Multi-Beam Cell Access Synchronization for High-Frequency Carriers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for transmitting synchronization signals from a network node to a wireless device are designed for wide area coverage at lower carrier frequencies and lead to numerous synchronization failures when used in communication systems using high frequency carriers, such as those projected for 5G systems, due to higher path loss and the need for narrow beams.
Innovation Solution
The network node transmits a first synchronization signal and an associated information message in multiple OFDM symbols within a subframe, using beamforming to optimize detection by the wireless device, allowing for synchronization even when the preferred beam is unknown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing methods for transmitting synchronization signals are used, then wide area coverage is achieved, but synchronization failures increase due to higher path loss at high frequency carriers
Solution Approach 1:
The synchronization signal transmission is segmented into multiple narrow beams instead of a single wide beam. Each beam covers a specific spatial sector, and the network node transmits synchronization signals sequentially across multiple beams to ensure comprehensive coverage while maintaining high signal strength in each direction, thereby overcoming path loss at high frequencies.
Solution Approach 2:
The network node periodically transmits synchronization signals in a time-varying manner across different beams. This periodic beam sweeping approach ensures that synchronization signals reach wireless devices in different locations at appropriate times, maintaining reliable synchronization despite the challenges of high frequency path loss.
2Reliability
If narrow beams are used for high frequency carriers, then path loss is compensated, but the complexity of signal transmission increases
Solution Approach 1:
The network node performs preliminary beam sweeping to identify suitable beams for synchronization signal transmission before actual data communication begins. This preliminary action establishes the beam configuration and timing in advance, simplifying subsequent signal transmission and reducing real-time complexity.
Solution Approach 2:
The beam configuration and transmission timing are made dynamic and adaptable. The network node can adjust beam directions, sweeping patterns, and transmission parameters based on detected wireless devices and channel conditions, optimizing signal detection reliability while managing transmission complexity through intelligent adaptation rather than fixed complex structures.
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 method enhances the likelihood of synchronization signal detection and reduces synchronization failures by utilizing beamforming to transmit synchronization signals repeatedly across multiple beams, ensuring reliable synchronization with high-frequency carriers.
Implementation Method 1
The network node transmits a first synchronization signal and an associated information message in multiple OFDM symbols within a subframe, using beamforming to optimize detection by the wireless device
Data Source
AI summary
Methods are disclosed which can be performed by a network node for sending to a wireless device a first synchronization signal and an associated information message, for synchronization of the wireless device with the network node. The network node and the wireless device operate in a wireless communications network. The network node sends the first synchronization signal in N OFDM symbols within a subframe, at least once in a time and frequency position in every one of the N OFDM symbols. N is equal or larger than 2. For each sending of the first synchronization signal, the network node sends an associated information message at a pre-defined time and frequency position in an OFDM symbol. The pre-defined time and frequency position is relative to the time and frequency position of the first synchronization signal. The associated information message is associated with the first synchronization signal.