OFDM Time Synchronization via Continuous Reference Signal
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Solution Overview
Problem
In OFDM or OFDMA wireless communication systems, the existing methods for acquiring time synchronization are time-consuming, leading to delayed communication preparation, increased power consumption, and prolonged handoff connections due to the need for repeated preamble acquisition and synchronization.
Innovation Solution
A method where a reference signal is modulated across a subset of subcarriers and transmitted continuously during at least one symbol time, allowing the receiving side to acquire time synchronization more efficiently by including information indicating the symbol time, thereby reducing unnecessary symbol searches and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a preamble signal is inserted with a uniform interval to enable time synchronization, then the receiving side can acquire time synchronization, but it takes a long time to tune the time synchronization until the preamble is read
Solution Approach 1:
The patent segments the synchronization function by introducing a new reference signal with symbol time information in addition to the existing preamble signal. This divides the synchronization acquisition process into two parts: coarse synchronization using the preamble and fine synchronization using the reference signal, thereby reducing the overall time required while maintaining accuracy
Solution Approach 2:
The reference signal containing symbol time information is transmitted continuously during at least one symbol time before data transmission begins. This preliminary action allows the receiving side to acquire time synchronization information in advance, eliminating the need to wait for periodically inserted preamble signals and significantly reducing synchronization acquisition time
2Measurement precision
If the receiving side repeatedly acquires preamble signals to tune time synchronization precisely, then synchronization accuracy is improved, but power consumption increases
Solution Approach 1:
The reference signal with symbol time information is provided in advance during the symbol time, allowing the receiving side to perform precise time synchronization without needing to repeatedly acquire and process multiple preamble signals. This reduces the number of repeated operations and consequently lowers power consumption
Solution Approach 2:
The patent extracts the symbol time information from the preamble signal and places it in a dedicated reference signal. This extraction allows the receiving side to obtain the necessary synchronization information more efficiently without the need for repeated preamble acquisition, thereby reducing power consumption
3Measurement precision
If the receiving side waits for the next preamble to tune time synchronization more precisely, then synchronization accuracy is improved, but connection delay in handoff is prolonged
Solution Approach 1:
The reference signal containing symbol time information is transmitted in advance during the symbol time, enabling the receiving side to perform precise time synchronization before data transmission begins. This eliminates the need to wait for the next periodically inserted preamble signal, significantly reducing handoff connection delay while maintaining synchronization accuracy
Data Source
AI summary
A method of acquiring time synchronization and supporting method for the same are provided. The present invention enables early synchronization of a receiving side with a transmitting side by avoiding time delays that may result in detecting a current preamble signal. The current preamble signal is inserted with a uniform interval to allow the receiving side to tune its time synchronization with the transmitting side or measure a signal strength in the orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) wireless communication system. In an OFDM or OFDMA wireless communication system, the present invention includes modulating a number of reference signals for time synchronization acquisition in a receiving side using at least one of a number of subcarriers and continuously transmitting at least one reference signal modulated by at least one subcarrier to the receiving side during at least one symbol time.