D2D Communication Link Establishment in LTE
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Solution Overview
Problem
Current device-to-device (D2D) communication technologies face challenges in efficiently operating within and outside network coverage areas, particularly in terms of spectrum usage and energy efficiency, as they require modifications to existing 3GPP LTE standards to support D2D communications effectively across various scenarios.
Innovation Solution
The implementation of techniques that allow user equipment (UEs) to receive system information indicating a D2D region defined using type 2 frame structure subframes, obtain synchronization signals for time and frequency synchronization, and establish D2D communication links using modified uplink-downlink configurations, enabling communication within and outside network coverage areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If D2D communication is implemented using existing 3GPP LTE standards, then network coverage support is maintained, but spectral efficiency and energy efficiency deteriorate due to lack of optimized D2D-specific mechanisms
Solution Approach 1:
The patent segments the LTE frame structure into dedicated D2D regions and traditional network communication regions. Type 2 frame structures are specifically designed for D2D operations, separating D2D synchronization signals, discovery signals, and data transmissions from conventional uplink-downlink frames. This segmentation enables optimized resource allocation for D2D while maintaining network coverage support through coordinated operation with the network.
Solution Approach 2:
The patent implements dynamic configuration of D2D uplink-downlink patterns that can be adjusted based on network conditions, device locations, and traffic requirements. The network can dynamically allocate resources within the D2D region and modify the D2D uplink-downlink configuration to optimize spectral efficiency and energy efficiency while maintaining reliability across different coverage scenarios.
2Adaptability or versatility
If D2D communication operates outside network coverage, then autonomy and flexibility improve, but synchronization precision and network coordination deteriorate
Solution Approach 1:
The patent implements preliminary synchronization mechanisms where devices perform synchronization procedures before entering standalone D2D operation mode. Synchronization signals are transmitted and processed in advance to establish time and frequency alignment. This preliminary action enables devices to operate autonomously outside network coverage while maintaining synchronization precision through pre-established reference signals and synchronization protocols.
Solution Approach 2:
The patent uses copying of synchronization signals and frame structures from network-operated devices to maintain synchronization precision in standalone D2D mode. Devices outside network coverage can copy and replicate synchronization patterns, reference signals, and frame structures that were previously received from the network, enabling autonomous operation with maintained synchronization accuracy.
3Reliability
If dedicated D2D regions are allocated in the frame structure, then D2D communication reliability improves, but network resource availability deteriorates
Solution Approach 1:
The patent merges D2D communication operations with network communication operations by integrating D2D regions into the overall LTE frame structure. The D2D uplink-downlink configurations are coordinated with network uplink-downlink assignments, allowing shared use of radio resources between D2D and network operations. This merging enables reliable D2D communication while maximizing network resource availability through coordinated resource allocation.
Solution Approach 2:
The patent implements multi-functional resource blocks that can serve both D2D communication and network communication purposes. The same physical resources can be allocated to D2D operations during designated D2D regions while maintaining the ability to reallocate or coordinate with network operations. This universality improves D2D reliability through dedicated resource allocation while preserving network resource availability through flexible resource management.
Data Source
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AI summary
Examples may include techniques to enable user equipment (UE) to establish a device-to-device (D2D) communication link for D2D communications with another UE. In some examples, the D2D communications may occur when either both or at least one UE is within a coverage area for a wireless wide area network (WWAN). In some other examples, both UEs may be outside of the coverage area and may utilize a third UE to provide or relay information for use to establish the D2D communication link.