Uplink Communication Method Using Outdated Channel State Information
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Solution Overview
Problem
In cellular networks, using outdated channel state information (CSI) to improve communication capacity is challenging, especially in uplink scenarios where antennas are distributed differently, making it difficult for transmitters to reconfigure assistance signals for multiple receivers simultaneously.
Innovation Solution
A communication method for a 2-cell, K-user uplink scenario that involves transmitting and receiving specific linear combinations of data symbols across multiple time slots, using feedback signals to reconfigure assistance signals and decode data, thereby increasing communication capacity even with outdated CSI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If interference alignment technique is applied using predicted channel information from outdated CSI, then communication capacity is improved, but in fast-fading scenarios the current channel state may completely differ from predicted channel state, causing the prediction method to fail
Solution Approach 1:
The transmitter pre-configures multiple assistance signals corresponding to different possible channel states before actual transmission. When outdated CSI is received, the transmitter can quickly select or switch to the appropriate pre-configured assistance signal that matches the current channel conditions, avoiding the need for real-time prediction in fast-fading scenarios.
Solution Approach 2:
The system dynamically adapts the assistance signal selection based on the received outdated CSI and current channel conditions. The transmitter can switch between different assistance signals or linear combinations thereof, making the system flexible and adaptive to changing channel states rather than relying on static prediction.
2Productivity
If transmitters reconfigure assistance signals by combining past received signals in each receiver, then communication capacity increases, but in uplink scenarios with distributed antennas, transmitters cannot access signals from other transmitters to reconfigure assistance signals simultaneously
Solution Approach 1:
The receiver acts as an intermediary that collects signals from multiple transmitters, processes them locally to generate assistance signals, and then feeds back channel state information to transmitters. This eliminates the need for transmitters to directly access each other's signals, solving the distributed antenna access problem while still enabling assistance signal reconfiguration.
Solution Approach 2:
The system segments the assistance signal generation process: each transmitter independently generates its own assistance signal based on its local outdated CSI and received feedback, rather than requiring centralized coordination or direct access to other transmitters' signals. This segmentation enables distributed implementation while maintaining overall system performance.
Data Source
AI summary
Disclosed is a communication method of a terminal utilizing outdated channel information in a two-cell, three-user network environment, the method comprising: transmitting nine different first linear combinations to a first base station in each time slot during a first time interval; receiving a first feedback signal from a second base station which has received the first linear combination as an interference signal; transmitting four different second linear combinations to the first base station during a first sub-time interval of a third time interval; receiving a second feedback signal from the second base station which has received the second linear combinations as an interference signal; and transmitting reconfiguration signals consisting of eight data symbols to the first base station during a third sub-time interval of the third time interval. Further, a communication method of a base station corresponding to such a terminal is also disclosed.