Uplink Mini-Slot Transmission Scheduling
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Solution Overview
Problem
Current wireless communication systems face high signaling overhead and inefficiencies in uplink transmission using mini-slots, particularly in unlicensed access scenarios, where devices need to perform clear channel assessments before transmitting, leading to increased latency and reduced channel access granularity.
Innovation Solution
Implementing multi-mini slot scheduling and dynamic mini-slot configurations that allow wireless devices to transmit within the earliest available mini-slot after clear channel assessment, using reduced demodulation reference signal density and shared HARQ processes to minimize overhead and maximize channel access granularity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mini-slots are used to reduce transmission latency and improve channel access granularity, then channel access efficiency is improved, but signaling overhead increases due to control information in every mini-slot
Solution Approach 1:
The patent segments the control information transmission by separating it from data transmission. Control information is transmitted only in the first mini-slot of a burst, while subsequent mini-slots carry only data. This segmentation reduces the frequency of control signaling while maintaining the fine-grained channel access capability of mini-slots, thereby resolving the contradiction between improved channel access efficiency and increased signaling overhead.
2Reliability
If clear channel assessment is performed before every transmission, then channel access reliability is improved, but transmission latency increases due to assessment time
Solution Approach 1:
The patent applies preliminary action by performing the clear channel assessment once at the beginning of the transmission burst before any data transmission. The assessment result is then valid for the entire burst of mini-slots, eliminating the need to repeat the assessment for each mini-slot. This approach maintains channel access reliability while significantly reducing the time loss associated with repeated assessments.
3Adaptability or versatility
If control information is included in every mini-slot, then scheduling flexibility is improved, but device complexity increases due to monitoring requirements
Solution Approach 1:
The patent segments control information transmission to occur only in the first mini-slot of a burst, rather than in every mini-slot. This reduces the monitoring burden on the wireless device from checking every mini-slot to checking only the first mini-slot of each burst, thereby reducing device complexity while maintaining scheduling flexibility through the initial control information that covers the entire burst.
4Loss of information
If full slot transmissions are used, then signaling overhead is reduced, but channel access granularity is coarse and latency increases
Solution Approach 1:
The patent introduces dynamic mini-slot configurations that allow the system to adaptively choose between full slot transmissions and mini-slot transmissions based on traffic conditions and channel availability. This dynamic approach enables fine-grained channel access when needed (reducing latency) while allowing full slot transmissions when appropriate (reducing signaling overhead), thus resolving the contradiction between these two parameters.
Data Source
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AI summary
A method in a wireless device for performing an uplink transmission to a base station in a wireless access system, wherein the wireless access system comprises one or more mini-slot configurations, the method comprising performing a clear channel assessment for identifying a transmission opportunity and determining the start of a mini-slots. The wireless device performing an uplink transmission within the determined mini-slot wherein the transmission is performed according to a predetermined configuration for mini-slot communication between the base station and the wireless device, such that the base station can identify the start of the uplink transmission.