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Power Reduction in JTRS Radios with ImpacctPro. Jiwon Hahn , Dexin Li, Qiang Xie, Pai H. Chou, Nader Bagherzadeh, David W. Jensen*, Alan C. Tribble*. UC Irvine, EECS. *Rockwell Collins, Inc. MILCOM. November 2, 2004. Joint Tactical Radio System. Embedded in various military platforms.
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Power Reduction in JTRS Radios with ImpacctPro Jiwon Hahn, Dexin Li, Qiang Xie, Pai H. Chou, Nader Bagherzadeh, David W. Jensen*, Alan C. Tribble* UC Irvine, EECS *Rockwell Collins, Inc MILCOM November 2, 2004
Joint Tactical Radio System Embedded in various military platforms
JTRS • Software Defined Radio (SDR) Technology earmarked for all DoD platforms by 2010 • Multi-band, multi-mode digital radio • Layered open-architecture system • Provides transmission interoperability between different networks such as army, legacy and commercial networks
Outline • Motivation and Goal • Methodology • Tool: ImpacctPro • Simulation Results • Conclusion
Example JTRS Radio • JTRS Step 2B designed by Rockwell Collins • Consumes 9.7 MJ for realistic 10 hour mission! • No power management • Airborne radio form factor
Power Amplifier Transceiver Modem Black Processor Channel 4 (MilStar) Red Processor Red Power Power Amplifier Transceiver Modem Black Processor Channel 3 (ATC) Red Processor Red I/O Power Amplifier Transceiver Modem Black Processor Channel 2 (SATCOM) Red Processor Power Amplifier Transceiver Modem Black Processor Channel 1 (Link 16) Red Processor Black I/O Black Power Time Base / GPS Encryption Domain Controller System Power Challenges for Power Reduction • Complex Architecture • 28 Subsystems • 4 Parallel Channels • 3 Shared resources • Diverse Components • Different power manageability • Power consumption levels • Number of power modes • Mode transition characteristics • Dependencies
Enhancing Power Management Features • Development Cost • Hardware and software modifications • Extensive testing • Evaluation • Not all power modes usable due to system complexity • Analogy of Amdahl’s Law • Need a methodology and tool
Radio Model Simulation Engine Overview Tool (CORBA client) JTRS Status & Measurement (CORBA Server) CORBA Control Commands
(1) (2) ImpacctPro Steps in Methodology • Design Time • System Modeling • Power Optimization • Runtime • Simulation or Measurement • Profiling • Visualization
Architecture Considers dependency in the system level context Captures mode transition overhead Application Parses mission profile to extract scenario parameters and workload eg., 3D location, waveform, SNR, etc eg., messages (task) Proc Modem on on Modem 2W/0.1ms on stb 4W/1us System Modeling Time La.. Lo. Al. Wf 0.11 0.31 -0.34 1000ft Link16 0.20 0.31 -0.34 1000ft Link16 0.21 0.31 -0.34 1000ft Link16 0.41 0.32 -0.34 1000ft Link16 0.51 0.32 -0.34 1001ft Link16 0.64 0.33 -0.34 1001ft Link16 0.71 0.33 -0.34 1001ft Link16 1.11 0.41 -0.34 1001ft Link16 2.11 0.41 -0.34 1001ft Link16
Workload-driven Exploit idle periods Savings rely on input pattern Utilize non-operational power modes Mission-aware Exploit scenario knowledge Adapt to scenario parameters Save active power Power Optimization
Workload-driven Exploit idle periods Savings rely on input pattern Utilize non-operational power modes Mission-aware Exploit scenario knowledge Adapt to scenario parameters Save active power sleep off power on on on off sleep time power saving Power Optimization task Resource Full-ON
Workload-driven Exploit idle periods Savings rely on input pattern Utilize non-operational power modes Mission-aware Exploit scenario knowledge Adapt to scenario parameters Save active power power requirement power saving power time full-on mid-on low-on Power Optimization scenario parameters task Resource Full-ON
Power (dBW) Distance (ft) A A A Time (sec) Example: PA algorithm 1. Get distance from mission profile 2. Translate distance to the min. TX power using communication equation 3. Get timestamped msg. groups from mission profile 4. Assign Active PA modes power high low
1. Get distance from mission profile A I 2. Get timestamped msg. groups from mission profile A I 3. Translate distance to the min. TX power using communication equation A I I I 4. Assign Active PA modes I I I Time (sec) Example: PA algorithm Power (dBW) 5. Assign optimal Idle PA modes power high low
Time (sec) Example: Mission-aware PA algorithm 1. Get distance from mission profile 2. Get timestamped msg. groups from mission profile 3. Translate distance to the min. TX power using communication equation 4. Assign Active PA modes 5. Assign optimal Idle PA modes 6. Output power command sequence for PA power high low
Design Tool: ImpacctPro • Modeling • System description with power models • Optimization • Optimized power control commands • Simulation and Analysis • Hotspot identification • Power profiles of component, channel, system • Multi-granular, interactive GUI • Report generation
Simulation • Simulated mission profiles including existing UCAV mission scenarios with communication activities • Variation of mission length: 30 sec ~ 10 hrs • Variation of message density: 0.1 ~ 24.4 msg/sec • Our technique applied on Rockwell Collins Step-2B prototype
Result 1. Energy Savings Baseline is the system’s power consumption without power management. In the baseline, PA is assumed to be on RX mode (5W) instead of TX mode (372W).
Result 2. Hotspot Identification Before After PA was the largest power consumer before the optimization, which reduces its energy from 45% to below 10%
Result 3. Simulation Speed 90 times faster than real time!
Conclusion • Power Saving • Integrated mission-aware and workload-driven power management to achieve substantial power savings • Experimental results on realistic mission profiles achieved 79%~89% energy reduction • Tool • Captured the new methodology in ImpacctPro for systematic power management policy generation • Provided a powerful design exploration capability that guides the future system specifications
System Level Related Work • Dynamic Voltage Scaling (DVS) • Processor centric • May increase power consumption of other hw resources due to extended execution time • Overhead is often ignored • Dynamic Power Management (DPM) • I/O centric • Devices are treated independently • This work • Captures all devices and their inter-dependencies • Overhead is modeled • Mission aware
PA Transmission Power • Minimum required PA transmission power can be calculated by the following equation: • Equation derived by our assumptions: • Transmission Power depends only on the communication Distance and the operating Frequency