Core Node Time Division for Wireless Multihop Collision Avoidance
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Solution Overview
Problem
Current network systems using CSMA/CA protocol for core nodes in wireless multihop networks face inefficiencies due to random backoff times, leading to low communication efficiency and increased costs with multiple wireless modules, and suffer from bi-directional collisions and interference when uplink and downlink traffic are mixed.
Innovation Solution
A network system with a core node and slave nodes that utilize indication frames to differentiate between uplink and downlink data frames, allowing for dynamic time allocation and separate transmission and reception control, thereby reducing random backoff effects and enabling efficient intermittent periodic transmission (IPT) even with a single wireless module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CSMA/CA protocol with random backoff is used for core node transmission, then collision avoidance is achieved, but communication efficiency deteriorates due to random standby time
Solution Approach 1:
The patent applies dynamics by making the standby time adjustable rather than fixed or purely random. The core node dynamically sets different standby time periods based on the destination node, allowing optimization of communication efficiency while maintaining collision avoidance. This is achieved through the standby time period setting unit that configures specific standby durations for different destination nodes.
Solution Approach 2:
The patent changes the parameter of standby time from a random value to a controlled, destination-specific value. By modifying the standby time parameter based on destination node identification, the system achieves both collision avoidance and improved communication efficiency through intermittent periodic transmission.
2Object-affected harmful factors
If multiple wireless modules are used for separate uplink and downlink transmission, then radio wave interference is reduced, but device cost and complexity increase
Solution Approach 1:
The patent segments the transmission time into distinct uplink and downlink periods through time division. By controlling the direction of data transmission in different time slots, the system eliminates radio wave interference between uplink and downlink without requiring separate wireless modules, thus reducing device complexity while maintaining interference reduction.
Solution Approach 2:
The patent implements periodic action by alternating between uplink and downlink transmission periods. The core node periodically switches transmission directions, creating a time-division multiplexed system that prevents simultaneous bidirectional transmission and eliminates interference without additional hardware.
3Device complexity
If uplink and downlink traffic are mixed in a single channel, then device complexity is reduced, but bi-directional collision occurs
Solution Approach 1:
The patent applies periodic action by establishing distinct uplink periods and downlink periods in the transmission timeline. During uplink periods, slave nodes transmit to the core node; during downlink periods, the core node transmits to slave nodes. This periodic separation prevents bi-directional collisions while using a single wireless module.
Solution Approach 2:
The system dynamically controls transmission direction based on the current period type (uplink or downlink). The core node and slave nodes adapt their transmission behavior according to the prevailing period, enabling efficient single-channel operation without bi-directional collisions.
Data Source
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Figure 3A~3D
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AI summary
The present invention proposes a network system, etc., that are suitable for improving the communication efficiency of an entire network even when a CSMA, etc., are adopted. A network system for transmitting uplink/downlink traffics using a route having a tree structure with a root node, a plurality of inner nodes, and a plurality of leaf nodes, wherein the root node transmits a downlink frame to the inner nodes and leaf nodes at intervals equal to or greater than an additional wait time differing for each destination node. The root node transmits a downlink frame at, for example, an interval consisting of the additional wait time plus a quality assurance time for assuring communication quality. An interval which is a varying time interval but equal to the additional wait time at the least is assured, whereby the communication efficiency of an entire network is improved.