Integer Forcing MU-MIMO Receiver Filter Design
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Solution Overview
Problem
Current MIMO wireless communication systems face challenges in efficiently managing inter-symbol interference, particularly in multi-user scenarios, where existing linear schemes offer low complexity but inferior performance, and nonlinear schemes are too complex, especially for uplink/downlink Multi-User MIMO communication.
Innovation Solution
The Integer Forcing (IF) scheme is applied to Multi-User Multiple-Input and Multiple-Output (MU-MIMO) communication, involving inter-cell interference control, IF filter setting, and Modulation and Coding Scheme (MCS) allocation methods at the base station and user equipment, enabling effective decoding of desired and interference signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nonlinear schemes (ML method, sphere decoding) are used to resolve inter-symbol interference, then performance is excellent, but complexity sharply increases especially when the number of antennas increases
Solution Approach 1:
The patent segments the interference resolution process by separating the detection of desired signal from interference signal. The receiver first detects the desired signal using a linear filter, then separately detects and subtracts the interference signal using integer forcing constraints. This segmentation allows achieving near-optimal performance without the exponential complexity of joint ML detection.
Solution Approach 2:
The patent changes the parameter constraints by imposing integer forcing constraints on the effective channel matrix. By requiring that the product of the effective channel matrix and the channel estimation error matrix equals an integer matrix, the system transforms the continuous optimization problem into a discrete one that can be solved with reduced complexity while maintaining high performance.
2Device complexity
If linear schemes (ZF, MMSE methods) are used to resolve inter-symbol interference, then complexity is relatively low, but performance is inferior to nonlinear schemes
Solution Approach 1:
The patent introduces an intermediary integer forcing constraint as a mediator between the simple linear filtering and the optimal nonlinear detection. This constraint acts as a bridge that guides the linear detector to achieve performance closer to nonlinear schemes by enforcing integer constraints on the effective channel matrix, thereby improving performance without significantly increasing complexity.
3Reliability
If IF scheme is applied to UL/DL MU-MIMO communication, then performance close to ML method is achieved with complexity similar to linear schemes, but the method has not yet been proposed
Solution Approach 1:
The patent makes the IF scheme universal for both uplink and downlink MU-MIMO communications by formulating a unified receiver structure that can handle multiple users in both transmission directions. The same integer forcing principle is applied regardless of whether the scenario is UL or DL, enabling broad applicability while maintaining the favorable complexity-performance tradeoff.
Data Source
AI summary
The present disclosure relates to a 5G or pre-5G communication system for supporting a higher data transmission rate successive to a 4G communication system such as LTE. The present disclosure provides a communication method of a Base Station (BS) using an Integer Forcing (IF) scheme in a Multi-User Multiple-Input and Multiple-Output (MU-MIMO) communication system, the method including: receiving a reception signal including a desired signal transmitted from at least one User Equipment (UE) served by the BS and an interference signal transmitted from at least one UE served by a neighboring BS; determining an IF filter considering the interference signal based on information on the interference signal received from the neighboring BS; filtering the reception signal using the determined IF filter; and detecting or decoding at least one of the desired signal and the interference signal using the filtered reception signal.