Dynamic CDM OFDM Slot Selection for Wireless Throughput
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Solution Overview
Problem
Wireless communication systems face challenges in improving bandwidth utilization and supporting advanced communication techniques like MIMO and SDMA while maintaining backward compatibility with existing terminals.
Innovation Solution
The implementation of a slot structure that selectively uses CDM or OFDM for each traffic segment, allowing for efficient data transmission and reception, with OFDM providing better spatial interference management and spectrum utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OFDM is used to improve bandwidth utilization and support spatial techniques, then spectral efficiency and link throughput are improved, but backward compatibility with existing terminals is compromised
Solution Approach 1:
The slot is divided into multiple traffic segments, where each segment can independently use CDM or OFDM. This allows the system to maintain compatibility with existing terminals for segments using CDM while enabling advanced spatial techniques for segments using OFDM, thus resolving the contradiction between backward compatibility and improved throughput.
Solution Approach 2:
Different traffic segments are assigned different modulation techniques (CDM or OFDM) based on local requirements. Segments can be selectively optimized for either compatibility or advanced spatial processing, allowing the system to achieve both backward compatibility and improved spectral efficiency in different parts of the transmission.
2Productivity
If spatial techniques like MIMO and SDMA are employed to improve throughput, then bandwidth utilization is improved, but system complexity increases
Solution Approach 1:
The transmission is divided into multiple traffic segments that can be processed independently. This segmentation allows the system to apply complex spatial processing only to segments that benefit from it, while keeping other segments simpler, thus managing overall system complexity while improving throughput.
Solution Approach 2:
The system dynamically selects between CDM and OFDM for each traffic segment based on current conditions. This dynamic adaptation allows the system to use complex spatial techniques only when beneficial, avoiding unnecessary complexity in scenarios where simpler CDM is sufficient.
Data Source
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Figure 3A~3B
AI summary
Techniques for efficiently sending data in a wireless communication system are described. Code division multiplexing (CDM) or orthogonal frequency division multiplexing (OFDM) may be selected for each traffic segment, which may correspond to specific time frequency resources. An output waveform comprised of traffic and overhead segments may be generated. Each traffic segment may carry CDM data at a chip rate if CDM is selected or OFDM data if OFDM is selected. OFDM symbols may be generated at a sample rate that may be an integer ratio of the chip rate and may have a duration that may be determined based on the traffic segment duration. The output waveform may carry CDM data and/or OFDM data on subcarriers corresponding to at least one carrier in a spectral allocation and may further carry OFDM data on remaining usable subcarriers in the spectral allocation.