Dynamic Timing Advance Adjustment for 5G Uplink Latency
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Solution Overview
Problem
Conventional LTE systems face inefficiencies in timing advance, leading to delayed uplink data transmission and HARQ ACK/NACK timing, especially with shorter TTI lengths or larger timing advance values, which can result in incomplete or delayed data transmission from terminals to base stations.
Innovation Solution
The method involves determining and adjusting the timing advance (TA) value for terminals, allowing for flexible TA threshold settings to accommodate shorter TTI lengths and larger TA values, enabling efficient uplink data transmission and HARQ ACK/NACK timing by distinguishing between different TA thresholds and adjusting transmission types accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the terminal uses a fixed timing advance value for uplink transmission, then the transmission timing is simplified and easier to manage, but the transmission may be delayed or incomplete when larger TA values are required for longer distances
Solution Approach 1:
The patent implements dynamic timing advance adjustment by allowing the terminal to determine TA values dynamically based on the actual distance to the base station rather than using a fixed predetermined value. The terminal calculates the TA value as twice the propagation delay (TA = 2 × propagation delay) to compensate for round-trip transmission time, ensuring that uplink transmissions from terminals at different distances arrive at the base station at the correct timing.
2Loss of time
If the terminal processes signals faster with shorter processing time, then the transmission latency is reduced, but the terminal may not have sufficient time to prepare signals when large TA values are involved
Solution Approach 1:
The patent changes the parameter of processing time requirements by introducing flexible timing relationships between downlink reception and uplink transmission. Instead of using fixed processing time assumptions, the system allows the terminal to determine appropriate processing durations based on the calculated TA value and actual distance, enabling faster processing when TA is small while ensuring sufficient processing time when TA is large.
3Productivity
If the system uses conventional fixed TTI lengths, then the system operation is simpler and more predictable, but the transmission efficiency is reduced when shorter TTIs are needed for low latency applications
Solution Approach 1:
The patent introduces dynamic TTI length adjustment where the terminal can operate with different TTI durations (e.g., 0.5ms, 1ms, 2ms) based on service requirements and distance conditions. The system dynamically selects appropriate TTI lengths and corresponding TA values, allowing short TTIs for low-latency applications while maintaining longer TTIs for other scenarios, thus improving transmission efficiency without requiring completely complex system operation.
4Reliability
If the terminal assumes a maximum TA value for processing, then the terminal can prepare signals in advance with sufficient time, but additional processes like cell selection or RACH must be performed when the actual TA exceeds the assumed maximum
Solution Approach 1:
The patent applies preliminary action by having the terminal calculate and determine the appropriate TA value before uplink transmission based on the measured distance to the base station. The terminal uses this predetermined TA value to adjust its transmission timing in advance, ensuring that signals are prepared and transmitted at the correct time without needing to perform additional cell selection or RACH procedures that would be required if the TA exceeded assumed maximum values.
Data Source
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AI summary
The present disclosure relates to a 5G or a pre-5G communication system for supporting higher data transmission rates in a beyond-4G communication system, such as LTE. Particularly, the present disclosure relates to a method for a base station in a wireless communication system, comprising the steps of: transmitting resource information of a scheduling request (SR) for each transmission type, to a terminal accessing the base station; and receiving an SR corresponding to the transmission type of the terminal from the terminal, in response to the transmission of the resource information of the SR.