Distributed Time Slot Allocation in Ad Hoc Wireless Networks
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Solution Overview
Problem
Centralized time slot allocation in ad hoc wireless communication networks is inefficient due to the significant time required for information propagation, especially in mobile multi-hopping networks with frequent topology changes, leading to challenges in meeting quality of service (QoS) requirements and managing time slot interference.
Innovation Solution
A distributed method for allocating time slots using a Local Communication Map (LCM), Time Slot Utilization Map (TSUM), and slot allocation tables, where nodes autonomously manage and reallocate time slots based on routing information and QoS requirements, with mechanisms for detecting and resolving slot interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If centralized time slot allocation is used, then time slot management is simplified and centralized control is achieved, but information propagation time increases significantly and the system cannot adapt quickly to topology changes
Solution Approach 1:
The patent divides the centralized time slot allocation function into distributed segments at each node. Each node maintains its own time slot allocation table and makes independent allocation decisions based on local communication maps, eliminating the need for information propagation to a central controller and back.
Solution Approach 2:
The patent implements dynamic time slot allocation where nodes can autonomously reallocate time slots in response to topology changes. The system transitions from static centralized control to dynamic distributed control, allowing immediate adaptation when nodes move or links change.
2Ease of manufacture
If centralized time slot allocation is used, then time slot allocation is straightforward, but the system cannot meet QoS requirements in mobile multi-hopping networks with frequent topology changes
Solution Approach 1:
Each node autonomously performs time slot allocation and interference detection without requiring centralized coordination. Nodes independently update their allocation tables based on local observations of time slot interference, enabling the system to maintain QoS requirements through self-organizing behavior.
Solution Approach 2:
The patent implements feedback mechanisms where nodes monitor time slot interference and adjust allocations accordingly. When interference is detected on a time slot, nodes receive feedback and reallocate to different time slots, ensuring continuous QoS compliance in dynamic conditions.
3Adaptability or versatility
If distributed time slot allocation is implemented, then adaptability to topology changes improves and information propagation time is reduced, but time slot interference detection and management becomes more complex
Solution Approach 1:
Nodes pre-establish local communication maps that track which time slots are used by neighboring nodes. This preliminary organization of interference information simplifies the detection process, as nodes can quickly consult their pre-built maps rather than analyzing interference from scratch during each allocation decision.
4Speed
If nodes autonomously manage time slots, then response time to topology changes is reduced, but the amount of information each node must process increases
Solution Approach 1:
Each node maintains a local communication map that contains only the information necessary for its specific allocation decisions - namely, which time slots are used by immediate neighbors. This localized information storage reduces the processing burden compared to maintaining global network state, while still enabling autonomous adaptation to local topology changes.
Data Source
AI summary
In a network comprising a source, a destination, and intermediate nodes along a route between the source and the destination, techniques are provided for allocating one or more time slots to transmit a particular data stream along the route based on the QoS requirements to transmit the particular data stream. In one implementation, a Scout Request message (SRM) is sent from the source to the destination to allocate time slots along the route to transmit a particular data stream to the destination. The SRM can include QoS requirements to transmit the particular data stream. Each intermediate node along the route can allocate one or more time slots to transmit the particular data stream based on the QoS requirements needed to transmit the particular data stream along the route.