gNB Coordinated UE-to-UE Beam Search for Link Stability
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Solution Overview
Problem
Establishing and maintaining direct device-to-device communication links between User Equipments (UEs) in a gNB cell is challenging due to changing environmental conditions, user mobility, and interference with other communication links, as existing methods do not efficiently coordinate beam search and link establishment.
Innovation Solution
A gNB determines the need for a direct link between UEs and initiates a beam search procedure by transmitting information to enable UEs to perform a beam search and report results, allowing the gNB to select optimal beams for establishing and maintaining a direct communication link.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If UEs establish direct device-to-device communication links using directional millimeter wave transmissions, then communication bandwidth and speed are improved, but link stability deteriorates due to user mobility and changing environmental conditions
Solution Approach 1:
The gNB performs preliminary beam search and beam pairing before establishing direct UE-to-UE links. The gNB transmits beam search reference signals and receives beam measurement reports from UEs in advance, determining optimal beam pairs before actual data transmission begins. This preliminary action ensures that when users move or environmental conditions change, the link can be quickly re-established using pre-identified alternative beams.
Solution Approach 2:
The system implements continuous feedback mechanisms where UEs report beam measurement results (such as RSRP values) back to the gNB. The gNB uses this feedback to dynamically adjust and update beam pair selections. When link quality degrades due to mobility or environmental changes, the feedback loop enables the gNB to identify and switch to better beam pairs, maintaining link stability while preserving high bandwidth utilization.
2Device complexity
If UEs perform beam search autonomously, then device complexity is reduced, but coordination efficiency with the gNB deteriorates
Solution Approach 1:
The gNB acts as an intermediary that coordinates beam search between UEs. Instead of UEs performing completely autonomous beam searches, the gNB transmits beam search reference signals, collects measurement reports, and determines optimal beam pairs. This intermediary role maintains relatively simple UE devices while achieving high coordination efficiency through centralized gNB control that optimizes overall system performance.
3Strength
If directional beams are used for millimeter wave transmission, then signal strength is improved, but interference with other communication links increases
Solution Approach 1:
The gNB assigns different spatial beam directions to different UE pairs, creating local quality differentiation in the electromagnetic space. Each direct UE-to-UE link uses specifically tailored beam pairs that concentrate signal energy in particular directions while minimizing interference in other directions. This local quality approach allows strong directional transmissions coexist by ensuring each beam is optimized for its specific spatial path rather than using uniform transmission patterns.
Solution Approach 2:
The gNB segments the overall communication space into multiple directional beam sectors and assigns different beam pairs to different UE pairs operating in the same time-frequency resources. By dividing the spatial domain into segmented beam directions, the system enables multiple simultaneous direct links without mutual interference, as each link operates in its own spatial segment defined by the assigned beam pair.
Data Source
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AI summary
Systems and methods establishing and maintain a direct User Equipment to User Equipment communication link in a gNB are disclosed. A gNB may determine that direct UE to UE link should be established in a cell. The gNB may transmit information to a first and second UE to enable a device to device beam search procedure. The first and second UE may perform the beam search and report the result to the gNB. The gNB may determine the appropriate beam for the first and second UE to establish a communication link.