CRC Control Message Format with Implicit MAC_ID Masking
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Solution Overview
Problem
In mobile communication systems using Time Division Multiplexing (TDM) and Code Division Multiplexing (CDM), the existing error detection code generation methods waste resources and reduce transmission efficiency due to excessive power consumption in broadcasting Walsh Code Space Identification (WSI) information to all terminals, and lack effective error detection capabilities.
Innovation Solution
A modified control message format is introduced, incorporating an additional Walsh Code Allocation (WCA) field to reduce the number of bits and improve error detection, using a double CRC mechanism where the MAC_ID is implicitly masked, and error detection codes are generated using control information, Walsh space indication identifiers, and terminal identifiers to enhance resource utilization and error detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Walsh Code Space Identification (WSI) information is broadcast to all terminals using excessive power to ensure reception in worst environment, then all terminals can receive WSI information reliably, but power consumption increases significantly
Solution Approach 1:
The patent applies local quality by differentiating power allocation for WSI broadcasting based on terminal groups. Instead of uniform high-power broadcasting to all terminals, the system identifies terminals in worst environments and provides them with enhanced reception capability through dedicated high-power WSI messages, while terminals in better environments receive WSI at lower power levels.
Solution Approach 2:
The patent implements preliminary action by sending high-power WSI information in advance to terminals that may be in worst reception environments before actual data transmission begins. This allows these terminals to prepare their reception parameters ahead of time, ensuring they can reliably receive subsequent lower-power WSI broadcasts and data transmissions.
2Ease of operation
If base station transmits control messages including MAC_ID to all terminals on PDCCH, then terminals can identify their control information, but transmission efficiency of the entire system is reduced
Solution Approach 1:
The patent extracts the MAC_ID identification function from the main control message transmission path. Instead of including MAC_ID in every control message transmitted on PDCCH, the system separates identification information (transmitted once in high-power WSI broadcasts) from data control messages, allowing terminals to filter relevant messages using the pre-received identification data without requiring repeated MAC_ID transmissions.
Solution Approach 2:
The patent applies preliminary action by providing terminals with their MAC_ID and associated WSI information in advance through high-power broadcasts before regular data transmission. This preliminary provision of identification information allows terminals to efficiently filter and identify their own control messages during subsequent lower-power transmissions, eliminating the need for repeated MAC_ID inclusion in every message.
3Productivity
If all available Walsh codes are utilized in PDCH during each time interval, then data transmission capacity is maximized, but resource waste occurs when not all codes are needed
Solution Approach 1:
The patent implements dynamics by making Walsh code allocation adaptive rather than static. The system dynamically adjusts the number of Walsh codes allocated to PDCH based on actual data transmission needs, as indicated by the WSI information. When less data needs to be transmitted, fewer Walsh codes are activated, allowing terminals to efficiently identify and use only the necessary codes while leaving unused codes available for other purposes.
Solution Approach 2:
The patent applies parameter changes by varying the Walsh code space configuration based on transmission requirements. The WSI information conveys parameters about which Walsh codes are currently allocated and active, allowing the system to change the effective Walsh code space from the full set to a smaller subset when full capacity is not needed, thereby reducing resource waste while maintaining transmission capacity when required.
Data Source
AI summary
In a mobile communication system, an error detection code or a quality frame indicator (e.g., CRC) is generated using selectively frame information, and at least one of a WCA identifier of another terminal, and a corresponding terminal identifier. And the terminal identifier can be implicitly transmitted to the receiver.