1 Introduction
2 Related work
3 Proposed ANT
3.1 ANT overview
3.2 Delivery probability
3.3 Cooperative willingness
3.3.1 Reciprocity factor
3.3.2 Resource factor
3.4 Buffer management
3.4.1 Packet quality
3.4.2 Buffer allocation
3.5 Forwarding decision
3.5.1 Forwarding pattern switch
3.5.2 Forwarding algorithm
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First, for each packet in L, node i determines its type and quality on node j.
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Second, node i sorts L based on the packets’ types and qualities on node j, that is, prime packets are in front of ordinary packets, and packets with high qualities are in front of those with low qualities for each type. This is to ensure packets are forwarded in a decreasing order of their worthiness.
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Third, node i sends packets in L from head to tail to node j. For each packet m in L, if node i receives a feedback of ACK, which indicates packet m has been received by node j, node i checks whether the number of duplication hops exceeds the duplication threshold. If h m < DT, it is in the replication pattern. In this case, node i updates h m and updates \( {d}_m^{\max } \) to D m (j) if \( {d}_m^{\max}\le {D}_m(j) \). If h m = DT, it is in the entrusting pattern and node i deletes packet m after it has been received by node j. If node i receives a feedback of REJ, which indicates packet m is rejected by node j due to buffer overflow, node i stops forwarding the rest of the packets in L.
4 Simulations
4.1 Simulation setup
Experimental data set | Reality | Inf06 |
---|---|---|
Device | Phone | iMote |
Network type | Bluetooth | Bluetooth |
Duration (days) | 246 | 3 |
Granularity (seconds) | 300 | 120 |
Number of contacts | 110,000 | 191,000 |
Parameter | Value |
---|---|
Number of nodes | 97 (Reality), 78 (Inf06) |
Packet size (KB) | 50 |
Deadline | 10 days (Reality), 48 h (Inf06) |
Buffer size (MB) | 12 |
Bandwidth (Mbps) | 2 |
T (hour), α, H
| 1, 0.8, 10 |
σ
1, σ
2, σ
3, σ
4
| 0.25 |
w
1 (for buffer), w
2 (for power) | 0.5, 0.5 |
Battery capacity | 1500 mAh |
Threshold for the resource | 40–80 % |
DT | 3 |
Number of collection points | 2 |