R-PDCCH Mapping via OFDM Symbol Segmentation in LTE Relay Backhaul
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Solution Overview
Problem
In LTE communication systems, there is no reasonable mapping solution for the Relay Physical Downlink Control Channel (R-PDCCH) using reserved Physical Resource Blocks (PRBs, leading to potential resource conflicts or overflows, which hinders effective utilization of backhaul resources.
Innovation Solution
The method involves the eNB mapping downlink grant information of a relay node onto an available OFDM symbol of a pre-allocated PRB pair used for R-PDCCH, with available OFDM symbols in the PRB pair used for bearing a Physical Downlink Shared Channel (PDSCH) of the relay node, allowing for efficient resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the eNB semi-statically reserves PRBs for R-PDCCH transmission, then the R-PDCCH can be transmitted to the relay node, but resource conflict or overflow occurs and backhaul resources cannot be effectively utilized
Solution Approach 1:
The patent segments the PRB pair into two slots, with the first slot dedicated to R-PDCCH transmission and the second slot dedicated to PDSCH transmission. This temporal segmentation allows different channels to share the same frequency resources without interference, resolving the resource conflict while maintaining transmission reliability and improving backhaul resource utilization efficiency.
Solution Approach 2:
The patent transitions from frequency-domain resource allocation to time-domain resource allocation by introducing slot-based division within the PRB pair. This dimensional change allows the R-PDCCH and PDSCH to coexist in the same frequency band without conflict, effectively utilizing backhaul resources while ensuring reliable control channel transmission.
2Ease of operation
If the RN transmits PDCCH to UE on former OFDM symbols, then downlink control information can be delivered, but the RN cannot receive PDCCH from eNB simultaneously
Solution Approach 1:
The patent segments the subframe into two slots with distinct transmission directions: the first slot is configured for downlink PDCCH transmission from eNB to RN, while the second slot is configured for uplink PDCCH reception from RN to eNB. This temporal segmentation enables bidirectional communication without simultaneous transmission-receiving conflict, improving both ease of operation and adaptability.
Solution Approach 2:
The patent implements periodic switching of transmission direction between slots, with the first slot dedicated to downlink transmission and the second slot dedicated to uplink reception. This periodic action pattern allows the relay node to alternately perform transmission and reception functions, resolving the conflict between downlink control transmission and bidirectional communication capability.
Data Source
AI summary
The present invention discloses a transmission method and system for a Relay Physical Downlink Control Channel (R-PDCCH). The method comprises the steps of: an eNB bearing downlink grant information of a relay node onto an available Orthogonal Frequency Division Multiplex (OFDM) symbol of a first slot of a pre-allocated Physical Resource Block (PRB) pair used for bearing the R-PDCCH, wherein available OFDM symbols in the PRB pair, other than the OFDM symbol used for the downlink grant information, are used for bearing a Physical Downlink Shared Channel (PDSCH) of each relay node; the eNB transmitting the PRB pair bearing the downlink grant information and the PDSCH to the relay node. The present invention is well applicable to a link between an eNB and a relay node, and meanwhile enables backhaul resources to be used adequately.