Symbol Clock Synchronization With Offset Initialization
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Solution Overview
Problem
Existing symbol clock synchronization methods in data transmission systems, such as feedback symbol synchronizers, suffer from long settling times due to narrow control bandwidth requirements, which is a trade-off with low inherent noise.
Innovation Solution
A device comprising an estimation component and a feedback symbol synchronizer, where the estimation component estimates phase and frequency offsets between the transmitter and receiver symbol clocks, allowing for initialization of the symbol synchronizer to reduce settling time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a feedback symbol synchronizer is used to achieve low inherent noise, then the noise level is reduced, but the settling time increases due to narrow control bandwidth requirements
Solution Approach 1:
The invention applies preliminary action by using a feedforward symbol synchronizer to estimate phase and frequency offsets before the feedback symbol synchronizer begins operation. This preliminary estimation allows the feedback synchronizer to start with pre-synchronized parameters, significantly reducing its settling time while maintaining the low noise characteristics of the feedback approach.
2Reliability
If the control bandwidth is narrowed to reduce inherent noise, then the noise level decreases, but the settling time increases
Solution Approach 1:
The feedforward symbol synchronizer performs preliminary phase and frequency offset estimation before the feedback synchronizer operates. This allows the narrow-band feedback synchronizer to start from a pre-synchronized state rather than requiring wide bandwidth for fast acquisition, thus achieving both low noise and fast settling.
Solution Approach 2:
The synchronization process is segmented into two distinct stages: a feedforward stage for rapid preliminary synchronization using wide bandwidth, and a feedback stage for fine-tuning with narrow bandwidth. This segmentation allows each stage to be optimized for its specific function without the trade-off present in a single-stage system.
3Loss of time
If a feedforward symbol synchronizer is used to achieve faster synchronization, then the settling time is reduced, but the hardware and software resource requirements increase
Solution Approach 1:
The synchronization function is segmented between a simple feedforward estimator and a feedback synchronizer. The feedforward component uses basic correlation operations on known preamble sequences, requiring minimal resources, while the feedback component handles the complex adaptive filtering. This segmentation achieves fast synchronization without requiring a fully resource-intensive feedforward system.
Solution Approach 2:
The feedforward symbol synchronizer performs a simplified preliminary estimation using only the known preamble structure, avoiding the need for complex adaptive algorithms during the initial synchronization phase. This preliminary action reduces the computational burden compared to using a full feedforward synchronizer throughout the entire process.
Data Source
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AI summary
The present invention relates to a device (5) for synchronizing a symbol clock during data transmission and to a transmission system, the device comprising: an estimation component (30) and a symbol synchronizer (40), the estimation component (30) being configured to receive a first signal (S1) generated by the transmitter (10) and, on the basis of the first signal, to estimate a phase offset (POFF) and/or a frequency offset (FOFF) between a symbol clock of the transmitter (10), on the basis of which the first signal (S1) is generated, and a symbol clock of the receiver (S2), on the basis of which the first signal (S1) is evaluated in the receiver (20), the device (5) being configured to initialize the symbol synchronizer (40), which is designed as a feedback symbol synchronizer (40), on the basis of the estimated phase offset (POFF) and/or the estimated frequency offset (FOFF),and wherein the symbol synchronizer (40) is configured to receive a second signal (S2) generated by the transmitter (10) in order to generate, on the basis of the second signal (S2), an output signal (S0) representing symbols synchronized with the symbol clock of the receiver (20) that are transmitted within the second signal (S2).