MOBINFSEC Logs

In soft handover (two different NodeBs) the uplink signals are combined in the RNC; in softer handover (two sectors of one NodeB) they are combined in the NodeB itself. The uplink gains performance for free, but every extra downlink link adds interference for other users. * Wher...

Quiz: MOBINFSEC / Mobility in GSM, UMTS & LTE | updated: Jul 14, 2026

Single-hop means the device reaches its destination (or a base station) in one wireless jump. Multi-hop means the signal must pass through intermediate wireless nodes. * The four single-hop / multi-hop x infrastructure combinations. * Single-Hop Multi-Hop Infrastructure-...

Quiz: MOBINFSEC / Wireless Communication | updated: Jul 14, 2026

UMTS consists of UE (User Equipment), UTRAN (radio access network), CN (Core Network), and the UMTS-PLMN (the operator's complete mobile network). * The four pieces and how they nest: the UE talks to the UTRAN over the air, the UTRAN connects to the CN, and the PLMN is the opera...

Quiz: MOBINFSEC / UMTS Architecture | updated: Jul 14, 2026

HLR = permanent subscriber master database; VLR = temporary database for visitors in an MSC's area; AUC = authentication/key center; GMSC = the gateway that connects the operator's network to external telephone networks. These subscriber-management and gateway elements were carri...

Quiz: MOBINFSEC / UMTS Architecture | updated: Jul 14, 2026

Control plane: the mobile talks to the local MME, which uses the IMSI to contact the home HSS and retrieve authentication, encryption, and service data. Data plane: two GTP tunnels — S-GW to base station (endpoint swapped on every cell change) and S-GW to home P-GW (the indirect-...

Quiz: MOBINFSEC / Mobility in GSM, UMTS & LTE | updated: Jul 14, 2026

SDMA is like people talking in different rooms; FDMA is like dog whistles at unhearable frequencies; TDMA is like taking turns speaking; CDMA is like recognizing a friend's voice in a crowd. * The four access schemes on the time-frequency grid (plus SDMA beams). * * FDMA, TDMA...

Quiz: MOBINFSEC / Modulation, Multiple Access & Power Control | updated: Jul 14, 2026

UMTS reuses the GSM core network concepts but renames and enhances the radio access components — Node B replaces BTS, RNC replaces BSC, and the core adds parallel circuit and packet domains. * The radio side was renamed and made more capable (MS→UE, BTS→Node B, BSC→RNC); the cor...

Quiz: MOBINFSEC / UMTS Architecture | updated: Jul 14, 2026

Hard handover breaks the old link before making the new one; soft handover connects the mobile to several NodeBs simultaneously; softer handover connects it to several sectors of the same NodeB. * UMTS Node B/RNC layout behind soft handover. — Tsaitgaist, CC BY-SA 3.0, via Wikim...

Quiz: MOBINFSEC / Mobility in GSM, UMTS & LTE | updated: Jul 14, 2026

From smallest to largest scope: intra-cell, inter-cell (intra-BSC), inter-BSC (intra-MSC), inter-MSC, inter-PLMN, and inter-system handover. * The six handover types by widening scope. * The taxonomy: # Type What changes 1 Intra-cell handover Another frequency or time slo...

Quiz: MOBINFSEC / Mobility in GSM, UMTS & LTE | updated: Jul 14, 2026

There is a fundamental tradeoff: higher data rates generally come with shorter range. Technologies optimize for one or the other. * Data rate vs range: higher speed usually means shorter reach. * The landscape by range category: Range Category Technologies Data Rate Indoo...

Quiz: MOBINFSEC / Wireless Communication | updated: Jul 14, 2026