Random Access Response Segmentation for RedCap Bandwidth Limitations
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current communication networks lack a means to identify whether a user equipment (UE) is a RedCap UE and determine its bandwidth limitations, leading to issues such as R18 Redcap UEs receiving PDCCH scheduling that exceeds their supported bandwidth, resulting in failed decoding of RAR PDSCH.
Innovation Solution
The network node transmits a message with an indication during the random access procedure, allowing RedCap UEs to interpret PDCCH differently, accommodating their bandwidth limitations by providing multiple RARs, where one RAR does not and another does, ensuring the second RAR is within the UE's supported bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the network node transmits a single random access response (RAR) without bandwidth indication, then the transmission procedure is simple and fast, but RedCap UEs cannot decode the PDSCH when it exceeds their supported bandwidth
Solution Approach 1:
The patent segments the RAR transmission by dividing it into multiple parts: a first RAR message and a second RAR message. The first RAR contains bandwidth information indicating whether the scheduled PDSCH accommodates the UE's bandwidth limitation, while the second RAR contains the actual random access response. This segmentation allows UEs to first check the bandwidth indication and selectively decode only the relevant second RAR, ensuring reliable decoding for both RedCap and non-RedCap UEs.
Solution Approach 2:
The patent applies preliminary action by including bandwidth limitation indication information in the first RAR message before transmitting the second RAR. This allows UEs to预先 determine whether they should decode the upcoming PDSCH containing the second RAR, preventing wasted decoding attempts and ensuring that the RAR is received reliably by the intended UE type.
2Reliability
If dedicated RACH partitions are created for RedCap UEs, then bandwidth limitation identification is achieved, but additional network resources and system complexity are required
Solution Approach 1:
The patent makes the random access procedure universal by designing a single RAR transmission structure that serves both RedCap UEs and non-RedCap UEs. The first RAR message includes a bandwidth indication field that works for all UE types, eliminating the need for separate dedicated RACH partitions. This multi-functional approach allows the same physical resources to be efficiently used for identifying and serving different UE categories.
Solution Approach 2:
The patent enables UEs to self-identify and self-select the appropriate RAR based on the bandwidth limitation indication in the first RAR message. RedCap UEs autonomously determine whether to decode the second RAR by checking the bandwidth indication, without requiring the network to explicitly assign dedicated resources. This self-service mechanism reduces network overhead and resource consumption.
3Adaptability or versatility
If multiple random access responses are transmitted with bandwidth indication, then RedCap UEs can successfully decode within their bandwidth limits, but the message transmission becomes more complex
Solution Approach 1:
The patent segments the RAR transmission into two distinct messages: the first RAR containing bandwidth limitation indication, and the second RAR containing the actual random access response. This segmentation provides adaptability by allowing the network to flexibly accommodate different UE bandwidth capabilities while maintaining a relatively simple overall structure that builds upon the existing two-step random access framework.
Data Source
AI summary
An apparatus includes: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to: transmit, to a network node, a random access preamble during a random access procedure; and receive, from the network node, a message including an indication, wherein the indication indicates one of: one random access response that accommodates a bandwidth limitation of the terminal device, wherein the bandwidth limitation of the terminal device is within a wider system bandwidth, or multiple random access responses comprising a first random access response that does not accommodate the bandwidth limitation of the terminal device, and a second random access response that accommodates the bandwidth limitation of the terminal device.