Wireless LAN Wake-up Packet Transmission Using OOK Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Next-generation wireless LAN systems face challenges in improving spectrum efficiency and area throughput, especially in dense environments with multiple access points and stations, and require efficient low-power communication methods to reduce interference and power consumption.
Innovation Solution
The method involves transmitting a wake-up packet using an OOK scheme and symbol repetition in a wireless LAN system, where the wake-up packet is generated by applying the OOK modulation method and repeated symbols to extend the symbol length, allowing for low-latency communication and reducing power consumption in the receiving device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional wake-up packet transmission methods are used, then the receiving device can detect wake-up signals, but power consumption is high and communication range is limited
Solution Approach 1:
The patent changes the modulation parameter from conventional QPSK to OOK (On-Off Keying), which simplifies the receiving device to use only an envelope detector instead of a complex coherent demodulator. This parameter change dramatically reduces power consumption while maintaining communication reliability through the inherent robustness of OOK modulation in low-SNR environments.
Solution Approach 2:
The patent extends the symbol length by repeating the same symbol multiple times (e.g., 4 repetitions), effectively adding a time dimension to the communication. This symbol repetition technique increases the energy per information bit without increasing transmission power, thereby improving communication reliability while keeping the receiving device power consumption low.
2Measurement precision
If symbol length is extended to improve communication reliability, then detection accuracy improves, but transmission time increases
Solution Approach 1:
The patent uses symbol repetition (e.g., 4 repetitions of the same symbol) to extend the effective symbol length, which improves detection accuracy by providing more integration time for the envelope detector. While this does increase transmission time, the use of OOK modulation ensures that each repeated symbol carries the same information efficiently, minimizing the time penalty compared to using more complex modulation schemes with longer constitutive symbols.
3Use of energy by moving object
If OOK scheme with symbol repetition is used, then power consumption is reduced and detection accuracy is improved, but spectrum efficiency decreases
Solution Approach 1:
The patent changes the modulation parameter to OOK, which uses only two signal states (present and absent) instead of multiple phases or amplitudes. This parameter change simplifies the receiving device and reduces power consumption, but inherently reduces spectrum efficiency compared to higher-order modulations. The patent accepts this trade-off as the primary goal is low-power operation in wake-up scenarios where data transmission rate is not critical.
Solution Approach 2:
The patent compensates for the spectrum efficiency loss by using symbol repetition in the time domain. Instead of trying to pack more information into each symbol (which would require more complex modulation), the patent repeats the same symbol multiple times, effectively trading frequency-domain efficiency for time-domain robustness. This approach maintains low power consumption while achieving reliable communication.
Data Source
AI summary
A method and an apparatus for transmitting a wakeup packet in a wireless LAN system are proposed. Particularly, a transmission device configures a wakeup packet and transmits the wakeup packet to a receiving device. The wakeup packet includes a sequence configured with first information and second information by applying an OOK method. The first information and the second information are configured with an on-signal or an off-signal. The on-signal is transmitted through a first symbol, which is generated by applying a first sequence to K consecutive subcarriers in the 20 MHz band and performing 64-point IFFT. The off-signal is transmitted through a second symbol, which is generated by applying a second sequence to K consecutive subcarriers in the 20 MHz band and performing 64-point IFNT. The first information and the second information are transmitted through a third symbol in which the first symbol or the second symbol is repeated.