Base Station Channel Selection Using Sorted CCA
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Solution Overview
Problem
Conventional channel selection methods in wireless network systems using Licensed-Assisted Access (LAA) and Licensed-Shared Access (LSA) technologies face delays and the hidden terminal problem when multiple base stations instruct UEs to use the same band, leading to inefficiencies in data transmission.
Innovation Solution
A base station and UE system that configures Primary and Secondary Component Carriers, where the base station receives and sorts channel status parameters to determine candidate SCCs, performs Clear Channel Assessment (CCA) to identify available SCCs, and transmits reservation signals to allocate resources, avoiding the hidden terminal problem and minimizing data transmission delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the base station performs CCA on all SCCs without sorting, then the channel assessment is simple, but the data transmission delay increases because the base station may perform CCA on unavailable channels first
Solution Approach 1:
The base station performs preliminary sorting of SCCs based on channel status parameters before performing CCA. This preliminary action arranges SCCs in an optimal sequence, ensuring that channels with better status are assessed first, thereby reducing the expected number of CCA operations needed to find an available channel and minimizing data transmission delay.
Solution Approach 2:
The channel assessment process becomes dynamic by adapting the CCA sequence based on real-time channel status parameters. Instead of a fixed assessment order, the system dynamically adjusts which SCC to assess next based on the current status of each channel, optimizing the assessment path to minimize delay while accounting for changing channel conditions.
2Reliability
If multiple base stations independently perform CCA and allocate the same SCC, then each base station operates autonomously, but the hidden terminal problem occurs causing resource conflicts
Solution Approach 1:
The base station receives feedback information from UEs about the channel status of SCCs. This feedback mechanism provides the base station with real-time information about channel availability and usage, enabling it to make more reliable allocation decisions and avoid the hidden terminal problem by being aware of actual channel conditions rather than making independent assumptions.
Solution Approach 2:
The channel status parameters act as an intermediary information source that mediates between multiple base stations' allocation decisions. By basing allocation on this shared information about actual channel status, the system reduces the likelihood of conflicting allocations while maintaining the autonomy of individual base station operations.
3Ease of operation
If the base station uses fixed-length frames for CCA (FBE), then the frame structure is simple, but the data transmission delay increases when the base station misses the CCA time interval
Solution Approach 1:
The base station performs preliminary sorting of SCCs before the CCA process begins. This preliminary arrangement ensures that when CCA opportunities arise, the base station is ready with an optimized assessment sequence, allowing it to maximize the utility of each CCA interval and reduce the impact of missing intervals on overall transmission delay.
Solution Approach 2:
The system introduces dynamic elements into the otherwise fixed frame structure by allowing the CCA assessment sequence to adapt based on channel status. This dynamic sequencing within the fixed frame framework allows the base station to optimize its use of available CCA opportunities while maintaining the simplicity of the overall frame structure.
Data Source
AI summary
A base station, user equipment, and channel selection method are provided. The base station can configure a Primary Component Carrier (PCC) and a plurality of Secondary Component Carriers (SCCs). The PCC is a Long Term Evolution (LTE) band, while at least one of the SCCs is not an LTE band. The base station receives a plurality of channel status parameters, wherein each of the channel status parameters corresponds to one of the SCCs. The base station sorts the SCCs according to the channel status parameters, determines a subset of the SCCs as at least one candidate SCC according to the channel status parameters, and determines a subset of the at least one candidate SCC as at least one available SCC by performing clear channel assessment for each of the at least one candidate SCC.