PDCP CFN Timing for CS Service in HSDPA Networks
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Solution Overview
Problem
Current UMTS systems face challenges in efficiently supporting Circuit Switched (CS) services within Packet Switched (PS) networks, particularly with High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA) technologies, due to differences in data transfer delays and the need for seamless data flow.
Innovation Solution
Incorporating a Connection Frame Number (CFN) as timing information in data blocks transmitted by the Packet Data Convergence Protocol (PDCP) or Medium Access Control (MAC) layer to ensure data is processed by the receiving side according to a reference time, allowing for seamless switching between CS and PS services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If CS service data is transmitted in PS network using HSDPA/HSUPA, then data transmission speed is improved, but data sequence integrity deteriorates due to different transfer delays
Solution Approach 1:
The transmitting side adds Connection Frame Number (CFN) information to each data block before transmission. This preliminary tagging allows the receiving side to later verify and correct data sequence integrity by comparing CFN values, preventing out-of-order processing issues that would otherwise result from varying transfer delays in HSDPA/HSUPA networks
Solution Approach 2:
The receiving side uses the CFN information to detect out-of-order data blocks and requests retransmission of problematic blocks. This feedback mechanism ensures data sequence integrity is maintained despite the high-speed asynchronous transmission characteristics of HSDPA/HSUPA, resolving the contradiction between speed and sequence stability
2Device complexity
If timing synchronization is not implemented, then device complexity is reduced, but data processing reliability deteriorates
Solution Approach 1:
Connection Frame Number (CFN) serves as an intermediary timing reference that is attached to each data block. This simple numerical tag acts as a mediator between the transmitting and receiving sides, enabling timing synchronization and reliable data processing without requiring complex synchronization protocols or additional signaling mechanisms
Solution Approach 2:
The system uses CFN parameter values to dynamically adjust data processing timing at the receiving side. By changing the processing timing based on CFN values rather than using fixed synchronization protocols, the system achieves reliable data processing with minimal added complexity
Data Source
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AI summary
Disclosed is a radio (wireless) communication system providing a radio communication service and a terminal, and an operation method of a Packet Data Convergence Protocol (PDCP) entity in a Universal Mobile Telecommunications System (UMTS), and more particularly, to an operation method of transmitting, by a transmitting side (transmitter), data blocks by including a Connection Frame Number (CFN) therein such that a receiving side (receiver) processes each of received data blocks by a reference time, as a method of providing a Circuit Switched (CS) service using a High Speed Downlink Packet Access (HSDPA) or High Speed Uplink Packet Access (HSUPA) technology.