Link Adaptation for Non-Collocated Antennas
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Solution Overview
Problem
Current multi-access wireless communication networks, particularly in LTE standards, face suboptimal link adaptation due to the assumption of equal transmit powers from non-collocated and power-imbalanced base station antennas, leading to inefficient data rate selection for user equipment.
Innovation Solution
The network signals the actual signal powers of non-collocated and power-imbalanced base station antennas to the user equipment, allowing it to determine a modified transmit precoder and Channel Quality Indicator (CQI) for improved link adaptation, accounting for power imbalances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the network assumes equal transmit powers from non-collocated base station antennas, then the system complexity is reduced and ease of operation is improved, but link adaptation accuracy deteriorates and data rate optimization is suboptimal
Solution Approach 1:
The patent changes the parameter assumption from equal transmit powers to actual measured transmit powers. The network signals actual power values P1 and P2 to the UE, which then uses these parameters in CQI calculation to determine accurate link adaptation, resolving the contradiction between operational simplicity and accuracy.
2Measurement precision
If the network signals actual signal powers of non-collocated base station antennas to user equipment, then link adaptation accuracy is improved, but device complexity and processing requirements increase
Solution Approach 1:
The network performs preliminary action by signaling the actual transmit power values P1 and P2 to the UE before the UE performs CQI calculation. This allows the UE to use pre-provided power parameters rather than performing complex power measurements or calculations, reducing device complexity while maintaining accuracy.
3Adaptability or versatility
If the network uses non-collocated and power-imbalanced base station antennas, then network coverage and flexibility are improved, but link adaptation performance deteriorates due to power imbalance assumptions
Solution Approach 1:
The patent applies local quality by allowing different transmit power characteristics for different base station antennas (P1 for first antenna, P2 for second antenna). The UE receives and uses these location-specific power values in its CQI determination, enabling accurate link adaptation for each antenna's local characteristics while maintaining overall network flexibility.
Data Source
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AI summary
Systems and methods for efficient link adaptation in multi-access wireless communication networks, including link adaptation in scenarios with non-collocated and/or power imbalanced base station transmit antennas are provided. In an embodiment, an indication of signal powers of the transmit antennas is signaled by the network to the user equipment (UE) when the UE is configured for logical antenna ports using non-collocated and/or power imbalanced transmit antennas. The UE can use the indication of signal powers in determining the Precoding Matrix Indicator (PMI) and the Channel Quality Indicator (CQI), resulting in higher accuracy link adaptation.