Variable Packet Copy Transmission for CRDSA Throughput
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Solution Overview
Problem
Existing methods for data transmission over a shared channel among multiple users, such as Slotted ALOHA and CRDSA, face limitations in throughput, especially at high traffic loads, with CRDSA peaking at approximately 55% successful transmission attempts, far from the maximum possible value of 100%.
Innovation Solution
The method involves varying the number of copies of data packets transmitted by users within a frame, using a probability distribution to determine the number of copies, allowing for a peak throughput of 78% and maintaining high success rates up to 80% system load by switching between Slotted ALOHA and CRDSA based on traffic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of copies of data packets is increased to improve transmission reliability, then the throughput increases, but the system complexity and resource consumption increase
Solution Approach 1:
The patent applies dynamics by making the number of packet copies variable rather than fixed. Each user dynamically adjusts the number of copies (K) based on channel conditions, traffic load, and priority levels. This dynamic adaptation allows the system to optimize between reliability and complexity in real-time, transmitting more copies only when necessary for high-priority or error-prone transmissions.
Solution Approach 2:
The patent changes the parameter of copy number from a fixed value to a variable parameter that can be adjusted according to different conditions. The system modifies the number of copies based on traffic load, channel quality, and priority requirements, enabling flexible control over the trade-off between transmission reliability and system resource consumption.
2Productivity
If the number of copies of data packets is increased to improve throughput, then the data transmission efficiency increases, but the channel resource consumption increases
Solution Approach 1:
The patent utilizes parameter changes by adjusting the copy number (K) as a variable parameter that responds to channel conditions and traffic patterns. This allows the system to optimize throughput by increasing copies when channel conditions are poor or traffic is light, while reducing copies when channel conditions are good or traffic is heavy, thereby efficiently managing channel resource consumption.
Solution Approach 2:
The system dynamically adjusts the number of packet copies based on real-time channel conditions and traffic load. This dynamic behavior enables the system to achieve high throughput when necessary while conserving channel resources during periods of good channel conditions or high traffic loads, resolving the contradiction between productivity and resource consumption.
3Device complexity
If the Slotted ALOHA method is used to manage uncoordinated multiple access, then the system simplicity is maintained, but the peak throughput is limited to approximately 36.8%
Solution Approach 1:
The patent applies segmentation by dividing the transmission frame into multiple slots and allowing users to transmit multiple packet copies in different slots. This segmentation of the transmission medium enables the system to achieve higher throughput by distributing packets across multiple time slots, reducing collisions while maintaining the simplicity of the Slotted ALOHA access mechanism.
Solution Approach 2:
The patent utilizes copying by transmitting multiple copies of each data packet across different time slots. This copying mechanism increases the probability of successful transmission and improves peak throughput beyond the 36.8% limit of traditional Slotted ALOHA, while the copies can be managed through simple interference cancellation techniques that preserve system simplicity.
4Reliability
If the CRDSA method with fixed two copies per packet is used, then the interference cancellation capability is improved, but the throughput peaks at approximately 55% and cannot reach 100%
Solution Approach 1:
The patent overcomes the 55% throughput ceiling of fixed two-copy CRDSA by making the number of copies dynamic. Users can transmit more than two copies when channel conditions warrant it, and the interference cancellation process is extended to handle variable numbers of copies. This dynamic approach allows the system to achieve throughput close to 100% under light load conditions while maintaining robust interference cancellation capability.
Solution Approach 2:
The patent creates a composite access scheme that combines elements of Slotted ALOHA with enhanced CRDSA capabilities. The system uses a composite approach where multiple copies with variable repetition factors are transmitted, and interference cancellation is applied iteratively. This composite method integrates the simplicity of ALOHA with the advanced interference resolution of CRDSA, achieving throughput near the theoretical maximum of 100%.
Data Source
AI summary
The invention is related to a method of transmitting data whereby a transmission channel towards an access point (10) is shared among a plurality of users (12), the data being transmitted using the Contention Resolution Diversity Slotted ALOHA (CRDSA) method. According to the invention the number of copies (14a,14b, 14c; 16a, 16b, 16c; 18a,18b,18c) of data packet (14, 16, 18) transmitted simultaneously by a user (12) within one frame is varied.