SC-OFDM Preamble Patterns for Multipath Synchronization
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Solution Overview
Problem
In radio communication systems, particularly those using SC-OFDM, multipath fading affects preamble patterns, leading to uneven power distribution across subcarriers, which can result in failed reception synchronization due to reduced correlation peak power or incorrect timing detection.
Innovation Solution
A transmission apparatus generates and transmits at least two preamble patterns with bit series continued for different numbers of bits, such as n and k bits, ensuring power is not unevenly distributed across subcarriers, allowing accurate synchronization timing detection even in multipath fading environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If SC-OFDM method is used to reduce PAPR and power consumption, then power consumption is reduced, but multipath fading causes uneven power distribution across subcarriers leading to synchronization failures
Solution Approach 1:
The patent changes the parameter of preamble pattern by transmitting multiple different preamble patterns (first, second, and third patterns) instead of a single pattern. This allows the reception apparatus to select a pattern that was not affected by multipath fading, thereby maintaining synchronization reliability while using SC-OFDM for reduced power consumption
Solution Approach 2:
The system dynamically selects different preamble patterns based on reception conditions. The reception apparatus detects which preamble pattern achieved reliable correlation and uses that information for synchronization, making the system adaptable to multipath fading conditions rather than static
2Device complexity
If single preamble pattern is transmitted, then device complexity is reduced, but multipath fading reduces correlation peak power and causes incorrect timing detection
Solution Approach 1:
The patent introduces multiple preamble patterns with different characteristics (different bit continuations for n and k bits) to change the frequency domain parameters. This ensures that at least one pattern will have adequate power distribution even under multipath fading, improving timing detection precision without significantly increasing system complexity
3Manufacturing precision
If preamble pattern bits are continued for fixed number of bits, then manufacturing precision is simplified, but power becomes unevenly distributed across subcarriers in multipath fading environments
Solution Approach 1:
The patent creates asymmetric preamble patterns by continuing bits for different numbers (n bits and k bits where n≠k). This asymmetric structure ensures different frequency domain distributions for different patterns, preventing uniform multipath fading from affecting all patterns equally and ensuring reliable power distribution across subcarriers
Data Source
AI summary
A transmission apparatus for converting a transmission data series into frequency-domain, converting the frequency-domain converted signal into time-domain signal, and transmitting the time-domain converted signal, the apparatus including: a preamble pattern generation unit which outputs at least two preamble patterns among second and third preamble patterns, including bit series in which each of bits of a first preamble pattern is continued for n bits (where n is an integer equal to or greater than 2) and for k bits (where k is an integer equal to or greater than 2, and k≠n), and the first preamble pattern; and a transmission unit which transmits the transmission signal including at least two of the preamble patterns output from the preamble pattern generation unit.