Control Channel Decoding via Soft-Combining Across Time Slots
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Solution Overview
Problem
In wireless communication networks, particularly in 5G new radio (NR) technology, there is a challenge in achieving low error rates for control channels without excessive resource allocation, which is critical for ultra-reliable and low-latency communications (URLLC) applications, as current methods trade off between control channel resource usage and reliability.
Innovation Solution
The proposed solution involves using soft-combining techniques to decode control messages by receiving and combining coded control symbols across multiple time slots, allowing for high reliability without increasing decoding delay or requiring multi-node coordination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of physical resources are allocated to the control channel to achieve low error rates, then reliability is improved, but resource usage increases and latency increases
Solution Approach 1:
The patent combines control channel transmissions from multiple time slots using soft-combining techniques. The receiver accumulates received signal energy from repeated control channel transmissions across different time slots, allowing successful decoding with fewer total resources allocated while maintaining reliability. This resolves the contradiction by merging temporal resources rather than requiring simultaneous spatial resources.
Solution Approach 2:
The patent uses preliminary decoding attempts on individual time slots before combining. The receiver first attempts to decode control channel messages from single time slots, and only when those fail does it proceed to soft-combining across multiple time slots. This staged approach reduces average latency by succeeding quickly when possible while maintaining the option for higher reliability when needed.
2Reliability
If a large number of physical resources are allocated to the control channel to achieve low error rates, then reliability is improved, but resource allocation increases
Solution Approach 1:
The patent merges control channel transmissions from multiple time slots using soft-combining at the receiver. By accumulating signal energy from repeated transmissions across time, the system achieves high reliability with a smaller total number of physical resources (CCEs) allocated to the control channel, resolving the trade-off between resource usage and reliability.
Solution Approach 2:
The patent employs periodic repetition of control channel transmissions across multiple time slots. Instead of allocating all control channel resources simultaneously, the system transmits control information periodically across time, allowing the receiver to combine these periodic transmissions to achieve the required error rates with reduced total resource allocation.
3Reliability
If control channel transmissions are repeated across multiple time slots, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements soft-combining in a self-service manner where the receiver autonomously performs decoding attempts on individual time slots and automatically proceeds to combine signals from multiple time slots when initial attempts fail. This self-managed approach improves reliability through repeated transmissions while keeping device complexity manageable by using straightforward signal accumulation and retry logic without requiring complex coordination protocols.
Data Source
AI summary
The disclosure provides methods and apparatus which relate to control channel decoding in a wireless communications network. In one aspect, there is provided a method in a wireless device for a wireless communications network. The method includes receiving a first set of coded control symbols on a physical control channel in a first time slot, receiving a second set of coded control symbols on the physical control channel in a second time slot subsequent to the first time slot, and attempting to decode a control message based on the first set of coded control symbols and the second set of coded control symbols using one or more soft-combining techniques.