Downlink Superimposed Signal Decoding via Interference Cancellation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In downlink communication using superimposed radio signals, low-power user terminals struggle to decode their data streams due to interference from high-power data streams transmitted over the same resources, lacking necessary information to decode foreign data streams.
Innovation Solution
The method involves transmitting control information from the base station to user terminals to enable decoding of high-power data streams, where user terminals successively reduce and subtract high-power data signals from the superimposed signal, and use extended downlink control information formats to provide necessary information for decoding, allowing low-power terminals to extract their own data streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple user terminals transmit data streams using the same radio resources with different power levels, then spectral efficiency is improved, but low-power user terminals cannot decode their data streams due to interference from high-power data streams
Solution Approach 1:
The base station performs preliminary actions by determining pairing information between user terminals and providing control information to low-power user terminals before the decoding process. This includes identifying which high-power data streams are superimposed on the same resources and providing the necessary control information in advance, enabling the low-power terminal to successfully decode its data stream by subtracting the high-power interference components.
2Reliability
If control information for decoding foreign data streams is provided to low-power user terminals, then decoding capability is improved, but device complexity increases due to extended control information formats
Solution Approach 1:
The control information format is designed to serve multiple functions: it provides scheduling information for the low-power user terminal's own data stream and simultaneously provides the control information needed to decode superimposed high-power data streams from other user terminals. This multi-functionality approach avoids the need for separate control information structures, thereby managing complexity while enabling decoding capability.
3Productivity
If user terminals decode multiple superimposed data streams, then multi-user channel capacity is improved, but processing time increases due to successive interference cancellation operations
Solution Approach 1:
The base station performs preliminary pairing determination and provides control information to user terminals before the actual data reception and decoding process. By pre-identifying which high-power data streams are superimposed on the same resources as the low-power terminal and providing the necessary control information in advance, the terminal can efficiently perform successive interference cancellation without excessive processing delays.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention concerns a method for downlink communication between a base station and a user terminal by means of a downlink superimposed radio signal comprising downlink data for the user terminal and for at least one further user terminal that are transmitted using the same radio resources, wherein the downlink data for the user terminal are transmitted with lower power than the downlink data for the at least one further user terminal, and control information is sent in downlink from the base station to the user terminal that enables the user terminal to decode the downlink data for the at least one further user terminal, a base station, a user terminal and a communication network therefor.