Uplink Carrier Selection for NR Random Access
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the New Radio (NR) system, high-frequency cells exhibit asymmetric uplink and downlink coverage due to limited terminal device transmit power, necessitating the use of supplementary uplink (SUL) carriers to expand uplink coverage, but existing methods are inadequate for carrier selection and resource configuration during handovers.
Innovation Solution
A method for selecting and configuring uplink carriers in a cell supporting multiple frequency bands, including indication information for resource configuration, such as dedicated random access resources and power control settings, to ensure consistent uplink and downlink coverage during handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If supplementary uplink (SUL) carriers are introduced to expand uplink coverage in high-frequency cells, then uplink coverage consistency with downlink coverage is improved, but the complexity of carrier selection and resource configuration during handovers increases
Solution Approach 1:
The network device pre-configures multiple uplink carriers (including SUL carriers) and their associated resource information before handover occurs. The terminal device receives and stores this configuration information in advance, including uplink carrier frequencies, bandwidths, and random access resources. During handover, the terminal can quickly select from pre-configured carriers based on simple criteria rather than performing complex real-time analysis, thus resolving the contradiction between coverage consistency and selection complexity
Solution Approach 2:
The patent implements a feedback mechanism where the terminal device measures signal quality (e.g., RSRP) of downlink carriers and reports this information to the network device. The network device uses this feedback to determine which uplink carrier is most suitable for the terminal and provides explicit selection guidance. This feedback loop enables intelligent carrier selection that maintains coverage consistency while simplifying the terminal's decision-making process
2Reliability
If multiple uplink frequency bands are deployed in a cell, then uplink coverage is expanded to match downlink coverage, but the difficulty of determining appropriate random access resources increases
Solution Approach 1:
The patent segments the random access resources by associating them with specific uplink carriers. Each uplink carrier (normal uplink and SUL carriers) has its own dedicated random access resources configured by the network. The terminal device determines which random access resources to use based on which uplink carrier it selects, effectively dividing the resource selection problem into manageable carrier-specific segments rather than requiring selection from a single pooled resource set
Solution Approach 2:
The patent introduces an intermediary mechanism where the network device acts as a mediator to guide random access resource selection. The network device configures indication information that links specific random access resources to specific uplink carriers and transmits this configuration to the terminal. This intermediary configuration layer simplifies the terminal's task by providing clear mappings rather than requiring the terminal to independently analyze and determine the most appropriate resources among multiple options
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
This application provides a communication method, a terminal device, and a network device, so that an uplink carrier can be selected from a cell supporting a plurality of uplink frequency bands, for performing random access. The communication method includes: receiving, by a terminal device, indication information sent by a network device, where the indication information is used to indicate resource configuration information of at least one uplink carrier, the at least one uplink carrier includes a first uplink carrier and/or at least one second uplink carrier, the first uplink carrier and the at least one second uplink carrier are different uplink carriers in a cell of the network device, and the first uplink carrier and the at least one second uplink carrier are corresponding to one downlink carrier in the cell; and determining, by the terminal device based on the resource configuration information of the at least one uplink carrier, one uplink carrier from the at least one uplink carrier as a target carrier for performing random access.