Directional Antenna Network System for Wireless Mesh Interference Reduction
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Solution Overview
Problem
Conventional wireless mesh networks using omni-directional antennas suffer from radio interference and reduced frequency reuse efficiency, leading to lower packet forwarding efficiency and issues like the hidden node problem and carrier sensing failure.
Innovation Solution
A network system with a core node and slave nodes equipped with directional antennas and an antenna control unit that activates specific antennas for receiving and transmitting packets, managing packet forwarding through intermittent periodic transmission and adaptive antenna selection to minimize interference and optimize route formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If omni-directional antennas are used for packet transmission, then coverage area is improved, but radio interference increases and frequency reuse efficiency decreases
Solution Approach 1:
The patent applies local quality by transitioning from uniform omni-directional antenna coverage to localized directional antenna beams. Each slave node activates specific directional antennas to transmit and receive packets only in the direction of the target node, creating localized communication zones. This resolves the contradiction by maintaining coverage through coordinated directional transmissions while eliminating widespread radio interference and enabling frequency reuse in different spatial directions.
Solution Approach 2:
The patent introduces spatial dimensionality by using directional antennas with specific beam directions. Instead of uniform 360-degree coverage in the horizontal plane, the system adds angular orientation as a new dimension for packet transmission. Each slave node selects directional antennas based on the angular position of the target node, transforming the coverage problem from a 2D area problem to a 3D spatial problem that enables frequency reuse through spatial separation.
2Productivity
If directional antennas are used for packet transmission, then frequency reuse efficiency is improved, but device complexity increases due to antenna control requirements
Solution Approach 1:
The patent applies preliminary action by pre-establishing directional link information between slave nodes before actual packet transmission. The antenna control unit stores which directional antenna corresponds to which target node based on pre-acquired link quality and position information. When a packet needs to be transmitted, the system simply retrieves the pre-determined directional antenna setting rather than performing complex real-time antenna selection, thus maintaining high frequency reuse efficiency while reducing control complexity.
Solution Approach 2:
The patent implements self-service through the antenna control unit that autonomously selects and activates the appropriate directional antenna based on stored link information and packet destination. The system does not require complex centralized coordination or real-time negotiations between nodes for antenna selection. Each slave node independently determines the correct directional antenna to use, simplifying the overall system control while maintaining high frequency reuse efficiency through autonomous local decision-making.
3Productivity
If intermittent periodic transmission is used, then packet forwarding efficiency is improved, but transmission time variability increases
Solution Approach 1:
The patent applies periodic action through the intermittent periodic transmission mechanism where the core node transmits packets to slave nodes at regular intervals rather than continuously. Each slave node has designated reception windows during which it actively listens for packets from the core node or other slave nodes. This periodic structure improves forwarding efficiency by creating predictable transmission opportunities and reducing collisions, while the fixed interval pattern actually reduces time variability compared to ad-hoc transmission scheduling.
Data Source
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AI summary
There are proposed: a network system capable of realizing packet forwarding higher in packet forwarding efficiency than in conventional Intermittent Periodic Transmit (IPT) using omni-directional antennas; and the like. Directional antennas are applied to the IPT, and each of slave nodes waits for reception of downlink packets by a directional antenna for receiving the downlink packets in a reception waiting state therefor. Moreover, the downlink packets are treated like polling control signals, and uplink packets are transmitted at a reception time of the downlink packets, whereby a hidden node problem and a carrier sensing problem can be avoided. Furthermore, in accordance with routing protocol in which each of nodes changes directivity randomly by a route formation process, it becomes possible to form a more suitable route.