Slot-Specific Cyclic Delay Diversity for Wireless Signal Diversity
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Solution Overview
Problem
Current wireless communication technologies, such as 5G NR and LTE, face challenges in improving spectral efficiency and coverage for physical downlink and uplink shared channels due to the lack of frequency diversity in slot aggregation techniques.
Innovation Solution
Implementing slot-specific cyclic delay diversity (CDD) by applying different phase delays for OFDM tones across multiple slots, which enhances frequency diversity and improves signal reception by creating distinct channels for each tone, even if the raw tone channel remains the same.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If slot aggregation is used to improve coverage, then reliability is improved, but frequency diversity is lost because the same frequency resources are reused in each slot
Solution Approach 1:
The patent applies cyclic delay diversity by introducing different cyclic delay parameters across multiple slots. Specifically, each slot uses a different cyclic delay value (e.g., based on slot index or configured patterns), which transforms the transmitted signal in the time domain and creates frequency diversity while maintaining the slot aggregation structure for reliability
2Productivity
If the same frequency resources are reused in each slot for slot aggregation, then spectral efficiency is improved, but the system becomes vulnerable to frequency-selective fading
Solution Approach 1:
The patent introduces cyclic delay as a varying parameter across slots to combat frequency-selective fading. By applying different cyclic delays in different slots, the system ensures that frequencies experiencing fading in one slot may be transmitted with different delays in other slots, providing diversity protection while maintaining resource efficiency
Data Source
AI summary
Certain aspects of the present disclosure provide techniques for increasing diversity of transmissions with slot aggregation using slot-specific cyclic delay diversity (CDD). A method that may be performed by a transmitting device includes determining to transmit a signal using cyclic delay diversity (CDD) in a plurality of slots; and transmitting the signal using a different cyclic delay in each slot of the plurality of slots.