Cellular NetworksPresented by: Ashok Kumar J Supervised by: Tamer Nadeem

CS 752/852 Wireless and Mobile Networking

Introducing 4G

• What is 4G?• Why is 4G so popular?• Is 4G going to be the next world standard?• How fast is 4G growing?• Who currently uses 4G?

US wireless carriers AT&T, Sprint, T-Mobile

and Verizon are already using 4G

Discussion Topics

1G – First Generation Telecommunication System No data transmission at all

2G – Second Generation Telecommunication System Limited data transmission which increased in 2.5G

4G – Fourth Generation Telecommunication SystemCompletely out of the group

4G Underlying TechnologiesDifferent implementations of 4G by different constituents

LTE and WiMAXLTE is being preferred over WIMAX

1G

3G – Third Generation Telecommunication System Fairly High data transmission speeds

2G

3G

4G

Differences

LTE

• Analog Telecommunication Standard• FDMA – Transmission Technique• Hand-off and frequency reuse• No data transmission only voice transmission• First commercially automated cellular network in 1979• Standards: AMPS, NMT, TACS, JTACS, C-450, Radiocom 2000 and RMTI

Drawbacks• Poor security due to lack of encryption• Many different standards being used in

different places• Limitation on the number of calls that

could be made simultaneously

1G – First Generation Mobile Telecommunication

• Purely digital technology• TDMA, GSM, CDMA – operator technologies• Conversations were digitally encrypted• Introduced data services for mobile, starting with SMS• Commercially launched on the GSM standard in Finland in 1991• Circuit-switched data services (HSCSD)• Greatly reduced fraud and discouraged cloned handsets• Operates from 800/900 or 1800/1900 MHz and bandwidth of 2G is 30-200 KHz

Drawbacks• Weak digital signal may not be sufficient

especially in higher frequencies• Increased dropouts• Very slow data transmission

2G – Second Generation Mobile Telecommunication

2.5G Packet-switched domain in addition to the circuit-switched domain GPRS: The first major step in the evolution of GSM networks to 3G GPRS provides data rates of 56-114 kbps CDMA used CDMA2000 1XRTT CDMA data speeds of up to peak 153 kbps and generally up to 60–100 kbps

GPRS Allows 2G and 3G mobile networks to transmit IP packets to the Internet Integrated part of the GSM network switching subsystem GPRS core network in GSM and WCDMA provides

• Mobility management• Session management• Transport for Internet Protocol packet services• Billing based on volume of data and lawful interception

2G Transitional – 2.5G, 2.75G

EDGE (has many versions) Standardized by 3GPP as part of the GSM family Easy upgrade to GPRS and is backward compatible Pre-3G radio technology and is part of ITU's 3G definition Can be used for any packet switched application, like Internet connection Throughput up to 236.8kbps for 4 timeslots, 473.6kbps for 8 Widely used (441 GSM/EDGE networks in 184 countries) Updates are still being released (latest version of EDGE… almost 3G)

2.75G

• Digital broadband packet access• UTMS(WCDMA), CDMA2000 1xEV-DO – operator technologies• Voice telephone, mobile Internet, video calls and mobile TV in a mobile.• Offers greater security than 2G• Supports up to 3.1mbps peak but general speed is 500-700kbps• 3G was relatively slow to be adopted globally• Uses different frequency spectrum than 2G• Operates at 2100MHz and bandwidth of 15-20MHz

Drawbacks• No proper backward compatibility• Need to replace most broadcast towers• No formal definition – carriers used their own

technologies to implement 3G network• Expensive Construction and maintenance

3G – Third Generation Mobile Telecommunication

3G Transitional – 3.5G, 3.75G, 3.9GHSPA(has many versions) Amalgamation of two mobile telephony protocols Improves the performance of existing UTMS protocols Fairly high peak data downlink rates up to 3.6/ 7.2/ 14.4 mbps Fairly high peak data uplink rates up to 5.76mbps General speeds are in between 1-3mbps Reducing the production cost per bit Over 200 operator in more than 80 countries Easy update to existing 3G networks. Preferred over WiMAX, which requires a dedicated network infrastructure

Comparison of Generations 1G, 2G, 3G, 4G.

Generation Definition Throughput Technologies

1G Analog 14.4 kbps (peak) AMPS,NMT,TACS

2G Digital(Narrow band Circuit Data)

9.6/14.4 kbps(peak) TDMA, GSM, CDMA

2G Transitional Packet Data 114/236.8 kbps(peak)20-40 kbps

HSCSD, GPRS, EDGE

3G Digital broadband packet data

3.1 mbps (peak)500-700 kbps

UTMS, CDMA2000 1XRTT

3G Transitional >2mbps 3.6/7.2/14.4 mbps(peak)1-3 mbps

HSPA,CDMA2000 EV-DO

4G Digital broadband packet based

All IP (VOIP)

100 – 300 mbps (peak)3-12 mbps

LTE AdvancedWiMax AdvancedHSPA+

• All IP based secured packet switched network• Voice also transmitted over IP• Supports IPv6• Access schemes – OFDMA, SC-FDMA, MC-CDMA• Supports up to 100mbps downlink and 50mbps uplink.• Using MIMO, speed can be increased.• Technologies – LTE, WiMAX, Wi-Fi metro, HSPA+.• No formal specification – Operators making their own choices.• Verizon, Sprint, ATT, T-Mobile are offering.

4G – Fourth Generation Mobile Telecommunication

4G (Continued)

Ressource: http://4gwirelessjobs.com/lte_wimax.htm

4G (Continued)

Ressource: http://4gwirelessjobs.com/lte_wimax.htm

LTE Advanced (E-UTRAN)• Proposed by 3GPP based on

UMTS/HSPA.• OFDMA for uplink and downlink

• Can be constructed using existing 3G network.

• Backward compatible.• Downlink up to 100mbps and

uplink up to 50mbps.• Natural upgrade to GSM/UMTS

networks, can be using by CDMA networks also.

• Proposed by IEEE based on WiMAX

• OFDMA for downlink and SC-FDMA for uplink.

• Requires completely different network.

• Backward compatible.• Bit rates up to 40mbps.• Can be used by any

network.

WiMAX Advanced

4G Technologies

Resource: www.itechdiary.com/compared-wimax-versus-lte4g.html

Resource: http://1001-tricks.blogspot.com/2010/12/lifehacker-explains-4g-technology.html

• Increased downlink and uplink peak data rates.• Scalable bandwidth and flexible bandwidth.• Improved spectral efficiency• All IP network• A standard’s based interface that can support a multitude of user types.• LTE networks are intended to bridge the functional data exchange gap between

very high data rate fixed wireless Local Area Networks (LAN) and very high mobility cellular networks.

Long Term Evolution - Advanced

Questions?