Precoding for TDD Interference Compensation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Time Division Duplex (TDD) systems in mobile telecommunication networks face significant interference issues due to varying propagation delays and asymmetric traffic patterns, limiting their adaptability and spectral efficiency compared to Frequency Division Duplex (FDD) systems.

Innovation Solution

A method is introduced to compensate for interference by determining and utilizing channel state information (CSI) between base stations and user equipment, allowing for encoding data signals to be partially orthogonal, enabling flexible switching points and reducing interference through precise encoding and beamforming techniques, even in TDD systems with variable switching points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If TDD systems use variable switching points to adapt to asymmetric traffic patterns, then adaptability and spectral efficiency are improved, but interference from varying propagation delays increases

Engineering Contradiction:

Improveadaptability to asymmetric traffic patternsVSAvoidinterference from varying propagation delays

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by determining channel state information between base stations before data transmission occurs. This advance knowledge of the interference channel allows the system to pre-calculate precoding matrices that will cancel interference at the intended receiver, thus resolving the interference problem caused by variable switching points while maintaining adaptability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter of channel state information by determining and utilizing CSI between base stations (BS-BS CSI) in addition to traditional channel state information. This parameter change enables the system to adapt to variable switching points and asymmetric traffic patterns while compensating for propagation delay variations through dynamic precoding adjustments

Inventive Principle:

Principle #35Parameter changes

2Productivity

If channel state information between base stations is determined and utilized for encoding, then interference is reduced and spectral efficiency is improved, but signaling overhead increases

Engineering Contradiction:

Improvespectral efficiencyVSAvoidsignaling overhead

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent merges the determination of channel state information between base stations with the existing channel state information feedback mechanism. By combining BS-BS CSI acquisition with traditional CSI feedback, the system achieves interference reduction and improved spectral efficiency without requiring a separate, overhead-intensive signaling channel for base station communication

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If cooperative antenna networks are implemented to reduce inter cell interference, then SINR for user equipment is increased, but system complexity increases

Engineering Contradiction:

ImproveSINR for user equipmentVSAvoidsystem complexity for coordinated processing

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces channel state information between base stations as an intermediary element that enables coordinated processing without requiring direct complex communication and coordination between base stations. The BS-BS CSI acts as a mediator that allows interference cancellation through precoding while simplifying the coordination overhead between cooperating base stations

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP2389747B1Precoding in telecommunication network

Publication Date: 2020.05.06 NOKIA SOLUTIONS & NETWORKS OY

Figure 1a
Figure 1b
Figure 1c

AI summary

It is described a method for compensating interference effects within a telecommunication network (100) comprising at least a first base station (BS1) and a second base station (BS2), which serve in a cooperative manner a first user equipment (UE1) and a second user equipment (UE2) by using time division duplex. The method is applied in an operational state, in which the first base station (BS1) is in a downlink mode and the second base station (BS2) is in an uplink mode. The method comprises (a) determining at least one of a first channel state information between the first base station (BS1) and the second base station (BS2) and a second channel state information between the first user equipment (UE1) and the second user equipment (UE2), (b) encoding data signals based on the first and/or the second channel state information, and (c) transmitting the encoded data signals by the first base station (BS1) and/or by the second base station (BS2). It is further described a telecommunication network, a program element and a computer readable medium, which are adapted to carry out or control the described method.