RRU Channel Contention Coordination in Distributed Wireless Systems

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Solution Overview

Problem

In wireless communications, particularly in the 3GPP's Licensed-Assisted Access technology, there is a need for a novel channel contention method that meets high real-time performance requirements in an RRU-BBU distributed architecture, as existing methods struggle to coordinate channel access efficiently to avoid collisions and ensure real-time data transmission.

Innovation Solution

The method involves the RRU contending for a target channel, sending carrier status information to the BBU, and coordinating with other RRUs through an RHUB to ensure simultaneous transmission without interference, by using CCA time periods and cooperation indication information to synchronize channel contention and occupation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the BBU allocates channels to RRUs in a distributed architecture, then channel management flexibility is improved, but channel contention coordination becomes more complex and real-time performance deteriorates

Engineering Contradiction:
Improvechannel management flexibilityVSAvoidchannel contention coordination complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the channel contention process into two parts: LBT detection performed independently by each RRU, and backoff counter coordination performed by the BBU. This segmentation allows RRUs to autonomously detect channel status in real-time while the BBU manages the contention logic, reducing coordination complexity and improving real-time performance in distributed architectures.

Inventive Principle:
Principle #1Segmentation

2Speed

If multiple RRUs contend for channels independently, then real-time transmission responsiveness is improved, but channel collision probability increases

Engineering Contradiction:
Improvetransmission responsivenessVSAvoidchannel collision avoidance
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where RRUs report their LBT detection results and backoff counter status to the BBU. The BBU uses this feedback information to coordinate backoff counters across multiple RRUs, ensuring they select different channels or transmit at different times, thereby maintaining real-time responsiveness while avoiding collisions through informed coordination.

Inventive Principle:
Principle #23Feedback

3Reliability

If the BBU coordinates backoff counters for all RRUs, then channel collision is avoided, but communication overhead and latency increase

Engineering Contradiction:
Improvechannel collision avoidanceVSAvoidcoordination latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having RRUs perform LBT detection and determine channel status before the BBU performs backoff counter coordination. This preliminary local detection reduces the amount of information that needs to be coordinated centrally, allowing the BBU to make faster coordination decisions based on pre-processed channel status reports, thereby reducing overall coordination latency while maintaining collision avoidance.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3397016B1Channel contention method and apparatus
Publication Date: 2021.08.04 HUAWEI TECH CO LTD
  • EP3397016B1 patent drawingFigure 1~2
  • EP3397016B1 patent drawingFigure 3~4
  • EP3397016B1 patent drawingFigure 5A

AI summary

The present invention provides a channel contention method and an apparatus. The method includes: contending, by an RRU, for a target channel; and sending carrier status information to a BBU, where the carrier status information is used to indicate a channel contention result of the RRU. The RRU contends for a channel and can occupy the channel after the contention is successful, and then notifies the BBU of a result of the contention by using the carrier status information, thereby meeting a requirement on real-time performance of channel contention in a distributed scenario.