Narrowband Receiver Wideband Sync Signal Reconstruction
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Solution Overview
Problem
Current wireless communication networks, particularly 5G New Radio (NR), pose a challenge for narrowband radio network devices to acquire network synchronization due to wideband synchronization signals that exceed the devices' receiver bandwidth capabilities, with no defined method for narrowband devices to perform network sync.
Innovation Solution
A method where a narrowband radio network device receives and combines successive, frequency-offset 'slices' or sub-band signals over a sync signal repetition period to construct a combined broadband signal, allowing detection of the full wideband sync signal, including using Fourier transforms for frequency translation and zero padding for optimal power spectrum alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a narrowband receiver is used in radio network devices, then device cost and power consumption are reduced, but the ability to receive wideband synchronization signals is lost
Solution Approach 1:
The wideband synchronization signal reception process is segmented into multiple narrowband receptions. The receiver divides the wideband signal into several frequency-offset sub-band slices, receives each slice separately using the narrowband receiver, and then combines them to reconstruct the full wideband signal. This allows narrowband receivers to access wideband signals without requiring hardware bandwidth expansion.
Solution Approach 2:
The solution transitions from a single-dimensional narrowband reception to a multi-dimensional approach by introducing frequency offset as an additional dimension. Multiple narrowband receptions at different frequency offsets are performed and combined, effectively synthesizing a wideband reception capability from narrowband components through frequency domain manipulation.
2Reliability
If the receiver bandwidth is increased to match the sync signal bandwidth, then full sync signal reception is enabled, but device complexity and cost increase
Solution Approach 1:
Instead of implementing a single wideband receiver, the system segments the wideband signal reception into multiple narrowband receptions. Each reception operates within the device's native narrowband capability, and the segments are later combined through signal processing to reconstruct the complete wideband synchronization signal, maintaining reliability without increasing hardware complexity.
3Measurement precision
If successive frequency-offset slices are received and combined, then wideband sync signal detection is enabled, but processing time and computational complexity increase
Solution Approach 1:
The system leverages the periodic nature of synchronization signals by receiving multiple frequency-offset slices during different time instances within the sync signal repetition period. This periodic reception approach allows the narrowband device to accumulate sufficient information across multiple periods while maintaining timing synchronization with the network.
Solution Approach 2:
The receiver performs frequency offset estimation and slice reception in advance before combining the slices. By preparing the individual frequency-offset slices and organizing them beforehand, the system reduces the computational burden during the final combination stage, optimizing the overall processing time and efficiency.
Data Source
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AI summary
A radio network device, having a narrowband receiver and operative in a wireless communication network, exploits the periodicity of transmission of network sync signals by iteratively receiving a plurality of frequency-offset portions of the sync signal, and then assembling the portions to recreate the entire sync signal. The recreated sync signal is then processed to attempt network detection and synchronization. In some embodiments, frequency/time compensation may be applied to the received and stored sync signal portions, prior to their combination, to compensate for uncertainty in the frequency drift (and time drift due to frequency error) of the sync signal location.