Scrambling Code Scheduling for Frequency Offset Estimation
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Solution Overview
Problem
In LTE systems with dense network coverage, interference between neighboring cells complicates frequency offset estimation for receive-end devices, making it difficult for them to accurately receive data blocks sent by transmit-end devices.
Innovation Solution
The method involves performing scrambling code initialization at specific intervals based on a parameter threshold, scrambling data blocks with different codes, and repeating transmissions to ensure interference randomization and facilitate frequency offset estimation by the receive-end device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If scrambling code initialization is performed once in each subframe to reduce interference between neighboring cells, then interference randomization is improved, but frequency offset estimation becomes difficult for the receive-end device
Solution Approach 1:
The patent segments the data transmission into multiple subframes, with different scrambling code initialization strategies applied to different segments. Specifically, the first subframe uses one initialization approach while subsequent subframes use another, allowing frequency offset estimation in the first segment while maintaining interference randomization in later segments.
Solution Approach 2:
Different quality characteristics are applied to different parts of the transmission. The first subframe is designed with specific properties (using downlink PHICH orthogonal sequence as initialization seed) to enable frequency offset estimation, while other subframes use different initialization methods optimized for interference randomization. This local differentiation resolves the contradiction between the two requirements.
2Reliability
If data block is repeatedly sent to ensure complete reception, then reliability is improved, but frequency offset estimation becomes difficult
Solution Approach 1:
The patent performs frequency offset estimation in the first subframe before the repeated transmissions begin. By establishing the frequency offset compensation in advance using the specially initialized scrambling code in the first subframe, the receive-end device can then accurately process all subsequent repeated transmissions without suffering from the interference of changing scrambling codes.
3Object-affected harmful factors
If different scrambling codes are used for each subframe to randomize interference, then interference randomization is improved, but data transmission accuracy deteriorates due to difficulty in frequency offset estimation
Solution Approach 1:
The patent implements a periodic pattern where the first subframe follows a specific initialization rule (using downlink PHICH orthogonal sequence) to enable accurate frequency offset estimation and data reception, while subsequent subframes follow a different periodic initialization pattern for interference randomization. This periodic alternation maintains both requirements at different intervals.
Data Source
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AI summary
Embodiments of this application provide a data sending method, a data receiving method, a transmit-end device, and a receive-end device. The data sending method provided in the embodiments of this application may include: performing scrambling code initialization to generate a scrambling code; scrambling a data block based on the scrambling code; repeatedly sending the scrambled data block; performing scrambling code initialization to generate a new scrambling code when an interval after previous scrambling code initialization of the data block is greater than or equal to a preset scrambling code initialization parameter threshold; scrambling the data block again based on the generated new scrambling code; and repeatedly sending the data block scrambled again. The embodiments of this application can improve efficiency of data transmission between a transmit-end device and a receive-end device.