Virtual MIMO Beamforming for Coordinated Multipoint Wireless Networks
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Solution Overview
Problem
Current wireless communication technologies face challenges in improving spectral efficiency, especially in 3GPP networks, due to the limited number of antennas in most wireless devices, which restricts the application of interference alignment techniques and iterative beamforming methods.
Innovation Solution
The proposal involves configuring a cluster of wireless devices with single antennas to operate as a virtual device, allowing them to determine beamforming weights independently for coordinated multipoint communication, forming a virtual MIMO array, and iteratively updating these weights to optimize Signal to Interference and Noise Ratios (SINRs, without requiring channel information from other devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If interference alignment techniques and iterative beamforming methods are applied, then spectral efficiency is improved, but the number of antennas required increases device complexity
Solution Approach 1:
The patent merges multiple single-antenna wireless devices into a virtual MIMO device, combining their antenna resources to achieve multi-antenna beamforming capabilities. This allows the system to implement interference alignment and iterative beamforming techniques without requiring individual devices to have multiple antennas, thus improving spectral efficiency while maintaining simple device architecture.
Solution Approach 2:
The patent introduces a network node as an intermediary that coordinates the virtual MIMO device formation and manages the beamforming weight calculations. The network node receives channel state information from multiple wireless devices, computes the optimal beamforming weights, and distributes them back to the devices, enabling complex beamforming operations without increasing device complexity.
2Productivity
If virtual MIMO devices are formed by clustering wireless devices, then beamforming capabilities are improved, but communication overhead between devices increases
Solution Approach 1:
The patent extracts the complex beamforming weight calculation function from the wireless devices and relocates it to the network node. The wireless devices only need to exchange minimal channel state information with the network node, significantly reducing the communication overhead between devices while still achieving advanced beamforming capabilities through the network node's centralized computation.
3Measurement precision
If iterative beamforming is implemented, then SINR is optimized, but computational complexity increases
Solution Approach 1:
The network node acts as an intermediary that performs the computationally intensive iterative beamforming calculations. The network node receives channel state information from wireless devices, executes the iterative optimization algorithm to compute optimal beamforming weights, and distributes the results back to the devices. This approach achieves high SINR optimization while keeping the computational burden on the network infrastructure rather than on individual power-constrained wireless devices.
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AI summary
In particular embodiments, a method for determining a beamforming weight for coordinated multipoint communication with a first network node is performed by a wireless device in a cluster set of wireless devices configured to operate as a virtual device. The method includes receiving from a first network node, via a first channel, a first network RS coded with a first network beamforming weight associated with the cluster set. A second network RS is received from a second network node via the first channel. A device beamforming weight is calculated based on the first network RS received from the first network node and the second network RS received from the second network node. The calculation may be performed during a first iteration and may be independent of any channel information from any other wireless device in the cluster set of the wireless devices operating as a virtual device. The calculation of the first iteration may also be independent of any channel information associated with a second channel between the other wireless devices of the cluster set and the first network node. A first device RS coded with the device beamforming weight is sent to the first network node via the first channel.