Varying-Rank Resource Allocation for Uplink Multi-User MIMO
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional MIMO communication systems allocate resources based on a fixed rank, which fails to account for differences in channels between devices, resulting in insufficient spectral and resource allocation efficiency.
Innovation Solution
A method for allocating different rank values for each frequency resource to user equipment (UE) in a 5G communication system, where a base station performs channel estimation using sounding reference signals and transmits uplink grants with resource block group (RBG) bitmaps to UEs, allowing varying rank allocation for improved resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed rank is allocated to all frequency resources for a UE, then the resource allocation process is simple, but the spectral efficiency and resource allocation efficiency are insufficient
Solution Approach 1:
The frequency resources allocated to a UE are divided into multiple segments (first frequency resource and second frequency resource), each with its own rank value. This segmentation allows different rank values to be applied to different frequency resource segments, thereby improving spectral efficiency without requiring a complete redesign of the resource allocation system.
Solution Approach 2:
Different rank values are assigned to different frequency resource segments based on local channel conditions. The base station performs channel estimation for each frequency resource and allocates appropriate rank values locally, rather than applying a uniform rank globally. This local quality approach optimizes resource allocation efficiency while maintaining manageable system complexity.
2Productivity
If different rank values are allocated to different frequency resources, then resource allocation efficiency is improved, but the complexity of resource allocation increases
Solution Approach 1:
The base station performs channel estimation in advance using sounding reference signals (SRS) before allocating frequency resources and rank values to UEs. This preliminary action of channel estimation provides the necessary information for efficient resource allocation, reducing the processing complexity during the actual resource allocation phase while maintaining high resource allocation efficiency.
Solution Approach 2:
Sounding reference signals (SRS) serve as an intermediary that carries channel information from UEs to the base station. By using SRS as the intermediary for channel estimation, the base station can efficiently obtain channel state information without direct complex measurements, thereby improving resource allocation efficiency while keeping processing complexity manageable.
3Measurement precision
If channel estimation is performed using sounding reference signals, then accurate channel information is obtained, but the overhead and signaling complexity increase
Solution Approach 1:
The sounding reference signals (SRS) serve multiple functions: they provide channel estimation information for rank allocation, support uplink channel quality assessment, and enable the base station to determine appropriate resource allocation strategies. This multi-functionality reduces the need for separate reference signals for different purposes, thereby improving measurement precision while controlling reference signal overhead.
Data Source
AI summary
An operating method of a base station includes performing channel estimation on a plurality of user equipment (UEs) based on a plurality of sounding reference signals (SRSs), allocating a first frequency resource and a second frequency resource based on a result of the channel estimation, the first frequency resource and the second frequency resource corresponding to a first UE among the plurality of UEs, and a rank value of the first frequency resource being different from a rank value of the second frequency resource, and transmitting an uplink grant to the first UE, the uplink grant including a plurality of resource block group (RBG) bitmaps to the first UE.