Sequence Hopping in SC-FDMA Systems
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Solution Overview
Problem
In SC-FDMA communication systems, there is a need for efficient sequence hopping of CAZAC-based sequences to minimize interference and optimize resource block allocations while maintaining low implementation complexity and reducing signaling overhead.
Innovation Solution
Implementing pseudo-random sequence hopping for CAZAC-based sequences, applying the same hopping pattern across all channels and limiting the number of sequences for resource block allocations, with sequence hopping performed in units of slots, and using a subset of sequences for reduced complexity and overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sequence hopping is applied to CAZAC-based sequences, then interference is reduced and reception reliability is improved, but implementation complexity and signaling overhead increase
Solution Approach 1:
The sequence hopping pattern is determined autonomously at both transmitter and receiver using the same pseudo-random function and initialization parameters. The UE generates the hopping pattern locally based on slot number, cell ID, and other configurable parameters, eliminating the need for explicit signaling of the hopping pattern itself. This self-generating approach reduces signaling overhead while maintaining the interference reduction benefits of sequence hopping.
Solution Approach 2:
The patent applies parameter changes by using different initialization parameters for the pseudo-random sequence generator based on slot number, cell identity, and resource allocation. By dynamically changing these parameters across slots and users, the system achieves diverse sequence hopping patterns that reduce interference without requiring complex centralized control or extensive signaling.
2Reliability
If sequence hopping is applied to CAZAC-based sequences, then interference is reduced and reception reliability is improved, but signaling overhead increases
Solution Approach 1:
The receiver autonomously generates the same sequence hopping pattern as the transmitter using identical initialization parameters derived from slot number, cell ID, and UE-specific parameters. This self-synchronization mechanism eliminates the need to signal the hopping pattern itself, reducing overhead while ensuring reliable sequence generation at both ends.
Solution Approach 2:
The receiver creates a copy of the transmitter's sequence generation logic by implementing the same pseudo-random function with identical parameters. This copying approach ensures both sides use the same hopping pattern without requiring explicit transmission of the pattern information, thereby minimizing signaling overhead.
3Device complexity
If the number of sequences is limited for resource block allocations, then implementation complexity is reduced, but adaptability and versatility decrease
Solution Approach 1:
The patent achieves adaptability through parameter changes in the pseudo-random sequence initialization rather than through a large number of predefined sequences. By varying initialization parameters such as slot number, cell ID, and UE-specific identifiers, the system can generate diverse sequence hopping patterns for different resource block allocations, maintaining versatility while using a limited set of base sequences.
Solution Approach 2:
The sequence selection becomes dynamic through the use of time-varying parameters in the pseudo-random generation function. The hopping pattern changes dynamically based on slot number and resource allocation, allowing the limited set of sequences to adapt to different resource block configurations without requiring a large static library of sequences.
Data Source
AI summary
Methods and apparatuses are provided for transmitting and receiving a signal using a sequence in a wireless communication system. The method includes receiving, from a base station, information indicating whether sequence hopping is applied or not; transmitting, to the base station, the signal using a first sequence if a number of resource blocks allocated to the user equipment is less than a predetermined value; and transmitting, to the base station, the signal using a second sequence to which the sequence hopping is applied based on the received information if the number of the resource blocks allocated to the user equipment is greater than or equal to the predetermined value. The sequence hopping is performed using a pseudo-random function, and the sequence hopping is performed in a unit of a slot.