Carrier Aggregation Transceiver Latency via Direct SPI Link

Solution Overview

Problem

In LTE-Advanced Carrier Aggregation scenarios, excessive latency in transferring Rank Indicator/Precoding Type Indicator (RI/PTI) bits between transceivers can lead to connection failures due to the need for communication with a common MAC scheduler, which is not efficient for decoding subsequent subframes with Channel Quality Indicator/Precoding Matrix Indicator (CQI/PMI) bits.

Innovation Solution

Implementing a dedicated Serial Peripheral Interface (SPI) link for direct interconnection between transceivers in a daisy-chain fashion, along with a firmware-defined RI/PTI controller module on each transceiver to control uplink transmissions without involving a common scheduler, ensuring rapid transfer of decoded RI/PTI bits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a common MAC scheduler is used to coordinate transceivers in carrier aggregation, then system management is simplified, but latency in transferring RI/PTI bits between transceivers increases causing connection failures

Engineering Contradiction:

Improvesystem management complexityVSAvoidRI/PTI transfer latency

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The patent segments the carrier aggregation system into independent transceiver units, each capable of autonomous operation with local RI/PTI buffering. This segmentation eliminates the single-point bottleneck of the common MAC scheduler while maintaining coordinated multi-carrier operation through distributed intelligence.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary RI/PTI buffer mechanism that sits between transceivers and the MAC scheduler, allowing RI/PTI information to be pre-transferred and cached before being needed for CQI/PMI decoding. This intermediary buffering decouples the timing requirements from the scheduling complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If transceivers communicate through a common MAC scheduler, then resource allocation is centralized, but decoding of subsequent subframes with CQI/PMI bits fails due to excessive latency

Engineering Contradiction:

Improveresource allocation centralizationVSAvoidCQI/PMI decoding success

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent implements preliminary action by transferring and buffering RI/PTI bits in advance of when they are needed for CQI/PMI decoding. The RI/PTI buffer pre-stores this critical information at each transceiver, ensuring that when CQI/PMI subframes arrive, the necessary RI/PTI context is already available locally for immediate decoding without scheduler-mediated delays.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If RI/PTI and CQI/PMI are reported on separate Component Carriers in consecutive subframes, then carrier aggregation performance is maximized, but connection failures occur due to latency in RI/PTI transfer

Engineering Contradiction:

Improvecarrier aggregation data rateVSAvoidconnection stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the carrier aggregation system into independent transceiver units, each capable of autonomous operation with local RI/PTI buffering. This segmentation eliminates the single-point bottleneck of the common MAC scheduler while maintaining coordinated multi-carrier operation through distributed intelligence.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary RI/PTI buffer mechanism that sits between transceivers and the MAC scheduler, allowing RI/PTI information to be pre-transferred and cached before being needed for CQI/PMI decoding. This intermediary buffering decouples the timing requirements from the scheduling complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10182464B2Method, device and test setup for implementing carrier aggregation

Publication Date: 2019.01.15 KEYSIGHT TECH SINGAPORE (SALES) PTE LTD

AI summary

There is provided a method of implementing carrier aggregation on a first transceiver. The method comprises receiving and decoding, during a first subframe, channel quality information from user equipment and transferring, before the expiry of a second subframe immediately following the first subframe, the decoded channel quality information over a direct physical link to a second transceiver, for use in decoding further channel quality information from the user equipment.