Wireless Multi-Hop Network Transmission Scheduling with Demand-Based Time Slot Allocation
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Solution Overview
Problem
In wireless multi-hop networks, existing transmission scheduling methods fail to efficiently allocate time slots based on varying packet transfer quantities and node connectivity, leading to bottlenecks and reduced packet transfer rates due to assumptions of uniform packet transfer across all nodes.
Innovation Solution
A method and apparatus that calculate transmission demands for each node by considering location and connection information, allocating time slots starting from nodes with the highest demands while avoiding collisions, and adjusting demands to ensure each node receives a guaranteed minimum number of time slots, thereby optimizing time slot allocation and reducing bottlenecks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uniform packet arrival rate is applied to every node, then scheduling table completion is simplified, but packet transfer rate degrades due to bottleneck nodes
Solution Approach 1:
The patent applies local quality by differentiating packet arrival rates across nodes based on their specific characteristics. Each node's packet arrival rate is calculated individually using the formula λ_i = (Σλ_j×h_ji) / (1 - Σh_ij), where λ_j represents the packet arrival rate of neighboring nodes and h_ji represents the probability of packet forwarding. This allows nodes with higher traffic demands to receive more time slots while maintaining manageable scheduling complexity through localized calculations.
2Productivity
If maximum number of nodes are allocated time slots, then channel utilization is maximized, but collision probability increases
Solution Approach 1:
The patent implements dynamics by iteratively adjusting time slot allocations based on calculated transmission demands. The scheduling process dynamically determines the number of time slots N_i for each node using the formula N_i = ceil(λ_i × T / (1 - Σh_ij)), where T is the frame length. This dynamic allocation allows the system to maximize channel utilization while maintaining collision-free transmission by adapting to each node's actual traffic requirements rather than using static uniform allocation.
3Reliability
If TDMA scheme is used for packet collision prevention, then packet transmission reliability is improved, but network throughput is reduced due to idle time slots
Solution Approach 1:
The patent changes parameters by optimizing the frame structure and time slot allocation based on actual transmission demands. The frame length T and number of time slots N_i are adjusted according to calculated packet arrival rates and transmission probabilities. This parameter optimization ensures that time slots are allocated precisely when needed, reducing idle time while maintaining the collision-prevention benefits of TDMA, thereby improving network throughput without sacrificing reliability.
Data Source
AI summary
In a wireless multi-hop network, a transmission scheduling apparatus calculates a transmission demand of every node within the wireless multi-hop network, and allocates a time slot to each node by using the transmission demand of each node.