Uplink BWP Management via RAR UL Grant Truncation
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing bandwidth parts (BWPs) for efficient communication in fifth-generation cellular systems, particularly in scenarios requiring high-speed, high-capacity, low-latency, and reliable connections.
Innovation Solution
A terminal and base station apparatus are designed to dynamically manage initial and additional UL BWPs through RRC messages, utilizing RAR UL grants for scheduling PUSCH, with truncation or bit insertion decisions based on initial BWP bandwidth, enabling efficient frequency resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If additional UL BWP is configured to support high-speed and high-capacity transmission, then the communication capacity and speed are improved, but the device complexity and resource management overhead increase
Solution Approach 1:
The patent implements dynamic BWP switching mechanisms where the terminal can switch between initial UL BWP and additional UL BWP based on communication requirements. The base station dynamically configures and activates additional UL BWP through RRC messages and DCI indicators, allowing the system to adapt bandwidth resources in real-time according to traffic demands, thereby achieving high-speed and high-capacity transmission while maintaining manageable complexity through structured control procedures
Solution Approach 2:
The patent segments the uplink bandwidth into multiple parts: an initial UL BWP for basic communication and additional UL BWPs for enhanced capacity. This segmentation allows the system to allocate specific bandwidth portions for different purposes - the initial BWP handles control and basic data, while additional BWPs provide extra capacity when needed. The segmented structure simplifies management by dividing the complex bandwidth allocation problem into manageable parts with clear activation and deactivation procedures
2Loss of information
If the first field in RAR UL grant is truncated to indicate frequency resource allocation, then the message length is reduced, but the frequency resource allocation precision may be compromised
Solution Approach 1:
The patent applies local quality by making the truncation decision context-dependent on the initial UL BWP bandwidth. When the initial UL BWP bandwidth is small (≤100 RBs), the first field is truncated to 5 bits, which is sufficient for precise frequency allocation in smaller bandwidths. When the initial UL BWP bandwidth is large (>100 RBs), the first field is not truncated and retains its full 15 bits, ensuring adequate precision for frequency resource allocation across larger bandwidths. This localized adaptation of field length based on specific bandwidth conditions optimizes both message efficiency and allocation precision
Solution Approach 2:
The patent changes the parameter of the first field length in the RAR UL grant message based on the initial UL BWP bandwidth configuration. The system dynamically adjusts whether to truncate the first field from 15 bits to 5 bits depending on the bandwidth size. This parameter change allows the message structure to adapt to different bandwidth scenarios, maintaining appropriate frequency resource allocation precision while optimizing message length for each specific case
3Measurement precision
If bit is inserted into the first field of RAR UL grant, then the frequency resource allocation precision is improved, but the message processing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the terminal with the initial UL BWP bandwidth information through RRC messages before the random access procedure. This advance configuration allows the terminal to know in advance whether to insert a bit into the first field of the RAR UL grant message. The base station also prepares the appropriate RAR UL grant format based on the configured bandwidth. This preliminary setup eliminates the need for complex real-time decision-making during message processing, as both parties already know the required format based on pre-established bandwidth configurations
Solution Approach 2:
The patent implements feedback mechanisms where the base station monitors the initial UL BWP bandwidth configuration and provides appropriate RAR UL grant messages with the correct first field length. The terminal feedbacks its capability and configuration status, allowing the base station to adjust the RAR UL grant format accordingly. This feedback loop ensures that the message processing complexity is managed systematically, with the base station adapting the message format based on terminal feedback about the configured bandwidth, rather than requiring complex real-time processing at both ends
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A terminal apparatus that communicates with a base station apparatus includes: a reception unit configured to receive a configuration of an initial uplink (UL) bandwidth part (BWP) and a configuration of an additional UL BWP via a radio resource control (RRC) message and receive a random access response (RAR) message including an RAR UL grant; and a transmission unit configured to transmit a physical uplink shared channel (PUSCH) in an active UL BWP, wherein one of the initial UL BWP and the additional UL BWP is activated as the active UL BWP, the PUSCH is scheduled by using the RAR UL grant, a first field included in the RAR UL grant is used to indicate frequency resource allocation of the PUSCH, and whether the first field is to be truncated or whether a bit is to be inserted into the first field is determined based on a bandwidth of the initial UL BWP.