Pre-coding Indicator Channel for Multi-User MIMO Interference Suppression
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Solution Overview
Problem
Current wireless communication systems, particularly in 3GPP LTE, face challenges in efficiently suppressing inter-user interference in multi-user MIMO configurations due to the lack of pre-coding vector information sharing between user equipment, leading to suboptimal spectral efficiency and increased interference.
Innovation Solution
A pre-coding indicator channel is introduced to transmit pre-coding matrix indices or vector information over a shared downlink channel, allowing user equipment to determine and actively suppress inter-user interference by using a predefined codebook, thereby reducing interference and enhancing spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If pre-coding vector information is shared between user equipment, then inter-user interference suppression is improved, but device complexity and signaling overhead increase
Solution Approach 1:
The patent extracts only the essential pre-coding vector information (indices rather than full vectors) and transmits it through a dedicated pre-coding indicator channel. This selective extraction of necessary information allows UEs to suppress interference without requiring complete knowledge of other UEs' pre-coding vectors, thereby reducing device complexity while maintaining interference suppression capability.
Solution Approach 2:
The patent introduces a pre-coding indicator channel as an intermediary mechanism that facilitates the exchange of pre-coding vector information between the network and user equipment. This intermediary channel provides a structured and efficient pathway for information sharing, reducing the complexity of direct peer-to-peer information exchange between UEs while enabling effective interference suppression.
2Productivity
If pre-coding matrix indices are transmitted over shared downlink channel, then spectral efficiency is improved, but channel capacity and resource availability are consumed
Solution Approach 1:
The patent transmits pre-coding matrix indices rather than full pre-coding vectors, significantly reducing the number of bits required for transmission. By changing the parameter from complete vector information to compact index representation, the system achieves interference suppression capability while consuming minimal channel capacity, thereby improving spectral efficiency without depleting available resources.
Solution Approach 2:
The patent uses lightweight index indicators that can be quickly transmitted and discarded, rather than transmitting heavy pre-coding vector data. These index indicators serve their purpose of enabling interference suppression and can be regenerated in subsequent transmissions, effectively using minimal channel resources to achieve the desired performance improvement.
3Productivity
If user equipment actively suppresses inter-user interference, then data transmission rates are improved, but processing requirements and computational load increase
Solution Approach 1:
The patent enables UEs to perform preliminary interference suppression by providing them with pre-coding vector information in advance through the pre-coding indicator channel. With this prior knowledge, UEs can pre-process received signals to cancel out known interference components before main data processing, thereby achieving higher data transmission rates while reducing the computational load during primary signal processing operations.
Data Source
AI summary
Messages containing interference vectors are transmitted efficiently to user equipments over a downlink channel. A pre-coding indicator channel is used for transmission in an over-the-air packet-based communication system. A table of pre-coding matrix indices or pre-coding vector information is transmitted to user equipments configured in a spatially multiplexed multiple user MIMO configuration. The UEs receive the pre-coding vector information that allows them to determine the pre-coding vectors used to communicate in the downlink direction from a MIMO base station to other MIMO UEs in the cell or system. The UEs use this information to actively suppress inter-user interference.