Receiving Apparatus PN Sequence Removal Zero Padding
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Solution Overview
Problem
Existing receiving apparatuses face performance degradation and complexity due to multipath fading, particularly in ground wave broadcasting systems, where different PN modes lead to varying reference signal usage and increased hardware costs.
Innovation Solution
A receiving apparatus that removes the PN sequence from frame signals using a PN sequence remover and performs zero padding to align with discrete Fourier transform (DFT) size, allowing for data recovery through iterative block decision feedback equalization (IBDFE), which is applicable across various PN sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If different PN modes (PN 420, PN 595, PN 945) are used with different reference signal insertion strategies, then data recovery accuracy may be improved in specific multipath conditions, but hardware complexity increases due to requiring different DFT sizes (3780 DFT for PN 420/945, 4375 DFT for PN 595)
Solution Approach 1:
The patent applies universality by designing a single receiving apparatus that can handle all PN modes (PN 420, PN 595, PN 945) using a unified architecture. The key is using a fixed-size DFT unit (4375-point DFT) for all modes, with the understanding that PN 420 and PN 945 modes will have zero-padding applied to extend their 3780-point data to 4375 points. This eliminates the need for multiple specialized DFT units while maintaining optimal performance for each mode.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the input data length to the DFT unit based on the detected PN mode. For PN 420 and PN 945 modes, zero-padding is applied to extend the data length from 3780 to 4375 points before processing. For PN 595 mode, the full 4375-point data is processed directly. This parameter adaptation allows a single hardware unit to optimally process different modes.
2Reliability
If reference signals are removed in PN 420 and PN 945 modes to maintain cyclic structure, then multipath fading resistance is improved, but performance degradation occurs compared to PN 595 mode which retains reference signals
Solution Approach 1:
The patent converts the harmful effect of removing reference signals (which loses pilot information) into a benefit by using iterative block decision feedback equalization (IBDFE). The IBDFE algorithm iteratively refines data estimates using the cyclic structure and previously decoded data, effectively compensating for the absence of reference signals while maintaining robustness against multipath fading.
Solution Approach 2:
The patent implements feedback through the iterative block decision feedback equalization process. The IBDFE algorithm uses feedback from previously decoded data blocks to improve the estimation of current blocks, allowing the system to recover data accurately even without reference signals by leveraging the cyclic structure and iterative refinement.
3Adaptability or versatility
If zero padding is applied to extend data length to match DFT size, then uniform processing across PN modes is achieved, but additional processing time is required
Solution Approach 1:
The patent applies preliminary action by performing zero-padding early in the processing chain, immediately after frame synchronization and before the DFT operation. This preliminary extension of the data length ensures that the subsequent DFT and IBDFE operations can proceed uniformly for all PN modes without requiring different processing paths, thereby minimizing overall processing time despite the added padding step.
Data Source
AI summary
A receiving apparatus is provided. The receiving apparatus may include a receiver, a PN sequence remover, and a zero padding performing unit. The receiver may be configured to receive a frame signal. The PN sequence remover may be configured to remove a first PN sequence from a first frame detected from the frame signal corresponding to a first path to generate a PN removed first frame and remove a second PN sequence from a second frame detected from the frame signal corresponding to a second path to generate a PN removed second frame. The zero padding performing unit may be configured zero pad the first PN removed frame to a size of a discrete Fourier transform (DFT) and zero pad the PN removed second frame to the size of the DFT.