Convergecast Tree Scheduling for Wireless Sensor Networks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing convergecast scheduling techniques in wireless sensor networks, primarily based on contention-based MAC protocols like CSMA, suffer from data packet collisions and increased latency, which are exacerbated by recovery methods, leading to inefficient data transmission and energy consumption.
Innovation Solution
A method that constructs a convergecast-tree based on hop counts, linearizes it into branches, and schedules packet transmissions using a predetermined criteria to minimize timeslots required for the operation, optimizing the convergecast process by reducing collisions and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If contention-based MAC protocols like CSMA are used for convergecast scheduling, then nodes can transmit data packets freely, but data packet collisions occur frequently causing data losses and increased latency
Solution Approach 1:
The patent applies preliminary action by constructing a convergecast tree and pre-determining transmission schedules for all nodes before the actual data transmission begins. Each node is assigned specific time slots for transmission based on its position in the convergecast tree, eliminating collisions that would occur with free contention-based access. This pre-planned scheduling ensures reliable data delivery while maintaining operational simplicity.
2Reliability
If retransmission methods are used to remedy data losses from collisions, then data delivery reliability improves, but convergecast latency increases and energy consumption increases
Solution Approach 1:
The patent eliminates the need for retransmission by performing preliminary scheduling of all data packets in the convergecast tree. Each node is assigned specific time slots that guarantee collision-free transmission, ensuring data is delivered in the first attempt. This pre-planned approach achieves high reliability without the latency and energy overhead of retransmission protocols.
3Reliability
If radial coordination is implemented to decrease collision probability, then data packet collisions are reduced, but convergecast latency is far from optimal
Solution Approach 1:
The patent applies segmentation by dividing the convergecast network into a tree structure with hierarchical levels, where each node is assigned to a specific level based on its distance from the root. This segmentation allows for optimized scheduling at each level, achieving both collision reduction and minimal latency by processing nodes in a structured bottom-up manner rather than using radial coordination.
Solution Approach 2:
The patent combines preliminary action with segmentation by pre-calculating optimal transmission schedules for each segment of the convergecast tree. This ensures that collisions are avoided while minimizing latency through carefully planned transmission timing at each hierarchical level.
4Productivity
If more timeslots are allocated for packet transmissions, then data delivery rate increases, but the total operation time and energy consumption increase
Solution Approach 1:
The patent achieves high data delivery rates without increasing operation duration by performing preliminary scheduling that optimizes the use of available timeslots. The convergecast tree structure with pre-assigned transmission slots ensures that data flows efficiently through the network without unnecessary delays, maximizing productivity within the minimal required time framework.
Solution Approach 2:
The patent applies continuity of useful action by ensuring that each timeslot in the convergecast schedule is fully utilized for productive data transmission. The hierarchical tree structure and pre-planned schedules eliminate idle timeslots and ensure continuous data flow from all nodes to the root, maximizing data delivery rate without extending the overall operation duration.
Data Source
AI summary
A system that optimizes packet transmissions during a convergecast operation in a convergecast network. During operation, the system receives a request to perform the convergecast operation in the convergecast network. In response to the request, the system constructs a convergecast-tree, which includes the base-station and the plurality of nodes, based on hop counts from the plurality of nodes to the base-station. Next, the system linearizes the convergecast-tree so that the convergecast-tree contains a plurality of linear branches. The system then schedules packet transmission for each of the linear branches and each node in each branch based on a set of predetermined criteria to obtain a scheduled order. Finally, the system performs packet transmissions in the convergecast-tree using the scheduled order. Note that performing the convergecast operation in this way substantially optimizes the convergecast operation by reducing a total number of timeslots required to complete the convergecast operation.