Low-Frequency Time Synchronization for High-Frequency WLAN Scheduling
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Solution Overview
Problem
In wireless local area networks (WLANs) using high frequency bands like millimeter waves, the carrier sense multiple access with collision avoidance (CSMA/CA) mechanism leads to high power consumption due to prolonged signal detection times, as receivers cannot determine the exact time of signal transmission.
Innovation Solution
Implementing a communication method that coordinates between low and high frequency bands for dynamic scheduling, where time synchronization and resource allocation are managed through a lower frequency domain to reduce power consumption and delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CSMA/CA mechanism is used for high frequency band communication, then channel access control is achieved, but receiver power consumption increases due to prolonged signal detection time
Solution Approach 1:
The patent applies preliminary action by having the transmitter send a signal indication before the actual data transmission. This indication tells the receiver exactly when to expect the signal, allowing the receiver to enter low-power state during intervals and only wake up at the indicated time. This resolves the contradiction by maintaining reliable channel access control while dramatically reducing the receiver's active detection time and power consumption.
Solution Approach 2:
The patent introduces a signal indication as an intermediary element between the transmitter and receiver. This indication acts as a mediator that carries timing information, enabling the receiver to synchronize with the transmitter without continuous monitoring. The intermediary resolves the contradiction by providing the necessary control information while allowing the receiver to minimize its active listening time, thus reducing power consumption while maintaining reliable communication.
2Reliability
If continuous channel detection is performed to ensure reliable communication, then communication reliability is improved, but data transmission delay increases
Solution Approach 1:
The transmitter performs preliminary action by sending the signal indication in advance, which contains the timing information for the upcoming transmission. This allows the receiver to prepare and switch to active state at the precise moment of transmission, eliminating the need for continuous detection. The contradiction is resolved by achieving communication reliability through advance notification while minimizing detection time and reducing transmission delay.
Solution Approach 2:
The patent applies skipping by allowing the receiver to skip the continuous detection phase and go directly to targeted detection at the indicated time. Instead of continuously monitoring the channel, the receiver uses the signal indication to jump directly to the relevant transmission moment. This resolves the contradiction by maintaining reliability through precise timing while rushing through the detection process to minimize delay.
3Productivity
If dynamic scheduling is implemented between low and high frequency bands, then resource utilization improves, but system complexity increases
Solution Approach 1:
The patent applies segmentation by separating the control plane (low frequency band) from the data plane (high frequency band). The low frequency band handles signaling and scheduling information, while the high frequency band is dedicated to high-speed data transmission. This segmentation resolves the contradiction by improving resource utilization through coordinated multi-band operation while managing complexity through functional separation, as each band has a specialized role.
Solution Approach 2:
The patent applies multi-functionality by using the low frequency band for multiple purposes: control signaling, scheduling information transmission, and coordination between bands. This universal use of the low frequency control channel resolves the contradiction by enabling efficient resource allocation across both bands without requiring separate complex control mechanisms for each band, thus improving overall resource utilization while containing system complexity.
Data Source
AI summary
An access point (AP) sends time synchronization information through a first frequency domain resource, where the time synchronization information indicates a start time of a first superframe. The AP communicates with a station (STA) in the first superframe through a second frequency domain resource in a dynamic scheduling manner, where a frequency corresponding to the first frequency domain resource is lower than a frequency corresponding to the second frequency domain resource. The AP sends the time synchronization information to the STA through the first frequency domain resource, and the AP and the STA communicate in the first superframe through the second frequency domain resource in the dynamic scheduling manner.