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

Trace the rise of 2G cellular networks, detailing the ETSI-created GSM standard (1991), digital voice with sampling, and features like encryption, roaming, SMS, and internet data.

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.

Base transceiver station (BTS) connects the mobile station to the network, encrypts and decrypts voice, uses GMSK modulation, pages for calls, and reports power measurements to the base station controller.

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.

The visitor location register holds temporary mobile data for the current MSC area, reducing burden on the home location register (HLR) by transferring data as devices move between VLR areas.

Explore how the OMC monitors faults and alarms in the mobile network, configures new equipment, and stores performance and alarm data for at least one year.

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.

Differentiate GSM traffic channels from control channels and explain how traffic channels carry voice or data. Explain how control channels handle signaling for registration, handover, and call setup and maintenance.

Explain how msc areas subdivide into location areas, location area size balances paging with updates, and the location area identifier uses mobile country code and mobile network code.

The base station identification code, a 3-bit network color code plus a 3-bit base station color code, is broadcast on SCH to differentiate neighboring stations using the same frequencies.

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.

3GPP, formed in 1998, standardizes mobile systems under ITU with vendors and operators, and introduced UMTS in 2001 as wideband CDMA radio access technology.

Compare fdma, tdma, and cdma by showing fdma uses separate frequency channels, tdma uses time slots, and cdma uses unique codes, with wideband cdma (wcdma) using 5 megahertz channels.

Multiply a low-rate signal by a high-rate spreading code to create a wideband signal. Despread at the receiver using the same code to recover the signal and suppress interference.

Examine the 3g core network evolution across releases 99, 4, and 5 and the sgsn's role as the data network's msc, including authentication with the hlr and authentication center.

Explore how intelligent networks manage prepaid charging in the 3G core network by loading prepaid balance, billing calls, and connecting postpaid billing through a charging gateway linked to the GGSN.

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 4g wireless access technology and how orthogonal frequency division multiplexing enables downlink via OFDMA and uplink via SC-FDMA, balancing amplifier costs between user equipment and eNB.

Learn basics of orthogonal frequency division multiplexing, where subcarriers at carrier frequencies 1, 2, and 3 are orthogonal to eliminate interference and boost LTE bandwidth efficiency at 15 kHz spacing.

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.

Understand how the resource element defines the smallest unit of a resource block in LTE, formed by one subcarrier in frequency and one symbol in time.

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.

The 4G mobility management entity manages user context, authenticates UEs with HSS keys, establishes and manages EPS bearers, and transfers context between MMEs as devices move across tracking areas.

the pdn gateway assigns ip addresses after eps bearer setup, connects the core to the internet, anchors handovers, performs deep packet inspection, and marks diffserv qos for traffic.

Explore how the home subscriber server functions as the central 4G user database, enabling authentication, QoS profiles, roaming rules, and MME-directed calls.

Explore how 4G legacy architecture used physical network function nodes like gateway and serving gateway, revealing bulky proprietary hardware, high costs, and scalability challenges requiring more hardware.

Explore how physical network functions evolved into virtual network functions, introduced by ETSI in 2012 as network function virtualization, deployed on commercial off-the-shelf hardware for cost savings.

Discover how telco clouds virtualize core networks with cots servers and hypervisors, scale with racks for high availability, and are managed by the OpenStack cloud management system.

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 massive MIMO and beam forming at base stations, enhancing coverage and data rates with antenna arrays, and compare single-user and multi-user MIMO across sub-6 GHz and millimeter-wave bands.

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.

Understand how the network slice selection function (NSSF) coordinates with the EMF to inform a mobile about the network slice and enable access to the required service in 5G networks.

The network exposure function exposes 5G core capabilities to external application function, with NRF authenticating and authorizing the external application function and acting as a middleman for secure data exchange.