Scheduling-Free Access Sequence Design for 5G mMTC
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Solution Overview
Problem
Current 5G communication technologies face challenges in supporting massive device connections and low-latency requirements due to limited system access device capacity, time-consuming access processes, and high signaling overhead in mMTC and URLLC scenarios, respectively.
Innovation Solution
A data generation method and device that determine sequences with specific cross-correlation characteristics to facilitate scheduling-free access, reducing collision probability and detection complexity through the use of sequences with controlled cross-correlation properties for efficient data processing and transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If terminal random access and base station scheduling are adopted, then system access control is improved, but access latency increases and signaling overhead increases
Solution Approach 1:
The patent extracts and eliminates the random access procedure and scheduling request process from the conventional communication flow. Terminals directly transmit data on uplink resources without completing the multi-step random access handshake, removing the time-consuming access control overhead while maintaining system functionality through pre-configured resources and grant-free transmission mechanisms.
Solution Approach 2:
The system performs preliminary configuration of uplink resources and terminal parameters before actual data transmission. Base stations pre-allocate time-frequency resources and configure terminal devices with necessary transmission parameters in advance, enabling terminals to immediately transmit data without real-time scheduling requests, thus reducing access latency while maintaining controlled access.
2Productivity
If code division with sequences is adopted for scheduling-free access, then resource reuse is improved, but sequence design complexity increases
Solution Approach 1:
The patent changes the parameters of sequences by applying cyclic shifts to base sequences. Instead of designing completely independent sequences for each terminal, the system generates multiple sequences from a single base sequence by applying different cyclic shift values. This parameter transformation approach enables multiple terminals to have distinct sequences with controlled cross-correlation properties, improving resource reuse while reducing sequence design complexity.
Solution Approach 2:
The patent segments the sequence design problem into base sequence generation and cyclic shift application. By dividing the sequence creation process into these two stages, the system can use a small set of simple base sequences and generate a larger number of derived sequences through cyclic shifts, reducing the overall complexity of sequence design while maintaining the ability to support multiple users with low cross-correlation.
3Reliability
If sequences with low cross-correlation are designed, then access collision is reduced, but detection complexity increases
Solution Approach 1:
The patent applies partial action by controlling cross-correlation to be below a threshold rather than requiring complete orthogonality. The system designs sequences with cross-correlation values below specified thresholds (e.g., 0.5 or 0.707) rather than requiring zero cross-correlation. This partial satisfaction of the low cross-correlation requirement reduces sequence design complexity while still effectively minimizing access collisions and interference, avoiding the excessive complexity of perfect orthogonal sequence design.
Data Source
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AI summary
Embodiments of the present invention provide a data generation method and apparatus, a transmitter, and a terminal. The method comprises: determining a to-be-used sequence in a sequence set, the sequence set comprising N sequences having the length of L; and processing a first symbol by using the to-be-used sequence, so as to generate a second symbol. By means of the embodiments of the present invention, the problems of the sequence design for scheduling-free access and the data processing and transmission are resolved, and impacts of access device collisions and the receiver detection complexity on scheduling-free access performance can be effectively controlled, thereby achieving the effects of effectively implementing contention-based or scheduling-free access and data transmission.