Variable OFDM Preamble Structure for Burst Data Throughput
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Solution Overview
Problem
Conventional OFDM WLAN systems have inefficient data bandwidth utilization due to the fixed duration and prevalence of preamble fields, which dominate the signal and limit data throughput, especially for bursts with variable payload lengths.
Innovation Solution
The system reduces the number of preamble fields relative to payload fields in OFDM signal bursts, incorporating training sequences and adaptive control of receiver gain based on signal quality feedback, allowing for dynamic adjustment of burst structure and inter-frame gaps to optimize data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of preamble fields is increased to ensure reliable signal acquisition, then signal reception reliability is improved, but data bandwidth utilization deteriorates
Solution Approach 1:
The patent applies dynamics by making the number of preamble fields variable rather than fixed. The system dynamically adjusts the number of preambles (m) and payload fields (n) based on signal quality feedback, allowing optimization between reliability and bandwidth utilization for different transmission conditions
Solution Approach 2:
The patent changes the parameter of preamble field count from a fixed value to a variable parameter that can be adjusted based on signal quality. By allowing m (number of preambles) and n (number of payload fields) to vary, the system can adapt to different signal conditions and optimize the trade-off between acquisition reliability and data throughput
2Reliability
If fixed duration preambles are used for signal acquisition, then receiver synchronization is improved, but effective data transmission time is reduced
Solution Approach 1:
The patent makes the preamble duration dynamic by varying the number of preamble fields (m) based on signal quality feedback. Instead of using a fixed number of preambles for all transmissions, the system adjusts m to match actual signal conditions, reducing unnecessary preamble time when signal quality is good
Solution Approach 2:
The patent applies partial action by using fewer preambles than the maximum required when signal quality is sufficient. Rather than always using the full complement of preambles for synchronization, the system uses only the necessary number (m) based on actual signal conditions, thereby reducing overall transmission time
3Adaptability or versatility
If variable payload lengths are transmitted, then data throughput flexibility is improved, but signal structure complexity increases
Solution Approach 1:
The patent uses feedback from signal quality measurements to control the signal structure. The receiver provides feedback about signal quality, which the transmitter uses to adjust the number of preambles (m) and payload fields (n), creating a closed-loop system that adapts to channel conditions while managing complexity
Solution Approach 2:
The patent makes the signal structure dynamic by allowing the numbers of preambles (m) and payload fields (n) to vary based on feedback conditions. This dynamic adaptation allows the system to handle variable payload lengths efficiently while managing structural complexity through algorithmic control
Data Source
AI summary
A signal, and transmitters and receiver therefor, comprises a plurality of signal bursts each comprising m preamble fields, n payload fields, and n signal fields; wherein m<n; wherein each of the m preamble fields comprises a plurality of training sequences; wherein each of the n payload fields is preceded by one of the n signal fields; wherein each one of the n signal fields comprises information describing the following one of the n payload fields, and preamble data, wherein the preamble data in one of the n payload fields is set to a predetermined value only when one of the m preambles occurs between the one of the n signal fields and the next one of the n signal fields.