UE Capability Signaling in Initial RACH Under MSG3 Bit Limits
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Solution Overview
Problem
Existing 3GPP standards face challenges in enabling the network to be aware of UE capabilities before the completion of the RACH procedure, particularly due to space limitations in MSG3 messages, which are crucial for configuring subsequent messages.
Innovation Solution
A method where a base station configures UEs to send early UE capability indications during the RACH procedure by utilizing reserved bits in the MAC header or RRC Connection Request messages, ensuring compatibility with network encoding and bit allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE sends capability information after RACH procedure completion using UE capability transfer procedure, then the network can obtain complete UE capabilities, but the network cannot be aware of UE capabilities before completion of the RACH procedure which delays network configuration
Solution Approach 1:
The patent applies preliminary action by having the UE send capability information in MSG3 during the RACH procedure before completion, rather than waiting for the standard post-RACH capability transfer. This allows the network to obtain UE capabilities earlier and configure subsequent messages accordingly, resolving the time delay while maintaining reliability through the configured bit field format.
2Loss of time
If the UE includes capability information in MSG3 message, then the network can obtain capabilities earlier, but the message space is limited which restricts the amount of capability information that can be transmitted
Solution Approach 1:
The patent applies local quality by allocating specific bit fields within the MSG3 message structure for capability indication. Instead of using the entire message space, dedicated bits are assigned for capability information, allowing early capability transmission while preserving other message functions and maintaining compatibility with existing MSG3 formatting requirements.
Solution Approach 2:
The patent applies parameter changes by configuring the UE to transmit capability information using specific bit field formats and encodings in MSG3. The network configures the exact parameter structure (number of bits, encoding scheme, mapping relationships) to optimize capability transmission within the constrained message space while enabling early capability indication.
3Quantity of substance
If reserved bits in MAC header or RRC Connection Request messages are used for capability indication, then message space efficiency is maintained, but the configuration complexity increases
Solution Approach 1:
The patent applies preliminary action by having the network send configuration information to the UE before the RACH procedure, specifying which reserved bits to use and how to encode capability information. This pre-configuration simplifies the UE's task during MSG3 transmission, reducing in-message complexity while maintaining efficient message space utilization through predetermined bit allocations.
Data Source
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AI summary
An approach is provided to set up a User Equipment (UE) for an initial Random Access Channel (RACH) procedure to a cellular network. A configuration of a base station of the cellular network for receiving early indication of UE capabilities as a part of the RACH procedure is communicated from the base station, for reception by at least one UE prior to starting the RACH procedure.