LTE Uplink Latency Reduction via Pre-allocated Resource Selection
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Solution Overview
Problem
Current LTE uplink transmission systems experience latency due to the need for communication devices to request and wait for grants from base stations, leading to undesirable delays in data transfer.
Innovation Solution
The method involves acquiring configuration information for Downlink Control Information (DCI) messages to select resource assignments for uplink carrier transmissions, allowing devices to transmit data without waiting for grants by using contention-based resource selection, thereby reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a device requests a grant from a base station to transmit data, then the base station can control resource allocation, but the device experiences latency due to waiting for the grant
Solution Approach 1:
The base station pre-allocates uplink resources to the device before the device needs to transmit data. This preliminary resource assignment eliminates the need for the device to request and wait for a grant, directly reducing transmission latency while maintaining controlled resource allocation through the pre-established assignment
2Speed
If the base station sends frequent grants to reduce latency, then transmission speed improves, but system complexity and signaling overhead increase
Solution Approach 1:
A single uplink grant message is designed to simultaneously serve multiple transmission purposes and time instances. The grant structure includes fields that enable it to function as both an immediate transmission authorization and a pre-assignment for future transmissions, reducing the need for multiple separate grant messages and thereby lowering system complexity while maintaining high transmission speed
Data Source
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AI summary
A method and apparatus reduce latency of Long Term Evolution (LTE) uplink transmissions. Configuration information regarding a Downlink Control Information (DCI) message for a Physical Uplink Shared Channel (PUSCH) transmission can be acquired. The DCI message can be received on a Physical Downlink Control Channel (PDCCH) in a first subframe. The DCI message can indicate a plurality of resource assignments in a second subframe for an uplink carrier from which a User Equipment (UE) can select one resource assignment for transmission on the uplink carrier. The DCI message can be Cyclic Redundancy Check (CRC) scrambled by a Radio Network Temporary Identifier (RNTI) that is indicated via higher layers that are higher than a physical layer. A resource assignment can be selected from the plurality of resource assignments using a selection criterion. A data packet can be transmitted on the PUSCH in a resource of the selected resource assignment in the second subframe on the uplink carrier.