Cross-Operator D2D Proximity Discovery via Joint Spectrum
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Solution Overview
Problem
Current methods for device-to-device (D2D) communication between mobile devices from different network operators face challenges in proximity discovery, especially when devices are in different D2D registration areas, lacking a mechanism to inform devices of each other's presence for D2D communication and requiring pre-agreed DRSF database information and static registration areas.
Innovation Solution
A method where mobile communication devices transmit identifiers and geographic locations in a third frequency band, disjoint from their respective operator bands, allowing networks to determine spatial proximity and associate devices for D2D communication sessions, even across different operator networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If devices from different operators use static D2D registration areas with pre-agreed database information, then cross-operator proximity discovery is limited to predefined regions, but devices moving outside these static areas cannot discover each other for D2D communication
Solution Approach 1:
The patent transforms the static D2D registration area concept into a dynamic system where registration areas are established on-demand based on real-time device proximity detections. Instead of predefined static regions, the system dynamically creates registration areas when devices from different operators are detected to be in proximity, allowing the network to adapt to moving devices and changing spatial relationships without requiring complex preconfiguration of multiple static areas.
Solution Approach 2:
The patent implements preliminary action by having devices transmit their identifiers and geographic locations in the third frequency band before formal D2D connection establishment. This advance information transmission allows the network to pre-identify potential D2D pairs and prepare appropriate registration areas and resources before actual D2D communication is initiated, reducing latency and enabling seamless cross-operator discovery.
2Loss of information
If a third frequency band is used for transmitting identifiers and locations, then cross-operator proximity discovery is enabled, but spectrum resources are consumed by this additional frequency band
Solution Approach 1:
The patent applies universality by designing the third frequency band as a multi-functional resource that serves both traditional cellular communication purposes and D2D proximity discovery functions. Instead of dedicating the third frequency band exclusively to D2D discovery, the system allows it to be shared for both operator types, enabling spectrum efficiency where the same frequency resources fulfill multiple communication needs simultaneously.
Solution Approach 2:
The patent uses copying by transmitting device identifiers and location information as data signals in the third frequency band rather than using separate dedicated discovery signal structures. This approach copies existing cellular communication protocols and signal formats to function in the third frequency band, reducing the need for additional specialized spectrum resources and leveraging existing spectrum efficiently for dual purposes.
3Measurement precision
If devices transmit identifiers and geographic locations continuously, then real-time proximity detection is achieved, but energy consumption and network signaling load increase
Solution Approach 1:
The patent implements periodic action by having devices transmit their identifiers and geographic locations at predetermined time intervals rather than continuously. This periodic transmission strategy maintains adequate proximity detection precision for D2D discovery while significantly reducing energy consumption compared to continuous transmission and lowering network signaling load. The interval duration is optimized to balance detection accuracy with resource efficiency.
Solution Approach 2:
The patent applies partial action by transmitting only essential proximity-related information (identifier and geographic location) in the third frequency band rather than full device state information. This selective partial information transmission achieves sufficient precision for D2D proximity determination while minimizing energy consumption and network signaling overhead by omitting unnecessary data elements.
Data Source
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AI summary
A first mobile communication device (102) is communicatively connected to a first communication network for receiving a first communication service in a first geographic area (106) and in a first frequency-band. A second mobile communication device (108) is communicatively connected to a second communication network (110), different from the first network, for receiving a second communication service in a second geographic area (112) and in a second frequency-band. The first device is transmitting, in a third frequency-band that is disjoint from the first and second frequency-bands, a first identifier of the first device and a first location of the first device. The second network is monitoring the third frequency-band and receives the information in the transmission. Under control of the first identifier, a database is consulted for determining if the first communication device is listed as associated with the second communication device. If so, a second location of the second device is determined and a spatial proximity is determined between the first device and the second device based on the first location and the second location. The spatial proximity information enables the first communication device and the second communication device to set up a device-to-device communication session.