Random Access Code Sequence Grouping for RACH Control Reporting
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Solution Overview
Problem
Efficient reporting of control information in the Random Access Channel (RACH) for radio communication mobile stations is a challenge due to high cross-correlation between code sequences, which affects demultiplexing and detection at the base station, especially when multiple mobile stations transmit identical control information simultaneously.
Innovation Solution
A mobile station configuration that selects one code sequence from a base code sequence and its derived sequences, using CAZAC or GCL sequences, to efficiently transmit control information in the RACH, reducing cross-correlation and improving demultiplexing by associating control information with unique code sequences, thereby enabling efficient reporting without additional control information transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If code sequences are used to transmit control information in RACH, then control information can be reported efficiently, but cross-correlation between code sequences increases making demultiplexing and detection difficult
Solution Approach 1:
The code sequences are segmented into multiple groups where each group corresponds to specific control information types. This segmentation allows the base station to efficiently demultiplex and detect control information by identifying which group the received code sequence belongs to, thereby resolving the cross-correlation issue while maintaining reporting efficiency.
Solution Approach 2:
Different local qualities (distinct code sequences) are assigned to different control information types within each group. This ensures that while maintaining efficient reporting through group identification, the system also achieves accurate demultiplexing and detection by utilizing the unique local characteristics of each code sequence within its group.
2Productivity
If multiple mobile stations transmit identical control information simultaneously, then resource utilization improves, but cross-correlation between transmissions increases affecting detection
Solution Approach 1:
Multiple mobile stations transmitting identical control information are merged into the same code sequence group. This combining approach improves resource utilization by allowing simultaneous transmissions while maintaining detection reliability through the group-based identification mechanism that can handle multiple identical signals within each group.
3Measurement precision
If code sequences with low cross-correlation are used, then demultiplexing performance improves, but the number of available code sequences decreases
Solution Approach 1:
Each code sequence group serves multiple functions: it identifies the control information type while also providing unique sequences for demultiplexing. This multi-functionality allows the system to maintain good demultiplexing performance with fewer total sequences by making each sequence serve both identification and differentiation purposes across different groups.
Data Source
AI summary
A radio performs random access by receiving control information and grouping a predetermined number of sequences that are generated from a plurality of base sequences into a plurality of groups by partitioning the predetermined number of sequences. At least one of the groups is associated with a first respective range of data amounts and a first respective range of reception qualities. Sequences generated from a common base sequence are arranged in an increasing order of respective cyclic shifts associated with the sequences. A sequence is randomly selected from a plurality of sequences contained in one group of the plurality of groups. A position at which the predetermined number of sequences are partitioned is determined based on the control information. A number of sequences contained in each of the plurality of groups varies in accordance with the control information.