UWB-IR Receiver Synchronization via Two-Stage Phase Search
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Solution Overview
Problem
The UWB-IR communication system faces challenges in achieving rapid and accurate initial synchronization acquisition with high precision, while maintaining low power consumption and small hardware complexity, due to its use of extremely narrow pulse width and intermittent signal transmission.
Innovation Solution
A receiving apparatus with an initial synchronization acquiring device that includes a peak search function for finding the largest output value across all phases and a detailed synchronization acquiring function for refining the peak phase estimation, allowing for accurate pulse timing search with controlled analog-to-digital conversion frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pulse width is made extremely narrow to expand signal spectrum and spread signal energy, then frequency band utilization is improved and interference is reduced, but signal energy per unit frequency band becomes very small making synchronization acquisition difficult
Solution Approach 1:
The patent segments the synchronization acquisition process into two distinct stages: a rough acquisition stage that searches for the signal within a wide frequency range, and a fine acquisition stage that precisely determines the synchronization point. This segmentation allows the system to first locate the signal despite its low energy density, then refine the timing accuracy, thereby resolving the contradiction between narrow pulse width and synchronization precision.
Solution Approach 2:
The patent performs preliminary signal detection and rough synchronization acquisition before attempting fine timing measurement. By first identifying the presence and approximate location of the pulse train signal through preliminary actions, the system prepares the reception apparatus to accurately measure the precise synchronization point, overcoming the difficulty posed by extremely narrow pulse widths.
2Use of energy by moving object
If the signal transmission is made intermittent with extremely narrow pulse width, then power consumption is reduced and frequency band sharing is enabled, but initial synchronization acquisition becomes more difficult and time-consuming
Solution Approach 1:
The patent maintains continuous monitoring and correlation operations during the synchronization acquisition phase, continuously processing the received signal to detect pulse arrivals. This continuous useful action ensures that despite the intermittent nature of the transmitted pulse train, the receiver can efficiently accumulate evidence of signal presence and rapidly achieve synchronization, reducing the time loss.
Solution Approach 2:
The system performs preliminary rough acquisition to quickly identify the signal's temporal location before fine timing measurement. This preliminary action significantly reduces the search space and acquisition time, enabling the system to handle intermittent narrow pulse transmissions efficiently without excessive time loss.
3Device complexity
If the hardware complexity is reduced to keep the apparatus small scale, then cost and power consumption are lowered, but the ability to achieve rapid and accurate synchronization acquisition is compromised
Solution Approach 1:
The patent segments the synchronization acquisition function into distinct rough and fine acquisition stages, each implemented with hardware complexity appropriate to its requirements. The rough acquisition stage uses simpler correlation operations to quickly locate the signal, while the fine acquisition stage employs more precise measurement techniques only when needed. This segmentation achieves rapid and accurate synchronization without requiring the entire system to be highly complex.
Solution Approach 2:
The synchronization acquisition apparatus uses the received pulse train signal itself as the reference for correlation operations, rather than requiring an external or pre-generated reference signal. This self-service approach eliminates the need for additional reference signal generation hardware, reducing device complexity while maintaining acquisition speed and accuracy.
Data Source
AI summary
The present invention conducts the initial synchronization acquisition of the rapid and high precision ultra-wideband signal without complicatedness of hardware and increase in power consumption. For this purpose, a communication apparatus for exchanging information with an intermittent pulse train signal searches all phases among the pulses in the predetermined search resolution in the process to acquire initial synchronization of the input pulse, estimates the region where the peak phase of the largest output value exists, narrows the region where the peak phase exists up to the predetermined range by repeating the search for all phases in the estimated region in the next step, and conducts acquisition of detailed synchronization in the estimated region. In every step, the threshold value for judging existence of signal or a gain in the analog circuit is controlled for each step. Moreover, the search resolution is set coarse for estimation of the peak phase and set fine for acquisition of detailed synchronization.