Cell Searcher PSS Symbol Cancellation for Neighbor Detection
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Solution Overview
Problem
In the 3GPP LTE system, mobile terminals face reduced neighbor cell detection probability due to shared PSS codes between home and neighbor cells, leading to increased false alarm probabilities and limited applicability in asynchronous systems.
Innovation Solution
A cell searcher method for mobile terminals that cancels the PSS symbol of the home cell from the received signal in the time domain when the PSS codes are identical, allowing for neighbor cell detection regardless of synchronization, using techniques like channel coefficient estimation and Fourier transformations to enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the mobile terminal uses PSS codes for neighbor cell detection, then the detection process can be simplified, but the detection probability is reduced when home cell and neighbor cell share the same PSS code
Solution Approach 1:
The patent extracts and removes the harmful interference component (home cell PSS symbol) from the received signal before performing neighbor cell detection. By separating the home cell signal component and subtracting it from the total received signal, the detection process can use simple PSS correlation without suffering from home cell interference, thus maintaining low complexity while improving detection probability
Solution Approach 2:
The patent introduces an intermediate processing step between signal reception and PSS detection. The received signal first passes through a home cell PSS cancellation stage that uses estimated channel coefficients to remove the home cell contribution, creating a cleaned signal that serves as an intermediary for subsequent neighbor cell detection
2Productivity
If the mobile terminal performs real-time neighbor cell search, then handover speed is improved, but false alarm probability increases due to PSS code sharing
Solution Approach 1:
The patent applies preliminary anti-action by pre-canceling the home cell PSS symbol interference before the neighbor cell detection process begins. By estimating the home cell signal characteristics and removing them in advance, the system prevents false detections from occurring during the real-time search process, enabling fast handover without sacrificing detection accuracy
3Loss of information
If the mobile terminal detects SSS after acquiring PSS, then cell identification is achieved, but detection probability is reduced when PSS codes are identical between home and neighbor cells
Solution Approach 1:
The patent extracts the home cell PSS symbol interference from the received signal before SSS detection. By removing the dominant home cell signal component that would otherwise mask the weaker neighbor cell SSS signal, the system enables reliable SSS detection and cell identification even when PSS codes are shared between home and neighbor cells
Data Source
AI summary
Provided are a cell searcher for handover of a mobile terminal and a neighbor cell searching method thereof. The neighbor cell searching method includes: after searching a home cell, determining whether a Primary Synchronization Signal (PSS) code of the home cell is identical to that of a neighbor cell; when the PPS code of the home cell is identical to that of the neighbor cell, cancelling a PSS symbol of the home cell from a received signal in a time domain; and searching a neighbor cell from the received signal cancelled the PSS symbol of the home cell.