Terminal PDSCH Demodulation Using Two-Stage Precoding
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Solution Overview
Problem
The constraint on the number of radio frequency (RF) chains in a base station limits the improvement of downlink throughput and connectivity in future radio communication systems, such as New Radio (NR).
Innovation Solution
A terminal is designed with a receiving section that processes demodulation reference signal (DMRS) information using a first precoder for beam application and a second precoder for superposing signals across multiple terminals, without applying the second precoder to the DMRS. The control section demodulates the physical downlink shared channel (PDSCH) based on the DMRS and information related to the second precoder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of RF chains is constrained, then device complexity is reduced, but downlink throughput and connectivity are limited
Solution Approach 1:
The precoding operation is segmented into two independent stages: a first precoder for beam formation and a second precoder for multi-user signal superposition. This segmentation allows the system to achieve advanced MIMO capabilities and improved downlink throughput through NOMA while using a constrained number of RF chains, as the DMRS only needs to support the first precoding stage rather than requiring separate reference signals for each precoding stage.
2Productivity
If NOMA is applied with two-stage precoding, then downlink throughput is improved, but DMRS processing complexity increases
Solution Approach 1:
The invention extracts the second precoding operation from the DMRS processing chain by applying it only to the data signal (PDSCH) while leaving the DMRS unchanged. This allows the terminal to receive DMRS information related to the first precoder only, simplifying the reference signal processing while still enabling the terminal to reconstruct the complete two-stage precoding effect for accurate PDSCH demodulation through the received precoder information.
Solution Approach 2:
The invention introduces precoder information as an intermediary element that carries the second precoding parameters separately from the DMRS. This intermediary allows the terminal to obtain the necessary information for demodulating the second precoding stage without requiring additional DMRS signals, thus avoiding increased DMRS processing complexity while maintaining improved downlink throughput capability.
Data Source
AI summary
A terminal according to an aspect of the present disclosure includes a receiving section that receives demodulation reference signal (DMRS) information relating to at least one resource of a DMRS, to which at least one DMRS a first precoder for a beam is applied and a second precoder for superposing signals for a plurality of terminals in the beam is not applied, and a control section that demodulates a physical downlink shared channel (PDSCH) to which the first precoder and the second precoder are applied, based on the DMRS and information relating to the second precoder. According to an aspect of the present disclosure, downlink throughput using the MIMO can be improved.