C-RAN Uplink Reuse with Dynamic Combining Zone Assignment
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Solution Overview
Problem
Conventional techniques for implementing spatial uplink reuse in centralized radio access networks (C-RANs) are often simplistic or conservative, leading to limited opportunities for reuse and degradation of system performance due to inappropriate situations and UE movements.
Innovation Solution
A system comprising a controller and radio points that dynamically manage combining zones, schedule uplink transmissions, assign DM-RS cyclic shifts, and perform transmit power control to optimize uplink reuse, using a scheduler to allocate time-and-frequency resources and UE-specific DM-RS cyclic shifts to maximize distance and minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional simplistic or conservative techniques are used for implementing spatial uplink reuse, then device complexity is reduced, but productivity is limited due to fewer reuse opportunities
Solution Approach 1:
The system segments the radio points into different combining zones based on UE location and signal characteristics. Each UE is assigned a specific combining zone containing a subset of radio points, allowing independent management and optimization of reuse opportunities in different spatial regions without increasing overall system complexity
Solution Approach 2:
The system performs preliminary determination of minimum combining zones and signal zones for each UE based on pre-calculated reference signal received power (RSRP) measurements and pathloss compensation. This advance preparation enables rapid scheduling decisions and maximizes reuse opportunities without real-time complexity
2Productivity
If dynamic combining zone assignment is implemented to maximize uplink reuse, then productivity increases, but reliability may deteriorate due to inappropriate reuse situations and UE movements
Solution Approach 1:
The system dynamically adjusts combining zones based on real-time UE movements and signal conditions. The scheduler continuously monitors RSRP measurements and pathloss changes, reallocating UEs between combining zones and adjusting reuse assignments to maintain connection stability while maximizing productivity
Solution Approach 2:
The system implements feedback mechanisms where UEs report RSRP measurements and the scheduler monitors uplink transmission quality. This feedback enables the system to detect inappropriate reuse situations and UE movements, allowing corrective actions to maintain reliability while preserving reuse benefits
3Productivity
If aggressive spatial uplink reuse is implemented, then productivity increases, but object-affected harmful factors increase due to interference degradation
Solution Approach 1:
The system applies different reuse strategies to different spatial regions by creating location-specific combining zones. Each zone is optimized based on local interference conditions, allowing aggressive reuse where interference is low while maintaining conservative assignments where interference is high, thereby maximizing throughput without excessive interference
Solution Approach 2:
The system dynamically changes key parameters including combining zone composition, DM-RS cyclic shift assignments, and transmit power levels based on interference measurements. These parameter adjustments enable the system to optimize throughput while maintaining interference below degradation thresholds
4Productivity
If expanding combining zones is performed to maximize reuse, then productivity increases, but device complexity increases due to processing load and front-haul capacity requirements
Solution Approach 1:
The system implements partial combining zone expansion by selectively including only those radio points that provide significant performance improvement. Rather than expanding to include all available radio points, the system identifies and includes only the necessary subset, reducing processing load and front-haul requirements while maintaining productivity benefits
Data Source
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AI summary
This disclosure is directed to techniques for implementing uplink spatial reuse in a C-RAN and a system comprises a controller and a plurality of radio points, wherein the controller is configured to: implement a combining receiver to receive uplink transmissions from each UE, the combining receiver configured to combine data indicative of the uplink transmissions from each UEs as received at each radio point included in a combining zone assigned to that UE and communicated to the controller; assign, to each UE, a respective minimum combining zone comprising a respective minimum subset of the radio points for use as the combining zone of the combining receiver for receiving uplink transmission from that UE; assign, to each UE, a respective signal zone comprising a respective subset of the radio points that can be included in the combining zone of the combining receiver for receiving uplink transmission from that UE.