UE Precoder Update Timing in Transmit Diversity

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Solution Overview

Problem

In wireless communication systems, particularly in UMTS networks, precoder information applied by User Equipment (UE) at the Transmit Time Interval (TTI) boundary can remain constant for the duration of the TTI, leading to compromised data transmission if a PCI feedback error occurs, as there is no update within the TTI to correct the precoder.

Innovation Solution

Applying precoder information in the second or subsequent slot of the TTI, allowing for the correct precoder to be applied at least during a portion of the TTI, thereby reducing the probability of erroneous precoding over the entire TTI.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If precoder information is applied at the TTI boundary, then the precoder remains constant for the duration of the TTI, but this compromises data transmission reliability if a PCI feedback error occurs

Engineering Contradiction:

Improvedata transmission reliabilityVSAvoidprecoder update timing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The TTI is divided into multiple slots, and precoder information is applied at specific slot boundaries rather than uniformly at the TTI boundary. This segmentation allows the system to update precoders at intermediate points, reducing the impact of feedback errors while maintaining manageable complexity through structured timing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Precoder information is applied in advance at slot boundaries before the TTI ends, allowing the correct precoder to be established earlier in the transmission interval. This preliminary action ensures that even if feedback occurs late, the precoder is already updated and applied correctly for the remaining duration.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If precoder information is updated only at the TTI boundary, then system operation is simplified, but the probability of erroneous precoding over the entire TTI increases

Engineering Contradiction:

Improveprecoding accuracyVSAvoidprecoder update operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

Precoder updates occur periodically at slot boundaries within the TTI rather than only at the TTI boundary. This periodic action at regular intervals maintains operational simplicity through predictable timing while improving precoding accuracy by providing multiple update opportunities throughout the transmission interval.

Inventive Principle:

Principle #19Periodic action

3Measurement precision

If precoder information is applied at every slot boundary, then precoding accuracy is improved, but system complexity and processing overhead increase

Engineering Contradiction:

Improveprecoder application precisionVSAvoidslot boundary processing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Precoder information is applied selectively at specific slot boundaries rather than uniformly at every slot boundary. This local quality approach applies the precoder update only where needed (at slots following feedback reception) rather than everywhere, maintaining high precision where required while reducing overall system complexity.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP2745425B1Method and apparatus for application of precoder information at the UE in closed loop transmit diversity

Publication Date: 2019.01.16 QUALCOMM INC

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AI summary

Apparatus and methods are described herein for applying precoding information updates at a user equipment (UE). The UE receives precoder information from a network component. The UE can them transmit packet data over a transmit time interval (TTI) of tow or more slots using transmit diversity. The UE updates the precoder for transmit diversity with the precoder information in a slot subsequent to the first slot in the TTI. The precoder information is applied to update the precoder at a slot boundary within the TTI.