OFDM Signal Weighting for MU-MIMO Interference
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Solution Overview
Problem
Wireless local area networks (WLANs) face limitations in high-density environments due to interference and inefficiencies in transmitting and receiving multiple signals simultaneously, leading to reduced throughput and reliability, as they lack effective mechanisms for uplink multi-user MIMO (MU-MIMO) and efficient channel estimation.
Innovation Solution
A method and system that utilize multiple antennas to receive and process orthogonal frequency division multiplexing (OFDM) signals from multiple devices, determining subcarrier vectors and weighting vectors to isolate individual signals from interference, enabling simultaneous communication and improving MU-MIMO capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple WLAN devices transmit simultaneously using distributed scheduling, then network capacity increases, but signal interference increases and information is lost
Solution Approach 1:
The patent introduces an intermediary mechanism (weighting vector computation and application) between signal transmission and reception. The access point computes weighting vectors based on channel state information and applies them to received signals to separate simultaneous transmissions from multiple client devices, enabling reliable reception despite simultaneous transmissions that would otherwise cause interference
2Reliability
If WLAN devices access the medium less frequently to reduce interference, then information loss decreases, but throughput efficiency decreases
Solution Approach 1:
The patent enables continuous useful action by allowing multiple client devices to transmit simultaneously without requiring them to wait for sequential access. The access point continuously receives and processes multiple simultaneous signals using weighting vectors, eliminating the need for devices to reduce their transmission frequency while maintaining reliable communication
3Productivity
If DL MU-MIMO is implemented without UL MU-MIMO, then downlink capacity increases, but channel information gathering efficiency decreases
Solution Approach 1:
The patent implements self-service by enabling client devices to autonomously perform channel sounding and report channel state information back to the access point using uplink transmissions. This allows the access point to gather necessary channel information for downlink MU-MIMO operations without requiring dedicated downlink feedback mechanisms, significantly reducing the time and overhead for channel information gathering
Data Source
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AI summary
Embodiments of the present invention relate to methods and systems for simultaneous communication with multiple wireless communication devices. In some embodiments, a method for simultaneous communication with multiple wireless communication devices includes receiving, using a plurality of antennas at a first wireless station, a plurality of packets, comprised of orthogonal frequency division multiplexing (OFDM) wireless signals, transmitted simultaneously from a plurality of other wireless stations wherein each of the simultaneously transmitted packets includes a plurality of frequency tones, frequency domain transform the received packets, grouping frequency domain transform outputs for each subcarrier, determining a difference between subcarrier groups formed over different sample sets, and determining a set of weights for each subcarrier, wherein the weights are selected such that the first wireless station can at least one of detect or demodulate the received plurality of packets.