Coordinated AP Channel Estimation via Orthogonal Training Fields
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Solution Overview
Problem
Current Wi-Fi networks using IEEE 802.11 standards face challenges in coordinating multiple access points (APs) for simultaneous communication with client devices, leading to interference and degraded performance, especially at the edge of coverage areas, due to the lack of efficient channel estimation and dynamic coordination mechanisms.
Innovation Solution
The implementation of a coordinated AP transmission system that uses orthogonal training fields, overlay matrices, and cyclic shift diversity to enable channel estimation and separate signals in time and code domains, allowing multiple APs to jointly transmit data to a single station, thereby improving channel state information exchange and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple access points transmit simultaneously to a station, then network utilization and communication reliability are improved, but signal interference and channel estimation difficulty increase
Solution Approach 1:
The patent segments the training fields from different access points using orthogonal codes, allowing the station to separately estimate channels from each AP. This code-domain segmentation enables simultaneous transmissions while maintaining distinguishable training sequences for individual channel estimation.
Solution Approach 2:
The patent introduces orthogonal training fields as an intermediary mechanism that mediates between multiple AP transmissions. These orthogonal training fields act as a separating layer that allows the station to extract individual channel information from composite signals containing transmissions from multiple APs.
2Reliability
If multiple access points transmit simultaneously to a station, then communication reliability is improved, but channel estimation accuracy deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the composite signal into separable components through orthogonal coding. Each AP's training field is coded orthogonally, enabling the station to segment and estimate each channel independently despite simultaneous transmissions.
Solution Approach 2:
The patent changes the parameter of training field orthogonality to enable separation. By ensuring training fields from different APs are orthogonal in the code domain, the station can maintain accurate channel estimation for each AP even when receiving simultaneous transmissions.
3Measurement precision
If orthogonal training fields are used for channel estimation, then channel state information accuracy is improved, but system complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-defining orthogonal codes for training fields before transmission. This pre-planned orthogonal structure simplifies the receiver's task, as the station can directly apply known orthogonal codes to separate and estimate channels without complex signal processing.
Solution Approach 2:
The patent uses parameter changes by transitioning to orthogonal coded training fields, which transforms the channel estimation problem into a simpler correlation-based separation task. This parameter change from non-orthogonal to orthogonal training fields improves accuracy while managing complexity through mathematical orthogonality properties.
Data Source
AI summary
This disclosure describes systems, methods, and devices related to channel estimation for coordinated access point (AP) transmissions. A device may identify of one or more access points associated with a coordinated basic service set. The device may determine to transmit one or more packets to a station device in coordination with the one or more access points. The device may determine one or more first training fields associated with one or more antennas of the device. The device may cause to send the one or more first training fields to the station device on one or more first communication links between the device and the station device.