Uplink Transmit Diversity Scheme Selection for Orphan Symbols
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Solution Overview
Problem
In wireless communication systems, especially in MIMO systems, the efficient transmission of symbols in uplink subframes is hindered by the presence of orphan symbols, which disrupt the application of traditional transmit diversity schemes like STBC, leading to performance losses and increased complexity in receiver implementation.
Innovation Solution
The method involves determining the presence of orphan symbols in uplink subframes and adaptively selecting suitable transmit diversity schemes, such as SFBC, low-CM SFBC, CDD, or FSTD, to process and transmit symbols effectively via multiple antennas, ensuring efficient use of transmit diversity without requiring the base station to handle multiple schemes within a single subframe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional transmit diversity schemes like STBC are applied in uplink subframes with orphan symbols, then the transmission can proceed, but performance losses occur and receiver implementation complexity increases
Solution Approach 1:
The system dynamically selects between different transmit diversity schemes (STBC, SFBC, CDD, FSTD) based on the presence of orphan symbols in the uplink subframe. When orphan symbols are detected, the system switches from time-domain STBC to frequency-domain SFBC or other suitable schemes, allowing the receiver to adapt its processing accordingly and maintain performance while managing complexity.
Solution Approach 2:
The invention changes the diversity scheme parameter based on the subframe structure. By detecting orphan symbols and selecting appropriate schemes (STBC for normal subframes, SFBC/CDD/FSTD for subframes with orphan symbols), the system optimizes transmission reliability while enabling the receiver to use corresponding simplified processing methods for each scheme.
2Adaptability or versatility
If multiple transmit diversity schemes are supported within a single subframe, then adaptability improves, but base station processing complexity increases
Solution Approach 1:
The uplink subframe is segmented into different processing regions based on the presence of orphan symbols. The system divides the transmission into segments that can be handled by different diversity schemes, with the base station processing each segment according to its type, thereby maintaining adaptability while managing processing complexity through structured segmentation.
Solution Approach 2:
The base station dynamically determines which transmit diversity scheme was used by the UE based on subframe structure analysis. This dynamic determination allows the base station to adapt its receiving processing to match the transmitted scheme without requiring simultaneous support for multiple schemes in parallel, thus maintaining versatility while controlling processing complexity.
3Reliability
If transmit diversity is applied to maintain single-carrier waveform integrity, then signal quality improves, but system complexity increases
Solution Approach 1:
Different transmit diversity schemes are applied to different portions or conditions of the transmission based on local requirements. SFBC is used specifically for orphan symbols to maintain single-carrier waveform integrity where needed, while STBC can be used in other portions, allowing the system to maintain signal quality where critical while avoiding unnecessary complexity elsewhere.
Data Source
AI summary
Certain aspects of the present disclosure relate to a method for uplink wireless communications. In one aspect, a diversity scheme may be selectively and adaptively applied to an uplink transmission based on a determination of whether the uplink transmission comprises one or more orphan symbols. According to an aspect, the determination is made based on whether a sounding reference signal is received in the uplink subframe and whether the uplink subframe is configured with a normal or extended cyclic prefix.