RLC Timer Adaptation via HARQ Feedback for Radio Resource Efficiency
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Solution Overview
Problem
The existing communication network protocols, particularly in the E-DCH protocol stack, face challenges in accurately setting RLC timers due to the varying delays caused by Hybrid Automatic Repeat Request (HARQ) retransmissions, leading to inefficient radio resource utilization and potential window stalling and unnecessary retransmissions.
Innovation Solution
The solution involves using HARQ feedback to accurately set and restart upper-layer timers, such as RLC timers, based on the successful or unsuccessful receipt status of packet data, thereby optimizing the operation of the upper-layer protocols and reducing unneeded waiting times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ retransmissions are used to ensure reliable data transmission, then transmission reliability is improved, but transmission delay varies substantially making timer setting difficult
Solution Approach 1:
The patent implements feedback mechanisms where the upper layer receives status information from the lower HARQ layer about transmission success or failure. This feedback enables the upper layer to adaptively adjust timer settings based on actual transmission outcomes, resolving the contradiction between maintaining reliability through retransmissions and setting accurate timers despite variable delays.
Solution Approach 2:
The patent makes timer settings dynamic rather than static. Timer values are adjusted based on real-time HARQ transmission status, allowing the system to adapt to varying delay conditions while maintaining reliable transmission. This dynamic adjustment resolves the conflict between reliability assurance and timer accuracy.
2Reliability
If conservative timer values are used to account for HARQ delay variations, then transmission reliability is improved, but radio resource utilization deteriorates due to unneeded waiting times
Solution Approach 1:
Instead of using excessively conservative timer values that guarantee reliability but waste resources, the patent applies partial action by setting timers based on actual transmission status. This allows the system to achieve sufficient reliability without the excessive waiting times that would result from overly conservative timer settings, thereby improving radio resource utilization.
Solution Approach 2:
The patent changes timer parameters dynamically based on HARQ status rather than using fixed conservative values. This parameter adaptation allows the system to maintain reliability while avoiding unnecessary waiting times, thus improving overall productivity and radio resource utilization.
3Productivity
If short timer values are used to improve radio resource utilization, then productivity is improved, but transmission reliability deteriorates due to window stalling and unnecessary retransmissions
Solution Approach 1:
The patent uses feedback from HARQ transmission status to set appropriate timer values. This feedback mechanism ensures that timers are neither too short (causing window stalling) nor too long (wasting resources), but optimally matched to actual transmission conditions, thereby maintaining both reliability and productivity.
Solution Approach 2:
The patent implements dynamic timer adjustment based on real-time transmission status. This dynamic approach allows the system to use shorter timers when transmission is successful (improving productivity) while extending timers when retransmissions are needed (maintaining reliability), thus resolving the contradiction between the two objectives.
4Device complexity
If RLC timers are set based on estimated RTT without HARQ status information, then device complexity is reduced, but measurement precision deteriorates leading to inefficient resource utilization
Solution Approach 1:
The patent introduces an intermediary feedback mechanism that provides HARQ status information to the upper RLC layer. This intermediary information enables precise timer setting without significantly increasing overall system complexity, as the feedback utilizes existing protocol interfaces and status indicators already present in the HARQ mechanism.
Data Source
AI summary
The present invention relates to a method and an arrangement for obtaining efficient radio resource utilization over a radio interface in a communication network comprising a transmitting entity (18) transmitting data over said radio interface to a receiving entity (15), said transmitting entity (18) comprising at least an upper layer utilizing an automatic repeat request (ARQ) protocol on top of a lower layer utilizing a hybrid automatic repeat request (HARQ) protocol, whereby a timer in said upper layer is arranged to supervise operation of said upper layer. Said timer is set based on an indication of receipt status of the transmitted data in said receiving entity (15) according to said lower layer hybrid automatic repeat request protocol.