Interleaved ADC Power Management for Wireless LAN Synchronization
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Solution Overview
Problem
High power consumption in large bandwidth wireless LAN systems, particularly due to idle listening mode where high-speed ADCs are constantly active, leading to significant battery drain and inefficiency, especially in mmWave frequencies where communication links are fragile and require frequent beamforming training.
Innovation Solution
Implementing a two-part preamble transmission where the first part is sent at a reduced bandwidth and the second part at full bandwidth, using an interleaved ADC with multiple sub-ADCs that are turned on only when necessary, reducing power consumption during idle listening and synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-speed ADCs are continuously active during idle listening mode to detect packets in large bandwidth systems, then packet detection capability is maintained, but power consumption increases significantly
Solution Approach 1:
The patent segments the ADC operation into two distinct modes: a low-power detection mode using a first subset of sub-ADCs during idle listening, and a full-power reception mode using all sub-ADCs during active packet reception. This segmentation allows the system to maintain packet detection capability while significantly reducing power consumption during idle periods.
Solution Approach 2:
The patent implements dynamic switching between different ADC operational states based on channel activity detection. The system transitions from a static full-power mode to a dynamic mode where the ADC bandwidth and power consumption are adaptively adjusted according to whether packets are being transmitted, optimizing the trade-off between detection reliability and energy efficiency.
2Measurement precision
If the entire preamble is transmitted at full bandwidth, then synchronization accuracy is maximized, but power consumption during transmission and reception increases
Solution Approach 1:
The patent divides the preamble into two parts: a first preamble part transmitted at reduced bandwidth for initial synchronization and detection, and a second preamble part transmitted at full bandwidth for refined synchronization. This segmentation enables the receiver to achieve adequate synchronization accuracy while consuming less power during the detection phase, before committing to full-power reception.
Solution Approach 2:
The patent performs preliminary synchronization using a reduced-bandwidth first preamble part before committing to full-bandwidth operation. This preliminary action allows the receiver to determine whether a packet is present and perform coarse synchronization at lower power, avoiding the need to continuously operate at full power for synchronization.
3Use of energy by moving object
If reduced bandwidth is used for the first preamble part, then power consumption is reduced during idle listening, but synchronization time may increase
Solution Approach 1:
The patent segments the synchronization process into two stages: a fast initial synchronization stage using reduced bandwidth for the first preamble part, followed by a refinement stage using full bandwidth for the second preamble part. This segmentation reduces overall synchronization time compared to using reduced bandwidth alone, while still achieving significant power savings during the critical initial detection phase.
Solution Approach 2:
The patent performs preliminary coarse synchronization using the reduced-bandwidth first preamble part, which establishes basic timing and frequency alignment quickly. This preliminary action prepares the receiver for the subsequent full-bandwidth refinement stage, reducing the total time required compared to performing all synchronization operations at full bandwidth.
Data Source
AI summary
In a packet-based communication system, a transmitter and a receiver implement low power synchronization techniques. The transmitter transmits a packet that includes a two-part preamble. A first part of the two-part preamble is transmitted at a first reduced bandwidth that is smaller than a second bandwidth of the channel, and at least one of a second part of the two-part preamble and another portion of the packet is transmitted at the second bandwidth of the channel. The receiver includes an interleaved analog-to-digital converter (ADC) including multiple sub-ADCs. The receiver turns on a first subset of the multiple sub-ADCs during an idle listening period, and turns on a second subset of the multiple sub-ADCs upon detection of a completion of the first part of the two-part preamble, wherein the first subset of the multiple sub-ADCs is less than the second subset of the multiple sub-ADCs.