Top 29 3g Interview Questions You Must Prepare 07.Dec.2023

  • The cost of cellular infrastructure , upgrading base stations is very high
  • Needs different handsets.
  • Roaming and data/voice work together has not yet been implemented
  • Power consumption is high
  • Requires closer base stations and are expensive
  • Spectrum-license costs, network deployment costs and handset subsidies subscribers are tremendous.

The antenna gain depends on antenna model; in link budget we use around 17dBi.

Hard handover me that all the old radio links in the UE are removed before the new radio links are established. Hard handover can be seamless or non-seamless. Seamless hard handover me that the handover is not perceptible to the user. In practice a handover that requires a change of the carrier frequency (inter-frequency handover) is always performed as hard handover.

A TMA reduces system noise, improves up-link sensitivity and leads to longer UE battery life. Sensitivity is the minimum input power needed to get a suitable signal-to-noise ratio (SNR) at the output of the receiver. It is determined by receiver noise figure, thermo noise power and required SNR. Thermo noise power is determined by bandwidth and temperature, SNR is determined by modulation technique, therefore the only variable is noise figure.

TMA typically has a 12 dB gain; however, the effective gain comes from noise figure reduction and the gain is close or equivalent to the feeder loss.

  1. Overcrowding is relieved in existing systems with radio spectrum
  2. Bandwidth, security and reliability are more
  3. Provides interoperability among service providers
  4. Availability of fixed and variable rates
  5. Support to devices with backward compatibility with existing networks
  6. Always online devices - 3G uses IP connectivity which is packet based
  7. Rich multi media services are available

  • Packet data speed is higher in 3G, and it is up to 384 KBPS
  • Voice and sms speed is also 384 KBPS in 3G
  • 2G utilizes different switching techniques for voice and data, where as 3G uses single switching, irrespective of data
  • 3G has at least 2MB of data link of a mobile, where in 2G the data rate is in KBPS
  • 3G has WiMAX facility for faster VOIP and internet
  • 2G uses GSM TDMA technology with narrow band 200 KHz.
  • 3G uses CD-MA technology with broadband 5 MHz, with same frequency carrier and time.

High Speed Packet Access (HSPA) is a collection of two mobile telephony protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), that extends and improves the performance of existing WCDMA protocols. A further standard, Evolved HSPA (also known as HSPA+), was released late in 2008 with subsequent adoption worldwide into 2010.

Third generation (3G) wireless networks will offer faster data trfer rates than current networks. The first generation of wireless (1G) was analog cellular. The second generation (2G) is digital cellular, featuring integrated voice and data communications. So-called 2.5G networks 

offer incremental speed increases. 3G networks will offer dramatically improved data trfer rates, enabling new wireless applications such as streaming media.

Soft handover me that the radio links are added and removed in a way that the UE always keeps at least one radio link to the UTRAN. Soft handover is performed by me of macro diversity, which refers to the condition that several radio links are active at the same time. Normally soft handover can be used when cells operated on the same frequency are changed.

The uplink noise increases with the loading exponentially. When the up-link noise approaches infinity then no more users can be added to a cell - and the cell loading is close to 100% and has reached its pole capacity

WiMAX, an acronym for Worldwide Interoperability for Microwave Access, is a telecommunications protocol that provides fixed and fully mobile internet access. The current WiMAX revision provides up to 40 Mbps with the IEEE 802.16m update expected offer up to 1 Gbit/s fixed speeds. (WiMAX is based on the IEEE 802.16 standard, also called Broadband Wireless Access). The name WiMAX was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard.

  1. Most popular standard for mobile telephony systems, originated from Group Special Mobile
  2. The ubiquity of GSM enables the international roaming arrangements among mobile phone operators.
  3. Both signaling and speech channels are digital, and thus GSM is considered as 2G mobile phone system.
  4. GSM standard benefited customers the ability to roam and switch carriers without replacing the hand sets and network operators.
  5. GSM implements low-cost implementation of Short Message Service

The maximum path loss is dependent on the service and vendor recommendations; typically it is in between 135 to 140dB for urban areas and between 150 to 160dB for rural areas.

Evolution-Data Optimized or Evolution-Data only, abbreviated as EV-DO or EVDO and often EV, is a telecommunications standard for the wireless trmission of data through radio signals, typically for broadband Internet access. It uses multiplexing techniques including code division multiple access (CDMA) as well as time division multiple access (TDMA) to maximize both individual user's throughput and the overall system throughput. It is standardized by 3rd Generation Partnership Project 2 (3GPP2) as part of the CDMA2000 family of standards.

Digital Enhanced Cordless Telecommunications (DECT), known as Digital European Cordless Telephone until 1995, is an ETSI standard for digital portable phones (cordless home telephones), commonly used for domestic or corporate purposes. It is recognised by the ITU as fulfilling the IMT-2000 requirements and thus qualifies as a 3G system. Within the IMT-2000 group of technologies, DECT is referred to as IMT-2000 Frequency Time (IMT-FT)

The International Telecommunication Union is the eldest organization in the UN family still in existence. It was founded as the International Telegraph Union in Paris on 17 May 1865 and is today the leading United Nations agency for information and communication technology issues, and the global focal point for governments and the private sector in developing networks and services.

  1. For GSM and CDMA wireless networks
  2. It's responsibility is to authenticate and authorize subscribers and their services.

RSCP stands for Received Signal Code Power - the energy per chip in CPICH averaged over 512 chips.

  1. Packet oriented mobile data service available to the users of 2G cellular systems.
  2. It is global system for communicating through mobile phones using GSM as well as in 3G systems.
  3. GPRS data trfer is charged per MB of traffic trferred, where as in circuit switching, data trfer is charged per minute of connection time
  4. GPRS is better packet switching service, as opposed to circuit switching.
  5. 2G cellular systems are combined with GPRS and known as 2.5 G.
  6. Provides moderate speed data trfer by using unused TDMA channels, such as GSM.

SIR is the Signal-to-Interference Ratio - the ratio of the energy in dedicated physical control channel bits to the power density of interference and noise after dispreading.

2G (or 2-G) is short for second-generation wireless telephone technology. Second generation 2G cellular telecom networks were commercially launched on the GSM standard in Finland in 199@Three primary benefits of 2G networks over their predecessors were that phone conversations were digitally encrypted, 2G systems were significantly more efficient on the spectrum allowing for far greater mobile phone penetration levels; and 2G introduced data services for mobile, starting with SMS text messages.

LTE (Long Term Evolution) is the trademarked project name of a high performance air interface for cellular mobile telephony. It is a project of the 3rd Generation Partnership Project (3GPP), operating under a named trademarked by one of the associations within the partnership, the European Telecommunications Standards Institute.

Enhanced Data rates for GSM Evolution (EDGE) (also known as Enhanced GPRS (EGPRS), or IMT Single Carrier (IMT-SC), or Enhanced Data rates for Global Evolution) is a backward-compatible digital mobile phone technology that allows improved data trmission rates, as an extension on top of standard GSM. EDGE is considered a 3G radio technology and is part of ITU's 3G definition.

The service and load determines the NodeB sensitivity; in general, in a no-load condition, the sensitivity is between -115dBm to -125dBm.

For Ericsson, the NodeB sensitivity level is calculated at around: 

CS12.2: -124 dBm ,PS-64: -119 dBm, PS-128: -115 dBm, PS-384: -115 dBm

  1. A wireless technology for Motorola
  2. It has the capabilities of digi-cellular phone, 2 way radio, alphanumeric pager and data modem / fax modem in a single network
  3. Operational bands are 800 MHz, 900 MHz and 1.5 GHz
  4. iDEN is based on TDMA(Time Division Multiple Access) and GSM architecture
  5. For voice compression it uses Motorola's Vector Sum Excited Linear Predictors vocoder
  6. For delivering 64 KBPS over a 25 KHz channel, it uses QAM modulation.
  7. iDEN is designed to serve the mobile user for accessing information quickly without carrying several devices.

4G refers to the fourth generation of cellular wireless standards. It is a successor to 3G and 2G standards. The nomenclature of the generations generally refers to a change in the fundamental nature of the service. The first was the move from analogue (1G) to digital (2G) trmission. This was followed by multi-media support, spread spectrum trmission and at least 200 kbit/s (3G) and now 4G, which refers to all IP packet-switched networks, mobile ultra-broadband (gigabit speed) access and multi-carrier trmission.

Universal Mobile Telecommunications System (UMTS) is one of the third-generation (3G) mobile telecommunications technologies, which is also being developed into a 4G technology. The first deployment of the UMTS is the release99 (R99) architecture. It is specified by 3GPP and is part of the global ITU IMT-2000 standard.

The maximum NodeB output power is usually 20W or 40W, that is, 43dBm or 46dBm.