DCI Format 1A SPS C-RNTI Transmission Scheme Indication
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Solution Overview
Problem
The existing LTE systems face challenges in indicating a transmission scheme when a cyclic redundancy check code in a downlink control channel is scrambled with a Semi-Persistently Scheduled Cell Radio Network Temporary Identifier (SPS C-RNTI), particularly in supporting the double-flow beam forming technology introduced in LTE R9, which requires new transmission modes and signaling mechanisms.
Innovation Solution
The introduction of DCI Format 1A, which includes additional signaling bits to distinguish between single-layer transmission and transmit diversity, and to indicate the corresponding antenna port, ensuring flexibility in system scheduling without increasing complexity or overhead, while maintaining compatibility with LTE R8.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DCI Format 1A is used to indicate transmission schemes for SPS C-RNTI, then system scheduling flexibility is improved, but the complexity of the control information format increases
Solution Approach 1:
The patent applies multi-functionality by enabling DCI Format 1A to serve multiple transmission schemes (single-layer transmission and transmit diversity) through a single format structure. The format uses existing fields (MCS, NDI, RV) in combination with new indication bits to represent different transmission modes, allowing one control information format to handle multiple transmission scenarios without requiring separate dedicated formats for each mode.
Solution Approach 2:
The patent changes the interpretation parameters of existing DCI Format 1A fields to accommodate different transmission schemes. By modifying how the MCS, NDI, and RV fields are interpreted based on the transmission mode indication, the system achieves flexibility in supporting both single-layer and transmit diversity modes without adding significant complexity to the overall format structure.
2Measurement precision
If additional signaling bits are added to distinguish transmission schemes, then transmission scheme indication accuracy is improved, but the overhead of control information increases
Solution Approach 1:
The patent merges the transmission scheme indication function with existing DCI Format 1A fields rather than creating a completely separate signaling structure. The new indication bits are combined with existing MCS, NDI, and RV fields to jointly indicate different transmission modes, thereby achieving accurate transmission scheme indication while minimizing additional overhead by reusing existing control information elements.
Solution Approach 2:
The patent applies partial action by adding only the minimum necessary signaling bits (one or two bits) to distinguish between transmission schemes, rather than providing exhaustive signaling for all possible modes. This partial signaling approach, combined with field interpretation changes, achieves sufficient indication accuracy without excessive overhead.
3Reliability
If the system supports double-flow beam forming technology, then transmission performance is improved, but the complexity of the signaling mechanism increases
Solution Approach 1:
The patent makes the signaling mechanism universal by using DCI Format 1A to indicate both single-layer transmission and transmit diversity modes, which are required for double-flow beam forming. This multi-functional format allows the system to support advanced transmission techniques without requiring separate dedicated signaling mechanisms for each transmission mode, thereby improving transmission performance while controlling signaling complexity.
Solution Approach 2:
The patent introduces dynamic interpretation of control information fields based on the indicated transmission mode. The same fields (MCS, NDI, RV) have different meanings depending on whether the transmission is single-layer or transmit diversity mode, allowing the system to adaptively support double-flow beam forming through dynamic field interpretation rather than static dedicated signaling.
Data Source
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AI summary
The present disclosure discloses a method and system for transmitting downlink control information, for solving the problem of how to indicate a transmission scheme when a cyclic redundancy check code in the downlink control channel is scrambled with the semi-persistently scheduled cell radio network temporary identifier. In order to support the bi-flow beam forming technology in the LTE-A R9, the present disclosure provides a downlink control information Format 1A, which may, when the cyclic redundancy check code in the downlink control channel is scrambled with the semi-persistently scheduled cell radio network temporary identifier, indicates a method for transmitting downlink control information, for example, single-layer transmission, transmit diversity, or a transmission scheme simultaneously involving single-layer transmission and transmit diversity, which guarantees flexibility of system schedule. The present disclosure adds no signaling overhead and has good adaptability with the LTE R8.