Peer Power Save Mode in TDLS Wireless Networks
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Solution Overview
Problem
In WLAN environments using IEEE 802.11a/b/g, non-AP STAs cannot enjoy DLS services due to legacy APs not supporting QoS, and existing wireless communication protocols cannot apply data buffering and communication procedures for STAs in power save mode within TDLS wireless networks.
Innovation Solution
The introduction of Peer Power Save Mode (PPSM) allows non-AP STAs to operate in power save mode within TDLS wireless networks by defining PPSM client and AP modes, enabling data buffering and transmission through the TDLS link without changing the data receiving path from the AP, using power management information and new TDLS frames like the peer traffic indication frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If legacy APs are used in WLAN environments (IEEE 802.11a/b/g), then compatibility and ease of operation are maintained, but QoS support and DLS services are not available
Solution Approach 1:
The patent introduces a tunnel mechanism where data frames are encapsulated and transmitted through the legacy AP as if they were standard data frames. The AP relays these tunneled frames between STAs without needing to understand or process QoS protocols, effectively mediating between the direct link requirement and the legacy infrastructure.
Solution Approach 2:
The patent embeds TDLS-specific control frames and data frames within standard IEEE 802.11 data frame structures. The tunneled direct link setup frames are nested inside regular data frames that can be processed by legacy APs, allowing multiple layers of protocol functionality to coexist.
2Use of energy by moving object
If STAs operate in power save mode to reduce energy consumption, then power efficiency improves, but data transmission and reception capability deteriorates
Solution Approach 1:
The patent implements a buffer mechanism where the peer STA pre-stores data frames intended for the power-saving STA before the latter enters sleep mode. This preliminary action ensures data is ready for immediate transmission upon the STA's wake-up, eliminating transmission delays and maintaining reliability.
Solution Approach 2:
The patent employs a buffer status notification mechanism where the power-saving STA periodically checks with its peer about buffered data. This feedback loop allows the sleeping STA to wake up only when necessary to retrieve data, optimizing power consumption while ensuring data is transmitted promptly.
3Productivity
If direct link setup is implemented between non-AP STAs to improve communication efficiency, then productivity improves, but compatibility with legacy APs deteriorates
Solution Approach 1:
The legacy AP serves as an unwitting intermediary that simply relays tunneled frames between STAs without needing to understand the direct link protocol. The AP treats tunneled frames as ordinary data frames, maintaining full compatibility while enabling direct communication functionality.
Solution Approach 2:
The patent designs the tunnel mechanism to use universal IEEE 802.11 data frame structures that can be processed by any legacy AP. The same frame format serves both as standard data traffic and as encapsulated TDLS control traffic, making the solution universally compatible.
Data Source
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AI summary
A protocol for a peer power save mode (PPSM) in a tunneled direct link setup (TDLS) wireless network and a system therefor are provided. A station (STA) set up a TDLS link can send a frame having a power management bit set to a peer STA to enter into a power save mode (PSM). In this case, the station entering into the PSM operates in a PPSM client mode. When the peer STA operates in the PPSM client mode, the STA can operate in the PPSM access point (AP) mode or can enter into the PPSM client mode. The STA operating in the PPSM AP mode buffers data for the STA operating in the PPSM client mode and informs the peer STA of information indicating that there is buffered data by the use of a peer traffic indication frame or the like. In principle, a U-APSD procedure can be applied to the transmission of data through a direct link from the STA operating in the PPSM AP mode to the STA operating in the PPSM client mode.