Adaptable Mixer Topology for LTE Harmonic Rejection Linearity
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Solution Overview
Problem
Current wireless communication systems face challenges in achieving high linearity in transmit signal paths, particularly for LTE standards, due to non-linear local oscillator (LO) and mixer combinations, which result in spurious emissions and non-compliance with stringent specifications, while also needing to maintain performance in legacy modes like 2G/3G.
Innovation Solution
An adaptable mixer device operable with a multi-phase local oscillator, capable of switching between modes, including a highly linear harmonic rejection mixing (HRM) mode for 4G or LTE, by selectively activating specific mixer units and LO phases, ensuring good linearity in HRM mode without affecting legacy mode operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a non-linear local oscillator and mixer combination is used, then the device can operate in legacy modes (2G/3G), but spurious emissions increase and linearity deteriorates for LTE operation
Solution Approach 1:
The mixer is divided into multiple independent mixer units (first set and second set) that can be selectively activated. The first set of mixer units is configured for legacy mode operation while the second set is configured for LTE mode operation with improved linearity. This segmentation allows the system to use only the necessary mixer units for each operating mode, reducing spurious emissions in LTE mode while maintaining compatibility with legacy modes.
Solution Approach 2:
The system dynamically switches between different mixer unit sets and local oscillator configurations based on the operating mode. A mode selection mechanism activates either the first set of mixer units for legacy modes or the second set for LTE modes, allowing the device to adapt its linearity characteristics and LO phase configurations to meet the specific requirements of each mode without compromising overall versatility.
2Manufacturing precision
If mixer units are selectively activated for HRM mode, then linearity improves for 4G/LTE, but device complexity increases
Solution Approach 1:
The mixer units are designed with universal functionality to operate in both legacy and LTE modes. The same basic mixer unit structure can be activated in different configurations depending on the mode, reducing the need for completely separate hardware paths. This multi-functionality approach improves linearity for HRM mode while minimizing the increase in device complexity by reusing common components across modes.
3Productivity
If multiple mixer units are operated simultaneously, then productivity increases for multi-mode operation, but power consumption increases
Solution Approach 1:
The system employs periodic switching between different mixer unit sets based on the required operating mode. Instead of continuously operating all mixer units, the system activates only the necessary set (first set for legacy modes, second set for LTE modes) during each operating period. This periodic activation maintains multi-mode operation capability while significantly reducing average power consumption by keeping unused mixer units in a low-power state.
Data Source
AI summary
An adaptable mixer device is operable in a first mode and a second mode and includes a first set of mixer units operable in the first mode and a second set of mixer units operable in the second mode. The second set of mixer units includes at least one mixer unit that is common to both the first set of mixer units and the second set of mixer units. The second set of mixer units also includes a plurality of mixer units that are not in the first set of mixer units. Similarly, the first set of mixer units including a plurality of mixer units that are not in the second set of mixer units.