WCDMA Noise Power Estimation Using Orthogonal Sequences
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Solution Overview
Problem
Conventional methods for calculating noise power in WCDMA networks result in biased estimates, which are often inaccurate, especially during handover scenarios where mobile handsets need to adjust transmit power to communicate with new cell sites effectively.
Innovation Solution
A method for computing noise power estimate in WCDMA networks involves generating orthogonal sequences based on the slot number and transmit diversity mode, summing dedicated physical channel pilot bits to create in-phase and quadrature components, squaring and normalizing these components to yield accurate noise power estimates for downlink channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods utilizing mean and/or variance are used to calculate noise power, then the calculation process is simple, but the estimate is biased and inaccurate
Solution Approach 1:
The patent changes the calculation parameters from conventional mean and variance to a method based on summing in-phase and quadrature components, multiplying by orthogonal sequence, squaring, and normalizing. This parameter transformation eliminates the bias in noise power estimation while maintaining computational feasibility through structured operations on pilot bits.
2Reliability
If accurate noise power estimation is achieved through new methods, then power control during handover is improved, but the computational complexity increases
Solution Approach 1:
The patent performs preliminary actions by pre-generating orthogonal sequences based on slot number and transmit diversity mode before the actual noise power calculation. This preparation step enables the subsequent calculation to proceed efficiently with pre-organized computational elements, reducing the burden during critical handover operations.
Solution Approach 2:
The calculation process is segmented into distinct operational stages: summing pilot bits to generate I and Q components, multiplying by orthogonal sequence to generate noise components, squaring the components, and normalizing by dividing by the number of pilot bits. This segmentation structures the computation to improve reliability while managing complexity through organized processing steps.
Data Source
AI summary
Method and apparatus for computing a noise power estimate in a wideband CDMA (WCDMA) network are disclosed and may include calculating a noise power estimate for a downlink channel based on an orthogonal sequence generated for a transmitted signal. The orthogonal sequence may be generated based on a slot number of the transmitted signal and/or a transmit diversity mode used for the transmitted signal. A portion of a plurality of dedicated physical channel (DPCH) pilot bits for the downlink channel may be summed to generate an in-phase (I) component and a quadrature (Q) component. The generated I component and the generated Q component may be multiplied by the orthogonal sequence to generate at least one noise I component and at least one noise Q component.