Dynamic LNA Disconnection for Filterless MIMO Interference Management
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Solution Overview
Problem
In wireless communication systems, the removal of surface acoustic wave (SAW) filters from MIMO receive chains to reduce cost and complexity leads to increased internal interference, potentially damaging components like the low noise amplifier (LNA) and degrading performance, especially in FDD and TDD systems where concurrent transmission and reception occur.
Innovation Solution
A method where the LNA is selectively connected or disconnected from the receive chain based on the internal interference level, determined by the transmit power, to protect the LNA and adjust operations to account for the absence of a SAW filter, including modifying baseband processor operations and channel state information reporting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If SAW filters are removed from MIMO receive chains, then cost and complexity are reduced, but internal interference increases and component reliability deteriorates
Solution Approach 1:
The patent implements dynamic switching between filtered and unfiltered receive paths based on interference conditions. The system monitors interference levels and selectively activates the SAW filter for specific receive chains only when needed, transitioning from a static always-on filter architecture to a dynamic conditional architecture that reduces overall complexity while maintaining reliability when required
Solution Approach 2:
The patent applies filtering selectively to specific receive chains rather than uniformly across all MIMO receive paths. By identifying which receive chains experience harmful interference and applying SAW filters only to those specific chains, the system achieves local optimization that reduces overall device complexity and cost while maintaining component reliability only where necessary
2Ease of manufacture
If SAW filters are removed from MIMO receive chains, then manufacturing cost is reduced, but internal interference increases and may damage components
Solution Approach 1:
The patent extracts the SAW filter from the standard MIMO receive chain architecture and places it in a conditional, selective position. Instead of having filters permanently integrated into all receive paths, the system extracts the filtering function and applies it only to specific receive chains when interference conditions warrant it, reducing manufacturing cost while protecting against harmful interference through selective deployment
Solution Approach 2:
The patent introduces an interference monitoring and control mechanism that acts as an intermediary between the transmit and receive chains. This intermediary monitors interference levels and selectively activates filtering only when harmful interference is detected, mediating between the cost-saving unfiltered architecture and the protection-needed filtered architecture
3Reliability
If LNA is continuously connected to protect against interference, then component protection is improved, but performance degrades due to increased insertion loss
Solution Approach 1:
The patent implements periodic monitoring of interference levels and selective activation of protective measures. Instead of continuously connecting protective elements that would cause constant insertion loss, the system periodically checks for harmful interference and only activates protection (such as disconnecting the LNA or activating filters) when interference is detected, achieving component protection while minimizing energy loss during normal operation
4Device complexity
If internal interference is allowed to increase without filtering, then device complexity is reduced, but system productivity decreases due to performance degradation
Solution Approach 1:
The patent changes the operational parameters of the receive chain dynamically based on interference conditions. Instead of maintaining a fixed complex filtered architecture, the system adjusts parameters such as filter activation status, receive chain connectivity, and processing modes based on real-time interference measurements, achieving simplified operation during good conditions while maintaining performance during poor conditions
Data Source
AI summary
Some techniques and apparatuses described herein protect components of a user equipment (UE), such as a low noise amplifier (LNA), from internal interference. For example, the LNA may be disconnected from a receive chain during periods of high internal interference, and may be reconnected to the receive chain during periods of low internal interference. Furthermore, some techniques and apparatuses described herein improve performance by adjusting operations of the UE to account for and/or offset increased internal interference due to a receive chain that does not include a surface acoustic wave (SAW) filter to remove unwanted radio frequency signals. For example, one or more operations of a baseband processor may be modified to account for the increased internal interference. Additionally, or alternatively, reporting of channel state information may be modified to account for increased internal interference of the UE. Additional details are described herein.