Space-Time Coding for Multi-Cell Interference Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cellular wireless communication systems face challenges in achieving high data rates and reducing interference for mobile terminals at the cell edge due to strong interference and low signal-to-noise ratio, particularly in future OFDM-based systems where traditional macro-diversity techniques are not directly applicable.
Innovation Solution
The method involves applying space-time or space-frequency coding to data transmitted from multiple cell-sites using different antennas, with synchronized pilot signals and beamforming to derive channel estimates, allowing mobile terminals to combine signals from multiple sources for improved reception quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frequency re-use factor is increased to reduce interference at cell edge, then interference to neighboring cells is reduced, but spectral efficiency decreases
Solution Approach 1:
The patent introduces space-time coding across multiple antennas and time slots, transforming the problem from a frequency-domain resource allocation issue to a space-time domain signal processing issue. This allows the system to maintain frequency re-use factor of one while achieving interference mitigation through spatial diversity and temporal coding, thus resolving the contradiction between interference reduction and spectral efficiency
Solution Approach 2:
The patent changes the transmission parameters by applying space-time codes that transform the same data across multiple antennas and time slots. This parameter transformation allows the receiver to combine signals constructively while suppressing interference, achieving both high spectral efficiency and interference mitigation without requiring frequency partitioning
2Reliability
If space-time coding is applied across multiple antennas, then signal reception quality is improved, but system complexity increases
Solution Approach 1:
The patent segments the transmitted data into multiple coded streams that are sent across different antennas and time slots. Each antenna transmits a simplified version of the coded data, and the receiver segments and combines these streams. This segmentation approach improves reception quality through diversity while keeping individual transmitter and receiver components relatively simple
Solution Approach 2:
The space-time coding scheme provides multiple functions simultaneously: it enables diversity combining for improved reception, provides interference mitigation through orthogonal coding, and maintains compatibility with existing OFDM infrastructure. This multi-functionality achieves reliability improvement without proportionally increasing system complexity
Data Source
Figure 1~2
AI summary
The present invention relates to space-time or space-frequency coding in cellular systems. The same data is transmitted from different antennas with different coverage areas, corresponding to different cells. The different data streams have different parts of the space-time block codes applied. A mobile terminal can combine the different parts of the space-time block codes in different received signals. This provides better performance than the known techniques for single frequency networks. The invention can also be applied to antennas with different coverage areas from the same site, and different beams formed with antenna arrays.