Uplink Multi-Antenna STTD Encoding for Wireless Transmission
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Solution Overview
Problem
Current wireless communication systems face challenges in achieving efficient uplink transmission using multiple antennas, particularly in providing robustness and higher data throughput without increasing transmit power, especially for control channels in UMTS systems.
Innovation Solution
The implementation of space-time transmit diversity (STTD) encoding across multiple antennas for uplink transmission, which involves encoding physical channels like E-DPDCH and E-DPCCH, and pre-coding techniques to distribute signals effectively across antennas, ensuring reliable transmission and balancing service quality across data and control channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple antenna techniques are adopted for uplink transmission, then robustness and data throughput are improved, but device complexity increases
Solution Approach 1:
The patent segments the uplink transmission by applying different processing techniques to different physical channels. Control channels (DPCCH, E-DPCCH, HS-DPCCH) use conventional single-antenna processing, while data channels (DPDCH, E-DPDCH) use STTD encoding on selected antennas. This segmentation allows the system to gain diversity benefits for data transmission without increasing complexity for control signaling.
Solution Approach 2:
The patent applies STTD encoding partially rather than to all channels. Specifically, it applies STTD to data channels only when configured to do so, while control channels maintain conventional processing. This partial application provides the diversity benefit where needed (data transmission) while avoiding the complexity overhead in other areas (control signaling).
2Reliability
If STTD encoding is applied to all physical channels, then transmit diversity is maximized, but peak-to-average power ratio increases
Solution Approach 1:
The patent applies STTD encoding selectively to specific physical channels (data channels) while excluding control channels from STTD processing. This local application ensures that the diversity benefit is concentrated where it provides the most value (data transmission) while avoiding the PAPR penalty in control channel transmission.
Solution Approach 2:
The patent implements partial STTD encoding by applying the technique only to configured data channels rather than all physical channels. This partial action provides transmit diversity for data transmission while maintaining acceptable PAPR levels by excluding control channels from the STTD processing chain.
Data Source
AI summary
Method and apparatus for uplink transmission using multiple antennas are disclosed. A wireless transmit/receive unit (WTRU) performs space time transmit diversity (STTD) encoding on an input stream of a physical channel configured for STTD. Each physical channel may be mapped to either an in-phase (I) branch or a quadrature-phase (Q) branch. The WTRU may perform the STTD encoding either in a binary domain or in a complex domain. Additionally, the WTRU may perform pre-coding on at least one physical channel including the E-DPDCH with the pre-coding weights, and transmitting the pre-coded output streams via a plurality of antennas. The pre-coding may be performed either after or before spreading operation.