Communication Node Contention Window Adaptation for Unlicensed Bands
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Solution Overview
Problem
The existing methods for changing the size of the contention window in unlicensed bands for LTE (or LTE-A) services do not consider the status of the unlicensed band, leading to inefficiencies and potential collisions.
Innovation Solution
The contention window size is dynamically adjusted based on the occupation state of the unlicensed band, hybrid automatic repeat request (HARQ) responses, and collision-aware information to optimize communication performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the contention window size is changed statically or without considering unlicensed band status, then the procedure is simple, but the communication performance deteriorates due to inefficiencies and collisions
Solution Approach 1:
The contention window size is changed dynamically based on the occupation status of the unlicensed band. The base station monitors whether the unlicensed band is occupied by other communication nodes and adjusts the contention window size accordingly, transforming the static parameter into a dynamic one that adapts to changing channel conditions.
Solution Approach 2:
The base station receives feedback information about the occupation status of the unlicensed band from other communication nodes or through sensing mechanisms. This feedback is used to adjust the contention window size, creating a closed-loop control system that improves communication performance by responding to actual channel conditions.
2Loss of time
If the contention window size is adjusted without considering unlicensed band occupation status, then the adjustment is simple, but transmission latency increases due to unnecessary backoff operations
Solution Approach 1:
The base station performs preliminary sensing or receives advance information about the occupation status of the unlicensed band before attempting transmission. This preliminary action allows the base station to prepare appropriate contention window sizes in advance, avoiding unnecessary backoff operations and reducing transmission latency.
Solution Approach 2:
The contention window size parameter is changed based on the occupation status of the unlicensed band. When the band is determined to be free, a smaller contention window is used to reduce waiting time, while when occupation is detected, a larger window is used to avoid collisions, thereby optimizing transmission latency under different conditions.
3Quantity of substance
If LTE services are provided through unlicensed band, then licensed band resources are conserved, but coexistence problems with WLAN nodes arise
Solution Approach 1:
The base station uses the occupation status information of the unlicensed band, which indicates the presence of WLAN or other communication nodes, to adjust the contention window size. By converting the potentially harmful interference from coexisting nodes into useful information for parameter adjustment, the system improves its ability to coexist with WLAN nodes while conserving licensed band resources.
Data Source
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AI summary
An operating method of a communication node in a network supporting licensed and unlicensed bands is disclosed. An operation method of a base station comprises the steps of: transmitting a PDSCH to a UE in an unlicensed band; receiving an HARQ response to the PDSCH from the UE; and determining a size of a CW on the basis of a proportion of NACKs in HARQ responses. Therefore, a performance of a communication network can be improved.