Phase Noise Compensation in SC-FDE Receivers
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Solution Overview
Problem
In ultra-high frequency bands, phase noise significantly degrades system performance due to increased phase noise characteristics, particularly in millimeter wave communication systems using SC-FDE schemes, leading to performance issues with high-order modulation schemes like 64 QAM.
Innovation Solution
The method involves estimating phase noise in the time domain by combining unique word (UW) signals from consecutive data blocks with weighted combining, applying time-domain compensation, and varying the UW length based on modulation and coding schemes to improve phase noise compensation without increasing hardware complexity or causing additional time delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If frequency multiplier is used to achieve high carrier frequency in ultra-high frequency band, then carrier frequency is improved, but phase noise increases by 20 Log 10K
Solution Approach 1:
The patent applies preliminary action by estimating phase noise using unique words (UW) transmitted before the actual data blocks. The phase noise is estimated in advance using the UW signals from multiple data blocks, allowing the receiver to compensate for phase noise effects before processing the actual data, thereby mitigating the harmful phase noise introduced by frequency multiplication.
Solution Approach 2:
The patent implements feedback by using the estimated phase noise to compensate for the actual received signals. The receiver estimates phase noise from UW signals and then applies compensation to the data blocks, creating a feedback loop that continuously adjusts for phase noise effects, effectively counteracting the harmful phase noise introduced by the frequency multiplier.
2Reliability
If phase noise compensation is applied to maintain system performance, then reliability is improved, but receiver complexity increases
Solution Approach 1:
The patent extracts the phase noise estimation function from the main data processing path by using separate unique word (UW) signals transmitted in data blocks. This allows phase noise to be estimated independently using dedicated UW signals, separating the compensation function from the data decoding process and reducing the complexity of the overall receiver system.
Solution Approach 2:
The patent makes the unique word (UW) signals serve multiple functions: they act as both frame delimiters for data block identification and as phase noise estimation references. This multi-functionality reduces the need for separate reference signals and simplifies the receiver structure while maintaining reliable phase noise compensation.
3Measurement precision
If unique word length is increased to improve phase noise estimation accuracy, then measurement precision is improved, but overhead increases
Solution Approach 1:
The patent applies partial action by using a limited number of unique word (UW) signals from multiple data blocks for phase noise estimation, rather than requiring continuous or excessive UW signals. The receiver uses UW signals from a manageable number of data blocks to achieve sufficient phase noise estimation accuracy, avoiding excessive overhead while maintaining precision.
Solution Approach 2:
The patent makes the UW period length variable rather than fixed, allowing the system to adapt the number of UW signals used for estimation based on actual channel conditions and requirements. This dynamic adjustment enables the system to use only the necessary amount of UW signals for adequate phase noise estimation, reducing overhead when high precision is not required.
Data Source
AI summary
An operation method of a receiving apparatus may comprise: receiving an N-th data block belonging to a frame including a plurality of data blocks from a transmitting apparatus, each of the plurality of data blocks including a data period and a UW period; storing a first UW received in a UW period of the N-th data block in a buffer; receiving an (N+1)-th data block belonging to the frame from the transmitting apparatus; estimating a phase noise in a time domain by combining the first UW with a second UW received in a UW period of the (N+1)-th data block; and applying time-domain compensation according to the estimated phase noise to the (N+1)-th data block, and demodulating data of the (N+1)-th data block, wherein the first UW and the second UW are configured with a same sequence.