CCE-Based Implicit Pointing for MU-MIMO Acknowledgement Overhead
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Solution Overview
Problem
In wireless communication systems, particularly in LTE-based MU-MIMO environments, the ambiguity in multiplexing user elements on allocated resources leads to the unnecessary construction and transmission of multiple ACK/NACK banks, wasting bandwidth and increasing overhead.
Innovation Solution
A method for selective use of control channel element (CCE)-based implicit pointing, where acknowledgments are transmitted on multiple acknowledgement banks based on the location of resource blocks and SDMA indices, allowing UEs to determine the appropriate acknowledgement channel, and uplink scheduling grants are transmitted over physical channels composed of CCEs to guide UEs in identifying their acknowledgement channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple ACK/NACK banks are constructed and transmitted to resolve ambiguity in multiplexing UEs on allocated MU-MIMO resources, then reliability of acknowledgement delivery is improved, but downlink overhead and bandwidth waste increase
Solution Approach 1:
The patent segments the acknowledgement delivery mechanism by dividing UEs into different groups based on their resource block allocations. Each group receives acknowledgements through dedicated implicit pointing mechanisms, allowing selective transmission to specific UE groups rather than broadcasting to all UEs. This segmentation reduces the number of ACK/NACK banks needed while ensuring reliable delivery to each group.
Solution Approach 2:
The patent applies local quality by providing different acknowledgement delivery mechanisms to different UE groups based on their specific resource allocations. UEs in the first group receive acknowledgements through one implicit pointing method, while UEs in the second group receive acknowledgements through another method. This localized approach ensures each UE group gets the most appropriate acknowledgement mechanism for its allocation pattern, reducing overall overhead.
2Reliability
If multiple ACK/NACK banks are transmitted to ensure all UEs receive acknowledgements, then completeness of acknowledgement coverage is improved, but downlink overhead increases
Solution Approach 1:
The patent introduces dynamic grouping where UEs are assigned to different groups based on their resource block allocation patterns. The network can dynamically adjust which implicit pointing mechanism to use for each UE group based on current allocation conditions. This dynamic approach allows the system to adapt to different scenarios and reduce overhead while maintaining complete coverage.
Solution Approach 2:
The patent enables UEs to self-determine their acknowledgement reception status by monitoring specific downlink resources based on their uplink allocations. Each UE can autonomously identify which implicit pointing mechanism applies to it and monitor the corresponding resources for acknowledgements. This self-service approach reduces the need for explicit signalling and decreases downlink overhead while ensuring complete coverage.
Data Source
AI summary
A method for selective use of control channel element (CCE)-based implicit pointing. The method includes the step of determining whether a number of multiple user elements (UE) within a multi-user multiple-input multiple-output (MU-MIMO) group is greater than the number of resource blocks allocated to the MU-MIMO group. If the number of UEs in the MU-MIMO group is greater than the number of resource blocks allocated to the MU-MIMO group, the method further includes transmitting to each of the UEs of the MU-MIMO group acknowledgements on acknowledgement channels within a first acknowledgement bank and acknowledgements on acknowledgement channels within a second acknowledgement bank. A first portion of the UEs of the MU-MIMO group receives the acknowledgements on the acknowledgement channels within the first acknowledgement bank and a second portion of the UEs of MU-MIMO group receives the acknowledgements on the acknowledgement channels within the second acknowledgement bank.