latency.

Explore mini slots in 5G NR, fractions of a slot that carry 2, 4, or 7 symbols in uplink or downlink, enabling low-latency scheduling and high data rates in FR2.

Explain how 5G modulation schemes use 4-, 16-, 64-, and 256-QAM to carry 2, 4, 6, and 8 bits per symbol on a resource element.

Modulation and coding in 5g nr adjusts modulation schemes by channel conditions, using high modulation with weak coding in good channels and low modulation with strong coding for bad channels.

Explore how 5g nr uses mixes of modulation and coding schemes organized in 64 qam and 256 qam tables to balance spectral efficiency, code rate, and reliability across channels.

Use lower subcarrier spacing for large cell sizes to lengthen the cyclic prefix and prevent inter-symbol interference from direct and reflected paths.

Explore the cell size and subcarrier spacing trade-off in 5g nr: larger cells use smaller spacing; small cells use higher spacings at higher frequencies because of phase noise and Doppler.

Explain why 5g nr favors tdd over fdd by using channel reciprocity to estimate downlink quality from uplink measurements and adjust gnb downlink transmissions.

Explore 5g frequency bands in fr1 and fr2, including fdd, tdd, uplink and downlink, supplementary uplink and downlink, with lower frequencies improving uplink coverage and tdd bands 77, 78, 79.

Explore how MIMO and beamforming use multiple antennas to form sharp beams, boost throughput, and enable single-user, multi-user, and massive MIMO at the base station.

Explore the 5g nr downlink transmission chain from gnb to user equipment, detailing transport blocks, codewords with crc and fec, scrambling, modulation, layer mapping, mimo, and resource element mapping.

Explore analog beamforming in 5G NR, where phase control of antenna subarrays creates directed beams, highlighting its simplicity and low power use alongside challenges for multi-user MIMO and scalability.

Hybrid beamforming merges analog phase-shifted subarrays with digital precoding for millimeter-wave mimo. Enable one rf chain per subarray to deliver sharp, high-gain beams and reduce interference via nulling.

5G NR active antenna system uses a matrix of sub arrays with dual polarization, combining +45 and -45 polarizations via separate RF chains to enable four transmit and four receive.

Explore 5g nr active antenna system configurations, including 8t8r and 64t64r. Observe 32 sub areas in an eight-by-four matrix, each with two chains, totaling 64 transmit and 64 receive.

Compare how frequency affects antenna size across sub six gigahertz and millimeter wave, using 3.5 gigahertz with 343 mm and 28 gigahertz with 43 mm dimensions.

Explore the virtualized representation of 5g antennas, showing how large-scale arrays map antenna subarrays to virtual cross-polarized elements with shared transmit and receive radio frequency chains.

Explore how 5G antennas create 3D beams to boost capacity and coverage with rural, urban, and hotspot configurations for varying density and data-rate needs.

Explore single panel and multi panel antennas in 5g nr, defining N1, N2, and G for panel counts, including two-panel configurations, and compare uniform vs non uniform layouts.

Explore how 5G NR defines a grid of beams to cover a cell, with horizontal and vertical oversampling factors yielding the total beams and orthogonal beams.

Explore downlink MIMO in sub6 ghz, where single-user MIMO delivers up to eight layers using four beams and two polarizations; multi-user MIMO supports up to 16 layers.

Downlink mimo in millimeter-wave uses single and multi panel antennas; single user mimo provides up to two layers, multi user mimo up to 16 layers, with carrier aggregation across panels.

Explain why downlink multiuser MIMO is limited to 16 layers despite 64 transmit antennas due to interference and algorithm limits; single-user MIMO faces constraints: 16 receive antennas and RF chains.

Explore uplink mimo across sub-6 and millimeter-wave bands, noting single-user up to four layers with two beams for two polarizations, and vendor-specific multi-user mimo with one codeword per ue.

Describe how the CSI report is calculated from downlink CSI-RS and uplink sounding signals in FDD and TDD, guiding MIMO layers and beamforming through rank indicator and channel quality indicator.

Utilize tdd with large antenna ports to exploit channel reciprocity, reducing the burden of extensive csi-rs and uplink csi reports and enhancing mimo and beamforming performance.

Distinguish type one CSI for single-user M.O. and type two CSI for multi-user M.O., with standard resolution CSI and high resolution CSI, and define pre-coding matrix W as W1 W2.

Explain how Type I CSI enables rank-two MIMO transmission with two layers by using a long-term W1-based beam selection and a short-term W2-based beam refinement and CO phasing.

Explain why co-phasing transmitter layers from the GNB to user equipment aligns receiver phases, achieving the best SNR across beams and polarizations using two metrics.

Explore type-I CSI subtypes, including single-panel and multi-panel antennas, where the W1 matrix selects one beam per panel, and W2 handles beam spacing for nonuniform panel arrangements.

Explain Type II CSI, a high resolution CSI optimized for massive multi-user MIMO beam selection, using W = W1 W2 to form and weight beam sets.

Explore how sub arrays in a panel antenna determine required KCI ports, using n1, PN2, and polarization; four ports need four KCI ports, while 2-by-2 needs eight, up to 32.

Explore beamformed CSI-RS based downlink SU-MIMO: four beams carry CSI signals; the UE selects the best beam via CSI-RS resource indicator and reports coding metrics, rank, and CQI.

Explore how the sounding reference signal (SRS) is transmitted by the UE in uplink using antenna switching for TDD single-user MIMO, enabling precoding metrics estimation and CSI for downlink.

Explore uplink transmission schemes in 5G NR, including codebook based and non codebook based methods, with GNP configuring the UE’s uplink scheme via radio resource signaling and supporting four layers.

Codebook based uplink scheme uses sounding reference signals across beams, selects the beam via sri, and computes rank indicator and transmit recording metrics indicator for uplink on uplink shared channel.

Explore the non codebook based uplink scheme in TDD mode, where the UE measures sounding reference signals, selects a recording matrix and beams, and the GNB grants a precoding matrix.

Explore the 5G NR control plane protocol stack, detailing direct signalling links between the user equipment, EMF, and GMB, and comparing ness and RC signaling in the access network.

Trace the 5g nr user plane protocol stack and how ip packets from the upf traverse sdap, sdu/pdu boundaries, rlc, mac, and the physical layer to support qos flows.

Combine the 5G NR protocol stack's data plane and signaling plane in a single diagram, implemented on network and user equipment, mapped to the OCI model's layers one to three.

5g nas layer implements nas signaling between ue and amf, covering mobility management and session management, including registration, authentication, area updates, and video session QoS management.

Learn how the radio resource control layer manages system broadcast and paging messages, establishes radio bearers for signaling and data, and handles security, mobility, and handover via measurement reports.

Explain how the service data adaptation protocol (sdap) layer maps quality of service flows to data radio bearers in downlink and uplink, including reflective quality of service flows.

Learn about the 5g nr pdcp layer, including header compression and hdcp encryption. Explore integrity protection, dual connectivity split between master and scan base stations, with reordering and duplicate detection.

Explain how the Mac layer multiplexes and prioritizes logical channels, schedules them, and implements a hybrid earc retransmission mechanism, and describe concatenation of sdus into Mac transport blocks for transmission.

Learn how 5g nr horizontal gnb disaggregation splits the baseband unit into a centralized unit and a distributed unit, with mid-haul links and virtualization on off-the-shelf hardware.

Explore how to split BBU/RAN functions between centralized and distributed units and the remote radio unit over front haul, covering PDCP, RLC, MAC, PHY, RF, and their pros and cons.

Explains ran split option 2, centralizing the hdcp layer while most functions stay in the remote radio unit, reducing fronthaul bitrate and latency and enabling dual connectivity for low-latency services.

Explore RAN split option 8, where PDCP, RLC, MAC, and physical headers are added across centralized-distributed units, increasing fronthaul rate and enabling virtualization with ERC timing under 5 ms.

Split option six centralizes dhcp, rlc, and mac layers; physical and rf layers are implemented in the room, with mac-layer scheduling and a standardized network api interface for interoperability.

Examine how higher level RAN splits reduce fronthaul latency while allowing higher latency, and how lower level splits boost fronthaul data rates for capacity and coverage use cases.

Explain option 7.2x for 5g open ran, detailing physical layer split high/low and midhaul split between pdc and rlc layers. Highlight virtualization of mac and rc in cloud.

Explore the enhanced CPRI (e-CPRI) fronthaul protocol, a packet-based open interface. It can run over existing Ethernet LANs in urban indoor environments with minimal overhead.

Learn how dual connectivity enables user equipment to connect to a master base station and a secondary base station, using primary and secondary cells to carry signaling and data.

Compare 4g lte standalone with epc, mme, sgw, enb delivering VoLTE and data, and 5g standalone with amf, upf, master gNB, dual connectivity, and data/signaling split for hotspots.

Examine 5g non-standalone option 3, 3a, and 3x, anchoring signaling to the master eNodeB with a lte core and varying data bearer split across enhanced gNBs.

Compare the data bearer protocol stacks for option three, 3a, and 3x, highlighting splits at the master eNodeB or at the gNB, with 3x favored.

Explore 5G non-standalone option 4, with dual connectivity between a master gNB and ng-eNB, and data bearers split at the master gNB or the UPF.

Discover 5g non-standalone option seven, featuring a master gnb interfacing with the 5g core and data split at master cell group, UPF, or scan ri cell group for dual connectivity.

Analyze option five and six as unlikely standalone deployments, noting that full 5G benefits require both the 5G core network and the 5G access network.

Explain how fr1 and fr2 channel bandwidths, guard bands, and subcarrier spacings determine the transmission bandwidth and resource-block counts.

Learn how NR-ARFCN identifies a 5g channel by its center reference frequency, using a global raster and offsets including zero offsets for 0–3000 mhz and 15 khz for higher ranges.

Explain global and channel raster in 5g nr: above 3 ghz rasters align, below 3 ghz global raster is 5 khz and channel rasters can be 15 or 100 khz.

Explore bandwidth part in 5g, a set of resource blocks within bandwidth, enabling numerology variation with up to four downlink and four uplink parts, one active at a time.

Explore how 5G air interface resources are organized into time-frequency grids with frames, subframes, subcarriers, and multiple grids for uplink and downlink across varying subcarrier spacings and MIMO ports.

Explore the 5G NR air interface model, covering physical, transport, and logical channels and their mapping to MAC, RLC, and RRC layers within the OSI framework.

Examine 5g nr logical channels—dedicated, common, and broadcast—and how data and signaling use dedicated channels, while common and broadcast channels enable access and convey system information.

Explore how 5g nr transport channels multiplex control and data on downlink and uplink shared channels. See how common, dedicated control, and dedicated traffic channels map to these transport channels.

Convert information bits into electromagnetic signals using modulation and error correction in 5G NR physical channels, then transmit or receive via uplink and downlink shared channels.

Explore the demodulation reference signal (DM-RS) and its role in downlink and uplink channel estimation and coherent modulation for physical channels, with the physical random access channel as an exception.

Determine the DM-RS location in time and frequency domains for a resource block, comparing mapping types A and B, the L node value, and single versus double symbol DM-RS.

Illustrates how DM-RS location in the frequency domain depends on DMRS type and antenna ports, with six or four DM-RS symbols per PRB in a slot and port-wise blocking.

Compute CSI reports for downlink using CSI-RS signals that come in various types and patterns. Support beam management, measure time and frequency offset, and adapt density and port patterns accordingly.

User equipment transmits sounding reference signal in uplink to let the GMB compute channel state information. SRS uses 1–4 ports and 1–4 fpm symbols, with offset 0–5.

In 5G NR millimeter wave, phase tracking reference signals minimize phase synchronization errors, appearing only in resource blocks that carry data channels such as PDSCH and PUSCH.

Understand how 5G channels work by studying the procedures of cell acquisition, initial exchange access, scheduling of data transmissions, and Beijing.

Power on the user equipment to initiate 5G NR cell acquisition, discovering cells and decoding cell IDs and information via broadcast control channel and synchronization blocks on synchronization channel.

Learn how 5g nr cell acquisition uses beam sweeping to transmit an SSB burst set across multiple beams, with five millisecond duration and a 5-160 millisecond period.

Learn how the 5g nr ssb maps to the resource grid, with primary synchronization sequences, pbch placement, and dmrs-based power measurements to identify the strongest beam.

Explore how minimum system information enables cell access in 5g nr, using the minimum information block (mip) on pbch and system information block one (sib1) on pdsch, with pdcch.

Conveys master information block data: cell barred status, system frame number, and DMRS configuration for the PDSCH, and locates the core set zero PDCCH for the associated downlink.

Explore the 5g cell acquisition via the control resource set, detailing how the physical downlink control channel uses time–frequency resources and how the master information block locates core set zero.

Initiate the initial access by sending a preamble on the physical random access channel, then receive a downlink control response that assigns a temporary identity and establishes the RC connection.

Learn how data is scheduled in a 5G NR data call using the dedicated traffic channel, with the physical downlink and uplink shared channels coordinating data and signaling.

Revisit the core set concept in the downlink. A user can have up to 12 total core sets, with core set zero carrying minimum system information.