Random Access Power Level Adjustment for Collision Avoidance
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Solution Overview
Problem
Conventional random access technologies in wireless communication systems face inefficiencies due to high collision probabilities and increased access delays, particularly in scenarios where multiple devices contend for channel resources, leading to wasted resources and unpredictable access times.
Innovation Solution
The implementation of different transmit power levels for wireless communication devices to increase the likelihood of successful message reception in case of collisions, utilizing a strategy where one message is received at a significantly higher power level than others, thereby reducing the risk of subsequent collisions and allowing for a smaller contention window, thus reducing delays and improving spectrum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exponential back-off is used to reduce collision probability, then the reliability of random access is improved, but the access delay increases significantly
Solution Approach 1:
The patent changes the parameter of transmit power level to differentiate between multiple random access attempts. By selecting from multiple power levels (e.g., first power level and second power level where the second is higher than the first), the system can reduce collision probability without relying solely on exponential back-off, thereby reducing access delay while maintaining reliability.
2Productivity
If multiple devices transmit simultaneously to reduce access delay, then productivity is improved, but collision probability increases
Solution Approach 1:
The patent applies local quality by assigning different transmit power levels to different devices or different transmission attempts. This creates differentiation in the transmission characteristics of individual devices, allowing the system to maintain high productivity while reducing collision probability through power-level-based distinction.
3Reliability
If contention window size is increased to reduce collision probability, then reliability is improved, but access delay increases
Solution Approach 1:
The patent introduces transmit power level as an additional parameter beyond contention window size. By utilizing multiple power levels, the system can achieve collision avoidance without proportionally increasing the contention window size, thus maintaining smaller delays while improving reliability.
Data Source
AI summary
A wireless communication device is operated to transmit information on a random access channel of a network node. Operation involves determining a first transmit power level for a transmission of the information, and selecting a first transmission time for the transmission of the information, wherein the selected first transmission time is determined by a number drawn from a first contention window, and wherein the selected first transmission time corresponds to a first amount of time delay that must elapse before transmission of the information occurs. The information is transmitted at the selected first transmission time, at the first transmit power level. When the transmitted information was not successfully received by the network node, a size of a second contention window is determined based on a size of the first contention window and on the first transmit power level. A second transmission time is selected for the transmission of the information, wherein the selected second transmission time is determined by a number drawn from the second contention window and wherein the selected second transmission time corresponds to a second amount of time delay that must elapse before transmission of the information occurs. The information is transmitted at the selected second transmission time, at a second transmit power level.