Grantless Uplink Beam Resource Mapping in mmW Systems
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Solution Overview
Problem
In wireless communication systems, especially in millimeter wave (mmW) frequency bands, grantless transmissions on uplink subframes face challenges due to increased signal attenuation and the need for efficient beam management, particularly in unlicensed radio frequency spectrum bands where resources may not be consistently available.
Innovation Solution
A method for wireless communication that involves receiving timing information and a time-frequency resource configuration for uplink subframes, allowing UEs to select appropriate time-frequency resources based on their transmit beams and corresponding receive beams, and performing Listen Before Talk (LBT) procedures to ensure availability, thereby optimizing grantless transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam sweeping is used to cover the entire cell with narrow beams in mmW frequency bands, then signal attenuation is overcome and communication reliability is improved, but device complexity and resource management difficulty increase
Solution Approach 1:
The patent segments the beam management process by associating specific PRACH resources with specific downlink beams. Each UE can independently select resources corresponding to its preferred beam without coordinating with other UEs, dividing the complex beam management task into simpler, beam-specific resource allocations.
Solution Approach 2:
The patent performs preliminary beam association by pre-configuring PRACH resources for each downlink beam before UEs need to access the network. This preliminary mapping allows UEs to directly use pre-assigned resources based on their beam measurements, eliminating the need for complex real-time beam management during access.
2Reliability
If dedicated PRACH resources are allocated for each downlink beam, then beam-specific access is improved and interference is reduced, but resource allocation complexity and loss of time for configuration increase
Solution Approach 1:
The patent performs preliminary beam association by pre-configuring PRACH resources for each downlink beam before UEs need to access the network. This preliminary mapping allows UEs to directly use pre-assigned resources based on their beam measurements, eliminating the need for complex real-time beam management during access.
3Productivity
If grantless transmissions are used in unlicensed bands, then resource allocation efficiency is improved and latency is reduced, but interference management difficulty and signal reliability worsen
Solution Approach 1:
The patent applies local quality by allowing UEs to perform grantless transmissions on specific time-frequency resources that are locally optimized for their preferred beam. Each UE selects resources corresponding to its best beam direction, ensuring that transmissions occur in spatial directions with the best channel conditions, thereby maintaining reliability while enabling efficient grantless access.
Data Source
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AI summary
A method for wireless communication at a user equipment (UE) includes receiving timing information and a time-frequency resource configuration for an uplink subframe; selecting at least a first set of time-frequency resources of the uplink subframe on which to transmit; and transmitting a grantless transmission on at least the first set of timefrequency resources. The time-frequency resource configuration identifies a correspondence between at least one receive beam in a set of one or more receive beams and at least one set of time-frequency resources in one or more sets of time-frequency resources of the uplink subframe. The first set of time-frequency resources is selected based at least in part on a transmit beam of the UE, a correspondence of the transmit beam to a receive beam in the set of one or more receive beams, and a correspondence of the receive beam to the selected first set of time-frequency resources.