Uplink Center Frequency Alignment for Image Interference Reduction
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Solution Overview
Problem
In wireless communications, especially for Machine-type (MTC) devices with limited transmission bandwidth, IQ image interference occurs due to misalignment of center frequencies with the cell center frequency, leading to system performance degradation.
Innovation Solution
Wireless devices are configured to determine an uplink center frequency based on the center frequency of allocated resources, either aligning it with the resource center or adjusting it to the edge of the allowed frequency range to minimize image interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If MTC devices use flexible center frequency positioning to adapt to limited transmission bandwidth, then device adaptability is improved, but image interference increases and system performance degrades
Solution Approach 1:
The patent changes the center frequency parameter of the MTC device to align with the cell center frequency. This parameter adjustment ensures that the uplink transmission center frequency matches the cell center frequency, thereby preventing image interference while maintaining flexible bandwidth adaptation. The base station configures the appropriate center frequency offset value to achieve this alignment.
2Productivity
If MTC devices transmit with limited bandwidth not aligned with cell center frequency, then bandwidth efficiency is improved, but multiple image products are generated causing interference
Solution Approach 1:
The patent adjusts the center frequency parameter by configuring a specific frequency offset value that aligns the MTC device's uplink center frequency with the cell center frequency. This allows the device to maintain its limited bandwidth transmission while eliminating the misalignment that causes multiple image products. The base station determines and signals the appropriate offset value to achieve proper frequency alignment.
Data Source
AI summary
Methods and apparatuses are disclosed for reducing image interference in uplink transmission. In one embodiment, a wireless device (WD) is configured to receive an indication of a resource allocation from the network node; determine an uplink center frequency based at least in part on a center frequency of a resource allocated by the received indication of the resource allocation; and transmit uplink information according to the determined uplink center frequency.