Multi-User Random Access for Massive MIMO Control Channel Overload

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Solution Overview

Problem

Current LTE protocols are inadequate for supporting multi-user MIMO communications in 5G systems, as they overwhelm the common control channel with control resources, making initial access procedures inefficient for massive MIMO scenarios.

Innovation Solution

Implementing multi-user random access procedures that allow concurrent access requests from multiple UEs using multiple antennas, with a random access signal set, random access response PDCCH message, reciprocity reference signal set, and multi-user PDCCH, enabling efficient initial access and channel setup in massive MIMO systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If current LTE protocols are used for initial access in massive MIMO systems, then compatibility with existing systems is maintained, but the common control channel becomes overwhelmed with control resources

Engineering Contradiction:

Improvecompatibility with existing systemsVSAvoidcontrol channel resource overhead

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the control channel resources by introducing UE-specific control channels (C-PDCCH) alongside the common control channel (E-PDCCH). This segmentation allows control information to be distributed across multiple channels, preventing the common control channel from being overwhelmed while maintaining compatibility with existing LTE infrastructure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension to the control channel architecture by adding carrier aggregation support. Control information can now be transmitted on multiple carriers simultaneously, distributing the control resource burden across different frequency dimensions and reducing overhead on any single channel.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of operation

If multiple UEs transmit access requests concurrently using single antenna, then initial access procedure is simple, but spectral efficiency is limited

Engineering Contradiction:

Improvesimplicity of initial access procedureVSAvoidspectral efficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent introduces dynamic beamforming capabilities where UEs can switch between different antenna ports and beams during the random access procedure. This dynamic adaptation allows the system to optimize spectral efficiency by selecting the best transmission paths while maintaining procedural simplicity through automated beam management.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of antenna usage from fixed single-antenna operation to multi-antenna operation with configurable antenna ports. By allowing UEs to transmit on multiple antenna ports simultaneously or sequentially, the system achieves higher spectral efficiency without significantly complicating the access procedure.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If common control channel is used for all UE control messages, then protocol implementation is simplified, but control resource requirements increase

Engineering Contradiction:

Improveprotocol implementation complexityVSAvoidcontrol resource requirements

Core Design Contradiction:

Device complexityVSQuantity of substance

Solution Approach 1:

The patent segments control messages into common control information (transmitted on E-PDCCH) and UE-specific control information (transmitted on C-PDCCH). This segmentation reduces the resource burden on the common control channel while distributing control traffic efficiently across multiple dedicated channels.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent inverts the traditional approach by making the UE-specific control channel the primary channel for most control traffic, while the common control channel handles only essential system-wide information. This inversion reduces common channel overhead while maintaining protocol simplicity through standardized channel structures.

Inventive Principle:

Principle #13The other way round (Inversion)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution supports concurrent access requests from multiple UEs, improves spectral efficiency, and enables efficient channel setup, addressing the limitations of current LTE protocols in massive MIMO systems by utilizing multiple antennas for signaling and feedback.

Implementation Method 1

Based on electromagnetic properties, ideal channel reciprocity for a wireless communication channel between one of the base station antennas 104 and one of the UE antennas 108 will provide that the uplink (UL) channel and the downlink (DL) channel will have identical responses.

Methodology Applied

Scientific EffectElectromagnetic reciprocity: Electromagnetic Induction

Data Source

PatentUS10201020B2Multi-user random access procedures for massive MIMO wireless communication systems

Publication Date: 2019.02.05 NATIONAL INSTRUMENTS CORP

AI summary

A system and method for performing multi-user random access procedures in a mobile telecommunications network between a base station and a user equipment (UE) having a plurality of antennas includes transmitting a random access signal set (RASS) message using one or more antennas of the plurality of UE antennas. In response to receiving the RASS message, the base station transmitting a random access response physical downlink control channel (RAR-PDCCH) message. In response to receiving the RAR-PDCCH message, transmitting a reciprocity reference signal set (RRSS) signal using the plurality of UE antennas.