Adaptive Cyclic Prefix Length for MIMO Beamforming Interference
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Solution Overview
Problem
In MIMO-SC-FDE wireless communication systems, FIR-type transmission beamforming extends the equivalent channel impulse response (CIR) length, leading to inter-block interference and degradation of communication quality when the CIR length exceeds the cyclic prefix (CP) length.
Innovation Solution
A wireless communication system that adjusts the CP length based on the extended CIR length by calculating the effective CIR length between antennas and setting the maximum CIR length as the CP length, ensuring inter-block interference is mitigated through adaptive CP length adjustment in either the transmission or reception station device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If FIR-type transmission beamforming processing is performed in a time domain, then inter-antenna interference is removed, but the equivalent CIR length is extended causing inter-block interference when it exceeds the CP length
Solution Approach 1:
The patent applies dynamics by making the CP length adjustable rather than fixed. The base station dynamically adjusts the CP length based on the effective CIR length calculated from channel state information, allowing the system to adapt to varying channel conditions and prevent inter-block interference while maintaining the benefits of FIR-type beamforming.
Solution Approach 2:
The patent changes the parameter of CP length based on the effective CIR length. By calculating the effective CIR length from channel state information and adjusting the CP length accordingly (setting it to be greater than or equal to the effective CIR length), the system prevents inter-block interference while maintaining transmission performance.
2Ease of manufacture
If a fixed CP length is used in block transmission, then implementation is simple, but inter-block interference occurs when the equivalent CIR length exceeds the CP length
Solution Approach 1:
The system transitions from a static fixed CP length to a dynamic adjustable CP length. The base station calculates the effective CIR length based on channel state information and adjusts the CP length dynamically to match the channel conditions, ensuring reliable communication while maintaining reasonable implementation complexity through automated adjustment.
Solution Approach 2:
The patent implements feedback by using channel state information to calculate the effective CIR length and adjust the CP length accordingly. The base station receives channel state information from user equipment, calculates the required CP length, and applies the appropriate setting, creating a closed-loop system that adapts to changing channel conditions.
Data Source
AI summary
A transmission station device includes a training signal generation unit, a CP addition unit, and a transmission beamforming unit that performs transmission beamforming processing in a time domain using a transmission weight for removing inter-antenna interference. A reception station device includes a CP removal unit, a channel estimation unit, and an equalization unit that performs equalization processing for removing inter-symbol interference in a frequency domain using a reception weight. Either of the transmission station device or the reception station device is provided with a weight calculation unit that calculates the transmission weight and the reception weight based on the channel response, an effective CIR length calculation unit that calculates an effective CIR length between antennas, and a CP length setting unit that sets, to the CP length, a maximum CIR length among the CIR lengths of respective items of the reception weight.