Distributed MIMO Receiver Using Cross-Band Repeater for Rank Limits
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Solution Overview
Problem
Existing wireless communication systems, particularly 5G NR, face challenges in achieving maximum MIMO gain due to rank constraints in the channel between base stations and user equipment, limiting the transmission of multiple layers of data.
Innovation Solution
Implementing a distributed MIMO receiver system with a repeater that operates on a different frequency band to receive and re-transmit RF signals, allowing for a distributed high-rank MIMO configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single base station transmits data to a UE using conventional MIMO, then the system is simple to implement, but the data transmission is limited by the rank constraint of the channel (maximum min(Nt, Nr) layers)
Solution Approach 1:
The patent divides the MIMO receiver function into multiple distributed UEs, where each UE has fewer antennas but collectively they provide the equivalent of a high-rank receiver. The base station transmits to multiple UEs simultaneously, and the UEs cooperate to achieve high-rank MIMO performance without requiring a single complex high-antenna device
Solution Approach 2:
The patent introduces a distributed MIMO coordination mechanism that acts as an intermediary between the base station and multiple UEs. This coordination enables the UEs to share received signals and jointly process data, effectively creating a virtual high-rank receiver without requiring direct high-complexity hardware at each UE
2Productivity
If the UE uses all available antennas for receiving signals on the same frequency band, then the MIMO rank is maximized, but the signals interfere with each other due to the same frequency band
Solution Approach 1:
The patent moves the repeated signal transmission to a different frequency band dimension. By transmitting the same data on different frequency bands, the system avoids time-domain and frequency-domain interference while maintaining spatial diversity, effectively adding a frequency dimension to the MIMO operation
3Productivity
If the system transmits L layers of data with L > Nr1, then the data throughput increases, but the channel rank constraint prevents successful reception
Solution Approach 1:
The patent merges the receiving capabilities of multiple UEs with Nr1 and Nr2 antennas respectively, creating a combined virtual receiver with total antennas Nr1 + Nr2. This merged receiving capability allows the system to successfully decode L layers of data where L exceeds individual UE antenna counts, thereby achieving both high throughput and reliable reception
Data Source
AI summary
In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The UE receives Nr1 RF signals at Nr1 antennas on a first time-frequency resource. The Nr1 RF signals carrying L layers of data generated at a base station. Nr1 and L are positive integers. L is greater than Nr1. The UE receives Nr2 RF signals at the Nr2 antennas on a second time-frequency resource. The Nr2 RF signals carries the L layers of data. Nr2 is a positive integer. The UE obtains Nr1 baseband signals from the Nr1 RF signals. The UE obtains Nr2 baseband signals from the Nr2 RF signals. The UE determines the L layers of data based on the Nr1 baseband signals and the Nr2 baseband signals.