Relay Link Resource Configuration via Dynamic PDCCH Offset
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Solution Overview
Problem
The existing configuration of relay link resources in wireless communication systems, particularly in 3GPP LTE-Advanced networks, results in reduced relay link resources due to excessive offset of the relay node (RN) frame relative to the base station (eNB) frame, leading to wasted resources and inefficient communication.
Innovation Solution
Configuring relay link resources by adjusting the offset of the RN frame relative to the eNB frame based on the actual length of the physical downlink control channel (PDCCH) in the MBSFN subframe, allowing for dynamic reporting of the OFDM symbol number used by the RN, thereby optimizing the relay link resources and reducing idle times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the RN frame is offset forward relative to the eNB frame to enable the RN to receive the eNB's PDCCH, then the RN can share the PDCCH with UEs under eNB coverage, but the offset is too large which reduces the relay link resources
Solution Approach 1:
The patent applies dynamics by making the PDCCH length configurable and adaptable. The eNB can dynamically adjust the PDCCH length (1-4 OFDM symbols) based on actual needs, and the RN frame offset is dynamically determined based on the actual PDCCH length rather than a fixed large offset, allowing the system to adapt between reliability and resource efficiency
Solution Approach 2:
The patent changes the parameter of PDCCH length from a fixed maximum value to a configurable parameter (1-4 OFDM symbols). By changing this parameter, the system can optimize the balance between PDCCH reception reliability and relay link resource availability, as the offset is now based on actual PDCCH length rather than a conservative maximum assumption
2Reliability
If the eNB defaults to considering the maximum PDCCH length (2 OFDM symbols) in MBSFN subframes, then the RN can reliably receive control information, but the offset is further increased which decreases relay link resources and wastes resources
Solution Approach 1:
The patent implements feedback by having the RN report its actual PDCCH length to the eNB. This feedback mechanism allows the eNB to adjust its assumptions about PDCCH length, enabling more accurate offset calculation and preventing the resource waste caused by defaulting to maximum PDCCH length assumptions
Solution Approach 2:
The system transitions from a static assumption of maximum PDCCH length to a dynamic configuration where the actual PDCCH length is determined and communicated. This dynamic approach allows the offset to be optimized based on real conditions rather than worst-case assumptions, reducing resource waste while maintaining reliability
3Adaptability or versatility
If the RN performs state conversion from receiving state to sending state or vice versa, then the RN can communicate with both UEs and eNB, but the state conversion time creates idle time/guard time which affects relay link resources
Solution Approach 1:
The patent applies preliminary action by having the RN perform state conversion in advance during the offset period. The offset time is specifically designed to accommodate the RN's state conversion from receiving to sending mode before the relay link transmission begins, eliminating the need for additional guard time during the actual data transmission
Data Source
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AI summary
A method, a base station, and a system of configuring relay link resources are provided according to the embodiments of the present invention. The method of configuring relay link resources includes: receiving an orthogonal frequency division multiplexing OFDM symbol number reported by a relay node RN, in which the OFDM symbol is used by a physical downlink control channel PDCCH of a multimedia multicast broadcast single frequency network MBSFN subframe where a relay link of the RN is located; and configuring relay link resources according to the OFDM symbol number, an offset, and a length of a PDCCH in an eNB subframe, in which the offset is an offset of an RN frame relative to the time when the RN frame is initially synchronized with an eNB frame, and is smaller than a sum of a length of the PDCCH of the MBSFN subframe where the relay link of the RN is located and a first idle time. The method increases relay link resources and reduces resource waste.