Linear Pre-coding for Inter-cell Interference in Multi-user MIMO Networks
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Solution Overview
Problem
Multi-user MIMO networks face significant challenges in reducing inter-cell interference due to asynchronous signal arrival at mobile stations, which degrades network performance, especially in high data rate environments, and existing solutions like joint pre-coding are complex and inefficient.
Innovation Solution
The implementation of linear pre-coding methods in cooperative base station networks that account for timing advance inaccuracies and asynchronous interference, using jitter statistic-aware pre-coders to synchronize signals and minimize interference, along with joint Wiener filtering and joint leakage suppression techniques to optimize information rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If joint pre-coding optimizations among coordinated base stations are implemented, then inter-cell interference is reduced, but network complexity increases significantly
Solution Approach 1:
The patent segments the interference mitigation problem by treating desired signals and interfering signals separately. The pre-coding process divides signals into synchronous components (desired) and asynchronous components (interference), applying different handling strategies to each segment to reduce overall complexity while maintaining effectiveness.
Solution Approach 2:
The patent changes the timing parameter by introducing timing advance adjustments to synchronize desired signals from multiple base stations. By modifying the transmission timing parameter, the system transforms asynchronous interference into a manageable form that can be processed with reduced complexity linear pre-coding.
2Device complexity
If linear pre-coding is used among cooperative base stations, then complexity requirements are reduced, but asynchronous interference from different base stations cannot be eliminated
Solution Approach 1:
The patent applies preliminary anti-action by using timing advance to pre-synchronize desired signals before transmission. This preliminary synchronization action counteracts the asynchronous nature of signals from different base stations, reducing the harmful effects of asynchronism before the linear pre-coding process begins.
Solution Approach 2:
The patent converts the harmful asynchronous interference into a beneficial structure by modeling it as a known statistical process. The receiver uses this knowledge to design detectors that exploit the statistical properties of asynchronous interference, transforming what was previously a harmful unpredictable factor into a manageable characterized phenomenon.
3Manufacturing precision
If timing advance is used to synchronize signal arrival at mobile stations, then synchronous reception is achieved, but timing advance inaccuracies cause jitter and performance degradation
Solution Approach 1:
The patent applies beforehand cushioning by designing the system to tolerate timing advance inaccuracies. The pre-coding and receiver detection processes are specifically designed to handle the expected level of jitter, cushioning against performance degradation before it occurs by accounting for timing errors in the system design rather than attempting to eliminate them completely.
4Ease of manufacture
If conventional radio resource management techniques are used, then implementation is simple, but spectral efficiency gains are limited in multi-user cellular networks
Solution Approach 1:
The patent merges multiple techniques by combining linear pre-coding at the transmitter with joint detection at the receiver. This combination achieves spectral efficiency gains comparable to much more complex nonlinear techniques while maintaining relative simplicity in implementation, effectively merging the advantages of different approaches.
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AI summary
A method transmits and receives signals in a cooperative, multi-user, multi-input, multi-output network. The network includes base stations (BSs) and mobile stations (MSs). Each BS has at least two antennas, and each MS has at least one antenna. At a first base station and a second base station using linear pre-coding matrices, a plurality of data streams are jointly pre-coded to produce first signals and second signals. The first signals are transmitted synchronously from the first BS and the second BS to a first MS, and the second signals are transmitted synchronously from the first BS and the second BS to a second MS, and in the first signal and the second signal are asynchronous with respect each other.