Uplink-Only Relay Node Link Adaptation for Interference Control
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Solution Overview
Problem
In cellular communication systems, uplink/downlink imbalance issues arise due to the use of lower transmit power in relay nodes compared to macro base stations, leading to interference and challenges in determining which UEs should be connected via an uplink-only relay, as there is no downlink signal from the relay for UE measurement.
Innovation Solution
A method and device for an Uplink-Only Relay Node (UORN) that monitors the performance relation between direct and relayed uplink communications, indicating to the donor network node when conditions are met for connecting UEs, allowing for effective selection and adjustment of uplink link adaptation to optimize communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If relay nodes use lower transmit power to minimize impact on macro nodes, then interference to macro nodes is reduced, but uplink/downlink imbalance occurs and UEs cannot properly measure relay signals
Solution Approach 1:
The patent introduces a donor eNB as an intermediary that provides downlink reference signals to UEs through the relay node. This mediator enables UEs to measure relay signal quality without the relay node needing to transmit its own downlink reference signals, thus resolving the measurement problem while maintaining low relay transmit power
Solution Approach 2:
The donor eNB's downlink reference signals serve multiple functions: they enable UE measurement of relay link quality, provide synchronization for UEs connected via relay, and facilitate uplink power control. This multi-functionality eliminates the need for separate relay downlink reference signals
2Reliability
If uplink-only relay is deployed to extend uplink coverage, then uplink connectivity is improved, but there is no downlink signal from relay for UE measurement and cell selection
Solution Approach 1:
The donor eNB acts as an intermediary that provides downlink reference signals accessible to UEs through the relay node, enabling cell selection and measurement operations without requiring the uplink-only relay to transmit downlink signals
Solution Approach 2:
The patent extracts the downlink reference signal transmission function from the relay node and places it at the donor eNB, allowing UEs to perform measurements and cell selection based on donor eNB signals while connecting uplink through the relay
3Area of stationary object
If cell range expansion is used to extend underlay cell coverage, then underlay cell coverage is improved, but UEs served by macro node cause significant uplink interference to underlay node
Solution Approach 1:
The patent implements feedback mechanisms where the relay node monitors uplink interference levels and reports to the donor eNB, which then adjusts resource allocation and power control parameters to balance coverage extension with interference management
Solution Approach 2:
The system dynamically adjusts cell range expansion parameters, resource block allocation, and power control settings based on real-time interference conditions, allowing the network to adaptively balance coverage extension and interference mitigation
Data Source
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AI summary
Uplink-only relay and donor network node and methods therein for supporting connection of a UE in a cell associated with the network node to the uplink-only relay for uplink communication. The method in the uplink-only relay involves monitoring a relation, in terms of performance, between a direct uplink communication from the UE to the network node, and a potential relayed uplink communication from the UE to the network node via the UORN The method further comprises indicating to the network node when the relation fulfills a condition. The method in the network node involves receiving information, from the UORN, indicating a monitored UE for which a condition is fulfilled. The condition is related to a relation, in terms of performance, between a direct uplink communication from the UE to the network node, and a potential uplink communication relayed via the UORN. If the UE is to be relayed, the method further comprises indicating, to the UORN, that the UE will be relayed via the UORN; and further comprises: adjusting uplink link adaptation of the UE based on the received information.