Open-Loop MU-CoMP SCMA Transmission for Wireless Networks
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Solution Overview
Problem
Current CoMP systems face challenges with high overhead due to channel state information (CSI) feedback requirements and sensitivity to channel aging and feedback errors, especially in high-capacity and high-mobility wireless networks like 5G, ultra-dense networks, and moving networks.
Innovation Solution
Implementing open-loop multi-user coordinated multipoint (MU-CoMP) transmission using sparse code multiple access (SCMA), which selects a MU CoMP transmission mode and UE pairing scheme based on criteria, allocates SCMA layers, and configures control signaling to enable efficient data transmission without CSI feedback, leveraging channel quality indicator (CQI) feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If closed-loop CoMP or MU-MIMO schemes are used, then transmission performance is improved, but feedback overhead increases and system complexity increases
Solution Approach 1:
The patent extracts and removes the CSI feedback requirement from the CoMP transmission system by implementing open-loop operation. The system achieves CoMP transmission without requiring detailed channel state information feedback from users, thereby eliminating the feedback overhead while maintaining transmission performance through coordinated multi-point transmission and SCMA-based user multiplexing
Solution Approach 2:
The system enables users to perform self-interference cancellation and self-detection of their data streams from the composite received signal. Each user equipment (UE) independently detects its own data by utilizing known spreading codes and interference cancellation techniques, reducing the need for network-side processing and feedback mechanisms
2Reliability
If closed-loop CoMP or MU-MIMO schemes are used, then transmission performance is improved, but system complexity increases
Solution Approach 1:
The patent removes the complex CSI feedback processing chain from the system by operating in open-loop mode. The network controller and user equipment no longer need to perform complex channel estimation, CSI calculation, and feedback transmission, significantly reducing system complexity while maintaining transmission performance through coordinated transmission and SCMA-based separation
Solution Approach 2:
The patent replaces the complex mechanical feedback control system with a simpler open-loop system based on SCMA code-domain separation. Instead of using complex channel state information to dynamically adjust transmissions, the system relies on pre-designed sparse code sequences and interference cancellation at the receiver, reducing computational complexity
3Productivity
If SCMA is used for user multiplexing, then spectral efficiency is improved, but receiver complexity increases
Solution Approach 1:
Each user equipment performs self-interference cancellation and self-detection of its data stream from the composite received signal. The UE uses its known spreading code to identify and cancel its own transmitted signal components, and sequentially detects other users' signals by treating them as interference, thereby simplifying the overall receiver architecture while maintaining high spectral efficiency
Solution Approach 2:
The receiver sequentially detects and cancels user signals by treating previously detected signals as known quantities. After detecting one user's signal, the receiver discards it from the composite signal and recovers the next user's signal with reduced interference, progressively simplifying the detection process for each subsequent user
Data Source
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AI summary
Embodiments are provided to enable downlink open-loop multi-user coordinated multipoint (MU-CoMP) transmission using sparse code multiple access (SCMA). In an embodiment, a network controller selects, in a cluster of multiple transmission points (TPs) and multiple user equipment (UEs), a MU-CoMP with SCMA transmission mode and a UE paring scheme for data transmission from a set of TPs to a set of UEs. The controller schedules the set of UEs for data transmission from the set of TPs, including coordinating and allocating, for each TP in the set of TPs, a plurality of SCMA layers to the UEs in accordance with the selected MU CoMP with SCMA transmission mode. The controller also determines values for control signaling based on the scheduling. The control signaling configures the set of UEs to detect the data transmission from the TPs.