LTE-A Terminal PDSCH Demodulation Using DRS in Absent CRS Subframes
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Solution Overview
Problem
In LTE-A only subframes, the absence of CRS prevents the use of fallback demodulation modes, hindering data transmission and reception for Rel-10 mobile stations during scheduling.
Innovation Solution
Implementing a method that allows demodulation using a demodulation reference signal (DRS) in LTE-A only subframes, enabling data reception by interpreting the subframe type and employing specific demodulation schemes based on subframe types, such as using DRS for LTE-A only subframes and CRS for mixed subframes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CRS is not transmitted in LTE-A only subframe to support Rel-10 mobile station, then Rel-10 mobile station can be scheduled in all subframes, but fallback demodulation mode cannot be used and device complexity increases
Solution Approach 1:
The patent changes the demodulation parameters (reference signal type and transmission scheme) based on the subframe type. For LTE-A only subframes, it uses DRS-based demodulation with specific transmission schemes, while for other subframes, it uses CRS-based fallback demodulation. This parameter adaptation allows Rel-10 mobile stations to be scheduled in all subframes without requiring complex demodulation capabilities in all conditions.
Solution Approach 2:
The patent segments the subframes into different types (LTE-A only subframes and other subframes) and applies different demodulation schemes to each segment. This segmentation allows the system to use simplified CRS-based demodulation in some subframes while using more advanced DRS-based demodulation in others, thereby reducing overall device complexity while maintaining scheduling flexibility.
2Productivity
If DCI format 1A is used for fallback mode in LTE-A only subframe, then scheduling can be performed, but transmission scheme is limited without CRS
Solution Approach 1:
The patent defines different transmission schemes for DCI format 1A based on subframe type. In LTE-A only subframes, it specifies particular transmission schemes that are compatible with DRS-based demodulation, while in other subframes, it allows the standard CRS-based fallback demodulation. This parameter adaptation enables scheduling in all subframes with appropriate transmission scheme flexibility.
3Device complexity
If single antenna port transmission is used in LTE-A only subframe, then device complexity is reduced, but transmission capacity is limited
Solution Approach 1:
The patent dynamically adjusts the transmission scheme based on the subframe type and mobile station capability. For LTE-A only subframes, it enables single antenna port transmission with DRS-based demodulation to reduce complexity, while allowing more advanced transmission schemes in other subframes. This dynamic adaptation optimizes the balance between device complexity and transmission capacity according to the specific operating conditions.
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AI summary
An apparatus for transmitting and receiving data in a wireless communication system method thereof are disclosed. In a terminal of a wireless communication system, the present invention includes receiving a physical downlink control channel (hereinafter abbreviated PDCCH), receiving a physical downlink shared channel ((hereinafter abbreviated PDSCH), and demodulating the PDSCH by interpreting the PDCCH according to a type of a subframe including the PDCCH and the PDSCH.