Multi-Antenna Signal Equalization for Dense Wireless Terminal Reception
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Solution Overview
Problem
Existing wireless communication systems struggle to accurately receive signals simultaneously transmitted from a large number of wireless terminals due to limitations in signal multiplexing and antenna capabilities.
Innovation Solution
A wireless communication system employing a mobile relay station with multiple antennas that receives and processes the same radio signals multiple times, using MIMO equalization and demodulation techniques to separate and demodulate signals from multiple terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple antennas are used to receive signals from multiple terminals, then signal multiplexing capability is improved, but the degree of freedom is limited by the number of antennas
Solution Approach 1:
The patent transitions from spatial multiplexing (using multiple antennas) to temporal multiplexing (using multiple reception timings). By storing signals received at different times and processing them together, the system achieves signal separation capability that exceeds the number of physical antennas, effectively adding a time dimension to the reception process.
Solution Approach 2:
The patent performs preliminary storage of received signals at multiple timings before actual demodulation. The signal storage unit preserves signals from different time instances, allowing subsequent equalization processing to utilize temporal diversity. This preliminary action enables the system to accumulate sufficient signal samples for accurate equalization without requiring additional antennas.
2Reliability
If signals are transmitted multiple times at different timings, then signal reception reliability is improved, but signal collision and interference increase
Solution Approach 1:
The patent employs equalization processing that utilizes feedback from previously received signals to cancel interference in current signals. By processing signals in temporal sequence and using information from earlier receptions to mitigate interference in later receptions, the system converts interference into useful information for improving overall reception reliability.
Solution Approach 2:
The patent transforms signal collisions and interference, which are normally harmful, into beneficial temporal diversity. By storing and jointly processing signals that collided at different timings, the equalization unit extracts useful information from what would otherwise be interference, converting the harmful effect of signal collision into an advantage for signal separation.
3Device complexity
If one antenna is used at base station, then device complexity is reduced, but signal separation accuracy deteriorates
Solution Approach 1:
The patent compensates for having a single antenna by introducing the time dimension. Instead of relying solely on spatial diversity from multiple antennas, the system captures signals at multiple time instances and processes them together, achieving signal separation accuracy comparable to or exceeding that of multi-antenna systems while maintaining simple hardware configuration.
Data Source
AI summary
Each transmitting apparatus transmits the same radio signals a plurality of times. A communication apparatus includes a plurality of antennas, a signal storage unit, a reading unit, an equalization unit, and a demodulation unit. The plurality of antennas receives radio signals transmitted from a plurality of the transmitting apparatuses. The signal storage unit stores reception signals received by each of the plurality of antennas. The reading unit reads, from the signal storage unit, reception signals including radio signals transmitted from a demodulation processing target transmitting apparatus, the reception signals being received by each of the plurality of antennas at different times. The equalization unit equalizes the plurality of reception signals read by the reading unit. The demodulation unit demodulates the equalized reception signals.