Base Station MU-MIMO Selection Using UE Mobility
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Solution Overview
Problem
Wireless communication systems face challenges in spectral efficiency, particularly in dense urban areas where many users require high throughput, leading to the need for additional spectrum, which is costly. Existing MIMO technologies can enhance spectral efficiency but struggle to optimally select UEs for MU-MIMO service due to limited MIMO layers and varying user conditions.
Innovation Solution
A base station employs a massive-MIMO antenna array and selects UEs for MU-MIMO service based on factors like low BLER, low power headroom, high power class, stationarity, and stable RF conditions to maximize spectral efficiency by optimizing the allocation of air-interface resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If additional licensed spectrum is configured to accommodate subscriber communication needs, then spectral efficiency and data rate are improved, but system cost increases
Solution Approach 1:
The patent combines multiple UEs into a MU-MIMO group, allowing concurrent transmissions to multiple UEs on the same time-frequency resources. This merging of users onto shared resources improves spectral efficiency without requiring additional spectrum, thereby avoiding increased system cost.
Solution Approach 2:
The patent introduces the spatial dimension through MIMO layers, enabling concurrent transmissions to multiple UEs in the same time-frequency resource by utilizing different spatial paths. This dimensional expansion allows the system to serve more users without additional spectrum allocation.
2Productivity
If MIMO layers are increased to serve more UEs concurrently, then spectral efficiency is improved, but MIMO layer availability is limited
Solution Approach 1:
The patent merges multiple UEs into a single MU-MIMO group that shares the available MIMO layers. Instead of requiring dedicated MIMO layers for each UE, multiple UEs are multiplexed onto the same layers through spatial separation, effectively increasing system capacity without increasing MIMO layer count.
Solution Approach 2:
The patent applies partial MU-MIMO service to selected UEs based on specific criteria (BLER, power headroom, mobility) rather than attempting to serve all UEs with full MU-MIMO. This selective approach maximizes the benefit from limited MIMO layers by concentrating resources on UEs that will provide the greatest spectral efficiency improvement.
3Productivity
If MU-MIMO service is provided to all UEs, then overall throughput is improved, but reliability decreases due to varying user conditions
Solution Approach 1:
The patent applies different service qualities to different UEs based on their local conditions. UEs are selectively admitted to MU-MIMO groups based on their BLER, power headroom, and mobility characteristics. This localized quality adjustment ensures that only UEs suitable for MU-MIMO service are included, maintaining reliability while improving overall throughput.
Solution Approach 2:
The patent uses feedback from UE conditions (BLER measurements, power headroom reports, mobility indicators) to dynamically determine MU-MIMO group composition. This feedback mechanism allows the system to adapt to changing user conditions and maintain reliable service by excluding UEs that would degrade MU-MIMO performance.
4Productivity
If conventional MIMO technologies are used, then basic spectral efficiency is achieved, but optimal UE selection for MU-MIMO service cannot be performed
Solution Approach 1:
The patent performs preliminary evaluation of UE conditions (BLER, power headroom, mobility) before admitting UEs to MU-MIMO groups. This preliminary action allows the system to pre-screen UEs and select only those that meet the criteria for successful MU-MIMO service, enabling optimal UE selection that conventional MIMO technologies lack.
Solution Approach 2:
The patent changes the selection parameters from basic signal strength metrics to comprehensive UE condition parameters including BLER, power headroom, and mobility indicators. This parameter transformation enables more sophisticated UE selection that adapts to varying user conditions and optimizes MU-MIMO group composition for maximum spectral efficiency.
Data Source
AI summary
A method and system for controlling application of MU-MIMO. The disclosure provides for considering a device's mobility as a basis to decide whether to provide the device with MU-MIMO service. For instance, a base station could determine which of the base station's served devices are each stationary or moving less than a threshold extent. And on at least that basis, the base station could select each such device to receive MU-MIMO service. Or faced with a choice between devices to receive MU-MIMO service, the base station could compare the devices' speed of movement and could select the devices that have lower speed of movement to receive MU-MIMO service.