NB-IoT Random Access Preamble Transmission with Periodic Gaps
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Solution Overview
Problem
Current wireless communication systems, particularly those supporting NarrowBand-Internet of Things (NB-IoT), face challenges in maintaining performance and synchronization due to repetitive transmission of random access preambles, leading to potential resource shortages and increased latency.
Innovation Solution
A method for transmitting and receiving a random access preamble in a wireless communication system using a specific preamble structure with a subcarrier spacing of 1.25 kHz, where the preamble is repeated 16 times with a predetermined gap inserted after each transmission, allowing for effective cell range extension and preventing performance deterioration and synchronization deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If random access preamble is repeatedly transmitted to extend cell range, then coverage area is improved, but synchronization deviation and performance deterioration occur
Solution Approach 1:
The patent implements periodic interruption of the random access preamble transmission by inserting a gap after a predetermined number of repetitions. This periodic action allows the system to maintain synchronization by stopping transmissions at regular intervals, preventing the accumulation of timing errors while still achieving cell range extension through the repeated transmissions before the gap.
2Area of stationary object
If random access preamble is repeatedly transmitted to improve coverage, then transmission reach is improved, but resource consumption increases
Solution Approach 1:
By periodically interrupting the repeated transmissions with gaps, the system optimizes resource usage. Instead of continuous transmissions that would consume excessive resources, the periodic interruption allows the system to achieve coverage extension with a controlled number of repetitions, thereby reducing overall resource consumption while maintaining effective cell range.
3Reliability
If gap is inserted after repeated transmissions, then synchronization is maintained, but transmission latency increases
Solution Approach 1:
The patent applies partial action by inserting the gap only after a predetermined number of repetitions (not after every transmission). This partial interruption is sufficient to maintain synchronization accuracy while minimizing the impact on overall transmission latency. The gap is strategically placed only when needed to prevent synchronization deviation, rather than continuously.
4Area of stationary object
If number of repetitions is increased to extend cell range, then coverage area is improved, but performance deterioration increases
Solution Approach 1:
The periodic interruption with gaps prevents the degradation of signal quality that would occur with excessive continuous repetitions. By stopping transmissions periodically, the system allows for timing realignment and prevents the accumulation of errors, thereby maintaining signal quality even as the number of repetitions increases to extend cell range.
Data Source
AI summary
Provided is a method for transmitting a random access preamble by a user equipment (UE) in a wireless communication system supporting a narrow band-Internet of things (NB-IoT). Specifically, the UE transmits the random access preamble to an eNB in a subcarrier allocated by the eNB according to a specific preamble structure and receives a random access response message from the eNB in response to the random access preamble. In this case, the random access preamble is repeatedly transmitted 16 times during a predetermined duration and then, a gap is inserted for a predetermined time and the predetermined duration is determined by multiplying a transmission duration in which the random access preamble is transmitted by the number of repeated transmission times.