Extending LTE Cell Coverage via Segmented Random Access Preamble
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Solution Overview
Problem
The maximum coverage radius of a single-station cell in TD-LTE systems is limited to 100 kilometres, which is insufficient for special scenarios requiring larger coverage areas, such as shipping lines or sea surfaces.
Innovation Solution
The method involves determining and extending the guard time (GT) in the random access preamble based on the required cell coverage radius, adjusting the allocation of uplink/downlink time slot resources, and modifying the radio frame structure to ensure sufficient resources for transmitting the extended preamble, thereby increasing the coverage radius beyond 100 kilometres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the guard time (GT) in the random access preamble is extended to increase coverage radius, then the coverage radius is improved, but the radio frame structure becomes more complex and resource allocation becomes more difficult
Solution Approach 1:
The patent divides the extended random access preamble into multiple parts that can be transmitted across different subframes. The preamble is segmented such that part of it is transmitted in the special subframe and the remaining part in regular uplink subframes, making the extended transmission manageable and structured.
Solution Approach 2:
The patent introduces dynamic configuration of the random access preamble transmission, where the network can flexibly allocate resources and adjust the transmission parameters based on the actual coverage requirements. The guard time extension is dynamically configured rather than fixed, allowing adaptation to different deployment scenarios.
2Length of stationary object
If the guard period (GP) is extended to support larger cell radius, then the coverage area is improved, but the uplink/downlink time slot ratio becomes more constrained
Solution Approach 1:
The patent segments the random access preamble transmission across multiple time slots, with portions transmitted in special subframes and portions in regular uplink subframes. This segmentation allows the system to maintain flexible uplink/downlink configurations while supporting extended coverage.
Solution Approach 2:
The patent makes the random access preamble transmission multi-functional by allowing it to span both special subframes and regular uplink subframes. This universal approach enables the same preamble transmission mechanism to work for both normal coverage and extended coverage scenarios without requiring separate dedicated resources.
3Length of stationary object
If the random access preamble length is increased to extend coverage, then the coverage radius is improved, but the transmission time and resource occupation are increased
Solution Approach 1:
The extended random access preamble is segmented and transmitted across multiple subframes rather than as a single continuous transmission. This segmentation allows the transmission to be distributed over time, reducing the impact on any single time slot while achieving the extended coverage goal.
Solution Approach 2:
The patent utilizes the periodic structure of TD-LTE radio frames, where the extended preamble transmission is aligned with the periodic uplink subframe structure. This periodic action allows the extended transmission to integrate smoothly with the existing frame structure, minimizing disruption to overall system timing.
Data Source
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AI summary
Provided are a method and device for processing a random access preamble. The method includes: determining, according to a coverage radius of a cell, a guard time (GT) that is needed when a user equipment (UE) communicates with a base station, wherein the coverage radius of the cell is greater than 100 kilometres; and, determining, according to the GT, a random access preamble transmitted by the UE to the base station, wherein the random access preamble is transmitted on a special subframe and at least one regular subframe of a radio frame when the UE communicates with the base station. The solution solves the problem that the maximum coverage range of a single-station cell cannot satisfy a need in a special scenario, further increases the coverage radius of the single-station cell, and satisfies the need in the special scenario for an extra-large radius in cell coverage range.