Floating Frame Channel Occupancy Time In Fixed Frame Period
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Solution Overview
Problem
European Telecommunications Standards Institute (ETSI)-compliant frame-based equipment (FBE) cannot coexist on the same shared unlicensed spectrum frequency band, leading to dominance by one device with a lower fixed frame period, resulting in transmission collisions without a prioritization mechanism.
Innovation Solution
Implementing a method where a processor in a FBE performs clear channel assessment (CCA) and transmits during a channel occupancy time (COT) within a fixed frame period (FFP) after determining a selected number of observation slots, allowing the COT to 'float' and enabling fair sharing of the unlicensed spectrum by inserting a random phase in the FFP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple ETSI-compliant FBE devices operate on the same shared unlicensed spectrum frequency band with the same fixed frame period, then each device attempts to transmit according to its fixed frame period, but one device completely dominates or transmissions completely collide without a prioritization mechanism
Solution Approach 1:
The patent introduces a dynamic element to the otherwise static fixed frame period by allowing the channel occupancy time (COT) to float within the FFP. This is achieved by inserting a random phase offset in the range of [0, FFP) before each COT, making the transmission timing dynamic rather than fixed, which enables multiple FBE devices to coexist without complete dominance or collision by varying their actual transmission start times within their respective frame periods
2Ease of operation
If a fixed frame period is used for transmission, then transmission timing is predictable and simple, but multiple devices cannot share the channel fairly and collisions occur
Solution Approach 1:
The patent introduces asymmetry by combining a fixed structural framework (FFP) with a random variable element (phase offset). Each device maintains its fixed frame period structure for predictability, but the random phase offset creates asymmetric timing offsets between different devices, allowing them to stagger their transmissions and share the channel fairly without requiring complex coordination mechanisms
3Reliability
If clear channel assessment is performed before transmission, then channel access is safer and collisions are reduced, but additional observation slots are required increasing time delay
Solution Approach 1:
The patent performs clear channel assessment (CCA) in advance during the random phase offset period before the actual channel occupancy time begins. By conducting CCA during these preliminary observation slots inserted at the beginning of each floating COT, the system ensures safe channel access is established before data transmission starts, reducing the risk of collisions while the random timing already provides some inherent collision avoidance
Data Source
AI summary
Examples pertaining to a floating frame-based channel occupancy time (COT) in a fixed frame period (FFP) in mobile communications are described. An apparatus implemented in FBE performs clear channel assessment (CCA) of a channel. The apparatus then transmits during a COT within a FFP in response to the CCA indicating the channel to be clear for transmission.