Uplink Scheduling Request Fallback to Random Access
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Solution Overview
Problem
In LTE-based communication systems, user equipment may experience endless scheduling request transmissions due to insufficient transmission power on the Physical Uplink Control Channel (PUCCH), leading to unsuccessful communication with the e-NodeB, especially when interference changes faster than the update timescale of semi-static parameters or in the absence of timely Transmit Power Control (TPC) commands.
Innovation Solution
Implement a method where the user equipment limits the number of scheduling requests on the PUCCH and initiates a random access transmission on the Random Access Channel (RACH) when a threshold value is reached, allowing for power ramp-up and reducing the need for extensive signaling and radio link failure procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the user equipment transmits scheduling requests repeatedly on the PUCCH channel, then the probability of successful uplink resource allocation increases, but the time and energy consumption increase indefinitely
Solution Approach 1:
The patent applies preliminary action by implementing a counter mechanism that tracks the number of scheduling request transmissions before initiating a random access procedure. This pre-established tracking mechanism allows the system to detect when repeated transmissions are occurring and switch to an alternative mechanism (random access) before time consumption becomes excessive, thus resolving the contradiction between ensuring reliable allocation and limiting time loss.
Solution Approach 2:
The patent introduces an intermediary mechanism by using a counter variable as a mediator between the scheduling request transmission process and the random access procedure. This counter acts as an intermediary that monitors transmission attempts and triggers a transition to the random access channel when a threshold is reached, thereby controlling time consumption while maintaining the possibility of successful uplink resource allocation.
2Reliability
If the user equipment increases transmission power to ensure scheduling requests are heard, then the reliability of communication improves, but the power consumption increases
Solution Approach 1:
The patent applies dynamics by implementing a dynamic transmission strategy where the user equipment adapts its behavior based on the number of failed scheduling request transmissions. When the counter indicates repeated failures, the system dynamically transitions from PUCCH transmissions to random access procedure, which inherently includes power ramp-up mechanisms. This dynamic adaptation ensures communication reliability without continuously consuming high power, as the power increase is triggered only when necessary.
Solution Approach 2:
The patent applies parameter changes by modifying the transmission approach parameter based on the counter value. When the number of scheduling request transmissions exceeds a threshold, the system changes the transmission parameter from using PUCCH to using the random access channel. This parameter change allows the system to achieve the necessary transmission power for reliability while avoiding continuous high power consumption, as the power-intensive random access procedure is activated only when PUCCH transmissions fail.
3Reliability
If the system implements extensive signaling and re-establishment procedures to handle scheduling failures, then the reliability of connection maintenance improves, but the device complexity and signaling overhead increase
Solution Approach 1:
The patent applies the taking out principle by extracting the essential function of handling scheduling failures from the complex radio link failure procedures. Instead of implementing full re-establishment procedures, the patent extracts and implements a simplified mechanism using a counter and conditional transition to the random access procedure. This extraction maintains the necessary reliability for connection maintenance while significantly reducing the complexity of signaling procedures, as the simplified mechanism only triggers when needed and avoids unnecessary re-establishment overhead.
Data Source
AI summary
The present invention relates to a method and apparatus for requesting scheduling of resources to be used for uplink communication of data in a communications system. If the repeated transmission by a user equipment of scheduling requests on an uplink control channel is determined to be unsuccessful, a random access transmission on a random access channel is initiated as a fallback procedure.