Non-Transparent Inband Relay Node for Single Frequency Network Synchronization
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing relay communications, particularly in single frequency networks, where cross-subframe channel estimation issues and uplink synchronization problems lead to degraded performance.
Innovation Solution
The implementation of non-transparent inband relay nodes in single frequency networks, where user equipment (UE) receives configuration messages for random access resources, monitors relay reference signals, and determines signal strength and timing to initiate relay communications based on specific thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If relay nodes perform transparent relay services in single frequency networks, then coverage is extended and throughput is enhanced, but cross-subframe channel estimation issues and uplink synchronization problems occur leading to degraded performance
Solution Approach 1:
The patent introduces a non-transparent relay node that acts as an intermediary between the base station and user equipment. This relay node includes a relay reference signal generator that produces dedicated reference signals for channel estimation, separating the channel estimation function from the data transmission function. The relay node processes and forwards signals while maintaining proper timing synchronization, thus mediating the communication to avoid cross-subframe channel estimation issues.
Solution Approach 2:
The patent segments the communication function by separating transparent relay services from non-transparent relay services. Non-transparent relay nodes are configured with specific random access resources and relay reference signals, allowing independent channel estimation and synchronization management. This segmentation enables different relay types to operate with optimized parameters, preventing channel estimation degradation caused by mixed-mode operations.
2Adaptability or versatility
If relay nodes operate in single frequency networks with time division multiplexing, then frequency resources are efficiently utilized, but uplink synchronization problems and timing conflicts arise
Solution Approach 1:
The patent implements preliminary timing advance adjustments before actual data transmission. The base station configures random access resources and relay reference signals with predetermined timing relationships. User equipment and relay nodes perform timing synchronization procedures in advance, establishing proper timing offsets before engaging in time division multiplexed operations. This preliminary timing configuration prevents uplink synchronization problems during actual communication.
Solution Approach 2:
The patent incorporates feedback mechanisms where relay nodes report timing information and channel conditions to the base station. The base station uses this feedback to adjust timing advance values and reconfigure random access resources as needed. This closed-loop feedback system maintains uplink synchronization accuracy while allowing flexible time division multiplexing of frequency resources.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive, for a base station, a configuration message indicating a set of random access resources associated with monitoring by a relay node. The UE may transmit a random access message using the random access resources to the relay node and a timing advance associated with uplink data transmissions by the UE. The UE may then communicate with the base station via the relay node based on the random access message. In some examples, a UE may monitor for a relay reference signal from a relay node. The UE may determine a signal strength and a timing of the relay reference signal. The UE may determine whether an RSRP satisfies a threshold receive power, and may determine whether the timing of the relay reference signal is less than a timing threshold. The UE may transmit a downlink relay request to the base station to initiate relay communications.