CDMA Receiver Sampling Control Module Synchronization
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Solution Overview
Problem
CDMA receivers face sampling errors and asynchronous output signals due to changes in transmission paths, leading to incorrect selection of optimal samples and increased signal processing burdens.
Innovation Solution
A CDMA receiver with a sampling control module that delays samples for different lengths and adjusts sampling and code generation trigger signals, using a single sampling trigger signal and despreading code to synchronize the decimation and demodulation of early, on-time, and late samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sampling trigger signals are used for early, on-time, and late samples, then sampling flexibility is improved, but system complexity and asynchronous output increase
Solution Approach 1:
The patent merges multiple sampling trigger signals into a single sampling trigger signal that is shared across all despreaders. This single trigger signal is used to control the sampling process for early, on-time, and late samples respectively, eliminating the need for separate trigger signals for each sample type and thereby reducing system complexity while maintaining sampling flexibility.
2Measurement precision
If separate sampling trigger signals are used for different samples, then sampling control precision is improved, but signal processing burden increases
Solution Approach 1:
The single sampling trigger signal serves multiple functions by being used to control the sampling of early, on-time, and late samples across different despreaders. This universal trigger signal reduces the overall signal processing burden while maintaining precise sampling control through the time tracking loop that adjusts sampling timings based on transmission path changes.
3Manufacturing precision
If timing adjustment is made for sampling, then optimal sample selection is improved, but sampling errors occur
Solution Approach 1:
The patent implements a feedback mechanism where the optimal sample decision module selects the optimal sample based on correlation values and generates a sampling timing adjustment signal. This feedback signal is then fed back to the sampling control module to adjust the sampling trigger signal timing, ensuring accurate sampling while maintaining optimal sample selection. The feedback loop continuously refines sampling timing to prevent sampling errors.
4Adaptability or versatility
If multiple despreaders process samples asynchronously, then processing flexibility is improved, but output signal synchronization is lost
Solution Approach 1:
The patent merges the control of multiple despreaders under a single sampling trigger signal, ensuring that all despreaders operate synchronously. The time tracking loop maintains synchronization by adjusting sampling timings across all despreaders, while the optimal sample decision module provides feedback to keep all outputs aligned. This unified control approach maintains output signal synchronization while preserving processing flexibility through the rake receiver's multiple fingers.
Data Source
AI summary
The invention provides a Code Division Multiple Access (CDMA) receiver for sampling a received CDMA signal into a plurality of samples. The CDMA receiver comprises a sampling control module, a code generator, and a plurality of despreaders. The sampling control module delays the samples for a plurality of different delay lengths to obtain a plurality of delayed samples respectively corresponding to each of the delay lengths, and adjusts timing of a sampling trigger signal and a code generation trigger signal according to a sampling timing adjustment signal. The code generator generates a despreading code according to the code generation trigger signal. Each of the despreaders is configured for decimating the delayed samples corresponding to each delay lengths according to the sampling trigger signal to obtain a plurality of decimated delayed samples, and despreads the decimated delayed samples with the despreading code to obtain a plurality of output signals.