Single-Tone Random Access Preamble Transmission for IoT Coverage
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Solution Overview
Problem
The existing 3GPP LTE system is not cost-effective for IoT communications, particularly in challenging environments, as it requires high bandwidth and is not optimized for single-tone transmission methods, which are not currently supported, limiting its efficiency in areas with poor channel conditions.
Innovation Solution
The proposal involves designing a method for single-tone transmission of the random access preamble in LTE systems, using a frequency resource unit with specific sub-symbol configurations and guard times to enhance signal arrival time estimation and coverage, allowing for efficient communication in poor channel conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LTE system uses standard multi-tone random access preamble transmission, then the system maintains compatibility with existing 3GPP standards, but it cannot achieve cost reduction and improved coverage for IoT devices in poor channel conditions
Solution Approach 1:
The patent changes the transmission parameter from multi-tone to single-tone by configuring the random access preamble to occupy only one subcarrier instead of multiple subcarriers. This parameter change enables power concentration on a single frequency resource, improving coverage and reliability for IoT devices while maintaining standard compatibility through proper signaling.
2Ease of manufacture
If the system reduces bandwidth to reduce costs, then IoT devices can operate at lower prices, but communication in poor channel environments becomes difficult
Solution Approach 1:
The patent changes the power distribution parameter from distributed across multiple resource blocks to concentrated on a single resource element. This parameter change allows IoT devices to achieve better coverage and reliability in poor channel conditions while operating in reduced bandwidth, thus maintaining cost-effectiveness.
Solution Approach 2:
The patent employs repeated transmission of the random access preamble multiple times within the same or different subframes. This periodic action increases the probability of successful detection by the base station in poor channel conditions, compensating for the reduced bandwidth and single-tone transmission limitations.
3Reliability
If power boosting is applied by concentrating power on one RE in an RB, then coverage is improved for single-tone transmission, but the method is not supported by current 3GPP standards
Solution Approach 1:
The patent changes the resource allocation parameter from the standard 12 subcarriers per RB to a single subcarrier configuration for random access preamble transmission. This parameter change enables power boosting and coverage extension while maintaining compatibility with 3GPP standards through appropriate higher-layer signaling and configuration.
Data Source
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AI summary
Disclosed is a method for a wireless device for transmitting a random-access preamble. The method may comprise the steps of: generating a sequence of a random-access preamble; and mapping the sequence of a random-access preamble to one sub-carrier wave from among 12 sub-carrier waves of a frequency domain. The mapping step may comprise the step for carrying out a first hop between a plurality of sub-regions. Each sub-region may comprise a previously set number of sub-carrier waves. The mapping step may additionally comprise the step for carrying out a second hop from among the sub-carrier waves within any one sub-region.