Single-Bit LVDS Envelope Tracking for MIMO RF Signal Integrity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional envelope tracking systems face challenges in maintaining RF signal integrity and power efficiency, particularly in multiple input multiple output (MIMO) systems, due to differences in propagation lengths and frequency responses between spatially separated power amplifiers, leading to signal distortions and limited bandwidth.
Innovation Solution
An envelope tracking system that uses a single-bit digital signal to encode an analog envelope tracking control signal, which is transmitted in low-voltage differential signaling (LVDS) format from a transceiver to an envelope tracker, allowing for higher bandwidth support up to 300 MHz and reducing interference, thereby compensating for signal delays and frequency responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If spatially separated power amplifiers are used in MIMO systems, then power efficiency can be improved through envelope tracking, but signal distortions occur due to differences in propagation lengths and frequency responses
Solution Approach 1:
The patent divides the envelope tracking control into multiple independent channels, with each power amplifier receiving its own dedicated envelope tracking control signal. This segmentation allows each amplifier to be optimized independently for power efficiency while maintaining signal integrity through individualized control, resolving the contradiction between power savings and signal quality in MIMO systems
Solution Approach 2:
The patent applies different envelope tracking control parameters to different spatial channels based on their specific propagation characteristics and frequency responses. By tailoring the envelope tracking behavior locally to each channel's requirements, the system achieves both power efficiency improvements and maintains signal integrity despite spatial separation
2Device complexity
If analog envelope tracking control signals are used, then system complexity is reduced, but bandwidth is limited and interference increases
Solution Approach 1:
The patent replaces the traditional analog envelope tracking control signal with a digital representation. By converting the continuous analog control signal into discrete digital values, the system achieves higher bandwidth capability and reduced interference while maintaining manageable complexity through standard digital signal processing techniques
Solution Approach 2:
The patent changes the fundamental parameter of the envelope tracking control signal from analog voltage to digital representation. This parameter change enables the system to support higher bandwidths up to 300 MHz and reduces signal interference, while the digital nature allows for efficient processing that keeps system complexity acceptable
3Use of energy by moving object
If envelope tracking is implemented to reduce power consumption, then battery life improves, but RF signal integrity may be compromised
Solution Approach 1:
The patent implements feedback mechanisms that continuously monitor the RF signal characteristics and adjust the envelope tracking control in real-time. This feedback ensures that power consumption is optimized while maintaining RF signal integrity by making dynamic adjustments based on actual signal conditions rather than using fixed envelope tracking parameters
Data Source
AI summary
Embodiments described herein relate to an envelope tracking system that uses a single-bit digital signal to encode an analog envelope tracking control signal, or envelope tracking signal for brevity. In certain embodiments, the envelope tracking system can estimate or measure the amplitude of the baseband signal. The envelope tracking system can further estimate the amplitude of the envelope of the RF signal. The system can convert the amplitude of the envelope signal to a single-bit digital signal, typically at a higher, oversample rate. The single-bit digital signal can be transmitted in, for example, a low-voltage differential signaling (LVDS) format, from a transceiver to an envelope tracker. An analog-to-digital converter (ADC or A/D) can convert the single-bit digital signal back to an analog envelope signal. Moreover, a driver can increase the power of the A/D output envelope signal to produce an envelope-tracking supply voltage for a power amplifier.