DCI Design for MU-MIMO Interference Cancellation
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Solution Overview
Problem
In multi-user MIMO transmission systems, user equipment (UE) receiving a downlink resource grant is not aware of interfering signals from other UEs sharing the same resource, leading to inefficient decoding and increased resource consumption due to blind detection processes.
Innovation Solution
Incorporating an MU-MIMO assistance information field in the DCI message to indicate spatial layer assignments and interference information, allowing UEs to perform targeted interference cancellation and improve channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the base station transmits multiple spatial layers to multiple UEs over shared downlink resources in MU-MIMO, then system capacity and resource utilization are improved, but UEs cannot identify interfering signals from other UEs, leading to increased blind detection operations and battery power consumption
Solution Approach 1:
The patent introduces an intermediary mechanism (interference indication information transmitted via DCI messages) that mediates between the base station and UEs to convey interference characteristics. This intermediary information enables UEs to identify and handle interfering signals without performing exhaustive blind detections, thus resolving the contradiction between maintaining high system capacity and reducing UE power consumption.
2Measurement precision
If UEs perform blind detections to identify interfering signals, then decoding accuracy may be improved, but processing time and computational resources are significantly consumed
Solution Approach 1:
The base station performs preliminary action by pre-calculating and indicating interference information (such as interference covariance matrix or interference characteristics) in the DCI message before the UE attempts decoding. This preliminary provision of interference information eliminates the need for time-consuming blind detection processes at the UE, while still achieving accurate decoding through informed interference cancellation.
3Reliability
If the DCI message includes detailed interference information for all other UEs, then UE decoding performance is improved, but DCI message size and control channel overhead increase
Solution Approach 1:
The patent applies local quality by providing interference information selectively and locally rather than globally. The interference indication in the DCI message is tailored specifically to the particular UE and its received spatial layers, containing only the relevant interference characteristics needed for that specific UE's decoding task, thus avoiding unnecessary overhead while maintaining decoding performance.
Data Source
AI summary
Wireless networks support MU-MIMO transmission in which a base station transmits multiple spatial layers or spatial streams over a shared downlink resource to multiple UEs. However, UEs participating in the MU-MIMO transmission may need to manage interference associated with spatial streams intended for other users. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be configured to provide an MU-MIMO transmission to a plurality of user UEs over a same set of resource blocks. The apparatus may be configured to generate a DCI message for each UE. The DCI message may indicate a DL grant to each UE and include an MU-MIMO assistance information field that provides each UE with interference information to better decode the spatial layers.