Transparent Relay Node Reference Signal Allocation
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Solution Overview
Problem
Transparent Relay Nodes (T-RNs) face challenges in enabling link adaptation, identifying UEs for assistance, supporting PUSCH transmissions with control information, and synchronizing DL and UL HARQ transmissions in wireless communication systems.
Innovation Solution
The solution involves the Node B assigning Reference Signals (RSs) to T-RNs, allowing them to compute and transmit Channel State Information (CSI) and participate in HARQ retransmissions, while ensuring synchronized DL and UL HARQ operations by configuring T-RNs to transmit RSs and CSI-RS in specific sub-frames, and enabling T-RNs to assist in PUSCH transmissions by using orthogonal sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If T-RNs transmit reference signals in the same sub-frames as Node B, then link adaptation can be enabled for T-RNs, but reference signal interference and measurement ambiguity occur
Solution Approach 1:
The patent divides the reference signal transmission into separate time resources by introducing dedicated sub-frames for T-RN reference signals, separating them from Node B's reference signal transmission time to avoid interference and measurement ambiguity
Solution Approach 2:
The patent configures T-RNs to transmit reference signals in advance in specific sub-frames before data transmission, enabling the UE to perform channel estimation and CSI measurement beforehand, which facilitates subsequent link adaptation for T-RN assisted transmissions
2Productivity
If T-RNs participate in HARQ retransmissions, then spectral efficiency improves, but synchronization between Node B and T-RN becomes complex
Solution Approach 1:
The patent implements a feedback mechanism where the Node B sends HARQ status information to the T-RN, enabling the T-RN to synchronize its retransmission timing and parameters with the Node B, thus achieving coordinated HARQ operations without excessive complexity
Solution Approach 2:
The patent allows dynamic adjustment of T-RN transmission parameters based on real-time channel conditions and HARQ feedback, enabling flexible synchronization that adapts to varying network conditions while maintaining coordination between Node B and T-RN
3Area of stationary object
If T-RNs transmit in-band signals, then coverage extension is achieved, but large transmitter/receiver isolation is required
Solution Approach 1:
The patent segments the frequency spectrum by assigning different frequency bands for Node B and T-RN transmissions, allowing in-band operation for coverage extension while reducing the isolation requirements between transmitters and receivers through frequency separation
Solution Approach 2:
The patent introduces time division multiplexing as an additional dimension for signal separation, alternating between Node B and T-RN transmission time slots, which enables in-band spatial coverage extension while managing isolation requirements through temporal separation
Data Source
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AI summary
Methods and apparatus are described for a Relay Node (RN) that is transparent to User Equipments to transmit, together with a base station (Node B), Reference Signals (RS) to UEs, to receive RS from UEs, to perform transmissions of Transport Blocks (TBs) to the Node B or to UEs and receptions of TBs from the Node B or from UEs, where the transmissions of TBs from the RN are for retransmissions associated with a Hybrid Automatic Repeat reQuest (HARQ) process for the same TBs, and enabling the Node B to obtain control information signaled from UEs while signaling from the RN interferers with that signaling of control information.