5G, 4G LTE, 3G, 2G; Mobile/Cellular Networks For Beginners

GSM combines FDMA and TDMA as the access technology, with 200 kHz uplink and downlink channels, a 45 MHz offset, eight time slots per channel, and 900/1800/1900 MHz bands.

Identify mobile station, sim, imsi. Define the base station subsystem with bsc and bts, ABIS, and A interface, and the core network with msc and eir, vlr, hlr, auc.

The home location register serves as the central database for mobile subscribers, storing subscriber IDs, authentication keys, registration status, available services, and the current location within the VLR area.

Explore GSM channel types by distinguishing physical channels from logical channels, with uplink and downlink time slots, where the transmitted information type defines the logical channel.

Explore how edge 2.75g boosts data rates through modulation and coding adaptation, using gmsk or 8-psk across nine modulation coding schemes and sgsn/ggsn integration.

3g release 5 introduces the IP multimedia subsystem (IMS) to carry voice as IP packets over the IP network, with an option to use circuit-switched voice or IMS-based voice.

Trace the mobile terminated call flow in 3g from a fixed telephone to the user equipment, via gateway msc, hlr authentication, rnc paging, and ringing tone.

Explore how LTE uses resource blocks by combining twelve subcarriers in frequency with one slot in time, enabling downlink and uplink allocations within frames and subframes.

Discover how the evolved NodeB (eNB) manages radio transmission and resources with user equipment, performs admission control for resource blocks, encrypts and decrypts user data and signaling, and coordinates handovers.

Explore how 4G uses EPS bearers as IP tunnels from user equipment to the PDN gateway. Define QoS through data rate, latency, and priority for voice and data.

Outlines the three core 5G use cases: enhanced mobile broadband for high data rates, massive machine type communication for dense, energy-efficient device networks, and ultra-reliable low-latency for critical applications.

Explore how 5g nr uses ofdma between gnb and user equipment, with flexible numerology and subcarrier spacing (15/30/60/120 kHz) to mitigate doppler and phase errors, cyclic prefix concepts.

5G NR defines resource blocks in the frequency domain, consisting of 12 subcarriers; a resource element remains a unit defined in time and frequency as one subcarrier per OFDM symbol.

Explore how massive MIMO uses large antenna arrays at base stations to perform beam forming toward mobile users, increasing SNR and data rates.

Illustrates the separation of the control plane and the user plane in 5g networks, detailing gnb and upf roles, handover, authentication, connection management, and scalable capacity.

The AUSF authenticates user equipment in the 5g core by coordinating with the amf and udm to generate an authentication vector, issue a random challenge, and verify the response.

The policy charging function decides dynamic network policies by congestion and geolocation, throttling or blocking calls, managing service areas with SMF/AMF, and deciding user charging and quality of service.

Identify how the application function, an external server, communicates with the core network, specifically the PCF, to request a new packet flow, with IMS nodes illustrating voice over IP calls.