From GSM to LTE

Martin Sauter - www.wirelessmoves.com - From GSM to LTE - Medienforum NRW - June 2011 1

Medienforum NRW 2011

From GSM to LTE – An Introduction

Martin Sauter


Who Am I• (Wireless) Network Researcher and Blogger• Book Author• Project Manager working for a Mobile Network

Operator


Technology Overview: GSM(First Networks 1992/93)


GSM Characteristics• Originally designed for telephony• 200 kHz (0.2 MHz) carriers (channels)• 8 timeslots per channel = 8 phone calls• 3 sectors (120°) per base station is typical• Several carriers per sector is typical• Max range: Up to ~30 km• Typical range: 500m in cities for capacity

reasons


Typical Base Station Antennas

Picture: Martin Sauter


Technology Overview: UMTS(First Networks 2002/2003)


UMTS / HSPA Network Architecture

Source: Beyond 3G

, Bringing Netw

orks, Terminals and

The bread and butter service!


GSM / UMTS / LTE BTS'es Today

Pictures: Martin Sauter


HSPA today• Frequency Bands (→ http://tinyurl.com/4pdr3o)

• Speeds, Always-On, Keep-Alive Signaling• Activity States (DCH, Cell-FACH, Cell-PCH, URA-PCH, Idle →

http://tinyurl.com/2w5c9zj)

• Latency• Power Consumption, Fast Dormancy• → Impact on Services• → Impact on Network

(Further Reading: http://tinyurl.com/2e6dxkt)

http://tinyurl.com/4pdr3o

http://tinyurl.com/2w5c9zj

http://tinyurl.com/2e6dxkt


HSPA+: Higher Speeds And MoreService Benefits• New features beyond higher speeds and their

impact on services, e.g.:• Lower latency• Less power consumption in idle mode• Faster and fewer state switches

Further background: http://en.wikipedia.org/wiki/Hsdpa

http://en.wikipedia.org/wiki/Hsdpa


Higher Speeds But Not EverywhereEricsson Review article shows maximum speed depending on location.

http://tinyurl.com/dk6c2p (not included due to copyright reasons but available via this link, see Figure 2)

http://tinyurl.com/dk6c2p


The Backhaul Impact on Services• For both HSPA and LTE, the legacy backhaul

architecture based on x * 2 Mbit/s E-1 links is by far not sufficient anymore and far too expensive.

• Alternatives:• Fiber – Very fast but expensive rollout• VDSL – In combination with VDSL + fiber network

deployment for super high speeds for homes.• Microwave Ethernet


Technology Overview: LTE(First Networks 2010/11)


LTE Network Overview

Source: M

artin Sauter, From

GS

M to LTE

The bread and butter service is missing!


OFDMA – What is That?

OFDMA = Orthogonal FrequencyDivision Multiple Access


Bandwidth: How Much and Where?• 1.25 – 20 MHz: Impacts max. possible speed• 10 MHz in 800 MHz Digital Dividend per Network• 15-20 MHz Channels in 1800 and 2600 MHz• Lots of bands globally, even locally, everything

between 700 and 3600 MHz. Big issue! • → The „hedgehog phone“ - is it realistic?

LTE Bands - For further reading: http://tinyurl.com/3ywx2vs

http://tinyurl.com/3ywx2vs


LTE = IP Services only• Pros:

• Simplified Network Infrastructure• Less Latency• Less Complexity

• Cons:• Complex integration of voice services with the

ability to hand-over to GSM or UMTS when leaving the coverage area.


GSM, HSPA and LTE side by side• GSM for voice centric devices, maximum

coverage and international voice roamers.• UMTS (HSPA) for mobile devices with a strong

voice integration (smartphones) and high speed data (3G USB dongles).

• LTE to provide high speed Internet access in rural areas (800 MHz), indoor coverage (cities) and high capacity (cities, 1800 and 2600 MHz). (LTE USB sticks, pads, notebooks, etc.).


When Will GSM be Switched Off?• NTT DoCoMo to switch-off 2G in 2011 – special

case (http://tinyurl.com/2uprcyx)

• GSM will remain strong well over this decade and beyond. Reasons: 3G still not ubiquitous, equipment refreshes, roaming, new entrants, new markets, handset prices. Thoughts from back in 2007: http://tinyurl.com/34t7pfe)

• Phaseout Architectures (http://tinyurl.com/375v5yd)

• Virtual GSM (http://tinyurl.com/2vx939b)

http://tinyurl.com/2uprcyx

http://tinyurl.com/34t7pfe

http://tinyurl.com/375v5yd

http://tinyurl.com/2vx939b


Picture by Fabian Schustek

Thank You!

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From GSM to LTE