Configurable Random Access Channel Structure for Extended Wireless Coverage
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Solution Overview
Problem
Conventional wireless communication systems face challenges in extending the range of random access channels beyond 15 km without increasing receiver complexity and incurring excessive overhead, particularly as cell sizes increase, leading to issues with sequence ambiguity and inter-symbol interference.
Innovation Solution
The proposed solution involves configuring random access channel bursts with adjustable cyclic prefix and guard time durations, using Zadoff-Chu sequences, and varying the number of subframes and preamble repetitions based on cell size and frequency band to optimize coverage while minimizing overhead, allowing for extended cell sizes up to 100 km.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the transmission time interval is increased to 2 ms to extend coverage area, then the coverage range is improved, but the overhead for cyclic prefix increases proportionally
Solution Approach 1:
The patent applies dynamics by making the cyclic prefix length configurable and adaptable to different cell sizes. Instead of using a fixed cyclic prefix length that increases proportionally with coverage area, the system dynamically selects appropriate cyclic prefix durations (e.g., 4.68 μs, 16.67 μs, 52.08 μs, or 104.17 μs) based on the specific deployment scenario and cell radius requirements, allowing coverage extension without proportional overhead increase.
Solution Approach 2:
The patent changes parameters by introducing configurable cyclic prefix lengths and guard time durations that can be independently optimized. The system allows modification of key parameters including cyclic prefix length, guard time length, and transmission time interval, enabling the network to select optimal parameter combinations for different coverage scenarios without being constrained by the conventional proportional relationship between coverage area and cyclic prefix overhead.
2Reliability
If the guard time is increased to prevent inter-symbol interference in larger coverage areas, then the reliability is improved, but the transmission efficiency deteriorates
Solution Approach 1:
The patent applies parameter changes by allowing independent configuration of guard time duration based on specific deployment requirements. The system supports multiple guard time lengths (e.g., 16.67 μs, 52.08 μs, 104.17 μs) that can be selected according to cell size and propagation conditions, enabling reliable inter-symbol interference prevention in extended coverage areas while maintaining transmission efficiency through optimized parameter selection rather than uniformly increasing guard time.
3Area of stationary object
If the cyclic prefix length is increased to support larger cell sizes, then the coverage range is extended, but the false alarm probability in detection increases
Solution Approach 1:
The patent applies dynamics by implementing configurable cyclic prefix lengths that can be adapted to different cell sizes and deployment scenarios. The system dynamically selects from multiple cyclic prefix duration options (4.68 μs, 16.67 μs, 52.08 μs, 104.17 μs) based on the specific coverage requirements, allowing extended cell size support while maintaining detection accuracy through optimized cyclic prefix selection rather than uniformly increasing cyclic prefix length.
Solution Approach 2:
The patent applies local quality by allowing different cyclic prefix configurations for different cells or cell sizes within the network. Each cell can be configured with the appropriate cyclic prefix length suited to its specific coverage area and propagation characteristics, enabling accurate preamble detection in each local context while supporting varied cell sizes across the network.
Data Source
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Figure 4A
AI summary
The present invention provides a method involving a configurable random access channel structure. One embodiment of the method includes generating a random access channel burst that includes a cyclic prefix and a selected number of repetitions of a preamble. The number of repetitions is selected based on at least one of a cell radius and a radio transmission frequency. This embodiment of the method also includes transmitting the random access channel burst over an air interface.