Relay Station Delay Diversity Using FIR Filters
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Solution Overview
Problem
In wireless communications, particularly in 5G systems, achieving sufficient diversity effect is challenging due to high correlation between radio signal propagation characteristics among multiple antennas in relay stations, which limits the effectiveness of non-regenerative relay for terminal stations with one antenna.
Innovation Solution
A relay station with multiple antennas employs finite impulse response (FIR) filters to assign different delays to baseband signals, implementing delay diversity by converting and transmitting signals from each antenna with unique delay amounts, thereby enhancing diversity gain at the reception station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-regenerative relay is used with multiple antennas in a relay station, then the relay communication functionality is provided, but the diversity effect at the reception station is insufficient due to high correlation between radio signal propagation characteristics among multiple antennas
Solution Approach 1:
The patent applies parameter changes by modifying the delay parameter of baseband signals through FIR filters. Each antenna's baseband signal is assigned a different delay amount, which changes the temporal parameter of the transmitted signals. This parameter modification creates artificial delay diversity that compensates for the high correlation in propagation characteristics, enabling the reception station to obtain sufficient diversity effect even when using a single antenna.
2Productivity
If multiple antennas are used in the relay station, then signal transmission capability is improved, but the complexity of signal processing increases due to need for different delay assignments
Solution Approach 1:
The patent applies segmentation by dividing the signal processing into independent paths for each antenna. Each antenna's baseband signal is processed separately through its own FIR filter with a specific delay assignment. This segmented processing approach manages the complexity by treating each antenna independently rather than processing all antennas together, making the system more manageable while still achieving the desired diversity effect.
Solution Approach 2:
The patent applies universality by using the same type of processing structure (FIR filter with delay assignment) for all antennas. Each antenna follows the same processing paradigm, which provides a universal solution that can be applied regardless of the number of antennas. This multi-functional approach allows the system to handle multiple antennas with a consistent processing framework, reducing overall system complexity.
Data Source
AI summary
A relay station comprises antennas, wireless devices corresponding to the antennas, and a controller to control an operation of the wireless devices. Each of the wireless devices includes a receiver to convert the first radio signal received by a corresponding antenna into a baseband signal, an FIR filter to assign a delay to the baseband signal; and a transmitter to convert a signal output from the FIR filter into a second radio signal transmitted from the corresponding antenna to the reception station. The controller sets a different delay amount in the FIR filter in each of the wireless devices so that the FIR filter assigns a delay, which is different from among the antennas, to the baseband signal input from the receiver in each of the wireless devices.