Research Terms
Researchers at the University of Central Florida have developed a mobile visible light communication (VLC) receiver that overcomes the signal quality and efficiency issues that hamper the widespread use of VLC systems. With the ability to provide secure, high-throughput indoor wireless networking, VLCs are ideal for multi-use office environments and Li-Fi (light fidelity) applications. However, vibrations from movements such as typing on a laptop or handling a smartphone may cause a VLC receiver to lose efficient optical signal reception. Such regular office activities can trigger attenuation and impose a time-varying inter-symbol interference (ISI) on received optical signals. Consequently, this limits the viable communication bit rate and effective range of indoor VLC systems. As a result, existing VLC systems have limited bandwidth and transmission bit rates (?20 Kbps) and a short communication range (?1 m).
The UCF-developed VLC receiver resolves these issues with a design that conforms to surfaces of different IoT shapes such as laptops, smartphones, TV monitors and virtual reality headsets. Experimental results of a prototype VLC system showed a 20 Mbps VLC link over a 7.1 m distance with a bit error rate of less than 10^-5. That is, a speed of 0.2 m/s, acceleration of 43.02 m/s^2, displacement of 37.74 mm, and frequency of 6.27 Hz. The testing included subjecting the VLC receiver body to intense vibrations.
Stage of Development
Prototype available.
Technical Details
The invention comprises off-the-shelf-components, including a photodetector (PD) array to generate data-carrying photo-current in response to receiving a visible light communication; a transimpedance amplifier; a high pass filter; and a wideband voltage amplifier. The large aggregate receiver surface area can be a cubical design or flat structure for a wider FOV and reception range. To overcome the detrimental effects of time-varying ISI without exponentially increasing computing time, the inventors developed an optimal multiple-symbol detection (MSD) module and a decision feedback affine projection algorithm (DF-AP A) module.
The University of Central Florida invention is a genetic algorithm framework to explore optimized multi-element free-space optical (FSO) transceiver tiling patterns to ensure maximal signal-to-interference and noise ratio (SINR). The framework also serves to minimize the effects of vibration of the mobile platform and atmospheric turbulence. With the ever-growing demand for high-speed mobile data, smart free-space optical (FSO) communication is a critical technology due to its significantly faster data transfer rate, higher security, lower costs, and reduced power usage. This invention improves the performance of FSO communication links by multi-element tiling the laser-based transceivers, which is capable of in-band full-duplex (IBFD) communication.
Design of a multi- element FSO transceiver array for mobile communication links, Proc. SPIE 11678, Free-Space Laser Communications XXXIII, 1167805 (10 March 2021); doi: 10.1117/12.2582633
The University of Central Florida invention is a disconnection-tolerant routing protocol, Binary State Distance Vector Routing (BSDVR), that can provide unicast routing on partitioned networks. BSDVR introduces binary state information for distance vector (DV) entries to compute unicast paths even if the network is partitioned. Even when a network is partitioned, BSDVR successfully calculates the shortest paths among all nodes by augmenting the Bellman-Ford algorithm with the binary state information. BSDVR generates more control overhead during single link failures that do not cause partitions. In terms of partition-causing link failures, BSDVR effectively avoids the count-to-infinity problem and operates with control overhead less than traditional DV routing by an order of magnitude, leading to much better convergence times for failures. With proper tuning of a data plane, BSDVR can attain a hybrid between traditional DV and epidemic routing and enable unicast-like paths more suitable for limited-capacity networks.
Partnering Opportunity
The research team is seeking partners for licensing and/or research collaboration.
Stage of Development
Prototype available.
Distance Vector Routing in Partitioned Networks, 2022 IEEE International Symposium on Local and Metropolitan Area Networks (LANMAN), 2022, pp. 1-7, doi: 10.1109/LANMAN54755.2022.9820113.
