Space-Time Channel Encoders for Flexible Antenna Symbol Generation
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Solution Overview
Problem
Multiple antenna communication systems face challenges in maintaining low receiving complexity and flexibility as the number of antennas increases, particularly in achieving maximum diversity gain and data rate of 1, especially when using more than three transmitting antennas.
Innovation Solution
The proposed solution involves a symbol generation method using space-time and space-frequency channel encoders, along with an inverse fast Fourier transformer, which performs phase-shifting operations to generate phase-shifted codewords. This method allows for adaptive encoding based on channel states, enabling flexible operation with varying numbers of antennas while maintaining diversity gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of transmitting antennas is increased to more than three, then the diversity gain can be improved, but the receiving complexity increases considerably and the data rate cannot be maintained at 1
Solution Approach 1:
The patent segments the encoding function across multiple independent space-time channel encoders, each handling a specific channel. This segmentation allows the system to process multiple antennas through parallel independent encoding units, avoiding the need for complex centralized processing at the receiver while maintaining diversity gain across all antennas.
Solution Approach 2:
Each space-time channel encoder is designed as a universal unit that can handle multiple channels and antenna configurations. The encoders perform space-time encoding with respect to multiple space areas and time areas, and can apply different phase shifts, making them adaptable to various antenna numbers without requiring different receiver architectures.
2Reliability
If the number of transmitting antennas is increased to more than three, then the diversity gain can be improved, but the data rate cannot be maintained at 1
Solution Approach 1:
The patent segments the transmission across multiple independent channels, each processed by separate space-time channel encoders. This channel segmentation allows parallel data transmission through different spatial and temporal paths, maintaining overall data rate while achieving diversity gain through the combined effect of multiple channels.
Solution Approach 2:
The patent extends the encoding dimensionality by performing space-time encoding across multiple space areas and time areas simultaneously. This multi-dimensional encoding approach allows the system to achieve diversity gain through additional spatial and temporal dimensions without reducing the data transmission rate.
3Device complexity
If two respective Alamouti transmission blocks are used for four transmitting antennas, then the receiving complexity is reduced, but the diversity gain is lost
Solution Approach 1:
The patent introduces dynamic phase shifting capabilities to the space-time channel encoders, allowing the system to adaptively adjust phase values across different channels and antenna configurations. This dynamic phase adjustment enables the system to maintain optimal diversity gain while keeping the receiver structure simple and fixed.
Solution Approach 2:
The patent changes the encoding parameters by performing space-time encoding with respect to multiple space areas and time areas, and by applying different phase shifts to different channels. These parameter changes enable the system to achieve maximum diversity gain with simple receiver architecture, resolving the contradiction between receiving complexity and diversity gain.
4Adaptability or versatility
If space-time and space-frequency encoding operations are performed with multiple space areas and frequency areas, then the adaptability to different antenna configurations is improved, but the device complexity increases
Solution Approach 1:
The patent segments the encoding functionality into multiple independent space-time channel encoders, each handling a specific channel. This segmentation provides flexibility to accommodate different antenna configurations by simply activating or deactivating specific encoder units, rather than requiring a completely different encoding architecture for each configuration.
Solution Approach 2:
Each space-time channel encoder is designed as a universal unit capable of performing encoding operations across multiple space areas and time areas with configurable phase shifts. This universality allows the same encoder design to adapt to various antenna configurations (including 3, 4, 5, or more antennas) without requiring design changes, thereby providing flexibility without proportionally increasing complexity.
Data Source
AI summary
The present invention relates a symbol generation apparatus for multiple antennas having low receiving complexity and having flexibility with respect to an increase in the number of antennas. The symbol generation apparatus includes a plurality of space-time channel encoders respectively corresponding to a plurality of channels, and an inverse fast Fourier transformer group. The respective space-time channel encoders receive a digital-modulated symbol group from the corresponding channel, perform a space-time encoding operation with respect to a plurality of space areas and at least one time area, shift phases by using a plurality of phase values, and generate a plurality of phase-shifted space-time codewords. The inverse fast Fourier transformer group performs an inverse fast Fourier transform operation by using the plurality of phase-shifted space-time codewords in a plurality of subcarriers respectively corresponding to the plurality of channels, and generates a plurality of inverse fast Fourier transformed signals.