MIMO User Terminal Rank Adaptation via SIR and Power Metrics
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Solution Overview
Problem
Current MIMO systems in 3G LTE face challenges in quickly and effectively adapting the rank of data streams due to the need for rapid phase adaptation and feedback, which affects the speed and quality of wireless communication.
Innovation Solution
A user terminal equipped with multiple antennas that dynamically chooses and signals the optimal rank for data transmission based on estimated received data rate, power consumption, and channel Signal to Noise Ratio (SIR), allowing for quicker and more informed switching between transmission ranks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phase adaptation is performed rapidly to enable dynamic rank switching in MIMO systems, then the adaptability of transmission modes is improved, but the feedback time requirement increases and system complexity increases
Solution Approach 1:
The system performs preliminary actions by having the UE continuously monitor downlink channel utilization and congestion levels in advance. The UE estimates received data rates for different transmission ranks and maintains this information ready, so when rank adaptation is needed, the decision can be made immediately based on pre-computed metrics rather than calculating from scratch at the moment of switching.
Solution Approach 2:
The invention implements a feedback mechanism where the UE monitors downlink channel conditions, estimates data rates for different ranks, and provides feedback to the network about its rank preferences and channel quality. This feedback loop enables the system to adapt transmission modes dynamically based on real-time channel conditions and UE capabilities, resolving the contradiction between rapid adaptation and feedback time requirements.
2Productivity
If the user terminal monitors downlink channel utilization and estimates data rates for different ranks, then the productivity of data transmission is improved, but the use of energy in the user terminal increases
Solution Approach 1:
The UE performs partial monitoring and estimation actions rather than continuous full-scale analysis. It monitors downlink channel utilization and estimates data rates selectively based on whether rank adaptation is actually needed, rather than continuously performing exhaustive measurements and calculations at all times. This partial action approach maintains productivity improvements while reducing unnecessary energy consumption.
3Productivity
If multiple antennas are equipped in user terminals to enable MIMO techniques, then the productivity of wireless communication is improved, but the device complexity increases
Solution Approach 1:
The multiple antennas in the UE are designed to serve multiple functions: they enable both MIMO transmission for high throughput and simultaneous channel quality measurement for rank adaptation decisions. The same antenna array used for receiving data streams also performs channel utilization monitoring and data rate estimation. This multi-functionality approach maintains productivity benefits while reducing overall device complexity by avoiding separate dedicated components.
Data Source
AI summary
A user terminal (115, 200) for a wireless communications system, equipped with at least two antennas (205, 206, 207) for the reception and/or transmission of traffic from a higher node (105). The user terminal (115, 200) is arranged to receive (210) said traffic in one or more data streams (S1, S2) i.e. with a rank of one or higher. The user terminal is arranged (215, 216, 220) to choose with which rank the higher node (105) should transmit the traffic to the user terminal (115, 200) on, and to also signal this choice to the higher node (105). The user terminal (115, 200) is arranged to base its choice of rank on the estimated received data rate at the user terminal for different transmission ranks, the estimated power consumption in the user terminal for different transmission ranks and the Signal to Noise ratio, SIR, of the channel at the UE.