Frequency-Agile Wireless Transmitter for Intermodulation Reduction
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Solution Overview
Problem
Wireless communication devices face issues such as receiver desensitization and spurious emissions due to intermodulation and non-linear effects, particularly when transmitting narrow band allocations within large bandwidth channels, as seen in LTE and SC-FDMA systems.
Innovation Solution
The method involves determining the range and center frequency of resource blocks for transmission, dynamically varying the bandwidth of the analog baseband portion, and modulating resource blocks at the approximate center frequency to minimize intermodulation and desensitization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If narrow band resource blocks are transmitted at edge frequencies of large bandwidth channels, then spectrum efficiency is improved, but receiver desensitization and spurious emissions occur due to intermodulation and non-linear effects
Solution Approach 1:
The patent applies dynamics by making the transmitter frequency agile - the carrier frequency is dynamically adjusted to track the center frequency of the allocated resource blocks rather than remaining fixed at the edge of the channel. This dynamic frequency adjustment prevents the transmitter from operating at frequencies that cause intermodulation products to fall within the receiver's sensitive bandwidth, thereby eliminating receiver desensitization while maintaining spectrum efficiency.
Solution Approach 2:
The patent changes the frequency parameter of the transmitter dynamically based on the allocated resource block range. By calculating the center frequency of the resource blocks and adjusting the transmitter frequency to match this center point, the system transforms the transmission from a static edge-frequency operation to a dynamic center-frequency operation, eliminating harmful intermodulation effects while preserving spectral efficiency.
2Device complexity
If fixed frequency transmission is used for resource blocks, then system complexity is reduced, but intermodulation and desensitization issues persist
Solution Approach 1:
The patent introduces dynamic frequency adjustment based on the allocated resource block range. The frequency control mechanism calculates the center frequency of the resource blocks and automatically adjusts the transmitter frequency accordingly. This dynamic approach, while adding some control complexity, ensures reliable transmission by preventing intermodulation products from falling within the receiver's sensitive bandwidth, thereby improving overall transmission reliability.
3Productivity
If large bandwidth channels are used to achieve high peak data rate, then productivity is improved, but unwanted emissions and non-linear effects increase
Solution Approach 1:
The patent applies dynamics by making the transmitter frequency agile - the carrier frequency is dynamically adjusted to track the center frequency of the allocated resource blocks rather than remaining fixed. This dynamic frequency adjustment ensures that even when large bandwidth channels are used for high peak data rates, the transmitter operates at frequencies that prevent intermodulation products from falling within the receiver's sensitive bandwidth, thereby eliminating unwanted emissions while maintaining high productivity.
Solution Approach 2:
The patent changes the frequency parameter dynamically based on the allocated resource block range. By calculating the center frequency of the resource blocks and adjusting the transmitter frequency to match this center point, the system transforms the transmission from a static operation to a dynamic one, eliminating harmful intermodulation effects while preserving the ability to achieve high peak data rates through large bandwidth utilization.
Data Source
AI summary
In accordance with some embodiments of the present disclosure, a method may include determining a range of frequencies allocated to resource blocks to be transmitted during a subsequent sub-frame slot or sounding reference symbol sub-slot. The method may also include determining an approximate center frequency of the range of frequencies. The method may additionally include modulating resource blocks of the sub-frame or sounding reference symbol sub-slot at the approximate center frequency. The method may further include transmitting the modulated resource blocks at the approximate center frequency.