MIMO Mobile Station Base Station Selection by Channel Capacity
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Solution Overview
Problem
In MIMO communication, selecting a base station apparatus based on reception SIR or traffic alone does not reliably improve reception quality and throughput, as signals from different paths can be mutually destructive, limiting cell coverage.
Innovation Solution
A mobile station apparatus selects a communicating party by receiving signals from multiple candidates, acquiring channel capacity indicating reception quality or number of paths, and choosing the candidate with the highest channel capacity for improved throughput and coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If base station apparatus is selected based on reception SIR or traffic amount, then switching speed is improved, but reception quality and throughput are not reliably improved due to signal destruction from multiple paths
Solution Approach 1:
The patent changes the selection parameter from simple reception SIR or traffic amount to channel capacity that incorporates path correlation information. By using singular value decomposition to calculate channel capacity, the system selects base station apparatus based on a parameter that reflects the actual MIMO communication capability, resolving the contradiction between fast switching and reliable reception quality improvement.
2Productivity
If base station apparatus switching is performed in slot cycle, then throughput improvement is achieved in handover area, but cell coverage enlargement is limited due to signal destruction
Solution Approach 1:
The patent introduces channel capacity as a new selection parameter that accounts for path correlation, enabling reliable throughput improvement. This allows cell coverage to be enlarged because the selection is based on actual MIMO capability rather than simple signal strength, ensuring that throughput improvement is achieved without the limitation of signal destruction from multiple paths.
3Quantity of substance
If signals from multiple paths are received, then more communication paths are available, but reception quality deteriorates due to mutual destruction of signals
Solution Approach 1:
Instead of selecting base station apparatus with the strongest individual signal paths, the patent inverts the approach by selecting based on channel capacity that reflects the overall MIMO communication capability. The singular value decomposition identifies the effective number of independent paths, and the apparatus with the highest channel capacity (indicating better path independence) is selected, thus converting the harmful effect of multiple paths into a useful selection criterion.
Data Source
AI summary
It is possible to surely improve the throughput in a handover area in the MIMO communication and increase the cell coverage. Channel estimation units (104-1, 104-2) perform a channel estimation by using a common pilot signal transmitted from each base station device and acquire a channel matrix for each cell. Singular value decomposition processing units (105-1, 105-2) perform singular value decomposition processing by using a channel matrix corresponding to each cell. Channel capacity calculation units (106-1, 106-2) compare a singular value for each path to a threshold value and calculate the number of singular values above a predetermined threshold value as the channel capacity. A cell selection unit (107) compares the channel capacity sizes and selects a base station device corresponding to a greater channel capacity.