Terminal Device Preamble Transmission in TDD NB-IoT
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Solution Overview
Problem
In TDD NB-IoT, terminal devices face challenges in sending preambles due to limited continuous uplink resources, preventing them from accessing base stations effectively.
Innovation Solution
The method involves a terminal device sending M symbol groups in K uplink subframe sets, with at least one consecutive uplink subframe in each set and spaced by downlink subframes, and frequency hopping between adjacent symbol groups with opposite directions, allowing for discontinuous uplink resource utilization and improved network synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a terminal device sends a preamble with time length of 5.6 ms or 6.4 ms in TDD NB-IoT, then the preamble transmission can be completed as in FDD NB-IoT, but the continuous uplink resources available in TDD are insufficient (at most three consecutive subframes with total time length of 3 ms)
Solution Approach 1:
The patent segments the preamble transmission into multiple parts distributed across different uplink subframe sets. Instead of transmitting the entire preamble in one continuous time slot, the terminal device transmits multiple symbol groups in separate uplink subframe sets that are interspersed with downlink subframes, effectively dividing the transmission task to fit within TDD resource constraints.
Solution Approach 2:
The patent employs periodic transmission of symbol groups across multiple uplink subframe sets. The terminal device transmits symbol groups at periodic intervals separated by downlink subframes, creating a periodic action pattern that utilizes available TDD uplink resources efficiently while achieving the required total transmission duration.
2Reliability
If frequency hopping is applied between adjacent symbol groups, then resource utilization and reliability are improved, but phase impact on network device estimation may occur
Solution Approach 1:
The patent implements frequency hopping in a periodic manner between adjacent symbol groups. The frequency hops follow a periodic pattern that allows the network device to predict and compensate for phase changes, thereby maintaining estimation accuracy while benefiting from the diversity and reliability improvements provided by frequency hopping.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances resource utilization and resolves the issue of preamble transmission in TDD NB-IoT, enabling terminal devices to access base stations and improving timing advance estimation reliability.
Implementation Method 1
N times of frequency hopping exist in the M symbol groups, each of the N times of frequency hopping is frequency hopping between adjacent symbol groups in the M symbol groups, and frequency hopping directions of at least two of the N times of frequency hopping are opposite
Data Source
AI summary
A communication method and apparatus are disclosed. The method includes: determining, by a terminal device, a preamble, where the preamble includes M symbol groups, where M is a positive integer greater than 1; and sending, by the terminal device, the M symbol groups in K uplink subframe sets, where any uplink subframe set in the K uplink subframe sets includes at least one consecutive uplink subframes, any two uplink subframe sets in the K uplink subframe sets are spaced by at least one downlink subframe, and in each of the K uplink subframe sets at least one symbol group can be sent, where K is a positive integer greater than 1, and K is less than or equal to M; and N times of frequency hopping exist in the M symbol groups, each of the N times of frequency hopping is frequency hopping between adjacent symbol groups in the M symbol groups, and frequency hopping directions of at least two of the N times of frequency hopping are opposite, where N is less than M.