Random Access Channel Preamble Transmission Bypassing Persistence Tests
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Solution Overview
Problem
In packet-based mobile communication networks, the random access channel (RACH) access procedure often results in unnecessary waiting times for user equipment (UE) due to the requirement of persistence tests for every transmission, even under optimal network conditions, leading to potential collisions and delayed data transmission.
Innovation Solution
A modified RACH access method that allows UE to bypass initial persistence tests under certain conditions, such as a predetermined time period since the last transmission or a random condition, enabling immediate preamble transmission if an available access slot is found, thus reducing waiting times and potential collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If persistence tests are required for every UE at beginning of every RACH transmission, then collision resolution is improved, but waiting time increases
Solution Approach 1:
The patent applies dynamics by making the persistence test requirement conditional rather than static. The network entity dynamically adjusts whether persistence tests are required based on current network conditions (traffic load, collision rate). When conditions are favorable, UEs can bypass persistence tests to reduce waiting time; when conditions deteriorate, persistence tests are reinstated to ensure collision resolution.
Solution Approach 2:
The patent changes the parameter of persistence test requirement from a fixed value (always required) to a variable parameter that can be adjusted by the network entity. The network entity modifies this parameter based on measured network conditions, allowing the system to optimize between collision resolution and waiting time reduction by changing the persistence test requirement parameter.
2Reliability
If persistence tests are performed before every RACH transmission, then transmission reliability is improved, but transmission efficiency deteriorates
Solution Approach 1:
The system dynamically adjusts the persistence test requirement based on real-time network conditions. When traffic load is low and collision rates are minimal, the network entity allows UEs to bypass persistence tests, thereby improving transmission efficiency. When network conditions worsen, persistence tests are reinstated to maintain transmission reliability.
Solution Approach 2:
The network entity changes the operational parameter of persistence test requirement from mandatory to optional based on network conditions. This parameter change allows the system to optimize transmission efficiency by eliminating unnecessary persistence tests when network conditions are favorable, while maintaining reliability when conditions require it.
3Loss of energy
If UEs wait for persistence test results before transmitting, then channel load is reduced, but access delay increases
Solution Approach 1:
The network entity performs preliminary assessment of network conditions and proactively informs UEs whether persistence tests are required. This preliminary action allows UEs to prepare appropriately - either skipping persistence tests immediately when not required, or performing them when required - thereby optimizing the balance between channel load reduction and access delay.
Solution Approach 2:
The system implements feedback mechanisms where the network entity continuously monitors network conditions (traffic load, collision rate) and provides feedback to UEs about whether persistence tests are required. This feedback loop enables UEs to adjust their transmission behavior accordingly, reducing channel load when appropriate while minimizing access delay through informed decision-making.
Data Source
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AI summary
A method is provided for transmitting a message comprising one or more preambles and a message body from a user equipment device to a network entity. The method includes determining whether it is allowed to transmit a first preamble of the message to the network entity in an immediately available time slot of a random access channel, transmitting the first preamble if it is allowed, and transmitting the message body if a positive acknowledgement to the preamble is received from the network entity on another channel. The user equipment device may determine transmitting the preamble invariably, based on a persistence value or an indication received from the network entity, based on whether the device has not transmitted on the random access channel for longer than a predetermined, or based on whether the device has not transmitted on the random access channel for longer than a random time period.