Fourth Generation (4G)Wireless Systems

Jeremy Mayeres

Topics

Cellphones 1G 2G 3G 4G/IMT-Advanced LTE WiMAX 4G Today Future of 4G Social/Ethical considerations

Cellphones

Radio telephony existed long before cell phones became popular

1947 – Ring and Young working at Bell Labs develop idea of using “hexagonal cells”

1973 – First cell phone call – Martin Cooper of Motorola

1G

Analog system Advanced Mobile Phone System

(AMPS) in the US Frequency Division Multiple Access

(FDMA) – Different frequency for each conversation

Issues Listen in with a scanner Spoofing

2G

Digital Time Division Multiple Access (TDMA)

GSM (Global System for Mobile Communications)

D-AMPS (Digital AMPS, superseded by GSM)

iDEN (Integrated Digital Enchanced Network)

Code Division Multiple Access (CDMA) IS-95/cdmaOne

2.5G and 2.75G 2G with always-on data General Packet Radio Service (GPRS)

2.5G for GSM Maxed at about 115 Kbps

1xRTT 2.5G for CDMA Maxed at about 153 Kbps

Enhanced Data rates for GSM Evolution (EDGE) 2.75G Speeds up to 1 Mbps

3G

International Telecommunications Union (ITU) International Mobile Telecommunications-2000 (IMT-2000)

Requires minimum speed of 200 Kbps

3rd Generation Partnership Project (3GPP) – 3G Upgrade for GSM

3GPP2 – 3G Upgrade for CDMA

3G - UMTS

Universal Mobile Telecommunications System (UMTS) by 3GPP

Uses W-CDMA (Wideband CDMA) Handles voice and data Data speeds about 384 Kbps (R99)

to 2 Mbps More on this later…

3G – CDMA2000

3GPP2 Group Backwards compatible with

cdmaOne 1xEV-DO (or just EV-DO) Evolution-

Data Optimized Rev. 0: Max speed of about 2.4 Mbps

download, 153 Kbps upload Rev. A: Max speed of about 3.1 Mbps

download, 1.8 Mbps upload

4G IMT-Advanced by ITU

Global use High-quality services User-friendly High speeds: 1 Gbps stationary, 100 Mbps mobile Spectrum efficiency IP packet-switched network

LTE (Long Term Evolution) IEEE 802.16 “WiMAX” (Worldwide

Interoperability for Microwave Access)

OFDMA

Orthogonal Frequency-Division Multiple Access

Split channel into sub-carriers User is assigned multiple sub-

carriers: Closer to base gets more sub-carriers

(more bandwidth) Further away, get less sub-carriers, but

use more power OFDM also used in 802.11a/g/n

MIMO

Multiple In – Multiple Out

Diversity Avoid fading due to

multipath interference, shadows

Spatial Multiplexing Use multiple channels

to get higher data rates

LTE

3GPP Verizon, MetroPCS, AT&T, and Sprint Upgrades UMTS Uses MIMO, OFDMA IP-based 700 MHz Band Speed: 100 Mbps download, 50 Mbps

upload

WiMAX

IEEE 802.16e-2005 Scalable OFDMA (SOFDMA) – Scales

the Fast Fourier Transform (FFT) size for different bandwidths

Primarily uses 2.5 GHz band in the US (Clear/Sprint)

Use as backhaul Closer to WiFi Speeds up to 40 Mbps

Not technically 4G

WiMAX and LTE in today’s networks do not meet the IMT-Advanced criteria

Every major wireless 4G network fails to meet IMT-Advanced criteria

ITU accepts WiMAX and LTE as “Pre-4G”

Can also be called 3.9G Networks still calling it 4G

HSDPA, HSUPA, HSPA+

“High Speed Packet Access,” part of 3GPP

D – Downlink, U – Uplink HSDPA – 7.2 Mbps, HSUPA – 1.9 Mbps HSPA+ (Evolved HSPA)

84 Mbps download, 22 Mbps upload MIMO All-IP Option

Still part of 3G, UMTS T-Mobile/AT&T calling it 4G

So what satisfies IMT-Advanced? LTE-Advanced (3GPP) and

WirelessMAN-Advanced (IEEE 802.16m)

Not yet available Will satisfy the 1 Gbps download

speed requirement What will this be called?

Social/Ethical considerations Is 4G just a marketing term? Bringing broadband to everyone Wireless capacity and Net Neutrality

Sources

IMT-Advanced - Objective and Challenges by K. Jay Miyahara

An Overview of Next-Generation Mobile WiMAX Technology by Sassan Ahmadi

On the Way towards Fourth-Generation Mobile: 3GPP LTE and LTE-Advanced by David Martin-Sacristian, et al.

History of Mobile Telephones (Wikipedia and related articles)