Uplink Pilot Allocation for Massive MIMO Interference Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Massive MIMO systems face limitations in multi-cell time division multiplexing due to pilot pollution, leading to inter-cell interferences in both uplink and downlink communications, which cannot be effectively eliminated by existing methods, especially as the number of users increases.
Innovation Solution
An apparatus and method for wireless communication that allocates uplink pilot sequences based on the geographical location of communication devices, allowing for spatial multiplexing and reducing interferences by using unique pilot sequences for each cell partition, thereby improving channel estimation accuracy and system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pilot sequences are reused among different cells to support more users, then the number of supported communication devices increases, but inter-cell interferences occur due to pilot pollution
Solution Approach 1:
The base station divides the cell into multiple cell partitions and allocates different uplink pilot sequences to different cell partitions. This segmentation allows the system to support more users by reusing pilot sequences across partitions while reducing inter-cell interference through location-based differentiation.
Solution Approach 2:
The patent applies location-specific pilot sequence allocation where each cell partition receives pilot sequences tailored to its geographical location. This local quality approach enables pilot reuse in different locations while maintaining orthogonality within each partition, thus supporting more devices without causing interference.
2Measurement precision
If the number of orthogonal pilots is increased to reduce pilot pollution, then channel estimation accuracy improves, but the pilot length is limited by coherent length
Solution Approach 1:
The patent introduces spatial dimension (cell partition location) as an additional degree of freedom for pilot sequence differentiation. Instead of only increasing pilot length or using more orthogonal sequences in the time domain, the system utilizes location-based partitioning to enable pilot reuse while maintaining estimation accuracy.
3Productivity
If pilot sequences are reused in adjacent cells to increase system capacity, then more users can be supported, but the base station cannot distinguish pilot signals effectively
Solution Approach 1:
The base station performs preliminary channel estimation using received pilot sequences to determine the communication device's cell partition location before data detection. This preliminary action enables the system to distinguish between pilots from different locations even when sequences are reused, preventing loss of signal distinguishability.
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
Provided in the present invention are an apparatus and method for use in radio communication, an electronic device, and a method for use with the electronic device. The apparatus comprises: a location determination unit, which is configured to determine a cell subdivision corresponding to the geographic location of a communication device, where each cell comprises multiple cell subdivisions; and, a pilot determination unit, which is configured to determine an uplink pilot sequence corresponding to the cell subdivision as the uplink pilot sequence of the communication device.