D2D Synchronization Signal Configuration for Energy Reduction
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Solution Overview
Problem
Current device-to-device communication methods are energy and resource-intensive due to periodic beacon transmissions and lack efficient synchronization mechanisms, especially in scenarios with limited or no network coverage, leading to increased discovery latency and energy consumption.
Innovation Solution
Configuring direct control messages and synchronization reference signals to enable identification and reuse, dynamically adapting transmission formats based on the presence of synchronization reference signals, and omitting redundant direct control reference signals when synchronization reference signals are available, thereby optimizing resource usage and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic beacon transmissions are used for device discovery, then device-to-device communication can be established, but energy consumption and resource usage increase
Solution Approach 1:
The patent implements periodic beacon transmissions at optimized intervals, using discontinuous reception (DRX) cycles where devices transmit and monitor beacons periodically rather than continuously. This maintains device discovery capability while significantly reducing energy consumption compared to continuous monitoring.
Solution Approach 2:
The patent dynamically adjusts beacon transmission parameters including periodicity, power levels, and DRX cycle lengths based on device state, capability indicators, and network conditions. By changing these parameters adaptively, the system maintains reliable discovery while optimizing energy usage for different operational scenarios.
2Measurement precision
If direct control reference signals are transmitted periodically, then coherent demodulation is enabled, but resource consumption increases
Solution Approach 1:
The patent combines direct control reference signals with synchronization reference signals into a single unified signal structure. By merging these two previously separate periodic transmissions into one, the patent maintains both channel estimation accuracy and synchronization capability while halving the resource consumption associated with reference signal transmissions.
Solution Approach 2:
The unified reference signal serves multiple functions simultaneously: it provides both synchronization information and channel estimation data for coherent demodulation. This multi-functionality eliminates the need for separate dedicated reference signals, reducing overall resource usage while maintaining measurement precision.
3Adaptability or versatility
If synchronization reference signals are transmitted autonomously without network coverage, then device-to-device communication can proceed, but energy consumption increases
Solution Approach 1:
The patent enables devices to autonomously generate and transmit synchronization reference signals without network assistance, allowing D2D communication to proceed independently. The devices self-organize into clusters with elected cluster heads that provide synchronization, enabling operation in coverage-limited scenarios while managing energy through autonomous resource allocation.
Solution Approach 2:
The patent implements dynamic adaptation of transmission formats based on the presence of synchronization reference signals. When sync signals are detected, devices adapt their transmission behavior to reuse these signals for channel estimation, reducing the need for additional reference signals and thereby lowering energy consumption in autonomous operation modes.
4Loss of time
If beacon transmission periodicity is reduced to maintain discovery latency, then discovery speed improves, but energy consumption increases
Solution Approach 1:
The patent includes capability indicators in beacon messages that provide advance information about device D2D capabilities, state, and preferred operational parameters. This preliminary information allows receiving devices to make informed decisions about connection establishment and resource allocation, reducing the need for frequent probing and thereby reducing both discovery latency and associated energy consumption.
Solution Approach 2:
The patent implements feedback mechanisms where devices exchange capability indicators and state information in beacon messages. This feedback enables receiving devices to adapt their discovery and connection strategies based on transmitter capabilities, optimizing the balance between discovery latency and energy consumption by avoiding unnecessary frequent transmissions when capabilities indicate efficient operation is possible.
Data Source
Figure 1a~1b
Figure 1c
Figure 2a
AI summary
The present disclosure relates to methods and to a wireless device, 10,20, for enabling device-to-device communication. In particular the present disclosure relates to a method comprising configuring, direct control messages and reference signals, based on the capability and state of the wireless device with regards to device to device communication. The method comprises, associating, S1a, in the wireless device, at least one direct control message to a synchronisation reference signal, configuring, S2a, the at least one direct control message and/or the synchronisation reference signal, such that a recipient can identify the association between the at least one direct control message and the synchronisation reference signal, using the configuration of the direct control message and/or the synchronisation reference signal; and transmitting, S3, the at least one direct control message.