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M2M applications exhibit a wide variety of QoS requirements, but many, particularly those associated with monitoring and/or control, are delay sensitive and therefore have specific packet delay budgets. One of the issues when supporting such delay sensitive M2M applications over a wide area cellular standard such as LTE is that the base station scheduling entity cannot precisely ascertain when pending uplink packets at devices were generated. This makes scheduling according to deadlines based upon packet delay budgets very challenging and ultimately involves some degree of error. In this paper, we propose a new delay sensitive scheduler that increases the probability of satisfying the delay budget of packets by exploiting Packet Age (PA) data explicitly reported by devices. The PA is a new MAC Control Element that represents the age of the oldest pending packet in the device buffers and is sent by devices in parallel with the existing Buffer Status Report (BSR) that contains volume and priority data. The overhead associated with the PA MAC control element is extremely small (2 bytes). We demonstrate the performance of the new technique with an OPNET simulation of an LTE TDD system serving event driven delay sensitive M2M traffic, comparing the results when PA reporting is enabled versus disabled for essentially the same uplink scheduling algorithm. [ABSTRACT FROM PUBLISHER]

Vehicular ad hoc network is considered as an integral part of the future intelligent transportation system. As the number of applications which are supported by the vehicular communication grow, the efficient utilization of the control channel and congestion control become important issues. The periodic broadcast of basic safety messages (BSM) by the vehicles consumes most of the control channel interval, leaving less transmission capacity for other types of traffic. To accommodate the data packets from other safety and non-safety applications, the packet transmission rate of BSM must be controlled without compromising the safety of the vehicles. In this paper, we present a BSM generation rate control algorithm based on the measured time headway of the vehicles. The performance analysis shows that the proposed rate control algorithm reduces the channel utilization and improves the BSM reception ratio at different vehicle densities and vehicle speeds. Moreover, the proposed rate control algorithm effectively reduces the notification time of a multi-hop warning message. [ABSTRACT FROM PUBLISHER]

Safety applications in VANETs relies on various type of information exchanges among vehicles of which Cooperative Awareness Message (CAM) has the largest share in the network load due to their periodic broadcast nature. As the vehicle density grows, the load generated by the CAMs could increase beyond the transmission capacity of a VANET resulting in the loss of neighborhood information and a higher utilization of the control channel. In this paper, we present the concept of a safety zone to adaptively control the transmit power of CAMs to restrict the network load without compromising the safety features of VANET applications. Moreover, we also introduce a new cooperative information sharing technique to increase the vehicle's awareness beyond the transmission range. The simulation results show that the proposed technique could significantly reduce the packet losses and channel utilization for a range of vehicle densities. [ABSTRACT FROM PUBLISHER]

This paper investigates the performance of a distributed EV load management scheme, suggested in [1], [2], integrated in a realistic wide area wireless communications network based on WiMAX technology. Using an integrated co-simulation model developed in OPNET, the paper jointly examines the performance of the EV charging scheme and the communications network under varying EV population and power limitation. Based on the study, the paper proposes two simple adaptations to the proposed scheme in order to improve its controllability over the aggregated demand and scalability regarding both the EV population and the power limit. Simulation results indicate that the proposed adaptation can support large-scale EV charging at a fixed communications overhead in a scalable and efficient manner. [ABSTRACT FROM PUBLISHER]

This paper proposes a end-to-end load management scheme for domestic charging of electric vehicles (EVs) based on the bidirectional communication capabilities of the smart grid. In particular, the paper considers the case of using EV fleets for night-time valley-filling of the daily load curve. The novel concept of discontinuous EV charging based on small energy bursts is introduced that utilizes the benefit of the statistical multiplexing to accommodate higher number of vehicles and to provide differentiated energy supply against a variable energy-budget within a pre-defined time. The paper also suggests two energy scheduling algorithms to ensure priority and/or fairness among the contending vehicles. A wide-area smart grid communications network based on WiMAX technology has been used as a proof of concept for this study. Simulations are conducted using an integrated OPNET model to jointly examine the performances of the energy scheduling algorithms and the communications network for a large-scale EV charging system. The results show that the proposed scheme can efficiently support the EV charging load in an equitable manner with a very low communications overhead. [ABSTRACT FROM PUBLISHER]

With the increasing use of smart phones and other portable communications devices the role of WLAN is increasing. The IEEE 802.11 based WLAN is almost becoming the de facto broadband wireless access network. Due to widespread usage of portable devices the demand for energy efficient networking is increasing. It is necessary to design energy efficient algorithms to prolong the battery life of mobile devices. In this paper, we propose a new link adaptation based energy efficient packet transmission technique for the IEEE802.11g standard. The proposed protocol maintains the QoS of different classes of service at the same time it reduces energy requirements of WLAN based devices thus prolonging the battery life of user devices. The performance of the proposed packet transmission technique is analysed using an OPNET based discrete event simulation model. Simulation results show that the proposed protocol can considerably reduce the energy requirements of mobile devices for data transmission. [ABSTRACT FROM PUBLISHER]

The Long Term Evolution (LTE) standard is one of the most promising wireless access technologies for Machine to Machine (M2M) communications because of its high data rates, low latency and economies of scale. M2M communications typically involves a large number of autonomous devices sending traffic in a coordinated manner (and possibly even simultaneously), therefore creating an uplink-heavy trend which needs an efficient radio resource management scheme. The conventional scheduling algorithms and performance metrics are not suitable for M2M systems because of the different characteristics and service requirements of M2M traffic. In this paper, we analyze the performance of an enhanced delay sensitive uplink scheduler in context of LTE TDD configurations 0 and 1 for delay sensitive event based M2M traffic. We show that unlike an ordinary equal capacity fair scheduler, our proposed delay sensitive scheduler can make utmost use of the maximally uplink-biased TDD configuration 0, attaining higher capacity and maximizing the chance of satisfying packet delay budget of M2M traffic. We also introduce a new performance metric called “Effective Allocated Bits/RB pair” to measure the allocation efficiency of a scheduler, evaluate the performance of the proposed scheduler in terms of this metric and identify the scope of possible improvements. [ABSTRACT FROM PUBLISHER]

A smart grid communication network will enable the electricity operators to connect various intelligent devices, smart meters and other sensors to different servers located within the electricity grid. Automated meter reading is a key feature of a smart grid which requires installation of a communication network that can access 100% of smart meters within its coverage area. Smart meter connectivity in inner cities is a challenging problem due to the location of meters inside high rise buildings as well as due to difficult propagation conditions. In this paper we analyze the connectivity pattern of smart meters in an inner city environment using an IEEE 802.16e based WiMAX network. The paper initially models the inner city propagation environment to study the connectivity pattern. Based on the propagation model the work developed a transmission power ramping algorithm to provide 100% meter connectivity. Simulation models were developed based on OPNET and MATLAB packages. [ABSTRACT FROM PUBLISHER]

Neighborhood Area Network (NAN) is a key component of a smart grid communication network infrastructure. A NAN generally works as an access network connecting all the customer equipment and some field devices to the smart grid communication infrastructure to exchange data and control information. NANs can be designed based on infrastructure based access network such as WiMAX or LTE based system to cover a wide geographic area. However, one of the main problems for such NAN architecture is that a centralized base station based system may not be able to provide connectivity to all user equipment or field devices due to presence of low SNR regions with radio coverage area of a base station. To ensure 100% connectivity of NAN devices use of radio mesh networks are now actively being considered by the researchers and electricity utilities and companies. This paper presents a 6LoWPAN based NAN architecture designed to serve all smart meters in a NAN coverage area and also to maintain QoS requirements of different applications within NANs. T his p aper a nalyse t he p erformance o f a 6 LoWPAN based basic radio mesh network using a newly develop discrete event simulation model using the OPNET network modeling package. [ABSTRACT FROM PUBLISHER]