Multi-Symbol OFDM Synchronization Signals for High-Frequency Coverage
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Solution Overview
Problem
Existing synchronization signal designs for cellular networks operating above 52.6 GHz face challenges with limited coverage and increased path loss due to higher subcarrier spacing, leading to inefficiencies in radio resource management and beam management.
Innovation Solution
The proposed solution involves generating and transmitting synchronization signals using multiple OFDM symbols, where the number of symbols is dependent on subcarrier spacing, utilizing pure m-sequences cyclically shifted with specific cyclic shifts, and incorporating these signals into physical broadcast channels and radio resource management measurements to enhance coverage and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If higher subcarrier spacing is used for cellular networks operating above 52.6 GHz, then transmission bandwidth is improved, but coverage is limited and path loss increases
Solution Approach 1:
The synchronization signal is segmented across multiple OFDM symbols instead of being confined to a single symbol. This segmentation allows the signal energy to be distributed over multiple time instances, effectively increasing coverage without requiring higher subcarrier spacing, thus resolving the contradiction between transmission bandwidth and coverage.
Solution Approach 2:
The patent transitions from a single-symbol synchronization signal to a multi-symbol synchronization signal, adding the time dimension (number of symbols) as an additional degree of freedom. This allows the system to maintain high subcarrier spacing for bandwidth efficiency while extending coverage through temporal repetition of the synchronization signal.
2Productivity
If higher subcarrier spacing is used, then transmission efficiency is improved, but path loss increases
Solution Approach 1:
By segmenting the synchronization signal across multiple OFDM symbols, the patent reduces the path loss impact on each individual symbol while maintaining overall transmission efficiency. The segmented structure allows for better signal detection despite higher path loss associated with increased subcarrier spacing.
Solution Approach 2:
The patent changes the parameter of synchronization signal duration from one symbol to multiple symbols, which compensates for the increased path loss by providing more temporal opportunities for successful signal detection, thereby maintaining transmission efficiency despite higher path loss.
3Reliability
If synchronization signal is transmitted over multiple symbols, then coverage is improved, but peak-to-average ratio increases
Solution Approach 1:
The patent employs dynamic cyclic shifting of the synchronization signal across different OFDM symbols. This dynamic approach allows the signal to adapt to varying channel conditions and reduces the peak-to-average ratio by distributing signal energy more evenly across time, while still achieving improved coverage through multi-symbol transmission.
4Quantity of substance
If more cyclic shifts are used for sequences, then number of physical cell identifiers increases, but device complexity increases
Solution Approach 1:
The patent makes the cyclic shift parameter serve multiple functions: it identifies the physical cell identifier and simultaneously adapts to different subcarrier spacing configurations. This universal use of cyclic shifts allows the system to support a large number of cell identifiers without proportionally increasing device complexity, as the same mechanism handles both identification and adaptation tasks.
Data Source
AI summary
An apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: generate (606) a synchronization signal for transmission over one or more symbols, wherein the number of symbols is dependent on a subcarrier spacing.