WLAN Subcarrier Allocation for Power Efficiency
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Solution Overview
Problem
WLAN systems face inefficiencies in power usage and modulation order due to the need for full bandwidth allocation, especially in outdoor environments with varying channel quality, leading to wasted transmit power and restricted high-order modulation.
Innovation Solution
A method for allocating WLAN channel resources by selecting subcarriers with channel quality greater than or equal to a judgment threshold, reducing power waste and allowing higher modulation orders by only using subcarriers with sufficient channel quality for data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If full bandwidth allocation is used in OFDM-based WLAN systems, then the coverage can be extended, but transmit power is greatly wasted in subchannels with very poor channel quality
Solution Approach 1:
The patent segments the frequency spectrum into multiple subchannels and evaluates each subchannel's quality independently. By dividing the bandwidth into smaller units, the system can selectively activate only those subchannels with acceptable quality thresholds, avoiding power waste in poor-quality subchannels while maintaining coverage in good-quality regions.
Solution Approach 2:
The patent applies local quality assessment by evaluating channel quality metrics (such as signal-to-noise ratio) for each individual subchannel. This allows the system to make localized decisions about which subchannels to use for data transmission, ensuring that power is only expended on subchannels where it will be effective, thereby resolving the contradiction between coverage extension and power efficiency.
2Area of stationary object
If data is transmitted in subchannels with very poor channel quality, then coverage is maintained, but higher order modulation cannot be achieved due to pull-down effect
Solution Approach 1:
By segmenting the bandwidth into subchannels and independently evaluating each one, the system can identify and select only those subchannels with sufficient quality to support higher-order modulation schemes. This segmentation enables the system to achieve high spectral efficiency in good subchannels without being constrained by poor subchannels.
Solution Approach 2:
The patent dynamically changes modulation parameters based on subchannel quality assessments. For subchannels with poor quality, the system may use lower-order modulation or exclude them entirely, while for subchannels with good quality, higher-order modulation is employed. This adaptive parameter adjustment resolves the contradiction by allowing high modulation orders where possible while maintaining coverage elsewhere.
3Loss of energy
If subcarrier selection based on channel quality threshold is implemented, then power efficiency and modulation order are improved, but system complexity increases due to channel quality measurement and subcarrier allocation
Solution Approach 1:
The receiving device performs channel quality measurements and determines which subcarriers meet the quality threshold, then feeds back this information to the transmitting device. This self-service approach allows the system to achieve intelligent subcarrier selection without requiring complex processing at the transmitter, as the receiving device leverages its local channel knowledge to make the selection decisions.
Solution Approach 2:
The patent implements a feedback mechanism where the receiving device measures channel quality, identifies suitable subcarriers, and communicates this information back to the transmitting device. This feedback loop enables the transmitter to allocate power and modulate data efficiently on selected subcarriers without needing to independently measure or calculate channel quality, thereby reducing transmitter complexity while achieving power efficiency gains.
Data Source
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AI summary
The present invention provides a method and device for allocating WLAN channel resources and a wireless local area network communication system. The method includes: obtaining subcarrier allocation information, where the subcarrier allocation information is used to identify a subcarrier or a subcarrier group used to bear data, where channel quality of a subchannel where the subcarrier or the subcarrier group is located is greater than or equal to a judgment threshold; and sending data on the subcarrier according to the subcarrier allocation information. The present invention reduces a waste of transmit power of a station, and can increase a modulation order because no restriction is imposed by pull-down of a subchannel with very poor channel quality