Cellular Phones as Embedded Systems

7/27/2019 Cellular Phones as Embedded Systems

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Cellular Phones as

Embedded Systems

Liza RodriguezAurelio Morales

EEL 6935 - Embedded Systems

Dept. of Electrical and Computer Engineering

University of Florida


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EEL 6935 Cellular Phones as Embedded Systems 2 of 33

Outline

Introduction

Todays Cellular Phone

Architecture Challenges for Wireless Access Memory, OS, and Power Challenges

Conclusions


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Outline

Introduction



Conclusions


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Cellular Generationso Analog Cellular Technology (1G)

Early 1980s

NMT, AMPS (FDMA) Susceptible to noise and interference. No protection.

o Digital Mobile Communication (2G, 2.5G) Early 1990s

GSM (TDMA), IS-95 (CDMA), IS-136 (D-AMPS, TDMA), PDC (TDMA)

Data services: SMS Digital encryption of conversations. Enhanced privacy.

o Wide Band Mobile Communication (3G, 3.5G) Early 2000s

EDGE (TDMA), CDMA 2000, UMTS (CDMA)

Data transfer rates >= 2 Mbit/s

Data & Voice convergence, Internet access.

o Broadband Mobile Communication (4G) LTE Advanced, IEEE 802.16 (WiMAX)

Data transfer rates >= 100 Mbits/s

Mobile IPTV, Wireless VoIP.


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Evolution of Radio Systems, Mobility, Data Rates

Introduction (cont.)


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Convergence enables people to create, share and

consume digital content, using interoperable devices

Cellular phones evolve from traditional cost-optimizedhandhelds to multifunctional terminals

Cellular phones: key platform for mobile convergence

applications (web browsing, video streaming, etc.)

Digital Convergence

Introduction (cont.)


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Agenda

Introduction



Conclusions


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Extremely complex embedded system

Functional blocks are custom-made for mobility

Chips are either proprietary designs or based

on available chips.

Miniaturization and functionality



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Block diagram of triple-band cellular phone


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Example: Blackberry Bold


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Example: Nokia N95


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Example: Nokia N95


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Example: Nokia N95


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Example: Nokia N95


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Agenda

Introduction



Conclusions


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Development of Cellular phones

Miniaturization

Functionality


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Baseband and RF domains challenges

Challenge Possible solution New Challenges

Baseband ASICs are

limited in performance by

computational power, on-

chip communication and

clock distribution

Decentralized architectures:

small distributed controller

processors running at lower

frequencies

Management of processing

power resources

Baseband flexibility and

support for multiple radio

systems

Use configurable logic,

configurable processors, or

processor generators

Design methodology,

verification and testability

RF Cost and size of

BiCMOS chips

RF on digital CMOS

technology

Substrate-coupling effects,

device models

RF design portability RF on digital CMOS

technologyNew RF circuits and

architectures based on fast

sampling and time-discrete

signal processing needed


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RF challenges: Multiradio

o Wide variety of radio

systems

o Combination of systems at

reasonable cost and sizeo Interference

o Miniaturization challenges

Antennas

Filters


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Outline

Introduction



Conclusions


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Memory Challenge

Total memory requirement is increasing rapidly

Mass Memories interactive games, high

quality video

Large memories are required to support data

downloading and local storage

Supported by external memory cards: MMC or SD

Small Memories processing and small

applications

Memory chips and their interconnections consume large

areas on PCBs and are accessed frequently

New types of NVRAM may challenge memory chips to

provide smaller and more cost effective memory solutions


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NVRAM Alternatives to Flash Memory

Ferroelectric RAM (FeRAM) DRAM cell with ferroelectric dielectric in the storage capacitor

Advantages: low power, faster reads and writes (single word vs. entire

block erase), greater number of write-erase cycles (1016 vs. 106)

Disadvantages: lower storage density, higher cost

Phase Change Memory

Glass cells that become crystalline

or amorphous by cooling

Advantages: faster reads and writes,greater number of write-erase cycles

(108 vs. 106), longer hold times

Disadvantages: temp sensitivity,

no pre-programming


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Application Platform

Mobile internet web browsing, videocalls and high bit rate streaming

Java ME provides flexible user

interfaces, built in network protocols,

multimedia support

Fact: 2.1 Billion mobile phones use

Java platforms

3rd

Party Mobile Applications ifdeveloped in Java, are portable

enough to run on almost all cell phones


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Java Hardware or Software?

Hardware an additional small processor dedicated forrunning Java

Improves performance, minimizes memory requirements

Software becomes dependent on inflexible hardware

implementation

Software Java is run on

baseband processor

Virtual machine Java commands

are interpreted as equivalentmicroprocessor commands -- slow!

Just In Time compiler that would

translate Java classes into processor

instructions --- fast!


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Power Challenge

Recent evolution of communication and applicationfunctions have substantially increased power

consumption

Constant annual growth of 10% in battery capacity has

enabled battery volume shrinkage while having mAhlevel constant

However, when 3G or WLAN communication is run

simultaneously with multimedia applications, power

consumption must be reduced


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Power consumption and Battery Capacity


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Solutions to Power Gap

10% increase in battery capacity will continue forever

Reduce power hungry components:

Antennas Bluetooth, Wi-Fi, RF

Digital displays

Dynamic voltage and frequency scaling (DVFS)

Reconfigurable RF components to reduce the number

of ICs.


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Outline

Introduction



Conclusions


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Cellular phones have come a long way from analog

communication devices to digital mobile computers.

Today, a cellular phone is a paradigm of an embedded

system having highly optimized cost, size, efficiency

and performance.

Challenges in RF circuits, implementation architecture,

memory, and power consumption are still affecting the

development and growth of mobile devices.

New technologies such as decentralized architectures,reconfigurable circuits, advanced memories, and low

power designs will help overcome challenges.

Conclusions


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References

http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1332581

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

http://www.portioresearch.com/resources.htmlhttp://www.phonewreck.com/wiki/index.php?title=BlackBerry_Bold

http://www.phonewreck.com/wiki/index.php?title=Nokia_N95
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1332581http://en.wikipedia.org/wiki/Mobile_phonehttp://www.portioresearch.com/resources.htmlhttp://www.phonewreck.com/wiki/index.php?title=BlackBerry_Boldhttp://www.phonewreck.com/wiki/index.php?title=Nokia_N95http://www.phonewreck.com/wiki/index.php?title=Nokia_N95http://www.phonewreck.com/wiki/index.php?title=BlackBerry_Boldhttp://www.portioresearch.com/resources.htmlhttp://en.wikipedia.org/wiki/Mobile_phonehttp://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1332581


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Cellular Phones as Embedded Systems