Cyclic Shift Sequence Generation for Interference Prevention
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Solution Overview
Problem
In radio communication systems, cyclic shift sequences with different bandwidths and high cross-correlation between cells lead to interference, degrading channel estimation accuracy, as orthogonality is not established between sequences with varying sequence lengths, causing interference peaks to be detected in desired wave detection windows.
Innovation Solution
The method involves generating cyclic shift sequences with distinct cyclic shift intervals for sequences within a cell and between cells, calculating a sum of cyclic shifts to differentiate between them, and using this sum to generate and transmit reference signals, allowing the base station to separate desired and interference waves by adjusting the detection window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cyclic shift sequences with different bandwidths are allocated between cells, then sequence reuse factor increases, but interference occurs between sequences with high cross-correlation, degrading channel estimation accuracy
Solution Approach 1:
The patent applies local quality by differentiating cyclic shift interval configurations between intra-cell and inter-cell scenarios. Within a cell, sequences use a first cyclic shift interval, while between cells, sequences use a second cyclic shift interval. This localized differentiation ensures that high cross-correlation sequences are avoided between cells while maintaining sequence reuse, thereby preventing interference in detection windows and preserving channel estimation accuracy.
2Productivity
If sequences of high cross-correlation are allocated to different cells, then more sequences can be reused across the system, but interference peaks appear in detection windows, causing detection errors
Solution Approach 1:
The patent changes the cyclic shift interval parameter differently for intra-cell and inter-cell sequence allocation. By setting the first cyclic shift interval for sequences within a cell and the second cyclic shift interval for sequences between cells, the system optimizes sequence distribution to avoid high cross-correlation interference while maximizing sequence reuse efficiency.
Data Source
AI summary
Provided is a cyclic shift sequence generation method which can prevent coming of an interference wave into a desired wave detection window even if a cyclic shift sequence has a high mutual correlation in different bandwidths, thereby improving a channel estimation accuracy in a base station. In this method, a cyclic shift sequence number to be allocated to a cell is decided in advance. Moreover, when the cyclic shift amount between cyclic shift sequences allocated in cells is Δ1 and the cyclic shift amount of the cyclic shift sequences allocated between the cells is Δ2, Δ1 and Δ2 are made different when generating a cyclic shift sequence.