eMBMS Delay Parameter Calculation via Base Station Feedback
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Solution Overview
Problem
Conventional Multimedia Broadcast and Multicast Services (MBMS) synchronization protocols fail to accurately determine delays between the Broadcast Multicast Service Center (BM-SC) and base stations, leading to inefficient data transmission and potential data loss due to over-provisioning or late data arrival.
Innovation Solution
A method to calculate a delay parameter by transmitting a message from the BM-SC to the base station with a transmission time, allowing the base station to determine the receipt time and calculate the delay, which is then communicated back to the BM-SC for precise synchronization, using either an extension field in SYNC Protocol Data Units (PDUs) or as a non-standard PDU, and potentially based on GPS or relative time sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rough estimation is used to determine delays between BM-SC and base stations, then the determination process is simple, but data may arrive too late and be dropped or excessive buffering occurs
Solution Approach 1:
The patent implements a feedback mechanism where base stations measure the actual arrival time of SYNC PDUs and report delay measurements back to the BM-SC. The BM-SC uses this feedback to iteratively adjust and refine delay estimates, transforming a static estimation problem into a dynamic optimization process that converges to accurate delay values.
Solution Approach 2:
The patent uses preliminary delay estimates to set initial SYNC timestamps, then refines these estimates through subsequent measurements and adjustments. This preliminary action allows the system to start operations immediately while continuously improving accuracy over time.
2Reliability
If default delay parameters are used to ensure data arrives at all base stations, then data loss is prevented, but network resources are inefficiently used due to over-provisioning
Solution Approach 1:
The patent determines individual delay parameters for each base station based on its specific location and characteristics, rather than using a uniform default parameter for all base stations. This localized approach allows each base station to receive precisely the right amount of advance data, eliminating unnecessary buffering while preventing data loss.
Solution Approach 2:
The patent implements dynamic adjustment of delay parameters based on measured performance and changing network conditions. Rather than using static default parameters, the system continuously optimizes delay values to match actual transmission characteristics, improving resource efficiency while maintaining reliability.
3Measurement precision
If accurate delay measurement is implemented through message transmission and timing, then synchronized transmission is achieved, but system complexity increases
Solution Approach 1:
The patent uses existing SYNC PDU structures and communication interfaces to carry delay measurement information, rather than requiring entirely new protocols or message formats. The existing MBMS synchronization infrastructure is extended to perform multiple functions including timing distribution and delay measurement reporting.
Solution Approach 2:
The patent introduces the MCE (Multi-Cell/Multicast Coordination Entity) as an intermediary that facilitates delay measurements and coordinates timing between the BM-SC and base stations. This intermediary simplifies the interaction model and provides a centralized point for managing synchronization complexity.
Data Source
AI summary
In order to calculate a delay parameter for synchronized data transmission in a cellular communications network, a service center transmits a message to a base station including a transmission time. Upon receipt of the message, the base station determines a time of receipt of the message. A delay parameter is then determined by the base station as the difference between the time of receipt and the time of transmission. In one embodiment, the delay parameter is transmitted back to the service center by the base station.