Multi-band OFDM Antenna Selection via Sub-band SNR
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Solution Overview
Problem
Multi-band OFDM systems with multiple antennas incur increased costs due to the necessity of multiple RF chains, which hinders the widespread adoption of performance-enhancing multiple antenna techniques.
Innovation Solution
An energy-based antenna selection technique that reduces the number of RF chains by selecting antennas based on the largest SNR averaged over all carriers in each sub-band, allowing for efficient antenna selection in frequency-selective channels, particularly in space-time coded OFDM systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple antennas are used for spatial diversity, then system performance is improved, but the number of RF chains and cost increase
Solution Approach 1:
The patent divides the frequency spectrum into multiple sub-bands and applies antenna selection independently to each sub-band. This segmentation allows the system to exploit frequency-selective fading characteristics where different sub-bands experience different channel conditions, enabling performance improvement with fewer RF chains by selecting the best antenna for each sub-band based on channel quality indicators
Solution Approach 2:
The patent changes the operating parameter by selecting different antennas for different sub-bands based on channel conditions. Instead of using all antennas across all frequencies, the system dynamically selects the optimal antenna for each sub-band, thereby reducing the effective number of RF chains needed while maintaining performance through adaptive parameter adjustment
2Reliability
If multiple RF chains are implemented for multiple antenna techniques, then spatial diversity is achieved, but system cost increases
Solution Approach 1:
The patent applies partial action by implementing antenna selection only for the best-performing sub-bands or using a reduced number of RF chains compared to the total number of antennas. This allows the system to achieve spatial diversity benefits in the most critical frequency regions without deploying full multiple RF chain architectures across all antennas, thereby reducing overall system cost
Data Source
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AI summary
The present invention provides a system (300-400), apparatus (300-400), and method for an energy-based antenna selection technique in which the antenna that observes the largest SNR averaged over all carriers per sub-band (405) is selected for space-time coded MB-OFDM systems. Due to the frequency-selective nature of the system, different sub-band may have different channel gaining effect from the multi-path channels. We can perform energy-based antenna selection per sub-band, and the simulation results show that the proposed technique works not only for MB-OFDM UWB channels with shadowing, but also for the same channel without shadowing.