Dynamic Receive Chain Adjustment for MIMO Power Savings
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Solution Overview
Problem
MIMO wireless communication systems face high power consumption due to excessive receive chains, even when receive diversity is not necessary, leading to inefficient power usage and increased costs.
Innovation Solution
A wireless device that dynamically adjusts the number of active receive chains based on the signal-to-noise ratio and modulation scheme of incoming packets, enabling only the minimum number required for reliable data reception, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple receive chains are enabled in a MIMO wireless communication system, then receive diversity and detection capability are improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of the number of active receive chains based on real-time channel conditions. The system evaluates signal quality metrics (such as SNR, RSSI, or channel state information) and adaptively enables or disables receive chains during operation. This dynamic approach allows the system to maintain optimal detection capability when channel conditions require diversity while reducing power consumption when channel conditions are good and fewer chains are sufficient.
Solution Approach 2:
The patent changes the operational parameters of the receive chains by adjusting the number of active chains based on channel quality parameters. When channel conditions are favorable (high SNR, strong signal), the system reduces the number of active receive chains from the maximum configuration to fewer chains, thereby reducing power consumption while maintaining adequate detection capability. When channel conditions deteriorate, the system increases the number of active chains to exploit receive diversity.
2Reliability
If all receive chains are enabled to receive the preamble, then initial signal detection is reliable, but unnecessary chains consume power during data reception
Solution Approach 1:
The patent performs preliminary evaluation of channel conditions during preamble reception using all available receive chains. The system uses the preamble phase to assess signal quality metrics and determine the minimum number of receive chains needed for reliable data reception. Based on this preliminary assessment, the system proactively adjusts the number of active receive chains before the data portion begins, ensuring that only the necessary number of chains remain active during data reception, thus avoiding unnecessary power consumption.
Solution Approach 2:
The patent segments the packet reception process into distinct phases (preamble reception and data reception) with different receive chain configurations. During preamble reception, all receive chains are enabled to ensure reliable initial signal detection and channel estimation. During data reception, the system transitions to a reduced configuration with only the minimum necessary receive chains active, determined by the preamble analysis. This segmentation allows the system to optimize for reliability during preamble detection while optimizing for power efficiency during data reception.
Data Source
AI summary
A wireless device that operates in accordance with the IEEE 802.11 standard receives the preamble of a packet with the highest number of receive chains enabled, thereby obtaining the highest gain, detection sensitivity and range. The wireless device determines a signal-to-noise ratio (SNR) in response to two different short training fields (STFs) in the preamble. The wireless device also determines a modulation and coding scheme (MCS) and a number of spatial streams (Nss) used to transmit the received packet in response to a signal field of the preamble. The wireless device uses these determined parameters to identify a minimum number of the receive chains required to reliably receive the packet. The wireless device uses only the identified minimum number of receive chains to perform channel estimation and receive the data portion of the packet.