Energy and Spatial Reuse Efficient
Network-Wide Real-Time
Data Broadcasting
in Mobile Ad Hoc Networks
B. Tavli and W. B. Heinzelman
Julián Urbano
[email protected]
Overview
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Introduction
Background
MH-TRACE
NB-TRACE
Simulation
Conclusions
Introduction
Network-Wide Real-Time
Data 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 (NBTRACE)
– Based on MH-TRACE
Background
Energy Dissipation
• Different Categories
– Transmit mode
– Receive mode
– Idle mode
– Carrier sense mode
– Sleep mode
Energy Dissipation (II)
• How to Achieve it?
– Unnecessary carrier sensing
– Idle energy dissipation
– Overhear irrelevant packets
– Transmit energy dissipation
– Reduce overhead
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
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
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
Efficient Spatial Reuse (II)
• Non-coordinated
– Flooding
• With Random Access Delay (RAD) from 0 to TRAD
– Gossiping
• With RAD and probability pGSP
Efficient Spatial Reuse (III)
• Fully coordinated algorithms
– Based on global info
– NP-problem
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
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%
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
MH-TRACE
MH-TRACE
• Multi-Hop Time Reservation using Adaptive
Control for Energy efficiency
MH-TRACE (and II)
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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
NB-TRACE
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)
Overview
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Time Division Multiple Access (TDMA)
Initially flood to the whole network
ACK the upstream nodes
If no ACK in TACK cease rebroadcast
Algorithm
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Initial Flooding (IFL)
Pruning (PRN)
Repair Branch (RPB)
Create Branch (CRB)
Activate Branch (ACB)
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
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
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
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
Create Branch
• If a node detects an
inactive CH in TCRB
– Switch to active and
rebroadcast
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
Packet Drop Threshold
• TDROP used throughout the network
• TDROP-SOURCE used at the source node
• TDROP-SOURCE=TPG
Simulations
Overview
• QoS and energy dissipation on
– NB-TRACE
– MH-TRACE with
• Flooding
– IEEE 802.11 and SMAC with
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Flooding
Gossiping
CBB
DBB
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
Performance Analysis
• 3B = IFL, PRN and RPB
• 4B = IFL, PRN, RPB and CPB
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
Performance Analysis (III)
Performance Analysis (and IV)
Varying the Data Rate
• Adjust the superframe size
• Adjust # of data slots per frame
• Superframe time≈TPG=25ms.
Varying the Data Rate (and II)
Varying the Node Density
• 1 by 1km network with 48Kbps
Conclusions
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
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
Energy Dissipation
• It is way lower
– Coordinated channel access
– Packet discrimination
– Lower Average Retransmitting Nodes (ARN)
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
Jitter
• Lower to all but MH-TRACE
– Channel access granted by CHs after contend
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!
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
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