WLAN Direct Link Relay for Power Management
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Solution Overview
Problem
In Wireless Local Area Networks (WLAN) systems, especially those supporting Machine to Machine (M2M) communication, there is a need for efficient power management to extend the battery life of mobile devices, as they often operate in environments with multiple stations and require increased mobility, leading to higher power consumption.
Innovation Solution
A communication method that sets up a direct link between chargeable and unchargeable stations, allowing the unchargeable station to relay data frames with reduced transmit power, thereby minimizing power consumption and extending battery life by operating in a doze state during non-communication intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an STA transmits data frames directly to the AP with high transmit power to ensure reliable communication, then the communication reliability is improved, but the power consumption increases and battery life decreases
Solution Approach 1:
The patent introduces a relay STA as an intermediary node between the unchargeable STA and the AP. The unchargeable STA transmits data frames to the relay STA with lower power, and the relay STA forwards them to the AP. This mediator approach allows the unchargeable STA to achieve reliable communication without consuming high power directly.
Solution Approach 2:
The communication path is segmented into two hops: unchargeable STA → relay STA → AP. Instead of a single direct transmission, the data frame transmission is divided into multiple segments, each using lower power levels, thereby reducing the overall power consumption of the unchargeable STA while maintaining communication reliability.
2Speed
If an unchargeable STA operates continuously in an awake state to handle communications, then the communication responsiveness is improved, but the battery life decreases
Solution Approach 1:
The unchargeable STA operates in periodic cycles, alternating between awake and doze states. During awake periods, it handles communications; during doze periods, it conserves power. The relay STA and AP coordinate to ensure data frames are transmitted during awake periods, maintaining responsiveness while extending battery life through periodic operation.
Solution Approach 2:
The relay STA acts as a buffer and mediator, holding data frames when the unchargeable STA is in doze state and delivering them when the STA wakes up. This allows the unchargeable STA to remain in doze state longer without compromising communication responsiveness, as the intermediary manages the timing of data transfers.
3Productivity
If a direct link is set up between unchargeable STA and AP for efficient data transmission, then the data rate is improved, but the power consumption increases
Solution Approach 1:
The direct link transmission is segmented into two separate transmission links: unchargeable STA to relay STA, and relay STA to AP. Each link operates at lower data rates and lower power levels compared to a single high-rate direct link, achieving the trade-off between productivity and energy consumption by distributing the data transmission load across multiple lower-power segments.
Data Source
AI summary
A communication method performed by a station (STA) in a Wireless Local Area Network (WLAN) system is provided. The method includes: broadcasting a Direct Link Setup (DLS) discovery request frame for discovering a destination STA with which a direct link will be set up; receiving a DLS discovery response frame from the destination STA in response to the DLS discovery request frame; setting up the direct link with the destination STA; and transmitting a data frame to an Access Point (AP). The step of transmitting the data frame comprises transmitting the data frame to the destination STA through the direct link. The data frame received by the destination STA is relayed to the AP.