Downlink Antenna Diversity for EUL Control Channel Reliability
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Solution Overview
Problem
Current mobile communication systems, particularly in W-CDMA and CDMA2000, lack specifications for applying transmission antenna diversity to Enhanced Uplink (EUL) channels such as E-HICH, E-RGCH, and E-AGCH, which affects radio communication quality and capacity.
Innovation Solution
Implementing closed loop transmission antenna diversity on dedicated downlink channels and open loop transmission antenna diversity, specifically Space Time Block Coding (STTD), for E-HICH, E-RGCH, and E-AGCH channels to optimize radio communication quality and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If closed loop transmission antenna diversity is applied to all downlink channels, then radio communication quality improves, but system complexity increases and feedback overhead increases
Solution Approach 1:
The patent applies different transmission antenna diversity schemes to different downlink channels based on their specific requirements. Closed loop transmission antenna diversity is applied to dedicated channels (DPDCH, DPCCH) where feedback is available, while open loop transmission antenna diversity is applied to common channels (E-HICH, E-RGCH, E-AGCH) where feedback is not available. This localized application optimizes radio communication quality for each channel type without unnecessarily increasing system complexity across the entire system.
2Reliability
If closed loop transmission antenna diversity is applied to dedicated channels, then radio communication quality improves, but feedback information requirements increase
Solution Approach 1:
The patent applies closed loop transmission antenna diversity only to dedicated channels (DPDCH, DPCCH) where mobile stations can provide feedback information, rather than universally to all downlink channels. This selective application ensures that feedback information is only required where it can actually be provided, improving radio communication quality for dedicated channels without creating unnecessary feedback information requirements for common channels where feedback is not available.
3Device complexity
If open loop transmission antenna diversity is applied to common channels, then system complexity is reduced, but radio communication quality improvement is limited
Solution Approach 1:
The patent applies open loop transmission antenna diversity to common channels (E-HICH, E-RGCH, E-AGCH) where feedback information is not available, accepting the limitation in radio communication quality improvement in exchange for reduced system complexity. This is the appropriate choice for common channels that serve multiple mobile stations and cannot accommodate individual feedback loops, while still providing diversity benefits through the open loop approach.
4Productivity
If transmission antenna diversity is applied to E-HICH, E-RGCH, and E-AGCH channels, then capacity of mobile communication system increases, but specifications and standardization complexity increase
Solution Approach 1:
The patent applies transmission antenna diversity to E-HICH, E-RGCH, and E-AGCH channels using open loop schemes, which increases the capacity of the mobile communication system by improving reliability of these control channels. The open loop approach avoids the need for complex feedback mechanisms for these specific channels, thereby limiting the increase in specifications and standardization complexity to only what is necessary for implementing open loop diversity on these channels, rather than requiring complex feedback specifications for all downlink channels.
Data Source
AI summary
An object of the present invention is to specify how a transmission diversity station that implements an EUL should apply a transmission antenna diversity to an E-HICH, an E-RGCH and an E-AGCH. The present invention relates to a mobile communication method for transmitting a signal from a base station to a mobile station via a downlink. In the method, a closed loop transmission antenna diversity is applied to a dedicated channel of the downlink, and an open loop transmission antenna diversity is applied to a control channel of the downlink in conformity with an uplink high efficient transmission method.