HARQ Process Collision Avoidance in LTE TDD Uplink
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE wireless communication systems, particularly in TDD mode, collisions between uplink packet re-transmissions and new transmissions within the same HARQ process occur due to synchronous HARQ and semi-persistent scheduling, leading to resource inefficiency and packet delays, especially for VoIP services.
Innovation Solution
A method is implemented to detect such collisions and dynamically allocate resources for new uplink packet transmissions to a different HARQ process, avoiding collisions with re-transmissions, thereby optimizing resource utilization and reducing packet delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If synchronous HARQ and semi-persistent scheduling are used in LTE TDD mode, then resource allocation is simplified and VoIP services are supported, but collisions between uplink packet re-transmissions and new transmissions occur within the same HARQ process
Solution Approach 1:
The patent introduces dynamic load balancing mechanisms that adaptively adjust HARQ process assignments based on real-time collision detection. The system monitors HARQ process states and dynamically reallocates uplink resources to prevent collisions between re-transmissions and new transmissions, while maintaining the overall synchronous HARQ framework.
Solution Approach 2:
The patent modifies HARQ process parameters including process IDs, timing offsets, and resource allocations to avoid collisions. By changing these parameters dynamically based on detected collision conditions, the system resolves conflicts while preserving the semi-persistent scheduling structure for VoIP services.
2Loss of time
If the number of HARQ processes is minimized to reduce delays, then packet delay is reduced, but resource utilization efficiency decreases due to collisions
Solution Approach 1:
The patent implements feedback mechanisms where the system detects collisions between re-transmissions and new transmissions in real-time. Based on this feedback, the system dynamically adjusts HARQ process assignments and resource allocations to optimize both delay performance and resource utilization efficiency, achieving a balance between the two conflicting objectives.
Solution Approach 2:
The patent introduces dynamic load balancing that adapts the allocation of uplink resources across HARQ processes based on actual traffic conditions and collision patterns. This dynamic adjustment allows the system to maintain low delay while improving resource utilization by preventing collisions through intelligent resource distribution.
3Reliability
If re-transmissions are prioritized over new transmissions in semi-persistent scheduling, then reliability of re-transmitted packets is improved, but new packet transmissions experience delays and resource conflicts
Solution Approach 1:
The patent applies different scheduling priorities to different HARQ processes based on their current state and traffic type. Instead of a uniform priority scheme, the system assigns local quality differences by dynamically adjusting which HARQ processes handle re-transmissions versus new transmissions, thereby resolving conflicts and reducing delays for new packets while maintaining re-transmission reliability.
Data Source
AI summary
In accordance with exemplary embodiments of the invention there is a method and apparatus to detect with a hybrid automatic repeat request function a collision between an uplink packet re-transmission and a new uplink packet transmission within a hybrid automatic repeat request process, and in response, to dynamically allocating resources for transmitting the new uplink packet transmission in a different hybrid automatic repeat request process that does not collide with the uplink packet re-transmission. In accordance with other exemplary embodiments of the invention, there is a method and apparatus to transmit a packet re-transmission in a hybrid automatic repeat request process using a semi-persistently scheduled uplink resource, and responsive to receiving a dynamic allocation of a different hybrid automatic repeat request process, to transmit a new packet using the dynamically allocated different hybrid automatic repeat request process.