Common Scrambling Sequence for Seamless Mobility in Local Area Networks
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Solution Overview
Problem
Current cellular communication systems, such as W-CDMA and LTE, face challenges in supporting smooth mobility between local areas due to changes in scrambling sequences during handovers, which complicates cell planning and interferes with high-speed wireless services in local environments.
Innovation Solution
A communication system that employs a common scrambling sequence for data signals and reference signals across multiple local areas, eliminating the need for cell-specific IDs and simplifying cell planning by using a wide area's cell ID and C-RNTI for scrambling, ensuring seamless mobility without changes in scrambling when a mobile terminal moves between local areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If cell-specific scrambling sequences are used in each local area, then interference management between cells is improved, but mobility smoothness deteriorates due to scrambling changes during handover
Solution Approach 1:
The patent applies a universal scrambling sequence derived from wide area base station identifiers (cell ID and C-RNTI) across multiple local area base stations. This allows the same scrambling mechanism to serve both interference management functions and maintain mobility smoothness, eliminating the need for cell-specific scrambling variations that would disrupt handover processes.
2Adaptability or versatility
If cell-specific IDs are used for scrambling in each local area, then cell identification and interference coordination are improved, but device complexity increases due to multiple ID management
Solution Approach 1:
The patent extracts the essential identification function from local area cell-specific IDs and replaces it with identifiers from the wide area base station (cell ID and C-RNTI). This removes the complexity of managing multiple cell-specific identifiers while retaining the ability to identify and coordinate between cells through the wide area identifiers.
Solution Approach 2:
The wide area base station identifiers (cell ID and C-RNTI) are used to serve multiple functions: they identify the wide area base station, they identify the mobile terminal through C-RNTI, and they generate the scrambling sequence for local area communication. This multi-functionality eliminates the need for separate cell-specific IDs in local areas, reducing overall system complexity.
3Object-affected harmful factors
If different scrambling sequences are applied in different local areas, then local area interference management is improved, but network efficiency decreases due to frequent scrambling changes during mobility
Solution Approach 1:
The patent implements a universal scrambling approach where the same scrambling sequence generation method based on wide area identifiers is applied across all local areas. This maintains network efficiency by avoiding scrambling changes during handover while still providing interference management through the structured use of cell ID and C-RNTI in the scrambling sequence generation.
Data Source
AI summary
A system for supporting smooth mobility of a mobile terminal apparatus between a plurality of local areas that are arranged in a wide area is disclosed. The system includes a wide area base station apparatus that covers a wide area, a local area base station apparatus that covers a local area arranged in the wide area, and a mobile terminal apparatus that can communicate with the wide area base station apparatus and the local area base station apparatus, and is configured to scramble a data signal and a reference signal by a scrambling sequence that is common between a plurality of local areas in communication between the local area base station apparatus and the mobile terminal apparatus.