Wireless Channel State Feedback via Cyclic Shift Segmentation
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Solution Overview
Problem
Conventional wireless communication systems face challenges in generating adequate feedback information for cooperative communication, as the channel states calculated based on reference signals from individual base stations differ when multiple base stations cooperatively transmit signals, leading to inadequate feedback during cooperative communication.
Innovation Solution
A wireless communication system that includes at least two first communication devices and one second communication device, where the first communication device generates reference signals and transmits them to the second device, which measures the channel state including interference from other first communication devices, and determines communication parameters using these measurements to generate adequate feedback information for cooperative or non-cooperative communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the same frequency is repeatedly used for each cell to enhance frequency use efficiency, then frequency use efficiency is improved, but inter-cell interference increases for mobile terminals in cell edge regions
Solution Approach 1:
The patent segments the reference signal resources by assigning different cyclic shifts to reference signals from different base stations. This segmentation allows the mobile terminal to distinguish between desired signal and interfering signal at the same frequency, enabling accurate channel state measurement while maintaining high frequency reuse efficiency across cells
Solution Approach 2:
The patent changes the parameter of cyclic shift applied to reference signals from different base stations. By varying the cyclic shift parameter, the system enables the mobile terminal to separate and measure channel states of different base stations independently, even when they transmit on the same frequency, thus resolving the interference problem while maintaining frequency efficiency
2Device complexity
If channel state is calculated based on reference signals from individual base stations, then channel state measurement is simplified, but feedback information becomes inadequate for cooperative communication
Solution Approach 1:
The patent applies preliminary action by pre-configuring different cyclic shifts for reference signals from different base stations before cooperative communication occurs. This preliminary differentiation enables the mobile terminal to separately measure and report channel states for each base station, providing adequate feedback information for cooperative communication without increasing measurement complexity
Solution Approach 2:
The patent implements feedback by having the mobile terminal measure channel states for multiple base stations using differently cyclic-shifted reference signals and report these measurements back to the base stations. This feedback mechanism provides the necessary channel state information for cooperative communication while maintaining simple measurement procedures through the use of distinct cyclic shifts
Data Source
AI summary
A wireless communication system includes a first channel state measurer and a second channel state measurer. When a second communication device measures a state of a channel between the second communication device and a first communication device using reference signals transmitted from the first communication device, the first channel measurer is configured to measure a state of the channel including an interference due to a signal transmitted from another first communication device. When measuring the state of the channel between the second communication device and the first communication device using the reference signals transmitted from the first communication device, the second channel state measurer measures the state of the channel while suppressing the interference due to the signal transmitted from the another first communication device. Accordingly, the wireless communication system can generate adequate feedback information both when cooperative communication is performed and when cooperative communication is not performed.