XD: A Cross-Layer Designed Data Collection Mechanism for Mission-Critical WSNs in Urban Buildings
Summary (2 min read)
Introduction
- Such redundancy is desired by mission-critical applications in that the data delivery rate tends to be high and the end-to-end delay tends to be low.
- The conventional TDMA mechanisms do not scale to the density of the WSNs.
- In their design, nodes of the same magnetic charge send data at the same time slot.
- The authors describe the of XD in detail and provide the rationale o layer designed mechanism achieves relia sensor data collection.
A. Path Discovery
- Consider th magnet and the data as metallic nails.
- T attracted towards the sink according to the m as the nails are attracted towards the magn in MD llision avoidance mechanism is llected from an the simulations, tacks, MD with delivery rate and use of the multif-the-art TDMA commonly-used indicate that XD Zigbee stack.
- Ll to the state-ofing the TDMA nces support that ction mechanism nd yet effective.
- The mag in the interest broadcast phase su disseminated towards the sink in the At the interest broadcast phase, th charge is set the highest charge an packet to its neighbors.
- The node then records this mag the interest message to its neigh magnetic charges from the sink to s data in the reverse direction, from h points in the magnetic field.
B. Data Forwarding
- XD incorporates a hybrid mechanism that utilizes informati Even if there is no contention in delivery rate may still suffer from commonly seen in wireless network proper magnetic charges etic influence of the data determined by the hop propagated based on the high-charge nodes.
- In Figure 2, node A and B are sending nodes and the packets collide at node C. The number on the node indicates the assigned magnetic charge.
- A significant amount of the collisions can be further reduced by separating the sending time of the nodes at different levels, hinting the benefit of a TDMA strategy to the design.
- Packets travelling multiple disjoint paths may collide at the sink node.
- The data delivery rate at the low traffic load case is effectively raised to 100% while the end-to-end delay is slightly compromised.
B. MD with ZMAC:
- ZMAC is a hybrid CSMA and TDMA mechanism.
- The schedule used by its TDMA component is derived by the DRAND [9] algorithm which requires topological information in the two-hop neighborhood.
- In ZMAC, although every node has its slots for transmission, it allows nodes competing sending data at the slots which are not assigned.
- From mid-load cases and on, the end-to-end delay is raised to the scale of seconds and the data delivery rate begins to drop afterwards.
- Combined with the multiple shortest paths discovered by MD, XD performs, in terms of data delivery rate and end-toend delay, better than the Zigbee stack and just as well to the state of the art.
Did you find this useful? Give us your feedback
Citations
49 citations
Cites background from "XD: A Cross-Layer Designed Data Col..."
...For many of those operations, there is usually also a delay bound associated with them and require the messages sent out by the sink node to be received at destined receivers within a designated time bound [14]–[16]....
[...]
7 citations
Cites background from "XD: A Cross-Layer Designed Data Col..."
...We investigate a fundamental scheduling problem of both theoretical and practical importance, called multitask schedulability problem, i.e., given multiple data forwarding tasks, to determine the maximum number of tasks that can be scheduled within their deadlines and work out such a schedule....
[...]
2 citations
1 citations
References
5,147 citations
"XD: A Cross-Layer Designed Data Col..." refers background in this paper
...About half of the packets are collided which results in a significant data delivery rate for mid-load and high-load cases....
[...]
3,848 citations
1,944 citations
784 citations
762 citations
"XD: A Cross-Layer Designed Data Col..." refers background or methods in this paper
...One is C component of ve IEEE 802.15.4 onent is adopted ther suite consists C [ 8 ]....
[...]
...Using traces co WSN deployed in an urban building to drive we compare XD to two other protocol s ZMAC [ 8 ] and Zigbee [5] in terms of data end-to-end delay....
[...]