Integrated Transmitter Architectures for 4G Networks and beyond · 2013-11-07 · Wideband Mobile...

INTEGRATED TRANSMITTER ARCHITECTURES

FOR 4G NETWORKS AND BEYOND

Martin Schleyer, Adel Fatemi | Fachgebiet Mikroelektronik

INTRODUCTIONSYLLABUS / SCHEDULE

Integrated Transmitter Architectures for 4G Networks and beyond | M. Schleyer, A. Fatemi | Session 1

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Syllabus

Course Meeting Times:

– Tuesday, 10:00-12:00 - EN424 (Library)

Schedule and material online at http://www.meis.tu-berlin.de/?id=141359

Course Format:

– approx. four tutorial sessions (check website)

– assignment of topics for individual studies

– final presentations at Jan. 14th

– short paper in IEEE proceeding style - 3 to 4 pages / no deadline (i.e. end of semester)

Objectives:

– Understanding the challenges of LTE/LTE-Advanced TX Architectures

– Efficient MIMO and Carrier Aggregation techniques

– Low-Power concepts for UE terminal devices

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Sessions - Part 1

Date / Time Topic Presenter

November 5th 11:00 Uhr Introduction & Literature

Evolution of Wireless Communication Systems

M. Schleyer

November 12th 10:00 Uhr 3G and 4G Data Standards

from an RF Designer’s Perspective

M. Schleyer

11:00 Uhr TX Architectures and Concepts –

An Introduction

M. Schleyer

November 19th 10:00 Uhr N.N. A. Fatemi

11:00 Uhr N.N. A. Fatemi

November 26th 10:00 Uhr N.N. S. Pinarello

11:00 Uhr N.N. A. Farabegoli

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Literature Recommendations

[3GPP45005] 3GPP: Radio transmission and reception, Standard,

3rd Generation Partnership Project (3GPP), Nr. 45.005, 2008

[Agilent2005] Agilent Technologies: EGPRS Test: Meeting the Challenge of 8PSK Modulation, Online, 2005

[Agilent2005a] Agilent Technologies: 8~Hints for Making and Interpreting EVM Measurements, Online, 2005

[Agilent2002] Agilent Technologies: Understanding GSM/EDGE Transmitter and Receiver Measurements for

Base Transceiver Stations and their Components, Online, 2002

[Dubendorf2003] Dubendorf, V. A.: Wireless Data Technologies: Wiley., 2003

[MacDonald1979] Mac Donald, V.: Advanced Mobile Phone Service: The Cellular Concept. In: The Bell System

Technical Journal 58 (1979), Nr. 1, S. 15--41

[Sauter2011] Sauter, M.: From GSM to LTE: An Introduction to Mobile Networks and Mobile Broadband:

Wiley., 2011

Available at http://www.meis.tu-berlin.de/?id=141359

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FROM MARCONI TOCELLULAR RADIO NETWORKSEVOLUTION OF WIRELESS COMMUNICATION SYSTEMS

Integrated Transmitter Architectures for 4G Networks and beyond | M. Schleyer, A. Fatemi | Session 1

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Wideband Mobile Communication Systems

– Mobile communications systems

revolutionized the way people communicate.

– In rural regions, wireless connections

supersede the classical POTS system!

– From Shannon, we know:

more speed = more bandwidth!

But how did this race for speed start?

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Todays frequency spectrum is allocated to manifold

stake holders [NIST2011]

First Steps in Wireless Communications

Guglielmo Marconi’s patent application from June 1896:

“Improvements in Transmitting Electrical impulses and

Signals, and in Apparatus therefor.“ [Marconi1896]

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– First experiments on wireless telegraphy

performed by Alexander Popow in 1896

– Marconi‘s patent, filed June 2nd 1896, uses

practially similar receiving techniques

– In the early 1900‘s, spark-gap transmitter

allowed wireless trans-atlantic telegraphy

– Publically available transatlantic telegraphy

services started at 1907

– Marconi‘s wireless telegraphy system is

often considered as the world‘s

first wireless communcation system

Spark-gap transmitters

The principle of spark-gap transmitters is based on Heinrich

Hertz‘s experimemts to prove Maxwell equations:

– Two conducting electrodes are separated by a gap

– If a sufficiently high voltage is applied

a spark bridges the gap

– An LC tank is attached to the gap and oscillates

A damped oscillation with high bandwidth is transmitted

Maxwell’s Equations [Jha2013]

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Spark-gap transmitter circuit

[Lindner2007]

a) Marconi Wave

b) Braun Oscillator

c) Quenched spark transmitter wave

d) Undamped oscillation [Dowsett1920]

Radio Frequency Alternator Transmitters

Spark-gap transmitters allowed telegraphy, but had very

high bandwidth for low transmissision capacity

– Reginald Fessenden started to develop first continuous-

wave transmitter for General Electrics

– Pure sinewave = small bandwidth, at considerably less

power consumption

– First audio transmission performed at Christmas 1906

AM modulation scheme instead of pure BPSK (= On-Off)

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Reginald Hessenden

[Harpers1903]

Basics of AM demodulation / detection [Poole2013]

From Broadcast to Cellular Communication - The A Net

In the early 1960‘s, the A network started commercial

operations in (Western) Germany

– First experiments with mobile communications in

Germany with phone in train service in 1926

– The actual A Network used manual switch boards,

no cell roaming available

– UHF frequency operation at 156-174 MHz

– At 1971, the network had 10.784 subscribers [Kedaj1991]

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Te-Ka-De A-Net “Handset” B72Upper part: Control Unit

Lower Part: Transceiver (in car booth)

[FA2007]

A-Net Logo A-Net - Subscribers and Channels[OeBL2013][OeBL2013]

One Step Forwared - The B-Network

The B-Network used FM modulation and supported

automated switch board

– Operation started in 1972, the B-Net was online until 1994

– FM transmission = more robust to fading and diversity

– Channel separation of 20kHz (bandwidth 14 kHz)

(GSM: 200kHz channel distance)

– Still no cell roaming - caller had to know callees location

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Bosch OF-4 HandsetB-Net Logo B-Net Coverage in 1990[OeBL2013] [OeBL2013]

[OeBL2013]

The Cellular Approach - AMPS Network

To extend capacity and effiency, Bell Labs proposed the

Advanced Mobile Phone System. It introduced the

cellular concepts on which all modern standards rely!

Frequency Reuse: A hexagonal pattern is applied to the

coverage area - each requency can be used multiple

times in the system

Locating: The system is able to locate the user in any cell

of the network. No a-priori information needed

Hand Off: calls are moved with the user, if he changes his

location and the neighbouring cell has better SNR

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[MacDonald1979]

Cellular Approach /

Frequency Reuse [MacDonald1979]

Analog, but state of the art - The C Network

In 1985, the C net launched using the cellular approach.

Baseband signals were still analog, but control systems

are fully digitalized.

– Eight home location registers managed user location

– Subscriber cards are used - predecessor of SIM cards

C-Net Air Interface:

– In total 222 (1991: 287) individual channels

– Analog modulation scheme allowed very high spectral

efficiency (almost no redundancy added)

– Hybrid TDMA operation (control channel: 5,28 kbit/s):

12.5 ms audio (compressed by 10%)

+ 1.25ms digital control information

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BOSCH Handy C9

C Net

Logo

C Net

Subscriber

card[OeBL2013]

[OeBL2013]

[OeBL2013]

THE 3GPP ECO SYSTEMEVOLUTION OF WIRELESS COMMUNICATION SYSTEMS

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GSM Standard - First international 2G Network

In the late 1980‘s, first-generation networks where available in

many countries - but no roaming capablities available…

– In 1982, the european telecommunication authorities

(CEPT) establish the Groupe Spécial Mobile - GSM

– Goal: an european standard for a digital cellular network

– In 1990, the first specifications are freezed and serve as

foundation for first commercial applications

– In Germany, Deutsche Telekom and Mannesmann start

commercial operations on July,1st 1992.

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Nokia 1011 [Smith2007]

GSM Logo and Coverage

[GT2010]

GSM System Architecture

GSM is based on circuit switched architecture,

as in public phone networks

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GSM System Architecture [Dubendorf2003]

MS Mobile StationUser Terminal (Cell Phone, Data Card, …)

BSS Base Station SubsystemMin. one BSC and several BTSs

BTS Base Transceiver StationRadio frontend on operator side

BSC Base Station ControllerControls several cells (paging, handover…)

NSS Network SubsystemLocation register, authentication, switching

OMC Operation & Maintenance CenterManagement unit on operator side

[Dubendorf2003]

GSM Radio Access Network (RAN)

Band UL [MHz] DL [MHz]

GSM 900 880 - 915 925 - 960

GSM 1800 1710 - 1785 1805 - 1880

GSM 1900 1850 - 1910 1930 - 1990

GSM 850 824 - 849 869 - 894

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GSM Radio Access Network [Dubendorf2003]GSM Frequency Allocation [Sauter2011]

FDMA: Frequency Division Multiplex Access

duplex link, parallel channels

TDMA: Time Division Multiplex Access

channel is divided in time slots (bursts),

up to eight subscribers per channel

FHSS: Frequency Hopping Spread Spectrum

MT is changing channels on pseudo-random

basis to avoid interference & fading

GSM Signal Properties

GSM uses a Frequency Shift Keying (FSK) scheme with a

Minimum Shift (MSK). Additionally, a Gaussian filter is

applied, the so called Gaussian Minimum Shift Keying

– Continuous phase digital frequency modulation with

modulation index h=1/2

– Characterized by the value of BT, where T = bit durationand

B = 3dB Bandwidth of the shaping filter, BT = 0.3 for GSM

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GMSK Spectral Density [MXCom1998]

GSM Baseband Signals

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Properties of GSM Signals – RF Designer‘s View

The GMSK scheme used for GSM is a constant envelope modulated signal

– The amplitude of the carrier is constant, regardless of the signal information

Only the phase contains information

Advantages of constant envelope:

Power efficient – power amplifiers can be non-linear, e.g. high efficient switching PA

low out-of-band radiation of the order of -60dB to -70 dB

RF requirements are less challenging – most power contained close to carrier

High immunity against random FM noise and Rayleigh fading

Drawbacks of constant envelope:

More bandwidth compared to linear modulation techniques

Baseband processing is more complex (…but no issue anymore in the 2000‘s…)

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GSM Transmitter Characteristics

The 3GPP TS 45.005 specifications define the typical

requirements for GSM handset transmitters.

– Spectral Mask: Limit of spectral regrowth, avoid interference

with neighbouring channel

– Power Level Control: Reduce power level according to BTS

distance – avoid receiver desensitizing

– Modulation Accuracy: RMS phase error below 5° with max.

peak deviation of

30° during the burst

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GSM 900 DCS 1800

1 30 dBm

2 39 dBm 24 dBm

3 37 dBm 36 dBm

4 33 dBm

5 29 dBm…

15 13 dBm 0 dBm…

19 5 dBm[Agilent2002]

[3GPP45005]

Sources and Literature

[3GPP45005] 3GPP: Radio transmission and reception,

Bericht, 3rd Generation Partnership Project

(3GPP), Nr. 45.005, 2008

[Agilent2002] Agilent Technologies, I.: Understanding

GSM/EDGE Transmitter and Receiver

Measurements for Base Transceiver Stations

and their Components, Online, 2002

[Dowsett1920] Dowsett, H.: Wireless Telegraphy and

Telephony. First Principles, Present Practice,

and Testing: The Wireless Press, Ltd., 1920

[Dubendorf2003] Dubendorf, V. A.: Wireless Data

Technologies: Wiley., 2003

[FA2007] Aachen, F.: Te-Ka-De B72 Funktelefon für A-

Netz, Online, 2007

[GT2010] Telesat, G.: Satellite Phones vs. Cell Phones,

Online, 2010

[Harpers1903] Magazine, H. W.: American Wireless

Telegraphy, 1903, S. 298

[OeBL2013] Hessberger, S.: ÖbL - Öffentlicher

beweglicher Landfunk, Online,

[Jha2013] Jha, A.: What are Maxwell's Equations?,

Online, 2013

[Lindner2007] Lindner, M.: Historie der Funktechnik, Online,

2007

[MacDonald1979] Mac Donald, V.: Advanced Mobile Phone

Service: The Cellular Concept. In: The Bell

System Technical Journal 58 (1979), Nr. 1, S.

15--41

[Marconi1896] Marconi, G.: Improvements in Transmitting

Electrical impulses and Signals, and in

Apparatus therefor, Nr. 12,039, 1897

[MXCom1998] MX Com, I.: Practical GMSK Data

Transmission, 1998

[Poole2013] Poole, I.: Radio receiver amplitude

modulation AM demodulation, Online, 2013

[Sauter2011] Sauter, M.: From GSM to LTE: An

Introduction to Mobile Networks and Mobile

Broadband: Wiley., 2011

[Smith2007] Smith, T.: 15 years ago: the first mass-

produced GSM phone, Online, 2007

[NIST2011] Telecommunications, N. & Administration, I.:

United States Frequency Allocations: The

Radio Spectrum Chart, Online, 2011

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