Fast Session Transfer Multiband Wireless Switching
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Solution Overview
Problem
Current wireless communication standards, such as IEEE 802.11, lack efficient methods for switching wireless devices and access points between different frequency bands, particularly in scenarios involving tunneled direct link setups, leading to inefficiencies in session transfers and security key management.
Innovation Solution
Incorporating enhanced distributed channel access (EDCA) and very-high throughput (VHT) operation elements into Fast Session Transfer (FST) messages, adding multiband capabilities to Probe Requests and TDLS discovery frames, and creating a pairwise transient key for new frequency bands to enable seamless transitions without recalculating security keys, along with encapsulating FST Setup frames in data frames for management frame forwarding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wireless devices switch between frequency bands using conventional methods, then band switching is possible, but session transfer efficiency is poor and key recalculation overhead increases
Solution Approach 1:
The patent performs preliminary actions by establishing a pairwise transient key (PTK) for the new frequency band before the actual band switch occurs. During the FST setup phase in the current band, the PTK for the target band is calculated and stored in advance. When the band switch happens, this pre-calculated PTK is immediately activated without requiring recalculation, thus resolving the contradiction between session transfer efficiency and key recalculation time.
2Adaptability or versatility
If multiband capability is added to devices, then frequency band flexibility improves, but device complexity increases
Solution Approach 1:
The patent implements multiband capability by enabling wireless devices to operate across multiple frequency bands (2.4 GHz, 5 GHz, 60 GHz) using a unified FST mechanism. The same FST message structures, key management procedures, and session transfer protocols are applied universally across all band combinations, allowing devices to flexibly switch between bands without requiring separate complex mechanisms for each band pair, thus achieving versatility without proportional complexity increase.
3Ease of operation
If FST Setup frames are encapsulated in data frames, then management frame forwarding capability improves, but frame processing complexity increases
Solution Approach 1:
The patent applies nesting by encapsulating FST Setup frames (management frames) within data frames. The FST Setup Request and Setup Response frames are placed as payloads inside data frame structures that can be forwarded by APs. This nested structure allows management frame functionality to be carried through the data plane infrastructure, enabling AP forwarding capability while reusing existing data frame processing paths.
Data Source
AI summary
Embodiments are directed to switching of stations STA, access points APs and PCPs that are communicating through a wireless link from one frequency band to another. One embodiment is directed to switching of stations STA that are communicating through a tunneled direct link setup (TDLS) link from one frequency band to another. A multiband element may be added to a TDLS discovery request and TDLS discovery response frames to allow each of the stations communications through a TDLS to determine if the other station has multiband capability. In one embodiment, a pairwise transient key (PTK) is created for both a current band in which the stations STA are communicating and a new band over which the stations may communicate in the future. In this way there is no need to calculate a new pairwise transient key PTK for the new frequency band.