Composite Sounding for MIMO Beamforming in Wireless Home Networks
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Solution Overview
Problem
Existing wireless access points (WAPs) face limitations in communicating with stations that do not support sounding feedback matching their capabilities, leading to suboptimal signal strength and throughput due to incomplete channel characterization.
Innovation Solution
A WAP apparatus with a sounding mode module, sounding matrix generator, aggregator, gain normalizer, and beamforming expansion module initiates either single or composite soundings based on feedback mismatch, generating linearly independent spatial mapping matrices to aggregate partial feedbacks into a full beamforming matrix for enhanced communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a WAP uses a single sounding approach, then the device complexity is low, but the measurement precision of channel characterization is insufficient when station capabilities do not match WAP capabilities
Solution Approach 1:
The patent segments the sounding process into multiple independent soundings, each targeting a subset of spatial streams that the station can handle. Instead of attempting a single comprehensive sounding that would exceed station capabilities, the WAP divides the channel characterization into multiple manageable parts, collecting feedback from each segment and combining them to achieve complete channel knowledge.
Solution Approach 2:
The patent employs partial action by performing multiple soundings that collectively cover the full channel space. Each individual sounding provides partial channel information, but when aggregated across multiple soundings with different spatial mapping matrices, they provide complete channel characterization equivalent to or exceeding what a single comprehensive sounding would achieve.
2Measurement precision
If a WAP performs multiple soundings to characterize the full channel, then the measurement precision improves, but the loss of time increases due to multiple feedback cycles
Solution Approach 1:
The patent applies preliminary action by having the WAP determine the station's sounding feedback capabilities before initiating the sounding process. Based on this preliminary capability assessment, the WAP pre-plans the appropriate number and configuration of soundings required, optimizing the trade-off between measurement precision and time consumption before the actual sounding begins.
Solution Approach 2:
The patent implements dynamics by adapting the number and configuration of soundings based on the specific capabilities of each station. Rather than using a fixed sounding approach for all stations, the system dynamically adjusts the sounding strategy to match each station's feedback capabilities, thereby optimizing the balance between achieving complete channel characterization and minimizing time loss.
3Adaptability or versatility
If a WAP uses composite soundings with multiple spatial mapping matrices, then the adaptability to stations with constrained capabilities improves, but the device complexity increases due to matrix generation and aggregation
Solution Approach 1:
The patent achieves universality by designing a sounding framework that can accommodate stations with varying feedback capabilities. The same composite sounding mechanism works for both stations with full capabilities and those with constrained capabilities, automatically adapting to each station's specific limitations through the capability determination step and appropriate configuration of spatial mapping matrices.
Solution Approach 2:
The patent introduces spatial mapping matrices as intermediaries that enable the WAP to communicate effectively with stations of different capabilities. These matrices act as a mediator between the WAP's multi-antenna system and the station's limited feedback capacity, transforming the channel characterization process into a form that the station can handle while still capturing the essential channel information.
4Measurement precision
If a WAP aggregates partial feedbacks from multiple soundings, then the measurement precision of full beamforming matrix improves, but the loss of information may occur during feedback aggregation
Solution Approach 1:
The patent employs feedback by having the station provide sounding feedback for each individual sounding, and then using this feedback iteratively to construct the complete beamforming matrix. The feedback mechanism ensures that information from each partial sounding is captured and utilized, with the aggregation process designed to preserve and combine this information rather than lose it.
Solution Approach 2:
The patent applies merging by combining the partial feedback information from multiple soundings into a complete beamforming matrix. The aggregation process integrates the channel information obtained from each sounding, using the spatial mapping matrices to properly align and combine the partial feedbacks, thereby reconstructing the full channel characterization without information loss.
Data Source
AI summary
A WAP including: a sounding mode module, a sounding matrix generator, a sounding aggregator, a gain normalizer and a beamforming expansion module. The sounding mode module determines whether a number of communication streams supported by the WAP matches the number of streams contained in a sounding response from a station, and initiates a composite set of soundings when those capabilities do not match. The sounding matrix generator generates linearly independent spatial mapping matrices each associated with a corresponding one of the set of composite soundings and at least one reference SMM. The sounding aggregator aggregates partial sounding feedback matrices received from the targeted station node in response to the composite soundings. The gain normalizer normalizes the partial sounding feedback matrices utilizing the reference SMM. The beamforming expansion module expands the aggregated sounding feedback matrices into a full beamforming matrix for spatially mapping downlink communications.