Spatial Diversity ARQ in Distributed Wireless Systems

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Solution Overview

Problem

Conventional wireless systems face inefficiencies in retransmissions in distributed wireless systems, where geographically distributed antennas require retransmitting data without optimal spatial diversity, leading to suboptimal decoding success rates and increased latency.

Innovation Solution

The method involves selecting the best antenna processing unit (APU) based on signal quality metrics for initial transmission and sequentially utilizing subsequent APUs with lower metrics for retransmissions, minimizing redundant data transmission over serial links and leveraging spatial diversity to improve decoding success.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional retransmission methods are used in distributed wireless systems, then data can be retransmitted, but spatial diversity is not optimally utilized leading to suboptimal decoding success rates

Engineering Contradiction:

Improvedecoding success rateVSAvoidretransmission efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system dynamically selects which APU performs retransmission based on real-time channel conditions and spatial diversity considerations, rather than using a fixed retransmission mechanism. This dynamic adaptation allows optimal utilization of spatial diversity to improve decoding success while maintaining efficiency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of transmission source by switching between different APUs for retransmission. By varying the transmitting APU based on channel conditions and spatial diversity metrics, the system improves decoding success rates without incurring the penalties of conventional retransmission methods.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If retransmissions are performed in distributed wireless systems, then data reliability improves, but latency increases

Engineering Contradiction:

Improvedata transmission reliabilityVSAvoidtransmission latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-positioning data at multiple APUs before retransmission is needed. When a transmission fails, the retransmission can immediately occur from an alternative APU without waiting for data retrieval, thus improving reliability while minimizing latency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Multiple APUs act as intermediaries that can provide retransmission services. Instead of a single APU handling all retransmissions (which increases latency), the system distributes retransmission capability across multiple APUs, allowing faster response and reduced latency while maintaining reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If data is retransmitted over serial links in distributed wireless systems, then decoding can be attempted again, but the burden on downstream serial links increases

Engineering Contradiction:

Improvedecoding successVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The system applies local quality by allowing different APUs to handle retransmissions based on their local channel conditions and load. This distributes the processing burden locally rather than concentrating it, reducing the overall burden on downstream serial links and associated power consumption while maintaining decoding success.

Inventive Principle:

Principle #3Local quality

4Productivity

If conventional retransmission approaches are used, then data can be resent, but spatial diversity gains are not leveraged

Engineering Contradiction:

Improvetransmission efficiencyVSAvoidspatial diversity utilization

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention introduces a spatial dimension to retransmission by selecting different physical APUs (located at different spatial positions) for retransmission. This leverages spatial diversity across different dimensions, improving transmission efficiency by utilizing the geometric distribution of APUs rather than simply repeating transmissions from the same location.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12113628B2Hybrid automatic repeat request (ARQ) with spatial diversity

Publication Date: 2024.10.08 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A wireless system comprises a controlling node and two or more antenna processing nodes coupled to the controlling node but separated from each other. The controlling node sends (720) a command to a first one of the two or more antenna processing nodes, instructing the first one of the two or more antenna processing nodes to transmit data to a wireless device. This may be preceded by selecting (715) the first one of the antenna processing nodes based on an estimated signal quality metric corresponding to the wireless device for each antenna processing node. In response to a determination by the controlling node that the wireless device has not successfully decoded the data, the controlling node sends (730) a command to a second one of the two or more antenna processing nodes, instructing the second one of the antenna processing nodes to transmit the data to the wireless device.