RACH Spreading Code Configuration for Orthogonal UE Access
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently managing random access channel (RACH) procedures, particularly in determining appropriate spreading codes for RACH occasions, which affects network performance and differentiation between user equipment (UE) transmissions.
Innovation Solution
The method involves transmitting random access configuration indicating spreading code information from a base station to user equipment (UE), allowing the UE to determine and apply specific spreading codes based on the RACH occasion, quantity of repetitions of the preamble, and RACH capability, enabling efficient RACH procedure execution and orthogonality in UE transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spreading codes are used for RACH occasions, then orthogonality between UE transmissions is improved, but device complexity increases due to code determination and application requirements
Solution Approach 1:
The patent applies parameter changes by dynamically selecting spreading codes based on RACH occasion indices and repetition quantities. The base station configures multiple spreading codes with different parameters (orthogonal codes, cyclic shifts) and the UE selects appropriate codes based on predefined rules tied to RACH occasion parameters, thereby achieving orthogonality through parameter variation rather than complex deterministic algorithms
Solution Approach 2:
The base station performs preliminary action by pre-configuring spreading code information for multiple RACH occasions before the actual RACH procedure. The network provides spreading code indices and associated parameters in advance through system information or RRC signaling, allowing UEs to prepare and select appropriate codes without real-time computation, thus reducing device complexity while maintaining orthogonality
2Productivity
If spreading code information is configured for multiple RACH occasions, then network performance is improved through better differentiation, but message complexity increases due to additional configuration parameters
Solution Approach 1:
The patent applies universality by designing a multi-functional spreading code configuration mechanism that serves multiple purposes: differentiating between RACH occasions, supporting repetition scenarios, maintaining orthogonality, and enabling backward compatibility. The same spreading code configuration framework handles both single-occasion and multi-occasion scenarios, as well as cases with and without repetitions, thereby improving network performance without proportionally increasing message complexity
Solution Approach 2:
The patent segments the spreading code configuration into hierarchical levels: common spreading code parameters applicable to all RACH occasions, and occasion-specific spreading code indices. This segmentation allows the network to configure multiple RACH occasions with differentiated spreading codes while reusing common parameter sets, thus achieving better differentiation without linearly increasing configuration overhead
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may receive, from a base station, a random access configuration indicating spreading code information for a set of random access channel (RACH) occasions associated with a RACH procedure, and transmit, to the base station, a physical RACH communication in a RACH occasion, of the set of RACH occasions, using a spreading code, wherein the spreading code is determined based at least in part on the spreading code information. Numerous other aspects are provided.