Measurement Gap Mapping for Cross-RAT Neighbor Cell Detection
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Solution Overview
Problem
Current mobile communication devices face challenges in efficiently performing neighbor cell measurements across different radio access technologies, particularly due to varying measurement gap durations and ambiguous reporting deadlines, which can lead to unpredictable detection of signal strength and base station identity in GSM systems when using LTE measurement gaps.
Innovation Solution
A method in user equipment (UE) that involves repeated mapping of measurement intervals to align with the transmission intervals of neighboring radio access networks, ensuring non-overlapping usage of measurement gaps to efficiently receive and store information from different radio access technologies, including the use of first, second, and third mapping processes to handle varying recurrence intervals and idle blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LTE measurement gaps are used for GSM neighbor cell measurements, then measurement opportunities are provided, but the detection of GSM signals becomes unpredictable due to mismatched timing and duration
Solution Approach 1:
The patent dynamically adjusts measurement gap parameters (timing and duration) based on the specific requirements of the target radio access technology. For GSM measurements, the system configures measurement gaps with timing aligned to GSM frame structures and duration sufficient to capture complete signal information, rather than using fixed LTE gap parameters. This parameter adaptation resolves the contradiction by making detection predictable while maintaining measurement efficiency.
Solution Approach 2:
The system implements dynamic selection and configuration of measurement gaps based on the camped RAT and target measurement requirements. When camped on LTE and measuring GSM cells, the system activates specific measurement gap patterns optimized for GSM timing structures. This dynamic adaptation ensures that measurement opportunities are reliably available for each RAT type while maintaining overall measurement efficiency across multiple technologies.
2Device complexity
If measurement gaps are shared across multiple radio access technologies, then measurement resources are optimized, but measurement deadlines cannot be met for all cells
Solution Approach 1:
The patent segments measurement gaps into technology-specific or purpose-specific allocations rather than using a completely shared pool. Measurement gaps are divided into sets optimized for different RATs (GSM, LTE, WCDMA) or different measurement types (BSIC identification, RSSI measurement, reconfirmation). This segmentation ensures that each measurement type has dedicated time resources meeting its deadline requirements, while the overall system remains relatively simple through automated gap selection based on current measurement needs.
3Reliability
If BSIC identification requires continuous time of 97 GSM slots, then guaranteed detection is achieved, but LTE measurement gaps of 6 milliseconds are insufficient
Solution Approach 1:
The system performs preliminary identification of potential GSM neighbor cells using available measurement gaps before committing to extended measurement periods. Initial detection uses shorter LTE-style gaps to identify candidate cells, then triggers dedicated BSIC identification measurements with properly timed and durationed gaps configured for GSM requirements. This preliminary action allows the system to prepare for guaranteed detection by pre-identifying targets that will require the full 97-slot measurement period.
Solution Approach 2:
The patent implements periodic measurement opportunities with different characteristics: shorter periodic gaps for initial cell detection and signal strength measurement, and longer periodic gaps configured for complete BSIC identification when needed. The system alternates between these periodic measurement patterns based on measurement state and requirements, achieving both efficient periodic monitoring and guaranteed detection when necessary.
Data Source
AI summary
An efficient way is described for a user equipment, camping on a cell of a first radio access technology, RAT, to perform measurements on the transmissions from a neighboring radio cell of a different RAT. Recurrent time gaps that are available for making the measurements are not correlated or synchronized with the recurrent times at which the desired information are transmitted by the transmitter in the second RAT. Therefore, mapping is performed of the time gaps onto the interval at which the desired information is transmitted. The mapping continues until a time interval is covered that ensures that the information in the recurring desired block of information can be obtained. During the mapping of the measurement gaps, only those time intervals that have not already been covered by the mapping are used for obtaining the desired information.