WLAN Packet Detection Using Single-Path Mixer and Comb Filter
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Solution Overview
Problem
Power consumption in wireless local area network (WLAN) transceivers is high due to the continuous waiting for packet arrival, leading to frequent battery replacements in IoT devices, as most current methods require substantial radio frequency (RF) analog front-end activity until a packet is detected.
Innovation Solution
A method and system for packet detection in WLAN transceivers that utilize a deliberate non-zero frequency offset in the local oscillator, allowing single-path processing to reduce power consumption by activating only one in-phase or quadrature path for detection, and subsequently activating both paths for decoding once a packet is detected, while avoiding aliasing through comb filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both in-phase and quadrature paths are activated continuously for packet detection, then detection reliability is improved, but power consumption increases
Solution Approach 1:
The packet detection process is segmented into two phases: initial detection using only the in-phase path, and subsequent processing using both in-phase and quadrature paths. This segmentation allows the system to use minimal resources for the majority of time (when no packet is present) while maintaining full capability when needed.
Solution Approach 2:
The system dynamically activates or deactivates the quadrature path based on detection results. The quadrature path remains inactive during initial detection and is only activated when a packet is detected, creating a dynamic power management strategy that adapts to actual communication conditions.
2Use of energy by moving object
If single-path processing is used for packet detection, then power consumption is reduced, but aliasing issues occur
Solution Approach 1:
The harmful aliasing components are extracted and removed from the downconverted signal using a filter before packet detection. This extraction of unwanted frequency components allows single-path processing to proceed without the detrimental effects of aliasing.
Solution Approach 2:
A filter is introduced as an intermediary component between the mixer and packet detector. This filter mediates the signal by removing image frequencies and aliasing components, enabling the subsequent single-path detection to operate cleanly without interference from unwanted spectral components.
3Speed
If RF analog front-end remains active continuously, then packet detection speed is improved, but battery life decreases
Solution Approach 1:
The RF analog front-end operates in a periodic manner, being fully active only during brief detection intervals and then entering a lower-power state. This periodic activation pattern maintains detection readiness while significantly reducing average power consumption compared to continuous operation.
Solution Approach 2:
The system performs preliminary packet detection using minimal circuitry before activating the full RF analog front-end. This preliminary action allows the system to screen for packet presence using low-power components, avoiding the need to keep high-power components continuously active.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces power consumption during packet detection, extending battery life by minimizing active circuitry during the receive mode and ensuring reliable packet detection without aliasing issues.
Implementation Method 1
A mixer is configured to mix the received signal with one of the in-phase and quadrature components of the local oscillator to produce a corresponding one of an in-phase downconverted signal and a quadrature phase down-converted signal
Data Source
AI summary
Systems and methods are provided for packet detection in a wireless local area network transceiver. An antenna is configured to receive a signal, having a carrier frequency. A mixer is configured to mix the received signal with one of the in-phase and quadrature components of the local oscillator to produce a corresponding one of an in-phase downconverted signal and a quadrature phase downconverted signal. A packet detector is configured to determine, from the one of the in-phase downconverted signal and the quadrature phase downconverted signal, if the signal contains a packet of data and instruct a set of components associated with an other of the in-phase and quadrature components of the local oscillator to activate to process the received signal.