Contention-Based Uplink Resource Zones for Wireless Latency Reduction
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Solution Overview
Problem
Wireless communication systems, particularly in LTE-based networks, experience significant latency during power-up and network connection due to the dedicated and scheduled allocation of physical resources, which can be frustrating for users and inefficient under low system load conditions.
Innovation Solution
Implementing contention-based uplink access, where UE devices can transmit data on shared contention-based resource zones without waiting for an uplink grant, using identifiers like C-RNTI and dynamically managing modulation and coding schemes to reduce latency and overhead, especially suitable for machine-type communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated and scheduled resources are used for uplink access, then resource allocation reliability is improved, but latency increases significantly during power-up and network connection
Solution Approach 1:
The patent segments uplink resources into two distinct types: dedicated scheduled resources and contention-based resources. This segmentation allows the system to provide guaranteed resource allocation through dedicated channels while simultaneously enabling low-latency access through contention-based channels for scenarios like power-up and network connection, thereby resolving the contradiction between reliability and latency.
Solution Approach 2:
The patent implements dynamic resource selection where the base station can flexibly allocate resources based on real-time conditions. The system dynamically switches between dedicated and contention-based access modes, adjusting the allocation strategy according to network load, device requirements, and channel conditions to optimize both reliability and latency performance.
2Device complexity
If traditional scheduled uplink access is used, then resource allocation control is improved, but system overhead increases under low load conditions
Solution Approach 1:
The patent applies partial action by implementing contention-based access only for specific scenarios where low latency is critical (such as initial connection and power-up), rather than applying scheduled access universally. This selective application reduces the overhead associated with continuous scheduling control while maintaining efficient resource allocation for the most time-sensitive operations.
3Loss of time
If contention-based access is implemented, then latency is reduced for machine-type communication, but collision probability increases
Solution Approach 1:
The patent applies local quality by assigning different access characteristics to different resource types within the uplink spectrum. Contention-based resources are allocated with specific parameters optimized for low-latency machine-type communication, while dedicated resources maintain traditional collision-avoidance mechanisms. This localized optimization allows contention-based access to reduce latency without proportionally increasing overall collision probability.
Data Source
AI summary
A base station employs control signaling for contention-based uplink access from user equipment devices to the base station. Contention-based access configuration is performed via physical downlink control channel signaling. Configuration data sent to the user equipment devices identifies multiple contention-based access zones, along with minimum power headroom values for each contention-based access zone. A probability factor may be used to lower collision possibility by influencing whether the user equipment devices perform contention-based uplink access.