Wireless Packet Access Using Erasure Coding for Collision Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multiple access protocols in wireless networks, such as CSMA/CA, suffer from collisions and sub-optimal data rates due to the lack of effective coordination between users, leading to inefficiencies in channel usage and increased packet loss.
Innovation Solution
Implementing an erasure correcting code within the CSMA/CA protocol, where the access point determines the appropriate code parameters and contention window width based on the number of users, allowing for optimized data transmission and collision recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If users transmit packets at random times without coordination, then device complexity is reduced, but packet loss increases due to collisions
Solution Approach 1:
The patent introduces an intermediary coordination mechanism where users listen to the channel before transmission and follow protocol rules (contending for the channel, respecting backoff periods) to coordinate access without a central controller. This intermediary protocol layer reduces collisions while maintaining distributed operation.
Solution Approach 2:
The patent implements feedback mechanisms where users monitor channel activity, detect collisions through acknowledgments, and adjust their transmission behavior accordingly (increasing backoff periods after collisions). This feedback loop enables dynamic adaptation to channel conditions and reduces packet loss.
2Reliability
If users listen to the channel before transmitting (CSMA/CA), then packet loss due to collisions is reduced, but productivity decreases due to waiting time
Solution Approach 1:
The patent makes the contention window dynamic, adjusting its size based on observed collision rates and channel conditions. When collisions are frequent, the window expands to reduce contention; when the channel is clear, the window contracts to improve utilization. This dynamic adaptation balances reliability and productivity.
Solution Approach 2:
The patent changes key protocol parameters (contention window size, backoff period, transmission power) based on channel conditions and traffic load. By dynamically adjusting these parameters, the system optimizes the trade-off between collision avoidance and channel utilization, improving overall data rate.
3Productivity
If the contention window is reduced to increase transmission opportunities, then productivity increases, but collision probability increases
Solution Approach 1:
The contention window is implemented as a dynamic parameter that automatically adjusts based on channel conditions. The system contracts the window when the channel is clear to maximize transmissions, and expands it when collisions are detected to reduce contention probability, thus balancing productivity and reliability.
Solution Approach 2:
The protocol enables self-adjustment through distributed feedback mechanisms where each user independently modifies its contention parameters based on local observations of channel activity and collision experience, without requiring centralized control.
4Reliability
If erasure correcting coding is applied to recover collided packets, then packet loss is reduced, but device complexity increases
Solution Approach 1:
The patent employs lightweight erasure correcting codes (such as Reed-Solomon or simple parity codes) that provide adequate packet recovery capability with minimal computational overhead. These codes are designed to be computationally efficient and easy to implement, providing reliability without excessive complexity.
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
The present invention relates to a system for transmitting data packets, comprising at least one access point and at least one terminal. Said access point comprises means for receiving data packets transmitted by said terminal in accordance with a multiple access protocol with carrier detection, as well as means for transmitting to said terminal at least the width of the contention window that said terminal must observe when transmitting a packet. According to the invention, said transmitted packets are encoded by means of one deletion corrector code, and said access point comprises means for decoding the packets received. The invention can be used in local wireless networks.