Cophase Space-Time Trellis Codes for MIMO Wireless Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current MIMO wireless communication systems lack effective coding schemes that utilize channel state information, particularly channel phase information, to achieve superior error performance and simple implementation, while existing solutions often incur high complexity and peak-to-average power ratio.
Innovation Solution
The development of cophase space-time trellis codes that incorporate channel phase feedback to design optimal inner and outer codes, combining the benefits of space-time coding and maximum ratio combining gain, using a new performance criterion for set partitioning and code construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If space-time block codes are used to provide full diversity, then reliability is improved, but coding gain is not provided
Solution Approach 1:
The code is segmented into multiple components including a space-time block code portion and a trellis coded modulation portion. The STBC component provides full diversity while the TCM component provides coding gain, allowing the system to achieve both reliability improvement and coding gain without excessive complexity
Solution Approach 2:
The invention merges space-time block coding with trellis coded modulation to create a hybrid scheme. This combination allows the system to simultaneously obtain the full diversity benefit from STBC and the coding gain from TCM, resolving the contradiction between reliability and performance
2Reliability
If space-time trellis codes are used to provide coding gain, then error performance is improved, but encoder and decoder complexity becomes extremely high
Solution Approach 1:
The coding function is segmented between a simple space-time block code portion and a trellis coded modulation portion. This segmentation allows the system to achieve coding gain through the TCM component while maintaining lower overall complexity compared to full space-time trellis codes
Solution Approach 2:
Different parts of the coding scheme have different complexity characteristics. The STBC portion provides diversity with low complexity, while the TCM portion provides coding gain with moderate complexity, creating a balanced local quality distribution that avoids extreme overall complexity
3Reliability
If beam forming schemes with optimal power loading are used, then error performance is improved, but peak-to-average power ratio increases significantly
Solution Approach 1:
The invention changes the power allocation parameters by using equal power loading across transmit antennas instead of optimal power loading. This parameter change reduces the peak-to-average power ratio while maintaining good error performance through the space-time coding structure
4Reliability
If channel state information is used at the transmitter to improve space-time transmission, then error performance is improved, but implementation complexity increases
Solution Approach 1:
The system uses quantized channel phase information locally at the transmitter to adjust the code selection, providing performance improvement without requiring full channel state information. This local quality approach balances performance and complexity by using only the necessary channel knowledge
Data Source
AI summary
A method for multiple-input-multiple-output (MIMO) wireless communication comprises the steps of generating inner and outer codes based on channel state information available at a transmitter and concatenating different inner codes with different outer codes; and using the generated concatenated inner and outer codes for wireless communication. The inner and outer codes are based on channel phase information at the transmitter or channel feedback. High-performance trellis codes or block codes for use in cellular networks are illustratively described. The space-time trellis codes are generated by set partitioning on a plurality of classes of signal designs to generate a series of inner codes, each of the series of inner codes being optimized by channel phase feedback, and concatenating each inner code with a multiple trellis coded modulated outer code to provide a complete space-time trellis code as a cophase space-time trellis code.