Cellular Phones as Embedded Systems Liza Rodriguez Aurelio Morales EEL 6935 - Embedded Systems Dept. of Electrical and Computer Engineering University.

Cellular Phones as Embedded Systems

Liza RodriguezAurelio Morales

EEL 6935 - Embedded SystemsDept. of Electrical and Computer

EngineeringUniversity of Florida

EEL 6935 Cellular Phones as Embedded Systems 2 of 33

OutlineOutline

• IntroductionIntroduction• Today’s Cellular PhoneToday’s Cellular Phone• Architecture Challenges for Wireless AccessArchitecture Challenges for Wireless Access• Memory, OS, and Power ChallengesMemory, OS, and Power Challenges• ConclusionsConclusions


OutlineOutline



Cellular GenerationsCellular Generationso Analog Cellular Technology (1G)

Early 1980’s NMT, AMPS (FDMA) Susceptible to noise and interference. No protection.

o Digital Mobile Communication (2G, 2.5G) Early 1990’s 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 2000’s 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.


Evolution of Radio Systems, Mobility, Data RatesEvolution of Radio Systems, Mobility, Data Rates

Introduction (cont.)Introduction (cont.)


• Convergence enables people to create, share and consume digital content, using interoperable devices

• Cellular phones evolve from traditional cost-optimized handhelds to multifunctional terminals

• Cellular phones: key platform for mobile convergence applications (web browsing, video streaming, etc.)

Digital ConvergenceDigital Convergence

Introduction (cont.)Introduction (cont.)


AgendaAgenda



• Extremely complex embedded system

• Functional blocks are custom-made for mobility

• Chips are either proprietary designs or based on available chips.

• Miniaturization and functionality

Today’s Cellular PhoneToday’s Cellular Phone


Block diagram of triple-band cellular phoneBlock diagram of triple-band cellular phone


Example: Blackberry BoldExample: Blackberry Bold








Example: Nokia N95Example: Nokia N95








AgendaAgenda



Development of Cellular phones Development of Cellular phones

• Miniaturization• Functionality


Baseband and RF domains challengesBaseband 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 technology

New RF circuits and architectures based on fast sampling and time-discrete signal processing needed


RF challenges: MultiradioRF challenges: Multiradio

o Wide variety of radio systems

o Combination of systems at reasonable cost and size

o Interferenceo Miniaturization challenges

Antennas Filters


OutlineOutline



Memory ChallengeMemory 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


NVRAM – Alternatives to Flash MemoryNVRAM – 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


Application PlatformApplication Platform

• Mobile internet – web browsing, video calls 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 – if developed in Java, are portable enough to run on almost all cell phones


Java – Hardware or Software?Java – Hardware or Software?

• Hardware – an additional small processor dedicated for running 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 equivalent microprocessor commands -- slow!

• Just In Time – compiler that would translate Java classes into processor instructions --- fast!


Power ChallengePower Challenge

• Recent evolution of communication and application functions have substantially increased power consumption

• Constant annual growth of 10% in battery capacity has enabled battery volume shrinkage while having mAh level constant

• However, when 3G or WLAN communication is run simultaneously with multimedia applications, power consumption must be reduced


Power consumption and Battery CapacityPower consumption and Battery Capacity


Solutions to Power GapSolutions 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.


OutlineOutline



• 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.

ConclusionsConclusions


ReferencesReferences

• http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1332581 • http://en.wikipedia.org/wiki/Mobile_phone • http://www.portioresearch.com/resources.html • http://www.phonewreck.com/wiki/index.php?title=BlackBerry_Bold • http://www.phonewreck.com/wiki/index.php?title=Nokia_N95


Questions?Questions?

Cellular Phones as Embedded Systems Liza Rodriguez Aurelio Morales EEL 6935 - Embedded Systems Dept. of Electrical and Computer Engineering University.

Documents

band cellular phone

power challenges memory

blackberry bold slide

wireless access memory

nokia n95 slide

evolution of radio systems

data rates introduction

internet access