MU-MIMO Channel Feedback Using CIR for Beam Scheduling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multi-user multiple-input-multiple-output (MU-MIMO) systems, the lack of full channel matrix information at the network node limits scheduling flexibility, leading to interference and reduced achievable communication rates due to implicit channel feedback based on digital beamforming.
Innovation Solution
User equipment provides explicit channel feedback through channel impulse response (CIR) values for each frequency component, allowing the network node to determine optimal beam allocation and scheduling for MU-MIMO communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If implicit channel feedback based on digital beamforming is used, then the system can operate with limited feedback information, but the network node lacks full channel matrix information which limits scheduling flexibility and causes interference
Solution Approach 1:
The patent implements explicit channel feedback where the UE quantizes and reports channel impulse response (CIR) values for multiple frequency components to the network node. This feedback mechanism provides the network node with full channel matrix information, enabling informed scheduling decisions and precise beam allocation for MU-MIMO communications, thereby resolving the information loss problem while maintaining scheduling flexibility
2Productivity
If the network schedules multiple UEs for MU-MIMO communication with limited channel information, then system resource utilization improves, but multiuser interference increases and achievable communication rates decrease
Solution Approach 1:
The patent applies preliminary action by having the UE perform channel estimation and quantization of CIR values before transmission. The network node receives this pre-processed channel information and uses it to pre-determine optimal beam allocations and scheduling decisions for multiple UEs. This preliminary channel information exchange enables the network to proactively configure MU-MIMO transmissions that avoid interference from the outset, rather than reacting to interference after it occurs
Solution Approach 2:
The patent changes the parameter representation from implicit digital beamforming indices to explicit channel impulse response values across multiple frequency components. This parameter transformation provides the network node with detailed channel state information including amplitude and phase characteristics, enabling precise control of beamforming weights and scheduling decisions to maximize communication rates while eliminating multiuser interference
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication, and to channel feedback for multi-user multiple-input-multiple output (MU-MIMO) communications. For example, the present disclosure provides techniques for explicit channel feedback at an analog beam level for a MU-MIMO system. In some aspects, a user equipment (UE) receives, via an analog receiving beam, reference signals transmitted by a network node via a plurality of analog beams. Based on the received reference signals, the UE determines channel impulse response (CIR) values for each frequency component of one or more frequency components of a frequency range, and transmits CIR information that indicates at least one CIR value to the network node. In another aspect, the network node uses the CIR information to co-schedule multiple UEs for MU-communications, determine one or more beams to be used by the multiple UEs for their MU-MIMO communications, or a combination thereof.