Unlicensed Band Channel Selection via Autocorrelation
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Solution Overview
Problem
Conventional Licensed-Assisted Access (LAA) systems in unlicensed frequency bands face challenges in coexisting with Wi-Fi technologies, leading to unfair sharing of radio resources, with LAA systems typically receiving a smaller capacity due to contention with Wi-Fi devices using Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocols.
Innovation Solution
A network node analyzes signals across multiple frequency channels without demodulation to estimate load and identify types of wireless communication devices, selecting a channel for scheduling communications based on both load and device types, using autocorrelation techniques to differentiate between 802.11ax and non-802.11ax devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LAA systems use CSMA/CA protocol to contend for channel access in unlicensed bands, then channel access fairness is improved, but capacity and throughput deteriorate due to increased contention with Wi-Fi devices
Solution Approach 1:
The patent changes the channel access mechanism from CSMA/CA (contention-based) to scheduled access (reservation-based). The eNB schedules uplink transmissions by granting specific time-frequency resources to UEs, transforming the access paradigm from random contention to coordinated allocation, thereby improving capacity while maintaining fairness through centralized control
Solution Approach 2:
The patent implements dynamic channel access where the eNB adaptively allocates uplink resources based on current channel conditions and traffic demands. The scheduled uplink allows the network to dynamically adjust resource allocation in response to changing conditions, optimizing capacity while ensuring fair access among users
2Productivity
If LAA systems operate with scheduled uplink only, then capacity is improved, but adaptability to coexist with diverse Wi-Fi variants deteriorates
Solution Approach 1:
The patent segments the uplink transmission into two distinct parts: a scheduled portion for capacity-critical data and a contending portion for Wi-Fi coexistence. This segmentation allows the system to simultaneously optimize for capacity through scheduled access while maintaining adaptability through reserved contending opportunities for Wi-Fi interaction
3Ease of operation
If eNB contends for both downlink and uplink channels, then channel access simplicity is improved, but capacity utilization deteriorates due to dual contention overhead
Solution Approach 1:
The patent makes the eNB's channel access mechanism universal by implementing scheduled access for both downlink and uplink directions. The same scheduling framework controls both transmission directions, eliminating the need for separate contention procedures and thereby improving capacity utilization while maintaining operational simplicity through a unified approach
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables more fair and efficient channel allocation, increasing the probability of accessing channels and reducing collisions, thereby enhancing throughput and capacity utilization in unlicensed frequency bands, especially when coexisting with 802.11ax networks.
Implementation Method 1
for each of the two or more frequency channels, correlating the corresponding received signal with one or more delayed versions of the corresponding received signal to generate one or more autocorrelation results
Data Source
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AI summary
A process for selecting frequency channel(s) used by a network node (20) operating in an unlicensed band is disclosed. To that end, a network node (20) analyzes a signal received for each of multiple frequency channels using autocorrelation techniques, and thus without first demodulating the signals, to determine what types of wireless communication devices (32) are contributing to the load of each frequency channel. The network node (20) then selects one of the frequency channels for scheduling communications in the unlicensed band with a wireless communication device (30), where the selection is responsive not only to the estimated load, but also to the identified types of other wireless communication devices (32).