Ad-hoc Network Collision Avoidance via Concealed Node Detection
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Solution Overview
Problem
In mobile ad-hoc networks, collisions between concealed nodes reduce network performance due to the lack of coordination in channel access, especially when multiple nodes share an intermediate node, leading to network blockages and inefficient use of transmission resources.
Innovation Solution
A method that determines the probability of collision-free data transmission by identifying concealed nodes and evaluating their transmission volumes, allowing for reduced coordination processes, such as RTS-CTS, only when necessary, thereby optimizing channel allocation and minimizing co-ordination processes between nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RTS-CTS method is used to avoid collisions between concealed nodes, then collision avoidance is improved, but transmission capacity is reduced because RTS and CTS messages consume transmission resources
Solution Approach 1:
The patent applies preliminary action by having nodes proactively identify concealed nodes and predict potential collisions before actual data transmission occurs. The system uses control messages to scout for concealed nodes and determine collision probabilities in advance, allowing the node to decide whether to use RTS-CTS or direct transmission based on the predicted risk, thereby avoiding unnecessary reservation messages.
Solution Approach 2:
The patent changes the parameter of transmission mode selection based on the identified collision probability. When the probability of collision-free transmission is high, the system switches to direct transmission mode to maximize capacity. When collision probability is high, it switches to RTS-CTS mode to ensure reliability. This dynamic parameter adjustment optimizes the trade-off between reliability and productivity.
2Reliability
If RTS-CTS method is used for all transmissions, then collision avoidance is improved, but efficiency of transmission channel is reduced due to excessive coordination overhead
Solution Approach 1:
The patent applies partial action by selectively applying RTS-CTS only when necessary (when concealed nodes are identified and collision probability is high), rather than applying it universally to all transmissions. This partial application reduces coordination overhead and improves channel efficiency while maintaining collision avoidance where needed.
Solution Approach 2:
The system implements self-service by having each node autonomously identify concealed nodes and determine the appropriate transmission mode based on local conditions. Each node independently evaluates the transmission environment and makes decisions without requiring centralized coordination, reducing overall system overhead while maintaining efficiency.
3Reliability
If concealed nodes are identified and coordinated, then network performance is improved, but complexity of coordination processes increases
Solution Approach 1:
The patent segments the coordination process into distinct phases: concealed node identification phase (using control messages), collision probability evaluation phase, and transmission mode selection phase. This segmentation simplifies the overall complexity by breaking down the coordination task into manageable, sequential steps that each node can execute independently.
Solution Approach 2:
The patent uses control messages as intermediaries to facilitate concealed node identification. These control messages act as mediators that carry information about concealed nodes between adjacent nodes, enabling the system to identify and coordinate without requiring direct complex interactions between all nodes, thereby simplifying the coordination process.
Data Source
AI summary
A method for multi-hop data transmission in an ad-hoc network comprising concealed nodes. A source node determines the probability of a collision-free transmission of data to the following nodes and if a high probability of collision-free transmission is present, transmits a data packet to a following node without coordinating transmission-channel allocation with concealed nodes disposed in the vicinity of the next node.