energy and spatial reuse efficient network-wide real-time data broadcasting in mobile ad hoc...
TRANSCRIPT
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Energy and Spatial Reuse Efficient Network-Wide Real-Time
Data Broadcastingin Mobile Ad Hoc NetworksB. Tavli and W. B. Heinzelman
Julián [email protected]
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Overview
• Introduction
• Background
• MH-TRACE
• NB-TRACE
• Simulation
• Conclusions
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Introduction
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Network-Wide Real-TimeData Broadcasting
• Military networks– Broadcast– QoS– Can not restrict to single-hop
• Energy efficiency, efficient spatial reuse and QoS are mandatory– No architecture proposed so far addressing all them– Network-wide Broadcasting through Time Reservation
using Adaptive Control for Energy efficiency (NB-TRACE)
– Based on MH-TRACE
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Background
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Energy Dissipation
• Different Categories– Transmit mode– Receive mode– Idle mode– Carrier sense mode– Sleep mode
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Energy Dissipation (II)
• How to Achieve it?– Unnecessary carrier sensing– Idle energy dissipation– Overhear irrelevant packets– Transmit energy dissipation– Reduce overhead
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Energy Dissipation (III)
• Before– IEEE 802.11 supports ATIM
• Ad Hoc Traffic Indication Message• Reduces idle time but doesn’t address overhear• Focused on unicast traffic
– SMAC• Periodically shuts off radios to reduce idle time• With low traffic outperforms IEEE 802.11
• TSMAC and RSMAC
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Energy Dissipation (and IV)
• About overhearing– Information Summarization (IS) packet
• RTS/CTS packets on top of IEEE 802.11– Power Aware Multiaccess protocol with Signaling for Ad
Hoc Networks (PAMAS)
• Redundant IS packet? Go sleep!
• Delay, throughput and transmit dissipation– There is an optimum transmit radio DOP
• Beyond DOP multi-hop outperforms single-hop• Great for constant transmit range radios
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Efficient Spatial Reuse
• # retransmissions required for a packet to be received by every node
• Algorithms– Non-coordinated– Fully coordinated
• Create a Minimum Connected Dominating Set
– Partially coordinated• Create a MCDS, almost
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Efficient Spatial Reuse (II)
• Non-coordinated– Flooding
• With Random Access Delay (RAD) from 0 to TRAD
– Gossiping• With RAD and probability pGSP
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Efficient Spatial Reuse (III)
• Fully coordinated algorithms– Based on global info– NP-problem
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Efficient Spatial Reuse (and IV)
• Partially coordinated algorithms– Based on local info– Counter-Based Broadcasting (CBB)
• Count packets until broadcast timer expires
• If received less than NCBB retransmit
– Distance-Based Broadcasting (DBB)• Based on received power strength
• If closest received is beyond DDBB retransmit
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Quality of Service
• Necessitates– Low delay
• # hops traversed and contention level
– Low jitter• Deviation from periodicity of packet receptions
– High Packet Delivery Ratio (PDR)• Drops and collisions
• Parameters– TDROP = 150ms– Packet Generation period (TPG)– PDR = 95%
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Quality of Service (and II)
• Highly related to energy efficiency
• Centralized Control?– Not practical in Mobile Ad Hoc– High overhead
• Clustering with Cluster Heads (CH)– Schedule the channel access– Some nodes can sleep
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MH-TRACE
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MH-TRACE
• Multi-Hop Time Reservation using Adaptive Control for Energy efficiency
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MH-TRACE (and II)
• Gain access through the contention slots• If gets access fill out the corresponding IS slot• Transmit in the corresponding data slot…• …until it finishes? Starvation?
• Network synchronization through GPS
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NB-TRACE
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Design Principles
• Integrate energy-efficiency in MH-TRACE
• Flooding– IS = (IDnode, IDpacket)
– Go sleep!
• Problems with other algorithms– MH-TRACE is application-based
• NB-TRACE floods the network and prunes
• Maintain a Control Dominating Set (CDS)
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Overview
• Time Division Multiple Access (TDMA)• Initially flood to the whole network• ACK the upstream nodes
• If no ACK in TACK cease rebroadcast
• Algorithm– Initial Flooding (IFL)– Pruning (PRN)– Repair Branch (RPB)– Create Branch (CRB)– Activate Branch (ACB)
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Initial Flooding
• Broadcast packets to one-hop neighbors• Contend channel access and rebroadcast
– Eventually every node has received
• IFL IDD=1 for TIFL so every node wakes up
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Pruning
• 3 states for nodes– Passive– Active– Activate Branch (ACB)
• Problem: stop ACKing from outermost leaf– Eventually, only the source node broadcasts
• Solution: CHs always rebroadcast– Maintain the Non-Connected Dominating Set
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Pruning (and II)
• Eventually 1, 3, 5 and 7 go to passive mode– 0, 2, 4 and 6 make up the broadcast tree
• 5 stops rebroadcast after TACK, 3 stops after 2TACK, 1 stops after 3TACK
• Problem: the nodes are mobile– Re-flood again? Not efficient
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Repair Branch
• Mobility causes CHs to go out and come in– New CH stays in startup mode– Mark the beacon packet– Every node rebroadcasts it
• Problem: broken trees
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Create Branch
• If a node detects an inactive CH in TCRB
– Switch to active and rebroadcast
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Activate Branch
• If a node does not receive for TACB
– Go to ACB mode
– Send ACB packet with pACB
• Into the IS slots in order not to modify MH-TRACE
– If a node receives an ACB packet• Switch to active and begin relying
– If there is nothing to send, they go to ACB mode
– If an ACB node receives data• Switch to active and begin relying
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Packet Drop Threshold
• TDROP used throughout the network
• TDROP-SOURCE used at the source node
• TDROP-SOURCE=TPG
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Simulations
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Overview
• QoS and energy dissipation on– NB-TRACE– MH-TRACE with
• Flooding
– IEEE 802.11 and SMAC with• Flooding• Gossiping• CBB• DBB
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Environment
• Data packets of 110bytes• Node mobility speed from
0.0 to 5.0m/s– 2.5±0.2m/s– 2.2 ±0.4m/s
• 1km wide network• 80 nodes• Data rate of 32Kbps
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Performance Analysis
• 3B = IFL, PRN and RPB• 4B = IFL, PRN, RPB and CPB
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Performance Analysis (II)
• Time– 81.4% in sleep– 16.7% in idle– 2.8% in transmit, receive and carrier sense
• 19.4% of the total energy dissipation
• Energy– 82.4% packet transmissions– 7.5% IS transmissions– 10.1% other control packet transmissions
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Performance Analysis (III)
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Performance Analysis (and IV)
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Varying the Data Rate
• Adjust the superframe size• Adjust # of data slots per frame• Superframe time≈TPG=25ms.
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Varying the Data Rate (and II)
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Varying the Node Density
• 1 by 1km network with 48Kbps
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Conclusions
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Overview
• Most of the work to date targeted at deducing transmit energy dissipation only
• NB-TRACE also targets receiving, idle, sleep and carrier sense dissipation
• According to the 2 (experimental) energy models, transmit energy is not as dominant as thought
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Quality of Service
• Satisfies QoS requirements under several different scenarios– Robustness of the broadcast tree– Maintenance of the NCDS– Cross-layer design– Automatic renewal of channel access
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Energy Dissipation
• It is way lower– Coordinated channel access– Packet discrimination– Lower Average Retransmitting Nodes (ARN)
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Delay
• It is larger with small networks– Restricted channel access
• Maintains a regular delay with bigger networks
• It is much lower with larger networks– High node density– High data rates
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Jitter
• Lower to all but MH-TRACE– Channel access granted by CHs after contend
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Spatial Reuse
• Better than the others– Robustness of channel access– Full integration with MAC layer– IEEE‘s MAC doesn’t prevent excessive
collisions
• No data!
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Energy Model
• Energy savings are related to the model
• Some radios do not support sleep mode or the dissipation difference is small– However, NB-TRACE performs well
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Future Work
• Extend TRACE to multicast and unicast– The blocks are reusable– CHs can become multicasting group members
as they always broadcast
• Realistic environments with channel errors– MH-TRACE is shown to outperform IEEE