Remote Unit Selective Non-Distribution of Unlicensed Spectrum Signals

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Solution Overview

Problem

Distributed antenna systems (DAS) face interference issues when using unlicensed spectrum due to the need for mechanisms like 'Listen Before Talk' (LBT), which can significantly lower throughput by forcing the source transceiver to remain silent for long periods, even when only one remote unit is transmitting in unlicensed channels.

Innovation Solution

Implementing a remote unit configuration that monitors unlicensed spectrum activity and selectively disables or disconnects the reception and transmission of communications signals based on activity thresholds or throughput impact, allowing the source transceiver to operate without prolonged silences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If Listen Before Talk (LBT) mechanism is implemented to avoid interference in unlicensed spectrum, then signal interference is reduced, but throughput is significantly lowered due to prolonged transmission silences

Engineering Contradiction:

Improvesignal interferenceVSAvoidthroughput

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent segments the LBT mechanism into two independent parts: the source transceiver performs LBT before transmitting to remote units, while each remote unit independently performs LBT before transmitting to the source transceiver. This segmentation allows each entity to make independent transmission decisions based on local channel conditions, eliminating the system-wide silence problem while maintaining interference avoidance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic transmission behavior where remote units can transmit in unlicensed channels without waiting for source transceiver LBT completion. Each remote unit dynamically adjusts its transmission based on its own LBT outcome, creating a flexible system that adapts to local conditions rather than following a rigid centralized schedule.

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If source transceiver performs LBT before transmitting to remote units, then interference with other unlicensed spectrum users is avoided, but the source transceiver must remain silent for long periods

Engineering Contradiction:

Improveinterference with unlicensed spectrum usersVSAvoidtransmission silence period

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having remote units perform their LBT procedure in advance and cache their transmission decisions. This allows them to transmit immediately when the channel is clear without waiting for the source transceiver's LBT completion, effectively decoupling the timing of LBT operations between different entities in the system.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Each remote unit serves itself by independently performing LBT and making autonomous transmission decisions based on local channel conditions. This self-service approach eliminates the need for the source transceiver to coordinate and control LBT timing for all remote units, allowing parallel and independent LBT operations throughout the system.

Inventive Principle:

Principle #25Self-service

3Reliability

If remote units are configured to monitor and selectively disable unlicensed spectrum transmission, then signal quality is maintained, but device complexity increases

Engineering Contradiction:

Improvesignal qualityVSAvoidremote unit configuration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the operational parameters of remote units by enabling or disabling their ability to transmit and receive unlicensed spectrum signals based on monitored activity levels. When unlicensed activity exceeds a threshold, the remote unit parameter changes from an active state to a disabled state, and vice versa. This parameter-based control simplifies the complexity by using straightforward threshold comparisons rather than complex decision logic.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10764760B2Selective non-distribution of received unlicensed spectrum communication signals by a remote unit(s) into a distributed communications system (DCS)

Publication Date: 2020.09.01 ANI ACQUISITION SUB LLC

AI summary

Selective non-distribution of received unlicensed spectrum communications by a remote unit(s) into a distributed communications system (DCS) is provided. In one aspect, the DCS is configured to receive communications signals in unlicensed spectrum from a source transceiver(s) for communications services. The DCS is configured to distribute the received communications signals in unlicensed spectrum to one or more remote units forming respective remote communications coverage areas. To reduce or avoid signal interference when communication signals in unlicensed spectrum are transmitted into the DCS that is also being used for transmissions by a remote transceiver to a remote unit at the same time, received communications signals by the remote units are monitored for unlicensed spectrum. The remote unit is configured to disable or disconnect the reception and/or transmission of the communications signals in the unlicensed spectrum based on the communication signal activity in the unlicensed spectrum.