Scheduling Request Control for Cellular Uplink Interference
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Solution Overview
Problem
In cellular communication systems, particularly in E-UTRA, the frequent transmission of scheduling requests (SRs) due to 'bursty' data applications like VoIP leads to high levels of unnecessary SRs, causing interference and increasing uplink scheduler response time, which affects voice quality and resource usage.
Innovation Solution
Implementing restrictions on the triggering and transmission of SRs, such as suppressing SRs if one was sent recently or during periods of high traffic, by setting thresholds for Time Transmission Intervals (TTIs) or uplink grants, and dynamically varying these parameters based on resource availability and traffic patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If scheduling requests are transmitted frequently to request uplink resources, then resource allocation responsiveness is improved, but uplink interference increases and resource usage efficiency deteriorates
Solution Approach 1:
The patent implements periodic scheduling request transmission with configurable intervals. Instead of continuous transmission, SRs are sent at periodic intervals determined by the network, allowing the system to maintain responsiveness while reducing overall transmission frequency and interference. The periodic nature enables the network to control the timing and density of SR transmissions.
Solution Approach 2:
The patent introduces dynamic adjustment of SR transmission parameters based on network conditions and traffic patterns. The network can dynamically configure SR periodicity, adjust transmission timing, and modify behavior based on observed traffic characteristics. This dynamic control allows optimization of responsiveness while adapting to varying interference conditions.
2Reliability
If scheduling requests are transmitted continuously during bursty data traffic, then uplink resource availability is improved, but transmission overhead increases and resource usage efficiency deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where the network monitors SR transmission patterns and traffic characteristics, then adjusts SR configuration accordingly. The network receives feedback about actual traffic patterns and resource allocation outcomes, using this information to optimize SR periodicity and timing. This closed-loop control reduces unnecessary SR transmissions while maintaining adequate resource availability.
Solution Approach 2:
The patent changes SR transmission parameters dynamically based on observed traffic patterns. Instead of fixed continuous transmission, the system adjusts SR periodicity, timing offsets, and transmission behavior based on traffic characteristics. This parameter adaptation reduces overhead during low-activity periods while maintaining reliability during bursty traffic.
3Quantity of substance
If scheduling request periodicity is increased to reduce overhead, then transmission overhead is reduced, but scheduling response time increases
Solution Approach 1:
The patent implements preliminary configuration of SR resources and periodicity by the network based on predicted traffic patterns. The network pre-configures optimal SR parameters before traffic bursts occur, preparing the system in advance to handle upcoming traffic demands efficiently. This preliminary action allows longer periodicity while maintaining quick response to actual traffic needs.
Solution Approach 2:
The patent uses dynamic adjustment of SR periodicity where the network can change the periodicity value based on observed traffic patterns and performance requirements. During periods requiring faster response, the network decreases periodicity; during stable low-traffic periods, it increases periodicity to reduce overhead. This dynamic behavior optimizes the trade-off between overhead and response time.
Data Source
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AI summary
A method of scheduling resources in a communications link wherein a scheduling requests are transmitted from a first entity to a second entity comprising determining if any of the following conditions exist: the time elapsed since the last scheduling request exceeds a designated time; the up-link requirement exceeds a predetermined level; or semi-persistent scheduling exists; and if so, suppressing the transmission and/or triggering of scheduling requests.