Interference Alignment Method for Uplink WLAN Channel Management
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Solution Overview
Problem
In wireless local area networks (WLANs), overlapping communication channels between basic service sets (BSSs) lead to interference, reducing network performance, as existing methods fail to effectively manage and minimize this interference.
Innovation Solution
The proposed interference alignment (IA) method involves an access point (AP) selecting an interference space, broadcasting information, and using a minimum mean square error (MMSE) based receiving filter to decode data from user terminals, while user terminals determine their transmission vectors based on signal-to-noise ratio (SNR) and leakage of interference (LIF) levels to minimize interference impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If each AP independently selects a channel using operator or channel allocation algorithm, then each AP can operate autonomously, but communication channels used by different BSSs overlap causing interference among adjacent BSSs
Solution Approach 1:
The patent converts interference from a harmful factor into a useful signal by applying interference alignment techniques. The AP receives signals containing both desired data and interference from adjacent BSSs, but uses the interference alignment method to align interference into a specific subspace, allowing separation of desired signals from interference through structured signal processing
Solution Approach 2:
The patent changes the parameter of channel selection from independent random selection to coordinated selection based on interference space information. The AP broadcasts interference space parameters to user terminals, which then select transmission channels and vectors that align interference constructively, transforming the channel selection process from a source of interference to a mechanism for interference management
2Object-affected harmful factors
If interference alignment method is applied to manage overlapping channels, then interference among adjacent BSSs is reduced, but system complexity increases due to interference space selection and MMSE filter implementation
Solution Approach 1:
The patent performs preliminary action by having the AP broadcast interference space information to user terminals before actual data transmission occurs. This allows user terminals to pre-calculate transmission vectors and select appropriate channels that will align interference constructively, so that when data transmission happens, the interference alignment is already established, reducing real-time processing complexity
Solution Approach 2:
The patent introduces an intermediary mechanism through the use of pilot signals and interference space parameters that mediate between the AP and user terminals. These intermediaries carry information about the interference environment, enabling coordinated interference alignment without requiring complex direct communication between all devices, thus managing system complexity through structured information exchange
Data Source
AI summary
An interference alignment (AI) method for an uplink in a wireless local area network (WLAN) system, an access point (AP) and a user terminal for performing the same, and the AP that may select an interference space, broadcast information on the selected interference space, select a user terminal to be assigned a data transmission opportunity based on leakage of interference (LIF) information received from at least one user terminal, receive data from the user terminal, and decode the data using a minimum square error (MMSE) based receiving filter.