DMRS Length Adaptation for Flexible MU-MIMO Scheduling
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Solution Overview
Problem
The existing MU-MIMO technology in LTE systems faces limitations in resource scheduling due to the requirement that the number of physical resource blocks allocated for uplink signals must be an integral multiple of the number of terminal devices, restricting flexibility in bandwidth allocation when using Interleaved Frequency Division Multiple Access (IFDMA).
Innovation Solution
The method involves generating and transmitting demodulation reference signals (DMRS) with lengths determined by the number of physical resource blocks and terminal devices, allowing for flexible allocation of physical resource blocks on the PUSCH channel, even when the number is not divisible by the total number of terminal devices, thereby adapting IFDMA multiplexing to MU-MIMO systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Interleaved Frequency Division Multiple Access (IFDMA) is used to multiplex uplink signals from multiple terminal devices in MU-MIMO, then the system can support multiple users simultaneously, but the number of physical resource blocks allocated must be an integral multiple of the number of terminal devices, limiting scheduling flexibility
Solution Approach 1:
The patent segments the DMRS into multiple parts, where each part corresponds to a specific terminal device. This segmentation allows the total DMRS length to be divided among multiple users without requiring the physical resource block count to be an integral multiple of the number of users, thereby resolving the scheduling flexibility constraint.
Solution Approach 2:
The patent changes the parameter of DMRS length from a fixed value to a variable value that can be dynamically adjusted based on the number of physical resource blocks and the number of terminal devices. This parameter change enables flexible resource allocation while maintaining system functionality.
2Adaptability or versatility
If the number of physical resource blocks is restricted to be divisible by the total number of terminal devices, then the resource allocation is simplified, but the bandwidth allocation flexibility is reduced
Solution Approach 1:
The patent introduces dynamic adjustment of the DMRS length based on the actual number of physical resource blocks and terminal devices. This dynamic approach allows the system to adapt to different resource allocation scenarios without requiring rigid divisibility constraints, thereby improving bandwidth allocation flexibility while maintaining operational simplicity through automated length calculation.
3Adaptability or versatility
If traditional DMRS length calculation is used, then the reference signal generation is straightforward, but it cannot support flexible physical resource block allocation in MU-MIMO systems
Solution Approach 1:
The patent makes the DMRS length determination universal by establishing a unified calculation method that works for any number of physical resource blocks and terminal devices. The formula-based approach provides multi-functionality, accommodating various MU-MIMO scenarios without requiring device-specific or scenario-specific length calculations, thus improving adaptability while keeping the determination process manageable.
Data Source
AI summary
Embodiments of the present disclosure provide a method for multiple input multiple output (MIMO) communications. For example, scheduling information is received at a terminal device from a network device, the scheduling information at least indicates physical resource blocks shared by a demodulation reference signal (DMRS) of the terminal device and a further DMRS of at least one further terminal device, and different sub-carriers allocated to the DMRS and the further DMRS in each of physical resource blocks, and the number of physical resource blocks is indivisible by a total number of the terminal device and the at least one further terminal device. The DMRS is generated, and a length of the DMRS is determined based on the number of physical resource blocks and the number of at least one further terminal device. The DMRS is transmitted to the network device on the sub-carriers allocated to the DMRS in the physical resource blocks. A corresponding method implemented at a network device such as a base station, and a terminal device and network device capable of implementing the above methods are also disclosed.