Sharif Digital Repository

In this paper, we propose an analytical framework in order to compute the throughput capacity of a multi-hop ad hoc network with a finite number of mobile wireless nodes. The proposed framework consists of two related queueing networks; a closed BCMP queueing network to represent the mobility model of the wireless nodes and an open BCMP queueing network comprising symmetric M/G/l nodes to represent the multi-hop packet routing process from sources to destinations. In this respect, we consider very simple MAC and routing schemes and then map the related parameters onto several components of the queueing network. By solving the linear traffic equations corresponding to concerned queueing... 

Analytical models exist for evaluating gossip-based information propagation. Up to now these models were developed only for fully connected networks. We provide analytical models for information propagation of a push-pull gossiping protocol in a wireless mesh network. The underlying topology is abstracted away by assuming that the wireless nodes are uniformly deployed. We compare our models with simulation results for different topologies  

In this paper, we evaluate the saturation throughput for an IEEE 802.11 based wireless network considering capture effect at the receiver, while nodes transmit with random powers. In this respect, we consider a scenario consisting of a specific number of wireless nodes. Then, we derive the transmission as well as collision probabilities with respect to the perfect capture effect. In order to maximize the saturation throughput we set up an optimization problem and obtain how to compute optimum values for the probabilities corresponding to different power levels. By providing the numerical results, we deduce that power randomization may lead to a significant improvement in saturation... 

In this paper, we evaluate the effect of energy constraints on the performance of a simple network comprised of wireless nodes with energy harvesting capability. In this scenario, wireless nodes contend with each other based on slotted Aloha protocol in order to transmit a packet. Packet transmission occurs provided that enough energy exists in the energy buffer. We propose an analytical model based on a closed queueing network (QN) to include details of data and energy buffers as well as random access MAC protocol. We show how energy limitation affects the MAC design parameters, e.g., contention window size, in order to optimize the performance of the network. Moreover, we evaluate the... 

In this paper, an underwater wireless sensor network (UWSN) is modeled with the help of queueing theory in order to evaluate the maximum stable throughput of the network. To this end, a new scenario for multi-layer mobile UWSN is considered. Then, a new MAC algorithm comprised of random access scheme (like MACAW) and CDMA-based data transmission along with a simplified routing algorithm is proposed. In order to analyze the considered UWSN scenario, we propose two related queueing networks, one for modeling the wireless node mobility and the other for representing the process of multi-hop packet transmission according to considered MAC and routing algorithms. Finally, the maximum stable... 

In this paper, we focus on a cognitive network scenario, comprised of a multi-hop IEEE 802.11-based WLAN overlaid on a cellular network. In this scenario, the wireless nodes in a WLAN, i.e., cognitive nodes, use the downlink frequency channels of the cellular network opportunistically, such that at each packet transmission all idle channels have been exploited. In order to evaluate the capability of the considered cognitive network scenario, we propose an open queueing network model such that different packet transmission phases are mapped onto different queueing nodes. We also map different types of collisions, i.e., collision on control signals as well as collision on data transmission due... 

Performance of routing is severely degraded when misbehaving nodes drop packets instead of properly forwarding them. In this paper, we propose a Game-Theoretic Adaptive Multipath Routing (GTAMR) protocol to detect and punish selfish or malicious nodes which try to drop information packets in routing phase and defend against collaborative attacks in which nodes try to disrupt communication or save their power. Our proposed algorithm outranks previous schemes because it is resilient against attacks in which more than one node coordinate their misbehavior and can be used in networks which wireless nodes use directional antennas. We then propose a game theoretic strategy, ERTFT, for nodes to... 

In this paper, we propose a new analytical model for stable throughput evaluation of wireless network coding. In this new approach we consider the arrival and departure rates in and from the wireless nodes, respectively, in steady state. Our analytical model is founded on a multi-class open queueing network. In this model, we include two basic processes of network coding, i.e., packets combination and packets multicasting, in a suitable manner considering the constraints of the queueing networks. In this respect, we consider the coded packets as new classes of customers. By solving the related traffic equations and applying the stability condition, we compute the maximum stable throughput,... 

In this paper, we propose a new analytical model in order to evaluate the throughput of a wireless tandem network coding. Our analytical model is based on a multi-class open queueing network. In this model, we include two basic processes of network coding, i.e., packets combination and packets multicasting, in a suitable way considering the constraints of the queueing networks. To this end, we consider the coded packets as new classes of customers. In our model we consider the arrival and departure rates in and from the wireless nodes in steady state. By solving the related traffic equations and applying the stability condition, we compute the maximum stable throughput, i.e., the maximum... 

Wireless mesh networks (WMNs) are well-promising future networks especially for ubiquitous connection to Internet. In this paper, we propose an analytical model in order to evaluate the maximum stable throughput of a WMN based on a simplified version of IEEE 802.11s MAC protocol. Our modeling approach is based on a multi-class open queueing network. In this respect, we map some of the important features of IEEE 802.11s MAC protocol, esp., its contention-based and contention-free periods onto different parameters of the proposed queueing network. By solving the related traffic equations and applying the stability condition, we determine the maximum stable throughput, i.e., the maximum packet... 

Mobile Ad Hoc Networks (MANETs) are networks with selforganizing capabilities and without a fixed infrastructure. Wireless nodes communicate among themselves using multi-hop radio relaying, without requiring the packets to pass through a central access point or a base station. In a highly mobile and infrastructure-less scenario, pre-configuration of addresses is not possible. Therefore node addresses need to be configured dynamically with minimum delay and packet loss. Existing solutions for IP address auto-configuration do not address security issues. In this paper we propose a secure address autoconfiguration for Mobile Ad hoc Networks (MANET) based on Virtual Address Space Mapping [1]....