RF Front-End Parallel Cell Search Using Carrier Aggregation
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Solution Overview
Problem
The sequential nature of cell search frequency scans in 4G and 5G networks, due to the increasing number of frequency bands, results in prolonged scan times, affecting user experience and network connection speed.
Innovation Solution
Exploiting carrier aggregation capabilities of RF front-end circuitry to perform parallel frequency scanning and cell search operations, utilizing multiple receive paths and IQ width-based decision-making techniques to reduce scan time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sequential frequency band scanning is performed to ensure reliable cell search across all bands, then measurement precision is improved, but cell search time increases significantly
Solution Approach 1:
The patent segments the cell search process into two distinct phases: an initial fast scan phase that quickly identifies candidate frequency bands using simplified detection, followed by a precise measurement phase that performs accurate RSRP/RSRQ measurements only on the identified candidate bands. This segmentation allows the system to maintain measurement precision while dramatically reducing overall cell search time by avoiding exhaustive scanning of all frequency bands.
Solution Approach 2:
The patent performs preliminary frequency band identification before conducting detailed cell measurements. The fast scan phase pre-identifies candidate frequency bands by detecting synchronization signals or reference signals, allowing subsequent precise measurements to be focused only on these candidate bands rather than all possible bands, thus reducing total search time while maintaining accuracy.
2Reliability
If all frequency bands are scanned to ensure complete network coverage detection, then reliability is improved, but productivity decreases due to extended scan duration
Solution Approach 1:
The patent divides the frequency band scanning process into a preliminary fast scan stage and a detailed measurement stage. The fast scan stage quickly identifies candidate bands to ensure coverage detection, while the detailed stage performs reliable measurements only on these candidates. This segmentation maintains connection reliability by ensuring all candidate bands are identified while improving productivity by avoiding exhaustive scanning.
Solution Approach 2:
The patent performs partial scanning by focusing detailed measurements only on candidate frequency bands identified during the fast scan phase, rather than performing exhaustive measurements on all possible bands. This partial action approach maintains sufficient reliability for network connection by identifying all viable candidate bands while significantly improving productivity by reducing the total measurement workload.
3Speed
If multiple receive paths are utilized for parallel frequency scanning, then cell search speed is improved, but device complexity increases
Solution Approach 1:
The patent makes the RF front-end receive paths multi-functional by enabling them to operate in parallel for frequency band scanning in addition to their primary function of receiving data signals. The same receive paths that are used for normal cellular communication are utilized for the fast scan operation, eliminating the need for dedicated separate hardware and thus improving scan speed without significantly increasing device complexity.
Solution Approach 2:
The patent enables the existing RF front-end circuitry to serve dual purposes: normal signal reception and fast frequency band scanning. The receive paths automatically perform both functions using the same hardware resources, allowing parallel frequency scanning to improve speed while avoiding the complexity increase that would result from adding dedicated separate scanning hardware.
Data Source
AI summary
The present disclosure presents methods and devices configured to exploit the carrier aggregation (CA) capabilities of a radio frequency (RF) front-end (FE) of a terminal device to perform a frequency scan in cell search operations. Based on the CA options of the RF FE of the terminal device, one or more tables are stored in a memory of the terminal device, where the tables include frequency band search sets including multiple frequencies that can be scanned by the terminal device in parallel based its CA capabilities. When a frequency scan for a cell search operation is triggered, a processor of the terminal device is configured to retrieve one of the tables from the memory and perform the frequency scan of the cell search operation based on the frequency band search sets retrieved from the table in the memory.