LTE Timing Advance Method for Large Cell Radius
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Solution Overview
Problem
The existing LTE system cannot support cell radii larger than 100km, as it requires modifications to the random access sub-frame that increase PRACH channel occupancy, reducing system performance and being unsuitable for TDD LTE systems.
Innovation Solution
A method for determining Timing Advance (TA) in LTE systems with large cell radius coverage, where user equipment calculates a timing adjustment set based on received TA and cell radius, allowing for uplink transmission timing adjustments to support larger cell radii without altering the protocol, suitable for both TDD and FDD LTE systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the Format of the random access sub-frame is modified to increase the time-domain lengths of the CP part, the preamble sequence part and the GT part, then the cell radius can be increased, but the PRACH channel occupies more physical resources, reducing the performance of the service channel
Solution Approach 1:
The patent applies dynamics by making the timing advance value adjustable and adaptive rather than fixed. The base station dynamically determines a timing advance value based on the actual cell radius, and the UE adjusts its uplink transmission timing accordingly. This dynamic adjustment mechanism allows the system to support variable cell radii without requiring permanent modifications to the random access sub-frame structure, thus avoiding increased PRACH resource occupancy while still achieving extended cell radius support.
Solution Approach 2:
The patent changes the parameter of timing advance value to adapt to different cell radii. Instead of modifying the physical structure of the random access sub-frame, the system adjusts the timing advance parameter dynamically. The base station calculates an appropriate timing advance value based on the cell radius, and this parameter is conveyed to the UE to adjust its transmission timing. This parameter-based solution allows flexible adaptation to different cell sizes without increasing resource consumption.
2Length of stationary object
If the Format of the random access sub-frame is modified to increase the time-domain lengths, then the cell radius can be increased, but the TDD LTE system cannot support the time-domain length of a larger random access sub-frame under the existing frame format
Solution Approach 1:
The patent resolves the frame format compatibility issue by changing the timing advance parameter rather than modifying the frame structure. The base station determines a timing advance value that compensates for the propagation delay in large cell radii, and the UE applies this parameter adjustment to its uplink transmissions. This approach maintains the existing TDD frame format structure while achieving support for larger cell radii through parameter adaptation, thus preserving frame format compatibility.
Solution Approach 2:
The patent applies dynamics by implementing a dynamic timing advance adjustment mechanism that adapts to different cell configurations. The base station calculates the appropriate timing advance value based on the actual cell radius and conveys it to the UE. This dynamic parameter adjustment allows the system to support variable cell sizes without requiring different frame formats, making the solution universally applicable to both small and large cell scenarios in TDD LTE systems.
3Device complexity
If the existing LTE protocol is used, then the implementation is simple, but the maximum cell radius supported is limited to 100km
Solution Approach 1:
The patent applies self-service by enabling the base station to autonomously determine and calculate the appropriate timing advance value based on the actual cell radius. The base station performs the calculation and conveys the timing advance parameter to the UE without requiring complex protocol modifications or additional network infrastructure. This self-service approach maintains implementation simplicity while achieving extended cell radius support through intelligent parameter determination.
Solution Approach 2:
The patent resolves the limitation by changing the timing advance parameter dynamically rather than modifying the protocol structure. The base station calculates an appropriate timing advance value based on the cell radius and conveys it to the UE. This parameter-based solution allows the system to support cell radii larger than 100km while maintaining the simplicity of the existing LTE protocol implementation, avoiding complex protocol changes.
Data Source
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AI summary
The embodiment of the present document provides a method, user equipment and base station for determining a timing advance, which can support a larger cell radius without changing the protocol, the required device complexity is low, and with the UE side transmitting msg3 by using different TA adjustments to obtain a correct timing deviation value, the access delay of the PRACH is minimized, and the overhead of the PRACH sub-frame will not be increased, which can prevent the performance of the system from deterioration, and it can be applied to TDD and FDD LTE systems simultaneously.