CSMA/CA Collision Prevention via Slot Index Allocation
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Solution Overview
Problem
Conventional CSMA/CA schemes fail to effectively manage collisions between homogeneous networks, leading to increased collision rates and reduced resource efficiency, especially when multiple networks coexist in close proximity.
Innovation Solution
The method involves synchronizing neighboring networks, allocating a slot index and contention window size based on the number of networks, and dynamically adjusting the back-off counter value based on channel state and slot index to prevent collisions, using a 2-step synchronization control method and system parameters like beacon shifting sequence indices or network IDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional CSMA/CA scheme is used without considering homogeneous networks, then the scheme is simple to implement, but collision rate increases and resource efficiency decreases
Solution Approach 1:
The invention segments the contention process by introducing slot index-based division. Networks are divided into different groups based on slot indices, where each network only contends during its assigned slot indices. This segmentation prevents collisions between homogeneous networks while maintaining manageable complexity through systematic organization.
Solution Approach 2:
The invention performs preliminary synchronization and slot index allocation before data transmission begins. By pre-synchronizing networks and assigning slot indices in advance, the system establishes a collision-free framework beforehand, allowing networks to operate efficiently without dealing with collisions during actual data transmission.
2Reliability
If back-off counter selection range is increased to maximum CW size to handle collisions, then collision handling capability is improved, but transmission efficiency decreases
Solution Approach 1:
The invention applies local quality by making the back-off counter selection range adaptive rather than uniform. Networks with fewer contending neighbors use smaller CW sizes for faster transmission, while networks experiencing more contention use larger CW sizes. This localized adaptation optimizes both collision handling and transmission efficiency for each specific network context.
Solution Approach 2:
The invention introduces dynamic adjustment of CW size based on the number of networks and contention conditions. The system can adaptively increase or decrease the back-off counter selection range according to real-time network conditions, allowing efficient resource utilization while maintaining reliable collision handling when needed.
3Area of stationary object
If multiple homogeneous networks coexist in narrow area, then network coverage is improved, but collision rate increases significantly
Solution Approach 1:
The invention resolves spatial collision conflicts by introducing a temporal dimension through slot index allocation. Instead of competing in the same time-space domain, networks are distributed across different time slots. This dimensional transformation allows multiple networks to coexist in narrow areas without collisions, as each network transmits during its assigned temporal window.
Solution Approach 2:
The invention implements periodic action through synchronized time slots and periodic back-off counter reductions. Networks operate in periodic cycles where they contend during assigned slots and remain silent during other slots. This periodic structure enables multiple networks to share the same spatial area efficiently by alternating their transmission opportunities in time.
Data Source
AI summary
A method and a target node for preventing collisions between networks communicating based on a carrier sense multiple access/collision avoidance (CSMA/CA) scheme, are provided. The method includes synchronizing an object network with a neighboring network. The method further includes allocating, to the object network, a slot index based on a number of the networks, and a contention window (CW) size. The method further includes setting, for the object network, a back-off counter value based on the CW size. The method further includes reducing the back-off counter value based on a channel state of the object network, and the slot index. The method further includes transmitting data related to the neighboring network based on the back-off counter value.