Grant-Free Uplink Transmission on Contention-Based Bandwidth Part
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Solution Overview
Problem
In 5G New Radio (NR) networks, user devices (UEs) face delays and bandwidth consumption during contention-based uplink transmissions due to the need for random access procedures, which can result in missed opportunities for data transmission when another device gains access to the same time resource, especially for devices with small amounts of data to transmit.
Innovation Solution
User devices can transmit small amounts of data on a contention-based bandwidth part (BWP) without first acquiring an uplink grant by determining time alignment with the base station and performing a listen-before-talk (LBT) procedure to assess availability of a time resource, allowing for grant-free transmissions within the idle state of the protocol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a UE performs random access procedure to obtain uplink grant before transmitting data, then the transmission can be scheduled and controlled, but the transmission delay increases and bandwidth is consumed by the access procedure
Solution Approach 1:
The patent extracts the random access procedure from the mandatory transmission path for small data packets. UEs with small data transmissions can skip the RACH procedure and directly transmit on contention-based BWP resources, while large data transmissions still require the full grant-based procedure. This separation allows small data to bypass the time-consuming access procedure.
Solution Approach 2:
The patent segments the uplink transmission resources into dedicated BWP resources for small data packets and general resources for large data transmissions. By dividing the BWP into specific time-frequency resources allocated for contention-based access, the system enables direct transmission without full grant acquisition for small packets while maintaining controlled access for larger transmissions.
2Reliability
If a UE performs random access procedure to obtain uplink grant, then the base station can allocate time resources, but the bandwidth consumption increases and power is consumed during the procedure
Solution Approach 1:
The patent removes the random access procedure from the transmission path for small data packets by allocating dedicated contention-based BWP resources. UEs can directly transmit on these pre-configured resources without performing RACH, thereby eliminating the additional power consumption associated with preamble transmission, random access response processing, and grant acquisition.
Solution Approach 2:
The base station performs preliminary resource allocation by configuring dedicated BWP resources for contention-based access before the UE needs to transmit. This advance allocation of time-frequency resources and transmission parameters eliminates the need for real-time grant acquisition, reducing both bandwidth consumption and power expenditure during the actual data transmission phase.
3Loss of time
If a UE transmits on contention-based BWP without uplink grant, then the transmission delay is reduced, but the risk of collision with other devices increases
Solution Approach 1:
The base station performs preliminary configuration of contention-based BWP resources, allocating specific time-frequency resources and transmission parameters to UEs before they need to transmit. This advance setup includes providing BWP IDs, frequency offsets, and other parameters that enable UEs to directly access resources without grant acquisition, reducing delay while maintaining collision avoidance through structured resource allocation.
Solution Approach 2:
The patent implements dynamic resource allocation where the base station can adjust BWP configurations, time slot allocations, and resource availability based on current network conditions and contention levels. This dynamic adjustment allows the system to optimize between collision avoidance and transmission efficiency by adapting resource allocation patterns to actual traffic conditions.
Data Source
AI summary
A method in a UE for transmitting data via a contention-based BWP in an idle state of a protocol for controlling radio resources can be executed by one or more processors. The method includes determining that the UE has time alignment with a base station for an uplink transmission to the base station (602), determining that a time resource for the uplink transmission is available on the contention-based BWP (604), and transmitting data within the time resource in accordance with the time alignment, while the UE is in the idle state (606).