Uplink MIMO Transport Format Selection with Inter-Stream Interference
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Solution Overview
Problem
In uplink multiple-input multiple-output (ULMIMO) systems, existing methods for selecting a transport format in dual-stream transmission modes do not effectively consider inter-stream interference, leading to increased signal interference noise ratio and prolonged demodulation times at the base station, with existing solutions either wasting transmit power or requiring excessive downlink channel resources.
Innovation Solution
A method where a user equipment receives a reference E-TFC set and primary-stream channel quality difference from a base station, calculates transmit power offsets, and selects a transport format combination indicator that minimizes interference, allowing for efficient data transmission by considering inter-stream interference and maximizing transmit power utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing E-TFC selection solution is used in dual-stream transmission mode, then transmit power is wasted and demodulation duration is prolonged, but considering inter-stream interference increases signal interference noise ratio
Solution Approach 1:
The base station pre-calculates and delivers reference E-TFC sets for both single-stream and dual-stream modes to the UE. This preliminary preparation allows the UE to quickly determine the appropriate transport format without real-time interference calculation, reducing demodulation duration while accounting for inter-stream interference effects.
Solution Approach 2:
The patent creates a reference E-TFC set for dual-stream mode that mirrors the structure and calculation methodology of the single-stream reference E-TFC set. By copying the established single-stream selection mechanism and adapting it for dual-stream conditions, the system maintains consistency while addressing interference-specific requirements.
2Reliability
If base station delivers channel quality difference to UE for E-TFC selection, then inter-stream interference is considered, but downlink channel resources are excessively occupied
Solution Approach 1:
The reference E-TFC sets serve multiple functions: they provide both the basis for E-TFC selection and implicitly convey channel quality information. By making the reference sets multi-functional, the system eliminates the need for separate downlink channels to transmit quality differences, thus reducing downlink resource consumption while maintaining reliable interference consideration.
Solution Approach 2:
The patent merges the channel quality information delivery function with the existing reference E-TFC set delivery mechanism. Instead of using separate downlink resources to convey quality differences, this information is integrated into the reference set parameters themselves, combining multiple functions into a single transmission process.
3Reliability
If outer loop power control is used to increase signal interference noise ratio, then dual-stream demodulation is improved, but transmit power is wasted and process duration is prolonged
Solution Approach 1:
The reference E-TFC sets are pre-calculated to incorporate the necessary power adjustments for dual-stream conditions. This preliminary action embeds the power control effects directly into the reference parameters, eliminating the need for iterative outer loop power control processes and reducing both time loss and power waste.
Data Source
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AI summary
A method for selecting a transport format in an uplink multiple-input multiple-output system and a related method and a device are used by a user equipment to select a transport format in a case in which the user equipment is in a dual-stream transmission mode of the ULMIMO and inter-stream interference is considered. The method includes: receiving, by the user equipment, a reference E-TFC set and a primary-stream channel quality difference in the dual-stream transmission mode that are sent by a base station; acquiring Aed2 according to an SG allocated by the base station to the user equipment within a TTI; if transmit power of the primary stream is obtained according to primary-stream transmit power granted by the base station, acquiring E-TFCI1 according to the primary-stream channel quality difference and the Aed2; if the transmit power of the primary stream is obtained according to remaining transmit power, which is calculated according to a limit value of maximum transmit power of the user equipment, calculating Aedʹ2according to the remaining transmit power; calculating Aedm1ʹ2according to the primary-stream channel quality difference, the Aed2, and the Aedʹ2; calculating E-TFCI1ʹ according to the reference E-TFC set and the Aedm1ʹ2; and selecting from the E-TFCI1 and the E-TFCI1ʹan indicator, which has a smaller value, as an E-TFCI1ʺ, and selecting a transmission block size corresponding to the E-TFCI1ʺ.