ePDCCH Random Access Prior to Configuration
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Solution Overview
Problem
The capacity of the physical downlink control channel (PDCCH) in LTE networks limits the admission rate during the random access procedure, as the enhanced physical downlink control channel (ePDCCH) cannot be used by a UE until it is formally configured, restricting the capacity of the random access procedure.
Innovation Solution
Enabling the use of the enhanced physical downlink control channel (ePDCCH) for receiving downlink assignments during the random access procedure prior to formal configuration, allowing ePDCCH to be used even before the radio resource control (RRC) configuration is completed, thereby alleviating the PDCCH bottleneck.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the enhanced physical downlink control channel (ePDCCH) is used before formal configuration, then the capacity of the random access procedure is enhanced, but the device complexity and configuration management become more complex
Solution Approach 1:
The patent applies preliminary action by enabling the ePDCCH to be used during the random access procedure before the formal RRC configuration is completed. The UE is allowed to monitor and receive downlink assignments on ePDCCH resources that are pre-configured or implicitly determined, without waiting for the formal configuration message. This resolves the contradiction by advancing the usage of ePDCCH to improve random access capacity while avoiding the need for complex additional configuration management, as the configuration can be completed later without affecting the initial random access procedure.
2Ease of operation
If the common search space on PDCCH is used for random access response, then the procedure is simple, but the admission rate is limited by PDCCH capacity
Solution Approach 1:
The patent merges the functionality of PDCCH and ePDCCH in the random access procedure. The UE is configured to monitor both PDCCH common search space and ePDCCH resources for random access responses. The network can distribute random access response messages across both channels, effectively combining their capacities. This resolves the contradiction by maintaining the simplicity of using common search space while overcoming the PDCCH capacity limitation through the additional ePDCCH resources, thereby increasing the admission rate without significantly complicating the procedure.
Data Source
Figure 1a~1b
Figure 2
Figure 3~4
AI summary
A method in a wireless terminal of a telecommunications system comprises the steps of using an enhanced physical downlink control channel to receive a downlink assignment of one or more downlink messages relating to a random access procedure, prior to an enhanced physical downlink control channel being formally configured for use with the wireless terminal. A corresponding method in a network node of a telecommunications system comprises the steps of transmitting a downlink assignment of one or more downlink messages relating to a random access procedure to a wireless terminal using an enhanced physical downlink control channel, ePDCCH, prior to the enhanced physical downlink control channel being formally configured for use with the wireless terminal. This has the advantage of relieving a PDCCH bottleneck of the telecommunications system.