Unlicensed Carrier Synchronization via Periodic Subframe Signals
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Solution Overview
Problem
In wireless communications systems, especially in LTE systems using unlicensed carriers, ensuring continuous and periodic data frame synchronization is challenging due to non-continuous and non-periodic carrier occupation, leading to potential loss of synchronization during data communication.
Innovation Solution
A synchronization method where a network device sets and sends synchronization signals in specific subframes of an unlicensed carrier, including coarse and fine synchronization signals, to maintain frequency and time synchronization between network devices and user equipment, utilizing cell-specific reference signals and primary/secondary synchronization signals to reduce synchronization delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the system uses contention-based access on unlicensed carriers, then carrier sharing and spectrum utilization are improved, but continuous and periodic synchronization signal transmission cannot be ensured
Solution Approach 1:
The patent applies preliminary action by pre-configuring synchronization signal transmission resources and parameters before actual data transmission on unlicensed carriers. The network device determines synchronization signal transmission opportunities in advance based on configured patterns, ensuring that synchronization signals are transmitted at predetermined times even when carrier access is contention-based. This allows user equipment to maintain synchronization without requiring continuous carrier occupation.
Solution Approach 2:
The patent implements periodic action by establishing regular synchronization signal transmission intervals on unlicensed carriers. The network device transmits synchronization signals at periodic intervals according to configured transmission patterns, allowing user equipment to periodically update synchronization information. This periodic transmission ensures synchronization maintenance while accommodating the discontinuous nature of contention-based carrier access.
2Measurement precision
If synchronization signals are transmitted frequently to maintain synchronization, then synchronization accuracy is improved, but signal transmission overhead and system complexity increase
Solution Approach 1:
The patent applies partial action by transmitting synchronization signals only at necessary intervals rather than continuously. The network device determines synchronization signal transmission based on configured patterns and actual synchronization needs, sending signals at selective time points that are sufficient to maintain synchronization accuracy without requiring excessive transmission frequency. This reduces overhead while preserving synchronization precision.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting synchronization signal transmission parameters such as transmission timing, periodicity, and resource allocation. The network device can modify these parameters based on channel conditions, traffic patterns, and synchronization requirements, optimizing the balance between synchronization accuracy and system complexity. This allows adaptive control of synchronization signal transmission without fixed rigid configurations.
Data Source
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AI summary
Embodiments of the present invention provide a synchronization method, an apparatus, and a system, and relate to the communications field, so as to implement synchronization of data frame transmission between devices on an unlicensed carrier. The synchronization method is applied to synchronization on an unlicensed carrier. A network device sets a synchronization signal in a first subframe; and the network device sends the first subframe or the first subframe and a second subframe to user equipment, where the first subframe includes M orthogonal frequency division multiplexing OFDM symbols, the second subframe includes N OFDM symbols, M and N are positive integers, M > N, and the first subframe and the second subframe are subframes of an unlicensed carrier. The embodiments of the present invention are applied to synchronization signal transmission.