In today's time, there is a need to continually monitor the ocean shore in real time for different applications such as coastal monitoring , disaster prevention , assisted navigation etc. This requires a high data rate (order of Mbps) communication for transfer of data from an underwater environment to surface. This cannot be achieved using the traditional acoustic networks as the data rate offered by acoustic networks is in the order of kbps. Notably, for the shallow underwater environment, radio frequency (RF) based communication provides a better data rate than acoustic techniques. However, propagation loss using RF can be higher as compared to acoustic and suffers from less communication range. As RF nodes in water are battery operated, high energy‐efficiency is extremely significant. Further, there is no analysis of throughput using realistic energy model for RF shallow underwater. Hence, a realistic energy model, RSU‐Energy , a cluster‐based communication architecture in shallow water ( CRUSE ) and, a mechanism for RSU‐Energy based throughput analysis ( E‐CRUSE ) were proposed in this work. The performance in terms of duration after which the first node dies and network life is then verified using RSU‐energy. Moreover, the throughput of the network using RSU‐energy was also analysed for CRUSE.

Over the last 5–7 years, with the proliferation of mobile computing devices, there has been a tremendous increase in data usage by mobile subscribers. This has quite often resulted in network congestion, forcing the operators to either increase the available bandwidth or reduce the data‐rate per subscriber. To overcome this problem, network operators have been deploying different radio access networks, including Wi‐Fi and small cells across their coverage areas. In order to remain always best connected, several techniques have been proposed over the period for efficient network selection. All these techniques can be broadly categorised into either device‐centric or network‐centric solutions. However, both device‐centric and network‐centric solutions have their disadvantages. In this study, a ‘dual priority’ scheme is proposed and developed that takes into account the preferences of both the subscribers and the network operator. Notably, the proposed ‘dual priority’ scheme offers a combined decision for the efficient handover of subscribers from cellular to Wi‐Fi. In this work, every device has its own mechanism of ranking its preferred networks, after which the network takes the decision for offload based on the preferences and its resource availability. It has been observed that the proposed dual priority scheme results in up‐to three times reduction in the time taken for offloading decision as compared to state‐of‐the‐art network‐centric solutions.

There has been a tremendous growth in the transportation sector over the last decade. Importantly, this has also resulted in the need for communication between vehicles. However, the biggest disadvantage has been the high-speed nature of the vehicles which inhibits the stability of communication. A cluster-based technique wherein all vehicles within a region are grouped together with different levels of the hierarchy have been well investigated. However, such technique fails with dynamic variation in the traffic environment. In this paper, an adaptive clustering technique is proposed based on image-based real-time traffic identification. The novelty lies in proposing an inception v3 network with deep CNN (IP-DNN) for image-based traffic identification which then serves as the basis for selecting the best clustering technique. It has been found that such an adaptive mechanism results in up to 25% faster cluster selection as compared to static techniques. This is a significant result that provides the necessary impetus for developing real-time V2V (vehicle to vehicle) communication across varying traffic environments.

Over last 4–5 years, there has been an exponential increase in the amount of traffic transmitted over cellular network. Importantly, with humongous increase in the Wi‐Fi hotspots across many places, subscribers tend to manually switch from cellular to Wi‐Fi network. However, in this process, the operator loses the visibility of subscribers, and is not able to control the congestion in network, and importantly, is not able to provide a guaranteed quality of experience (QoE) to the subscribers. In this study, a network‐centric near‐real‐time mechanism is proposed for maintaining QoE among the subscribers but is found to be a non‐deterministic problem. Importantly, an adaptive dichotomic classification based mechanism is proposed and investigated for offloading the cellular subscribers to Wi‐Fi network, while keeping the computational complexity to less than O (log( n )), where n is the number of nodes in a binary tree. Further, an algorithm is proposed for intelligent selection of subscriber profile that would enable faster completion of the offloading process. An extensive simulation of the proposed algorithm and comparison with state‐of‐the‐art mechanisms reveal up to seven time reduction in computational time; with additional performance increase occurring with increasing number of subscribers.

One of the critical aspect in V2V (Vehicle to Vehicle) communications is secured data transfer in real-time; and critically, data not being tampered by malicious infringing. In this context, this work aims to propose an integrated cryptographic technique obtained by combining asymmetric and symmetric techniques that would be suitable for V2V environment. This paper investigates the performance of different cryptographic techniques - RSA, ECC and El-Gamal - for real-time data transfer in V2V. Particularly, these three techniques are analyzed in terms of the time taken at the transmitter and at the receiver; for various message length. It is observed that the time taken by ECC is the least, while time taken by RSA is the highest. This provide a platform for evaluating integrated El-Gamal ECC mechanism and comparing it with other integrated asymmetric and symmetric algorithm.

Over the recent years, there has been an exponential increase in the traffic over wireless network. The operators aim to provide optimum service to the subscribers while simultaneously trying to reduce the network congestion. In this regard, there has been an increased demand for network-centric vertical handover of subscribers from cellular network to Wi-Fi/small cell networks. This paper presents adaptive non-binary (called as mixed-ary) approach for classifying the subscribers; which would enable network-centric handover of subscribers. An extensive simulation based analysis has been carried out which indicate that classifying the subscribers into N sets initially and then carrying out binary classification results in upto 20% time reduction as compared to pure binary and N-ary approaches.

With the advent of smart-phones and YouTube, viewing video and multimedia content over wireless medium has gained enormous interest. In this regard, encoding the video with high-quality encoder results in humongous increase in the data-rate. Given that users tend to focus more on certain parts of video, the region of video frame that is highly viewed is encoded with best-possible quality and the other regions are encoded with decreasing quality. However, the main challenge is to ensure that adaptive encoding does not result in significant perceivable degradation in video quality. In this 2-pager for poster, the nature of region of interest (RoI) is analyzed by identifying the user's focus while watching video captured with two different camera technology. It has been observed that user's RoI follows a Gaussian distribution from left to right of the screen. At the same time, the user's RoI from top to bottom follows a distribution that is almost Gaussian, but varies with the nature of the video content. This is a significant result that will play a key role in designing an adaptive RoI for reducing the data rate while transmitting multimedia content over the network.

Over the past three decades, several man-made vehicles have being sent into space to explore the extra-terrestrial bodies. As the search for water and other useful substances in the extra-terrestrial surfaces increases, this exploration activity is set to dramatically increase over the next decade (2020); with NASA planning to explore the surface of Mars, Moon and other planets and satellites. In this regard, it is imperative to build an extremely energy-efficient communication system that will cover a large area in the range of hundreds of kilometers which unfortunately is absolutely not possible today. A two-hop communication mechanism that has been well researched in the literature is insufficient to cover the extremely large distance of extra-terrestrial surface. In this paper, a novel three-hop cluster-based hierarchical communication architecture is proposed which could be easily extended to higher number of hops. In particular, it allows the individual rovers to move large distances for collecting data and at the same time provide an extremely energy-efficient mechanism for continuously exploring the surfaces. The simulation results show that in a Martian surface, the proposed three-hop design results in a higher capacity as compared to a single-hop or a cluster-based two-hop design even when the rovers move 100 km.

There is an increasing demand by an ever-growing number of mobile customers for transfer of rich media content. This requires very high bandwidth which either cannot be provided by the current cellular systems or puts pressure on the wireless networks, affecting customer service quality. This study introduces COARSE – a novel cluster-based quality-oriented adaptive radio resource allocation scheme, which dynamically and adaptively manages the radio resources in a cluster-based two-hop multi-cellular network, having a frequency reuse of one. COARSE is a cross-layer approach across physical layer, link layer and the application layer. COARSE gathers data delivery-related information from both physical and link layers and uses it to adjust bandwidth resources among the video streaming end-users. Extensive analysis and simulations show that COARSE enables a controlled trade-off between the physical layer data rate per user and the number of users communicating using a given resource. Significantly, COARSE provides 25–75% improvement in the computed user-perceived video quality compared with that obtained from an equivalent single-hop network.

In recent years, there has been an exponential increase in the number of mobile phone users. In addition, a significant growth in the demand for high-rate multimedia services over wireless networks, such as video conferencing, multimedia streaming, etc., was noted. Different solutions were proposed to support high-quality high data rate delivery to mobile users, including resource allocation techniques for packet-radio-based next generation cellular networks. In this paper, an efficient time slot allocation method-Dynamic Time Slot Partitioning (DTSP) algorithm based on statistical multiplexing is proposed for a two-hop cellular architecture. In DTSP, the available bandwidth resources are increased by partitioning each time slot into several minislots wherein different numbers of minislots are allocated to different users. The DTSP algorithm is based on asynchronous time-division multiplexing, wherein users with variable number of packets in their buffers can transmit data sequentially without any loss in the overall available resources. The key advantage of DTSP is that it can flexibly adapt to different quality of service requirements, especially when combined with adaptive modulation. It has been observed that the system capacity achieved by the DTSP algorithm in the downlink mode using adaptive modulation is up to 41 percent higher than when existing solutions are employed. In addition, DTSP results in significantly lower time for data transmission than the state-of-the-art region and time partitioning techniques.

Real-time multimedia communications over vehicular ad-hoc networks (VANET) will play an extremely significant role in the next generation intelligent transport systems. In recent years, there has been an upsurge of interest in the quality-oriented adaptive multimedia delivery, including over VANET. In this paper, a hybrid IEEE 802.11p-based multihop network communication solution is presented, which makes use of both in frastructure and ad-hoc modes in order to deliver quality-oriented real-time multimedia content to high-speed vehicles. Simulation-based testing shows how multimedia delivery to vehicles when using the multihop hybrid mechanism achieves significantly higher throughput in comparison to the case when the in frastructure mode is employed and the vehicles communicate directly with the base station. This result is obtained while the average delay and packet loss in the two cases are similar.

Over the last number of years, smart mobile devices have been rapidly replacing computers as the most commonly-used web-access devices. Mobile device capabilities have improved exponentially with time, when compared with the relatively small increase in their battery life. This has had a serious impact on these devices' practical use, especially for multimedia streaming and video-on-demand applications. This paper proposes a cross-layer Battery and Stream-Aware Adaptive Multimedia Delivery mechanism (BaSe-AMy) that monitors mobile device remaining battery level, remaining video stream duration and packet loss rate. BaSe-AMy makes use of these values to decide whether or not video quality adaptation is required in order to achieve power saving, while also maintaining good user perceived Quality of Service (QoS) levels. The proposed mechanism is evaluated and compared with a non-adaptive scheme in terms of battery duration and video quality (expressed in terms of Peak Signal-to-Noise Ratio - PSNR). It is shown that such a mechanism not only results in an increase in battery life by up to 18%, but also raises the video quality by up to 4%.

In this paper, the effect of variation in the spatial protection margin, is investigated for multihop wireless networks under the interference avoidance protocol model and compared to single-hop communication network. Under the protocol model, the interference is avoided by the application of the exclusion range concept. This means that a spatial protection region (or a circular exclusion region) is specified around all receiving nodes so that any node other than the intended transmitter is not allowed to reuse the same frequency resource within this region. It is demonstrated that for an asymptotically infinite coverage area, the spatial reuse efficiency for a multihop design increases proportionally with the number of multiple hops per link, and with the spatial protection margin. However, under a finite coverage area, the monotonic increase of spatial reuse efficiency does not remain completely valid. In order to analyze the performance of such a system, a relation for the system throughput is derived from the Shannon capacity equation. It is found that the system throughput attains a peak when the value of spatial protection margin is nearly unity. The exact value of spatial protection margin when the throughput reaches its maximum is found to be a monotonically increasing function of the number of multiple hops and the pathloss exponent.

A multihop ad hoc wireless network with an interference avoidance model is analyzed for a time division duplex (TDD) air-interface. In accordance with the non-interference protocol, an exclusion region is defined around every communicating receiver wherein no other node except the desired transmitter can transmit. In a network comprising finite coverage area, the position of the communicating nodes determine the number of simultaneous communicating pairs and hence the overall system throughput. A random data hopping technique for a time slot (TS) partitioned system is proposed in this paper. In this technique, the number of TS(s) in the TDMA frame is increased by reducing the duration of each TS. Then, the time slots over which the transmission pairs of the end-to-end link communicate are randomly assigned over the time frame. This randomness combined with a high TS granularity results in an increased system throughput of up to 31% as compared to a system with low TS granularity

Orthogonal frequency division multiplexing (OFDM) is very sensitive to frequency offsets which result in considerable interference. Performance of the system will be exacerbated in the uplink of a cellular deployment with frequency reuse of one. A general mathematical model is developed to calculate the amount of interference in cellular OFDM system considering frequency offset between transmitter (Tx) and receiver (Rx), depending on different multiple access and duplexing techniques. An ideal adaptive modulation scheme is applied to compare the capacity of different cellular OFDM systems. It is found that the capacity of frequency division multiple access (FDMA) system outperforms that of time division multiple access (TDMA) system due to multiuser diversity in FDMA. Moreover, time division duplexing (TDD) system outperforms frequency division duplexing (FDD) system irrespective of the multiple access techniques by exploiting time slot (TS) opposing techniques.

In this paper different scheduling algorithms applied to cellular CDMA (code division multiple access) systems with different duplexing modes are studied. In particular, the performance of cellular CDMA-TDD (time division duplex) with random uplink (UL)/downlink (DL) assignment is compared to cellular CDMA-FDD (frequency division duplex) systems. The random UL/DL assignment in TDD is previously reported as random time slot opposing (RTSO), and it was shown that this technique results in interference diversity when used in a cellular system. It is demonstrated in this paper that scheduling algorithms can effectively exploit this interference diversity to enhance the total spectral efficiency. Throughput, outage and average transmit power are used to compare the performance. First, it can be observed that, despite additional interference sources in TDD, TDD and FDD result in about the same throughput and outage performance for a cellular deployment. However, the stepwise rate removal (SRR) algorithm results in significantly improved outage in TDD. Second, regardless of the duplexing technique the results show that a general improvement in throughput is always at the cost of the number of users served.

A hybrid cellular and ad hoc network for high data rate wireless access is considered. An air-interface which uses TDD in combination with time division multiple access (TDMA) is assumed. Interference and resource reuse are important issues in hybrid networks. For this purpose analytical models for the reuse efficiency and a capacity bound of such a network are developed. These models are based on an exclusion range concept which is introduced to keep interference at an acceptable level. It is found that with this interference limiting measure, multi hop networks can benefit from a multi hop reuse gain compared to single hop networks. However, it is further found that this gain does not significantly increase for more than 5 hops. Furthermore, the pre-requisite for being able to exploit the multi hop reuse gain is a certain TS granularity. It was observed that with an increasing number of TS per frame, the mean and the variance of the number of supported hops increased almost linearly