Transmit Diversity Using Base Station Channel Estimation
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Solution Overview
Problem
Existing wireless communication systems face challenges in providing effective transmit diversity in OFDM systems, particularly due to complexity in terminal implementation and bandwidth wastage, with existing Tx diversity schemes being complicated and requiring additional hand-shaking or calibration processes.
Innovation Solution
A closed-loop Tx diversity apparatus and method using a first Tx node with one or two antennas and a second Tx node with more than two antennas, employing a channel estimator and CSI estimator to determine signal transmission methods based on channel estimation values and phase compensation requirements, thereby simplifying the process and reducing bandwidth waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing Tx diversity schemes are used in OFDM systems, then transmit diversity can be provided, but terminal implementation complexity increases and bandwidth is wasted
Solution Approach 1:
The patent extracts the channel estimation and CSI calculation functions from the terminal and places them in the base station. The terminal only needs to receive signals from multiple antennas and forward them, while the base station performs the complex channel estimation and determines the transmission method. This extraction significantly reduces terminal complexity while maintaining transmit diversity functionality.
Solution Approach 2:
The patent introduces a base station as an intermediary that performs the complex processing tasks. The base station receives signals from multiple terminal antennas, estimates channels, calculates CSI, and determines the optimal transmission method. This intermediary approach allows the terminal to remain simple while still achieving advanced transmit diversity through base station coordination.
2Reliability
If existing Tx diversity schemes are used in OFDM systems, then transmit diversity can be provided, but additional hand-shaking or calibration processes are required causing bandwidth wastage
Solution Approach 1:
The patent performs channel estimation and CSI calculation as preliminary actions during the signal reception process. The base station continuously estimates channels and calculates CSI based on received signals, so when transmission needs to be optimized, the necessary information is already available. This eliminates the need for separate hand-shaking or calibration phases, preventing bandwidth wastage.
Solution Approach 2:
The patent makes channel estimation and CSI calculation continuous processes that occur throughout signal reception. Rather than performing these operations intermittently during hand-shaking phases, the base station continuously processes received signals to maintain up-to-date channel information, enabling immediate optimization of transmission without additional time loss.
Data Source
AI summary
In an apparatus and method for providing transmit (Tx) diversity in a multi-antenna wireless communication system, Tx diversity is provided by estimating a channel to each antenna using a signal received from the antenna, estimating channel state information (CSI) from the first Tx node to each antenna using the estimated channel, and determining a signal to be transmitted to the antennas in different methods according to whether phase compensation is required for information to be transmitted using the estimated channel and the CSI.