MIMO Antenna Selection via Embedded Sounding Frames
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Solution Overview
Problem
Existing MIMO wireless local area networks face increased hardware complexity and cost due to the need for multiple RF chains, and conventional antenna/beam selection methods introduce overhead through explicit signaling in both MAC and PHY layers, which is undesirable.
Innovation Solution
A method for selecting antennas in MIMO WLANs that uses consecutive sounding packets with a high throughput control field to initiate antenna selection, allowing channel matrix estimation and subset selection solely at the MAC layer, reducing overhead and maintaining efficient data transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple antennas are used in MIMO systems, then system capacity and diversity are improved, but hardware complexity and cost increase due to multiple RF chains
Solution Approach 1:
The patent segments the antenna set into multiple subsets, where each subset is associated with a separate RF chain. This allows the system to use multiple antennas for diversity and capacity while requiring fewer RF chains than the total number of antennas, thus reducing hardware complexity and cost while maintaining system capacity and diversity benefits
Solution Approach 2:
The patent employs partial antenna activation where not all antennas are simultaneously connected to active RF chains. By selectively activating subsets of antennas based on channel conditions and using antenna selection training, the system achieves the necessary diversity and capacity with fewer than N RF chains for N antennas, reducing hardware requirements
2Measurement precision
If explicit signaling is used for antenna/beam selection training, then antenna selection accuracy is improved, but overhead increases in MAC and PHY layers
Solution Approach 1:
The patent merges the antenna selection training process with existing data transmission by embedding training sequences within data packets. This integration allows the system to perform channel estimation and antenna selection without requiring separate dedicated training frames, thereby maintaining measurement precision while significantly reducing overhead in both MAC and PHY layers
Solution Approach 2:
The patent makes data packets serve multiple functions: they simultaneously carry user data and embedded training sequences for channel estimation and antenna selection. This multi-functionality eliminates the need for separate training overhead, achieving both accurate antenna selection and efficient data transfer in a unified transmission mechanism
Data Source
AI summary
A method selects antennas in a multiple-input, multiple-output (MIMO) wireless local area network (WLAN) that includes a plurality of stations, and each station includes a set of antennas. Plural consecutive packets, received at a station, include plural consecutive sounding packets. Each sounding packet corresponds to a different subset of the set of antennas, and at least one of the plural consecutive packets includes a high throughput (HT) control field including a signal to initiate antenna selection and a number N indicative of a number of sounding packets which follow the at least one packet including the HT control field and which are to be used for antenna selection. A channel matrix is estimated based on a characteristic of the channel as indicated by the received N sounding packets, and a subset of antennas is selected according to the channel matrix. Station and computer program product embodiments include similar features.