Dhanesh Raj

Performance measurement and analysis of long range Wi-Fi network for over-the-sea communication

Currently, Indian fishermen use handheld radios or satellite phones for offshore communication. While the former is based on broadcast communication with its range limited by Line-of-Sight, the latter is expensive. Therefore, lack of connectivity-at-sea is a huge problem for many Indian fishermen. Hence, this work prescribes a hierarchical point-to-multi-point backhaul network using long range (LR) Wi-Fi technology. It is a multi-hop network consisting of base stations and clusters of boats. Each boat-cluster forms a wireless mesh access network. A field-trial was conducted at sea to measure and analyze the coverage and connectivity of the P2mP LR Wi-Fi backhaul network, using commercially available 5 GHz base stations, antennas and customer premises equipment (CPE). Several parameters such as transmission power level, mechanical antenna tilt at the base station and channel bandwidth were fine-tuned to maximize the range. This paper discusses the observations and the results obtained.

Realizing cost-effective marine internet for fishermen

Offshore fishing is a common occupation providing the livelihood for tens of millions worldwide. Since each fishing trip takes 5-7 days, it could be a depressing and sometimes dangerous activity especially since the fishermen have no easy way to communicate with the mainland. Currently, there is no economically viable way to stay connected. We have developed a cost-effective system for marine internet connectivity that provides assured 40+ km range which can be further extended opportunistically. This paper describes the field trials conducted to practically realize the system and presents the encouraging results obtained.

Delay tolerant routing protocol for heterogeneous marine vehicular mobile ad-hoc network

Delay tolerant networks (DTN) are characterized by lack of end-to-end communications and stable infrastructures. This paper deals with DTN networks consisting of a number of heterogeneous mobile fishing vessels where some nodes, referred to as adaptive nodes, are capable of communicating through long-range Wi-Fi whereas other nodes are having simple Wi-Fi access network. The nodes form different clusters consisting of adaptive nodes and access nodes. Message routing in this heterogeneous network happens through adaptive nodes if the source and destination nodes belong to different clusters. Real data from field study reflects that mobile nodes in this network follow Gaussian-Markov mobility model and may have high inter-meeting arrival time based on deployment and node density. Our proposed DTN routing protocol incorporates simple encounter-based message forwarding and achieves lower latency and high delivery probability in the range of 90–98% for most of the scenarios. The proposed protocol is verified through a realistic mobile ad-hoc wireless simulator.

Performance Assessment of an Extremely Challenged Mobile Infrastructure Network over the Oceans

A novel cost-effective network architecture for providing Internet connectivity to marine fishermen has been successfully prototyped by our research center. A pilot deployment is in progress in a coastal Indian village. This will improve the quality of life of the financially constrained marine fishermen who spend 5--7 days offshore on average for a single fishing trip; it will also help in their safety and security. The architecture employs multiple long range Wi-Fi (LR Wi-Fi) based infrastructure networks stitched together as backhaul. The access network consists of Ethernet and Wi-Fi mesh. The fishermen connect to the on board Wi-Fi access point cum router using their smart phones and are able to use all the apps and services on their smart phone. While the primary infrastructure network uses onshore base stations, the secondary infrastructure networks use boats as mobile base stations. Three field trials were conducted over the ocean using one onshore base station and two mid-sized boats known as trawlers. The performance of both primary and secondary infrastructure networks was assessed during these field trials. This paper describes the impressive results obtained in assessing the performance of the secondary infrastructure network.

A Resilient Self-Organizing Offshore Communication Network for Fishermen

Fishing is a major industry that provides the livelihood for millions of families worldwide. The fishing vessels are typically at sea for 5--7 days at a stretch completely cut off from the land. In a low-cost offshore communication system for fishermen currently being developed, a multilevel P2MP backhaul network connects clusters of boats at the fishing zones. Each cluster forms a wireless mesh network with multiple potential gateways to the backhaul network. This work proposes a resilient lightweight protocol for optimized dynamic provisioning of the backhaul network based on an adaptive, demand driven algorithm. A local controller, capable of running on any access router, selects the optimal subset of gateways so that the rest can be reconfigured as mobile base stations or switched to power saver mode. It assigns every boat in a cluster to the most appropriate gateway maximizing the utilization of gateways. A proof-of-concept implementation has been done with a hardware test bed and the results are very encouraging.

An Assistive Device for Managing Urinary Incontinence

Urinary Incontinence (UI) is a common and embarrassing condition affecting people of all age groups, especially women, aged population, patients with certain neurologic diseases, children born with spinal cord disorders, spinal trauma and other diseases of spinal cord, after certain pelvic and prostatic surgeries, etc., and they cause significant emotional impact on their quality of life. In this paper, we proposed a novel design of an assistive device for managing UI. We have also designed and developed a system for real time monitoring of urinary bladder and a control system for wirelessly triggering the opening and closing of an artificial sphincter by patients. One of the major requirements is on selecting a suitable electrically activated polymer that provides maximum deflection for minimum applied power. In this work we have studied and analyzed existing polymers and selected the most suitable Ionic Electro-Active Polymer (EAP) based on the results from the analysis. For continuous operation of this assistive device, one of the major challenges is to optimize the power usage. To achieve that goal, we have proposed and implemented a state transition algorithm for real-time optimization of power usage. The complete system is designed to be scalable to monitor multiple patients using one external device. Use of this device will provide an opportunity for the patients to engage in regular activities and also provide assistance and support for caretakers in old age homes and hospitals. A prototype of the complete system is developed, tested and results are described in this work.