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Cellular Phones as Embedded Systems

Cellular Phones as Embedded Systems. EEL 6935 - Embedded Systems Dept. of Electrical and Computer Engineering University of Florida. Liza Rodriguez Aurelio Morales. Outline Introduction Today’s Cellular Phone Architecture Challenges for Wireless Access Memory , OS, and Power Challenges

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Cellular Phones as Embedded Systems

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

  2. Outline • Introduction • Today’sCellularPhone • ArchitectureChallengesforWireless Access • Memory, OS, and PowerChallenges • Conclusions

  3. Outline • Introduction • Today’sCellularPhone • ArchitectureChallengesforWireless Access • Memory, OS, and PowerChallenges • Conclusions

  4. Cellular Generations • Analog Cellular Technology (1G) • Early 1980’s • NMT, AMPS (FDMA) • Susceptible to noise and interference. No protection. • 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. • 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. • Broadband Mobile Communication (4G) • LTE Advanced, IEEE 802.16 (WiMAX) • Data transfer rates >= 100 Mbits/s • Mobile IPTV, Wireless VoIP.

  5. Introduction (cont.) Evolution of Radio Systems, Mobility, Data Rates

  6. Introduction (cont.) Digital Convergence • 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.)

  7. Agenda • Introduction • Today’sCellularPhone • ArchitectureChallengesforWireless Access • Memory, OS, and PowerChallenges • Conclusions

  8. Today’s Cellular Phone • Extremely complex embedded system • Functional blocks are custom-made for mobility • Chips are either proprietary designs or based on available chips. • Miniaturization and functionality

  9. Block diagram of triple-band cellular phone

  10. Example: Blackberry Bold

  11. Example: Blackberry Bold

  12. Example: Blackberry Bold

  13. Example: Blackberry Bold

  14. Example: Nokia N95

  15. Example: Nokia N95

  16. Example: Nokia N95

  17. Example: Nokia N95

  18. Agenda • Introduction • Today’sCellularPhone • ArchitectureChallengesforWireless Access • Memory, OS, and PowerChallenges • Conclusions

  19. Development of Cellular phones • Miniaturization • Functionality

  20. Baseband and RF domains challenges

  21. RF challenges: Multiradio • Wide variety of radio systems • Combination of systems at reasonable cost and size • Interference • Miniaturization challenges • Antennas • Filters

  22. Outline • Introduction • Today’sCellularPhone • ArchitectureChallengesforWireless Access • Memory, OS, and PowerChallenges • Conclusions

  23. 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

  24. 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

  25. Application 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

  26. 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!

  27. Power 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

  28. Power consumption and Battery Capacity

  29. 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.

  30. Outline • Introduction • Today’sCellularPhone • ArchitectureChallengesforWireless Access • Memory, OS, and PowerChallenges • Conclusions

  31. Conclusions • 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.

  32. References • 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

  33. Questions?

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