MIMO Packet Preamble Layout for Two-Stage AGC Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless receiving devices face challenges in maintaining appropriate input levels for A/D converters during MIMO transmission, leading to saturation or quantization errors due to varying signal levels from multiple antennas, which degrades reception performance.
Innovation Solution
A wireless transmitting device that generates a wireless packet format with a short-preamble sequence for initial AGC, followed by parallel transmission of AGC preamble sequences from multiple antennas to fine-tune the input level of the A/D converter, ensuring appropriate signal adjustment and enhanced reception performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If AGC is performed using only the short-preamble sequence from a single transmit antenna, then the initial receiving level can be controlled, but the receiving levels of signals from other antennas cannot be adjusted, causing saturation or quantization errors in the A/D converter
Solution Approach 1:
The patent segments the AGC process into two distinct phases: first AGC using the short-preamble sequence from a reference antenna, and second AGC using dedicated AGC preamble sequences transmitted from all antennas. This segmentation allows each AGC phase to address specific requirements - initial gain setting followed by per-antenna level adjustment - thereby resolving the contradiction between initial control and comprehensive reliability.
Solution Approach 2:
The patent applies preliminary action by performing the first AGC using the short-preamble sequence before the actual data transmission begins. This preliminary gain control establishes a baseline that prevents saturation during initial reception, and the subsequent second AGC with multi-antenna preambles further refines the control before data transmission, ensuring reliable reception throughout.
2Productivity
If MIMO transmission is implemented with multiple antennas transmitting simultaneously, then the throughput is improved, but the variation in receiving levels from different antennas causes A/D converter saturation or quantization errors
Solution Approach 1:
The patent introduces AGC preamble sequences as intermediary signals transmitted from all MIMO antennas before data transmission. These intermediary preambles serve as mediators that allow the receiver to measure and adjust gain for each antenna's signal level independently, thereby enabling precise level control that prevents saturation and quantization errors while maintaining the high throughput benefits of MIMO transmission.
3Device complexity
If the A/D converter input dynamic range is fixed, then the device complexity is reduced, but the receiving performance degrades when signal levels exceed or fall below the acceptable range
Solution Approach 1:
The patent applies dynamics by implementing a two-stage AGC system that dynamically adjusts the receiver gain in two phases: first using the short-preamble to establish initial gain, and second using the multi-antenna AGC preambles to refine gain settings. This dynamic adjustment capability allows the fixed-range A/D converter to handle varying signal levels from multiple antennas, maintaining high reception reliability without increasing converter complexity.
Data Source
AI summary
A wireless device, method, and signal for use in communication of a wireless packet between transmitting device and a wireless receiving device via a plurality of antennas, wherein a signal generator generates wireless packet including a short-preamble sequence used for a first automatic gain control (AGC), a first long-preamble sequence, a signal field used for conveying a length of the wireless packet, an AGC preamble sequence used for a second AGC to be performed after the first AGC, a second long-preamble sequence, and a data field conveying data. The AGC preamble sequence is transmitted in parallel by the plurality of antennas.