Multi-user beam alignment with probing beams and feedback
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Solution Overview
Problem
Current beam alignment schemes in millimeter-wave communications are inadequate for handling multiple active users effectively, particularly in scenarios with high path-loss and shadowing, as they assume a single active user and do not account for multi-path conditions.
Innovation Solution
A method and system for multi-user beam alignment that uses a set of probing beams to determine a data transmission beam based on feedback, employing a Tulip Design for scanning beams to minimize the uncertainty region of angle of departure, and a greedy algorithm to optimize beam alignment policies, allowing for efficient beam alignment in non-interactive modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If narrow beams are used to increase beamforming gain, then communication reliability improves, but beam alignment complexity increases
Solution Approach 1:
The beam alignment process is segmented into two distinct phases: a probing phase where wide scanning beams are used to identify candidate directions, and a refinement phase where narrow data transmission beams are precisely aligned based on feedback from the probing phase. This segmentation allows the system to first粗 locate beam directions using simple wide beams, then refine alignment using narrow beams only in identified candidate directions, reducing overall complexity while maintaining high beamforming gain
Solution Approach 2:
The probing phase acts as a preliminary action that identifies candidate beam directions before the actual data transmission. By performing this preliminary scanning and identification using wide beams, the system prepares the necessary information (candidate directions and feedback) that enables subsequent precise alignment with narrow beams, avoiding the need to test all possible directions with narrow beams
2Productivity
If beam alignment is performed for multiple users, then system capacity improves, but alignment time increases
Solution Approach 1:
The system merges the beam alignment processes of multiple users by having them simultaneously respond to the same probing packets during the probing phase. Multiple users' feedback is collected and processed together to determine data transmission beams for all users, rather than performing separate alignment procedures for each user, thereby reducing total alignment time while maintaining support for multiple users
Solution Approach 2:
The beam alignment is structured as a periodic process with distinct phases: a probing phase where scanning beams are transmitted and feedback is collected from multiple users, followed by a beam determination phase, and then a data transmission phase. This periodic structure allows the system to efficiently handle multiple users within each alignment cycle, balancing the need for multi-user support with alignment time constraints
3Measurement precision
If probing packets are sent to determine beam directions, then beam alignment accuracy improves, but feedback requirement increases
Solution Approach 1:
The system extracts only the essential information needed for beam alignment from the probing feedback, specifically identifying candidate directions and sufficient statistics for beam determination. Rather than requiring and processing complete channel state information or extensive feedback from users, the system extracts the minimal necessary data (feedback indicating received signal quality or direction information) to achieve accurate beam alignment, reducing feedback overhead while maintaining alignment accuracy
Data Source
AI summary
A method for transmitting data is provided. The method includes sending a probing packet using a scanning beam selected from a set of probing beams. The method further includes receiving feedback about the probing packet. The method also includes determining a data transmission beam based on the set of probing beams and the received feedback. The method additionally includes transmitting data using a multi-element antenna that is configured according to the determined data transmission beam.