LNA Gain-State Scanning for Faster TDD Initial Acquisition
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Solution Overview
Problem
In Time Division Duplex (TDD) communication systems, the initial acquisition of signals is complicated due to uncertainty in uplink/downlink timelines, making it challenging to set the gain of a Low Noise Amplifier (LNA) accurately, as it cannot be run in a continuous mode like in Frequency Division Duplex systems, leading to inefficiencies and longer acquisition times.
Innovation Solution
A method involving running a plurality of predetermined amplifier gain states in a predefined order during initial acquisition in a TDD system, with a searcher determining acquisition by scanning across these states until a known signal is detected, potentially using a sparse subset of states and multiple antennas to speed up the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous mode AGC/LNA algorithm is used, then gain control is accurate and stable, but it cannot be applied in TDD systems due to UL/DL timeline uncertainty
Solution Approach 1:
The patent applies dynamics by making the LNA gain state changeable over time through sequential scanning. The system dynamically transitions between different LNA gain states (e.g., from highest gain to lowest gain) during the initial acquisition phase, allowing the receiver to adapt to unknown signal conditions in TDD systems where continuous monitoring is not possible.
Solution Approach 2:
The patent implements preliminary action by pre-defining a sequence of LNA gain states that will be scanned during initial acquisition. The system prepares and executes a predetermined scanning pattern across multiple gain states before actual data reception begins, enabling the receiver to establish appropriate gain settings in advance for TDD operation.
2Device complexity
If LNA gain state is fixed, then device complexity is reduced, but initial acquisition time increases due to need to scan multiple states
Solution Approach 1:
The patent applies segmentation by dividing the initial acquisition process into discrete stages corresponding to different LNA gain states. Instead of treating gain adjustment as a continuous or monolithic process, the system segments the acquisition into sequential steps where each gain state is tested independently, allowing systematic search through the gain space.
Solution Approach 2:
The patent implements periodic action by scanning through LNA gain states in a repeated, systematic sequence. The system periodically cycles through predefined gain states (e.g., highest, medium, lowest) during initial acquisition, using this periodic scanning pattern to efficiently identify the appropriate gain setting without requiring complex real-time adjustment mechanisms.
3Measurement precision
If all amplifier gain states are scanned, then complete coverage is achieved, but acquisition process becomes slower
Solution Approach 1:
The patent applies local quality by focusing the gain state scanning on specific, locally relevant states rather than uniformly examining all possible states. The system identifies and prioritizes scanning certain gain states (such as highest, medium, and lowest) that are most likely to contain the optimal setting, allocating more investigative resources to these critical local regions of the gain space.
Solution Approach 2:
The patent implements skipping by selectively bypassing certain LNA gain states during the scanning process. Instead of methodically testing every single gain state, the system skips over states that are less likely to be optimal, rushing through the acquisition process by jumping between key gain states and thereby reducing overall acquisition time while maintaining sufficient coverage.
Data Source
AI summary
A plurality of predetermined amplifier gain states for a low noise amplifier (LNA) are run during initial acquisition in a time division duplex (TDD) system. Acquisition of a received signal is determined based on searching across the plurality of predetermined amplifier gain states. Forcing the amplifier gain into a set of predetermined gain states affords quicker resolution of initial acquisition for setting the gain of the LNA, which in TDD systems is complicated due to an uncertain uplink/downlink timeline that precludes continuous operation of a gain setting algorithm run in the LNA.