Adaptive Delay Diversity for Uplink Signal Optimization
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Solution Overview
Problem
Communication devices using multiple transmit chains for high-power modes often experience signal cancellation and elevated current drain, leading to reduced communication performance and battery life, especially in scenarios where higher power class operation does not significantly improve uplink communication quality or user experience.
Innovation Solution
The implementation of cyclic delay diversity (CDD) or linear delay diversity (LDD) between independent transmit chains, which configures and optimizes phase shifts or time delays to enhance uplink signal quality without increasing transmit power, thereby reducing the likelihood of signal cancellation and current drain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple transmit chains are operated simultaneously for high-power modes, then transmit power is increased, but signal cancellation occurs and current drain is elevated
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the phase shift values applied to different transmit chains based on measured channel conditions. The device determines optimal phase shifts that prevent signal cancellation while maintaining high transmit power, thereby resolving the contradiction between power output and communication reliability.
Solution Approach 2:
The patent implements feedback mechanisms where the device measures channel quality indicators (CQI) and uplink signal quality, then uses this feedback to adjust phase shift parameters in real-time. This closed-loop control ensures that multiple transmit chains operate cooperatively without causing signal cancellation, maintaining both high power and reliable communication.
2Power
If multiple transmit chains are operated simultaneously for high-power modes, then transmit power is increased, but current drain is elevated
Solution Approach 1:
The patent applies partial action by selectively activating only the necessary number of transmit chains based on current communication requirements and channel conditions. Rather than always operating all available transmit chains at full power, the device dynamically adjusts the number and configuration of active chains, reducing current drain while maintaining adequate transmit power when needed.
3Power
If higher power class operation is used, then uplink signal strength is increased, but signal cancellation may occur depending on antenna and channel correlation
Solution Approach 1:
The patent applies asymmetry by introducing deliberate asymmetric phase shifts between transmit chains that are optimized for the specific channel conditions. Rather than using symmetric or identical transmission patterns that may cause cancellation, the device employs asymmetric phase relationships that exploit channel characteristics to prevent cancellation while maintaining high uplink signal strength.
Data Source
AI summary
A communication device, method, and computer program product optimize cyclic or linear delay diversity for effective transmit diversity that increases transmit power by first and second transmit chains of the communication device while configured for uplink full power transmission mode 1. Using a precoding matrix codebook for multiple-input multiple-output transmission, a controller of the communication device sequentially configures the first transmit chain to transmit an uplink signal and the second transmit chain to transmit the uplink signal with a different phase shift or time delay value. While sequentially transmitting, the controller monitors a measure of uplink signal quality at a network node for each sequentially changed phase shift or time delay values. The controller determines and uses an optimum value for the phase shift or time delay value that results in an optimum uplink signal quality over the evaluated sequence of different phase shift or time delay values.