Multicast Broadcast Synchronization in Wireless Access Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Synchronization of multicast and broadcast transmissions across multiple base stations in OFDMA wireless access systems is challenging due to geographical distribution and varying transport mediums, leading to desynchronization and reduced macrodiversity benefits.
Innovation Solution
A method for transmission synchronization that involves generating a data payload frame with a frame number including a generating time and an offset to account for transfer time, ensuring all base stations transmit data at the same time, using a controller, gateway, and base stations to distribute and combine offsets for precise timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If base stations are geographically distributed to cover large areas, then coverage area is improved, but synchronization precision deteriorates due to varying transport medium delays
Solution Approach 1:
The system performs preliminary measurements of transport medium delays between the controller and each base station before actual multicast/broadcast transmission. These measurements are used to pre-calculate compensation values that are applied to the transmission timing of each base station, ensuring synchronized delivery despite geographical distribution and varying transport delays
Solution Approach 2:
The system dynamically adjusts transmission timing parameters for each base station based on measured transport medium characteristics. By changing the transmission time parameter individually for each base station according to its specific delay characteristics, the system achieves synchronized arrival at mobile stations while maintaining large geographical coverage
2Adaptability or versatility
If different transport mediums are used to connect base stations, then network flexibility and coverage are improved, but transmission timing synchronization deteriorates due to varying transfer times
Solution Approach 1:
The controller acts as an intermediary that mediates between the data source and geographically distributed base stations connected via different transport mediums. It performs centralized delay measurements and calculations, then distributes compensated timing information to each base station, enabling synchronized transmission despite heterogeneous transport medium characteristics
Solution Approach 2:
The system changes the transmission timing parameter for each base station individually based on its specific transport medium characteristics. By measuring and compensating for varying delays in different transport mediums (E1/T1, OC3, satellite, etc.), the system maintains precise synchronization while supporting network flexibility and adaptability
3Strength
If macrodiversity transmission is implemented across multiple base stations, then received signal strength is improved, but transmission synchronization becomes more difficult to achieve
Solution Approach 1:
The controller serves as a central intermediary that manages the complexity of synchronization for macrodiversity transmission. It performs centralized delay measurements, calculates compensation values for each base station, and coordinates transmission timing, thereby simplifying the overall synchronization task while enabling multiple base stations to transmit simultaneously with proper timing alignment for macrodiversity benefits
Solution Approach 2:
The system performs preliminary delay measurements and synchronization calculations before initiating macrodiversity transmission. By pre-configuring timing compensation values for each base station based on measured transport delays, the system reduces the complexity of real-time synchronization while maintaining the signal strength benefits of macrodiversity transmission
Data Source
AI summary
In a method for multicast and broadcast synchronization a data payload frame is generated from a data payload. A frame number is assigned to the data payload frame, wherein the frame number includes a generating time of the data payload frame. The data payload frame is distributed to a plurality of base stations in a wireless access system. The offset spans a travel time of a data payload frame from the controller to the plurality of base stations as well as a scheduling time and a multiplexing time.