Wireless Antenna Weight Vector Classification for Multi-User Capacity
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Solution Overview
Problem
Existing wireless communication systems face challenges in maximizing transmission throughput in multi-user environments due to limitations in bandwidth and interference, particularly in high-speed downlink packet access (HSDPA) systems, where the nulling technique is difficult to apply with multiple diversity antennas far apart, leading to reduced performance and channel variability.
Innovation Solution
A wireless communication system and method that employs a multi-user diversity scheduling scheme to feed back channel state information from mobile stations to a base station, allowing for the selection and application of weights that maximize transmission capacity, enabling a nulling process across multiple diversity antennas and enhancing peak throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple diversity antennas are used to overcome channel fading, then reliability is improved, but the nulling technique cannot be effectively applied due to lack of correlation between antennas
Solution Approach 1:
The patent segments the multiple antennas into two functional groups: a first antenna for transmitting a reference signal and a second antenna for receiving the signal and performing nulling. This segmentation allows the system to maintain diversity benefits while enabling nulling operations on a subset of antennas with sufficient correlation.
Solution Approach 2:
The patent applies different processing methods to different antennas based on their local characteristics. The first antenna transmits reference signals without nulling, while the second antenna receives and applies nulling weights. This local differentiation allows the system to optimize each antenna's function according to channel conditions.
2Productivity
If bandwidth is increased to improve transmission capacity, then productivity is improved, but interference between users increases
Solution Approach 1:
The patent converts user interference into a beneficial signal by treating interfering signals as desired signals during the nulling process. The receiver uses interference signals to update weight vectors, transforming harmful interference into useful information for improving nulling performance and increasing transmission capacity.
Solution Approach 2:
The patent implements a feedback mechanism where received signals including interference are used to update weight vectors for subsequent nulling operations. This feedback loop allows the system to adapt to changing interference conditions and maintain high transmission capacity by dynamically adjusting nulling weights.
3Productivity
If beam-forming nulling technique is applied to increase bandwidth, then productivity is improved, but device complexity increases due to strict antenna spacing requirements
Solution Approach 1:
The patent segments the antenna system into a reference antenna and a processing antenna, allowing nulling to be implemented without requiring strict spacing between all antenna pairs. This segmentation relaxes the geometric constraints of conventional beam-forming while maintaining nulling effectiveness.
Solution Approach 2:
The patent changes the operational parameters of the nulling technique by using received signal strength and channel state information to dynamically adjust weight vectors, rather than relying on fixed geometric relationships. This parameter-based approach replaces spatial constraints with signal-processing-based solutions.
Data Source
AI summary
A wireless communication system, and method using multiple antennas, includes a base station that applies predetermined weight vectors to multi-user signals and transmits the multi-user signals through a plurality of transmission antennas, and a plurality of mobile stations that receive and process the multi-user signals, wherein each mobile station includes a signal reception unit that processes the multi-user signals, and a feedback signal generation unit that estimates channel characteristics, over which the multi-user signals have been transmitted, from the multi-user signals, classifies a plurality of weight vectors to be applied to the estimated channel characteristics into a plurality of sets such that vectors orthogonal to one another are classified into a single set, selects a set maximizing a transmission capacity from among the classified sets, and feeds back weight indexes of weight vectors included in the selected set and weighted channel information to the base station.