Sequential Receive Combining in Radio Stripe Systems
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Solution Overview
Problem
Current distributed Massive Multiple-Input Multiple-Output (MIMO) systems face challenges with low performance due to lack of interference suppression in distributed processing and high fronthaul capacity requirements in centralized processing, limiting scalable solutions for coherent signal combining and interference cancellation.
Innovation Solution
Implementing sequential receive combining in radio stripe systems, where Antenna Processing Units (APUs) process signals sequentially during uplink data transmission, enabling local decision-making and interference suppression without requiring extensive CSI sharing or heavy fronthaul traffic, by transmitting effective channels and improved estimates between APUs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centralized processing is used to achieve coherent signal combining and interference suppression, then system performance is improved, but fronthaul capacity requirements increase significantly
Solution Approach 1:
The patent segments the receive combining process into distributed stages performed by multiple APUs sequentially. Each APU performs local signal processing and passes results to the next APU in the stripe, dividing the centralized processing task into manageable distributed segments that reduce fronthaul capacity requirements while maintaining interference suppression capabilities
Solution Approach 2:
The patent introduces a sequential processing dimension by arranging APUs in a stripe topology where signals are processed in sequence rather than all simultaneously at a central point. This temporal and spatial sequencing reduces the peak fronthaul capacity needed compared to fully simultaneous centralized processing
2Adaptability or versatility
If distributed processing is used to reduce fronthaul capacity requirements, then scalability is improved, but interference suppression capability deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where each APU receives effective channel information and improved data estimates from previous APUs in the stripe. This feedback loop enables each distributed APU to perform local interference suppression decisions based on accumulated information from other APUs, maintaining interference suppression capability while distributing the processing load
Solution Approach 2:
The patent applies preliminary receive combining and interference suppression at each APU in the stripe before passing results to the next APU. This preliminary action at distributed points maintains interference suppression capability while avoiding the need to transmit all raw signals to a centralized processor, thus improving scalability
3Measurement precision
If extensive CSI sharing is implemented to achieve optimal receive combining, then signal combining accuracy is improved, but system complexity and fronthaul traffic increase
Solution Approach 1:
The patent enables each APU to perform receive combining using only locally available channel state information and previously processed effective channel data from other APUs in the stripe. This local quality approach achieves accurate signal combining without requiring complex centralized CSI sharing infrastructure, reducing system complexity while maintaining combining accuracy
Data Source
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AI summary
The present disclosure relates to radio network communication. In one of its aspects, the present disclosure relates to a method, performed by a first APU, for sequential receive combining in a radio stripe system. The system comprises at least two APUs connected in series to a CPU and serves at least two UEs. According to the method, channel estimates for channels to said served UEs are received and based on these, a receive combining filter is determined. The receive combining filter is to be applied to received data signals. Thereafter, based on the obtained channel estimates and the determined receive combining filter, effective channels from said served UEs are determined. These represent the effective channel created after the receive combining filter being applied to each channel for said served UEs. The effective channels are transmitted from said served UEs to at least one subsequent second APU.