Contention-Based PUSCH Uplink Transmission for Low Latency
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Solution Overview
Problem
In wireless communication systems, particularly in LTE, the existing method for transmitting uplink data introduces latency due to the need for UE to request resource allocation from a BS, which can degrade the quality of service for low-latency applications.
Innovation Solution
A method where UE can directly transmit uplink data through a contention-based PUSCH zone without an UL grant, using control information to determine the type of procedure, allowing selective operation between UL grant-based and contention-based data transmission to minimize latency and utilize all cell resources efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If UE requests resource allocation from BS before transmitting uplink data, then resource allocation is optimized and resource usage is maximized, but transmission latency increases
Solution Approach 1:
The uplink transmission resources are segmented into two distinct types: contention-based PUSCH resources for low-latency transmissions and scheduled PUSCH resources for optimized resource allocation. This segmentation allows different transmission scenarios to use appropriate resource types, resolving the contradiction between latency and resource efficiency.
Solution Approach 2:
The system dynamically selects between contention-based and scheduled PUSCH transmission modes based on service requirements and network conditions. The BS configures both types of resources and the UE adaptively chooses the appropriate mode, enabling the system to balance latency and resource efficiency dynamically rather than using a fixed approach.
2Loss of time
If UE directly transmits uplink data through contention-based PUSCH zone without UL grant, then transmission latency is reduced, but resource collision risk increases
Solution Approach 1:
The contention-based PUSCH transmission introduces an intermediary contention resolution mechanism where multiple UEs may attempt transmission simultaneously, and the BS mediates by receiving these transmissions and resolving collisions through appropriate feedback and retransmission coordination, thus enabling low-latency transmission while managing collision risks.
Solution Approach 2:
The system changes the transmission parameters by allowing UEs to directly access contention-based PUSCH resources without prior scheduling grants. This parameter change from grant-based to contention-based access reduces latency while the BS manages collision risks through configured resource parameters and contention resolution procedures.
3Quantity of substance
If BS schedules resource allocation for all UE transmissions, then resource utilization is optimized, but procedure complexity increases
Solution Approach 1:
The resource allocation procedure is segmented into two paths: contention-based PUSCH transmission for low-latency services that bypasses complex scheduling procedures, and scheduled PUSCH transmission for services requiring optimized resource allocation. This segmentation reduces overall procedure complexity by providing a simpler alternative path while maintaining resource optimization where needed.
Solution Approach 2:
The BS maintains the capability to configure both contention-based and scheduled PUSCH resources, making it universally adaptable to different service requirements. The system can serve both latency-sensitive and resource-efficient transmissions through a unified configuration approach, reducing the need for separate complex procedures.
Data Source
AI summary
The present specification provides a method for transmitting uplink data (UL data) requiring a low latency in a wireless communication system. The method performed by a terminal comprises: receiving control information related to a contention-based PUSCH zone from a base station; and transmitting uplink data to the base station on the basis of the received control information. The contention-based PUSCH zone is a resource area where uplink data of the terminal can be transmitted without allocation of a UL grant from the base station. Further, in order to distinguish between kinds of specific procedures performed by the terminal, the control information includes procedure-distinguishing information allocated for each kind of the specific procedures.