RNC RACH Utilization Management via Dynamic RLC Parameters
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Solution Overview
Problem
In WCDMA communication networks, the Random Access Channel (RACH) faces limitations such as limited access slots and preamble signatures, leading to collisions and increased latency and Block Error Rate (BLER) as the number of users increases, affecting the quality of the channel and end-user experience.
Innovation Solution
A Radio Network Controller (RNC) dynamically sets Radio Link Control (RLC) parameters to manage RACH utilization by determining the current resource usage level and adjusting parameters like Timer_Poll and Tx_Window_Size to control data transmission on the RACH, preventing overload and maintaining channel quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If more users access the RACH channel simultaneously, then the network capacity and user connectivity are improved, but the channel quality deteriorates due to collisions and limited resources
Solution Approach 1:
The patent applies dynamics by making the RLC parameters dynamic rather than static. The RNC continuously monitors RACH resource utilization and adjusts RLC parameters (such as timer values, window sizes, and data transmission thresholds) in real-time based on current load conditions. This dynamic adaptation allows the system to optimize performance across varying user densities, maintaining channel quality even as user quantity increases.
Solution Approach 2:
The patent implements parameter changes by modifying RLC layer parameters in response to RACH utilization levels. Specific parameters such as T3100 timer, N3100 threshold, and data transmission window sizes are adjusted based on measured RACH conditions. These parameter changes enable the system to control the disposition of UEs to transmit data, effectively managing the trade-off between user capacity and channel quality.
2Productivity
If RACH resource utilization is increased to handle more data traffic, then the productivity of the channel is improved, but the Block Error Rate and latency increase due to overload
Solution Approach 1:
The patent implements feedback mechanisms where the RNC continuously monitors RACH resource utilization, collision rates, and transmission success metrics. Based on this feedback, the system dynamically adjusts RLC parameters to optimize data transmission. When utilization is high, parameters are adjusted to reduce traffic load; when utilization is low, parameters allow for increased throughput, thereby managing the trade-off between productivity and latency.
Solution Approach 2:
The patent applies partial action by controlling the disposition of UEs to transmit data based on current RACH conditions. Rather than allowing all UEs to transmit at maximum rates, the system selectively enables data transmission for UEs in CELL_FACH state based on RLC parameter settings. This partial utilization approach prevents overload while maintaining adequate productivity.
3Reliability
If the number of preamble signatures and access slots is increased to reduce collisions, then the reliability of random access is improved, but the device complexity and network configuration complexity increase
Solution Approach 1:
The patent introduces the RLC layer as an intermediary between the physical RACH access layer and the upper network layers. Instead of modifying physical layer parameters such as preamble signatures and access slots, the RLC layer mediates data transmission by controlling UE disposition to transmit data. This intermediary approach improves random access reliability through parameter adjustment without increasing physical layer complexity or requiring reconfiguration of base station hardware.
Data Source
AI summary
A Radio Network Controller, RNC, and a method performed by the RNC for managing the utilization of a RACH of a WCDMA communication network wherein the RNC is associated with an RBS, wherein the RACH is an uplink channel between UEs and the RBS are provided. The method comprises determining a current resource utilization level of the RACH; setting, based on the determined resource utilization, a value of at least one Radio Link Control, RLC, parameter that controls the disposition of a UE to transmit data on the RACH; and employing the at least one RLC parameter to at least one UE being in a Cell Forward Access Channel, CELL_FACH, state or entering into the CELL_FACH state.