DCI Overhead Reduction via Compressed DMRS Port Indicators
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Solution Overview
Problem
Current cellular communication systems face challenges in efficiently managing Downlink Control Information (DCI) overhead, particularly in supporting Multiuser-Multiple Input Multiple Output (MU-MIMO) and Single User MIMO (SU-MIMO) transmissions, leading to resource shortages and increased complexity.
Innovation Solution
The introduction of new DCI formats that utilize a DeModulation Reference Signal (DMRS) with a minimum payload size, a DMRS port indication field, and restrictions on resource allocation to localized or distributed Resource Blocks (RBs) to reduce DCI overhead, along with the use of a high-speed downlink grant flag and compressed DMRS port indicators, allowing for efficient switching between SU-MIMO and MU-MIMO modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If new DCI formats are introduced to support MU-MIMO with DMRS, then the system's ability to support multiuser transmissions is improved, but the DCI overhead increases
Solution Approach 1:
The patent introduces a universal DMRS port indication field that serves multiple functions: it identifies DMRS ports for both SU-MIMO and MU-MIMO transmissions, indicates the number of antenna ports, and supports different transmission modes. This multi-functional approach allows the system to support MU-MIMO versatility while using a compact field representation that minimizes DCI overhead.
Solution Approach 2:
The patent employs parameter changes by using a compressed DMRS port indicator that dynamically adjusts its representation based on the transmission mode. For SU-MIMO, it uses one set of parameter interpretations, while for MU-MIMO, it uses another set, allowing the same field to convey different information efficiently. This parameter adaptation reduces the average DCI overhead while maintaining full MU-MIMO capability.
2Quantity of substance
If resource allocation is restricted to localized RBs, then DCI overhead is reduced, but the flexibility of resource allocation is limited
Solution Approach 1:
The patent applies preliminary action by pre-configuring resource allocation parameters through higher-layer signaling (RRC) before actual data transmission. The DCI format only needs to indicate deviations from these pre-configured parameters, significantly reducing DCI overhead. This preliminary configuration maintains allocation flexibility because the pre-configured parameters can include multiple RB patterns and allocation schemes, while the actual DCI messages remain compact.
3Adaptability or versatility
If a DMRS port indication field is introduced to support both SU-MIMO and MU-MIMO, then the system's transmission mode versatility is improved, but the DCI payload size increases
Solution Approach 1:
The patent applies asymmetry by designing the DCI format with different interpretation rules for different transmission modes. The same DMRS port indication field is interpreted differently depending on whether SU-MIMO or MU-MIMO is active. This asymmetric design allows a single field to serve multiple purposes without requiring separate fields for each mode, thereby increasing versatility while minimizing payload size through efficient field reuse.
4Measurement precision
If the number of antenna ports is indicated explicitly, then the accuracy of transmission configuration is improved, but the DCI overhead increases
Solution Approach 1:
The patent uses the DMRS port indication field as an intermediary that indirectly conveys antenna port information. Instead of explicitly signaling the number of antenna ports with dedicated bits, the field serves as a mediator that references pre-configured antenna port settings. This intermediary approach maintains configuration accuracy by precisely identifying the intended antenna ports while avoiding the overhead of explicit numerical representation.
Data Source
AI summary
A method and apparatus are provided for transmitting and receiving Downlink Control Information (DCI) in a wireless communication system. A method includes generating downlink control information including an antenna port indicator comprising antenna port information and scrambling identity information; and transmitting, to a terminal, the downlink control information and data associated with the downlink control information. The scrambling identity information indicates one of two scrambling sequences, if a number of antenna ports indicated by the antenna port information is one and one transport block is enabled.