AP-orchestrated overlaid transmissions for low-latency wireless
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Solution Overview
Problem
Current wireless communication systems, particularly in unlicensed bands, face challenges in supporting low-latency and high-reliability data traffic due to inefficient channel access mechanisms, leading to high collision probabilities and poor channel usage.
Innovation Solution
The method involves an Access Point (AP) reserving a TXOP on a wireless channel and determining transmit parameters for associated stations. The AP sends a message triggering scheduled transmissions and allows additional stations to perform overlaid transmissions with specific parameters, enabling efficient use of radio resources and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If distributed channel access (DCF) is used, then devices can access the channel independently, but channel collision probability increases and channel usage efficiency deteriorates under high load
Solution Approach 1:
The AP acts as an intermediary that coordinates channel access for multiple STAs. Instead of allowing direct distributed access between STAs (which causes collisions), the AP mediates by scheduling uplink transmissions, allocating RUs, and controlling the TXOP structure, thereby eliminating collisions while maintaining efficient channel usage.
Solution Approach 2:
The patent inverts the traditional distributed access model by implementing centralized scheduling at the AP. Rather than STAs independently accessing the channel (bottom-up approach), the AP controls and schedules all uplink transmissions (top-down approach), fundamentally changing the access paradigm to eliminate collisions.
2Reliability
If centralized channel access with AP control is implemented, then channel collision probability decreases, but channel access delay increases due to scheduling overhead
Solution Approach 1:
The AP performs preliminary actions by pre-allocation of RUs and pre-scheduling of uplink transmissions within the TXOP structure. By preparing the channel allocation in advance and notifying STAs of their scheduled resources, the system eliminates waiting time and scheduling delays during actual transmission.
Solution Approach 2:
The patent implements continuous useful action by utilizing the entire TXOP duration for productive transmissions. The structured allocation ensures that the channel remains continuously utilized without idle periods or re-scheduling overhead, maintaining high efficiency while providing deterministic access.
3Device complexity
If traditional OFDMA with single RU allocation per STA is used, then resource allocation is simple, but flexibility in supporting diverse traffic requirements (especially low-latency traffic) is limited
Solution Approach 1:
The patent segments the channel access into two distinct types: scheduled transmissions for regular traffic and random access transmissions for low-latency traffic. This segmentation allows each transmission type to have optimized resource allocation rules, with scheduled traffic using traditional RU allocation and random access traffic using contention-based access without requiring RU assignment.
Solution Approach 2:
The system dynamically adapts resource allocation based on traffic requirements. For latency-sensitive traffic, the AP allows random access transmissions that can immediately utilize available resources without waiting for scheduling. This dynamic behavior enables the system to flexibly respond to diverse traffic patterns while maintaining overall resource efficiency.
Data Source
Figure 1
Figure 2~3A
Figure 3B
AI summary
An access point (10) of a wireless communication system reserves a transmit opportunity, TXOP, on a wireless channel. Further, the access point (10) determines, for a wireless station (11) associated with the access point (10), a first set of one or more transmit parameters to be applied in a first wireless transmission from the wireless station (11) to the access point (10). Further, the access point (10) sends a message (405) for triggering the first wireless transmission by the wireless station (11). The message (405) indicates the first set of one or more transmit parameters. Further, the message (405) indicates a second set of one or more transmit parameters and that at least one additional wireless station (11) receiving the message (405) is allowed to perform a second wireless transmission in the TXOP for a duration smaller than the first wireless transmission and using the indicated second set of one or more transmit parameters and radio resources which are at least in part overlapping with radio resources allocated to the first wireless transmission.