Distributed Antenna Scheduling for Multi-User Transmission
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Solution Overview
Problem
Conventional distributed antenna systems lack an effective method for selecting an optimal combination of wireless terminals and distributed antennas for multi-user transmission in multi-BSS or single BSS wireless environments, which hinders throughput improvement.
Innovation Solution
A wireless base station using distributed antennas measures reception power (RSSI) from each wireless terminal at each antenna, selects combinations based on similar or descending RSSI values, and controls transmission power to minimize interference and channel correlation, thereby optimizing the combination of wireless terminals and antennas for multi-user transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If distributed antennas are used for multi-user transmission, then reception power is improved, but interference with other BSSs increases
Solution Approach 1:
The patent applies local quality by selecting specific distributed antennas based on their local reception power characteristics for each wireless terminal. The scheduling unit measures reception power from each terminal at each antenna and selects combinations where RSSIs are similar, ensuring each antenna operates in its optimal local condition while minimizing overall interference to other BSSs.
Solution Approach 2:
The patent changes the parameter of transmission power dynamically based on measured reception power levels. The transmission power control unit sets minimum transmission power corresponding to the RSSI of selected antennas, adjusting power levels to maintain reliable reception while reducing interference generated by excessive power transmission.
2Reliability
If transmission power is increased to improve reception power, then reliability improves, but interference with other BSSs increases
Solution Approach 1:
The patent dynamically adjusts transmission power as a variable parameter based on measured reception power levels. The transmission power control unit sets minimum transmission power corresponding to the RSSI of selected antennas, ensuring power is increased only when necessary to maintain reliable reception, thereby avoiding excessive interference to other BSSs.
Solution Approach 2:
The patent implements feedback by measuring reception power from each wireless terminal at each distributed antenna and using this information to control transmission power. The scheduling unit and transmission power control unit use the measured RSSI values to make informed decisions about power allocation, creating a closed-loop system that balances reliability and interference.
3Reliability
If antenna combinations are selected based on highest RSSI, then reception power is maximized, but channel correlation increases
Solution Approach 1:
The patent introduces asymmetry in antenna selection by not simply choosing the single highest RSSI antenna, but rather selecting combinations of antennas where RSSIs are similar across multiple antennas. This asymmetric approach to selection criteria balances reception power maximization with channel correlation reduction, improving overall system stability.
Solution Approach 2:
The patent inverts the conventional approach by not selecting antennas based solely on highest individual RSSI values, but rather selecting combinations where RSSIs are approximately equal. This inversion of the selection criterion simultaneously achieves reception power maximization and channel correlation minimization.
Data Source
AI summary
Provided is a wireless base station which uses distributed antennas and selects a combination of a plurality of wireless terminals and the distributed antennas of a wireless base station that performs multi-user transmission with respect to the plurality of wireless terminals in a multi-BSS wireless environment. The wireless base station includes: a scheduling unit that measures reception power (RSSI) from each wireless terminal at each of the distributed antennas and selects a combination of a plurality of wireless terminals and a plurality of antennas having approximately the same RSSIs in descending order for respective wireless terminals; and a transmission power control unit that sets minimum transmission power corresponding to the RSSI of the antenna when multi-user transmission is performed between the plurality of wireless terminals and the plurality of antennas combined by the scheduling unit.