All Articles
60 technical articles and tutorials spanning 5G NR fundamentals, 5G Advanced, 6G research, Open RAN, and AI in telecom.
What Is 5G? The System Behind the Label
Strip away the marketing and 5G is two specified systems — NR and the 5G Core — built by 3GPP against ITU-R's IMT-2020 requirements. What those requirements were, what shipped, and where the releases stand.
What Is 5G-Advanced? Releases 18 to 20 Without the Branding
5G-Advanced is a release name, not a generation: the same NR and 5G Core, extended from Release 18 with AI/ML, energy saving, new mobility and device classes. What each release carries and why it is 6G's proving ground.
MEC: What Multi-Access Edge Computing Actually Shortens
MEC moves the UPF and the application towards the RAN. It shortens transport, not the air interface — how 3GPP steers traffic to an edge host, what happens when the UE moves, and where deployments go wrong.
5G NR Architecture: Nodes, Interfaces and the Protocol Stack on One Page
The whole NG-RAN picture before the detail: the three domains, the interfaces between them, what each protocol layer is responsible for, and exactly where each one terminates once the gNB is split.
IMT-2030 Capabilities: Nine Enhanced, Six New
M.2160 read as the successor to M.2083: which of the IMT-2020 capabilities were carried forward and by how much, which six have no predecessor, and why none of the numbers mean anything until the requirements report binds them to a test environment.
What Will Actually Change in 6G?
Most of the radio you already know survives the generation change. Five things do not — sensing, model lifecycle, upper mid-band planning, energy as a scheduled quantity, and satellite access inside the same system.
NR SRS: The Uplink Signal That Shapes the Downlink
In TDD, what the gNB learns from a UE's sounding reference signal is what it uses to build the downlink beam. How reciprocity works, why it fails in FDD, and what the four SRS usages are actually for.
NR Random Access: How a UE Gets Its First Grant
Every uplink transmission in NR is scheduled — except the first one. How the four-step RACH exchange breaks that circularity, why contention resolution cannot be skipped, and what two-step RACH actually buys.
NR PUSCH: The Uplink Is Not a Mirror of the Downlink
PUSCH looks like PDSCH turned around, and the differences are where the engineering is: a choice of waveform, a power-limited transmitter, and a grant that costs a round trip unless you configure one in advance.
NR PUCCH: Why Uplink Control Needs Five Formats
PUCCH carries anything from a single HARQ bit to a full CSI report, from the cell centre to the edge. No single format spans that, which is why NR defines five — and how the network picks between them.
NR Beam Management: What Happens When the Beam Misses
At FR2 a link can fail without the UE moving and without the cell changing. How P1, P2 and P3 narrow a wide sweep to an aligned pair, and why beam failure recovery exists as a separate mechanism from handover.
Massive MIMO vs Beamforming: Two Different Gains from One Array
They are not alternatives. One concentrates energy and buys coverage; the other sends parallel streams and buys capacity. Which one an array actually delivers is decided by the channel, not the datasheet.
5G MAC Scheduling Explained in 10 Minutes
What the MAC layer actually decides every slot: the five decisions behind a grant, why logical channel prioritisation is the part everyone skips, and how the uplink works around not knowing what the UE is holding.
5G NR Waveforms: CP-OFDM and DFT-s-OFDM, and When the Uplink Should Use Which
Why NR uses CP-OFDM everywhere but keeps DFT-s-OFDM as an uplink option, what PAPR really costs, and how the network chooses per UE.
5G NR Transmitter and Receiver Chain: Following the Bits From MAC to Antenna and Back
A block-by-block walk through the NR physical-layer transmit chain and its mirror-image receiver, explaining what each stage does and why it sits where it does.
5G NR Synchronisation Signals (PSS and SSS): How a Phone Finds a Cell From Nothing
PSS and SSS explained from the UE's point of view: what each signal gives the receiver, how the PCI is built from them, and why NR has 1008 cell identities.
5G NR SS/PBCH Blocks and Bursts: Beams, Timing and the 5 ms Window
How PSS, SSS and PBCH are packaged into one SSB, how multiple SSBs form a burst set for beam sweeping, and the Case A–E timing patterns.
5G NR Resource Blocks and Bandwidth Parts: CRB, BWP, PRB and VRB Finally Untangled
Four kinds of resource block, one coordinate system: how Point A, common resource blocks, bandwidth parts, physical and virtual resource blocks fit together, and why NR needed all four.
5G NR Radio Frames, Slots and Mini-Slots: How Time Is Divided
The 10 ms frame, the numerology-dependent slot, the 14-symbol structure, the extended-CP exception, and why NR added mini-slots.
5G NR PDSCH From Bits to Resource Elements: MCS, TBS, Processing, Allocation and the Four Special Cases
A step-by-step tour of the PDSCH: how the MCS tables work, how the transport block size is computed, the physical-layer processing chain, frequency and time allocation types, resource block bundling, pre-emption, reserved resources and slot-aggregation repetition.
5G NR PDCCH Demystified: CORESETs, Search Spaces and Every DCI Format
A clarity-first walk through the PDCCH: how control channels are built from CCEs, what a CORESET and a search space really are, how SIB1's search space is derived from the MIB, and what each DCI format (0_0, 0_1, 1_0, 1_1, 2_0–2_3) actually does.
5G NR PBCH and the MIB: The 32 Bits That Unlock a Cell
What the PBCH carries, why every bit in the MIB is there, how the physical layer adds timing bits, and how the UE goes from PBCH to SIB1.
5G NR Numerology: The One Parameter That Shapes the Whole Air Interface
Why 5G NR has five subcarrier spacings instead of LTE's one, what each value buys you, and how μ ripples through symbol, slot and frame timing.
5G NR Modulation: From π/2-BPSK to 1024QAM, and Why Each One Exists
The modulation schemes NR supports on each link, how the MCS index ties modulation to code rate, and the design reasoning behind π/2-BPSK, 256QAM and 1024QAM.
5G NR Frequency Raster: NR-ARFCN, the Channel Raster and the Synchronisation Raster (GSCN)
Two rulers over the spectrum: the fine channel raster that positions carriers (NR-ARFCN) and the coarse synchronisation raster that positions SSBs (GSCN) — what each is for, the formulas, and why NR separated them.
5G NR Downlink Reference Signals: DM-RS, CSI-RS, TRS and PT-RS Without the Headache
What each downlink reference signal is for, where it sits, and how NR replaced LTE's always-on CRS with four purpose-built signals: DM-RS (for PBCH, PDCCH and PDSCH), CSI-RS, TRS and PT-RS.
5G NR Downlink Channel Mappings: The Map You Need Before Anything Else
How logical, transport and physical channels fit together in the 5G NR downlink, and why NR needs fewer physical channels than LTE.
5G NR Cyclic Prefix: The Insurance Premium Every OFDM Symbol Pays
What the cyclic prefix does, how long it is at each numerology, why two symbols per half-subframe are slightly longer, and why the extended CP exists only at 60 kHz.
5G NR Channel Bandwidths: From Licensed MHz to Usable Resource Blocks
The supported channel bandwidths in FR1 and FR2, the transmission bandwidth configuration tables, how guard bands work, and why NR reaches ~98% spectrum utilisation.
5G NR Antenna Ports and Quasi Co-Location: What the UE Is Really Being Told
Antenna ports are not antennas, and QCL is not co-location. A plain-language explanation of both concepts, the four QCL types, TCI states, and why QCL Type D is the key that unlocks mmWave.
THz Communication: Why 6G Is Looking Past mmWave
What sub-THz and THz bands offer 6G, why molecular absorption and path loss make coverage brutal, the hardware problems that remain unsolved, and a realistic deployment timeline.
Semantic Communications: Sending Meaning Instead of Bits
What semantic communication actually proposes, where task-selective traffic reduction genuinely pays, and the metrics, robustness and interoperability problems still in the way.
Non-Terrestrial Networks: 3GPP Satellites, Delay Budgets, and Direct-to-Device
How 3GPP adapted NR for satellites: LEO/MEO/GEO trade-offs, the timing advance and HARQ changes long delays forced, transparent versus regenerative payloads, and what direct-to-device really delivers.
Integrated Sensing and Communication: Turning the Radio Network Into a Sensor
How ISAC extracts environmental information from radio signals, why massive MIMO and wide bandwidth make it viable in 6G, and the trade-offs standing between the concept and deployment.
Digital Twins in Telecom: A Proving Ground for the Live Network
What makes a network digital twin useful rather than decorative: the fidelity trade-off, high-value use cases, the data foundations required, and how twins support safe closed-loop automation.
AI-Native Networks: Designing 6G for Intelligence from the Start
The difference between AI-assisted and AI-native networking, why the data pipeline matters more than the models, and what explainability actually means in network operations.
What Is Open RAN? The Architecture, the Promise, and the Fine Print
Open RAN in plain terms: what operators are actually trying to achieve, what the architecture changes, and why 'open' does not mean plug-and-play.
What Is 6G? Targets, Timeline, and What's Actually Different
6G explained without the hype: the IMT-2030 capability targets, the four technology pillars, the 3GPP standardisation timeline, and which claims deserve scepticism.
What Is 5G NR? Numerology, Frequency Ranges, and the Flexible Frame
5G NR explained for engineers: scalable numerology, FR1 and FR2, the flexible slot structure, bandwidth parts, and what actually changed from LTE.
5G Interview Questions: What Gets Asked and How to Answer It
A structured 5G interview guide: the questions that actually come up across radio, RAN, core and QoS, worked troubleshooting and system-design scenarios, and a framework for answering well.
5G Scheduling Algorithms: Round Robin, Proportional Fair, and What Real Schedulers Do
How the gNB MAC scheduler decides who transmits: the classic algorithms, why Proportional Fair became the baseline, and how QoS-aware scheduling handles URLLC and eMBB together.
RRC States in 5G: Why RRC_INACTIVE Exists
The three NR RRC states explained: what IDLE, CONNECTED and INACTIVE each cost in power and latency, and the specific problem RRC_INACTIVE was designed to solve.
5G RedCap: Filling the Gap Between NB-IoT and Full 5G
What RedCap actually reduces — bandwidth, antennas, duplex and processing — which devices it targets, and how it compares to LTE Cat-1, eMTC and NB-IoT.
5G QoS Flows: 5QI, ARP, Reflective QoS, and How Policy Reaches the Air
A deep dive into the 5G QoS model: what 5QI actually specifies, how GBR and delay-critical GBR differ, the role of ARP and Session-AMBR, and how reflective QoS avoids signalling.
PDU Sessions in 5G: What They Are and How QoS Rides on Top
A PDU Session is the 5G Core's unit of data connectivity. Here's how one gets established, what lives inside it, and how QoS Flows map down to radio bearers.
Open RAN Tutorial: From Architecture to Your First xApp
A complete hands-on path into Open RAN: the architecture and interfaces that matter, an acronym decoder, standing up a lab with open-source components, writing an xApp against E2SM-KPM, and adding A1 policy.
O-RAN Architecture: Interfaces, RIC, and the Functional Split
A technical reference for the O-RAN architecture: the O-CU/O-DU/O-RU split, the O1, O2, A1, E2 and Open Fronthaul interfaces, and how the two RICs divide the control problem.
NSA vs SA: The Two Ways to Deploy 5G, and Why It Matters
Option 3x versus Option 2 explained: how NSA anchors 5G on LTE, what SA unlocks with the 5G Core, and which 5G features simply do not exist on an NSA network.
5G Network Slicing: S-NSSAI, Slice Selection, and What Actually Gets Reserved
How 5G network slicing works end to end: S-NSSAI structure, NSSAI types, the registration-time selection procedure, and why requesting a slice is not the same as getting resources.
Massive MIMO: Where the Capacity Gain Actually Comes From
How massive MIMO multiplies 5G capacity: spatial multiplexing versus beamforming, why MU-MIMO is the real gain, what 64T64R means, and why TDD reciprocity matters so much.
HARQ in 5G NR: Soft Combining, Process IDs, and Flexible Timing
How HARQ combines FEC with retransmission, why soft combining beats plain ARQ, and what NR's K1/K2 timing flexibility changes for latency and URLLC.
The gNB Explained: CU/DU Split, Interfaces, and What Changed from the eNB
What a gNB actually is: the CU/DU functional split, the F1, E1, Xn and NG interfaces, how it differs from an LTE eNB, and the deployment models operators actually use.
Generative AI in Network Operations: Where It Helps and Where It Bites
Practical uses for LLMs in the NOC: triage, log summarisation, config generation and spec retrieval — plus the grounding, guardrails and failure modes that decide whether it works.
Dual Connectivity: EN-DC, Bearer Types, and Talking to Two Nodes at Once
How dual connectivity works: master and secondary nodes, the four MR-DC variants, MCG/SCG/split bearer types, and why DC tolerates backhaul that carrier aggregation cannot.
Carrier Aggregation Tutorial: Configure, Measure, and Troubleshoot CA
A complete practical walkthrough of carrier aggregation: decoding UE band combinations, configuring PCell and SCells, timing advance groups, measuring real gain, and diagnosing every common activation failure.
Carrier Aggregation in 5G NR: PCell, SCells, and Why Throughput Doesn't Just Add Up
How 5G NR carrier aggregation works: component carriers, the PCell/SCell relationship, intra- and inter-band types, and why aggregate throughput rarely matches the sum of the parts.
Beamforming in 5G: Analog, Digital, Hybrid, and Keeping the Beam Aligned
How 5G beamforming works: array gain, the three architectures and their RF-chain economics, SSB beam sweeping, and why beam management is a continuous process.
AMF vs SMF vs UPF: Who Does What in the 5G Core
A side-by-side breakdown of the three central 5G Core functions: what each one owns, how they interact during registration and session setup, and why the split matters for slicing and edge.
AI-RAN: What Changes When the Radio Network Learns
AI-RAN explained for RAN engineers: the three meanings of the term, where machine learning genuinely beats rule-based automation, and the compute and reliability problems in the way.
5G Core Architecture: The Service-Based Design Explained
How the 5G Core works: service-based architecture versus point-to-point reference points, the network functions and what each does, control/user plane separation, and how slicing falls out of the design.