Multi-Cell MIMO Precoding for Interference-Aware Network Virtualization
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Solution Overview
Problem
Existing multi-cell MIMO wireless network virtualization technologies face challenges in managing interference between service providers and cells, leading to suboptimal system performance due to limited precoding space for interference control, especially in scenarios where channel state information (CSI) exchange and transmit power updates are impractical.
Innovation Solution
A distributed coordinated downlink precoding method that balances signal leakage and precoding deviation through convex programming, allowing for interference suppression and virtualization demand satisfaction without CSI exchange or transmit power updates across cells, using a semi-closed form solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strict service separation is applied to achieve service isolation among SPs, then service isolation is improved, but resource utilization deteriorates due to limited sharing of wireless spectrum and antenna hardware
Solution Approach 1:
The patent segments the precoding space into multiple orthogonal subspaces, each allocated to a different SP. This allows multiple SPs to share the same physical resources (antenna hardware and wireless spectrum) while maintaining service isolation through orthogonal precoding matrices, thereby resolving the contradiction between service isolation and resource utilization
Solution Approach 2:
The patent moves from traditional time-frequency resource division to precoding space dimension for service isolation. By utilizing the spatial dimension through MIMO precoding, multiple SPs can coexist on the same time-frequency resources with orthogonal precoding matrices, improving resource utilization while maintaining isolation
2Productivity
If coordinated precoding is implemented across multiple cells, then system performance is improved, but computational complexity increases due to the need for global CSI sharing and signal-level coordination
Solution Approach 1:
The patent segments the coordinated precoding problem into cell-specific subproblems. Each cell independently computes its precoding matrix based on local CSI and global channel statistics, avoiding the need for global CSI sharing and complex signal-level coordination while still achieving multi-cell coordination benefits
Solution Approach 2:
Each cell autonomously determines its precoding strategy using locally available information (local CSI and broadcasted global channel statistics), eliminating the need for complex inter-cell coordination mechanisms and reducing computational complexity
3Ease of operation
If traditional precoding methods are used in virtualized networks, then implementation simplicity is maintained, but interference control capability deteriorates due to limited precoding space
Solution Approach 1:
The patent segments the precoding space into orthogonal subspaces for different SPs, enabling independent interference control for each SP. This maintains implementation simplicity by using standard precoding techniques while significantly improving interference control capability through structured precoding space allocation
Solution Approach 2:
The patent applies different precoding strategies to different SPs based on their specific service requirements and channel conditions. Each SP receives tailored precoding within its allocated subspace, optimizing interference control for each provider while maintaining overall system simplicity
Data Source
AI summary
A method and network node for distributed coordinated downlink precoding for multi-cell multiple input multiple output (MIMO) wireless network virtualization are disclosed. According to one aspect, a network node is configured to, in each of a plurality of successive transmission time periods: transmit to each of a plurality of SPs a corresponding set of channel information; receive from each of the plurality of SPs a service demand and a normalized precoding matrix, the normalized precoding matrix being determined by the corresponding SP based on the corresponding set of channel information; allocate a virtual transmit power to each of the plurality of SPs based at least in part on the received service demands and normalized precoding matrices; and determine a downlink precoding matrix to transmit messages to WDs, the downlink precoder matrix being based at least in part on the received service demands and normalized precoding matrices.