MIMO Spatial Stream Power Allocation via Cyclic Shifting
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Solution Overview
Problem
In MIMO wireless communication systems, equal power allocation among spatial streams does not always optimize performance, as it fails to effectively utilize power in stronger beamforming modes to enhance weaker ones, leading to suboptimal system performance.
Innovation Solution
The system unequally allocates power to spatial streams by modifying the beamforming weight vectors and cyclically shifting the mapping of streams to eigenmodes of the wireless channel, limiting power redistribution from stronger to weaker modes and ensuring consistent receive SNR across streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If equal power allocation is applied among spatial streams, then implementation simplicity is maintained, but system performance is suboptimal
Solution Approach 1:
The patent applies local quality by allocating different power levels to different spatial streams based on their individual channel conditions. Specifically, spatial streams are grouped into strong and weak groups, and power is redistributed from strong to weak streams to optimize overall system performance while maintaining implementation feasibility through structured power allocation matrices.
2Reliability
If power is redistributed from stronger beamforming modes to weaker ones, then system performance is improved, but power allocation complexity increases
Solution Approach 1:
The patent segments spatial streams into distinct groups (strong and weak beamforming modes) based on channel conditions. This segmentation enables targeted power redistribution strategies where power is systematically allocated from strong to weak groups using structured power allocation matrices, making the complex power optimization problem more manageable and implementable.
Solution Approach 2:
The patent changes power allocation parameters dynamically based on channel conditions. By adjusting power distribution ratios between strong and weak spatial streams according to measured channel state information, the system optimizes performance while maintaining controlled complexity through parameter-based adaptation rather than complex structural changes.
3Reliability
If cyclic shifting of stream mapping is implemented, then frame error rate is reduced, but processing complexity increases
Solution Approach 1:
The patent implements cyclic shifting of spatial stream to eigenmode mapping periodically or adaptively based on channel conditions. This periodic remapping diversifies the mapping between streams and modes across different time instances, reducing the impact of deep fades on specific stream-mode pairs and thereby reducing frame error rates while adding manageable processing complexity through systematic permutation operations.
Data Source
AI summary
Multiple-input multiple-output (MIMO) wireless communication techniques are provided that involve mapping multiple spatial streams to corresponding modes of a wireless channel between a plurality of antennas of a first wireless communication device and a plurality of antennas of a second wireless communication device so as to allocate or distribute power unequally to the plurality of modes. In addition, techniques are provided herein to cyclically shift a mapping of spatial streams to modes of the channel.