Network accessibility has become increasing important in today's fast paced world. In fact, it is difficult to imagine our new generation that cannot benefit from a wireless network. Companies across a broad spectrum, manufacturers, warehouses, retailers, schools, hospitals, hotels and service facilities are implementing wireless networks in record numbers. The benefits they find include mobility, simpler installation and lower cost of ownership. The research on wireless technologies is of key importance and therefore, a lot of the researchers in electrical and computer engineering schools intend to contribute in this field. Similarly, we also focus on multiple areas of wireless communications and most of them are listed below: 

1. Vehicular Ad hoc Network (VANET)
    Vehicular Ad hoc Network (VANET) mostly provides wireless communication among vehicles (called Vehicle to Vehicle or V2V communication) and between vehicles and the equipment installed at the roadside (called Vehicle to Infrastructure or V2I Communication). As vehicles move at the higher speed, therefore, network topology changes rapidly. Another effect of this mobility is the short link lifetime and variable network density. This makes it challenging to maintain vehicles’ proximity information with minimum information exchange within the VANET. Therefore, various other wireless technologies have been tested in VANET such as 3G, LTE, WiMaX, and so on. We have performed some interesting research in this broad field so far. 
 
1.1. Named Data Networking in VANET
    Named Data Network (NDN) is a new and an extension of basic Information Centric Networking (ICN) architecture for future networks. Since NDN is at an early bud stage, therefore, many issues are still unidentified and open. Therefore, we highlighted a few of the NDN challenges in perspective of the Vehicular Networks. These issues include vehicular NDN architecture, naming, name resolution, routing or forwarding strategies, content store, forwarding information base, pending interest table management and policies, security and trust issues, etc. Our current research focus is to improve the reliability and robustness of the interest forwarding strategies, dynamics of a PIT entry lifetime, restricting the broadcast storm caused by interest/data propagation in basic ICN architectures such as Content Centric Network (CCN) and Named Data Network (NDN). 

NDN enabled Vehicular Networks


1.2. Handover in WiMaX enabled Vehicular Networks
    WiMAX offers promising data rate, low deployment cost and support for Vehicular Networks (VNs). In VNs, vehicles have high mobility as they move from the coverage area of a serving RSU (S-RSU) to a Target-RSU (T-RSU). When moving from an S-RSU to another RSU, every vehicle should complete handover process. However, seamless handover is one of the major challenges in WiMaX while supporting real-time applications for VNs. Handover latency mainly results from the T-RSU selection and scanning of multiple channels. We, therefore, proposed an efficient network assisted handover scheme which attempts to reduce the T-RSU selection and scanning time of Mobile Stations (MSs) during the handover process. Using the NS-2 simulator, for evaluation, we compared our scheme with some existing solutions.
Handover Scenario in WiMaX enabled Vehicular Networks

1.3. Delay Tolerant Networks in VANET
    Vehicular delay tolerant networks have proven to be a low-cost solution with an attempt to provide connectivity in the presence of vehicular mobility. However, the relay selection in VDTN is still an open issue. Therefore, we proposed a bivious relaying scheme to minimize the communication outage experienced by a vehicle within an uncovered area between two distant neighboring Road Side Units (RSUs). Our proposed scheme selects two relays for a target vehicle, one when it leaves the coverage area and the other when it is on the way to enter the next distant RSU. The analytical results show that the bivious relaying scheme provides a better minimized communication outage time compared to the single relaying scheme.
Infrastructure-to-relaying-vehicle (I2RV) architecture 

2. Cyber Physical Systems
    Cyber world and the physical world were considered as two different entities in the past decade. However, researchers have found that these two entities are closely correlated with each other after integration of sensor/actuators in the cyber systems. Cyber systems became responsive to the physical world by enabling real time control emanating from conventional embedded systems, thus emerging a new research paradigm named Cyber Physical System (CPS). Therefore, we investigated the major challenges in the integration of cyber world with the physical world and its applications. In addition, we also proposed an architecture which contains several modules supporting the CPS. We found that every module in our proposed architecture has its own significance and can be applied to various applications.
CPS Proposed Architecture


3. Underwater Sensor Networks
    Energy efficiency in Underwater/Acoustic Sensor Network (UASN) is a key challenge for extending network lifetime. Based on analysis of energy consumption for LEACH in underwater channel, we proposed a novel clustering scheme for UASN based on grouping nodes to ensure that nodes balance energy load by considering the residual energy of candidate nodes. We introduced a formation of small clusters (groups) within clusters named as Nested Clustering (NC). Our Energy Efficient Nested Clustering (EENC) scheme divides each cluster into small groups and nodes in each of those small groups switch their operation modes (idle and awake) to achieve energy efficiency. Through simulation results, it is observed that our proposed EENC scheme has better network lifetime and optimized data duplication as compared to the existing cluster schemes.
Nested Clustering in Underwater Sensor Nodes

4. Wireless Sensor Networks
    It has been observed that Wireless Sensor Network (WSN) is one of the dynamic research areas because, it has been investigated by many researchers due to its diversified applications i.e. Health, traffic, agriculture, military, goods tracking, etc. WSN comprises low-power wireless nodes or motes and gateway node(s). The task of wireless node is to sense the environment or its physical parameters (that is done with the help of sensors or sensing modules attached with the sensor nodes) and communicate the sensed data to the gateway node(s). Gateway node(s) can either be connected to the computer or directly to the network. The sensed data is either stored in a central online database or at the computer that is attached with the gateway node(s). There are several areas that are intensively investigated by the researchers, which includes sensor platform design, energy efficient routing and MAC protocols, deployment strategies and the list goes on. Along with these applications, an active research is also being carried out where sensing is accomplished without using any physical sensors or sensing modules and termed as Sensor-less WSN (SL-WSN).

    We experimentally investigate the effect of fast moving object on the RSSI in the SL-WSN in the presence of the ground effect and antenna orientation in the elevation direction. In the experimental setup, the MICAz mote pair was placed on the ground, where one mote acts as a transmitter and the other as a receiver. The transmitter mote’s antenna was oriented in the elevation direction with respect to the receiver mote’s antenna. The fast moving object, i.e. The car, was passed between the nodes and the fluctuations in the RSSI are observed. The experimental results show some sequential pattern in RSSI fluctuations when the car moves at some relatively slow speed. These statistics can be further utilized while designing applications for SL-WSN(s).

                      
   An experimental setup where the car is passing between MICAz Mote pairs.