On Using Battery State On Using Battery State for Medium Access Control for Medium Access Control in Ad hoc Wireless in Ad hoc Wireless Networks - “BAMAC” Networks - “BAMAC” S. Jayashree, B. S. Manoj, C. Siva Ram Murthy S. Jayashree, B. S. Manoj, C. Siva Ram Murthy Department of Computer Science and Department of Computer Science and Engineering, Engineering, Indian Institute of Technology Madras, Indian Institute of Technology Madras, India. India.
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On Using Battery State for Medium Access Control in Ad hoc Wireless Networks - “BAMAC” S. Jayashree, B. S. Manoj, C. Siva Ram Murthy Department of Computer.
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On Using Battery State for Medium On Using Battery State for Medium Access Control in Ad hoc Wireless Access Control in Ad hoc Wireless
Networks - “BAMAC”Networks - “BAMAC”
S. Jayashree, B. S. Manoj, C. Siva Ram MurthyS. Jayashree, B. S. Manoj, C. Siva Ram Murthy
Department of Computer Science and Engineering,Department of Computer Science and Engineering,
Indian Institute of Technology Madras,Indian Institute of Technology Madras,
India.India.
Energy Management in Ad hoc Energy Management in Ad hoc Wireless NetworksWireless Networks
Energy management:Energy management: Process of managing energy resources by Process of managing energy resources by means of controlling the battery discharge, adjusting transmission means of controlling the battery discharge, adjusting transmission power, and scheduling power sources, so as to increase the lifetime of power, and scheduling power sources, so as to increase the lifetime of an Ad hoc wireless networkan Ad hoc wireless network
Why energy management?Why energy management? Fig
Limited energy reserveLimited energy reserve
Difficulties in replacing the batteriesDifficulties in replacing the batteries
Lack of central coordinationLack of central coordination – – relay nodes?relay nodes?
Constraints on the batteryConstraints on the battery – – weight-capacityweight-capacity relationshiprelationship
Selection of optimal transmission powerSelection of optimal transmission power
Channel utilization for CDMA based systemChannel utilization for CDMA based system
Battery-related TermsBattery-related Terms
What is a battery ?What is a battery ? Characterizing batteriesCharacterizing batteries
• Voltages (open circuit, operating, and cut-off)Voltages (open circuit, operating, and cut-off)
• Capacities - Rate capacity effect and Recovery capacity Capacities - Rate capacity effect and Recovery capacity effecteffect
o Theoretical (T)Theoretical (T)
o Nominal/standard (N) Nominal/standard (N)
o ActualActual
BAMAC(BAMAC(kk) MAC Protocol) MAC Protocol Inspiration!Inspiration! Battery-aware MAC protocol (BAMAC(Battery-aware MAC protocol (BAMAC(kk))))
• Main Idea – MAC + Battery informationMain Idea – MAC + Battery information• Exploiting recovery state of the batteriesExploiting recovery state of the batteries• Uniform discharge of the batteriesUniform discharge of the batteries• Nodes are scheduled in a near round-robin mannerNodes are scheduled in a near round-robin manner• MAC protocol – “The higher the remaining battery capacity, the MAC protocol – “The higher the remaining battery capacity, the
lower the back-off period.”lower the back-off period.” Discrete-time Markov chain analysis of battery lifetimeDiscrete-time Markov chain analysis of battery lifetime Comparative study of IEEE 802.11 and DWOP with Comparative study of IEEE 802.11 and DWOP with
BAMAC and Simulation Vs. Theoretical AnalysisBAMAC and Simulation Vs. Theoretical Analysis Analysis of the factor ‘Analysis of the factor ‘kk’’
Illustration of Battery TableIllustration of Battery Table
Back-off CalculationBack-off Calculation
CwCwminmin – Minimum size of the contention window– Minimum size of the contention window
rankrank – – Position of that entry in the batteryPosition of that entry in the battery TTSIFSSIFS+T+TDIFSDIFS – SIFS and DIFS duration as in IEEE 802.11 – SIFS and DIFS duration as in IEEE 802.11
TTtt – Successful packet transmission time, including RTS- – Successful packet transmission time, including RTS-
CTS-Data-ACKCTS-Data-ACK x x – Number of transmission attempts made for a packet– Number of transmission attempts made for a packet Uniform(Uniform(i,ji,j) – random number distributed uniformly ) – random number distributed uniformly
between between i i and and jj n - n - Number of neighborsNumber of neighbors
Illustration of BAMACIllustration of BAMAC
T- Theoretical capacity
N- Nominal capacity
t- Time of transmission
Modeling the Batteries Using Modeling the Batteries Using Discrete-Time Markov Chain With Discrete-Time Markov Chain With
TT - Initial theoretical capacity ; - Initial theoretical capacity ; NN - Initial nominal capacity- Initial nominal capacity TTii - Theoretical capacity at time unit - Theoretical capacity at time unit I; I; NNii - Nominal capacity at time unit - Nominal capacity at time unit i i
TxTx -- Transmission state ;Transmission state ; RxRx -- Recovery stateRecovery state RRNi,TiNi,Ti - Probability to recover one charge unit - Probability to recover one charge unit
Illustration of battery discharge Illustration of battery discharge of nodes using BAMAC(k)of nodes using BAMAC(k)
Average discharge time = Average discharge time = k*Tk*Ttt
Average recovery time = Average recovery time = n*k*Tn*k*Ttt
n*kn*kk
PM
Final Markov Model Representing Final Markov Model Representing Battery BehaviorBattery Behavior
jiQQ ,
Steps to Calculate Time Duration of the Markov Model to Remain in Steps to Calculate Time Duration of the Markov Model to Remain in Transient StatesTransient States
Transmission – Transmission – 22; Reception –; Reception – 1 1 ; idle – ; idle – 0 0; Listening -; Listening - 0 0 A small battery to power up during idle modeA small battery to power up during idle mode Existence of SBS – state of the batteryExistence of SBS – state of the battery
Simulation areaSimulation area 2000m x 2000m2000m x 2000m
Results for BAMAC(Results for BAMAC(kk))Number of packets transmitted Remaining battery charge
Infinite theoretical capacity
……ContdContd
Average throughput Standard deviation of throughput
Remaining nominal capacity Nominal capacity spent
……ContdContd
Packets transmitted for 1>k>20 Packets transmitted for 1>k>250
Simulation results
Theoretical results
……ContdContd
Throughput for 1>k>20 Throughput for 1>k>250
Conclusion and Future PerspectiveConclusion and Future Perspective What is our contribution?What is our contribution? BAMAC(BAMAC(kk) – Battery Aware MAC protocol) – Battery Aware MAC protocol Modeling of batteries using Discrete-time Markov chain analysis: Battery Modeling of batteries using Discrete-time Markov chain analysis: Battery
Lifetime CalculationLifetime Calculation Analysis of the factor “Analysis of the factor “k”k” Performance AnalysisPerformance Analysis Future perspectiveFuture perspective Finding optimalFinding optimal K K ValueValue Relaxing the basic assumptionsRelaxing the basic assumptions
Sleep mode instead of idle mode!Sleep mode instead of idle mode! Absence of an additional small batteryAbsence of an additional small battery
Heterogeneous battery technologiesHeterogeneous battery technologies Presence of real-time data trafficPresence of real-time data traffic Generalized Markov modelGeneralized Markov model Develop a generalized tool for calculating battery life time for all MAC Develop a generalized tool for calculating battery life time for all MAC
protocolsprotocols
THANK YOUTHANK YOU
IIT MadrasIIT Madras
IBM-IRL IndiaIBM-IRL India
DST Delhi, IndiaDST Delhi, India
Increasing Gap Between Power Increasing Gap Between Power Requirement And AvailabilityRequirement And Availability
K. Lahiri, A. Ragunathan, S. Dey, and D. Panigrahi, “ Battery-DrivenSystem K. Lahiri, A. Ragunathan, S. Dey, and D. Panigrahi, “ Battery-DrivenSystem Design: A New Frontier in low-Power Design,” Design: A New Frontier in low-Power Design,” Proceedings of ASP-DAC/VLSI Proceedings of ASP-DAC/VLSI Design 2002.Design 2002.