HSDPA Closed Loop Antenna Feedback Mechanism
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Solution Overview
Problem
Current closed loop transmit diversity modes in HSDPA systems, particularly in 3GPP Releases 5 and 6, face challenges with antenna verification and feedback resolution due to the UE's lack of knowledge about the antenna weights used by the Node B, compounded by the non-mandatory support for CLM1 and CLM2 in F-DPCH, making closed loop transmit diversity unusable for HSDPA.
Innovation Solution
Enhancing the HSDPA system by allowing the UE to send closed loop antenna transmit feedback information on the UL HS DPCCH, modifying the DL HS SCCH to include antenna weight information, and supporting MIMO multi-stream closed loop feedback, enabling dynamic feedback rates and reducing antenna verification issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If closed loop transmit diversity modes are implemented in HSDPA systems, then antenna diversity performance is improved, but antenna verification becomes unreliable due to UE's lack of knowledge about antenna weights
Solution Approach 1:
The patent implements a feedback mechanism where the UE sends closed loop antenna transmit feedback information on the UL HS DPCCH, and the Node B transmits antenna weight information on the DL HS SCCH. This bidirectional feedback enables the UE to verify the actual antenna weights being used, resolving the verification reliability issue while maintaining diversity performance
Solution Approach 2:
The patent introduces antenna weight information as an intermediary element that mediates between the Node B's transmit antenna operation and the UE's verification process. By transmitting this intermediate information through the DL HS SCCH, the system enables accurate verification without compromising the closed loop diversity mechanism
2Device complexity
If CLM1 and CLM2 are made non-mandatory for F-DPCH, then device complexity is reduced, but closed loop transmit diversity becomes unusable for HSDPA
Solution Approach 1:
The patent makes the closed loop transmit diversity mechanism universally applicable to HSDPA by implementing it through the existing UL HS DPCCH and DL HS SCCH channels, which are standard components of HSDPA. This approach does not require mandatory CLM1/CLM2 support, yet maintains full HSDPA compatibility through multi-functional use of standard channels
Solution Approach 2:
The patent introduces dynamic feedback rates for antenna weight information transmission, allowing the system to adapt its operation based on channel conditions and traffic requirements. This dynamic approach enables flexible implementation without mandatory CLM support, balancing complexity and versatility
3Measurement precision
If feedback resolution is increased for antenna control, then antenna weight precision is improved, but feedback information overhead increases
Solution Approach 1:
The patent transmits antenna weight information partially, only when changes occur or when explicitly requested by the UE. This partial action approach provides sufficient precision for verification purposes without continuously transmitting full antenna weight data, thereby reducing feedback overhead while maintaining adequate precision
Data Source
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AI summary
A method includes determining weights corresponding to each of a plurality of antennas used to transmit data signals, each weight suitable to modify a corresponding one of the data signals prior to transmission using a corresponding one of the antennas; and transmitting information corresponding to at least one of the weights, the information allowing at least the at least one weight to be determined. Another method includes receiving information corresponding to at least one of a plurality of weights, the plurality of weights corresponding to a plurality of first antennas used to transmit first data signals, where each weight was used to modify a corresponding one of the first data signals prior to transmission using a corresponding one of the first antennas; using the received information, determining the plurality of weights corresponding to the plurality of first antennas; and using at least the plurality of weights; and decoding second data signals received using a plurality of second antennas to create at least one output signal.