Scheduling Shared Spectrum via Licensed Band Feedback
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Solution Overview
Problem
Wireless communication systems face challenges in scheduling downlink and uplink data transmissions in shared radio frequency spectrum bands due to differences in channel acquisition and grant procedures between licensed and unlicensed or shared radio frequency spectrum networks, leading to inefficiencies in channel utilization and data transmission.
Innovation Solution
The implementation of a Long Term Evolution (LTE) Controlled Wi-Fi (LTE-CW) network environment, where user equipment (UE) performs clear channel assessment (CCA) on shared frequency spectrum bands and reports channel readiness information via an LTE link, allowing the base station to schedule data transmissions and manage channel availability effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If channel readiness information is transmitted via the shared radio frequency spectrum band, then channel utilization is improved, but transmission reliability deteriorates due to potential interference and channel unavailability
Solution Approach 1:
The patent introduces a licensed radio frequency spectrum band as an intermediary channel for transmitting channel readiness information and scheduling data. This mediator ensures reliable transmission by using a dedicated licensed band that is not subject to the same interference and contention issues as the shared unlicensed band, thereby resolving the contradiction between utilizing the shared band and ensuring transmission reliability
Solution Approach 2:
The patent segments the communication functions by separating the data transmission function (using shared band for high throughput) from the control information transmission function (using licensed band for reliability). Channel readiness information and scheduling grants are transmitted on the licensed band while actual data transmissions occur on the shared band, allowing each to optimize for its specific requirement
2Reliability
If clear channel assessment procedures are implemented in shared spectrum bands, then channel availability is improved, but transmission delay increases due to additional assessment steps
Solution Approach 1:
The patent implements preliminary channel readiness assessment by having the wireless communication device perform clear channel assessment (CCA) procedures in advance and report channel readiness information to the base station via the licensed band. This preliminary action allows the base station to schedule transmissions without requiring real-time CCA, thereby ensuring channel availability while minimizing transmission delay
Solution Approach 2:
The patent establishes a feedback mechanism where the wireless communication device continuously monitors channel conditions in the shared band and reports readiness status to the base station. This feedback loop enables the base station to make informed scheduling decisions based on current channel conditions without requiring the device to perform CCA at the moment of transmission, reducing delay while maintaining reliability
3Reliability
If separate licensed and shared spectrum bands are used, then transmission reliability is improved, but system complexity increases due to multi-band coordination
Solution Approach 1:
The patent applies multi-functionality by using the licensed band for multiple control functions including transmitting channel readiness information, sending scheduling grants, and coordinating shared band transmissions. This consolidates control plane functions on the reliable licensed band while keeping the shared band for data plane operations, improving reliability without proportionally increasing complexity through functional distribution
Data Source
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AI summary
Methods, systems, and devices are described for techniques for downlink (DL) scheduling and uplink (UL) scheduling in a shared radio frequency (RF )spectrum band. In some aspects, a wireless communication device may receive an UL data transmission grant associated with a channel of shared RF spectrum band. The wireless communication device may perform a channel readiness procedure associated with the channel. The wireless communication device may also transmit channel readiness information based at least in part on the channel readiness procedure to a base station. The channel readiness information may be transmitted via an uplink channel of a licensed RF spectrum band different from the shared RF band. In other aspects, a base station may schedule a data transmission on one or more channels of a shared RF spectrum band. The base station may transmit a data transmission grant for the scheduled data transmission to a wireless communication device.