Slow MAC-e for Autonomous Transmission in HSUPA
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Solution Overview
Problem
The 3GPP RAN systems face inefficiencies in processing resources due to autonomous uplink transmissions by UEs without prior resource allocation, leading to increased complexity and potential degradation of scheduled transmission performance, particularly in high UE numbers, where 'Rise over Thermal' margins become significant.
Innovation Solution
Implementing a control parameter independent of air interface TTI or HARQ processes to define the minimum time interval for new transmissions, decelerating the exchange rate between the MAC-e and physical layers, and introducing a 'virtual TTI' or 'SDU inter-arrival rate' to optimize packet transmission and reduce control overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If autonomous transmission is allowed for multiple UEs without prior resource allocation, then uplink transmission flexibility is improved, but Node B processing complexity increases
Solution Approach 1:
The patent segments the autonomous transmission process by introducing a MAC-e PDU structure that separates new data packets from retransmissions. The MAC-e PDU includes a packet identifier field that allows the Node B to efficiently identify and process different UEs' transmissions without requiring complex scheduling for each individual packet, thereby reducing processing complexity while maintaining transmission flexibility.
Solution Approach 2:
The patent introduces a MAC-e layer as an intermediary between the physical layer and higher layers. This MAC-e layer handles the autonomous transmission logic, packet assembly, and scheduling decisions, shielding the Node B's physical layer processing from the complexity of managing multiple autonomous UEs. The MAC-e PDU format standardizes the interface, making Node B processing more predictable and less complex.
2Speed
If autonomous transmissions are permitted for non-scheduled UEs, then transmission speed is improved, but Rise over Thermal margins are degraded
Solution Approach 1:
The patent implements periodic transmission opportunities for autonomous UEs through the MAC-e PDU structure, which organizes transmissions in regular intervals rather than continuous unscheduled access. This periodic structure allows the system to control the aggregate data rate and power consumption, preventing excessive Rise over Thermal conditions while still providing timely transmission opportunities for autonomous UEs.
Solution Approach 2:
The patent changes the parameter of transmission timing by introducing the MAC-e PDU with explicit timing and scheduling information. Instead of allowing completely unscheduled transmissions, the system uses the MAC-e layer to manage transmission parameters such as packet size, timing, and power allocation, thereby controlling the impact on Rise over Thermal margins while maintaining the benefits of autonomous transmission.
3Stability of the object's composition
If minimum set transport formats are defined for autonomous transmission, then backward compatibility is improved, but control overhead increases
Solution Approach 1:
The patent creates a universal MAC-e PDU structure that serves multiple functions: it maintains backward compatibility with existing transport formats through the minimum set definition, while simultaneously enabling efficient autonomous transmission management. The packet identifier field and standardized MAC-e PDU format allow the same structure to handle both legacy scheduled transmissions and new autonomous transmissions, reducing the need for separate control mechanisms and thereby reducing overall control overhead.
Data Source
AI summary
A system and methods for slow medium access control entity (MAC-e) for autonomous transmission during High Speed Uplink Packet Access (HSUPA), and for service specific transmission time control in HUSPA, wherein a control parameter that is independent from the air interface transmission time interval (TTI), hybrid automatic repeat request (HARQ) processes or enhanced dedicated transport channel (E-DCH) scheduling is used. This control defines the minimum time interval between subsequent new transmissions. The control has no impact on retransmissions, which are performed normally.