TD-SCDMA Handover Decision Algorithm Using Interference Metrics
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Solution Overview
Problem
Current TD-SCDMA systems face challenges in selecting the best cell during inter-frequency handover, as the traditional method using P-CCPCH RSCP does not accurately reflect low interference, leading to potential link deterioration due to over-capacity or coverage issues, and lacks a decision algorithm for inter-system handovers.
Innovation Solution
A decision algorithm that selects a cell based on capacity and coverage metrics, using received signal code power and interference levels to determine the best handover option, with metrics such as PRSC/(IRSS-PRSC) for capacity and PRSC for coverage, to minimize admission cost and ensure reliable communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If P-CCPCH RSCP is used as the handover decision metric, then the handover process is simple and fast, but it does not accurately reflect interference levels leading to link deterioration
Solution Approach 1:
The patent changes the handover decision parameter from P-CCPCH RSCP alone to a composite metric that incorporates both RSCP and interference measurements (ICH0, ICH1, ICH2). This parameter change enables accurate interference assessment while maintaining practical implementability through standardized measurement procedures.
Solution Approach 2:
The patent creates a composite handover metric that combines multiple measurement components (RSCP, ICH0, ICH1, ICH2) into a unified decision framework. This composite approach类似于creating a new material with properties that neither component alone could provide, achieving both accuracy and practicality.
2Productivity
If inter-frequency handover is performed frequently to prevent over-capacity, then network capacity is maintained, but handover overhead and potential link deterioration increase
Solution Approach 1:
The patent implements a feedback mechanism where the handover decision metric continuously incorporates latest interference measurements (ICH0, ICH1, ICH2) and signal strength (RSCP). This feedback loop enables the system to respond dynamically to changing network conditions, maintaining capacity while preventing unnecessary handovers that could deteriorate link quality.
Solution Approach 2:
The patent performs preliminary interference assessments using multiple measurement components before executing handover decisions. By evaluating the composite metric in advance, the system可以避免premature or inappropriate handovers, ensuring that handovers occur only when truly beneficial for maintaining link reliability.
3Ease of operation
If hard handover is used to connect UE to single best cell, then connection management is simplified, but coverage continuity and reliability are reduced
Solution Approach 1:
The patent introduces dynamic evaluation of handover candidates using a comprehensive metric that considers both signal strength and interference from multiple sources (ICH0, ICH1, ICH2). This dynamic assessment enables the system to select the truly best cell at each moment, improving the effectiveness of hard handover while maintaining its operational simplicity.
Data Source
AI summary
A method for determining whether to perform handover of a UE apparatus to a candidate cell and carrier frequency of a TD-CDMA telecommunications network (such as a TD-SCDMA network) based separately on coverage and capacity, using one decision metric for coverage (e.g. based on received signal code power for the candidate cell and carrier frequency) and a different decision metric for capacity (e.g. based on a quantity proportional to the received signal code power for the candidate cell and carrier frequency and inversely proportional to a measure of total interference in the candidate cell on the carrier frequency. Corresponding equipment and a computer program product are also provided. In deciding whether handover is needed based on capacity, a threshold for received signal code power may be used in addition to the metric for capacity.