Frequency-Independent Precoder Values for Wireless Network Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing coherent schemes for coordinating transmissions in wireless networks with distributed antenna infrastructures require perfect knowledge of channel coefficients between transmitting antennas and mobiles, leading to significant overhead and feedback requirements.
Innovation Solution
A precoder value processor determines frequency-independent, linear precoder values to achieve target average signal-to-interference noise ratios (SINR) across multiple wireless terminals with minimal total transmit power, using iterative procedures that maximize SINR for each terminal and minimize sum power, without requiring instantaneous channel knowledge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If perfect channel state information is used at the transmitter, then communication capacity is maximized, but feedback overhead and system complexity increase significantly
Solution Approach 1:
The patent performs preliminary channel diagonalization and precoder computation at the receiver side using available channel statistics, then only transmits compressed precoder information back to the transmitter. This preliminary action at the receiver reduces the amount of feedback needed while still achieving capacity-approaching performance.
Solution Approach 2:
The patent extracts only the essential precoder information from the full channel state information and transmits only this extracted component back to the transmitter. This extraction approach maintains communication performance while significantly reducing feedback overhead by eliminating redundant information transmission.
2Object-affected harmful factors
If coherent coordination schemes are implemented across multiple cells, then interference is reduced, but channel knowledge acquisition complexity and feedback requirements increase
Solution Approach 1:
The patent implements coordination based on local channel statistics and second-order information available at each cell, rather than requiring global perfect channel knowledge. This local quality approach enables interference coordination while reducing the complexity of channel knowledge acquisition across the network.
Solution Approach 2:
The patent uses statistical copies (covariance matrices) of channel characteristics instead of exact channel realizations for coordination purposes. This copying approach allows cells to coordinate interference management using simplified representations of channel conditions, reducing feedback and processing complexity.
3Measurement precision
If frequency-dependent precoding is used to optimize performance across all subcarriers, then SINR is maximized, but computational complexity and processing overhead increase
Solution Approach 1:
The patent applies precoding optimization selectively based on channel conditions and user requirements rather than uniformly across all subcarriers and users. This partial action approach achieves adequate SINR performance for critical transmissions while reducing unnecessary computational complexity in scenarios where full optimization is not required.
Solution Approach 2:
The patent segments the frequency band into groups and applies precoding strategies at the group level rather than individually for each subcarrier. This segmentation reduces computational complexity by processing fewer independent frequency units while still capturing the essential frequency-selective characteristics of the channel.
Data Source
Figure 1
Figure 2
AI summary
A wireless network (20) participates in radio frequency communication with plural wireless terminals (30). The network (20) comprises plural transmitters (40); a precoder value processor (42) configured to develop a set of precoder values; and a precoder (44) which uses the precoder values for coding the signals transmitted from the plural transmitters. The precoder value processor (42) is configured to develop a set of frequency-independent, linear precoder values for use in precoding signals transmitted from the plural transmitters (30). Each vector of the set is associated with one wireless terminal (30). The set of precoder values is determined such that a set of target average signal to interference noise (SINR) ratios is achieved by the plural wireless terminals with a predetermined total transmit power. Perferably, the predetermined total transmit power is minimum total transmit power.