Frame Synchronization Using Iterative BER Estimation
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Solution Overview
Problem
Conventional digital communication systems face inefficiencies in frame synchronization, particularly during late call entry, resulting in significant audio information loss due to the need for prolonged synchronization processes and reliance on synchronization patterns, which can lead to delays and data loss.
Innovation Solution
The method involves selecting and decoding bit sequences S0 and S1 from a data burst to determine Bit Error Rate (BER) estimates, iteratively modifying and combining these estimates to identify the location of vocoder voice frames within the data burst, thereby reducing late call entry time and audio information loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a known synchronization pattern is transmitted prior to data bursts to establish frame synchronization, then synchronization accuracy is improved, but bandwidth utilization deteriorates due to the synchronization pattern not including user and/or control data
Solution Approach 1:
The patent combines the synchronization function with existing data burst transmissions by embedding synchronization information within the data bursts themselves, rather than using separate dedicated synchronization patterns. This merging eliminates the need for separate synchronization transmissions while maintaining synchronization capability, thereby improving bandwidth utilization without sacrificing synchronization accuracy
Solution Approach 2:
The data bursts are designed to serve multiple functions simultaneously: they carry user data, control information, and synchronization signals. By making the data bursts universal carriers that perform multiple roles, the system eliminates the need for separate dedicated synchronization patterns, thus improving bandwidth efficiency while maintaining synchronization functionality
2Adaptability or versatility
If SACCH information is used to facilitate timing synchronization for late call entry, then late call entry capability is improved, but call entry time deteriorates due to the need to wait for multiple superframes
Solution Approach 1:
The patent prepares synchronization-relevant information in advance by embedding it within the ongoing data bursts during normal operation. When a late call entry occurs, the FNE can immediately process this pre-positioned information without waiting for multiple superframes, thus reducing call entry time while maintaining the ability to handle late entries
Solution Approach 2:
The patent enables the FNE to skip the traditional waiting period for multiple superframes by directly processing synchronization information that is already present in the data bursts. This rushing through of the synchronization process significantly reduces the time required for late call entry while maintaining synchronization accuracy
3Reliability
If the FNE waits for inbound talker SACCH data to establish frame synchronization during late call entry, then synchronization reliability is improved, but audio information loss deteriorates due to the extended synchronization duration
Solution Approach 1:
The patent places synchronization information in advance within the data bursts that are already being transmitted. This allows the FNE to perform synchronization immediately upon receiving these bursts without waiting for SACCH data, thereby reducing the window during which audio information is lost while maintaining synchronization reliability through the use of dedicated synchronization fields
Data Source
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AI summary
Systems (1600) and methods (1500) for frame synchronization. The methods involve: extracting bit sequences S0 and S1 from a Bit Stream ("BS") of a Data Burst ("DB"); decoding S0 and S1 to obtain decoded bit sequences S'0 and S'1; using S'0 and S'1 to determine Bit Error Rate ("BER") estimates (516, 518); combining the BER estimates to obtain a combined BER estimate; modifying S0 and S1 so that each includes at least one bit ofBS which is not included in its current set of bits and so that it is absent of at least one of the bits in the current set of bits; iteratively repeating the decoding, using, combining and modifying steps to obtain more combined BER estimates; analyzing the combined BER estimates to identify a minimum combined BER estimate; and using the minimum combined BER estimate to determine a location of a vocoder voice frame within DB.